PostgreSQL Source Code  git master
verify_nbtree.c File Reference
#include "postgres.h"
#include "access/htup_details.h"
#include "access/nbtree.h"
#include "access/table.h"
#include "access/tableam.h"
#include "access/transam.h"
#include "access/xact.h"
#include "catalog/index.h"
#include "catalog/pg_am.h"
#include "commands/tablecmds.h"
#include "lib/bloomfilter.h"
#include "miscadmin.h"
#include "storage/lmgr.h"
#include "storage/smgr.h"
#include "utils/memutils.h"
#include "utils/snapmgr.h"
Include dependency graph for verify_nbtree.c:

Go to the source code of this file.

Data Structures

struct  BtreeCheckState
 
struct  BtreeLevel
 

Macros

#define InvalidBtreeLevel   ((uint32) InvalidBlockNumber)
 
#define BTreeTupleGetNKeyAtts(itup, rel)   Min(IndexRelationGetNumberOfKeyAttributes(rel), BTreeTupleGetNAtts(itup, rel))
 

Typedefs

typedef struct BtreeCheckState BtreeCheckState
 
typedef struct BtreeLevel BtreeLevel
 

Functions

 PG_FUNCTION_INFO_V1 (bt_index_check)
 
 PG_FUNCTION_INFO_V1 (bt_index_parent_check)
 
static void bt_index_check_internal (Oid indrelid, bool parentcheck, bool heapallindexed, bool rootdescend)
 
static void btree_index_checkable (Relation rel)
 
static bool btree_index_mainfork_expected (Relation rel)
 
static void bt_check_every_level (Relation rel, Relation heaprel, bool heapkeyspace, bool readonly, bool heapallindexed, bool rootdescend)
 
static BtreeLevel bt_check_level_from_leftmost (BtreeCheckState *state, BtreeLevel level)
 
static void bt_recheck_sibling_links (BtreeCheckState *state, BlockNumber btpo_prev_from_target, BlockNumber leftcurrent)
 
static void bt_target_page_check (BtreeCheckState *state)
 
static BTScanInsert bt_right_page_check_scankey (BtreeCheckState *state)
 
static void bt_child_check (BtreeCheckState *state, BTScanInsert targetkey, OffsetNumber downlinkoffnum)
 
static void bt_child_highkey_check (BtreeCheckState *state, OffsetNumber target_downlinkoffnum, Page loaded_child, uint32 target_level)
 
static void bt_downlink_missing_check (BtreeCheckState *state, bool rightsplit, BlockNumber targetblock, Page target)
 
static void bt_tuple_present_callback (Relation index, ItemPointer tid, Datum *values, bool *isnull, bool tupleIsAlive, void *checkstate)
 
static IndexTuple bt_normalize_tuple (BtreeCheckState *state, IndexTuple itup)
 
static IndexTuple bt_posting_plain_tuple (IndexTuple itup, int n)
 
static bool bt_rootdescend (BtreeCheckState *state, IndexTuple itup)
 
static bool offset_is_negative_infinity (BTPageOpaque opaque, OffsetNumber offset)
 
static bool invariant_l_offset (BtreeCheckState *state, BTScanInsert key, OffsetNumber upperbound)
 
static bool invariant_leq_offset (BtreeCheckState *state, BTScanInsert key, OffsetNumber upperbound)
 
static bool invariant_g_offset (BtreeCheckState *state, BTScanInsert key, OffsetNumber lowerbound)
 
static bool invariant_l_nontarget_offset (BtreeCheckState *state, BTScanInsert key, BlockNumber nontargetblock, Page nontarget, OffsetNumber upperbound)
 
static Page palloc_btree_page (BtreeCheckState *state, BlockNumber blocknum)
 
static BTScanInsert bt_mkscankey_pivotsearch (Relation rel, IndexTuple itup)
 
static ItemId PageGetItemIdCareful (BtreeCheckState *state, BlockNumber block, Page page, OffsetNumber offset)
 
static ItemPointer BTreeTupleGetHeapTIDCareful (BtreeCheckState *state, IndexTuple itup, bool nonpivot)
 
static ItemPointer BTreeTupleGetPointsToTID (IndexTuple itup)
 
Datum bt_index_check (PG_FUNCTION_ARGS)
 
Datum bt_index_parent_check (PG_FUNCTION_ARGS)
 
static bool bt_pivot_tuple_identical (bool heapkeyspace, IndexTuple itup1, IndexTuple itup2)
 

Variables

 PG_MODULE_MAGIC
 

Macro Definition Documentation

◆ BTreeTupleGetNKeyAtts

#define BTreeTupleGetNKeyAtts (   itup,
  rel 
)    Min(IndexRelationGetNumberOfKeyAttributes(rel), BTreeTupleGetNAtts(itup, rel))

Definition at line 50 of file verify_nbtree.c.

Referenced by invariant_l_nontarget_offset(), and invariant_l_offset().

◆ InvalidBtreeLevel

#define InvalidBtreeLevel   ((uint32) InvalidBlockNumber)

Definition at line 49 of file verify_nbtree.c.

Referenced by bt_check_every_level(), and bt_check_level_from_leftmost().

Typedef Documentation

◆ BtreeCheckState

◆ BtreeLevel

typedef struct BtreeLevel BtreeLevel

Function Documentation

◆ bt_check_every_level()

static void bt_check_every_level ( Relation  rel,
Relation  heaprel,
bool  heapkeyspace,
bool  readonly,
bool  heapallindexed,
bool  rootdescend 
)
static

Definition at line 419 of file verify_nbtree.c.

References ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate, Assert, BAS_BULKREAD, bloom_create(), bloom_free(), bloom_prop_bits_set(), bt_check_level_from_leftmost(), bt_tuple_present_callback(), BTMetaPageData::btm_fastlevel, BTMetaPageData::btm_fastroot, BTMetaPageData::btm_level, BTMetaPageData::btm_root, BTPageGetMeta, BTREE_METAPAGE, BuildIndexInfo(), BtreeCheckState::checkstrategy, CurrentMemoryContext, DEBUG1, elog, ereport, errcode(), errdetail_internal(), errhint(), errmsg(), errmsg_internal(), ERROR, BtreeCheckState::filter, GetAccessStrategy(), GetTransactionSnapshot(), BtreeCheckState::heapallindexed, BtreeCheckState::heapkeyspace, BtreeCheckState::heaprel, HeapTupleHeaderGetXmin, BtreeCheckState::heaptuplespresent, IndexInfo::ii_Concurrent, IndexInfo::ii_ExclusionOps, IndexInfo::ii_ExclusionProcs, IndexInfo::ii_ExclusionStrats, IndexInfo::ii_Unique, INT64_FORMAT, InvalidBlockNumber, InvalidBtreeLevel, IsolationUsesXactSnapshot, BtreeLevel::istruerootlevel, BtreeLevel::leftmost, BtreeLevel::level, maintenance_work_mem, Max, MaxTIDsPerBTreePage, MemoryContextDelete(), P_NONE, palloc0(), palloc_btree_page(), random(), RelationData::rd_index, RelationData::rd_indextuple, RelationData::rd_rel, BtreeCheckState::readonly, RecentXmin, RegisterSnapshot(), BtreeCheckState::rel, RelationGetNumberOfBlocks, RelationGetRelationName, BtreeCheckState::rootdescend, SnapshotAny, HeapTupleData::t_data, table_beginscan_strat(), table_index_build_scan(), BtreeCheckState::targetcontext, TransactionIdIsValid, TransactionIdPrecedes(), UnregisterSnapshot(), and SnapshotData::xmin.

Referenced by bt_index_check_internal().

421 {
423  Page metapage;
424  BTMetaPageData *metad;
425  uint32 previouslevel;
426  BtreeLevel current;
427  Snapshot snapshot = SnapshotAny;
428 
429  if (!readonly)
430  elog(DEBUG1, "verifying consistency of tree structure for index \"%s\"",
432  else
433  elog(DEBUG1, "verifying consistency of tree structure for index \"%s\" with cross-level checks",
435 
436  /*
437  * This assertion matches the one in index_getnext_tid(). See page
438  * recycling/"visible to everyone" notes in nbtree README.
439  */
441 
442  /*
443  * Initialize state for entire verification operation
444  */
445  state = palloc0(sizeof(BtreeCheckState));
446  state->rel = rel;
447  state->heaprel = heaprel;
448  state->heapkeyspace = heapkeyspace;
449  state->readonly = readonly;
450  state->heapallindexed = heapallindexed;
451  state->rootdescend = rootdescend;
452 
453  if (state->heapallindexed)
454  {
455  int64 total_pages;
456  int64 total_elems;
457  uint64 seed;
458 
459  /*
460  * Size Bloom filter based on estimated number of tuples in index,
461  * while conservatively assuming that each block must contain at least
462  * MaxTIDsPerBTreePage / 3 "plain" tuples -- see
463  * bt_posting_plain_tuple() for definition, and details of how posting
464  * list tuples are handled.
465  */
466  total_pages = RelationGetNumberOfBlocks(rel);
467  total_elems = Max(total_pages * (MaxTIDsPerBTreePage / 3),
468  (int64) state->rel->rd_rel->reltuples);
469  /* Random seed relies on backend srandom() call to avoid repetition */
470  seed = random();
471  /* Create Bloom filter to fingerprint index */
472  state->filter = bloom_create(total_elems, maintenance_work_mem, seed);
473  state->heaptuplespresent = 0;
474 
475  /*
476  * Register our own snapshot in !readonly case, rather than asking
477  * table_index_build_scan() to do this for us later. This needs to
478  * happen before index fingerprinting begins, so we can later be
479  * certain that index fingerprinting should have reached all tuples
480  * returned by table_index_build_scan().
481  */
482  if (!state->readonly)
483  {
485 
486  /*
487  * GetTransactionSnapshot() always acquires a new MVCC snapshot in
488  * READ COMMITTED mode. A new snapshot is guaranteed to have all
489  * the entries it requires in the index.
490  *
491  * We must defend against the possibility that an old xact
492  * snapshot was returned at higher isolation levels when that
493  * snapshot is not safe for index scans of the target index. This
494  * is possible when the snapshot sees tuples that are before the
495  * index's indcheckxmin horizon. Throwing an error here should be
496  * very rare. It doesn't seem worth using a secondary snapshot to
497  * avoid this.
498  */
499  if (IsolationUsesXactSnapshot() && rel->rd_index->indcheckxmin &&
501  snapshot->xmin))
502  ereport(ERROR,
503  (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
504  errmsg("index \"%s\" cannot be verified using transaction snapshot",
505  RelationGetRelationName(rel))));
506  }
507  }
508 
509  Assert(!state->rootdescend || state->readonly);
510  if (state->rootdescend && !state->heapkeyspace)
511  ereport(ERROR,
512  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
513  errmsg("cannot verify that tuples from index \"%s\" can each be found by an independent index search",
515  errhint("Only B-Tree version 4 indexes support rootdescend verification.")));
516 
517  /* Create context for page */
519  "amcheck context",
522 
523  /* Get true root block from meta-page */
524  metapage = palloc_btree_page(state, BTREE_METAPAGE);
525  metad = BTPageGetMeta(metapage);
526 
527  /*
528  * Certain deletion patterns can result in "skinny" B-Tree indexes, where
529  * the fast root and true root differ.
530  *
531  * Start from the true root, not the fast root, unlike conventional index
532  * scans. This approach is more thorough, and removes the risk of
533  * following a stale fast root from the meta page.
534  */
535  if (metad->btm_fastroot != metad->btm_root)
536  ereport(DEBUG1,
537  (errcode(ERRCODE_NO_DATA),
538  errmsg("harmless fast root mismatch in index %s",
540  errdetail_internal("Fast root block %u (level %u) differs from true root block %u (level %u).",
541  metad->btm_fastroot, metad->btm_fastlevel,
542  metad->btm_root, metad->btm_level)));
543 
544  /*
545  * Starting at the root, verify every level. Move left to right, top to
546  * bottom. Note that there may be no pages other than the meta page (meta
547  * page can indicate that root is P_NONE when the index is totally empty).
548  */
549  previouslevel = InvalidBtreeLevel;
550  current.level = metad->btm_level;
551  current.leftmost = metad->btm_root;
552  current.istruerootlevel = true;
553  while (current.leftmost != P_NONE)
554  {
555  /*
556  * Verify this level, and get left most page for next level down, if
557  * not at leaf level
558  */
559  current = bt_check_level_from_leftmost(state, current);
560 
561  if (current.leftmost == InvalidBlockNumber)
562  ereport(ERROR,
563  (errcode(ERRCODE_INDEX_CORRUPTED),
564  errmsg("index \"%s\" has no valid pages on level below %u or first level",
565  RelationGetRelationName(rel), previouslevel)));
566 
567  previouslevel = current.level;
568  }
569 
570  /*
571  * * Check whether heap contains unindexed/malformed tuples *
572  */
573  if (state->heapallindexed)
574  {
575  IndexInfo *indexinfo = BuildIndexInfo(state->rel);
576  TableScanDesc scan;
577 
578  /*
579  * Create our own scan for table_index_build_scan(), rather than
580  * getting it to do so for us. This is required so that we can
581  * actually use the MVCC snapshot registered earlier in !readonly
582  * case.
583  *
584  * Note that table_index_build_scan() calls heap_endscan() for us.
585  */
586  scan = table_beginscan_strat(state->heaprel, /* relation */
587  snapshot, /* snapshot */
588  0, /* number of keys */
589  NULL, /* scan key */
590  true, /* buffer access strategy OK */
591  true); /* syncscan OK? */
592 
593  /*
594  * Scan will behave as the first scan of a CREATE INDEX CONCURRENTLY
595  * behaves in !readonly case.
596  *
597  * It's okay that we don't actually use the same lock strength for the
598  * heap relation as any other ii_Concurrent caller would in !readonly
599  * case. We have no reason to care about a concurrent VACUUM
600  * operation, since there isn't going to be a second scan of the heap
601  * that needs to be sure that there was no concurrent recycling of
602  * TIDs.
603  */
604  indexinfo->ii_Concurrent = !state->readonly;
605 
606  /*
607  * Don't wait for uncommitted tuple xact commit/abort when index is a
608  * unique index on a catalog (or an index used by an exclusion
609  * constraint). This could otherwise happen in the readonly case.
610  */
611  indexinfo->ii_Unique = false;
612  indexinfo->ii_ExclusionOps = NULL;
613  indexinfo->ii_ExclusionProcs = NULL;
614  indexinfo->ii_ExclusionStrats = NULL;
615 
616  elog(DEBUG1, "verifying that tuples from index \"%s\" are present in \"%s\"",
619 
620  table_index_build_scan(state->heaprel, state->rel, indexinfo, true, false,
621  bt_tuple_present_callback, (void *) state, scan);
622 
623  ereport(DEBUG1,
624  (errmsg_internal("finished verifying presence of " INT64_FORMAT " tuples from table \"%s\" with bitset %.2f%% set",
626  100.0 * bloom_prop_bits_set(state->filter))));
627 
628  if (snapshot != SnapshotAny)
629  UnregisterSnapshot(snapshot);
630 
631  bloom_free(state->filter);
632  }
633 
634  /* Be tidy: */
636 }
BufferAccessStrategy GetAccessStrategy(BufferAccessStrategyType btype)
Definition: freelist.c:542
bloom_filter * bloom_create(int64 total_elems, int bloom_work_mem, uint64 seed)
Definition: bloomfilter.c:88
void MemoryContextDelete(MemoryContext context)
Definition: mcxt.c:212
#define AllocSetContextCreate
Definition: memutils.h:170
#define DEBUG1
Definition: elog.h:25
int errhint(const char *fmt,...)
Definition: elog.c:1068
static BtreeLevel bt_check_level_from_leftmost(BtreeCheckState *state, BtreeLevel level)
Snapshot RegisterSnapshot(Snapshot snapshot)
Definition: snapmgr.c:810
static Page palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum)
uint32 level
long random(void)
Definition: random.c:22
static void bt_tuple_present_callback(Relation index, ItemPointer tid, Datum *values, bool *isnull, bool tupleIsAlive, void *checkstate)
#define IsolationUsesXactSnapshot()
Definition: xact.h:51
#define P_NONE
Definition: nbtree.h:206
Oid * ii_ExclusionProcs
Definition: execnodes.h:165
int errcode(int sqlerrcode)
Definition: elog.c:610
TransactionId RecentXmin
Definition: snapmgr.c:113
IndexInfo * BuildIndexInfo(Relation index)
Definition: index.c:2301
#define MaxTIDsPerBTreePage
Definition: nbtree.h:179
Form_pg_class rd_rel
Definition: rel.h:109
BufferAccessStrategy checkstrategy
Definition: verify_nbtree.c:84
Snapshot GetTransactionSnapshot(void)
Definition: snapmgr.c:250
static TableScanDesc table_beginscan_strat(Relation rel, Snapshot snapshot, int nkeys, struct ScanKeyData *key, bool allow_strat, bool allow_sync)
Definition: tableam.h:779
bloom_filter * filter
int errdetail_internal(const char *fmt,...)
Definition: elog.c:981
struct HeapTupleData * rd_indextuple
Definition: rel.h:176
HeapTupleHeader t_data
Definition: htup.h:68
Form_pg_index rd_index
Definition: rel.h:174
BlockNumber btm_fastroot
Definition: nbtree.h:104
#define ERROR
Definition: elog.h:43
static double table_index_build_scan(Relation table_rel, Relation index_rel, struct IndexInfo *index_info, bool allow_sync, bool progress, IndexBuildCallback callback, void *callback_state, TableScanDesc scan)
Definition: tableam.h:1552
#define ALLOCSET_DEFAULT_SIZES
Definition: memutils.h:192
#define BTPageGetMeta(p)
Definition: nbtree.h:114
BlockNumber leftmost
#define RelationGetRelationName(relation)
Definition: rel.h:490
unsigned int uint32
Definition: c.h:375
TransactionId xmin
Definition: snapshot.h:157
MemoryContext CurrentMemoryContext
Definition: mcxt.c:38
#define BTREE_METAPAGE
Definition: nbtree.h:141
bool TransactionIdPrecedes(TransactionId id1, TransactionId id2)
Definition: transam.c:300
void UnregisterSnapshot(Snapshot snapshot)
Definition: snapmgr.c:852
void bloom_free(bloom_filter *filter)
Definition: bloomfilter.c:127
Relation heaprel
Definition: verify_nbtree.c:72
uint32 btm_fastlevel
Definition: nbtree.h:105
void * palloc0(Size size)
Definition: mcxt.c:981
BlockNumber btm_root
Definition: nbtree.h:102
#define RelationGetNumberOfBlocks(reln)
Definition: bufmgr.h:211
#define ereport(elevel,...)
Definition: elog.h:144
int maintenance_work_mem
Definition: globals.c:123
int errmsg_internal(const char *fmt,...)
Definition: elog.c:908
bool ii_Unique
Definition: execnodes.h:171
#define Max(x, y)
Definition: c.h:922
#define Assert(condition)
Definition: c.h:746
Definition: regguts.h:298
#define HeapTupleHeaderGetXmin(tup)
Definition: htup_details.h:313
#define InvalidBlockNumber
Definition: block.h:33
bool ii_Concurrent
Definition: execnodes.h:173
#define INT64_FORMAT
Definition: c.h:417
#define SnapshotAny
Definition: snapmgr.h:68
double bloom_prop_bits_set(bloom_filter *filter)
Definition: bloomfilter.c:188
Oid * ii_ExclusionOps
Definition: execnodes.h:164
int errmsg(const char *fmt,...)
Definition: elog.c:821
uint32 btm_level
Definition: nbtree.h:103
#define elog(elevel,...)
Definition: elog.h:214
bool istruerootlevel
#define InvalidBtreeLevel
Definition: verify_nbtree.c:49
#define TransactionIdIsValid(xid)
Definition: transam.h:41
uint16 * ii_ExclusionStrats
Definition: execnodes.h:166
MemoryContext targetcontext
Definition: verify_nbtree.c:82
Pointer Page
Definition: bufpage.h:78

◆ bt_check_level_from_leftmost()

static BtreeLevel bt_check_level_from_leftmost ( BtreeCheckState state,
BtreeLevel  level 
)
static

Definition at line 657 of file verify_nbtree.c.

References Assert, bt_recheck_sibling_links(), bt_target_page_check(), BTPageOpaqueData::btpo, BTPageOpaqueData::btpo_next, BTPageOpaqueData::btpo_prev, BTreeTupleGetDownLink(), CHECK_FOR_INTERRUPTS, DEBUG1, elog, ereport, errcode(), errdetail_internal(), errmsg(), ERROR, IndexTupleSize, InvalidBlockNumber, InvalidBtreeLevel, BtreeLevel::istruerootlevel, BtreeLevel::leftmost, BTPageOpaqueData::level, BtreeLevel::level, BtreeCheckState::lowkey, MemoryContextAlloc(), MemoryContextReset(), MemoryContextSwitchTo(), P_FIRSTDATAKEY, P_HIKEY, P_IGNORE, P_ISDELETED, P_ISLEAF, P_ISROOT, P_LEFTMOST, P_NONE, P_RIGHTMOST, PageGetItem, PageGetItemIdCareful(), PageGetLSN, PageGetSpecialPointer, palloc_btree_page(), pfree(), BtreeCheckState::previncompletesplit, BtreeCheckState::prevrightlink, BtreeCheckState::readonly, BtreeCheckState::rel, RelationGetRelationName, BtreeCheckState::target, BtreeCheckState::targetblock, BtreeCheckState::targetcontext, and BtreeCheckState::targetlsn.

Referenced by bt_check_every_level().

658 {
659  /* State to establish early, concerning entire level */
660  BTPageOpaque opaque;
661  MemoryContext oldcontext;
662  BtreeLevel nextleveldown;
663 
664  /* Variables for iterating across level using right links */
665  BlockNumber leftcurrent = P_NONE;
666  BlockNumber current = level.leftmost;
667 
668  /* Initialize return state */
669  nextleveldown.leftmost = InvalidBlockNumber;
670  nextleveldown.level = InvalidBtreeLevel;
671  nextleveldown.istruerootlevel = false;
672 
673  /* Use page-level context for duration of this call */
674  oldcontext = MemoryContextSwitchTo(state->targetcontext);
675 
676  elog(DEBUG1, "verifying level %u%s", level.level,
677  level.istruerootlevel ?
678  " (true root level)" : level.level == 0 ? " (leaf level)" : "");
679 
681  state->previncompletesplit = false;
682 
683  do
684  {
685  /* Don't rely on CHECK_FOR_INTERRUPTS() calls at lower level */
687 
688  /* Initialize state for this iteration */
689  state->targetblock = current;
690  state->target = palloc_btree_page(state, state->targetblock);
691  state->targetlsn = PageGetLSN(state->target);
692 
693  opaque = (BTPageOpaque) PageGetSpecialPointer(state->target);
694 
695  if (P_IGNORE(opaque))
696  {
697  /*
698  * Since there cannot be a concurrent VACUUM operation in readonly
699  * mode, and since a page has no links within other pages
700  * (siblings and parent) once it is marked fully deleted, it
701  * should be impossible to land on a fully deleted page in
702  * readonly mode. See bt_child_check() for further details.
703  *
704  * The bt_child_check() P_ISDELETED() check is repeated here so
705  * that pages that are only reachable through sibling links get
706  * checked.
707  */
708  if (state->readonly && P_ISDELETED(opaque))
709  ereport(ERROR,
710  (errcode(ERRCODE_INDEX_CORRUPTED),
711  errmsg("downlink or sibling link points to deleted block in index \"%s\"",
712  RelationGetRelationName(state->rel)),
713  errdetail_internal("Block=%u left block=%u left link from block=%u.",
714  current, leftcurrent, opaque->btpo_prev)));
715 
716  if (P_RIGHTMOST(opaque))
717  ereport(ERROR,
718  (errcode(ERRCODE_INDEX_CORRUPTED),
719  errmsg("block %u fell off the end of index \"%s\"",
720  current, RelationGetRelationName(state->rel))));
721  else
722  ereport(DEBUG1,
723  (errcode(ERRCODE_NO_DATA),
724  errmsg("block %u of index \"%s\" ignored",
725  current, RelationGetRelationName(state->rel))));
726  goto nextpage;
727  }
728  else if (nextleveldown.leftmost == InvalidBlockNumber)
729  {
730  /*
731  * A concurrent page split could make the caller supplied leftmost
732  * block no longer contain the leftmost page, or no longer be the
733  * true root, but where that isn't possible due to heavyweight
734  * locking, check that the first valid page meets caller's
735  * expectations.
736  */
737  if (state->readonly)
738  {
739  if (!P_LEFTMOST(opaque))
740  ereport(ERROR,
741  (errcode(ERRCODE_INDEX_CORRUPTED),
742  errmsg("block %u is not leftmost in index \"%s\"",
743  current, RelationGetRelationName(state->rel))));
744 
745  if (level.istruerootlevel && !P_ISROOT(opaque))
746  ereport(ERROR,
747  (errcode(ERRCODE_INDEX_CORRUPTED),
748  errmsg("block %u is not true root in index \"%s\"",
749  current, RelationGetRelationName(state->rel))));
750  }
751 
752  /*
753  * Before beginning any non-trivial examination of level, prepare
754  * state for next bt_check_level_from_leftmost() invocation for
755  * the next level for the next level down (if any).
756  *
757  * There should be at least one non-ignorable page per level,
758  * unless this is the leaf level, which is assumed by caller to be
759  * final level.
760  */
761  if (!P_ISLEAF(opaque))
762  {
763  IndexTuple itup;
764  ItemId itemid;
765 
766  /* Internal page -- downlink gets leftmost on next level */
767  itemid = PageGetItemIdCareful(state, state->targetblock,
768  state->target,
769  P_FIRSTDATAKEY(opaque));
770  itup = (IndexTuple) PageGetItem(state->target, itemid);
771  nextleveldown.leftmost = BTreeTupleGetDownLink(itup);
772  nextleveldown.level = opaque->btpo.level - 1;
773  }
774  else
775  {
776  /*
777  * Leaf page -- final level caller must process.
778  *
779  * Note that this could also be the root page, if there has
780  * been no root page split yet.
781  */
782  nextleveldown.leftmost = P_NONE;
783  nextleveldown.level = InvalidBtreeLevel;
784  }
785 
786  /*
787  * Finished setting up state for this call/level. Control will
788  * never end up back here in any future loop iteration for this
789  * level.
790  */
791  }
792 
793  /* Sibling links should be in mutual agreement */
794  if (opaque->btpo_prev != leftcurrent)
795  bt_recheck_sibling_links(state, opaque->btpo_prev, leftcurrent);
796 
797  /* Check level, which must be valid for non-ignorable page */
798  if (level.level != opaque->btpo.level)
799  ereport(ERROR,
800  (errcode(ERRCODE_INDEX_CORRUPTED),
801  errmsg("leftmost down link for level points to block in index \"%s\" whose level is not one level down",
802  RelationGetRelationName(state->rel)),
803  errdetail_internal("Block pointed to=%u expected level=%u level in pointed to block=%u.",
804  current, level.level, opaque->btpo.level)));
805 
806  /* Verify invariants for page */
807  bt_target_page_check(state);
808 
809 nextpage:
810 
811  /* Try to detect circular links */
812  if (current == leftcurrent || current == opaque->btpo_prev)
813  ereport(ERROR,
814  (errcode(ERRCODE_INDEX_CORRUPTED),
815  errmsg("circular link chain found in block %u of index \"%s\"",
816  current, RelationGetRelationName(state->rel))));
817 
818  leftcurrent = current;
819  current = opaque->btpo_next;
820 
821  if (state->lowkey)
822  {
823  Assert(state->readonly);
824  pfree(state->lowkey);
825  state->lowkey = NULL;
826  }
827 
828  /*
829  * Copy current target high key as the low key of right sibling.
830  * Allocate memory in upper level context, so it would be cleared
831  * after reset of target context.
832  *
833  * We only need the low key in corner cases of checking child high
834  * keys. We use high key only when incomplete split on the child level
835  * falls to the boundary of pages on the target level. See
836  * bt_child_highkey_check() for details. So, typically we won't end
837  * up doing anything with low key, but it's simpler for general case
838  * high key verification to always have it available.
839  *
840  * The correctness of managing low key in the case of concurrent
841  * splits wasn't investigated yet. Thankfully we only need low key
842  * for readonly verification and concurrent splits won't happen.
843  */
844  if (state->readonly && !P_RIGHTMOST(opaque))
845  {
846  IndexTuple itup;
847  ItemId itemid;
848 
849  itemid = PageGetItemIdCareful(state, state->targetblock,
850  state->target, P_HIKEY);
851  itup = (IndexTuple) PageGetItem(state->target, itemid);
852 
853  state->lowkey = MemoryContextAlloc(oldcontext, IndexTupleSize(itup));
854  memcpy(state->lowkey, itup, IndexTupleSize(itup));
855  }
856 
857  /* Free page and associated memory for this iteration */
859  }
860  while (current != P_NONE);
861 
862  if (state->lowkey)
863  {
864  Assert(state->readonly);
865  pfree(state->lowkey);
866  state->lowkey = NULL;
867  }
868 
869  /* Don't change context for caller */
870  MemoryContextSwitchTo(oldcontext);
871 
872  return nextleveldown;
873 }
BlockNumber targetblock
Definition: verify_nbtree.c:93
BlockNumber btpo_next
Definition: nbtree.h:59
#define DEBUG1
Definition: elog.h:25
#define P_IGNORE(opaque)
Definition: nbtree.h:219
static Page palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum)
uint32 level
#define P_FIRSTDATAKEY(opaque)
Definition: nbtree.h:244
union BTPageOpaqueData::@45 btpo
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:109
#define P_NONE
Definition: nbtree.h:206
static BlockNumber BTreeTupleGetDownLink(IndexTuple pivot)
Definition: nbtree.h:424
int errcode(int sqlerrcode)
Definition: elog.c:610
void MemoryContextReset(MemoryContext context)
Definition: mcxt.c:137
uint32 BlockNumber
Definition: block.h:31
BTPageOpaqueData * BTPageOpaque
Definition: nbtree.h:69
int errdetail_internal(const char *fmt,...)
Definition: elog.c:981
XLogRecPtr targetlsn
Definition: verify_nbtree.c:95
void pfree(void *pointer)
Definition: mcxt.c:1057
#define ERROR
Definition: elog.h:43
static void bt_recheck_sibling_links(BtreeCheckState *state, BlockNumber btpo_prev_from_target, BlockNumber leftcurrent)
BlockNumber btpo_prev
Definition: nbtree.h:58
BlockNumber leftmost
IndexTupleData * IndexTuple
Definition: itup.h:53
#define RelationGetRelationName(relation)
Definition: rel.h:490
#define P_LEFTMOST(opaque)
Definition: nbtree.h:212
#define P_ISDELETED(opaque)
Definition: nbtree.h:216
#define P_ISROOT(opaque)
Definition: nbtree.h:215
uint32 level
Definition: nbtree.h:62
#define ereport(elevel,...)
Definition: elog.h:144
#define Assert(condition)
Definition: c.h:746
static void bt_target_page_check(BtreeCheckState *state)
#define PageGetSpecialPointer(page)
Definition: bufpage.h:326
#define InvalidBlockNumber
Definition: block.h:33
#define PageGetLSN(page)
Definition: bufpage.h:366
IndexTuple lowkey
#define P_HIKEY
Definition: nbtree.h:242
int errmsg(const char *fmt,...)
Definition: elog.c:821
static ItemId PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block, Page page, OffsetNumber offset)
void * MemoryContextAlloc(MemoryContext context, Size size)
Definition: mcxt.c:797
#define elog(elevel,...)
Definition: elog.h:214
bool istruerootlevel
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:99
#define InvalidBtreeLevel
Definition: verify_nbtree.c:49
MemoryContext targetcontext
Definition: verify_nbtree.c:82
#define P_RIGHTMOST(opaque)
Definition: nbtree.h:213
BlockNumber prevrightlink
#define PageGetItem(page, itemId)
Definition: bufpage.h:340
#define IndexTupleSize(itup)
Definition: itup.h:71
#define P_ISLEAF(opaque)
Definition: nbtree.h:214

◆ bt_child_check()

static void bt_child_check ( BtreeCheckState state,
BTScanInsert  targetkey,
OffsetNumber  downlinkoffnum 
)
static

Definition at line 2077 of file verify_nbtree.c.

References Assert, bt_child_highkey_check(), BTPageOpaqueData::btpo, BTreeTupleGetDownLink(), ereport, errcode(), errdetail_internal(), errmsg(), ERROR, invariant_l_nontarget_offset(), BTPageOpaqueData::level, offset_is_negative_infinity(), OffsetNumberNext, P_FIRSTDATAKEY, P_ISDELETED, PageGetItem, PageGetItemIdCareful(), PageGetMaxOffsetNumber, PageGetSpecialPointer, palloc_btree_page(), pfree(), BtreeCheckState::readonly, BtreeCheckState::rel, RelationGetRelationName, BtreeCheckState::target, BtreeCheckState::targetblock, and BtreeCheckState::targetlsn.

Referenced by bt_target_page_check().

2079 {
2080  ItemId itemid;
2081  IndexTuple itup;
2082  BlockNumber childblock;
2083  OffsetNumber offset;
2084  OffsetNumber maxoffset;
2085  Page child;
2086  BTPageOpaque copaque;
2087  BTPageOpaque topaque;
2088 
2089  itemid = PageGetItemIdCareful(state, state->targetblock,
2090  state->target, downlinkoffnum);
2091  itup = (IndexTuple) PageGetItem(state->target, itemid);
2092  childblock = BTreeTupleGetDownLink(itup);
2093 
2094  /*
2095  * Caller must have ShareLock on target relation, because of
2096  * considerations around page deletion by VACUUM.
2097  *
2098  * NB: In general, page deletion deletes the right sibling's downlink, not
2099  * the downlink of the page being deleted; the deleted page's downlink is
2100  * reused for its sibling. The key space is thereby consolidated between
2101  * the deleted page and its right sibling. (We cannot delete a parent
2102  * page's rightmost child unless it is the last child page, and we intend
2103  * to also delete the parent itself.)
2104  *
2105  * If this verification happened without a ShareLock, the following race
2106  * condition could cause false positives:
2107  *
2108  * In general, concurrent page deletion might occur, including deletion of
2109  * the left sibling of the child page that is examined here. If such a
2110  * page deletion were to occur, closely followed by an insertion into the
2111  * newly expanded key space of the child, a window for the false positive
2112  * opens up: the stale parent/target downlink originally followed to get
2113  * to the child legitimately ceases to be a lower bound on all items in
2114  * the page, since the key space was concurrently expanded "left".
2115  * (Insertion followed the "new" downlink for the child, not our now-stale
2116  * downlink, which was concurrently physically removed in target/parent as
2117  * part of deletion's first phase.)
2118  *
2119  * While we use various techniques elsewhere to perform cross-page
2120  * verification for !readonly callers, a similar trick seems difficult
2121  * here. The tricks used by bt_recheck_sibling_links and by
2122  * bt_right_page_check_scankey both involve verification of a same-level,
2123  * cross-sibling invariant. Cross-level invariants are far more squishy,
2124  * though. The nbtree REDO routines do not actually couple buffer locks
2125  * across levels during page splits, so making any cross-level check work
2126  * reliably in !readonly mode may be impossible.
2127  */
2128  Assert(state->readonly);
2129 
2130  /*
2131  * Verify child page has the downlink key from target page (its parent) as
2132  * a lower bound; downlink must be strictly less than all keys on the
2133  * page.
2134  *
2135  * Check all items, rather than checking just the first and trusting that
2136  * the operator class obeys the transitive law.
2137  */
2138  topaque = (BTPageOpaque) PageGetSpecialPointer(state->target);
2139  child = palloc_btree_page(state, childblock);
2140  copaque = (BTPageOpaque) PageGetSpecialPointer(child);
2141  maxoffset = PageGetMaxOffsetNumber(child);
2142 
2143  /*
2144  * Since we've already loaded the child block, combine this check with
2145  * check for downlink connectivity.
2146  */
2147  bt_child_highkey_check(state, downlinkoffnum,
2148  child, topaque->btpo.level);
2149 
2150  /*
2151  * Since there cannot be a concurrent VACUUM operation in readonly mode,
2152  * and since a page has no links within other pages (siblings and parent)
2153  * once it is marked fully deleted, it should be impossible to land on a
2154  * fully deleted page.
2155  *
2156  * It does not quite make sense to enforce that the page cannot even be
2157  * half-dead, despite the fact the downlink is modified at the same stage
2158  * that the child leaf page is marked half-dead. That's incorrect because
2159  * there may occasionally be multiple downlinks from a chain of pages
2160  * undergoing deletion, where multiple successive calls are made to
2161  * _bt_unlink_halfdead_page() by VACUUM before it can finally safely mark
2162  * the leaf page as fully dead. While _bt_mark_page_halfdead() usually
2163  * removes the downlink to the leaf page that is marked half-dead, that's
2164  * not guaranteed, so it's possible we'll land on a half-dead page with a
2165  * downlink due to an interrupted multi-level page deletion.
2166  *
2167  * We go ahead with our checks if the child page is half-dead. It's safe
2168  * to do so because we do not test the child's high key, so it does not
2169  * matter that the original high key will have been replaced by a dummy
2170  * truncated high key within _bt_mark_page_halfdead(). All other page
2171  * items are left intact on a half-dead page, so there is still something
2172  * to test.
2173  */
2174  if (P_ISDELETED(copaque))
2175  ereport(ERROR,
2176  (errcode(ERRCODE_INDEX_CORRUPTED),
2177  errmsg("downlink to deleted page found in index \"%s\"",
2178  RelationGetRelationName(state->rel)),
2179  errdetail_internal("Parent block=%u child block=%u parent page lsn=%X/%X.",
2180  state->targetblock, childblock,
2181  (uint32) (state->targetlsn >> 32),
2182  (uint32) state->targetlsn)));
2183 
2184  for (offset = P_FIRSTDATAKEY(copaque);
2185  offset <= maxoffset;
2186  offset = OffsetNumberNext(offset))
2187  {
2188  /*
2189  * Skip comparison of target page key against "negative infinity"
2190  * item, if any. Checking it would indicate that it's not a strict
2191  * lower bound, but that's only because of the hard-coding for
2192  * negative infinity items within _bt_compare().
2193  *
2194  * If nbtree didn't truncate negative infinity tuples during internal
2195  * page splits then we'd expect child's negative infinity key to be
2196  * equal to the scankey/downlink from target/parent (it would be a
2197  * "low key" in this hypothetical scenario, and so it would still need
2198  * to be treated as a special case here).
2199  *
2200  * Negative infinity items can be thought of as a strict lower bound
2201  * that works transitively, with the last non-negative-infinity pivot
2202  * followed during a descent from the root as its "true" strict lower
2203  * bound. Only a small number of negative infinity items are truly
2204  * negative infinity; those that are the first items of leftmost
2205  * internal pages. In more general terms, a negative infinity item is
2206  * only negative infinity with respect to the subtree that the page is
2207  * at the root of.
2208  *
2209  * See also: bt_rootdescend(), which can even detect transitive
2210  * inconsistencies on cousin leaf pages.
2211  */
2212  if (offset_is_negative_infinity(copaque, offset))
2213  continue;
2214 
2215  if (!invariant_l_nontarget_offset(state, targetkey, childblock, child,
2216  offset))
2217  ereport(ERROR,
2218  (errcode(ERRCODE_INDEX_CORRUPTED),
2219  errmsg("down-link lower bound invariant violated for index \"%s\"",
2220  RelationGetRelationName(state->rel)),
2221  errdetail_internal("Parent block=%u child index tid=(%u,%u) parent page lsn=%X/%X.",
2222  state->targetblock, childblock, offset,
2223  (uint32) (state->targetlsn >> 32),
2224  (uint32) state->targetlsn)));
2225  }
2226 
2227  pfree(child);
2228 }
BlockNumber targetblock
Definition: verify_nbtree.c:93
static Page palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum)
#define P_FIRSTDATAKEY(opaque)
Definition: nbtree.h:244
union BTPageOpaqueData::@45 btpo
static BlockNumber BTreeTupleGetDownLink(IndexTuple pivot)
Definition: nbtree.h:424
int errcode(int sqlerrcode)
Definition: elog.c:610
uint32 BlockNumber
Definition: block.h:31
#define PageGetMaxOffsetNumber(page)
Definition: bufpage.h:357
BTPageOpaqueData * BTPageOpaque
Definition: nbtree.h:69
int errdetail_internal(const char *fmt,...)
Definition: elog.c:981
uint16 OffsetNumber
Definition: off.h:24
XLogRecPtr targetlsn
Definition: verify_nbtree.c:95
void pfree(void *pointer)
Definition: mcxt.c:1057
#define ERROR
Definition: elog.h:43
IndexTupleData * IndexTuple
Definition: itup.h:53
#define RelationGetRelationName(relation)
Definition: rel.h:490
unsigned int uint32
Definition: c.h:375
#define P_ISDELETED(opaque)
Definition: nbtree.h:216
uint32 level
Definition: nbtree.h:62
static bool invariant_l_nontarget_offset(BtreeCheckState *state, BTScanInsert key, BlockNumber nontargetblock, Page nontarget, OffsetNumber upperbound)
#define ereport(elevel,...)
Definition: elog.h:144
static void bt_child_highkey_check(BtreeCheckState *state, OffsetNumber target_downlinkoffnum, Page loaded_child, uint32 target_level)
#define Assert(condition)
Definition: c.h:746
#define OffsetNumberNext(offsetNumber)
Definition: off.h:52
#define PageGetSpecialPointer(page)
Definition: bufpage.h:326
int errmsg(const char *fmt,...)
Definition: elog.c:821
static ItemId PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block, Page page, OffsetNumber offset)
static bool offset_is_negative_infinity(BTPageOpaque opaque, OffsetNumber offset)
#define PageGetItem(page, itemId)
Definition: bufpage.h:340
Pointer Page
Definition: bufpage.h:78

◆ bt_child_highkey_check()

static void bt_child_highkey_check ( BtreeCheckState state,
OffsetNumber  target_downlinkoffnum,
Page  loaded_child,
uint32  target_level 
)
static

Definition at line 1828 of file verify_nbtree.c.

References BlockNumberIsValid, bt_downlink_missing_check(), bt_pivot_tuple_identical(), BTPageOpaqueData::btpo, BTPageOpaqueData::btpo_next, BTPageOpaqueData::btpo_prev, BTreeTupleGetDownLink(), ereport, errcode(), errdetail_internal(), errmsg(), ERROR, BtreeCheckState::heapkeyspace, InvalidBlockNumber, BTPageOpaqueData::level, BtreeCheckState::lowkey, offset_is_negative_infinity(), OffsetNumberIsValid, OffsetNumberNext, P_HIKEY, P_IGNORE, P_INCOMPLETE_SPLIT, P_LEFTMOST, P_NONE, P_RIGHTMOST, PageGetItem, PageGetItemIdCareful(), PageGetMaxOffsetNumber, PageGetSpecialPointer, palloc_btree_page(), pfree(), BtreeCheckState::previncompletesplit, BtreeCheckState::prevrightlink, BtreeCheckState::rel, RelationGetRelationName, BtreeCheckState::target, BtreeCheckState::targetblock, and BtreeCheckState::targetlsn.

Referenced by bt_child_check(), and bt_target_page_check().

1832 {
1833  BlockNumber blkno = state->prevrightlink;
1834  Page page;
1835  BTPageOpaque opaque;
1836  bool rightsplit = state->previncompletesplit;
1837  bool first = true;
1838  ItemId itemid;
1839  IndexTuple itup;
1840  BlockNumber downlink;
1841 
1842  if (OffsetNumberIsValid(target_downlinkoffnum))
1843  {
1844  itemid = PageGetItemIdCareful(state, state->targetblock,
1845  state->target, target_downlinkoffnum);
1846  itup = (IndexTuple) PageGetItem(state->target, itemid);
1847  downlink = BTreeTupleGetDownLink(itup);
1848  }
1849  else
1850  {
1851  downlink = P_NONE;
1852  }
1853 
1854  /*
1855  * If no previous rightlink is memorized for current level just below
1856  * target page's level, we are about to start from the leftmost page. We
1857  * can't follow rightlinks from previous page, because there is no
1858  * previous page. But we still can match high key.
1859  *
1860  * So we initialize variables for the loop above like there is previous
1861  * page referencing current child. Also we imply previous page to not
1862  * have incomplete split flag, that would make us require downlink for
1863  * current child. That's correct, because leftmost page on the level
1864  * should always have parent downlink.
1865  */
1866  if (!BlockNumberIsValid(blkno))
1867  {
1868  blkno = downlink;
1869  rightsplit = false;
1870  }
1871 
1872  /* Move to the right on the child level */
1873  while (true)
1874  {
1875  /*
1876  * Did we traverse the whole tree level and this is check for pages to
1877  * the right of rightmost downlink?
1878  */
1879  if (blkno == P_NONE && downlink == P_NONE)
1880  {
1882  state->previncompletesplit = false;
1883  return;
1884  }
1885 
1886  /* Did we traverse the whole tree level and don't find next downlink? */
1887  if (blkno == P_NONE)
1888  ereport(ERROR,
1889  (errcode(ERRCODE_INDEX_CORRUPTED),
1890  errmsg("can't traverse from downlink %u to downlink %u of index \"%s\"",
1891  state->prevrightlink, downlink,
1892  RelationGetRelationName(state->rel))));
1893 
1894  /* Load page contents */
1895  if (blkno == downlink && loaded_child)
1896  page = loaded_child;
1897  else
1898  page = palloc_btree_page(state, blkno);
1899 
1900  opaque = (BTPageOpaque) PageGetSpecialPointer(page);
1901 
1902  /* The first page we visit at the level should be leftmost */
1903  if (first && !BlockNumberIsValid(state->prevrightlink) && !P_LEFTMOST(opaque))
1904  ereport(ERROR,
1905  (errcode(ERRCODE_INDEX_CORRUPTED),
1906  errmsg("the first child of leftmost target page is not leftmost of its level in index \"%s\"",
1907  RelationGetRelationName(state->rel)),
1908  errdetail_internal("Target block=%u child block=%u target page lsn=%X/%X.",
1909  state->targetblock, blkno,
1910  (uint32) (state->targetlsn >> 32),
1911  (uint32) state->targetlsn)));
1912 
1913  /* Check level for non-ignorable page */
1914  if (!P_IGNORE(opaque) && opaque->btpo.level != target_level - 1)
1915  ereport(ERROR,
1916  (errcode(ERRCODE_INDEX_CORRUPTED),
1917  errmsg("block found while following rightlinks from child of index \"%s\" has invalid level",
1918  RelationGetRelationName(state->rel)),
1919  errdetail_internal("Block pointed to=%u expected level=%u level in pointed to block=%u.",
1920  blkno, target_level - 1, opaque->btpo.level)));
1921 
1922  /* Try to detect circular links */
1923  if ((!first && blkno == state->prevrightlink) || blkno == opaque->btpo_prev)
1924  ereport(ERROR,
1925  (errcode(ERRCODE_INDEX_CORRUPTED),
1926  errmsg("circular link chain found in block %u of index \"%s\"",
1927  blkno, RelationGetRelationName(state->rel))));
1928 
1929  if (blkno != downlink && !P_IGNORE(opaque))
1930  {
1931  /* blkno probably has missing parent downlink */
1932  bt_downlink_missing_check(state, rightsplit, blkno, page);
1933  }
1934 
1935  rightsplit = P_INCOMPLETE_SPLIT(opaque);
1936 
1937  /*
1938  * If we visit page with high key, check that it is equal to the
1939  * target key next to corresponding downlink.
1940  */
1941  if (!rightsplit && !P_RIGHTMOST(opaque))
1942  {
1943  BTPageOpaque topaque;
1944  IndexTuple highkey;
1945  OffsetNumber pivotkey_offset;
1946 
1947  /* Get high key */
1948  itemid = PageGetItemIdCareful(state, blkno, page, P_HIKEY);
1949  highkey = (IndexTuple) PageGetItem(page, itemid);
1950 
1951  /*
1952  * There might be two situations when we examine high key. If
1953  * current child page is referenced by given target downlink, we
1954  * should look to the next offset number for matching key from
1955  * target page.
1956  *
1957  * Alternatively, we're following rightlinks somewhere in the
1958  * middle between page referenced by previous target's downlink
1959  * and the page referenced by current target's downlink. If
1960  * current child page hasn't incomplete split flag set, then its
1961  * high key should match to the target's key of current offset
1962  * number. This happens when a previous call here (to
1963  * bt_child_highkey_check()) found an incomplete split, and we
1964  * reach a right sibling page without a downlink -- the right
1965  * sibling page's high key still needs to be matched to a
1966  * separator key on the parent/target level.
1967  *
1968  * Don't apply OffsetNumberNext() to target_downlinkoffnum when we
1969  * already had to step right on the child level. Our traversal of
1970  * the child level must try to move in perfect lockstep behind (to
1971  * the left of) the target/parent level traversal.
1972  */
1973  if (blkno == downlink)
1974  pivotkey_offset = OffsetNumberNext(target_downlinkoffnum);
1975  else
1976  pivotkey_offset = target_downlinkoffnum;
1977 
1978  topaque = (BTPageOpaque) PageGetSpecialPointer(state->target);
1979 
1980  if (!offset_is_negative_infinity(topaque, pivotkey_offset))
1981  {
1982  /*
1983  * If we're looking for the next pivot tuple in target page,
1984  * but there is no more pivot tuples, then we should match to
1985  * high key instead.
1986  */
1987  if (pivotkey_offset > PageGetMaxOffsetNumber(state->target))
1988  {
1989  if (P_RIGHTMOST(topaque))
1990  ereport(ERROR,
1991  (errcode(ERRCODE_INDEX_CORRUPTED),
1992  errmsg("child high key is greater than rightmost pivot key on target level in index \"%s\"",
1993  RelationGetRelationName(state->rel)),
1994  errdetail_internal("Target block=%u child block=%u target page lsn=%X/%X.",
1995  state->targetblock, blkno,
1996  (uint32) (state->targetlsn >> 32),
1997  (uint32) state->targetlsn)));
1998  pivotkey_offset = P_HIKEY;
1999  }
2000  itemid = PageGetItemIdCareful(state, state->targetblock,
2001  state->target, pivotkey_offset);
2002  itup = (IndexTuple) PageGetItem(state->target, itemid);
2003  }
2004  else
2005  {
2006  /*
2007  * We cannot try to match child's high key to a negative
2008  * infinity key in target, since there is nothing to compare.
2009  * However, it's still possible to match child's high key
2010  * outside of target page. The reason why we're are is that
2011  * bt_child_highkey_check() was previously called for the
2012  * cousin page of 'loaded_child', which is incomplete split.
2013  * So, now we traverse to the right of that cousin page and
2014  * current child level page under consideration still belongs
2015  * to the subtree of target's left sibling. Thus, we need to
2016  * match child's high key to it's left uncle page high key.
2017  * Thankfully we saved it, it's called a "low key" of target
2018  * page.
2019  */
2020  if (!state->lowkey)
2021  ereport(ERROR,
2022  (errcode(ERRCODE_INDEX_CORRUPTED),
2023  errmsg("can't find left sibling high key in index \"%s\"",
2024  RelationGetRelationName(state->rel)),
2025  errdetail_internal("Target block=%u child block=%u target page lsn=%X/%X.",
2026  state->targetblock, blkno,
2027  (uint32) (state->targetlsn >> 32),
2028  (uint32) state->targetlsn)));
2029  itup = state->lowkey;
2030  }
2031 
2032  if (!bt_pivot_tuple_identical(state->heapkeyspace, highkey, itup))
2033  {
2034  ereport(ERROR,
2035  (errcode(ERRCODE_INDEX_CORRUPTED),
2036  errmsg("mismatch between parent key and child high key in index \"%s\"",
2037  RelationGetRelationName(state->rel)),
2038  errdetail_internal("Target block=%u child block=%u target page lsn=%X/%X.",
2039  state->targetblock, blkno,
2040  (uint32) (state->targetlsn >> 32),
2041  (uint32) state->targetlsn)));
2042  }
2043  }
2044 
2045  /* Exit if we already found next downlink */
2046  if (blkno == downlink)
2047  {
2048  state->prevrightlink = opaque->btpo_next;
2049  state->previncompletesplit = rightsplit;
2050  return;
2051  }
2052 
2053  /* Traverse to the next page using rightlink */
2054  blkno = opaque->btpo_next;
2055 
2056  /* Free page contents if it's allocated by us */
2057  if (page != loaded_child)
2058  pfree(page);
2059  first = false;
2060  }
2061 }
BlockNumber targetblock
Definition: verify_nbtree.c:93
BlockNumber btpo_next
Definition: nbtree.h:59
#define P_IGNORE(opaque)
Definition: nbtree.h:219
static Page palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum)
static bool bt_pivot_tuple_identical(bool heapkeyspace, IndexTuple itup1, IndexTuple itup2)
union BTPageOpaqueData::@45 btpo
#define P_NONE
Definition: nbtree.h:206
static BlockNumber BTreeTupleGetDownLink(IndexTuple pivot)
Definition: nbtree.h:424
int errcode(int sqlerrcode)
Definition: elog.c:610
uint32 BlockNumber
Definition: block.h:31
#define P_INCOMPLETE_SPLIT(opaque)
Definition: nbtree.h:221
#define PageGetMaxOffsetNumber(page)
Definition: bufpage.h:357
BTPageOpaqueData * BTPageOpaque
Definition: nbtree.h:69
static void bt_downlink_missing_check(BtreeCheckState *state, bool rightsplit, BlockNumber targetblock, Page target)
int errdetail_internal(const char *fmt,...)
Definition: elog.c:981
uint16 OffsetNumber
Definition: off.h:24
XLogRecPtr targetlsn
Definition: verify_nbtree.c:95
void pfree(void *pointer)
Definition: mcxt.c:1057
#define ERROR
Definition: elog.h:43
BlockNumber btpo_prev
Definition: nbtree.h:58
IndexTupleData * IndexTuple
Definition: itup.h:53
#define RelationGetRelationName(relation)
Definition: rel.h:490
#define P_LEFTMOST(opaque)
Definition: nbtree.h:212
unsigned int uint32
Definition: c.h:375
uint32 level
Definition: nbtree.h:62
#define ereport(elevel,...)
Definition: elog.h:144
#define BlockNumberIsValid(blockNumber)
Definition: block.h:70
#define OffsetNumberNext(offsetNumber)
Definition: off.h:52
#define PageGetSpecialPointer(page)
Definition: bufpage.h:326
#define InvalidBlockNumber
Definition: block.h:33
IndexTuple lowkey
#define P_HIKEY
Definition: nbtree.h:242
int errmsg(const char *fmt,...)
Definition: elog.c:821
static ItemId PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block, Page page, OffsetNumber offset)
#define OffsetNumberIsValid(offsetNumber)
Definition: off.h:39
static bool offset_is_negative_infinity(BTPageOpaque opaque, OffsetNumber offset)
#define P_RIGHTMOST(opaque)
Definition: nbtree.h:213
BlockNumber prevrightlink
#define PageGetItem(page, itemId)
Definition: bufpage.h:340
Pointer Page
Definition: bufpage.h:78

◆ bt_downlink_missing_check()

static void bt_downlink_missing_check ( BtreeCheckState state,
bool  rightsplit,
BlockNumber  targetblock,
Page  target 
)
static

Definition at line 2244 of file verify_nbtree.c.

References Assert, BTPageOpaqueData::btpo, BTPageOpaqueData::btpo_prev, BTreeTupleGetDownLink(), BTreeTupleGetTopParent(), CHECK_FOR_INTERRUPTS, DEBUG1, elog, ereport, errcode(), errdetail_internal(), errmsg(), errmsg_internal(), ERROR, BTPageOpaqueData::level, P_FIRSTDATAKEY, P_HIKEY, P_IGNORE, P_ISDELETED, P_ISHALFDEAD, P_ISLEAF, P_ISROOT, P_RIGHTMOST, PageGetItem, PageGetItemIdCareful(), PageGetLSN, PageGetSpecialPointer, palloc_btree_page(), pfree(), BtreeCheckState::readonly, BtreeCheckState::rel, and RelationGetRelationName.

Referenced by bt_child_highkey_check().

2246 {
2248  ItemId itemid;
2249  IndexTuple itup;
2250  Page child;
2251  BTPageOpaque copaque;
2252  uint32 level;
2253  BlockNumber childblk;
2254  XLogRecPtr pagelsn;
2255 
2256  Assert(state->readonly);
2257  Assert(!P_IGNORE(opaque));
2258 
2259  /* No next level up with downlinks to fingerprint from the true root */
2260  if (P_ISROOT(opaque))
2261  return;
2262 
2263  pagelsn = PageGetLSN(page);
2264 
2265  /*
2266  * Incomplete (interrupted) page splits can account for the lack of a
2267  * downlink. Some inserting transaction should eventually complete the
2268  * page split in passing, when it notices that the left sibling page is
2269  * P_INCOMPLETE_SPLIT().
2270  *
2271  * In general, VACUUM is not prepared for there to be no downlink to a
2272  * page that it deletes. This is the main reason why the lack of a
2273  * downlink can be reported as corruption here. It's not obvious that an
2274  * invalid missing downlink can result in wrong answers to queries,
2275  * though, since index scans that land on the child may end up
2276  * consistently moving right. The handling of concurrent page splits (and
2277  * page deletions) within _bt_moveright() cannot distinguish
2278  * inconsistencies that last for a moment from inconsistencies that are
2279  * permanent and irrecoverable.
2280  *
2281  * VACUUM isn't even prepared to delete pages that have no downlink due to
2282  * an incomplete page split, but it can detect and reason about that case
2283  * by design, so it shouldn't be taken to indicate corruption. See
2284  * _bt_pagedel() for full details.
2285  */
2286  if (rightsplit)
2287  {
2288  ereport(DEBUG1,
2289  (errcode(ERRCODE_NO_DATA),
2290  errmsg("harmless interrupted page split detected in index %s",
2291  RelationGetRelationName(state->rel)),
2292  errdetail_internal("Block=%u level=%u left sibling=%u page lsn=%X/%X.",
2293  blkno, opaque->btpo.level,
2294  opaque->btpo_prev,
2295  (uint32) (pagelsn >> 32),
2296  (uint32) pagelsn)));
2297  return;
2298  }
2299 
2300  /*
2301  * Page under check is probably the "top parent" of a multi-level page
2302  * deletion. We'll need to descend the subtree to make sure that
2303  * descendant pages are consistent with that, though.
2304  *
2305  * If the page (which must be non-ignorable) is a leaf page, then clearly
2306  * it can't be the top parent. The lack of a downlink is probably a
2307  * symptom of a broad problem that could just as easily cause
2308  * inconsistencies anywhere else.
2309  */
2310  if (P_ISLEAF(opaque))
2311  ereport(ERROR,
2312  (errcode(ERRCODE_INDEX_CORRUPTED),
2313  errmsg("leaf index block lacks downlink in index \"%s\"",
2314  RelationGetRelationName(state->rel)),
2315  errdetail_internal("Block=%u page lsn=%X/%X.",
2316  blkno,
2317  (uint32) (pagelsn >> 32),
2318  (uint32) pagelsn)));
2319 
2320  /* Descend from the given page, which is an internal page */
2321  elog(DEBUG1, "checking for interrupted multi-level deletion due to missing downlink in index \"%s\"",
2322  RelationGetRelationName(state->rel));
2323 
2324  level = opaque->btpo.level;
2325  itemid = PageGetItemIdCareful(state, blkno, page, P_FIRSTDATAKEY(opaque));
2326  itup = (IndexTuple) PageGetItem(page, itemid);
2327  childblk = BTreeTupleGetDownLink(itup);
2328  for (;;)
2329  {
2331 
2332  child = palloc_btree_page(state, childblk);
2333  copaque = (BTPageOpaque) PageGetSpecialPointer(child);
2334 
2335  if (P_ISLEAF(copaque))
2336  break;
2337 
2338  /* Do an extra sanity check in passing on internal pages */
2339  if (copaque->btpo.level != level - 1)
2340  ereport(ERROR,
2341  (errcode(ERRCODE_INDEX_CORRUPTED),
2342  errmsg_internal("downlink points to block in index \"%s\" whose level is not one level down",
2343  RelationGetRelationName(state->rel)),
2344  errdetail_internal("Top parent/under check block=%u block pointed to=%u expected level=%u level in pointed to block=%u.",
2345  blkno, childblk,
2346  level - 1, copaque->btpo.level)));
2347 
2348  level = copaque->btpo.level;
2349  itemid = PageGetItemIdCareful(state, childblk, child,
2350  P_FIRSTDATAKEY(copaque));
2351  itup = (IndexTuple) PageGetItem(child, itemid);
2352  childblk = BTreeTupleGetDownLink(itup);
2353  /* Be slightly more pro-active in freeing this memory, just in case */
2354  pfree(child);
2355  }
2356 
2357  /*
2358  * Since there cannot be a concurrent VACUUM operation in readonly mode,
2359  * and since a page has no links within other pages (siblings and parent)
2360  * once it is marked fully deleted, it should be impossible to land on a
2361  * fully deleted page. See bt_child_check() for further details.
2362  *
2363  * The bt_child_check() P_ISDELETED() check is repeated here because
2364  * bt_child_check() does not visit pages reachable through negative
2365  * infinity items. Besides, bt_child_check() is unwilling to descend
2366  * multiple levels. (The similar bt_child_check() P_ISDELETED() check
2367  * within bt_check_level_from_leftmost() won't reach the page either,
2368  * since the leaf's live siblings should have their sibling links updated
2369  * to bypass the deletion target page when it is marked fully dead.)
2370  *
2371  * If this error is raised, it might be due to a previous multi-level page
2372  * deletion that failed to realize that it wasn't yet safe to mark the
2373  * leaf page as fully dead. A "dangling downlink" will still remain when
2374  * this happens. The fact that the dangling downlink's page (the leaf's
2375  * parent/ancestor page) lacked a downlink is incidental.
2376  */
2377  if (P_ISDELETED(copaque))
2378  ereport(ERROR,
2379  (errcode(ERRCODE_INDEX_CORRUPTED),
2380  errmsg_internal("downlink to deleted leaf page found in index \"%s\"",
2381  RelationGetRelationName(state->rel)),
2382  errdetail_internal("Top parent/target block=%u leaf block=%u top parent/under check lsn=%X/%X.",
2383  blkno, childblk,
2384  (uint32) (pagelsn >> 32),
2385  (uint32) pagelsn)));
2386 
2387  /*
2388  * Iff leaf page is half-dead, its high key top parent link should point
2389  * to what VACUUM considered to be the top parent page at the instant it
2390  * was interrupted. Provided the high key link actually points to the
2391  * page under check, the missing downlink we detected is consistent with
2392  * there having been an interrupted multi-level page deletion. This means
2393  * that the subtree with the page under check at its root (a page deletion
2394  * chain) is in a consistent state, enabling VACUUM to resume deleting the
2395  * entire chain the next time it encounters the half-dead leaf page.
2396  */
2397  if (P_ISHALFDEAD(copaque) && !P_RIGHTMOST(copaque))
2398  {
2399  itemid = PageGetItemIdCareful(state, childblk, child, P_HIKEY);
2400  itup = (IndexTuple) PageGetItem(child, itemid);
2401  if (BTreeTupleGetTopParent(itup) == blkno)
2402  return;
2403  }
2404 
2405  ereport(ERROR,
2406  (errcode(ERRCODE_INDEX_CORRUPTED),
2407  errmsg("internal index block lacks downlink in index \"%s\"",
2408  RelationGetRelationName(state->rel)),
2409  errdetail_internal("Block=%u level=%u page lsn=%X/%X.",
2410  blkno, opaque->btpo.level,
2411  (uint32) (pagelsn >> 32),
2412  (uint32) pagelsn)));
2413 }
#define DEBUG1
Definition: elog.h:25
#define P_IGNORE(opaque)
Definition: nbtree.h:219
static Page palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum)
#define P_FIRSTDATAKEY(opaque)
Definition: nbtree.h:244
union BTPageOpaqueData::@45 btpo
static BlockNumber BTreeTupleGetDownLink(IndexTuple pivot)
Definition: nbtree.h:424
int errcode(int sqlerrcode)
Definition: elog.c:610
uint32 BlockNumber
Definition: block.h:31
BTPageOpaqueData * BTPageOpaque
Definition: nbtree.h:69
int errdetail_internal(const char *fmt,...)
Definition: elog.c:981
void pfree(void *pointer)
Definition: mcxt.c:1057
#define P_ISHALFDEAD(opaque)
Definition: nbtree.h:218
#define ERROR
Definition: elog.h:43
BlockNumber btpo_prev
Definition: nbtree.h:58
IndexTupleData * IndexTuple
Definition: itup.h:53
#define RelationGetRelationName(relation)
Definition: rel.h:490
unsigned int uint32
Definition: c.h:375
#define P_ISDELETED(opaque)
Definition: nbtree.h:216
#define P_ISROOT(opaque)
Definition: nbtree.h:215
uint32 level
Definition: nbtree.h:62
#define ereport(elevel,...)
Definition: elog.h:144
int errmsg_internal(const char *fmt,...)
Definition: elog.c:908
uint64 XLogRecPtr
Definition: xlogdefs.h:21
#define Assert(condition)
Definition: c.h:746
#define PageGetSpecialPointer(page)
Definition: bufpage.h:326
#define PageGetLSN(page)
Definition: bufpage.h:366
#define P_HIKEY
Definition: nbtree.h:242
int errmsg(const char *fmt,...)
Definition: elog.c:821
static ItemId PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block, Page page, OffsetNumber offset)
#define elog(elevel,...)
Definition: elog.h:214
static BlockNumber BTreeTupleGetTopParent(IndexTuple leafhikey)
Definition: nbtree.h:488
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:99
#define P_RIGHTMOST(opaque)
Definition: nbtree.h:213
#define PageGetItem(page, itemId)
Definition: bufpage.h:340
Pointer Page
Definition: bufpage.h:78
#define P_ISLEAF(opaque)
Definition: nbtree.h:214

◆ bt_index_check()

Datum bt_index_check ( PG_FUNCTION_ARGS  )

Definition at line 201 of file verify_nbtree.c.

References bt_index_check_internal(), BtreeCheckState::heapallindexed, PG_GETARG_BOOL, PG_GETARG_OID, PG_NARGS, and PG_RETURN_VOID.

202 {
203  Oid indrelid = PG_GETARG_OID(0);
204  bool heapallindexed = false;
205 
206  if (PG_NARGS() == 2)
207  heapallindexed = PG_GETARG_BOOL(1);
208 
209  bt_index_check_internal(indrelid, false, heapallindexed, false);
210 
211  PG_RETURN_VOID();
212 }
#define PG_GETARG_BOOL(n)
Definition: fmgr.h:274
unsigned int Oid
Definition: postgres_ext.h:31
static void bt_index_check_internal(Oid indrelid, bool parentcheck, bool heapallindexed, bool rootdescend)
#define PG_GETARG_OID(n)
Definition: fmgr.h:275
#define PG_RETURN_VOID()
Definition: fmgr.h:348
#define PG_NARGS()
Definition: fmgr.h:203

◆ bt_index_check_internal()

static void bt_index_check_internal ( Oid  indrelid,
bool  parentcheck,
bool  heapallindexed,
bool  rootdescend 
)
static

Definition at line 244 of file verify_nbtree.c.

References _bt_allequalimage(), _bt_metaversion(), AccessShareLock, bt_check_every_level(), btree_index_checkable(), btree_index_mainfork_expected(), ereport, errcode(), ERRCODE_UNDEFINED_TABLE, errmsg(), ERROR, BtreeCheckState::heapkeyspace, BtreeCheckState::heaprel, index_close(), index_open(), IndexGetRelation(), MAIN_FORKNUM, OidIsValid, RelationData::rd_smgr, RelationGetRelationName, RelationOpenSmgr, ShareLock, smgrexists(), table_close(), and table_open().

Referenced by bt_index_check(), and bt_index_parent_check().

246 {
247  Oid heapid;
248  Relation indrel;
249  Relation heaprel;
250  LOCKMODE lockmode;
251 
252  if (parentcheck)
253  lockmode = ShareLock;
254  else
255  lockmode = AccessShareLock;
256 
257  /*
258  * We must lock table before index to avoid deadlocks. However, if the
259  * passed indrelid isn't an index then IndexGetRelation() will fail.
260  * Rather than emitting a not-very-helpful error message, postpone
261  * complaining, expecting that the is-it-an-index test below will fail.
262  *
263  * In hot standby mode this will raise an error when parentcheck is true.
264  */
265  heapid = IndexGetRelation(indrelid, true);
266  if (OidIsValid(heapid))
267  heaprel = table_open(heapid, lockmode);
268  else
269  heaprel = NULL;
270 
271  /*
272  * Open the target index relations separately (like relation_openrv(), but
273  * with heap relation locked first to prevent deadlocking). In hot
274  * standby mode this will raise an error when parentcheck is true.
275  *
276  * There is no need for the usual indcheckxmin usability horizon test
277  * here, even in the heapallindexed case, because index undergoing
278  * verification only needs to have entries for a new transaction snapshot.
279  * (If this is a parentcheck verification, there is no question about
280  * committed or recently dead heap tuples lacking index entries due to
281  * concurrent activity.)
282  */
283  indrel = index_open(indrelid, lockmode);
284 
285  /*
286  * Since we did the IndexGetRelation call above without any lock, it's
287  * barely possible that a race against an index drop/recreation could have
288  * netted us the wrong table.
289  */
290  if (heaprel == NULL || heapid != IndexGetRelation(indrelid, false))
291  ereport(ERROR,
293  errmsg("could not open parent table of index %s",
294  RelationGetRelationName(indrel))));
295 
296  /* Relation suitable for checking as B-Tree? */
297  btree_index_checkable(indrel);
298 
299  if (btree_index_mainfork_expected(indrel))
300  {
301  bool heapkeyspace,
302  allequalimage;
303 
304  RelationOpenSmgr(indrel);
305  if (!smgrexists(indrel->rd_smgr, MAIN_FORKNUM))
306  ereport(ERROR,
307  (errcode(ERRCODE_INDEX_CORRUPTED),
308  errmsg("index \"%s\" lacks a main relation fork",
309  RelationGetRelationName(indrel))));
310 
311  /* Extract metadata from metapage, and sanitize it in passing */
312  _bt_metaversion(indrel, &heapkeyspace, &allequalimage);
313  if (allequalimage && !heapkeyspace)
314  ereport(ERROR,
315  (errcode(ERRCODE_INDEX_CORRUPTED),
316  errmsg("index \"%s\" metapage has equalimage field set on unsupported nbtree version",
317  RelationGetRelationName(indrel))));
318  if (allequalimage && !_bt_allequalimage(indrel, false))
319  ereport(ERROR,
320  (errcode(ERRCODE_INDEX_CORRUPTED),
321  errmsg("index \"%s\" metapage incorrectly indicates that deduplication is safe",
322  RelationGetRelationName(indrel))));
323 
324  /* Check index, possibly against table it is an index on */
325  bt_check_every_level(indrel, heaprel, heapkeyspace, parentcheck,
326  heapallindexed, rootdescend);
327  }
328 
329  /*
330  * Release locks early. That's ok here because nothing in the called
331  * routines will trigger shared cache invalidations to be sent, so we can
332  * relax the usual pattern of only releasing locks after commit.
333  */
334  index_close(indrel, lockmode);
335  if (heaprel)
336  table_close(heaprel, lockmode);
337 }
Oid IndexGetRelation(Oid indexId, bool missing_ok)
Definition: index.c:3401
static bool btree_index_mainfork_expected(Relation rel)
void table_close(Relation relation, LOCKMODE lockmode)
Definition: table.c:167
#define ERRCODE_UNDEFINED_TABLE
Definition: pgbench.c:74
static void btree_index_checkable(Relation rel)
int LOCKMODE
Definition: lockdefs.h:26
struct SMgrRelationData * rd_smgr
Definition: rel.h:57
#define AccessShareLock
Definition: lockdefs.h:36
int errcode(int sqlerrcode)
Definition: elog.c:610
bool smgrexists(SMgrRelation reln, ForkNumber forknum)
Definition: smgr.c:248
unsigned int Oid
Definition: postgres_ext.h:31
#define OidIsValid(objectId)
Definition: c.h:652
#define RelationOpenSmgr(relation)
Definition: rel.h:513
#define ERROR
Definition: elog.h:43
static void bt_check_every_level(Relation rel, Relation heaprel, bool heapkeyspace, bool readonly, bool heapallindexed, bool rootdescend)
#define RelationGetRelationName(relation)
Definition: rel.h:490
void _bt_metaversion(Relation rel, bool *heapkeyspace, bool *allequalimage)
Definition: nbtpage.c:668
#define ereport(elevel,...)
Definition: elog.h:144
void index_close(Relation relation, LOCKMODE lockmode)
Definition: indexam.c:158
int errmsg(const char *fmt,...)
Definition: elog.c:821
#define ShareLock
Definition: lockdefs.h:41
Relation table_open(Oid relationId, LOCKMODE lockmode)
Definition: table.c:39
bool _bt_allequalimage(Relation rel, bool debugmessage)
Definition: nbtutils.c:2691
Relation index_open(Oid relationId, LOCKMODE lockmode)
Definition: indexam.c:132

◆ bt_index_parent_check()

Datum bt_index_parent_check ( PG_FUNCTION_ARGS  )

Definition at line 224 of file verify_nbtree.c.

References bt_index_check_internal(), BtreeCheckState::heapallindexed, PG_GETARG_BOOL, PG_GETARG_OID, PG_NARGS, PG_RETURN_VOID, and BtreeCheckState::rootdescend.

225 {
226  Oid indrelid = PG_GETARG_OID(0);
227  bool heapallindexed = false;
228  bool rootdescend = false;
229 
230  if (PG_NARGS() >= 2)
231  heapallindexed = PG_GETARG_BOOL(1);
232  if (PG_NARGS() == 3)
233  rootdescend = PG_GETARG_BOOL(2);
234 
235  bt_index_check_internal(indrelid, true, heapallindexed, rootdescend);
236 
237  PG_RETURN_VOID();
238 }
#define PG_GETARG_BOOL(n)
Definition: fmgr.h:274
unsigned int Oid
Definition: postgres_ext.h:31
static void bt_index_check_internal(Oid indrelid, bool parentcheck, bool heapallindexed, bool rootdescend)
#define PG_GETARG_OID(n)
Definition: fmgr.h:275
#define PG_RETURN_VOID()
Definition: fmgr.h:348
#define PG_NARGS()
Definition: fmgr.h:203

◆ bt_mkscankey_pivotsearch()

static BTScanInsert bt_mkscankey_pivotsearch ( Relation  rel,
IndexTuple  itup 
)
inlinestatic

Definition at line 3100 of file verify_nbtree.c.

References _bt_mkscankey(), and BTScanInsertData::pivotsearch.

Referenced by bt_right_page_check_scankey(), and bt_target_page_check().

3101 {
3102  BTScanInsert skey;
3103 
3104  skey = _bt_mkscankey(rel, itup);
3105  skey->pivotsearch = true;
3106 
3107  return skey;
3108 }
BTScanInsert _bt_mkscankey(Relation rel, IndexTuple itup)
Definition: nbtutils.c:90
bool pivotsearch
Definition: nbtree.h:663

◆ bt_normalize_tuple()

static IndexTuple bt_normalize_tuple ( BtreeCheckState state,
IndexTuple  itup 
)
static

Definition at line 2539 of file verify_nbtree.c.

References Assert, BTreeTupleIsPivot(), BTreeTupleIsPosting(), DatumGetPointer, ereport, errcode(), errmsg(), ERROR, i, index_form_tuple(), index_getattr, INDEX_MAX_KEYS, IndexTupleHasVarwidths, ItemPointerGetBlockNumber, ItemPointerGetOffsetNumber, TupleDescData::natts, pfree(), PG_DETOAST_DATUM, PointerGetDatum, BtreeCheckState::rel, RelationGetDescr, RelationGetRelationName, IndexTupleData::t_tid, TupleDescAttr, VARATT_IS_COMPRESSED, and VARATT_IS_EXTERNAL.

Referenced by bt_target_page_check(), and bt_tuple_present_callback().

2540 {
2541  TupleDesc tupleDescriptor = RelationGetDescr(state->rel);
2542  Datum normalized[INDEX_MAX_KEYS];
2543  bool isnull[INDEX_MAX_KEYS];
2544  bool toast_free[INDEX_MAX_KEYS];
2545  bool formnewtup = false;
2546  IndexTuple reformed;
2547  int i;
2548 
2549  /* Caller should only pass "logical" non-pivot tuples here */
2550  Assert(!BTreeTupleIsPosting(itup) && !BTreeTupleIsPivot(itup));
2551 
2552  /* Easy case: It's immediately clear that tuple has no varlena datums */
2553  if (!IndexTupleHasVarwidths(itup))
2554  return itup;
2555 
2556  for (i = 0; i < tupleDescriptor->natts; i++)
2557  {
2558  Form_pg_attribute att;
2559 
2560  att = TupleDescAttr(tupleDescriptor, i);
2561 
2562  /* Assume untoasted/already normalized datum initially */
2563  toast_free[i] = false;
2564  normalized[i] = index_getattr(itup, att->attnum,
2565  tupleDescriptor,
2566  &isnull[i]);
2567  if (att->attbyval || att->attlen != -1 || isnull[i])
2568  continue;
2569 
2570  /*
2571  * Callers always pass a tuple that could safely be inserted into the
2572  * index without further processing, so an external varlena header
2573  * should never be encountered here
2574  */
2575  if (VARATT_IS_EXTERNAL(DatumGetPointer(normalized[i])))
2576  ereport(ERROR,
2577  (errcode(ERRCODE_INDEX_CORRUPTED),
2578  errmsg("external varlena datum in tuple that references heap row (%u,%u) in index \"%s\"",
2579  ItemPointerGetBlockNumber(&(itup->t_tid)),
2581  RelationGetRelationName(state->rel))));
2582  else if (VARATT_IS_COMPRESSED(DatumGetPointer(normalized[i])))
2583  {
2584  formnewtup = true;
2585  normalized[i] = PointerGetDatum(PG_DETOAST_DATUM(normalized[i]));
2586  toast_free[i] = true;
2587  }
2588  }
2589 
2590  /* Easier case: Tuple has varlena datums, none of which are compressed */
2591  if (!formnewtup)
2592  return itup;
2593 
2594  /*
2595  * Hard case: Tuple had compressed varlena datums that necessitate
2596  * creating normalized version of the tuple from uncompressed input datums
2597  * (normalized input datums). This is rather naive, but shouldn't be
2598  * necessary too often.
2599  *
2600  * Note that we rely on deterministic index_form_tuple() TOAST compression
2601  * of normalized input.
2602  */
2603  reformed = index_form_tuple(tupleDescriptor, normalized, isnull);
2604  reformed->t_tid = itup->t_tid;
2605 
2606  /* Cannot leak memory here */
2607  for (i = 0; i < tupleDescriptor->natts; i++)
2608  if (toast_free[i])
2609  pfree(DatumGetPointer(normalized[i]));
2610 
2611  return reformed;
2612 }
#define VARATT_IS_COMPRESSED(PTR)
Definition: postgres.h:312
static bool BTreeTupleIsPivot(IndexTuple itup)
Definition: nbtree.h:348
#define RelationGetDescr(relation)
Definition: rel.h:482
#define PointerGetDatum(X)
Definition: postgres.h:556
#define TupleDescAttr(tupdesc, i)
Definition: tupdesc.h:92
ItemPointerData t_tid
Definition: itup.h:37
int errcode(int sqlerrcode)
Definition: elog.c:610
#define VARATT_IS_EXTERNAL(PTR)
Definition: postgres.h:313
IndexTuple index_form_tuple(TupleDesc tupleDescriptor, Datum *values, bool *isnull)
Definition: indextuple.c:47
void pfree(void *pointer)
Definition: mcxt.c:1057
#define ERROR
Definition: elog.h:43
#define RelationGetRelationName(relation)
Definition: rel.h:490
FormData_pg_attribute * Form_pg_attribute
Definition: pg_attribute.h:193
uintptr_t Datum
Definition: postgres.h:367
#define ereport(elevel,...)
Definition: elog.h:144
static bool BTreeTupleIsPosting(IndexTuple itup)
Definition: nbtree.h:360
#define Assert(condition)
Definition: c.h:746
#define INDEX_MAX_KEYS
#define index_getattr(tup, attnum, tupleDesc, isnull)
Definition: itup.h:100
#define ItemPointerGetOffsetNumber(pointer)
Definition: itemptr.h:117
#define IndexTupleHasVarwidths(itup)
Definition: itup.h:73
#define DatumGetPointer(X)
Definition: postgres.h:549
int errmsg(const char *fmt,...)
Definition: elog.c:821
int i
#define PG_DETOAST_DATUM(datum)
Definition: fmgr.h:240
#define ItemPointerGetBlockNumber(pointer)
Definition: itemptr.h:98

◆ bt_pivot_tuple_identical()

static bool bt_pivot_tuple_identical ( bool  heapkeyspace,
IndexTuple  itup1,
IndexTuple  itup2 
)
static

Definition at line 1755 of file verify_nbtree.c.

References IndexTupleSize, ItemPointerData::ip_posid, offsetof, IndexTupleData::t_info, and IndexTupleData::t_tid.

Referenced by bt_child_highkey_check().

1756 {
1757  if (IndexTupleSize(itup1) != IndexTupleSize(itup2))
1758  return false;
1759 
1760  if (heapkeyspace)
1761  {
1762  /*
1763  * Offset number will contain important information in heapkeyspace
1764  * indexes: the number of attributes left in the pivot tuple following
1765  * suffix truncation. Don't skip over it (compare it too).
1766  */
1767  if (memcmp(&itup1->t_tid.ip_posid, &itup2->t_tid.ip_posid,
1768  IndexTupleSize(itup1) -
1769  offsetof(ItemPointerData, ip_posid)) != 0)
1770  return false;
1771  }
1772  else
1773  {
1774  /*
1775  * Cannot rely on offset number field having consistent value across
1776  * levels on pg_upgrade'd !heapkeyspace indexes. Compare contents of
1777  * tuple starting from just after item pointer (i.e. after block
1778  * number and offset number).
1779  */
1780  if (memcmp(&itup1->t_info, &itup2->t_info,
1781  IndexTupleSize(itup1) -
1782  offsetof(IndexTupleData, t_info)) != 0)
1783  return false;
1784  }
1785 
1786  return true;
1787 }
ItemPointerData t_tid
Definition: itup.h:37
unsigned short t_info
Definition: itup.h:49
OffsetNumber ip_posid
Definition: itemptr.h:39
#define offsetof(type, field)
Definition: c.h:669
#define IndexTupleSize(itup)
Definition: itup.h:71

◆ bt_posting_plain_tuple()

static IndexTuple bt_posting_plain_tuple ( IndexTuple  itup,
int  n 
)
inlinestatic

Definition at line 2629 of file verify_nbtree.c.

References _bt_form_posting(), Assert, BTreeTupleGetPostingN(), and BTreeTupleIsPosting().

Referenced by bt_target_page_check().

2630 {
2631  Assert(BTreeTupleIsPosting(itup));
2632 
2633  /* Returns non-posting-list tuple */
2634  return _bt_form_posting(itup, BTreeTupleGetPostingN(itup, n), 1);
2635 }
IndexTuple _bt_form_posting(IndexTuple base, ItemPointer htids, int nhtids)
Definition: nbtdedup.c:616
static ItemPointer BTreeTupleGetPostingN(IndexTuple posting, int n)
Definition: nbtree.h:412
static bool BTreeTupleIsPosting(IndexTuple itup)
Definition: nbtree.h:360
#define Assert(condition)
Definition: c.h:746

◆ bt_recheck_sibling_links()

static void bt_recheck_sibling_links ( BtreeCheckState state,
BlockNumber  btpo_prev_from_target,
BlockNumber  leftcurrent 
)
static

Definition at line 911 of file verify_nbtree.c.

References _bt_checkpage(), BT_READ, BTPageOpaqueData::btpo_next, BTPageOpaqueData::btpo_prev, BufferGetPage, BufferIsValid, BtreeCheckState::checkstrategy, DEBUG1, ereport, errcode(), errdetail_internal(), errmsg(), ERROR, InvalidBlockNumber, InvalidBuffer, LockBuffer(), MAIN_FORKNUM, P_ISDELETED, PageGetSpecialPointer, RBM_NORMAL, ReadBufferExtended(), BtreeCheckState::readonly, BtreeCheckState::rel, RelationGetRelationName, BtreeCheckState::targetblock, and UnlockReleaseBuffer().

Referenced by bt_check_level_from_leftmost().

914 {
915  if (!state->readonly)
916  {
917  Buffer lbuf;
918  Buffer newtargetbuf;
919  Page page;
920  BTPageOpaque opaque;
921  BlockNumber newtargetblock;
922 
923  /* Couple locks in the usual order for nbtree: Left to right */
924  lbuf = ReadBufferExtended(state->rel, MAIN_FORKNUM, leftcurrent,
925  RBM_NORMAL, state->checkstrategy);
926  LockBuffer(lbuf, BT_READ);
927  _bt_checkpage(state->rel, lbuf);
928  page = BufferGetPage(lbuf);
929  opaque = (BTPageOpaque) PageGetSpecialPointer(page);
930  if (P_ISDELETED(opaque))
931  {
932  /*
933  * Cannot reason about concurrently deleted page -- the left link
934  * in the page to the right is expected to point to some other
935  * page to the left (not leftcurrent page).
936  *
937  * Note that we deliberately don't give up with a half-dead page.
938  */
939  UnlockReleaseBuffer(lbuf);
940  return;
941  }
942 
943  newtargetblock = opaque->btpo_next;
944  /* Avoid self-deadlock when newtargetblock == leftcurrent */
945  if (newtargetblock != leftcurrent)
946  {
947  newtargetbuf = ReadBufferExtended(state->rel, MAIN_FORKNUM,
948  newtargetblock, RBM_NORMAL,
949  state->checkstrategy);
950  LockBuffer(newtargetbuf, BT_READ);
951  _bt_checkpage(state->rel, newtargetbuf);
952  page = BufferGetPage(newtargetbuf);
953  opaque = (BTPageOpaque) PageGetSpecialPointer(page);
954  /* btpo_prev_from_target may have changed; update it */
955  btpo_prev_from_target = opaque->btpo_prev;
956  }
957  else
958  {
959  /*
960  * leftcurrent right sibling points back to leftcurrent block.
961  * Index is corrupt. Easiest way to handle this is to pretend
962  * that we actually read from a distinct page that has an invalid
963  * block number in its btpo_prev.
964  */
965  newtargetbuf = InvalidBuffer;
966  btpo_prev_from_target = InvalidBlockNumber;
967  }
968 
969  /*
970  * No need to check P_ISDELETED here, since new target block cannot be
971  * marked deleted as long as we hold a lock on lbuf
972  */
973  if (BufferIsValid(newtargetbuf))
974  UnlockReleaseBuffer(newtargetbuf);
975  UnlockReleaseBuffer(lbuf);
976 
977  if (btpo_prev_from_target == leftcurrent)
978  {
979  /* Report split in left sibling, not target (or new target) */
980  ereport(DEBUG1,
981  (errcode(ERRCODE_INTERNAL_ERROR),
982  errmsg("harmless concurrent page split detected in index \"%s\"",
983  RelationGetRelationName(state->rel)),
984  errdetail_internal("Block=%u new right sibling=%u original right sibling=%u.",
985  leftcurrent, newtargetblock,
986  state->targetblock)));
987  return;
988  }
989 
990  /*
991  * Index is corrupt. Make sure that we report correct target page.
992  *
993  * This could have changed in cases where there was a concurrent page
994  * split, as well as index corruption (at least in theory). Note that
995  * btpo_prev_from_target was already updated above.
996  */
997  state->targetblock = newtargetblock;
998  }
999 
1000  ereport(ERROR,
1001  (errcode(ERRCODE_INDEX_CORRUPTED),
1002  errmsg("left link/right link pair in index \"%s\" not in agreement",
1003  RelationGetRelationName(state->rel)),
1004  errdetail_internal("Block=%u left block=%u left link from block=%u.",
1005  state->targetblock, leftcurrent,
1006  btpo_prev_from_target)));
1007 }
BlockNumber targetblock
Definition: verify_nbtree.c:93
BlockNumber btpo_next
Definition: nbtree.h:59
#define DEBUG1
Definition: elog.h:25
Buffer ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum, ReadBufferMode mode, BufferAccessStrategy strategy)
Definition: bufmgr.c:654
#define InvalidBuffer
Definition: buf.h:25
int errcode(int sqlerrcode)
Definition: elog.c:610
uint32 BlockNumber
Definition: block.h:31
BufferAccessStrategy checkstrategy
Definition: verify_nbtree.c:84
BTPageOpaqueData * BTPageOpaque
Definition: nbtree.h:69
int errdetail_internal(const char *fmt,...)
Definition: elog.c:981
#define BT_READ
Definition: nbtree.h:587
void _bt_checkpage(Relation rel, Buffer buf)
Definition: nbtpage.c:726
void UnlockReleaseBuffer(Buffer buffer)
Definition: bufmgr.c:3536
#define ERROR
Definition: elog.h:43
BlockNumber btpo_prev
Definition: nbtree.h:58
#define RelationGetRelationName(relation)
Definition: rel.h:490
#define BufferGetPage(buffer)
Definition: bufmgr.h:169
#define P_ISDELETED(opaque)
Definition: nbtree.h:216
void LockBuffer(Buffer buffer, int mode)
Definition: bufmgr.c:3752
#define ereport(elevel,...)
Definition: elog.h:144
#define PageGetSpecialPointer(page)
Definition: bufpage.h:326
#define InvalidBlockNumber
Definition: block.h:33
#define BufferIsValid(bufnum)
Definition: bufmgr.h:123
int errmsg(const char *fmt,...)
Definition: elog.c:821
int Buffer
Definition: buf.h:23
Pointer Page
Definition: bufpage.h:78

◆ bt_right_page_check_scankey()

static BTScanInsert bt_right_page_check_scankey ( BtreeCheckState state)
static

Definition at line 1553 of file verify_nbtree.c.

References bt_mkscankey_pivotsearch(), BTPageOpaqueData::btpo, BTPageOpaqueData::btpo_next, CHECK_FOR_INTERRUPTS, DEBUG1, ereport, errcode(), errdetail_internal(), errmsg(), BTPageOpaqueData::level, OffsetNumberNext, P_FIRSTDATAKEY, P_IGNORE, P_ISLEAF, P_RIGHTMOST, PageGetItem, PageGetItemIdCareful(), PageGetMaxOffsetNumber, PageGetSpecialPointer, palloc_btree_page(), pfree(), BtreeCheckState::rel, RelationGetRelationName, and BtreeCheckState::target.

Referenced by bt_target_page_check().

1554 {
1555  BTPageOpaque opaque;
1556  ItemId rightitem;
1557  IndexTuple firstitup;
1558  BlockNumber targetnext;
1559  Page rightpage;
1560  OffsetNumber nline;
1561 
1562  /* Determine target's next block number */
1563  opaque = (BTPageOpaque) PageGetSpecialPointer(state->target);
1564 
1565  /* If target is already rightmost, no right sibling; nothing to do here */
1566  if (P_RIGHTMOST(opaque))
1567  return NULL;
1568 
1569  /*
1570  * General notes on concurrent page splits and page deletion:
1571  *
1572  * Routines like _bt_search() don't require *any* page split interlock
1573  * when descending the tree, including something very light like a buffer
1574  * pin. That's why it's okay that we don't either. This avoidance of any
1575  * need to "couple" buffer locks is the raison d' etre of the Lehman & Yao
1576  * algorithm, in fact.
1577  *
1578  * That leaves deletion. A deleted page won't actually be recycled by
1579  * VACUUM early enough for us to fail to at least follow its right link
1580  * (or left link, or downlink) and find its sibling, because recycling
1581  * does not occur until no possible index scan could land on the page.
1582  * Index scans can follow links with nothing more than their snapshot as
1583  * an interlock and be sure of at least that much. (See page
1584  * recycling/"visible to everyone" notes in nbtree README.)
1585  *
1586  * Furthermore, it's okay if we follow a rightlink and find a half-dead or
1587  * dead (ignorable) page one or more times. There will either be a
1588  * further right link to follow that leads to a live page before too long
1589  * (before passing by parent's rightmost child), or we will find the end
1590  * of the entire level instead (possible when parent page is itself the
1591  * rightmost on its level).
1592  */
1593  targetnext = opaque->btpo_next;
1594  for (;;)
1595  {
1597 
1598  rightpage = palloc_btree_page(state, targetnext);
1599  opaque = (BTPageOpaque) PageGetSpecialPointer(rightpage);
1600 
1601  if (!P_IGNORE(opaque) || P_RIGHTMOST(opaque))
1602  break;
1603 
1604  /* We landed on a deleted page, so step right to find a live page */
1605  targetnext = opaque->btpo_next;
1606  ereport(DEBUG1,
1607  (errcode(ERRCODE_NO_DATA),
1608  errmsg("level %u leftmost page of index \"%s\" was found deleted or half dead",
1609  opaque->btpo.level, RelationGetRelationName(state->rel)),
1610  errdetail_internal("Deleted page found when building scankey from right sibling.")));
1611 
1612  /* Be slightly more pro-active in freeing this memory, just in case */
1613  pfree(rightpage);
1614  }
1615 
1616  /*
1617  * No ShareLock held case -- why it's safe to proceed.
1618  *
1619  * Problem:
1620  *
1621  * We must avoid false positive reports of corruption when caller treats
1622  * item returned here as an upper bound on target's last item. In
1623  * general, false positives are disallowed. Avoiding them here when
1624  * caller is !readonly is subtle.
1625  *
1626  * A concurrent page deletion by VACUUM of the target page can result in
1627  * the insertion of items on to this right sibling page that would
1628  * previously have been inserted on our target page. There might have
1629  * been insertions that followed the target's downlink after it was made
1630  * to point to right sibling instead of target by page deletion's first
1631  * phase. The inserters insert items that would belong on target page.
1632  * This race is very tight, but it's possible. This is our only problem.
1633  *
1634  * Non-problems:
1635  *
1636  * We are not hindered by a concurrent page split of the target; we'll
1637  * never land on the second half of the page anyway. A concurrent split
1638  * of the right page will also not matter, because the first data item
1639  * remains the same within the left half, which we'll reliably land on. If
1640  * we had to skip over ignorable/deleted pages, it cannot matter because
1641  * their key space has already been atomically merged with the first
1642  * non-ignorable page we eventually find (doesn't matter whether the page
1643  * we eventually find is a true sibling or a cousin of target, which we go
1644  * into below).
1645  *
1646  * Solution:
1647  *
1648  * Caller knows that it should reverify that target is not ignorable
1649  * (half-dead or deleted) when cross-page sibling item comparison appears
1650  * to indicate corruption (invariant fails). This detects the single race
1651  * condition that exists for caller. This is correct because the
1652  * continued existence of target block as non-ignorable (not half-dead or
1653  * deleted) implies that target page was not merged into from the right by
1654  * deletion; the key space at or after target never moved left. Target's
1655  * parent either has the same downlink to target as before, or a <
1656  * downlink due to deletion at the left of target. Target either has the
1657  * same highkey as before, or a highkey < before when there is a page
1658  * split. (The rightmost concurrently-split-from-target-page page will
1659  * still have the same highkey as target was originally found to have,
1660  * which for our purposes is equivalent to target's highkey itself never
1661  * changing, since we reliably skip over
1662  * concurrently-split-from-target-page pages.)
1663  *
1664  * In simpler terms, we allow that the key space of the target may expand
1665  * left (the key space can move left on the left side of target only), but
1666  * the target key space cannot expand right and get ahead of us without
1667  * our detecting it. The key space of the target cannot shrink, unless it
1668  * shrinks to zero due to the deletion of the original page, our canary
1669  * condition. (To be very precise, we're a bit stricter than that because
1670  * it might just have been that the target page split and only the
1671  * original target page was deleted. We can be more strict, just not more
1672  * lax.)
1673  *
1674  * Top level tree walk caller moves on to next page (makes it the new
1675  * target) following recovery from this race. (cf. The rationale for
1676  * child/downlink verification needing a ShareLock within
1677  * bt_child_check(), where page deletion is also the main source of
1678  * trouble.)
1679  *
1680  * Note that it doesn't matter if right sibling page here is actually a
1681  * cousin page, because in order for the key space to be readjusted in a
1682  * way that causes us issues in next level up (guiding problematic
1683  * concurrent insertions to the cousin from the grandparent rather than to
1684  * the sibling from the parent), there'd have to be page deletion of
1685  * target's parent page (affecting target's parent's downlink in target's
1686  * grandparent page). Internal page deletion only occurs when there are
1687  * no child pages (they were all fully deleted), and caller is checking
1688  * that the target's parent has at least one non-deleted (so
1689  * non-ignorable) child: the target page. (Note that the first phase of
1690  * deletion atomically marks the page to be deleted half-dead/ignorable at
1691  * the same time downlink in its parent is removed, so caller will
1692  * definitely not fail to detect that this happened.)
1693  *
1694  * This trick is inspired by the method backward scans use for dealing
1695  * with concurrent page splits; concurrent page deletion is a problem that
1696  * similarly receives special consideration sometimes (it's possible that
1697  * the backwards scan will re-read its "original" block after failing to
1698  * find a right-link to it, having already moved in the opposite direction
1699  * (right/"forwards") a few times to try to locate one). Just like us,
1700  * that happens only to determine if there was a concurrent page deletion
1701  * of a reference page, and just like us if there was a page deletion of
1702  * that reference page it means we can move on from caring about the
1703  * reference page. See the nbtree README for a full description of how
1704  * that works.
1705  */
1706  nline = PageGetMaxOffsetNumber(rightpage);
1707 
1708  /*
1709  * Get first data item, if any
1710  */
1711  if (P_ISLEAF(opaque) && nline >= P_FIRSTDATAKEY(opaque))
1712  {
1713  /* Return first data item (if any) */
1714  rightitem = PageGetItemIdCareful(state, targetnext, rightpage,
1715  P_FIRSTDATAKEY(opaque));
1716  }
1717  else if (!P_ISLEAF(opaque) &&
1718  nline >= OffsetNumberNext(P_FIRSTDATAKEY(opaque)))
1719  {
1720  /*
1721  * Return first item after the internal page's "negative infinity"
1722  * item
1723  */
1724  rightitem = PageGetItemIdCareful(state, targetnext, rightpage,
1725  OffsetNumberNext(P_FIRSTDATAKEY(opaque)));
1726  }
1727  else
1728  {
1729  /*
1730  * No first item. Page is probably empty leaf page, but it's also
1731  * possible that it's an internal page with only a negative infinity
1732  * item.
1733  */
1734  ereport(DEBUG1,
1735  (errcode(ERRCODE_NO_DATA),
1736  errmsg("%s block %u of index \"%s\" has no first data item",
1737  P_ISLEAF(opaque) ? "leaf" : "internal", targetnext,
1738  RelationGetRelationName(state->rel))));
1739  return NULL;
1740  }
1741 
1742  /*
1743  * Return first real item scankey. Note that this relies on right page
1744  * memory remaining allocated.
1745  */
1746  firstitup = (IndexTuple) PageGetItem(rightpage, rightitem);
1747  return bt_mkscankey_pivotsearch(state->rel, firstitup);
1748 }
BlockNumber btpo_next
Definition: nbtree.h:59
#define DEBUG1
Definition: elog.h:25
#define P_IGNORE(opaque)
Definition: nbtree.h:219
static Page palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum)
#define P_FIRSTDATAKEY(opaque)
Definition: nbtree.h:244
union BTPageOpaqueData::@45 btpo
int errcode(int sqlerrcode)
Definition: elog.c:610
uint32 BlockNumber
Definition: block.h:31
#define PageGetMaxOffsetNumber(page)
Definition: bufpage.h:357
BTPageOpaqueData * BTPageOpaque
Definition: nbtree.h:69
int errdetail_internal(const char *fmt,...)
Definition: elog.c:981
uint16 OffsetNumber
Definition: off.h:24
void pfree(void *pointer)
Definition: mcxt.c:1057
IndexTupleData * IndexTuple
Definition: itup.h:53
#define RelationGetRelationName(relation)
Definition: rel.h:490
uint32 level
Definition: nbtree.h:62
static BTScanInsert bt_mkscankey_pivotsearch(Relation rel, IndexTuple itup)
#define ereport(elevel,...)
Definition: elog.h:144
#define OffsetNumberNext(offsetNumber)
Definition: off.h:52
#define PageGetSpecialPointer(page)
Definition: bufpage.h:326
int errmsg(const char *fmt,...)
Definition: elog.c:821
static ItemId PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block, Page page, OffsetNumber offset)
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:99
#define P_RIGHTMOST(opaque)
Definition: nbtree.h:213
#define PageGetItem(page, itemId)
Definition: bufpage.h:340
Pointer Page
Definition: bufpage.h:78
#define P_ISLEAF(opaque)
Definition: nbtree.h:214

◆ bt_rootdescend()

static bool bt_rootdescend ( BtreeCheckState state,
IndexTuple  itup 
)
static

Definition at line 2662 of file verify_nbtree.c.

References _bt_binsrch_insert(), _bt_compare(), _bt_freestack(), _bt_mkscankey(), _bt_relbuf(), _bt_search(), Assert, BTInsertStateData::bounds_valid, BT_READ, BTInsertStateData::buf, BufferGetPage, BufferIsValid, BTScanInsertData::heapkeyspace, IndexTupleSize, BTInsertStateData::itemsz, BTInsertStateData::itup, BTInsertStateData::itup_key, sort-test::key, MAXALIGN, PageGetMaxOffsetNumber, pfree(), BTInsertStateData::postingoff, BtreeCheckState::readonly, BtreeCheckState::rel, BtreeCheckState::rootdescend, and BTScanInsertData::scantid.

Referenced by bt_target_page_check().

2663 {
2664  BTScanInsert key;
2665  BTStack stack;
2666  Buffer lbuf;
2667  bool exists;
2668 
2669  key = _bt_mkscankey(state->rel, itup);
2670  Assert(key->heapkeyspace && key->scantid != NULL);
2671 
2672  /*
2673  * Search from root.
2674  *
2675  * Ideally, we would arrange to only move right within _bt_search() when
2676  * an interrupted page split is detected (i.e. when the incomplete split
2677  * bit is found to be set), but for now we accept the possibility that
2678  * that could conceal an inconsistency.
2679  */
2680  Assert(state->readonly && state->rootdescend);
2681  exists = false;
2682  stack = _bt_search(state->rel, key, &lbuf, BT_READ, NULL);
2683 
2684  if (BufferIsValid(lbuf))
2685  {
2686  BTInsertStateData insertstate;
2687  OffsetNumber offnum;
2688  Page page;
2689 
2690  insertstate.itup = itup;
2691  insertstate.itemsz = MAXALIGN(IndexTupleSize(itup));
2692  insertstate.itup_key = key;
2693  insertstate.postingoff = 0;
2694  insertstate.bounds_valid = false;
2695  insertstate.buf = lbuf;
2696 
2697  /* Get matching tuple on leaf page */
2698  offnum = _bt_binsrch_insert(state->rel, &insertstate);
2699  /* Compare first >= matching item on leaf page, if any */
2700  page = BufferGetPage(lbuf);
2701  /* Should match on first heap TID when tuple has a posting list */
2702  if (offnum <= PageGetMaxOffsetNumber(page) &&
2703  insertstate.postingoff <= 0 &&
2704  _bt_compare(state->rel, key, page, offnum) == 0)
2705  exists = true;
2706  _bt_relbuf(state->rel, lbuf);
2707  }
2708 
2709  _bt_freestack(stack);
2710  pfree(key);
2711 
2712  return exists;
2713 }
void _bt_freestack(BTStack stack)
Definition: nbtutils.c:175
bool bounds_valid
Definition: nbtree.h:696
BTScanInsert _bt_mkscankey(Relation rel, IndexTuple itup)
Definition: nbtutils.c:90
ItemPointer scantid
Definition: nbtree.h:664
#define PageGetMaxOffsetNumber(page)
Definition: bufpage.h:357
uint16 OffsetNumber
Definition: off.h:24
#define BT_READ
Definition: nbtree.h:587
void pfree(void *pointer)
Definition: mcxt.c:1057
OffsetNumber _bt_binsrch_insert(Relation rel, BTInsertState insertstate)
Definition: nbtsearch.c:447
IndexTuple itup
Definition: nbtree.h:684
int32 _bt_compare(Relation rel, BTScanInsert key, Page page, OffsetNumber offnum)
Definition: nbtsearch.c:644
#define BufferGetPage(buffer)
Definition: bufmgr.h:169
void _bt_relbuf(Relation rel, Buffer buf)
Definition: nbtpage.c:959
BTScanInsert itup_key
Definition: nbtree.h:686
#define Assert(condition)
Definition: c.h:746
bool heapkeyspace
Definition: nbtree.h:659
#define MAXALIGN(LEN)
Definition: c.h:699
#define BufferIsValid(bufnum)
Definition: bufmgr.h:123
int Buffer
Definition: buf.h:23
BTStack _bt_search(Relation rel, BTScanInsert key, Buffer *bufP, int access, Snapshot snapshot)
Definition: nbtsearch.c:101
Pointer Page
Definition: bufpage.h:78
#define IndexTupleSize(itup)
Definition: itup.h:71

◆ bt_target_page_check()

static void bt_target_page_check ( BtreeCheckState state)
static

Definition at line 1045 of file verify_nbtree.c.

References _bt_check_natts(), bloom_add_element(), bt_child_check(), bt_child_highkey_check(), bt_mkscankey_pivotsearch(), bt_normalize_tuple(), bt_posting_plain_tuple(), bt_right_page_check_scankey(), bt_rootdescend(), BTMaxItemSize, BTMaxItemSizeNoHeapTid, BTPageOpaqueData::btpo, BTreeTupleGetHeapTID(), BTreeTupleGetMaxHeapTID(), BTreeTupleGetNAtts, BTreeTupleGetNPosting(), BTreeTupleGetPointsToTID(), BTreeTupleGetPostingN(), BTreeTupleIsPosting(), CHECK_FOR_INTERRUPTS, DEBUG2, elog, ereport, errcode(), errdetail_internal(), errhint(), errmsg(), errmsg_internal(), ERROR, BtreeCheckState::filter, BtreeCheckState::heapallindexed, BtreeCheckState::heapkeyspace, BTScanInsertData::heapkeyspace, i, IndexTupleSize, InvalidOffsetNumber, invariant_g_offset(), invariant_l_offset(), invariant_leq_offset(), ItemIdGetLength, ItemIdIsDead, ItemPointerCompare(), ItemPointerCopy, ItemPointerGetBlockNumber, ItemPointerGetBlockNumberNoCheck, ItemPointerGetOffsetNumber, ItemPointerGetOffsetNumberNoCheck, BTPageOpaqueData::level, offset_is_negative_infinity(), OffsetNumberNext, P_FIRSTDATAKEY, P_HIKEY, P_IGNORE, P_ISLEAF, P_RIGHTMOST, PageGetItem, PageGetItemIdCareful(), PageGetMaxOffsetNumber, PageGetSpecialPointer, palloc_btree_page(), pfree(), psprintf(), BtreeCheckState::readonly, BtreeCheckState::rel, RelationGetRelationName, BtreeCheckState::rootdescend, BTScanInsertData::scantid, BtreeCheckState::target, BtreeCheckState::targetblock, and BtreeCheckState::targetlsn.

Referenced by bt_check_level_from_leftmost().

1046 {
1047  OffsetNumber offset;
1048  OffsetNumber max;
1049  BTPageOpaque topaque;
1050 
1051  topaque = (BTPageOpaque) PageGetSpecialPointer(state->target);
1052  max = PageGetMaxOffsetNumber(state->target);
1053 
1054  elog(DEBUG2, "verifying %u items on %s block %u", max,
1055  P_ISLEAF(topaque) ? "leaf" : "internal", state->targetblock);
1056 
1057  /*
1058  * Check the number of attributes in high key. Note, rightmost page
1059  * doesn't contain a high key, so nothing to check
1060  */
1061  if (!P_RIGHTMOST(topaque))
1062  {
1063  ItemId itemid;
1064  IndexTuple itup;
1065 
1066  /* Verify line pointer before checking tuple */
1067  itemid = PageGetItemIdCareful(state, state->targetblock,
1068  state->target, P_HIKEY);
1069  if (!_bt_check_natts(state->rel, state->heapkeyspace, state->target,
1070  P_HIKEY))
1071  {
1072  itup = (IndexTuple) PageGetItem(state->target, itemid);
1073  ereport(ERROR,
1074  (errcode(ERRCODE_INDEX_CORRUPTED),
1075  errmsg("wrong number of high key index tuple attributes in index \"%s\"",
1076  RelationGetRelationName(state->rel)),
1077  errdetail_internal("Index block=%u natts=%u block type=%s page lsn=%X/%X.",
1078  state->targetblock,
1079  BTreeTupleGetNAtts(itup, state->rel),
1080  P_ISLEAF(topaque) ? "heap" : "index",
1081  (uint32) (state->targetlsn >> 32),
1082  (uint32) state->targetlsn)));
1083  }
1084  }
1085 
1086  /*
1087  * Loop over page items, starting from first non-highkey item, not high
1088  * key (if any). Most tests are not performed for the "negative infinity"
1089  * real item (if any).
1090  */
1091  for (offset = P_FIRSTDATAKEY(topaque);
1092  offset <= max;
1093  offset = OffsetNumberNext(offset))
1094  {
1095  ItemId itemid;
1096  IndexTuple itup;
1097  size_t tupsize;
1098  BTScanInsert skey;
1099  bool lowersizelimit;
1100  ItemPointer scantid;
1101 
1103 
1104  itemid = PageGetItemIdCareful(state, state->targetblock,
1105  state->target, offset);
1106  itup = (IndexTuple) PageGetItem(state->target, itemid);
1107  tupsize = IndexTupleSize(itup);
1108 
1109  /*
1110  * lp_len should match the IndexTuple reported length exactly, since
1111  * lp_len is completely redundant in indexes, and both sources of
1112  * tuple length are MAXALIGN()'d. nbtree does not use lp_len all that
1113  * frequently, and is surprisingly tolerant of corrupt lp_len fields.
1114  */
1115  if (tupsize != ItemIdGetLength(itemid))
1116  ereport(ERROR,
1117  (errcode(ERRCODE_INDEX_CORRUPTED),
1118  errmsg("index tuple size does not equal lp_len in index \"%s\"",
1119  RelationGetRelationName(state->rel)),
1120  errdetail_internal("Index tid=(%u,%u) tuple size=%zu lp_len=%u page lsn=%X/%X.",
1121  state->targetblock, offset,
1122  tupsize, ItemIdGetLength(itemid),
1123  (uint32) (state->targetlsn >> 32),
1124  (uint32) state->targetlsn),
1125  errhint("This could be a torn page problem.")));
1126 
1127  /* Check the number of index tuple attributes */
1128  if (!_bt_check_natts(state->rel, state->heapkeyspace, state->target,
1129  offset))
1130  {
1131  ItemPointer tid;
1132  char *itid,
1133  *htid;
1134 
1135  itid = psprintf("(%u,%u)", state->targetblock, offset);
1136  tid = BTreeTupleGetPointsToTID(itup);
1137  htid = psprintf("(%u,%u)",
1140 
1141  ereport(ERROR,
1142  (errcode(ERRCODE_INDEX_CORRUPTED),
1143  errmsg("wrong number of index tuple attributes in index \"%s\"",
1144  RelationGetRelationName(state->rel)),
1145  errdetail_internal("Index tid=%s natts=%u points to %s tid=%s page lsn=%X/%X.",
1146  itid,
1147  BTreeTupleGetNAtts(itup, state->rel),
1148  P_ISLEAF(topaque) ? "heap" : "index",
1149  htid,
1150  (uint32) (state->targetlsn >> 32),
1151  (uint32) state->targetlsn)));
1152  }
1153 
1154  /*
1155  * Don't try to generate scankey using "negative infinity" item on
1156  * internal pages. They are always truncated to zero attributes.
1157  */
1158  if (offset_is_negative_infinity(topaque, offset))
1159  {
1160  /*
1161  * We don't call bt_child_check() for "negative infinity" items.
1162  * But if we're performing downlink connectivity check, we do it
1163  * for every item including "negative infinity" one.
1164  */
1165  if (!P_ISLEAF(topaque) && state->readonly)
1166  {
1167  bt_child_highkey_check(state,
1168  offset,
1169  NULL,
1170  topaque->btpo.level);
1171  }
1172  continue;
1173  }
1174 
1175  /*
1176  * Readonly callers may optionally verify that non-pivot tuples can
1177  * each be found by an independent search that starts from the root.
1178  * Note that we deliberately don't do individual searches for each
1179  * TID, since the posting list itself is validated by other checks.
1180  */
1181  if (state->rootdescend && P_ISLEAF(topaque) &&
1182  !bt_rootdescend(state, itup))
1183  {
1185  char *itid,
1186  *htid;
1187 
1188  itid = psprintf("(%u,%u)", state->targetblock, offset);
1189  htid = psprintf("(%u,%u)", ItemPointerGetBlockNumber(tid),
1191 
1192  ereport(ERROR,
1193  (errcode(ERRCODE_INDEX_CORRUPTED),
1194  errmsg("could not find tuple using search from root page in index \"%s\"",
1195  RelationGetRelationName(state->rel)),
1196  errdetail_internal("Index tid=%s points to heap tid=%s page lsn=%X/%X.",
1197  itid, htid,
1198  (uint32) (state->targetlsn >> 32),
1199  (uint32) state->targetlsn)));
1200  }
1201 
1202  /*
1203  * If tuple is a posting list tuple, make sure posting list TIDs are
1204  * in order
1205  */
1206  if (BTreeTupleIsPosting(itup))
1207  {
1208  ItemPointerData last;
1209  ItemPointer current;
1210 
1211  ItemPointerCopy(BTreeTupleGetHeapTID(itup), &last);
1212 
1213  for (int i = 1; i < BTreeTupleGetNPosting(itup); i++)
1214  {
1215 
1216  current = BTreeTupleGetPostingN(itup, i);
1217 
1218  if (ItemPointerCompare(current, &last) <= 0)
1219  {
1220  char *itid = psprintf("(%u,%u)", state->targetblock, offset);
1221 
1222  ereport(ERROR,
1223  (errcode(ERRCODE_INDEX_CORRUPTED),
1224  errmsg_internal("posting list contains misplaced TID in index \"%s\"",
1225  RelationGetRelationName(state->rel)),
1226  errdetail_internal("Index tid=%s posting list offset=%d page lsn=%X/%X.",
1227  itid, i,
1228  (uint32) (state->targetlsn >> 32),
1229  (uint32) state->targetlsn)));
1230  }
1231 
1232  ItemPointerCopy(current, &last);
1233  }
1234  }
1235 
1236  /* Build insertion scankey for current page offset */
1237  skey = bt_mkscankey_pivotsearch(state->rel, itup);
1238 
1239  /*
1240  * Make sure tuple size does not exceed the relevant BTREE_VERSION
1241  * specific limit.
1242  *
1243  * BTREE_VERSION 4 (which introduced heapkeyspace rules) requisitioned
1244  * a small amount of space from BTMaxItemSize() in order to ensure
1245  * that suffix truncation always has enough space to add an explicit
1246  * heap TID back to a tuple -- we pessimistically assume that every
1247  * newly inserted tuple will eventually need to have a heap TID
1248  * appended during a future leaf page split, when the tuple becomes
1249  * the basis of the new high key (pivot tuple) for the leaf page.
1250  *
1251  * Since the reclaimed space is reserved for that purpose, we must not
1252  * enforce the slightly lower limit when the extra space has been used
1253  * as intended. In other words, there is only a cross-version
1254  * difference in the limit on tuple size within leaf pages.
1255  *
1256  * Still, we're particular about the details within BTREE_VERSION 4
1257  * internal pages. Pivot tuples may only use the extra space for its
1258  * designated purpose. Enforce the lower limit for pivot tuples when
1259  * an explicit heap TID isn't actually present. (In all other cases
1260  * suffix truncation is guaranteed to generate a pivot tuple that's no
1261  * larger than the firstright tuple provided to it by its caller.)
1262  */
1263  lowersizelimit = skey->heapkeyspace &&
1264  (P_ISLEAF(topaque) || BTreeTupleGetHeapTID(itup) == NULL);
1265  if (tupsize > (lowersizelimit ? BTMaxItemSize(state->target) :
1266  BTMaxItemSizeNoHeapTid(state->target)))
1267  {
1269  char *itid,
1270  *htid;
1271 
1272  itid = psprintf("(%u,%u)", state->targetblock, offset);
1273  htid = psprintf("(%u,%u)",
1276 
1277  ereport(ERROR,
1278  (errcode(ERRCODE_INDEX_CORRUPTED),
1279  errmsg("index row size %zu exceeds maximum for index \"%s\"",
1280  tupsize, RelationGetRelationName(state->rel)),
1281  errdetail_internal("Index tid=%s points to %s tid=%s page lsn=%X/%X.",
1282  itid,
1283  P_ISLEAF(topaque) ? "heap" : "index",
1284  htid,
1285  (uint32) (state->targetlsn >> 32),
1286  (uint32) state->targetlsn)));
1287  }
1288 
1289  /* Fingerprint leaf page tuples (those that point to the heap) */
1290  if (state->heapallindexed && P_ISLEAF(topaque) && !ItemIdIsDead(itemid))
1291  {
1292  IndexTuple norm;
1293 
1294  if (BTreeTupleIsPosting(itup))
1295  {
1296  /* Fingerprint all elements as distinct "plain" tuples */
1297  for (int i = 0; i < BTreeTupleGetNPosting(itup); i++)
1298  {
1299  IndexTuple logtuple;
1300 
1301  logtuple = bt_posting_plain_tuple(itup, i);
1302  norm = bt_normalize_tuple(state, logtuple);
1303  bloom_add_element(state->filter, (unsigned char *) norm,
1304  IndexTupleSize(norm));
1305  /* Be tidy */
1306  if (norm != logtuple)
1307  pfree(norm);
1308  pfree(logtuple);
1309  }
1310  }
1311  else
1312  {
1313  norm = bt_normalize_tuple(state, itup);
1314  bloom_add_element(state->filter, (unsigned char *) norm,
1315  IndexTupleSize(norm));
1316  /* Be tidy */
1317  if (norm != itup)
1318  pfree(norm);
1319  }
1320  }
1321 
1322  /*
1323  * * High key check *
1324  *
1325  * If there is a high key (if this is not the rightmost page on its
1326  * entire level), check that high key actually is upper bound on all
1327  * page items. If this is a posting list tuple, we'll need to set
1328  * scantid to be highest TID in posting list.
1329  *
1330  * We prefer to check all items against high key rather than checking
1331  * just the last and trusting that the operator class obeys the
1332  * transitive law (which implies that all previous items also
1333  * respected the high key invariant if they pass the item order
1334  * check).
1335  *
1336  * Ideally, we'd compare every item in the index against every other
1337  * item in the index, and not trust opclass obedience of the
1338  * transitive law to bridge the gap between children and their
1339  * grandparents (as well as great-grandparents, and so on). We don't
1340  * go to those lengths because that would be prohibitively expensive,
1341  * and probably not markedly more effective in practice.
1342  *
1343  * On the leaf level, we check that the key is <= the highkey.
1344  * However, on non-leaf levels we check that the key is < the highkey,
1345  * because the high key is "just another separator" rather than a copy
1346  * of some existing key item; we expect it to be unique among all keys
1347  * on the same level. (Suffix truncation will sometimes produce a
1348  * leaf highkey that is an untruncated copy of the lastleft item, but
1349  * never any other item, which necessitates weakening the leaf level
1350  * check to <=.)
1351  *
1352  * Full explanation for why a highkey is never truly a copy of another
1353  * item from the same level on internal levels:
1354  *
1355  * While the new left page's high key is copied from the first offset
1356  * on the right page during an internal page split, that's not the
1357  * full story. In effect, internal pages are split in the middle of
1358  * the firstright tuple, not between the would-be lastleft and
1359  * firstright tuples: the firstright key ends up on the left side as
1360  * left's new highkey, and the firstright downlink ends up on the
1361  * right side as right's new "negative infinity" item. The negative
1362  * infinity tuple is truncated to zero attributes, so we're only left
1363  * with the downlink. In other words, the copying is just an
1364  * implementation detail of splitting in the middle of a (pivot)
1365  * tuple. (See also: "Notes About Data Representation" in the nbtree
1366  * README.)
1367  */
1368  scantid = skey->scantid;
1369  if (state->heapkeyspace && BTreeTupleIsPosting(itup))
1370  skey->scantid = BTreeTupleGetMaxHeapTID(itup);
1371 
1372  if (!P_RIGHTMOST(topaque) &&
1373  !(P_ISLEAF(topaque) ? invariant_leq_offset(state, skey, P_HIKEY) :
1374  invariant_l_offset(state, skey, P_HIKEY)))
1375  {
1377  char *itid,
1378  *htid;
1379 
1380  itid = psprintf("(%u,%u)", state->targetblock, offset);
1381  htid = psprintf("(%u,%u)",
1384 
1385  ereport(ERROR,
1386  (errcode(ERRCODE_INDEX_CORRUPTED),
1387  errmsg("high key invariant violated for index \"%s\"",
1388  RelationGetRelationName(state->rel)),
1389  errdetail_internal("Index tid=%s points to %s tid=%s page lsn=%X/%X.",
1390  itid,
1391  P_ISLEAF(topaque) ? "heap" : "index",
1392  htid,
1393  (uint32) (state->targetlsn >> 32),
1394  (uint32) state->targetlsn)));
1395  }
1396  /* Reset, in case scantid was set to (itup) posting tuple's max TID */
1397  skey->scantid = scantid;
1398 
1399  /*
1400  * * Item order check *
1401  *
1402  * Check that items are stored on page in logical order, by checking
1403  * current item is strictly less than next item (if any).
1404  */
1405  if (OffsetNumberNext(offset) <= max &&
1406  !invariant_l_offset(state, skey, OffsetNumberNext(offset)))
1407  {
1408  ItemPointer tid;
1409  char *itid,
1410  *htid,
1411  *nitid,
1412  *nhtid;
1413 
1414  itid = psprintf("(%u,%u)", state->targetblock, offset);
1415  tid = BTreeTupleGetPointsToTID(itup);
1416  htid = psprintf("(%u,%u)",
1419  nitid = psprintf("(%u,%u)", state->targetblock,
1420  OffsetNumberNext(offset));
1421 
1422  /* Reuse itup to get pointed-to heap location of second item */
1423  itemid = PageGetItemIdCareful(state, state->targetblock,
1424  state->target,
1425  OffsetNumberNext(offset));
1426  itup = (IndexTuple) PageGetItem(state->target, itemid);
1427  tid = BTreeTupleGetPointsToTID(itup);
1428  nhtid = psprintf("(%u,%u)",
1431 
1432  ereport(ERROR,
1433  (errcode(ERRCODE_INDEX_CORRUPTED),
1434  errmsg("item order invariant violated for index \"%s\"",
1435  RelationGetRelationName(state->rel)),
1436  errdetail_internal("Lower index tid=%s (points to %s tid=%s) "
1437  "higher index tid=%s (points to %s tid=%s) "
1438  "page lsn=%X/%X.",
1439  itid,
1440  P_ISLEAF(topaque) ? "heap" : "index",
1441  htid,
1442  nitid,
1443  P_ISLEAF(topaque) ? "heap" : "index",
1444  nhtid,
1445  (uint32) (state->targetlsn >> 32),
1446  (uint32) state->targetlsn)));
1447  }
1448 
1449  /*
1450  * * Last item check *
1451  *
1452  * Check last item against next/right page's first data item's when
1453  * last item on page is reached. This additional check will detect
1454  * transposed pages iff the supposed right sibling page happens to
1455  * belong before target in the key space. (Otherwise, a subsequent
1456  * heap verification will probably detect the problem.)
1457  *
1458  * This check is similar to the item order check that will have
1459  * already been performed for every other "real" item on target page
1460  * when last item is checked. The difference is that the next item
1461  * (the item that is compared to target's last item) needs to come
1462  * from the next/sibling page. There may not be such an item
1463  * available from sibling for various reasons, though (e.g., target is
1464  * the rightmost page on level).
1465  */
1466  else if (offset == max)
1467  {
1468  BTScanInsert rightkey;
1469 
1470  /* Get item in next/right page */
1471  rightkey = bt_right_page_check_scankey(state);
1472 
1473  if (rightkey &&
1474  !invariant_g_offset(state, rightkey, max))
1475  {
1476  /*
1477  * As explained at length in bt_right_page_check_scankey(),
1478  * there is a known !readonly race that could account for
1479  * apparent violation of invariant, which we must check for
1480  * before actually proceeding with raising error. Our canary
1481  * condition is that target page was deleted.
1482  */
1483  if (!state->readonly)
1484  {
1485  /* Get fresh copy of target page */
1486  state->target = palloc_btree_page(state, state->targetblock);
1487  /* Note that we deliberately do not update target LSN */
1488  topaque = (BTPageOpaque) PageGetSpecialPointer(state->target);
1489 
1490  /*
1491  * All !readonly checks now performed; just return
1492  */
1493  if (P_IGNORE(topaque))
1494  return;
1495  }
1496 
1497  ereport(ERROR,
1498  (errcode(ERRCODE_INDEX_CORRUPTED),
1499  errmsg("cross page item order invariant violated for index \"%s\"",
1500  RelationGetRelationName(state->rel)),
1501  errdetail_internal("Last item on page tid=(%u,%u) page lsn=%X/%X.",
1502  state->targetblock, offset,
1503  (uint32) (state->targetlsn >> 32),
1504  (uint32) state->targetlsn)));
1505  }
1506  }
1507 
1508  /*
1509  * * Downlink check *
1510  *
1511  * Additional check of child items iff this is an internal page and
1512  * caller holds a ShareLock. This happens for every downlink (item)
1513  * in target excluding the negative-infinity downlink (again, this is
1514  * because it has no useful value to compare).
1515  */
1516  if (!P_ISLEAF(topaque) && state->readonly)
1517  bt_child_check(state, skey, offset);
1518  }
1519 
1520  /*
1521  * Special case bt_child_highkey_check() call
1522  *
1523  * We don't pass an real downlink, but we've to finish the level
1524  * processing. If condition is satisfied, we've already processed all the
1525  * downlinks from the target level. But there still might be pages to the
1526  * right of the child page pointer to by our rightmost downlink. And they
1527  * might have missing downlinks. This final call checks for them.
1528  */
1529  if (!P_ISLEAF(topaque) && P_RIGHTMOST(topaque) && state->readonly)
1530  {
1532  NULL, topaque->btpo.level);
1533  }
1534 }
int32 ItemPointerCompare(ItemPointer arg1, ItemPointer arg2)
Definition: itemptr.c:52
#define ItemPointerGetOffsetNumberNoCheck(pointer)
Definition: itemptr.h:108
static bool invariant_leq_offset(BtreeCheckState *state, BTScanInsert key, OffsetNumber upperbound)
static ItemPointer BTreeTupleGetPointsToTID(IndexTuple itup)
BlockNumber targetblock
Definition: verify_nbtree.c:93
int errhint(const char *fmt,...)
Definition: elog.c:1068
#define P_IGNORE(opaque)
Definition: nbtree.h:219
static ItemPointer BTreeTupleGetHeapTID(IndexTuple itup)
Definition: nbtree.h:506
ItemPointer scantid
Definition: nbtree.h:664
static Page palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum)
void bloom_add_element(bloom_filter *filter, unsigned char *elem, size_t len)
Definition: bloomfilter.c:136
char * psprintf(const char *fmt,...)
Definition: psprintf.c:46
#define P_FIRSTDATAKEY(opaque)
Definition: nbtree.h:244
static IndexTuple bt_normalize_tuple(BtreeCheckState *state, IndexTuple itup)
union BTPageOpaqueData::@45 btpo
#define BTMaxItemSizeNoHeapTid(page)
Definition: nbtree.h:163
int errcode(int sqlerrcode)
Definition: elog.c:610
static BTScanInsert bt_right_page_check_scankey(BtreeCheckState *state)
#define ItemIdIsDead(itemId)
Definition: itemid.h:113
#define BTreeTupleGetNAtts(itup, rel)
Definition: nbtree.h:445
#define PageGetMaxOffsetNumber(page)
Definition: bufpage.h:357
BTPageOpaqueData * BTPageOpaque
Definition: nbtree.h:69
bloom_filter * filter
int errdetail_internal(const char *fmt,...)
Definition: elog.c:981
uint16 OffsetNumber
Definition: off.h:24
static bool invariant_l_offset(BtreeCheckState *state, BTScanInsert key, OffsetNumber upperbound)
static bool invariant_g_offset(BtreeCheckState *state, BTScanInsert key, OffsetNumber lowerbound)
XLogRecPtr targetlsn
Definition: verify_nbtree.c:95
void pfree(void *pointer)
Definition: mcxt.c:1057
#define ItemIdGetLength(itemId)
Definition: itemid.h:59
#define ERROR
Definition: elog.h:43
#define DEBUG2
Definition: elog.h:24
IndexTupleData * IndexTuple
Definition: itup.h:53
#define RelationGetRelationName(relation)
Definition: rel.h:490
unsigned int uint32
Definition: c.h:375
static ItemPointer BTreeTupleGetMaxHeapTID(IndexTuple itup)
Definition: nbtree.h:532
uint32 level
Definition: nbtree.h:62
static BTScanInsert bt_mkscankey_pivotsearch(Relation rel, IndexTuple itup)
#define InvalidOffsetNumber
Definition: off.h:26
#define ereport(elevel,...)
Definition: elog.h:144
static ItemPointer BTreeTupleGetPostingN(IndexTuple posting, int n)
Definition: nbtree.h:412
static bool BTreeTupleIsPosting(IndexTuple itup)
Definition: nbtree.h:360
int errmsg_internal(const char *fmt,...)
Definition: elog.c:908
bool _bt_check_natts(Relation rel, bool heapkeyspace, Page page, OffsetNumber offnum)
Definition: nbtutils.c:2465
static void bt_child_highkey_check(BtreeCheckState *state, OffsetNumber target_downlinkoffnum, Page loaded_child, uint32 target_level)
bool heapkeyspace
Definition: nbtree.h:659
#define OffsetNumberNext(offsetNumber)
Definition: off.h:52
#define PageGetSpecialPointer(page)
Definition: bufpage.h:326
#define ItemPointerGetOffsetNumber(pointer)
Definition: itemptr.h:117
static void bt_child_check(BtreeCheckState *state, BTScanInsert targetkey, OffsetNumber downlinkoffnum)
#define BTMaxItemSize(page)
Definition: nbtree.h:157
#define P_HIKEY
Definition: nbtree.h:242
static bool bt_rootdescend(BtreeCheckState *state, IndexTuple itup)
int errmsg(const char *fmt,...)
Definition: elog.c:821
static ItemId PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block, Page page, OffsetNumber offset)
#define ItemPointerGetBlockNumberNoCheck(pointer)
Definition: itemptr.h:89
#define elog(elevel,...)
Definition: elog.h:214
int i
static uint16 BTreeTupleGetNPosting(IndexTuple posting)
Definition: nbtree.h:386
static bool offset_is_negative_infinity(BTPageOpaque opaque, OffsetNumber offset)
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:99
#define ItemPointerGetBlockNumber(pointer)
Definition: itemptr.h:98
#define P_RIGHTMOST(opaque)
Definition: nbtree.h:213
#define PageGetItem(page, itemId)
Definition: bufpage.h:340
#define IndexTupleSize(itup)
Definition: itup.h:71
#define ItemPointerCopy(fromPointer, toPointer)
Definition: itemptr.h:161
static IndexTuple bt_posting_plain_tuple(IndexTuple itup, int n)
#define P_ISLEAF(opaque)
Definition: nbtree.h:214

◆ bt_tuple_present_callback()

static void bt_tuple_present_callback ( Relation  index,
ItemPointer  tid,
Datum values,
bool isnull,
bool  tupleIsAlive,
void *  checkstate 
)
static

Definition at line 2471 of file verify_nbtree.c.

References Assert, bloom_lacks_element(), bt_normalize_tuple(), ereport, errcode(), ERRCODE_DATA_CORRUPTED, errhint(), errmsg(), ERROR, BtreeCheckState::filter, BtreeCheckState::heapallindexed, BtreeCheckState::heaprel, BtreeCheckState::heaptuplespresent, index_form_tuple(), IndexTupleSize, ItemPointerGetBlockNumber, ItemPointerGetOffsetNumber, pfree(), BtreeCheckState::readonly, BtreeCheckState::rel, RelationGetDescr, RelationGetRelationName, and IndexTupleData::t_tid.

Referenced by bt_check_every_level().

2473 {
2474  BtreeCheckState *state = (BtreeCheckState *) checkstate;
2475  IndexTuple itup,
2476  norm;
2477 
2478  Assert(state->heapallindexed);
2479 
2480  /* Generate a normalized index tuple for fingerprinting */
2481  itup = index_form_tuple(RelationGetDescr(index), values, isnull);
2482  itup->t_tid = *tid;
2483  norm = bt_normalize_tuple(state, itup);
2484 
2485  /* Probe Bloom filter -- tuple should be present */
2486  if (bloom_lacks_element(state->filter, (unsigned char *) norm,
2487  IndexTupleSize(norm)))
2488  ereport(ERROR,
2490  errmsg("heap tuple (%u,%u) from table \"%s\" lacks matching index tuple within index \"%s\"",
2491  ItemPointerGetBlockNumber(&(itup->t_tid)),
2494  RelationGetRelationName(state->rel)),
2495  !state->readonly
2496  ? errhint("Retrying verification using the function bt_index_parent_check() might provide a more specific error.")
2497  : 0));
2498 
2499  state->heaptuplespresent++;
2500  pfree(itup);
2501  /* Cannot leak memory here */
2502  if (norm != itup)
2503  pfree(norm);
2504 }
int errhint(const char *fmt,...)
Definition: elog.c:1068
#define RelationGetDescr(relation)
Definition: rel.h:482
static IndexTuple bt_normalize_tuple(BtreeCheckState *state, IndexTuple itup)
ItemPointerData t_tid
Definition: itup.h:37
int errcode(int sqlerrcode)
Definition: elog.c:610
bloom_filter * filter
IndexTuple index_form_tuple(TupleDesc tupleDescriptor, Datum *values, bool *isnull)
Definition: indextuple.c:47
void pfree(void *pointer)
Definition: mcxt.c:1057
#define ERROR
Definition: elog.h:43
#define RelationGetRelationName(relation)
Definition: rel.h:490
#define ERRCODE_DATA_CORRUPTED
Definition: pg_basebackup.c:45
Relation heaprel
Definition: verify_nbtree.c:72
#define ereport(elevel,...)
Definition: elog.h:144
#define Assert(condition)
Definition: c.h:746
Definition: regguts.h:298
#define ItemPointerGetOffsetNumber(pointer)
Definition: itemptr.h:117
static Datum values[MAXATTR]
Definition: bootstrap.c:165
int errmsg(const char *fmt,...)
Definition: elog.c:821
#define ItemPointerGetBlockNumber(pointer)
Definition: itemptr.h:98
bool bloom_lacks_element(bloom_filter *filter, unsigned char *elem, size_t len)
Definition: bloomfilter.c:158
#define IndexTupleSize(itup)
Definition: itup.h:71

◆ btree_index_checkable()

static void btree_index_checkable ( Relation  rel)
inlinestatic

Definition at line 348 of file verify_nbtree.c.

References ereport, errcode(), errdetail(), errmsg(), ERROR, RelationData::rd_index, RelationData::rd_rel, RELATION_IS_OTHER_TEMP, and RelationGetRelationName.

Referenced by bt_index_check_internal().

349 {
350  if (rel->rd_rel->relkind != RELKIND_INDEX ||
351  rel->rd_rel->relam != BTREE_AM_OID)
352  ereport(ERROR,
353  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
354  errmsg("only B-Tree indexes are supported as targets for verification"),
355  errdetail("Relation \"%s\" is not a B-Tree index.",
356  RelationGetRelationName(rel))));
357 
358  if (RELATION_IS_OTHER_TEMP(rel))
359  ereport(ERROR,
360  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
361  errmsg("cannot access temporary tables of other sessions"),
362  errdetail("Index \"%s\" is associated with temporary relation.",
363  RelationGetRelationName(rel))));
364 
365  if (!rel->rd_index->indisvalid)
366  ereport(ERROR,
367  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
368  errmsg("cannot check index \"%s\"",
370  errdetail("Index is not valid.")));
371 }
int errcode(int sqlerrcode)
Definition: elog.c:610
Form_pg_class rd_rel
Definition: rel.h:109
Form_pg_index rd_index
Definition: rel.h:174
#define ERROR
Definition: elog.h:43
int errdetail(const char *fmt,...)
Definition: elog.c:954
#define RelationGetRelationName(relation)
Definition: rel.h:490
#define ereport(elevel,...)
Definition: elog.h:144
#define RELATION_IS_OTHER_TEMP(relation)
Definition: rel.h:593
int errmsg(const char *fmt,...)
Definition: elog.c:821

◆ btree_index_mainfork_expected()

static bool btree_index_mainfork_expected ( Relation  rel)
inlinestatic

Definition at line 381 of file verify_nbtree.c.

References ereport, errcode(), errmsg(), NOTICE, RelationData::rd_rel, RecoveryInProgress(), and RelationGetRelationName.

Referenced by bt_index_check_internal().

382 {
383  if (rel->rd_rel->relpersistence != RELPERSISTENCE_UNLOGGED ||
385  return true;
386 
387  ereport(NOTICE,
388  (errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
389  errmsg("cannot verify unlogged index \"%s\" during recovery, skipping",
390  RelationGetRelationName(rel))));
391 
392  return false;
393 }
int errcode(int sqlerrcode)
Definition: elog.c:610
Form_pg_class rd_rel
Definition: rel.h:109
bool RecoveryInProgress(void)
Definition: xlog.c:8076
#define RelationGetRelationName(relation)
Definition: rel.h:490
#define ereport(elevel,...)
Definition: elog.h:144
#define NOTICE
Definition: elog.h:37
int errmsg(const char *fmt,...)
Definition: elog.c:821

◆ BTreeTupleGetHeapTIDCareful()

static ItemPointer BTreeTupleGetHeapTIDCareful ( BtreeCheckState state,
IndexTuple  itup,
bool  nonpivot 
)
inlinestatic

Definition at line 3164 of file verify_nbtree.c.

References Assert, BTreeTupleGetHeapTID(), BTreeTupleIsPivot(), ereport, errcode(), errmsg(), errmsg_internal(), ERROR, BtreeCheckState::heapkeyspace, ItemPointerIsValid, BtreeCheckState::rel, RelationGetRelationName, and BtreeCheckState::targetblock.

Referenced by invariant_l_nontarget_offset(), and invariant_l_offset().

3166 {
3167  ItemPointer htid;
3168 
3169  /*
3170  * Caller determines whether this is supposed to be a pivot or non-pivot
3171  * tuple using page type and item offset number. Verify that tuple
3172  * metadata agrees with this.
3173  */
3174  Assert(state->heapkeyspace);
3175  if (BTreeTupleIsPivot(itup) && nonpivot)
3176  ereport(ERROR,
3177  (errcode(ERRCODE_INDEX_CORRUPTED),
3178  errmsg_internal("block %u or its right sibling block or child block in index \"%s\" has unexpected pivot tuple",
3179  state->targetblock,
3180  RelationGetRelationName(state->rel))));
3181 
3182  if (!BTreeTupleIsPivot(itup) && !nonpivot)
3183  ereport(ERROR,
3184  (errcode(ERRCODE_INDEX_CORRUPTED),
3185  errmsg_internal("block %u or its right sibling block or child block in index \"%s\" has unexpected non-pivot tuple",
3186  state->targetblock,
3187  RelationGetRelationName(state->rel))));
3188 
3189  htid = BTreeTupleGetHeapTID(itup);
3190  if (!ItemPointerIsValid(htid) && nonpivot)
3191  ereport(ERROR,
3192  (errcode(ERRCODE_INDEX_CORRUPTED),
3193  errmsg("block %u or its right sibling block or child block in index \"%s\" contains non-pivot tuple that lacks a heap TID",
3194  state->targetblock,
3195  RelationGetRelationName(state->rel))));
3196 
3197  return htid;
3198 }
#define ItemPointerIsValid(pointer)
Definition: itemptr.h:82
BlockNumber targetblock
Definition: verify_nbtree.c:93
static bool BTreeTupleIsPivot(IndexTuple itup)
Definition: nbtree.h:348
static ItemPointer BTreeTupleGetHeapTID(IndexTuple itup)
Definition: nbtree.h:506
int errcode(int sqlerrcode)
Definition: elog.c:610
#define ERROR
Definition: elog.h:43
#define RelationGetRelationName(relation)
Definition: rel.h:490
#define ereport(elevel,...)
Definition: elog.h:144
int errmsg_internal(const char *fmt,...)
Definition: elog.c:908
#define Assert(condition)
Definition: c.h:746
int errmsg(const char *fmt,...)
Definition: elog.c:821

◆ BTreeTupleGetPointsToTID()

static ItemPointer BTreeTupleGetPointsToTID ( IndexTuple  itup)
inlinestatic

Definition at line 3212 of file verify_nbtree.c.

References BTreeTupleGetHeapTID(), BTreeTupleIsPivot(), and IndexTupleData::t_tid.

Referenced by bt_target_page_check().

3213 {
3214  /*
3215  * Rely on the assumption that !heapkeyspace internal page data items will
3216  * correctly return TID with downlink here -- BTreeTupleGetHeapTID() won't
3217  * recognize it as a pivot tuple, but everything still works out because
3218  * the t_tid field is still returned
3219  */
3220  if (!BTreeTupleIsPivot(itup))
3221  return BTreeTupleGetHeapTID(itup);
3222 
3223  /* Pivot tuple returns TID with downlink block (heapkeyspace variant) */
3224  return &itup->t_tid;
3225 }
static bool BTreeTupleIsPivot(IndexTuple itup)
Definition: nbtree.h:348
static ItemPointer BTreeTupleGetHeapTID(IndexTuple itup)
Definition: nbtree.h:506
ItemPointerData t_tid
Definition: itup.h:37

◆ invariant_g_offset()

static bool invariant_g_offset ( BtreeCheckState state,
BTScanInsert  key,
OffsetNumber  lowerbound 
)
inlinestatic

Definition at line 2847 of file verify_nbtree.c.

References _bt_compare(), Assert, cmp(), BTScanInsertData::heapkeyspace, BTScanInsertData::pivotsearch, BtreeCheckState::rel, and BtreeCheckState::target.

Referenced by bt_target_page_check().

2849 {
2850  int32 cmp;
2851 
2852  Assert(key->pivotsearch);
2853 
2854  cmp = _bt_compare(state->rel, key, state->target, lowerbound);
2855 
2856  /* pg_upgrade'd indexes may legally have equal sibling tuples */
2857  if (!key->heapkeyspace)
2858  return cmp >= 0;
2859 
2860  /*
2861  * No need to consider the possibility that scankey has attributes that we
2862  * need to force to be interpreted as negative infinity. _bt_compare() is
2863  * able to determine that scankey is greater than negative infinity. The
2864  * distinction between "==" and "<" isn't interesting here, since
2865  * corruption is indicated either way.
2866  */
2867  return cmp > 0;
2868 }
signed int int32
Definition: c.h:363
int32 _bt_compare(Relation rel, BTScanInsert key, Page page, OffsetNumber offnum)
Definition: nbtsearch.c:644
bool pivotsearch
Definition: nbtree.h:663
#define Assert(condition)
Definition: c.h:746
bool heapkeyspace
Definition: nbtree.h:659
static int cmp(const chr *x, const chr *y, size_t len)
Definition: regc_locale.c:742

◆ invariant_l_nontarget_offset()

static bool invariant_l_nontarget_offset ( BtreeCheckState state,
BTScanInsert  key,
BlockNumber  nontargetblock,
Page  nontarget,
OffsetNumber  upperbound 
)
inlinestatic

Definition at line 2883 of file verify_nbtree.c.

References _bt_compare(), Assert, BTreeTupleGetHeapTIDCareful(), BTreeTupleGetNKeyAtts, cmp(), BTScanInsertData::heapkeyspace, BTScanInsertData::keysz, P_FIRSTDATAKEY, P_ISLEAF, PageGetItem, PageGetItemIdCareful(), PageGetSpecialPointer, BTScanInsertData::pivotsearch, BtreeCheckState::rel, and BTScanInsertData::scantid.

Referenced by bt_child_check().

2886 {
2887  ItemId itemid;
2888  int32 cmp;
2889 
2890  Assert(key->pivotsearch);
2891 
2892  /* Verify line pointer before checking tuple */
2893  itemid = PageGetItemIdCareful(state, nontargetblock, nontarget,
2894  upperbound);
2895  cmp = _bt_compare(state->rel, key, nontarget, upperbound);
2896 
2897  /* pg_upgrade'd indexes may legally have equal sibling tuples */
2898  if (!key->heapkeyspace)
2899  return cmp <= 0;
2900 
2901  /* See invariant_l_offset() for an explanation of this extra step */
2902  if (cmp == 0)
2903  {
2904  IndexTuple child;
2905  int uppnkeyatts;
2906  ItemPointer childheaptid;
2907  BTPageOpaque copaque;
2908  bool nonpivot;
2909 
2910  child = (IndexTuple) PageGetItem(nontarget, itemid);
2911  copaque = (BTPageOpaque) PageGetSpecialPointer(nontarget);
2912  nonpivot = P_ISLEAF(copaque) && upperbound >= P_FIRSTDATAKEY(copaque);
2913 
2914  /* Get number of keys + heap TID for child/non-target item */
2915  uppnkeyatts = BTreeTupleGetNKeyAtts(child, state->rel);
2916  childheaptid = BTreeTupleGetHeapTIDCareful(state, child, nonpivot);
2917 
2918  /* Heap TID is tiebreaker key attribute */
2919  if (key->keysz == uppnkeyatts)
2920  return key->scantid == NULL && childheaptid != NULL;
2921 
2922  return key->keysz < uppnkeyatts;
2923  }
2924 
2925  return cmp < 0;
2926 }
ItemPointer scantid
Definition: nbtree.h:664
#define P_FIRSTDATAKEY(opaque)
Definition: nbtree.h:244
BTPageOpaqueData * BTPageOpaque
Definition: nbtree.h:69
signed int int32
Definition: c.h:363
IndexTupleData * IndexTuple
Definition: itup.h:53
int32 _bt_compare(Relation rel, BTScanInsert key, Page page, OffsetNumber offnum)
Definition: nbtsearch.c:644
static ItemPointer BTreeTupleGetHeapTIDCareful(BtreeCheckState *state, IndexTuple itup, bool nonpivot)
bool pivotsearch
Definition: nbtree.h:663
#define Assert(condition)
Definition: c.h:746
#define BTreeTupleGetNKeyAtts(itup, rel)
Definition: verify_nbtree.c:50
bool heapkeyspace
Definition: nbtree.h:659
#define PageGetSpecialPointer(page)
Definition: bufpage.h:326
static ItemId PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block, Page page, OffsetNumber offset)
#define PageGetItem(page, itemId)
Definition: bufpage.h:340
static int cmp(const chr *x, const chr *y, size_t len)
Definition: regc_locale.c:742
#define P_ISLEAF(opaque)
Definition: nbtree.h:214

◆ invariant_l_offset()

static bool invariant_l_offset ( BtreeCheckState state,
BTScanInsert  key,
OffsetNumber  upperbound 
)
inlinestatic

Definition at line 2761 of file verify_nbtree.c.

References _bt_compare(), Assert, BTreeTupleGetHeapTIDCareful(), BTreeTupleGetNKeyAtts, cmp(), BTScanInsertData::heapkeyspace, invariant_leq_offset(), BTScanInsertData::keysz, P_FIRSTDATAKEY, P_ISLEAF, PageGetItem, PageGetItemIdCareful(), PageGetSpecialPointer, BTScanInsertData::pivotsearch, BtreeCheckState::rel, BTScanInsertData::scantid, BtreeCheckState::target, and BtreeCheckState::targetblock.

Referenced by bt_target_page_check().

2763 {
2764  ItemId itemid;
2765  int32 cmp;
2766 
2767  Assert(key->pivotsearch);
2768 
2769  /* Verify line pointer before checking tuple */
2770  itemid = PageGetItemIdCareful(state, state->targetblock, state->target,
2771  upperbound);
2772  /* pg_upgrade'd indexes may legally have equal sibling tuples */
2773  if (!key->heapkeyspace)
2774  return invariant_leq_offset(state, key, upperbound);
2775 
2776  cmp = _bt_compare(state->rel, key, state->target, upperbound);
2777 
2778  /*
2779  * _bt_compare() is capable of determining that a scankey with a
2780  * filled-out attribute is greater than pivot tuples where the comparison
2781  * is resolved at a truncated attribute (value of attribute in pivot is
2782  * minus infinity). However, it is not capable of determining that a
2783  * scankey is _less than_ a tuple on the basis of a comparison resolved at
2784  * _scankey_ minus infinity attribute. Complete an extra step to simulate
2785  * having minus infinity values for omitted scankey attribute(s).
2786  */
2787  if (cmp == 0)
2788  {
2789  BTPageOpaque topaque;
2790  IndexTuple ritup;
2791  int uppnkeyatts;
2792  ItemPointer rheaptid;
2793  bool nonpivot;
2794 
2795  ritup = (IndexTuple) PageGetItem(state->target, itemid);
2796  topaque = (BTPageOpaque) PageGetSpecialPointer(state->target);
2797  nonpivot = P_ISLEAF(topaque) && upperbound >= P_FIRSTDATAKEY(topaque);
2798 
2799  /* Get number of keys + heap TID for item to the right */
2800  uppnkeyatts = BTreeTupleGetNKeyAtts(ritup, state->rel);
2801  rheaptid = BTreeTupleGetHeapTIDCareful(state, ritup, nonpivot);
2802 
2803  /* Heap TID is tiebreaker key attribute */
2804  if (key->keysz == uppnkeyatts)
2805  return key->scantid == NULL && rheaptid != NULL;
2806 
2807  return key->keysz < uppnkeyatts;
2808  }
2809 
2810  return cmp < 0;
2811 }
static bool invariant_leq_offset(BtreeCheckState *state, BTScanInsert key, OffsetNumber upperbound)
BlockNumber targetblock
Definition: verify_nbtree.c:93
ItemPointer scantid
Definition: nbtree.h:664
#define P_FIRSTDATAKEY(opaque)
Definition: nbtree.h:244
BTPageOpaqueData * BTPageOpaque
Definition: nbtree.h:69
signed int int32
Definition: c.h:363
IndexTupleData * IndexTuple
Definition: itup.h:53
int32 _bt_compare(Relation rel, BTScanInsert key, Page page, OffsetNumber offnum)
Definition: nbtsearch.c:644
static ItemPointer BTreeTupleGetHeapTIDCareful(BtreeCheckState *state, IndexTuple itup, bool nonpivot)
bool pivotsearch
Definition: nbtree.h:663
#define Assert(condition)
Definition: c.h:746
#define BTreeTupleGetNKeyAtts(itup, rel)
Definition: verify_nbtree.c:50
bool heapkeyspace
Definition: nbtree.h:659
#define PageGetSpecialPointer(page)
Definition: bufpage.h:326
static ItemId PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block, Page page, OffsetNumber offset)
#define PageGetItem(page, itemId)
Definition: bufpage.h:340
static int cmp(const chr *x, const chr *y, size_t len)
Definition: regc_locale.c:742
#define P_ISLEAF(opaque)
Definition: nbtree.h:214

◆ invariant_leq_offset()

static bool invariant_leq_offset ( BtreeCheckState state,
BTScanInsert  key,
OffsetNumber  upperbound 
)
inlinestatic

Definition at line 2824 of file verify_nbtree.c.

References _bt_compare(), Assert, cmp(), BTScanInsertData::pivotsearch, BtreeCheckState::rel, and BtreeCheckState::target.

Referenced by bt_target_page_check(), and invariant_l_offset().

2826 {
2827  int32 cmp;
2828 
2829  Assert(key->pivotsearch);
2830 
2831  cmp = _bt_compare(state->rel, key, state->target, upperbound);
2832 
2833  return cmp <= 0;
2834 }
signed int int32
Definition: c.h:363
int32 _bt_compare(Relation rel, BTScanInsert key, Page page, OffsetNumber offnum)
Definition: nbtsearch.c:644
bool pivotsearch
Definition: nbtree.h:663
#define Assert(condition)
Definition: c.h:746
static int cmp(const chr *x, const chr *y, size_t len)
Definition: regc_locale.c:742

◆ offset_is_negative_infinity()

static bool offset_is_negative_infinity ( BTPageOpaque  opaque,
OffsetNumber  offset 
)
inlinestatic

Definition at line 2726 of file verify_nbtree.c.

References P_FIRSTDATAKEY, and P_ISLEAF.

Referenced by bt_child_check(), bt_child_highkey_check(), and bt_target_page_check().

2727 {
2728  /*
2729  * For internal pages only, the first item after high key, if any, is
2730  * negative infinity item. Internal pages always have a negative infinity
2731  * item, whereas leaf pages never have one. This implies that negative
2732  * infinity item is either first or second line item, or there is none
2733  * within page.
2734  *
2735  * Negative infinity items are a special case among pivot tuples. They
2736  * always have zero attributes, while all other pivot tuples always have
2737  * nkeyatts attributes.
2738  *
2739  * Right-most pages don't have a high key, but could be said to
2740  * conceptually have a "positive infinity" high key. Thus, there is a
2741  * symmetry between down link items in parent pages, and high keys in
2742  * children. Together, they represent the part of the key space that
2743  * belongs to each page in the index. For example, all children of the
2744  * root page will have negative infinity as a lower bound from root
2745  * negative infinity downlink, and positive infinity as an upper bound
2746  * (implicitly, from "imaginary" positive infinity high key in root).
2747  */
2748  return !P_ISLEAF(opaque) && offset == P_FIRSTDATAKEY(opaque);
2749 }
#define P_FIRSTDATAKEY(opaque)
Definition: nbtree.h:244
#define P_ISLEAF(opaque)
Definition: nbtree.h:214

◆ PageGetItemIdCareful()

static ItemId PageGetItemIdCareful ( BtreeCheckState state,
BlockNumber  block,
Page  page,
OffsetNumber  offset 
)
static

Definition at line 3124 of file verify_nbtree.c.

References ereport, errcode(), errdetail_internal(), errmsg(), ERROR, ItemIdGetFlags, ItemIdGetLength, ItemIdGetOffset, ItemIdIsRedirected, ItemIdIsUsed, PageGetItemId, BtreeCheckState::rel, and RelationGetRelationName.

Referenced by bt_check_level_from_leftmost(), bt_child_check(), bt_child_highkey_check(), bt_downlink_missing_check(), bt_right_page_check_scankey(), bt_target_page_check(), invariant_l_nontarget_offset(), and invariant_l_offset().

3126 {
3127  ItemId itemid = PageGetItemId(page, offset);
3128 
3129  if (ItemIdGetOffset(itemid) + ItemIdGetLength(itemid) >
3130  BLCKSZ - sizeof(BTPageOpaqueData))
3131  ereport(ERROR,
3132  (errcode(ERRCODE_INDEX_CORRUPTED),
3133  errmsg("line pointer points past end of tuple space in index \"%s\"",
3134  RelationGetRelationName(state->rel)),
3135  errdetail_internal("Index tid=(%u,%u) lp_off=%u, lp_len=%u lp_flags=%u.",
3136  block, offset, ItemIdGetOffset(itemid),
3137  ItemIdGetLength(itemid),
3138  ItemIdGetFlags(itemid))));
3139 
3140  /*
3141  * Verify that line pointer isn't LP_REDIRECT or LP_UNUSED, since nbtree
3142  * never uses either. Verify that line pointer has storage, too, since
3143  * even LP_DEAD items should within nbtree.
3144  */
3145  if (ItemIdIsRedirected(itemid) || !ItemIdIsUsed(itemid) ||
3146  ItemIdGetLength(itemid) == 0)
3147  ereport(ERROR,
3148  (errcode(ERRCODE_INDEX_CORRUPTED),
3149  errmsg("invalid line pointer storage in index \"%s\"",
3150  RelationGetRelationName(state->rel)),
3151  errdetail_internal("Index tid=(%u,%u) lp_off=%u, lp_len=%u lp_flags=%u.",
3152  block, offset, ItemIdGetOffset(itemid),
3153  ItemIdGetLength(itemid),
3154  ItemIdGetFlags(itemid))));
3155 
3156  return itemid;
3157 }
#define ItemIdIsRedirected(itemId)
Definition: itemid.h:106
#define ItemIdIsUsed(itemId)
Definition: itemid.h:92
int errcode(int sqlerrcode)
Definition: elog.c:610
int errdetail_internal(const char *fmt,...)
Definition: elog.c:981
#define ItemIdGetLength(itemId)
Definition: itemid.h:59
#define ERROR
Definition: elog.h:43
#define RelationGetRelationName(relation)
Definition: rel.h:490
#define ItemIdGetOffset(itemId)
Definition: itemid.h:65
#define PageGetItemId(page, offsetNumber)
Definition: bufpage.h:235
#define ItemIdGetFlags(itemId)
Definition: itemid.h:71
#define ereport(elevel,...)
Definition: elog.h:144
int errmsg(const char *fmt,...)
Definition: elog.c:821

◆ palloc_btree_page()

static Page palloc_btree_page ( BtreeCheckState state,
BlockNumber  blocknum 
)
static

Definition at line 2943 of file verify_nbtree.c.

References _bt_checkpage(), BT_READ, BTMetaPageData::btm_magic, BTMetaPageData::btm_version, BTPageGetMeta, BTPageOpaqueData::btpo, BTREE_MAGIC, BTREE_METAPAGE, BTREE_MIN_VERSION, BTREE_VERSION, BufferGetPage, BtreeCheckState::checkstrategy, ereport, errcode(), errhint(), errmsg(), ERROR, BTPageOpaqueData::level, LockBuffer(), MAIN_FORKNUM, MaxIndexTuplesPerPage, P_FIRSTDATAKEY, P_HAS_GARBAGE, P_HIKEY, P_ISDELETED, P_ISHALFDEAD, P_ISLEAF, P_ISMETA, P_RIGHTMOST, PageGetMaxOffsetNumber, PageGetSpecialPointer, palloc(), RBM_NORMAL, ReadBufferExtended(), BtreeCheckState::rel, RelationGetRelationName, and UnlockReleaseBuffer().

Referenced by bt_check_every_level(), bt_check_level_from_leftmost(), bt_child_check(), bt_child_highkey_check(), bt_downlink_missing_check(), bt_right_page_check_scankey(), and bt_target_page_check().

2944 {
2945  Buffer buffer;
2946  Page page;
2947  BTPageOpaque opaque;
2948  OffsetNumber maxoffset;
2949 
2950  page = palloc(BLCKSZ);
2951 
2952  /*
2953  * We copy the page into local storage to avoid holding pin on the buffer
2954  * longer than we must.
2955  */
2956  buffer = ReadBufferExtended(state->rel, MAIN_FORKNUM, blocknum, RBM_NORMAL,
2957  state->checkstrategy);
2958  LockBuffer(buffer, BT_READ);
2959 
2960  /*
2961  * Perform the same basic sanity checking that nbtree itself performs for
2962  * every page:
2963  */
2964  _bt_checkpage(state->rel, buffer);
2965 
2966  /* Only use copy of page in palloc()'d memory */
2967  memcpy(page, BufferGetPage(buffer), BLCKSZ);
2968  UnlockReleaseBuffer(buffer);
2969 
2970  opaque = (BTPageOpaque) PageGetSpecialPointer(page);
2971 
2972  if (P_ISMETA(opaque) && blocknum != BTREE_METAPAGE)
2973  ereport(ERROR,
2974  (errcode(ERRCODE_INDEX_CORRUPTED),
2975  errmsg("invalid meta page found at block %u in index \"%s\"",
2976  blocknum, RelationGetRelationName(state->rel))));
2977 
2978  /* Check page from block that ought to be meta page */
2979  if (blocknum == BTREE_METAPAGE)
2980  {
2981  BTMetaPageData *metad = BTPageGetMeta(page);
2982 
2983  if (!P_ISMETA(opaque) ||
2984  metad->btm_magic != BTREE_MAGIC)
2985  ereport(ERROR,
2986  (errcode(ERRCODE_INDEX_CORRUPTED),
2987  errmsg("index \"%s\" meta page is corrupt",
2988  RelationGetRelationName(state->rel))));
2989 
2990  if (metad->btm_version < BTREE_MIN_VERSION ||
2991  metad->btm_version > BTREE_VERSION)
2992  ereport(ERROR,
2993  (errcode(ERRCODE_INDEX_CORRUPTED),
2994  errmsg("version mismatch in index \"%s\": file version %d, "
2995  "current version %d, minimum supported version %d",
2996  RelationGetRelationName(state->rel),
2997  metad->btm_version, BTREE_VERSION,
2998  BTREE_MIN_VERSION)));
2999 
3000  /* Finished with metapage checks */
3001  return page;
3002  }
3003 
3004  /*
3005  * Deleted pages have no sane "level" field, so can only check non-deleted
3006  * page level
3007  */
3008  if (P_ISLEAF(opaque) && !P_ISDELETED(opaque) && opaque->btpo.level != 0)
3009  ereport(ERROR,
3010  (errcode(ERRCODE_INDEX_CORRUPTED),
3011  errmsg("invalid leaf page level %u for block %u in index \"%s\"",
3012  opaque->btpo.level, blocknum, RelationGetRelationName(state->rel))));
3013 
3014  if (!P_ISLEAF(opaque) && !P_ISDELETED(opaque) &&
3015  opaque->btpo.level == 0)
3016  ereport(ERROR,
3017  (errcode(ERRCODE_INDEX_CORRUPTED),
3018  errmsg("invalid internal page level 0 for block %u in index \"%s\"",
3019  blocknum, RelationGetRelationName(state->rel))));
3020 
3021  /*
3022  * Sanity checks for number of items on page.
3023  *
3024  * As noted at the beginning of _bt_binsrch(), an internal page must have
3025  * children, since there must always be a negative infinity downlink
3026  * (there may also be a highkey). In the case of non-rightmost leaf
3027  * pages, there must be at least a highkey. The exceptions are deleted
3028  * pages, which contain no items.
3029  *
3030  * This is correct when pages are half-dead, since internal pages are
3031  * never half-dead, and leaf pages must have a high key when half-dead
3032  * (the rightmost page can never be deleted). It's also correct with
3033  * fully deleted pages: _bt_unlink_halfdead_page() doesn't change anything
3034  * about the target page other than setting the page as fully dead, and
3035  * setting its xact field. In particular, it doesn't change the sibling
3036  * links in the deletion target itself, since they're required when index
3037  * scans land on the deletion target, and then need to move right (or need
3038  * to move left, in the case of backward index scans).
3039  */
3040  maxoffset = PageGetMaxOffsetNumber(page);
3041  if (maxoffset > MaxIndexTuplesPerPage)
3042  ereport(ERROR,
3043  (errcode(ERRCODE_INDEX_CORRUPTED),
3044  errmsg("Number of items on block %u of index \"%s\" exceeds MaxIndexTuplesPerPage (%u)",
3045  blocknum, RelationGetRelationName(state->rel),
3047 
3048  if (!P_ISLEAF(opaque) && !P_ISDELETED(opaque) && maxoffset < P_FIRSTDATAKEY(opaque))
3049  ereport(ERROR,
3050  (errcode(ERRCODE_INDEX_CORRUPTED),
3051  errmsg("internal block %u in index \"%s\" lacks high key and/or at least one downlink",
3052  blocknum, RelationGetRelationName(state->rel))));
3053 
3054  if (P_ISLEAF(opaque) && !P_ISDELETED(opaque) && !P_RIGHTMOST(opaque) && maxoffset < P_HIKEY)
3055  ereport(ERROR,
3056  (errcode(ERRCODE_INDEX_CORRUPTED),
3057  errmsg("non-rightmost leaf block %u in index \"%s\" lacks high key item",
3058  blocknum, RelationGetRelationName(state->rel))));
3059 
3060  /*
3061  * In general, internal pages are never marked half-dead, except on
3062  * versions of Postgres prior to 9.4, where it can be valid transient
3063  * state. This state is nonetheless treated as corruption by VACUUM on
3064  * from version 9.4 on, so do the same here. See _bt_pagedel() for full
3065  * details.
3066  *
3067  * Internal pages should never have garbage items, either.
3068  */
3069  if (!P_ISLEAF(opaque) && P_ISHALFDEAD(opaque))
3070  ereport(ERROR,
3071  (errcode(ERRCODE_INDEX_CORRUPTED),
3072  errmsg("internal page block %u in index \"%s\" is half-dead",
3073  blocknum, RelationGetRelationName(state->rel)),
3074  errhint("This can be caused by an interrupted VACUUM in version 9.3 or older, before upgrade. Please REINDEX it.")));
3075 
3076  if (!P_ISLEAF(opaque) && P_HAS_GARBAGE(opaque))
3077  ereport(ERROR,
3078  (errcode(ERRCODE_INDEX_CORRUPTED),
3079  errmsg("internal page block %u in index \"%s\" has garbage items",
3080  blocknum, RelationGetRelationName(state->rel))));
3081 
3082  return page;
3083 }
int errhint(const char *fmt,...)
Definition: elog.c:1068
uint32 btm_version
Definition: nbtree.h:101
#define BTREE_VERSION
Definition: nbtree.h:143
#define P_FIRSTDATAKEY(opaque)
Definition: nbtree.h:244
uint32 btm_magic
Definition: nbtree.h:100
Buffer ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum, ReadBufferMode mode, BufferAccessStrategy strategy)
Definition: bufmgr.c:654
union BTPageOpaqueData::@45 btpo
#define P_HAS_GARBAGE(opaque)
Definition: nbtree.h:220
int errcode(int sqlerrcode)
Definition: elog.c:610
BufferAccessStrategy checkstrategy
Definition: verify_nbtree.c:84
#define PageGetMaxOffsetNumber(page)
Definition: bufpage.h:357
BTPageOpaqueData * BTPageOpaque
Definition: nbtree.h:69
uint16 OffsetNumber
Definition: off.h:24
#define P_ISMETA(opaque)
Definition: nbtree.h:217
#define BT_READ
Definition: nbtree.h:587
#define BTREE_MAGIC
Definition: nbtree.h:142
void _bt_checkpage(Relation rel, Buffer buf)
Definition: nbtpage.c:726
#define P_ISHALFDEAD(opaque)
Definition: nbtree.h:218
void UnlockReleaseBuffer(Buffer buffer)
Definition: bufmgr.c:3536
#define ERROR
Definition: elog.h:43
#define BTPageGetMeta(p)
Definition: nbtree.h:114
#define RelationGetRelationName(relation)
Definition: rel.h:490
#define BufferGetPage(buffer)
Definition: bufmgr.h:169
#define BTREE_METAPAGE
Definition: nbtree.h:141
#define P_ISDELETED(opaque)
Definition: nbtree.h:216
uint32 level
Definition: nbtree.h:62
void LockBuffer(Buffer buffer, int mode)
Definition: bufmgr.c:3752
#define BTREE_MIN_VERSION
Definition: nbtree.h:144
#define ereport(elevel,...)
Definition: elog.h:144
#define PageGetSpecialPointer(page)
Definition: bufpage.h:326
#define P_HIKEY
Definition: nbtree.h:242
#define MaxIndexTuplesPerPage
Definition: itup.h:145
void * palloc(Size size)
Definition: mcxt.c:950
int errmsg(const char *fmt,...)
Definition: elog.c:821
int Buffer
Definition: buf.h:23
#define P_RIGHTMOST(opaque)
Definition: nbtree.h:213
Pointer Page
Definition: bufpage.h:78
#define P_ISLEAF(opaque)
Definition: nbtree.h:214

◆ PG_FUNCTION_INFO_V1() [1/2]

PG_FUNCTION_INFO_V1 ( bt_index_check  )

◆ PG_FUNCTION_INFO_V1() [2/2]

PG_FUNCTION_INFO_V1 ( bt_index_parent_check  )

Variable Documentation

◆ PG_MODULE_MAGIC

PG_MODULE_MAGIC

Definition at line 43 of file verify_nbtree.c.