#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:

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_target_page_check (BtreeCheckState *state)

static BTScanInsert	bt_right_page_check_scankey (BtreeCheckState *state)

static void	bt_downlink_check (BtreeCheckState *state, BTScanInsert targetkey, BlockNumber childblock)

static void	bt_downlink_missing_check (BtreeCheckState *state)

static void	bt_tuple_present_callback (Relation index, HeapTuple htup, Datum values, bool isnull, bool tupleIsAlive, void *checkstate)

static IndexTuple	bt_normalize_tuple (BtreeCheckState *state, IndexTuple itup)

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)

Datum	bt_index_check (PG_FUNCTION_ARGS)

Datum	bt_index_parent_check (PG_FUNCTION_ARGS)

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

typedef struct BtreeCheckState 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 386 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, BtreeCheckState::downlinkfilter, 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, MaxIndexTuplesPerPage, MemoryContextDelete(), P_NONE, palloc0(), palloc_btree_page(), random(), RelationData::rd_index, RelationData::rd_indextuple, RelationData::rd_rel, BtreeCheckState::readonly, RecentGlobalXmin, RegisterSnapshot(), BtreeCheckState::rel, RelationGetNumberOfBlocks, RelationGetRelationName, BtreeCheckState::rightsplit, BtreeCheckState::rootdescend, SnapshotAny, HeapTupleData::t_data, table_beginscan_strat(), table_index_build_scan(), BtreeCheckState::targetcontext, TransactionIdIsValid, TransactionIdPrecedes(), UnregisterSnapshot(), work_mem, and SnapshotData::xmin.

Referenced by bt_index_check_internal().

 {
     BtreeCheckState *state;
     Page        metapage;
     BTMetaPageData *metad;
     uint32      previouslevel;
     BtreeLevel  current;
     Snapshot    snapshot = SnapshotAny;
 
     /*
      * RecentGlobalXmin assertion matches index_getnext_tid().  See note on
      * RecentGlobalXmin/B-Tree page deletion.
      */
     Assert(TransactionIdIsValid(RecentGlobalXmin));
 
     /*
      * Initialize state for entire verification operation
      */
     state = palloc0(sizeof(BtreeCheckState));
     state->rel = rel;
     state->heaprel = heaprel;
     state->heapkeyspace = heapkeyspace;
     state->readonly = readonly;
     state->heapallindexed = heapallindexed;
     state->rootdescend = rootdescend;
 
     if (state->heapallindexed)
     {
         int64       total_pages;
         int64       total_elems;
         uint64      seed;
 
         /*
          * Size Bloom filter based on estimated number of tuples in index,
          * while conservatively assuming that each block must contain at least
          * MaxIndexTuplesPerPage / 5 non-pivot tuples.  (Non-leaf pages cannot
          * contain non-pivot tuples.  That's okay because they generally make
          * up no more than about 1% of all pages in the index.)
          */
         total_pages = RelationGetNumberOfBlocks(rel);
         total_elems = Max(total_pages * (MaxIndexTuplesPerPage / 5),
                           (int64) state->rel->rd_rel->reltuples);
         /* Random seed relies on backend srandom() call to avoid repetition */
         seed = random();
         /* Create Bloom filter to fingerprint index */
         state->filter = bloom_create(total_elems, maintenance_work_mem, seed);
         state->heaptuplespresent = 0;
 
         /*
          * Register our own snapshot in !readonly case, rather than asking
          * table_index_build_scan() to do this for us later.  This needs to
          * happen before index fingerprinting begins, so we can later be
          * certain that index fingerprinting should have reached all tuples
          * returned by table_index_build_scan().
          *
          * In readonly case, we also check for problems with missing
          * downlinks. A second Bloom filter is used for this.
          */
         if (!state->readonly)
         {
             snapshot = RegisterSnapshot(GetTransactionSnapshot());
 
             /*
              * GetTransactionSnapshot() always acquires a new MVCC snapshot in
              * READ COMMITTED mode.  A new snapshot is guaranteed to have all
              * the entries it requires in the index.
              *
              * We must defend against the possibility that an old xact
              * snapshot was returned at higher isolation levels when that
              * snapshot is not safe for index scans of the target index.  This
              * is possible when the snapshot sees tuples that are before the
              * index's indcheckxmin horizon.  Throwing an error here should be
              * very rare.  It doesn't seem worth using a secondary snapshot to
              * avoid this.
              */
             if (IsolationUsesXactSnapshot() && rel->rd_index->indcheckxmin &&
                 !TransactionIdPrecedes(HeapTupleHeaderGetXmin(rel->rd_indextuple->t_data),
                                        snapshot->xmin))
                 ereport(ERROR,
                         (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
                          errmsg("index \"%s\" cannot be verified using transaction snapshot",
                                 RelationGetRelationName(rel))));
         }
         else
         {
             /*
              * Extra readonly downlink check.
              *
              * In readonly case, we know that there cannot be a concurrent
              * page split or a concurrent page deletion, which gives us the
              * opportunity to verify that every non-ignorable page had a
              * downlink one level up.  We must be tolerant of interrupted page
              * splits and page deletions, though.  This is taken care of in
              * bt_downlink_missing_check().
              */
             state->downlinkfilter = bloom_create(total_pages, work_mem, seed);
         }
     }
 
     Assert(!state->rootdescend || state->readonly);
     if (state->rootdescend && !state->heapkeyspace)
         ereport(ERROR,
                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                  errmsg("cannot verify that tuples from index \"%s\" can each be found by an independent index search",
                         RelationGetRelationName(rel)),
                  errhint("Only B-Tree version 4 indexes support rootdescend verification.")));
 
     /* Create context for page */
     state->targetcontext = AllocSetContextCreate(CurrentMemoryContext,
                                                  "amcheck context",
                                                  ALLOCSET_DEFAULT_SIZES);
     state->checkstrategy = GetAccessStrategy(BAS_BULKREAD);
 
     /* Get true root block from meta-page */
     metapage = palloc_btree_page(state, BTREE_METAPAGE);
     metad = BTPageGetMeta(metapage);
 
     /*
      * Certain deletion patterns can result in "skinny" B-Tree indexes, where
      * the fast root and true root differ.
      *
      * Start from the true root, not the fast root, unlike conventional index
      * scans.  This approach is more thorough, and removes the risk of
      * following a stale fast root from the meta page.
      */
     if (metad->btm_fastroot != metad->btm_root)
         ereport(DEBUG1,
                 (errcode(ERRCODE_NO_DATA),
                  errmsg("harmless fast root mismatch in index %s",
                         RelationGetRelationName(rel)),
                  errdetail_internal("Fast root block %u (level %u) differs from true root block %u (level %u).",
                                     metad->btm_fastroot, metad->btm_fastlevel,
                                     metad->btm_root, metad->btm_level)));
 
     /*
      * Starting at the root, verify every level.  Move left to right, top to
      * bottom.  Note that there may be no pages other than the meta page (meta
      * page can indicate that root is P_NONE when the index is totally empty).
      */
     previouslevel = InvalidBtreeLevel;
     current.level = metad->btm_level;
     current.leftmost = metad->btm_root;
     current.istruerootlevel = true;
     while (current.leftmost != P_NONE)
     {
         /*
          * Leftmost page on level cannot be right half of incomplete split.
          * This can go stale immediately in !readonly case.
          */
         state->rightsplit = false;
 
         /*
          * Verify this level, and get left most page for next level down, if
          * not at leaf level
          */
         current = bt_check_level_from_leftmost(state, current);
 
         if (current.leftmost == InvalidBlockNumber)
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("index \"%s\" has no valid pages on level below %u or first level",
                             RelationGetRelationName(rel), previouslevel)));
 
         previouslevel = current.level;
     }
 
     /*
      * * Check whether heap contains unindexed/malformed tuples *
      */
     if (state->heapallindexed)
     {
         IndexInfo  *indexinfo = BuildIndexInfo(state->rel);
         TableScanDesc scan;
 
         /* Report on extra downlink checks performed in readonly case */
         if (state->readonly)
         {
             ereport(DEBUG1,
                     (errmsg_internal("finished verifying presence of downlink blocks within index \"%s\" with bitset %.2f%% set",
                                      RelationGetRelationName(rel),
                                      100.0 * bloom_prop_bits_set(state->downlinkfilter))));
             bloom_free(state->downlinkfilter);
         }
 
         /*
          * Create our own scan for table_index_build_scan(), rather than
          * getting it to do so for us.  This is required so that we can
          * actually use the MVCC snapshot registered earlier in !readonly
          * case.
          *
          * Note that table_index_build_scan() calls heap_endscan() for us.
          */
         scan = table_beginscan_strat(state->heaprel,    /* relation */
                                      snapshot,  /* snapshot */
                                      0, /* number of keys */
                                      NULL,  /* scan key */
                                      true,  /* buffer access strategy OK */
                                      true); /* syncscan OK? */
 
         /*
          * Scan will behave as the first scan of a CREATE INDEX CONCURRENTLY
          * behaves in !readonly case.
          *
          * It's okay that we don't actually use the same lock strength for the
          * heap relation as any other ii_Concurrent caller would in !readonly
          * case.  We have no reason to care about a concurrent VACUUM
          * operation, since there isn't going to be a second scan of the heap
          * that needs to be sure that there was no concurrent recycling of
          * TIDs.
          */
         indexinfo->ii_Concurrent = !state->readonly;
 
         /*
          * Don't wait for uncommitted tuple xact commit/abort when index is a
          * unique index on a catalog (or an index used by an exclusion
          * constraint).  This could otherwise happen in the readonly case.
          */
         indexinfo->ii_Unique = false;
         indexinfo->ii_ExclusionOps = NULL;
         indexinfo->ii_ExclusionProcs = NULL;
         indexinfo->ii_ExclusionStrats = NULL;
 
         elog(DEBUG1, "verifying that tuples from index \"%s\" are present in \"%s\"",
              RelationGetRelationName(state->rel),
              RelationGetRelationName(state->heaprel));
 
         table_index_build_scan(state->heaprel, state->rel, indexinfo, true, false,
                                bt_tuple_present_callback, (void *) state, scan);
 
         ereport(DEBUG1,
                 (errmsg_internal("finished verifying presence of " INT64_FORMAT " tuples from table \"%s\" with bitset %.2f%% set",
                                  state->heaptuplespresent, RelationGetRelationName(heaprel),
                                  100.0 * bloom_prop_bits_set(state->filter))));
 
         if (snapshot != SnapshotAny)
             UnregisterSnapshot(snapshot);
 
         bloom_free(state->filter);
     }
 
     /* Be tidy: */
     MemoryContextDelete(state->targetcontext);
 }

◆ bt_check_level_from_leftmost()

static BtreeLevel bt_check_level_from_leftmost	(	BtreeCheckState *	state,
		BtreeLevel	level
	)

static

Definition at line 650 of file verify_nbtree.c.

References bt_target_page_check(), BTPageOpaqueData::btpo, BTPageOpaqueData::btpo_next, BTPageOpaqueData::btpo_prev, BTreeInnerTupleGetDownLink, CHECK_FOR_INTERRUPTS, DEBUG1, DEBUG2, elog, ereport, errcode(), errdetail_internal(), errmsg(), ERROR, InvalidBlockNumber, InvalidBtreeLevel, BtreeLevel::istruerootlevel, BtreeLevel::leftmost, BTPageOpaqueData::level, BtreeLevel::level, MemoryContextReset(), MemoryContextSwitchTo(), P_FIRSTDATAKEY, P_IGNORE, P_INCOMPLETE_SPLIT, P_ISDELETED, P_ISLEAF, P_ISROOT, P_LEFTMOST, P_NONE, P_RIGHTMOST, PageGetItem, PageGetItemIdCareful(), PageGetLSN, PageGetSpecialPointer, palloc_btree_page(), BtreeCheckState::readonly, BtreeCheckState::rel, RelationGetRelationName, BtreeCheckState::rightsplit, BtreeCheckState::target, BtreeCheckState::targetblock, BtreeCheckState::targetcontext, and BtreeCheckState::targetlsn.

Referenced by bt_check_every_level().

 {
     /* State to establish early, concerning entire level */
     BTPageOpaque opaque;
     MemoryContext oldcontext;
     BtreeLevel  nextleveldown;
 
     /* Variables for iterating across level using right links */
     BlockNumber leftcurrent = P_NONE;
     BlockNumber current = level.leftmost;
 
     /* Initialize return state */
     nextleveldown.leftmost = InvalidBlockNumber;
     nextleveldown.level = InvalidBtreeLevel;
     nextleveldown.istruerootlevel = false;
 
     /* Use page-level context for duration of this call */
     oldcontext = MemoryContextSwitchTo(state->targetcontext);
 
     elog(DEBUG2, "verifying level %u%s", level.level,
          level.istruerootlevel ?
          " (true root level)" : level.level == 0 ? " (leaf level)" : "");
 
     do
     {
         /* Don't rely on CHECK_FOR_INTERRUPTS() calls at lower level */
         CHECK_FOR_INTERRUPTS();
 
         /* Initialize state for this iteration */
         state->targetblock = current;
         state->target = palloc_btree_page(state, state->targetblock);
         state->targetlsn = PageGetLSN(state->target);
 
         opaque = (BTPageOpaque) PageGetSpecialPointer(state->target);
 
         if (P_IGNORE(opaque))
         {
             /*
              * Since there cannot be a concurrent VACUUM operation in readonly
              * mode, and since a page has no links within other pages
              * (siblings and parent) once it is marked fully deleted, it
              * should be impossible to land on a fully deleted page in
              * readonly mode. See bt_downlink_check() for further details.
              *
              * The bt_downlink_check() P_ISDELETED() check is repeated here so
              * that pages that are only reachable through sibling links get
              * checked.
              */
             if (state->readonly && P_ISDELETED(opaque))
                 ereport(ERROR,
                         (errcode(ERRCODE_INDEX_CORRUPTED),
                          errmsg("downlink or sibling link points to deleted block in index \"%s\"",
                                 RelationGetRelationName(state->rel)),
                          errdetail_internal("Block=%u left block=%u left link from block=%u.",
                                             current, leftcurrent, opaque->btpo_prev)));
 
             if (P_RIGHTMOST(opaque))
                 ereport(ERROR,
                         (errcode(ERRCODE_INDEX_CORRUPTED),
                          errmsg("block %u fell off the end of index \"%s\"",
                                 current, RelationGetRelationName(state->rel))));
             else
                 ereport(DEBUG1,
                         (errcode(ERRCODE_NO_DATA),
                          errmsg("block %u of index \"%s\" ignored",
                                 current, RelationGetRelationName(state->rel))));
             goto nextpage;
         }
         else if (nextleveldown.leftmost == InvalidBlockNumber)
         {
             /*
              * A concurrent page split could make the caller supplied leftmost
              * block no longer contain the leftmost page, or no longer be the
              * true root, but where that isn't possible due to heavyweight
              * locking, check that the first valid page meets caller's
              * expectations.
              */
             if (state->readonly)
             {
                 if (!P_LEFTMOST(opaque))
                     ereport(ERROR,
                             (errcode(ERRCODE_INDEX_CORRUPTED),
                              errmsg("block %u is not leftmost in index \"%s\"",
                                     current, RelationGetRelationName(state->rel))));
 
                 if (level.istruerootlevel && !P_ISROOT(opaque))
                     ereport(ERROR,
                             (errcode(ERRCODE_INDEX_CORRUPTED),
                              errmsg("block %u is not true root in index \"%s\"",
                                     current, RelationGetRelationName(state->rel))));
             }
 
             /*
              * Before beginning any non-trivial examination of level, prepare
              * state for next bt_check_level_from_leftmost() invocation for
              * the next level for the next level down (if any).
              *
              * There should be at least one non-ignorable page per level,
              * unless this is the leaf level, which is assumed by caller to be
              * final level.
              */
             if (!P_ISLEAF(opaque))
             {
                 IndexTuple  itup;
                 ItemId      itemid;
 
                 /* Internal page -- downlink gets leftmost on next level */
                 itemid = PageGetItemIdCareful(state, state->targetblock,
                                               state->target,
                                               P_FIRSTDATAKEY(opaque));
                 itup = (IndexTuple) PageGetItem(state->target, itemid);
                 nextleveldown.leftmost = BTreeInnerTupleGetDownLink(itup);
                 nextleveldown.level = opaque->btpo.level - 1;
             }
             else
             {
                 /*
                  * Leaf page -- final level caller must process.
                  *
                  * Note that this could also be the root page, if there has
                  * been no root page split yet.
                  */
                 nextleveldown.leftmost = P_NONE;
                 nextleveldown.level = InvalidBtreeLevel;
             }
 
             /*
              * Finished setting up state for this call/level.  Control will
              * never end up back here in any future loop iteration for this
              * level.
              */
         }
 
         /*
          * readonly mode can only ever land on live pages and half-dead pages,
          * so sibling pointers should always be in mutual agreement
          */
         if (state->readonly && opaque->btpo_prev != leftcurrent)
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("left link/right link pair in index \"%s\" not in agreement",
                             RelationGetRelationName(state->rel)),
                      errdetail_internal("Block=%u left block=%u left link from block=%u.",
                                         current, leftcurrent, opaque->btpo_prev)));
 
         /* Check level, which must be valid for non-ignorable page */
         if (level.level != opaque->btpo.level)
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("leftmost down link for level points to block in index \"%s\" whose level is not one level down",
                             RelationGetRelationName(state->rel)),
                      errdetail_internal("Block pointed to=%u expected level=%u level in pointed to block=%u.",
                                         current, level.level, opaque->btpo.level)));
 
         /* Verify invariants for page */
         bt_target_page_check(state);
 
 nextpage:
 
         /* Try to detect circular links */
         if (current == leftcurrent || current == opaque->btpo_prev)
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("circular link chain found in block %u of index \"%s\"",
                             current, RelationGetRelationName(state->rel))));
 
         /*
          * Record if page that is about to become target is the right half of
          * an incomplete page split.  This can go stale immediately in
          * !readonly case.
          */
         state->rightsplit = P_INCOMPLETE_SPLIT(opaque);
 
         leftcurrent = current;
         current = opaque->btpo_next;
 
         /* Free page and associated memory for this iteration */
         MemoryContextReset(state->targetcontext);
     }
     while (current != P_NONE);
 
     /* Don't change context for caller */
     MemoryContextSwitchTo(oldcontext);
 
     return nextleveldown;
 }

◆ bt_downlink_check()

static void bt_downlink_check	(	BtreeCheckState *	state,
		BTScanInsert	targetkey,
		BlockNumber	childblock
	)

static

Definition at line 1509 of file verify_nbtree.c.

References Assert, ereport, errcode(), errdetail_internal(), errmsg(), ERROR, invariant_l_nontarget_offset(), offset_is_negative_infinity(), OffsetNumberNext, P_FIRSTDATAKEY, P_ISDELETED, PageGetMaxOffsetNumber, PageGetSpecialPointer, palloc_btree_page(), pfree(), BtreeCheckState::readonly, BtreeCheckState::rel, RelationGetRelationName, BtreeCheckState::targetblock, and BtreeCheckState::targetlsn.

Referenced by bt_target_page_check().

 {
     OffsetNumber offset;
     OffsetNumber maxoffset;
     Page        child;
     BTPageOpaque copaque;
 
     /*
      * Caller must have ShareLock on target relation, because of
      * considerations around page deletion by VACUUM.
      *
      * NB: In general, page deletion deletes the right sibling's downlink, not
      * the downlink of the page being deleted; the deleted page's downlink is
      * reused for its sibling.  The key space is thereby consolidated between
      * the deleted page and its right sibling.  (We cannot delete a parent
      * page's rightmost child unless it is the last child page, and we intend
      * to also delete the parent itself.)
      *
      * If this verification happened without a ShareLock, the following race
      * condition could cause false positives:
      *
      * In general, concurrent page deletion might occur, including deletion of
      * the left sibling of the child page that is examined here.  If such a
      * page deletion were to occur, closely followed by an insertion into the
      * newly expanded key space of the child, a window for the false positive
      * opens up: the stale parent/target downlink originally followed to get
      * to the child legitimately ceases to be a lower bound on all items in
      * the page, since the key space was concurrently expanded "left".
      * (Insertion followed the "new" downlink for the child, not our now-stale
      * downlink, which was concurrently physically removed in target/parent as
      * part of deletion's first phase.)
      *
      * Note that while the cross-page-same-level last item check uses a trick
      * that allows it to perform verification for !readonly callers, a similar
      * trick seems difficult here.  The trick that that other check uses is,
      * in essence, to lock down race conditions to those that occur due to
      * concurrent page deletion of the target; that's a race that can be
      * reliably detected before actually reporting corruption.
      *
      * On the other hand, we'd need to lock down race conditions involving
      * deletion of child's left page, for long enough to read the child page
      * into memory (in other words, a scheme with concurrently held buffer
      * locks on both child and left-of-child pages).  That's unacceptable for
      * amcheck functions on general principle, though.
      */
     Assert(state->readonly);
 
     /*
      * Verify child page has the downlink key from target page (its parent) as
      * a lower bound; downlink must be strictly less than all keys on the
      * page.
      *
      * Check all items, rather than checking just the first and trusting that
      * the operator class obeys the transitive law.
      */
     child = palloc_btree_page(state, childblock);
     copaque = (BTPageOpaque) PageGetSpecialPointer(child);
     maxoffset = PageGetMaxOffsetNumber(child);
 
     /*
      * Since there cannot be a concurrent VACUUM operation in readonly mode,
      * and since a page has no links within other pages (siblings and parent)
      * once it is marked fully deleted, it should be impossible to land on a
      * fully deleted page.
      *
      * It does not quite make sense to enforce that the page cannot even be
      * half-dead, despite the fact the downlink is modified at the same stage
      * that the child leaf page is marked half-dead.  That's incorrect because
      * there may occasionally be multiple downlinks from a chain of pages
      * undergoing deletion, where multiple successive calls are made to
      * _bt_unlink_halfdead_page() by VACUUM before it can finally safely mark
      * the leaf page as fully dead.  While _bt_mark_page_halfdead() usually
      * removes the downlink to the leaf page that is marked half-dead, that's
      * not guaranteed, so it's possible we'll land on a half-dead page with a
      * downlink due to an interrupted multi-level page deletion.
      *
      * We go ahead with our checks if the child page is half-dead.  It's safe
      * to do so because we do not test the child's high key, so it does not
      * matter that the original high key will have been replaced by a dummy
      * truncated high key within _bt_mark_page_halfdead().  All other page
      * items are left intact on a half-dead page, so there is still something
      * to test.
      */
     if (P_ISDELETED(copaque))
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg("downlink to deleted page found in index \"%s\"",
                         RelationGetRelationName(state->rel)),
                  errdetail_internal("Parent block=%u child block=%u parent page lsn=%X/%X.",
                                     state->targetblock, childblock,
                                     (uint32) (state->targetlsn >> 32),
                                     (uint32) state->targetlsn)));
 
     for (offset = P_FIRSTDATAKEY(copaque);
          offset <= maxoffset;
          offset = OffsetNumberNext(offset))
     {
         /*
          * Skip comparison of target page key against "negative infinity"
          * item, if any.  Checking it would indicate that it's not a strict
          * lower bound, but that's only because of the hard-coding for
          * negative infinity items within _bt_compare().
          *
          * If nbtree didn't truncate negative infinity tuples during internal
          * page splits then we'd expect child's negative infinity key to be
          * equal to the scankey/downlink from target/parent (it would be a
          * "low key" in this hypothetical scenario, and so it would still need
          * to be treated as a special case here).
          *
          * Negative infinity items can be thought of as a strict lower bound
          * that works transitively, with the last non-negative-infinity pivot
          * followed during a descent from the root as its "true" strict lower
          * bound.  Only a small number of negative infinity items are truly
          * negative infinity; those that are the first items of leftmost
          * internal pages.  In more general terms, a negative infinity item is
          * only negative infinity with respect to the subtree that the page is
          * at the root of.
          *
          * See also: bt_rootdescend(), which can even detect transitive
          * inconsistencies on cousin leaf pages.
          */
         if (offset_is_negative_infinity(copaque, offset))
             continue;
 
         if (!invariant_l_nontarget_offset(state, targetkey, childblock, child,
                                           offset))
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("down-link lower bound invariant violated for index \"%s\"",
                             RelationGetRelationName(state->rel)),
                      errdetail_internal("Parent block=%u child index tid=(%u,%u) parent page lsn=%X/%X.",
                                         state->targetblock, childblock, offset,
                                         (uint32) (state->targetlsn >> 32),
                                         (uint32) state->targetlsn)));
     }
 
     pfree(child);
 }

◆ bt_downlink_missing_check()

static void bt_downlink_missing_check ( BtreeCheckState * state )

static

Definition at line 1663 of file verify_nbtree.c.

References Assert, bloom_lacks_element(), BTPageOpaqueData::btpo, BTPageOpaqueData::btpo_prev, BTreeInnerTupleGetDownLink, BTreeTupleGetTopParent, CHECK_FOR_INTERRUPTS, DEBUG1, BtreeCheckState::downlinkfilter, elog, ereport, errcode(), errdetail_internal(), errmsg(), errmsg_internal(), ERROR, BtreeCheckState::heapallindexed, BTPageOpaqueData::level, P_FIRSTDATAKEY, P_HIKEY, P_IGNORE, P_ISDELETED, P_ISHALFDEAD, P_ISLEAF, P_ISROOT, P_RIGHTMOST, PageGetItem, PageGetItemIdCareful(), PageGetSpecialPointer, palloc_btree_page(), pfree(), BtreeCheckState::readonly, BtreeCheckState::rel, RelationGetRelationName, BtreeCheckState::rightsplit, BtreeCheckState::target, BtreeCheckState::targetblock, and BtreeCheckState::targetlsn.

Referenced by bt_target_page_check().

 {
     BTPageOpaque topaque = (BTPageOpaque) PageGetSpecialPointer(state->target);
     ItemId      itemid;
     IndexTuple  itup;
     Page        child;
     BTPageOpaque copaque;
     uint32      level;
     BlockNumber childblk;
 
     Assert(state->heapallindexed && state->readonly);
     Assert(!P_IGNORE(topaque));
 
     /* No next level up with downlinks to fingerprint from the true root */
     if (P_ISROOT(topaque))
         return;
 
     /*
      * Incomplete (interrupted) page splits can account for the lack of a
      * downlink.  Some inserting transaction should eventually complete the
      * page split in passing, when it notices that the left sibling page is
      * P_INCOMPLETE_SPLIT().
      *
      * In general, VACUUM is not prepared for there to be no downlink to a
      * page that it deletes.  This is the main reason why the lack of a
      * downlink can be reported as corruption here.  It's not obvious that an
      * invalid missing downlink can result in wrong answers to queries,
      * though, since index scans that land on the child may end up
      * consistently moving right. The handling of concurrent page splits (and
      * page deletions) within _bt_moveright() cannot distinguish
      * inconsistencies that last for a moment from inconsistencies that are
      * permanent and irrecoverable.
      *
      * VACUUM isn't even prepared to delete pages that have no downlink due to
      * an incomplete page split, but it can detect and reason about that case
      * by design, so it shouldn't be taken to indicate corruption.  See
      * _bt_pagedel() for full details.
      */
     if (state->rightsplit)
     {
         ereport(DEBUG1,
                 (errcode(ERRCODE_NO_DATA),
                  errmsg("harmless interrupted page split detected in index %s",
                         RelationGetRelationName(state->rel)),
                  errdetail_internal("Block=%u level=%u left sibling=%u page lsn=%X/%X.",
                                     state->targetblock, topaque->btpo.level,
                                     topaque->btpo_prev,
                                     (uint32) (state->targetlsn >> 32),
                                     (uint32) state->targetlsn)));
         return;
     }
 
     /* Target's downlink is typically present in parent/fingerprinted */
     if (!bloom_lacks_element(state->downlinkfilter,
                              (unsigned char *) &state->targetblock,
                              sizeof(BlockNumber)))
         return;
 
     /*
      * Target is probably the "top parent" of a multi-level page deletion.
      * We'll need to descend the subtree to make sure that descendant pages
      * are consistent with that, though.
      *
      * If the target page (which must be non-ignorable) is a leaf page, then
      * clearly it can't be the top parent.  The lack of a downlink is probably
      * a symptom of a broad problem that could just as easily cause
      * inconsistencies anywhere else.
      */
     if (P_ISLEAF(topaque))
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg("leaf index block lacks downlink in index \"%s\"",
                         RelationGetRelationName(state->rel)),
                  errdetail_internal("Block=%u page lsn=%X/%X.",
                                     state->targetblock,
                                     (uint32) (state->targetlsn >> 32),
                                     (uint32) state->targetlsn)));
 
     /* Descend from the target page, which is an internal page */
     elog(DEBUG1, "checking for interrupted multi-level deletion due to missing downlink in index \"%s\"",
          RelationGetRelationName(state->rel));
 
     level = topaque->btpo.level;
     itemid = PageGetItemIdCareful(state, state->targetblock, state->target,
                                   P_FIRSTDATAKEY(topaque));
     itup = (IndexTuple) PageGetItem(state->target, itemid);
     childblk = BTreeInnerTupleGetDownLink(itup);
     for (;;)
     {
         CHECK_FOR_INTERRUPTS();
 
         child = palloc_btree_page(state, childblk);
         copaque = (BTPageOpaque) PageGetSpecialPointer(child);
 
         if (P_ISLEAF(copaque))
             break;
 
         /* Do an extra sanity check in passing on internal pages */
         if (copaque->btpo.level != level - 1)
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg_internal("downlink points to block in index \"%s\" whose level is not one level down",
                                      RelationGetRelationName(state->rel)),
                      errdetail_internal("Top parent/target block=%u block pointed to=%u expected level=%u level in pointed to block=%u.",
                                         state->targetblock, childblk,
                                         level - 1, copaque->btpo.level)));
 
         level = copaque->btpo.level;
         itemid = PageGetItemIdCareful(state, childblk, child,
                                       P_FIRSTDATAKEY(copaque));
         itup = (IndexTuple) PageGetItem(child, itemid);
         childblk = BTreeInnerTupleGetDownLink(itup);
         /* Be slightly more pro-active in freeing this memory, just in case */
         pfree(child);
     }
 
     /*
      * Since there cannot be a concurrent VACUUM operation in readonly mode,
      * and since a page has no links within other pages (siblings and parent)
      * once it is marked fully deleted, it should be impossible to land on a
      * fully deleted page.  See bt_downlink_check() for further details.
      *
      * The bt_downlink_check() P_ISDELETED() check is repeated here because
      * bt_downlink_check() does not visit pages reachable through negative
      * infinity items.  Besides, bt_downlink_check() is unwilling to descend
      * multiple levels.  (The similar bt_downlink_check() P_ISDELETED() check
      * within bt_check_level_from_leftmost() won't reach the page either,
      * since the leaf's live siblings should have their sibling links updated
      * to bypass the deletion target page when it is marked fully dead.)
      *
      * If this error is raised, it might be due to a previous multi-level page
      * deletion that failed to realize that it wasn't yet safe to mark the
      * leaf page as fully dead.  A "dangling downlink" will still remain when
      * this happens.  The fact that the dangling downlink's page (the leaf's
      * parent/ancestor page) lacked a downlink is incidental.
      */
     if (P_ISDELETED(copaque))
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg_internal("downlink to deleted leaf page found in index \"%s\"",
                                  RelationGetRelationName(state->rel)),
                  errdetail_internal("Top parent/target block=%u leaf block=%u top parent/target lsn=%X/%X.",
                                     state->targetblock, childblk,
                                     (uint32) (state->targetlsn >> 32),
                                     (uint32) state->targetlsn)));
 
     /*
      * Iff leaf page is half-dead, its high key top parent link should point
      * to what VACUUM considered to be the top parent page at the instant it
      * was interrupted.  Provided the high key link actually points to the
      * target page, the missing downlink we detected is consistent with there
      * having been an interrupted multi-level page deletion.  This means that
      * the subtree with the target page at its root (a page deletion chain) is
      * in a consistent state, enabling VACUUM to resume deleting the entire
      * chain the next time it encounters the half-dead leaf page.
      */
     if (P_ISHALFDEAD(copaque) && !P_RIGHTMOST(copaque))
     {
         itemid = PageGetItemIdCareful(state, childblk, child, P_HIKEY);
         itup = (IndexTuple) PageGetItem(child, itemid);
         if (BTreeTupleGetTopParent(itup) == state->targetblock)
             return;
     }
 
     ereport(ERROR,
             (errcode(ERRCODE_INDEX_CORRUPTED),
              errmsg("internal index block lacks downlink in index \"%s\"",
                     RelationGetRelationName(state->rel)),
              errdetail_internal("Block=%u level=%u page lsn=%X/%X.",
                                 state->targetblock, topaque->btpo.level,
                                 (uint32) (state->targetlsn >> 32),
                                 (uint32) state->targetlsn)));
 }

◆ bt_index_check()

Datum bt_index_check ( PG_FUNCTION_ARGS )

Definition at line 181 of file verify_nbtree.c.

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

 {
     Oid         indrelid = PG_GETARG_OID(0);
     bool        heapallindexed = false;
 
     if (PG_NARGS() == 2)
         heapallindexed = PG_GETARG_BOOL(1);
 
     bt_index_check_internal(indrelid, false, heapallindexed, false);
 
     PG_RETURN_VOID();
 }

◆ bt_index_check_internal()

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

static

Definition at line 224 of file verify_nbtree.c.

References _bt_heapkeyspace(), 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().

 {
     Oid         heapid;
     Relation    indrel;
     Relation    heaprel;
     LOCKMODE    lockmode;
 
     if (parentcheck)
         lockmode = ShareLock;
     else
         lockmode = AccessShareLock;
 
     /*
      * We must lock table before index to avoid deadlocks.  However, if the
      * passed indrelid isn't an index then IndexGetRelation() will fail.
      * Rather than emitting a not-very-helpful error message, postpone
      * complaining, expecting that the is-it-an-index test below will fail.
      *
      * In hot standby mode this will raise an error when parentcheck is true.
      */
     heapid = IndexGetRelation(indrelid, true);
     if (OidIsValid(heapid))
         heaprel = table_open(heapid, lockmode);
     else
         heaprel = NULL;
 
     /*
      * Open the target index relations separately (like relation_openrv(), but
      * with heap relation locked first to prevent deadlocking).  In hot
      * standby mode this will raise an error when parentcheck is true.
      *
      * There is no need for the usual indcheckxmin usability horizon test
      * here, even in the heapallindexed case, because index undergoing
      * verification only needs to have entries for a new transaction snapshot.
      * (If this is a parentcheck verification, there is no question about
      * committed or recently dead heap tuples lacking index entries due to
      * concurrent activity.)
      */
     indrel = index_open(indrelid, lockmode);
 
     /*
      * Since we did the IndexGetRelation call above without any lock, it's
      * barely possible that a race against an index drop/recreation could have
      * netted us the wrong table.
      */
     if (heaprel == NULL || heapid != IndexGetRelation(indrelid, false))
         ereport(ERROR,
                 (errcode(ERRCODE_UNDEFINED_TABLE),
                  errmsg("could not open parent table of index %s",
                         RelationGetRelationName(indrel))));
 
     /* Relation suitable for checking as B-Tree? */
     btree_index_checkable(indrel);
 
     if (btree_index_mainfork_expected(indrel))
     {
         bool    heapkeyspace;
 
         RelationOpenSmgr(indrel);
         if (!smgrexists(indrel->rd_smgr, MAIN_FORKNUM))
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("index \"%s\" lacks a main relation fork",
                             RelationGetRelationName(indrel))));
 
         /* Check index, possibly against table it is an index on */
         heapkeyspace = _bt_heapkeyspace(indrel);
         bt_check_every_level(indrel, heaprel, heapkeyspace, parentcheck,
                              heapallindexed, rootdescend);
     }
 
     /*
      * Release locks early. That's ok here because nothing in the called
      * routines will trigger shared cache invalidations to be sent, so we can
      * relax the usual pattern of only releasing locks after commit.
      */
     index_close(indrel, lockmode);
     if (heaprel)
         table_close(heaprel, lockmode);
 }

◆ bt_index_parent_check()

Datum bt_index_parent_check ( PG_FUNCTION_ARGS )

Definition at line 204 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.

 {
     Oid         indrelid = PG_GETARG_OID(0);
     bool        heapallindexed = false;
     bool        rootdescend = false;
 
     if (PG_NARGS() >= 2)
         heapallindexed = PG_GETARG_BOOL(1);
     if (PG_NARGS() == 3)
         rootdescend = PG_GETARG_BOOL(2);
 
     bt_index_check_internal(indrelid, true, heapallindexed, rootdescend);
 
     PG_RETURN_VOID();
 }

◆ bt_mkscankey_pivotsearch()

static BTScanInsert bt_mkscankey_pivotsearch	(	Relation	rel,
		IndexTuple	itup
	)

inlinestatic

Definition at line 2491 of file verify_nbtree.c.

References _bt_mkscankey(), and BTScanInsertData::pivotsearch.

Referenced by bt_right_page_check_scankey(), and bt_target_page_check().

 {
     BTScanInsert skey;
 
     skey = _bt_mkscankey(rel, itup);
     skey->pivotsearch = true;
 
     return skey;
 }

◆ bt_normalize_tuple()

static IndexTuple bt_normalize_tuple	(	BtreeCheckState *	state,
		IndexTuple	itup
	)

static

Definition at line 1962 of file verify_nbtree.c.

References 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().

 {
     TupleDesc   tupleDescriptor = RelationGetDescr(state->rel);
     Datum       normalized[INDEX_MAX_KEYS];
     bool        isnull[INDEX_MAX_KEYS];
     bool        toast_free[INDEX_MAX_KEYS];
     bool        formnewtup = false;
     IndexTuple  reformed;
     int         i;
 
     /* Easy case: It's immediately clear that tuple has no varlena datums */
     if (!IndexTupleHasVarwidths(itup))
         return itup;
 
     for (i = 0; i < tupleDescriptor->natts; i++)
     {
         Form_pg_attribute att;
 
         att = TupleDescAttr(tupleDescriptor, i);
 
         /* Assume untoasted/already normalized datum initially */
         toast_free[i] = false;
         normalized[i] = index_getattr(itup, att->attnum,
                                       tupleDescriptor,
                                       &isnull[i]);
         if (att->attbyval || att->attlen != -1 || isnull[i])
             continue;
 
         /*
          * Callers always pass a tuple that could safely be inserted into the
          * index without further processing, so an external varlena header
          * should never be encountered here
          */
         if (VARATT_IS_EXTERNAL(DatumGetPointer(normalized[i])))
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("external varlena datum in tuple that references heap row (%u,%u) in index \"%s\"",
                             ItemPointerGetBlockNumber(&(itup->t_tid)),
                             ItemPointerGetOffsetNumber(&(itup->t_tid)),
                             RelationGetRelationName(state->rel))));
         else if (VARATT_IS_COMPRESSED(DatumGetPointer(normalized[i])))
         {
             formnewtup = true;
             normalized[i] = PointerGetDatum(PG_DETOAST_DATUM(normalized[i]));
             toast_free[i] = true;
         }
     }
 
     /* Easier case: Tuple has varlena datums, none of which are compressed */
     if (!formnewtup)
         return itup;
 
     /*
      * Hard case: Tuple had compressed varlena datums that necessitate
      * creating normalized version of the tuple from uncompressed input datums
      * (normalized input datums).  This is rather naive, but shouldn't be
      * necessary too often.
      *
      * Note that we rely on deterministic index_form_tuple() TOAST compression
      * of normalized input.
      */
     reformed = index_form_tuple(tupleDescriptor, normalized, isnull);
     reformed->t_tid = itup->t_tid;
 
     /* Cannot leak memory here */
     for (i = 0; i < tupleDescriptor->natts; i++)
         if (toast_free[i])
             pfree(DatumGetPointer(normalized[i]));
 
     return reformed;
 }

◆ bt_right_page_check_scankey()

static BTScanInsert bt_right_page_check_scankey ( BtreeCheckState * state )

static

Definition at line 1302 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().

 {
     BTPageOpaque opaque;
     ItemId      rightitem;
     IndexTuple  firstitup;
     BlockNumber targetnext;
     Page        rightpage;
     OffsetNumber nline;
 
     /* Determine target's next block number */
     opaque = (BTPageOpaque) PageGetSpecialPointer(state->target);
 
     /* If target is already rightmost, no right sibling; nothing to do here */
     if (P_RIGHTMOST(opaque))
         return NULL;
 
     /*
      * General notes on concurrent page splits and page deletion:
      *
      * Routines like _bt_search() don't require *any* page split interlock
      * when descending the tree, including something very light like a buffer
      * pin. That's why it's okay that we don't either.  This avoidance of any
      * need to "couple" buffer locks is the raison d' etre of the Lehman & Yao
      * algorithm, in fact.
      *
      * That leaves deletion.  A deleted page won't actually be recycled by
      * VACUUM early enough for us to fail to at least follow its right link
      * (or left link, or downlink) and find its sibling, because recycling
      * does not occur until no possible index scan could land on the page.
      * Index scans can follow links with nothing more than their snapshot as
      * an interlock and be sure of at least that much.  (See page
      * recycling/RecentGlobalXmin notes in nbtree README.)
      *
      * Furthermore, it's okay if we follow a rightlink and find a half-dead or
      * dead (ignorable) page one or more times.  There will either be a
      * further right link to follow that leads to a live page before too long
      * (before passing by parent's rightmost child), or we will find the end
      * of the entire level instead (possible when parent page is itself the
      * rightmost on its level).
      */
     targetnext = opaque->btpo_next;
     for (;;)
     {
         CHECK_FOR_INTERRUPTS();
 
         rightpage = palloc_btree_page(state, targetnext);
         opaque = (BTPageOpaque) PageGetSpecialPointer(rightpage);
 
         if (!P_IGNORE(opaque) || P_RIGHTMOST(opaque))
             break;
 
         /* We landed on a deleted page, so step right to find a live page */
         targetnext = opaque->btpo_next;
         ereport(DEBUG1,
                 (errcode(ERRCODE_NO_DATA),
                  errmsg("level %u leftmost page of index \"%s\" was found deleted or half dead",
                         opaque->btpo.level, RelationGetRelationName(state->rel)),
                  errdetail_internal("Deleted page found when building scankey from right sibling.")));
 
         /* Be slightly more pro-active in freeing this memory, just in case */
         pfree(rightpage);
     }
 
     /*
      * No ShareLock held case -- why it's safe to proceed.
      *
      * Problem:
      *
      * We must avoid false positive reports of corruption when caller treats
      * item returned here as an upper bound on target's last item.  In
      * general, false positives are disallowed.  Avoiding them here when
      * caller is !readonly is subtle.
      *
      * A concurrent page deletion by VACUUM of the target page can result in
      * the insertion of items on to this right sibling page that would
      * previously have been inserted on our target page.  There might have
      * been insertions that followed the target's downlink after it was made
      * to point to right sibling instead of target by page deletion's first
      * phase. The inserters insert items that would belong on target page.
      * This race is very tight, but it's possible.  This is our only problem.
      *
      * Non-problems:
      *
      * We are not hindered by a concurrent page split of the target; we'll
      * never land on the second half of the page anyway.  A concurrent split
      * of the right page will also not matter, because the first data item
      * remains the same within the left half, which we'll reliably land on. If
      * we had to skip over ignorable/deleted pages, it cannot matter because
      * their key space has already been atomically merged with the first
      * non-ignorable page we eventually find (doesn't matter whether the page
      * we eventually find is a true sibling or a cousin of target, which we go
      * into below).
      *
      * Solution:
      *
      * Caller knows that it should reverify that target is not ignorable
      * (half-dead or deleted) when cross-page sibling item comparison appears
      * to indicate corruption (invariant fails).  This detects the single race
      * condition that exists for caller.  This is correct because the
      * continued existence of target block as non-ignorable (not half-dead or
      * deleted) implies that target page was not merged into from the right by
      * deletion; the key space at or after target never moved left.  Target's
      * parent either has the same downlink to target as before, or a <
      * downlink due to deletion at the left of target.  Target either has the
      * same highkey as before, or a highkey < before when there is a page
      * split. (The rightmost concurrently-split-from-target-page page will
      * still have the same highkey as target was originally found to have,
      * which for our purposes is equivalent to target's highkey itself never
      * changing, since we reliably skip over
      * concurrently-split-from-target-page pages.)
      *
      * In simpler terms, we allow that the key space of the target may expand
      * left (the key space can move left on the left side of target only), but
      * the target key space cannot expand right and get ahead of us without
      * our detecting it.  The key space of the target cannot shrink, unless it
      * shrinks to zero due to the deletion of the original page, our canary
      * condition.  (To be very precise, we're a bit stricter than that because
      * it might just have been that the target page split and only the
      * original target page was deleted.  We can be more strict, just not more
      * lax.)
      *
      * Top level tree walk caller moves on to next page (makes it the new
      * target) following recovery from this race.  (cf.  The rationale for
      * child/downlink verification needing a ShareLock within
      * bt_downlink_check(), where page deletion is also the main source of
      * trouble.)
      *
      * Note that it doesn't matter if right sibling page here is actually a
      * cousin page, because in order for the key space to be readjusted in a
      * way that causes us issues in next level up (guiding problematic
      * concurrent insertions to the cousin from the grandparent rather than to
      * the sibling from the parent), there'd have to be page deletion of
      * target's parent page (affecting target's parent's downlink in target's
      * grandparent page).  Internal page deletion only occurs when there are
      * no child pages (they were all fully deleted), and caller is checking
      * that the target's parent has at least one non-deleted (so
      * non-ignorable) child: the target page.  (Note that the first phase of
      * deletion atomically marks the page to be deleted half-dead/ignorable at
      * the same time downlink in its parent is removed, so caller will
      * definitely not fail to detect that this happened.)
      *
      * This trick is inspired by the method backward scans use for dealing
      * with concurrent page splits; concurrent page deletion is a problem that
      * similarly receives special consideration sometimes (it's possible that
      * the backwards scan will re-read its "original" block after failing to
      * find a right-link to it, having already moved in the opposite direction
      * (right/"forwards") a few times to try to locate one).  Just like us,
      * that happens only to determine if there was a concurrent page deletion
      * of a reference page, and just like us if there was a page deletion of
      * that reference page it means we can move on from caring about the
      * reference page.  See the nbtree README for a full description of how
      * that works.
      */
     nline = PageGetMaxOffsetNumber(rightpage);
 
     /*
      * Get first data item, if any
      */
     if (P_ISLEAF(opaque) && nline >= P_FIRSTDATAKEY(opaque))
     {
         /* Return first data item (if any) */
         rightitem = PageGetItemIdCareful(state, targetnext, rightpage,
                                          P_FIRSTDATAKEY(opaque));
     }
     else if (!P_ISLEAF(opaque) &&
              nline >= OffsetNumberNext(P_FIRSTDATAKEY(opaque)))
     {
         /*
          * Return first item after the internal page's "negative infinity"
          * item
          */
         rightitem = PageGetItemIdCareful(state, targetnext, rightpage,
                                          OffsetNumberNext(P_FIRSTDATAKEY(opaque)));
     }
     else
     {
         /*
          * No first item.  Page is probably empty leaf page, but it's also
          * possible that it's an internal page with only a negative infinity
          * item.
          */
         ereport(DEBUG1,
                 (errcode(ERRCODE_NO_DATA),
                  errmsg("%s block %u of index \"%s\" has no first data item",
                         P_ISLEAF(opaque) ? "leaf" : "internal", targetnext,
                         RelationGetRelationName(state->rel))));
         return NULL;
     }
 
     /*
      * Return first real item scankey.  Note that this relies on right page
      * memory remaining allocated.
      */
     firstitup = (IndexTuple) PageGetItem(rightpage, rightitem);
     return bt_mkscankey_pivotsearch(state->rel, firstitup);
 }

◆ bt_rootdescend()

static bool bt_rootdescend	(	BtreeCheckState *	state,
		IndexTuple	itup
	)

static

Definition at line 2059 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(), BtreeCheckState::readonly, BtreeCheckState::rel, BtreeCheckState::rootdescend, and BTScanInsertData::scantid.

Referenced by bt_target_page_check().

 {
     BTScanInsert key;
     BTStack     stack;
     Buffer      lbuf;
     bool        exists;
 
     key = _bt_mkscankey(state->rel, itup);
     Assert(key->heapkeyspace && key->scantid != NULL);
 
     /*
      * Search from root.
      *
      * Ideally, we would arrange to only move right within _bt_search() when
      * an interrupted page split is detected (i.e. when the incomplete split
      * bit is found to be set), but for now we accept the possibility that
      * that could conceal an inconsistency.
      */
     Assert(state->readonly && state->rootdescend);
     exists = false;
     stack = _bt_search(state->rel, key, &lbuf, BT_READ, NULL);
 
     if (BufferIsValid(lbuf))
     {
         BTInsertStateData insertstate;
         OffsetNumber offnum;
         Page        page;
 
         insertstate.itup = itup;
         insertstate.itemsz = MAXALIGN(IndexTupleSize(itup));
         insertstate.itup_key = key;
         insertstate.bounds_valid = false;
         insertstate.buf = lbuf;
 
         /* Get matching tuple on leaf page */
         offnum = _bt_binsrch_insert(state->rel, &insertstate);
         /* Compare first >= matching item on leaf page, if any */
         page = BufferGetPage(lbuf);
         if (offnum <= PageGetMaxOffsetNumber(page) &&
             _bt_compare(state->rel, key, page, offnum) == 0)
             exists = true;
         _bt_relbuf(state->rel, lbuf);
     }
 
     _bt_freestack(stack);
     pfree(key);
 
     return exists;
 }

◆ bt_target_page_check()

static void bt_target_page_check ( BtreeCheckState * state )

static

Definition at line 872 of file verify_nbtree.c.

References _bt_check_natts(), bloom_add_element(), bt_downlink_check(), bt_downlink_missing_check(), bt_mkscankey_pivotsearch(), bt_normalize_tuple(), bt_right_page_check_scankey(), bt_rootdescend(), BTMaxItemSize, BTMaxItemSizeNoHeapTid, BTreeInnerTupleGetDownLink, BTreeTupleGetHeapTID, BTreeTupleGetNAtts, CHECK_FOR_INTERRUPTS, DEBUG2, BtreeCheckState::downlinkfilter, elog, ereport, errcode(), errdetail_internal(), errhint(), errmsg(), ERROR, BtreeCheckState::filter, BtreeCheckState::heapallindexed, BtreeCheckState::heapkeyspace, BTScanInsertData::heapkeyspace, IndexTupleSize, invariant_g_offset(), invariant_l_offset(), invariant_leq_offset(), ItemIdGetLength, ItemIdIsDead, ItemPointerGetBlockNumber, ItemPointerGetBlockNumberNoCheck, ItemPointerGetOffsetNumber, ItemPointerGetOffsetNumberNoCheck, 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, IndexTupleData::t_tid, BtreeCheckState::target, BtreeCheckState::targetblock, and BtreeCheckState::targetlsn.

Referenced by bt_check_level_from_leftmost().

 {
     OffsetNumber offset;
     OffsetNumber max;
     BTPageOpaque topaque;
 
     topaque = (BTPageOpaque) PageGetSpecialPointer(state->target);
     max = PageGetMaxOffsetNumber(state->target);
 
     elog(DEBUG2, "verifying %u items on %s block %u", max,
          P_ISLEAF(topaque) ? "leaf" : "internal", state->targetblock);
 
     /*
      * Check the number of attributes in high key. Note, rightmost page
      * doesn't contain a high key, so nothing to check
      */
     if (!P_RIGHTMOST(topaque))
     {
         ItemId      itemid;
         IndexTuple  itup;
 
         /* Verify line pointer before checking tuple */
         itemid = PageGetItemIdCareful(state, state->targetblock,
                                       state->target, P_HIKEY);
         if (!_bt_check_natts(state->rel, state->heapkeyspace, state->target,
                              P_HIKEY))
         {
             itup = (IndexTuple) PageGetItem(state->target, itemid);
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("wrong number of high key index tuple attributes in index \"%s\"",
                             RelationGetRelationName(state->rel)),
                      errdetail_internal("Index block=%u natts=%u block type=%s page lsn=%X/%X.",
                                         state->targetblock,
                                         BTreeTupleGetNAtts(itup, state->rel),
                                         P_ISLEAF(topaque) ? "heap" : "index",
                                         (uint32) (state->targetlsn >> 32),
                                         (uint32) state->targetlsn)));
         }
     }
 
     /*
      * Loop over page items, starting from first non-highkey item, not high
      * key (if any).  Most tests are not performed for the "negative infinity"
      * real item (if any).
      */
     for (offset = P_FIRSTDATAKEY(topaque);
          offset <= max;
          offset = OffsetNumberNext(offset))
     {
         ItemId      itemid;
         IndexTuple  itup;
         size_t      tupsize;
         BTScanInsert skey;
         bool        lowersizelimit;
 
         CHECK_FOR_INTERRUPTS();
 
         itemid = PageGetItemIdCareful(state, state->targetblock,
                                       state->target, offset);
         itup = (IndexTuple) PageGetItem(state->target, itemid);
         tupsize = IndexTupleSize(itup);
 
         /*
          * lp_len should match the IndexTuple reported length exactly, since
          * lp_len is completely redundant in indexes, and both sources of
          * tuple length are MAXALIGN()'d.  nbtree does not use lp_len all that
          * frequently, and is surprisingly tolerant of corrupt lp_len fields.
          */
         if (tupsize != ItemIdGetLength(itemid))
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("index tuple size does not equal lp_len in index \"%s\"",
                             RelationGetRelationName(state->rel)),
                      errdetail_internal("Index tid=(%u,%u) tuple size=%zu lp_len=%u page lsn=%X/%X.",
                                         state->targetblock, offset,
                                         tupsize, ItemIdGetLength(itemid),
                                         (uint32) (state->targetlsn >> 32),
                                         (uint32) state->targetlsn),
                      errhint("This could be a torn page problem.")));
 
         /* Check the number of index tuple attributes */
         if (!_bt_check_natts(state->rel, state->heapkeyspace, state->target,
                              offset))
         {
             char       *itid,
                        *htid;
 
             itid = psprintf("(%u,%u)", state->targetblock, offset);
             htid = psprintf("(%u,%u)",
                             ItemPointerGetBlockNumberNoCheck(&(itup->t_tid)),
                             ItemPointerGetOffsetNumberNoCheck(&(itup->t_tid)));
 
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("wrong number of index tuple attributes in index \"%s\"",
                             RelationGetRelationName(state->rel)),
                      errdetail_internal("Index tid=%s natts=%u points to %s tid=%s page lsn=%X/%X.",
                                         itid,
                                         BTreeTupleGetNAtts(itup, state->rel),
                                         P_ISLEAF(topaque) ? "heap" : "index",
                                         htid,
                                         (uint32) (state->targetlsn >> 32),
                                         (uint32) state->targetlsn)));
         }
 
         /* Fingerprint downlink blocks in heapallindexed + readonly case */
         if (state->heapallindexed && state->readonly && !P_ISLEAF(topaque))
         {
             BlockNumber childblock = BTreeInnerTupleGetDownLink(itup);
 
             bloom_add_element(state->downlinkfilter,
                               (unsigned char *) &childblock,
                               sizeof(BlockNumber));
         }
 
         /*
          * Don't try to generate scankey using "negative infinity" item on
          * internal pages. They are always truncated to zero attributes.
          */
         if (offset_is_negative_infinity(topaque, offset))
             continue;
 
         /*
          * Readonly callers may optionally verify that non-pivot tuples can
          * each be found by an independent search that starts from the root
          */
         if (state->rootdescend && P_ISLEAF(topaque) &&
             !bt_rootdescend(state, itup))
         {
             char       *itid,
                        *htid;
 
             itid = psprintf("(%u,%u)", state->targetblock, offset);
             htid = psprintf("(%u,%u)",
                             ItemPointerGetBlockNumber(&(itup->t_tid)),
                             ItemPointerGetOffsetNumber(&(itup->t_tid)));
 
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("could not find tuple using search from root page in index \"%s\"",
                             RelationGetRelationName(state->rel)),
                      errdetail_internal("Index tid=%s points to heap tid=%s page lsn=%X/%X.",
                                         itid, htid,
                                         (uint32) (state->targetlsn >> 32),
                                         (uint32) state->targetlsn)));
         }
 
         /* Build insertion scankey for current page offset */
         skey = bt_mkscankey_pivotsearch(state->rel, itup);
 
         /*
          * Make sure tuple size does not exceed the relevant BTREE_VERSION
          * specific limit.
          *
          * BTREE_VERSION 4 (which introduced heapkeyspace rules) requisitioned
          * a small amount of space from BTMaxItemSize() in order to ensure
          * that suffix truncation always has enough space to add an explicit
          * heap TID back to a tuple -- we pessimistically assume that every
          * newly inserted tuple will eventually need to have a heap TID
          * appended during a future leaf page split, when the tuple becomes
          * the basis of the new high key (pivot tuple) for the leaf page.
          *
          * Since the reclaimed space is reserved for that purpose, we must not
          * enforce the slightly lower limit when the extra space has been used
          * as intended.  In other words, there is only a cross-version
          * difference in the limit on tuple size within leaf pages.
          *
          * Still, we're particular about the details within BTREE_VERSION 4
          * internal pages.  Pivot tuples may only use the extra space for its
          * designated purpose.  Enforce the lower limit for pivot tuples when
          * an explicit heap TID isn't actually present. (In all other cases
          * suffix truncation is guaranteed to generate a pivot tuple that's no
          * larger than the first right tuple provided to it by its caller.)
          */
         lowersizelimit = skey->heapkeyspace &&
             (P_ISLEAF(topaque) || BTreeTupleGetHeapTID(itup) == NULL);
         if (tupsize > (lowersizelimit ? BTMaxItemSize(state->target) :
                        BTMaxItemSizeNoHeapTid(state->target)))
         {
             char       *itid,
                        *htid;
 
             itid = psprintf("(%u,%u)", state->targetblock, offset);
             htid = psprintf("(%u,%u)",
                             ItemPointerGetBlockNumberNoCheck(&(itup->t_tid)),
                             ItemPointerGetOffsetNumberNoCheck(&(itup->t_tid)));
 
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("index row size %zu exceeds maximum for index \"%s\"",
                             tupsize, RelationGetRelationName(state->rel)),
                      errdetail_internal("Index tid=%s points to %s tid=%s page lsn=%X/%X.",
                                         itid,
                                         P_ISLEAF(topaque) ? "heap" : "index",
                                         htid,
                                         (uint32) (state->targetlsn >> 32),
                                         (uint32) state->targetlsn)));
         }
 
         /* Fingerprint leaf page tuples (those that point to the heap) */
         if (state->heapallindexed && P_ISLEAF(topaque) && !ItemIdIsDead(itemid))
         {
             IndexTuple  norm;
 
             norm = bt_normalize_tuple(state, itup);
             bloom_add_element(state->filter, (unsigned char *) norm,
                               IndexTupleSize(norm));
             /* Be tidy */
             if (norm != itup)
                 pfree(norm);
         }
 
         /*
          * * High key check *
          *
          * If there is a high key (if this is not the rightmost page on its
          * entire level), check that high key actually is upper bound on all
          * page items.
          *
          * We prefer to check all items against high key rather than checking
          * just the last and trusting that the operator class obeys the
          * transitive law (which implies that all previous items also
          * respected the high key invariant if they pass the item order
          * check).
          *
          * Ideally, we'd compare every item in the index against every other
          * item in the index, and not trust opclass obedience of the
          * transitive law to bridge the gap between children and their
          * grandparents (as well as great-grandparents, and so on).  We don't
          * go to those lengths because that would be prohibitively expensive,
          * and probably not markedly more effective in practice.
          *
          * On the leaf level, we check that the key is <= the highkey.
          * However, on non-leaf levels we check that the key is < the highkey,
          * because the high key is "just another separator" rather than a copy
          * of some existing key item; we expect it to be unique among all keys
          * on the same level.  (Suffix truncation will sometimes produce a
          * leaf highkey that is an untruncated copy of the lastleft item, but
          * never any other item, which necessitates weakening the leaf level
          * check to <=.)
          *
          * Full explanation for why a highkey is never truly a copy of another
          * item from the same level on internal levels:
          *
          * While the new left page's high key is copied from the first offset
          * on the right page during an internal page split, that's not the
          * full story.  In effect, internal pages are split in the middle of
          * the firstright tuple, not between the would-be lastleft and
          * firstright tuples: the firstright key ends up on the left side as
          * left's new highkey, and the firstright downlink ends up on the
          * right side as right's new "negative infinity" item.  The negative
          * infinity tuple is truncated to zero attributes, so we're only left
          * with the downlink.  In other words, the copying is just an
          * implementation detail of splitting in the middle of a (pivot)
          * tuple. (See also: "Notes About Data Representation" in the nbtree
          * README.)
          */
         if (!P_RIGHTMOST(topaque) &&
             !(P_ISLEAF(topaque) ? invariant_leq_offset(state, skey, P_HIKEY) :
               invariant_l_offset(state, skey, P_HIKEY)))
         {
             char       *itid,
                        *htid;
 
             itid = psprintf("(%u,%u)", state->targetblock, offset);
             htid = psprintf("(%u,%u)",
                             ItemPointerGetBlockNumberNoCheck(&(itup->t_tid)),
                             ItemPointerGetOffsetNumberNoCheck(&(itup->t_tid)));
 
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("high key invariant violated for index \"%s\"",
                             RelationGetRelationName(state->rel)),
                      errdetail_internal("Index tid=%s points to %s tid=%s page lsn=%X/%X.",
                                         itid,
                                         P_ISLEAF(topaque) ? "heap" : "index",
                                         htid,
                                         (uint32) (state->targetlsn >> 32),
                                         (uint32) state->targetlsn)));
         }
 
         /*
          * * Item order check *
          *
          * Check that items are stored on page in logical order, by checking
          * current item is strictly less than next item (if any).
          */
         if (OffsetNumberNext(offset) <= max &&
             !invariant_l_offset(state, skey, OffsetNumberNext(offset)))
         {
             char       *itid,
                        *htid,
                        *nitid,
                        *nhtid;
 
             itid = psprintf("(%u,%u)", state->targetblock, offset);
             htid = psprintf("(%u,%u)",
                             ItemPointerGetBlockNumberNoCheck(&(itup->t_tid)),
                             ItemPointerGetOffsetNumberNoCheck(&(itup->t_tid)));
             nitid = psprintf("(%u,%u)", state->targetblock,
                              OffsetNumberNext(offset));
 
             /* Reuse itup to get pointed-to heap location of second item */
             itemid = PageGetItemIdCareful(state, state->targetblock,
                                           state->target,
                                           OffsetNumberNext(offset));
             itup = (IndexTuple) PageGetItem(state->target, itemid);
             nhtid = psprintf("(%u,%u)",
                              ItemPointerGetBlockNumberNoCheck(&(itup->t_tid)),
                              ItemPointerGetOffsetNumberNoCheck(&(itup->t_tid)));
 
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("item order invariant violated for index \"%s\"",
                             RelationGetRelationName(state->rel)),
                      errdetail_internal("Lower index tid=%s (points to %s tid=%s) "
                                         "higher index tid=%s (points to %s tid=%s) "
                                         "page lsn=%X/%X.",
                                         itid,
                                         P_ISLEAF(topaque) ? "heap" : "index",
                                         htid,
                                         nitid,
                                         P_ISLEAF(topaque) ? "heap" : "index",
                                         nhtid,
                                         (uint32) (state->targetlsn >> 32),
                                         (uint32) state->targetlsn)));
         }
 
         /*
          * * Last item check *
          *
          * Check last item against next/right page's first data item's when
          * last item on page is reached.  This additional check will detect
          * transposed pages iff the supposed right sibling page happens to
          * belong before target in the key space.  (Otherwise, a subsequent
          * heap verification will probably detect the problem.)
          *
          * This check is similar to the item order check that will have
          * already been performed for every other "real" item on target page
          * when last item is checked.  The difference is that the next item
          * (the item that is compared to target's last item) needs to come
          * from the next/sibling page.  There may not be such an item
          * available from sibling for various reasons, though (e.g., target is
          * the rightmost page on level).
          */
         else if (offset == max)
         {
             BTScanInsert rightkey;
 
             /* Get item in next/right page */
             rightkey = bt_right_page_check_scankey(state);
 
             if (rightkey &&
                 !invariant_g_offset(state, rightkey, max))
             {
                 /*
                  * As explained at length in bt_right_page_check_scankey(),
                  * there is a known !readonly race that could account for
                  * apparent violation of invariant, which we must check for
                  * before actually proceeding with raising error.  Our canary
                  * condition is that target page was deleted.
                  */
                 if (!state->readonly)
                 {
                     /* Get fresh copy of target page */
                     state->target = palloc_btree_page(state, state->targetblock);
                     /* Note that we deliberately do not update target LSN */
                     topaque = (BTPageOpaque) PageGetSpecialPointer(state->target);
 
                     /*
                      * All !readonly checks now performed; just return
                      */
                     if (P_IGNORE(topaque))
                         return;
                 }
 
                 ereport(ERROR,
                         (errcode(ERRCODE_INDEX_CORRUPTED),
                          errmsg("cross page item order invariant violated for index \"%s\"",
                                 RelationGetRelationName(state->rel)),
                          errdetail_internal("Last item on page tid=(%u,%u) page lsn=%X/%X.",
                                             state->targetblock, offset,
                                             (uint32) (state->targetlsn >> 32),
                                             (uint32) state->targetlsn)));
             }
         }
 
         /*
          * * Downlink check *
          *
          * Additional check of child items iff this is an internal page and
          * caller holds a ShareLock.  This happens for every downlink (item)
          * in target excluding the negative-infinity downlink (again, this is
          * because it has no useful value to compare).
          */
         if (!P_ISLEAF(topaque) && state->readonly)
         {
             BlockNumber childblock = BTreeInnerTupleGetDownLink(itup);
 
             bt_downlink_check(state, skey, childblock);
         }
     }
 
     /*
      * * Check if page has a downlink in parent *
      *
      * This can only be checked in heapallindexed + readonly case.
      */
     if (state->heapallindexed && state->readonly)
         bt_downlink_missing_check(state);
 }

◆ bt_tuple_present_callback()

static void bt_tuple_present_callback	(	Relation	index,
		HeapTuple	htup,
		Datum *	values,
		bool *	isnull,
		bool	tupleIsAlive,
		void *	checkstate
	)

static

Definition at line 1893 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, HeapTupleData::t_self, and IndexTupleData::t_tid.

Referenced by bt_check_every_level().

 {
     BtreeCheckState *state = (BtreeCheckState *) checkstate;
     IndexTuple  itup,
                 norm;
 
     Assert(state->heapallindexed);
 
     /* Generate a normalized index tuple for fingerprinting */
     itup = index_form_tuple(RelationGetDescr(index), values, isnull);
     itup->t_tid = htup->t_self;
     norm = bt_normalize_tuple(state, itup);
 
     /* Probe Bloom filter -- tuple should be present */
     if (bloom_lacks_element(state->filter, (unsigned char *) norm,
                             IndexTupleSize(norm)))
         ereport(ERROR,
                 (errcode(ERRCODE_DATA_CORRUPTED),
                  errmsg("heap tuple (%u,%u) from table \"%s\" lacks matching index tuple within index \"%s\"",
                         ItemPointerGetBlockNumber(&(itup->t_tid)),
                         ItemPointerGetOffsetNumber(&(itup->t_tid)),
                         RelationGetRelationName(state->heaprel),
                         RelationGetRelationName(state->rel)),
                  !state->readonly
                  ? errhint("Retrying verification using the function bt_index_parent_check() might provide a more specific error.")
                  : 0));
 
     state->heaptuplespresent++;
     pfree(itup);
     /* Cannot leak memory here */
     if (norm != itup)
         pfree(norm);
 }

◆ btree_index_checkable()

static void btree_index_checkable ( Relation rel )

inlinestatic

Definition at line 315 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().

 {
     if (rel->rd_rel->relkind != RELKIND_INDEX ||
         rel->rd_rel->relam != BTREE_AM_OID)
         ereport(ERROR,
                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                  errmsg("only B-Tree indexes are supported as targets for verification"),
                  errdetail("Relation \"%s\" is not a B-Tree index.",
                            RelationGetRelationName(rel))));
 
     if (RELATION_IS_OTHER_TEMP(rel))
         ereport(ERROR,
                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                  errmsg("cannot access temporary tables of other sessions"),
                  errdetail("Index \"%s\" is associated with temporary relation.",
                            RelationGetRelationName(rel))));
 
     if (!rel->rd_index->indisvalid)
         ereport(ERROR,
                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                  errmsg("cannot check index \"%s\"",
                         RelationGetRelationName(rel)),
                  errdetail("Index is not valid.")));
 }

◆ btree_index_mainfork_expected()

static bool btree_index_mainfork_expected ( Relation rel )

inlinestatic

Definition at line 348 of file verify_nbtree.c.

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

Referenced by bt_index_check_internal().

 {
     if (rel->rd_rel->relpersistence != RELPERSISTENCE_UNLOGGED ||
         !RecoveryInProgress())
         return true;
 
     ereport(NOTICE,
             (errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
              errmsg("cannot verify unlogged index \"%s\" during recovery, skipping",
                     RelationGetRelationName(rel))));
 
     return false;
 }

◆ BTreeTupleGetHeapTIDCareful()

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

inlinestatic

Definition at line 2560 of file verify_nbtree.c.

References BTreeTupleGetHeapTID, ereport, errcode(), errmsg(), ERROR, BtreeCheckState::rel, RelationGetRelationName, and BtreeCheckState::targetblock.

Referenced by invariant_l_nontarget_offset(), and invariant_l_offset().

 {
     ItemPointer result = BTreeTupleGetHeapTID(itup);
     BlockNumber targetblock = state->targetblock;
 
     if (result == NULL && nonpivot)
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg("block %u or its right sibling block or child block in index \"%s\" contains non-pivot tuple that lacks a heap TID",
                         targetblock, RelationGetRelationName(state->rel))));
 
     return result;
 }

◆ invariant_g_offset()

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

inlinestatic

Definition at line 2241 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().

 {
     int32       cmp;
 
     Assert(key->pivotsearch);
 
     cmp = _bt_compare(state->rel, key, state->target, lowerbound);
 
     /* pg_upgrade'd indexes may legally have equal sibling tuples */
     if (!key->heapkeyspace)
         return cmp >= 0;
 
     /*
      * No need to consider the possibility that scankey has attributes that we
      * need to force to be interpreted as negative infinity.  _bt_compare() is
      * able to determine that scankey is greater than negative infinity.  The
      * distinction between "==" and "<" isn't interesting here, since
      * corruption is indicated either way.
      */
     return cmp > 0;
 }

◆ invariant_l_nontarget_offset()

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

inlinestatic

Definition at line 2277 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_downlink_check().

 {
     ItemId      itemid;
     int32       cmp;
 
     Assert(key->pivotsearch);
 
     /* Verify line pointer before checking tuple */
     itemid = PageGetItemIdCareful(state, nontargetblock, nontarget,
                                   upperbound);
     cmp = _bt_compare(state->rel, key, nontarget, upperbound);
 
     /* pg_upgrade'd indexes may legally have equal sibling tuples */
     if (!key->heapkeyspace)
         return cmp <= 0;
 
     /* See invariant_l_offset() for an explanation of this extra step */
     if (cmp == 0)
     {
         IndexTuple  child;
         int         uppnkeyatts;
         ItemPointer childheaptid;
         BTPageOpaque copaque;
         bool        nonpivot;
 
         child = (IndexTuple) PageGetItem(nontarget, itemid);
         copaque = (BTPageOpaque) PageGetSpecialPointer(nontarget);
         nonpivot = P_ISLEAF(copaque) && upperbound >= P_FIRSTDATAKEY(copaque);
 
         /* Get number of keys + heap TID for child/non-target item */
         uppnkeyatts = BTreeTupleGetNKeyAtts(child, state->rel);
         childheaptid = BTreeTupleGetHeapTIDCareful(state, child, nonpivot);
 
         /* Heap TID is tiebreaker key attribute */
         if (key->keysz == uppnkeyatts)
             return key->scantid == NULL && childheaptid != NULL;
 
         return key->keysz < uppnkeyatts;
     }
 
     return cmp < 0;
 }

◆ invariant_l_offset()

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

inlinestatic

Definition at line 2155 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().

 {
     ItemId      itemid;
     int32       cmp;
 
     Assert(key->pivotsearch);
 
     /* Verify line pointer before checking tuple */
     itemid = PageGetItemIdCareful(state, state->targetblock, state->target,
                                   upperbound);
     /* pg_upgrade'd indexes may legally have equal sibling tuples */
     if (!key->heapkeyspace)
         return invariant_leq_offset(state, key, upperbound);
 
     cmp = _bt_compare(state->rel, key, state->target, upperbound);
 
     /*
      * _bt_compare() is capable of determining that a scankey with a
      * filled-out attribute is greater than pivot tuples where the comparison
      * is resolved at a truncated attribute (value of attribute in pivot is
      * minus infinity).  However, it is not capable of determining that a
      * scankey is _less than_ a tuple on the basis of a comparison resolved at
      * _scankey_ minus infinity attribute.  Complete an extra step to simulate
      * having minus infinity values for omitted scankey attribute(s).
      */
     if (cmp == 0)
     {
         BTPageOpaque topaque;
         IndexTuple  ritup;
         int         uppnkeyatts;
         ItemPointer rheaptid;
         bool        nonpivot;
 
         ritup = (IndexTuple) PageGetItem(state->target, itemid);
         topaque = (BTPageOpaque) PageGetSpecialPointer(state->target);
         nonpivot = P_ISLEAF(topaque) && upperbound >= P_FIRSTDATAKEY(topaque);
 
         /* Get number of keys + heap TID for item to the right */
         uppnkeyatts = BTreeTupleGetNKeyAtts(ritup, state->rel);
         rheaptid = BTreeTupleGetHeapTIDCareful(state, ritup, nonpivot);
 
         /* Heap TID is tiebreaker key attribute */
         if (key->keysz == uppnkeyatts)
             return key->scantid == NULL && rheaptid != NULL;
 
         return key->keysz < uppnkeyatts;
     }
 
     return cmp < 0;
 }

◆ invariant_leq_offset()

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

inlinestatic

Definition at line 2218 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().

 {
     int32       cmp;
 
     Assert(key->pivotsearch);
 
     cmp = _bt_compare(state->rel, key, state->target, upperbound);
 
     return cmp <= 0;
 }

◆ offset_is_negative_infinity()

static bool offset_is_negative_infinity	(	BTPageOpaque	opaque,
		OffsetNumber	offset
	)

inlinestatic

Definition at line 2120 of file verify_nbtree.c.

References P_FIRSTDATAKEY, and P_ISLEAF.

Referenced by bt_downlink_check(), and bt_target_page_check().

 {
     /*
      * For internal pages only, the first item after high key, if any, is
      * negative infinity item.  Internal pages always have a negative infinity
      * item, whereas leaf pages never have one.  This implies that negative
      * infinity item is either first or second line item, or there is none
      * within page.
      *
      * Negative infinity items are a special case among pivot tuples.  They
      * always have zero attributes, while all other pivot tuples always have
      * nkeyatts attributes.
      *
      * Right-most pages don't have a high key, but could be said to
      * conceptually have a "positive infinity" high key.  Thus, there is a
      * symmetry between down link items in parent pages, and high keys in
      * children.  Together, they represent the part of the key space that
      * belongs to each page in the index.  For example, all children of the
      * root page will have negative infinity as a lower bound from root
      * negative infinity downlink, and positive infinity as an upper bound
      * (implicitly, from "imaginary" positive infinity high key in root).
      */
     return !P_ISLEAF(opaque) && offset == P_FIRSTDATAKEY(opaque);
 }

◆ PageGetItemIdCareful()

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

static

Definition at line 2515 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_downlink_missing_check(), bt_right_page_check_scankey(), bt_target_page_check(), invariant_l_nontarget_offset(), and invariant_l_offset().

 {
     ItemId      itemid = PageGetItemId(page, offset);
 
     if (ItemIdGetOffset(itemid) + ItemIdGetLength(itemid) >
         BLCKSZ - sizeof(BTPageOpaqueData))
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg("line pointer points past end of tuple space in index \"%s\"",
                         RelationGetRelationName(state->rel)),
                  errdetail_internal("Index tid=(%u,%u) lp_off=%u, lp_len=%u lp_flags=%u.",
                                     block, offset, ItemIdGetOffset(itemid),
                                     ItemIdGetLength(itemid),
                                     ItemIdGetFlags(itemid))));
 
     /*
      * Verify that line pointer isn't LP_REDIRECT or LP_UNUSED, since nbtree
      * never uses either.  Verify that line pointer has storage, too, since
      * even LP_DEAD items should within nbtree.
      */
     if (ItemIdIsRedirected(itemid) || !ItemIdIsUsed(itemid) ||
         ItemIdGetLength(itemid) == 0)
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg("invalid line pointer storage in index \"%s\"",
                         RelationGetRelationName(state->rel)),
                  errdetail_internal("Index tid=(%u,%u) lp_off=%u, lp_len=%u lp_flags=%u.",
                                     block, offset, ItemIdGetOffset(itemid),
                                     ItemIdGetLength(itemid),
                                     ItemIdGetFlags(itemid))));
 
     return itemid;
 }

◆ palloc_btree_page()

static Page palloc_btree_page	(	BtreeCheckState *	state,
		BlockNumber	blocknum
	)

static

Definition at line 2335 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_downlink_check(), bt_downlink_missing_check(), bt_right_page_check_scankey(), and bt_target_page_check().

 {
     Buffer      buffer;
     Page        page;
     BTPageOpaque opaque;
     OffsetNumber maxoffset;
 
     page = palloc(BLCKSZ);
 
     /*
      * We copy the page into local storage to avoid holding pin on the buffer
      * longer than we must.
      */
     buffer = ReadBufferExtended(state->rel, MAIN_FORKNUM, blocknum, RBM_NORMAL,
                                 state->checkstrategy);
     LockBuffer(buffer, BT_READ);
 
     /*
      * Perform the same basic sanity checking that nbtree itself performs for
      * every page:
      */
     _bt_checkpage(state->rel, buffer);
 
     /* Only use copy of page in palloc()'d memory */
     memcpy(page, BufferGetPage(buffer), BLCKSZ);
     UnlockReleaseBuffer(buffer);
 
     opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 
     if (P_ISMETA(opaque) && blocknum != BTREE_METAPAGE)
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg("invalid meta page found at block %u in index \"%s\"",
                         blocknum, RelationGetRelationName(state->rel))));
 
     /* Check page from block that ought to be meta page */
     if (blocknum == BTREE_METAPAGE)
     {
         BTMetaPageData *metad = BTPageGetMeta(page);
 
         if (!P_ISMETA(opaque) ||
             metad->btm_magic != BTREE_MAGIC)
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("index \"%s\" meta page is corrupt",
                             RelationGetRelationName(state->rel))));
 
         if (metad->btm_version < BTREE_MIN_VERSION ||
             metad->btm_version > BTREE_VERSION)
             ereport(ERROR,
                     (errcode(ERRCODE_INDEX_CORRUPTED),
                      errmsg("version mismatch in index \"%s\": file version %d, "
                             "current version %d, minimum supported version %d",
                             RelationGetRelationName(state->rel),
                             metad->btm_version, BTREE_VERSION,
                             BTREE_MIN_VERSION)));
 
         /* Finished with metapage checks */
         return page;
     }
 
     /*
      * Deleted pages have no sane "level" field, so can only check non-deleted
      * page level
      */
     if (P_ISLEAF(opaque) && !P_ISDELETED(opaque) && opaque->btpo.level != 0)
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg("invalid leaf page level %u for block %u in index \"%s\"",
                         opaque->btpo.level, blocknum, RelationGetRelationName(state->rel))));
 
     if (!P_ISLEAF(opaque) && !P_ISDELETED(opaque) &&
         opaque->btpo.level == 0)
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg("invalid internal page level 0 for block %u in index \"%s\"",
                         blocknum, RelationGetRelationName(state->rel))));
 
     /*
      * Sanity checks for number of items on page.
      *
      * As noted at the beginning of _bt_binsrch(), an internal page must have
      * children, since there must always be a negative infinity downlink
      * (there may also be a highkey).  In the case of non-rightmost leaf
      * pages, there must be at least a highkey.
      *
      * This is correct when pages are half-dead, since internal pages are
      * never half-dead, and leaf pages must have a high key when half-dead
      * (the rightmost page can never be deleted).  It's also correct with
      * fully deleted pages: _bt_unlink_halfdead_page() doesn't change anything
      * about the target page other than setting the page as fully dead, and
      * setting its xact field.  In particular, it doesn't change the sibling
      * links in the deletion target itself, since they're required when index
      * scans land on the deletion target, and then need to move right (or need
      * to move left, in the case of backward index scans).
      */
     maxoffset = PageGetMaxOffsetNumber(page);
     if (maxoffset > MaxIndexTuplesPerPage)
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg("Number of items on block %u of index \"%s\" exceeds MaxIndexTuplesPerPage (%u)",
                         blocknum, RelationGetRelationName(state->rel),
                         MaxIndexTuplesPerPage)));
 
     if (!P_ISLEAF(opaque) && maxoffset < P_FIRSTDATAKEY(opaque))
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg("internal block %u in index \"%s\" lacks high key and/or at least one downlink",
                         blocknum, RelationGetRelationName(state->rel))));
 
     if (P_ISLEAF(opaque) && !P_RIGHTMOST(opaque) && maxoffset < P_HIKEY)
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg("non-rightmost leaf block %u in index \"%s\" lacks high key item",
                         blocknum, RelationGetRelationName(state->rel))));
 
     /*
      * In general, internal pages are never marked half-dead, except on
      * versions of Postgres prior to 9.4, where it can be valid transient
      * state.  This state is nonetheless treated as corruption by VACUUM on
      * from version 9.4 on, so do the same here.  See _bt_pagedel() for full
      * details.
      *
      * Internal pages should never have garbage items, either.
      */
     if (!P_ISLEAF(opaque) && P_ISHALFDEAD(opaque))
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg("internal page block %u in index \"%s\" is half-dead",
                         blocknum, RelationGetRelationName(state->rel)),
                  errhint("This can be caused by an interrupted VACUUM in version 9.3 or older, before upgrade. Please REINDEX it.")));
 
     if (!P_ISLEAF(opaque) && P_HAS_GARBAGE(opaque))
         ereport(ERROR,
                 (errcode(ERRCODE_INDEX_CORRUPTED),
                  errmsg("internal page block %u in index \"%s\" has garbage items",
                         blocknum, RelationGetRelationName(state->rel))));
 
     return page;
 }

◆ 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.

Data Structures

Macros

Typedefs

Functions

Variables

Macro Definition Documentation

◆ BTreeTupleGetNKeyAtts

◆ InvalidBtreeLevel

Typedef Documentation

◆ BtreeCheckState

◆ BtreeLevel

Function Documentation

◆ bt_check_every_level()

◆ bt_check_level_from_leftmost()

◆ bt_downlink_check()

◆ bt_downlink_missing_check()

◆ bt_index_check()

◆ bt_index_check_internal()

◆ bt_index_parent_check()

◆ bt_mkscankey_pivotsearch()

◆ bt_normalize_tuple()

◆ bt_right_page_check_scankey()

◆ bt_rootdescend()

◆ bt_target_page_check()

◆ bt_tuple_present_callback()

◆ btree_index_checkable()

◆ btree_index_mainfork_expected()

◆ BTreeTupleGetHeapTIDCareful()

◆ invariant_g_offset()

◆ invariant_l_nontarget_offset()

◆ invariant_l_offset()

◆ invariant_leq_offset()

◆ offset_is_negative_infinity()

◆ PageGetItemIdCareful()

◆ palloc_btree_page()

◆ PG_FUNCTION_INFO_V1() [1/2]

◆ PG_FUNCTION_INFO_V1() [2/2]

Variable Documentation

◆ PG_MODULE_MAGIC