PostgreSQL Source Code  git master
rewriteheap.h File Reference
#include "access/htup.h"
#include "storage/itemptr.h"
#include "storage/relfilenode.h"
#include "utils/relcache.h"
Include dependency graph for rewriteheap.h:
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Data Structures

struct  LogicalRewriteMappingData
 

Macros

#define LOGICAL_REWRITE_FORMAT   "map-%x-%x-%X_%X-%x-%x"
 

Typedefs

typedef struct RewriteStateDataRewriteState
 
typedef struct LogicalRewriteMappingData LogicalRewriteMappingData
 

Functions

RewriteState begin_heap_rewrite (Relation OldHeap, Relation NewHeap, TransactionId OldestXmin, TransactionId FreezeXid, MultiXactId MultiXactCutoff, bool use_wal)
 
void end_heap_rewrite (RewriteState state)
 
void rewrite_heap_tuple (RewriteState state, HeapTuple oldTuple, HeapTuple newTuple)
 
bool rewrite_heap_dead_tuple (RewriteState state, HeapTuple oldTuple)
 
void CheckPointLogicalRewriteHeap (void)
 

Macro Definition Documentation

◆ LOGICAL_REWRITE_FORMAT

#define LOGICAL_REWRITE_FORMAT   "map-%x-%x-%X_%X-%x-%x"

Typedef Documentation

◆ LogicalRewriteMappingData

◆ RewriteState

typedef struct RewriteStateData* RewriteState

Definition at line 22 of file rewriteheap.h.

Function Documentation

◆ begin_heap_rewrite()

RewriteState begin_heap_rewrite ( Relation  OldHeap,
Relation  NewHeap,
TransactionId  OldestXmin,
TransactionId  FreezeXid,
MultiXactId  MultiXactCutoff,
bool  use_wal 
)

Definition at line 247 of file rewriteheap.c.

References ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate, CurrentMemoryContext, HASHCTL::entrysize, HASH_BLOBS, HASH_CONTEXT, hash_create(), HASH_ELEM, HASHCTL::hcxt, HASHCTL::keysize, logical_begin_heap_rewrite(), MemoryContextSwitchTo(), palloc(), palloc0(), RelationGetNumberOfBlocks, RewriteStateData::rs_blockno, RewriteStateData::rs_buffer, RewriteStateData::rs_buffer_valid, RewriteStateData::rs_cutoff_multi, RewriteStateData::rs_cxt, RewriteStateData::rs_freeze_xid, RewriteStateData::rs_new_rel, RewriteStateData::rs_old_new_tid_map, RewriteStateData::rs_old_rel, RewriteStateData::rs_oldest_xmin, RewriteStateData::rs_unresolved_tups, and RewriteStateData::rs_use_wal.

Referenced by heapam_relation_copy_for_cluster().

250 {
252  MemoryContext rw_cxt;
253  MemoryContext old_cxt;
254  HASHCTL hash_ctl;
255 
256  /*
257  * To ease cleanup, make a separate context that will contain the
258  * RewriteState struct itself plus all subsidiary data.
259  */
261  "Table rewrite",
263  old_cxt = MemoryContextSwitchTo(rw_cxt);
264 
265  /* Create and fill in the state struct */
266  state = palloc0(sizeof(RewriteStateData));
267 
268  state->rs_old_rel = old_heap;
269  state->rs_new_rel = new_heap;
270  state->rs_buffer = (Page) palloc(BLCKSZ);
271  /* new_heap needn't be empty, just locked */
272  state->rs_blockno = RelationGetNumberOfBlocks(new_heap);
273  state->rs_buffer_valid = false;
274  state->rs_use_wal = use_wal;
275  state->rs_oldest_xmin = oldest_xmin;
276  state->rs_freeze_xid = freeze_xid;
277  state->rs_cutoff_multi = cutoff_multi;
278  state->rs_cxt = rw_cxt;
279 
280  /* Initialize hash tables used to track update chains */
281  memset(&hash_ctl, 0, sizeof(hash_ctl));
282  hash_ctl.keysize = sizeof(TidHashKey);
283  hash_ctl.entrysize = sizeof(UnresolvedTupData);
284  hash_ctl.hcxt = state->rs_cxt;
285 
286  state->rs_unresolved_tups =
287  hash_create("Rewrite / Unresolved ctids",
288  128, /* arbitrary initial size */
289  &hash_ctl,
291 
292  hash_ctl.entrysize = sizeof(OldToNewMappingData);
293 
294  state->rs_old_new_tid_map =
295  hash_create("Rewrite / Old to new tid map",
296  128, /* arbitrary initial size */
297  &hash_ctl,
299 
300  MemoryContextSwitchTo(old_cxt);
301 
303 
304  return state;
305 }
#define AllocSetContextCreate
Definition: memutils.h:170
#define HASH_CONTEXT
Definition: hsearch.h:93
#define HASH_ELEM
Definition: hsearch.h:87
MemoryContext hcxt
Definition: hsearch.h:78
TransactionId rs_freeze_xid
Definition: rewriteheap.c:151
MultiXactId rs_cutoff_multi
Definition: rewriteheap.c:155
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:109
Size entrysize
Definition: hsearch.h:73
Relation rs_new_rel
Definition: rewriteheap.c:143
HTAB * rs_unresolved_tups
Definition: rewriteheap.c:160
#define ALLOCSET_DEFAULT_SIZES
Definition: memutils.h:192
MemoryContext CurrentMemoryContext
Definition: mcxt.c:38
TransactionId rs_oldest_xmin
Definition: rewriteheap.c:149
#define HASH_BLOBS
Definition: hsearch.h:88
MemoryContext rs_cxt
Definition: rewriteheap.c:157
void * palloc0(Size size)
Definition: mcxt.c:980
HTAB * hash_create(const char *tabname, long nelem, HASHCTL *info, int flags)
Definition: dynahash.c:316
Size keysize
Definition: hsearch.h:72
#define RelationGetNumberOfBlocks(reln)
Definition: bufmgr.h:198
static void logical_begin_heap_rewrite(RewriteState state)
Definition: rewriteheap.c:814
HTAB * rs_old_new_tid_map
Definition: rewriteheap.c:161
Definition: regguts.h:298
void * palloc(Size size)
Definition: mcxt.c:949
Relation rs_old_rel
Definition: rewriteheap.c:142
BlockNumber rs_blockno
Definition: rewriteheap.c:145
Pointer Page
Definition: bufpage.h:78

◆ CheckPointLogicalRewriteHeap()

void CheckPointLogicalRewriteHeap ( void  )

Definition at line 1222 of file rewriteheap.c.

References AllocateDir(), CloseTransientFile(), dirent::d_name, data_sync_elevel(), DEBUG1, elog, ereport, errcode_for_file_access(), errmsg(), ERROR, fd(), FreeDir(), GetRedoRecPtr(), InvalidXLogRecPtr, LOGICAL_REWRITE_FORMAT, lstat, MAXPGPATH, OpenTransientFile(), PG_BINARY, pg_fsync(), pgstat_report_wait_end(), pgstat_report_wait_start(), ReadDir(), ReplicationSlotsComputeLogicalRestartLSN(), S_ISREG, snprintf, stat, and WAIT_EVENT_LOGICAL_REWRITE_CHECKPOINT_SYNC.

Referenced by CheckPointGuts().

1223 {
1224  XLogRecPtr cutoff;
1225  XLogRecPtr redo;
1226  DIR *mappings_dir;
1227  struct dirent *mapping_de;
1228  char path[MAXPGPATH + 20];
1229 
1230  /*
1231  * We start of with a minimum of the last redo pointer. No new decoding
1232  * slot will start before that, so that's a safe upper bound for removal.
1233  */
1234  redo = GetRedoRecPtr();
1235 
1236  /* now check for the restart ptrs from existing slots */
1238 
1239  /* don't start earlier than the restart lsn */
1240  if (cutoff != InvalidXLogRecPtr && redo < cutoff)
1241  cutoff = redo;
1242 
1243  mappings_dir = AllocateDir("pg_logical/mappings");
1244  while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
1245  {
1246  struct stat statbuf;
1247  Oid dboid;
1248  Oid relid;
1249  XLogRecPtr lsn;
1250  TransactionId rewrite_xid;
1251  TransactionId create_xid;
1252  uint32 hi,
1253  lo;
1254 
1255  if (strcmp(mapping_de->d_name, ".") == 0 ||
1256  strcmp(mapping_de->d_name, "..") == 0)
1257  continue;
1258 
1259  snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
1260  if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
1261  continue;
1262 
1263  /* Skip over files that cannot be ours. */
1264  if (strncmp(mapping_de->d_name, "map-", 4) != 0)
1265  continue;
1266 
1267  if (sscanf(mapping_de->d_name, LOGICAL_REWRITE_FORMAT,
1268  &dboid, &relid, &hi, &lo, &rewrite_xid, &create_xid) != 6)
1269  elog(ERROR, "could not parse filename \"%s\"", mapping_de->d_name);
1270 
1271  lsn = ((uint64) hi) << 32 | lo;
1272 
1273  if (lsn < cutoff || cutoff == InvalidXLogRecPtr)
1274  {
1275  elog(DEBUG1, "removing logical rewrite file \"%s\"", path);
1276  if (unlink(path) < 0)
1277  ereport(ERROR,
1279  errmsg("could not remove file \"%s\": %m", path)));
1280  }
1281  else
1282  {
1283  /* on some operating systems fsyncing a file requires O_RDWR */
1284  int fd = OpenTransientFile(path, O_RDWR | PG_BINARY);
1285 
1286  /*
1287  * The file cannot vanish due to concurrency since this function
1288  * is the only one removing logical mappings and it's run while
1289  * CheckpointLock is held exclusively.
1290  */
1291  if (fd < 0)
1292  ereport(ERROR,
1294  errmsg("could not open file \"%s\": %m", path)));
1295 
1296  /*
1297  * We could try to avoid fsyncing files that either haven't
1298  * changed or have only been created since the checkpoint's start,
1299  * but it's currently not deemed worth the effort.
1300  */
1302  if (pg_fsync(fd) != 0)
1305  errmsg("could not fsync file \"%s\": %m", path)));
1307 
1308  if (CloseTransientFile(fd) != 0)
1309  ereport(ERROR,
1311  errmsg("could not close file \"%s\": %m", path)));
1312  }
1313  }
1314  FreeDir(mappings_dir);
1315 }
#define InvalidXLogRecPtr
Definition: xlogdefs.h:28
#define DEBUG1
Definition: elog.h:25
uint32 TransactionId
Definition: c.h:507
unsigned int Oid
Definition: postgres_ext.h:31
Definition: dirent.h:9
static int fd(const char *x, int i)
Definition: preproc-init.c:105
#define PG_BINARY
Definition: c.h:1191
Definition: dirent.c:25
#define ERROR
Definition: elog.h:43
int OpenTransientFile(const char *fileName, int fileFlags)
Definition: fd.c:2255
#define MAXPGPATH
int errcode_for_file_access(void)
Definition: elog.c:593
XLogRecPtr ReplicationSlotsComputeLogicalRestartLSN(void)
Definition: slot.c:791
unsigned int uint32
Definition: c.h:358
DIR * AllocateDir(const char *dirname)
Definition: fd.c:2466
static void pgstat_report_wait_end(void)
Definition: pgstat.h:1342
#define ereport(elevel, rest)
Definition: elog.h:141
#define S_ISREG(m)
Definition: win32_port.h:299
int CloseTransientFile(int fd)
Definition: fd.c:2432
#define stat(a, b)
Definition: win32_port.h:255
int data_sync_elevel(int elevel)
Definition: fd.c:3482
uint64 XLogRecPtr
Definition: xlogdefs.h:21
struct dirent * ReadDir(DIR *dir, const char *dirname)
Definition: fd.c:2532
static void pgstat_report_wait_start(uint32 wait_event_info)
Definition: pgstat.h:1318
XLogRecPtr GetRedoRecPtr(void)
Definition: xlog.c:8186
#define LOGICAL_REWRITE_FORMAT
Definition: rewriteheap.h:54
#define lstat(path, sb)
Definition: win32_port.h:244
int errmsg(const char *fmt,...)
Definition: elog.c:784
#define elog(elevel,...)
Definition: elog.h:226
int pg_fsync(int fd)
Definition: fd.c:331
char d_name[MAX_PATH]
Definition: dirent.h:14
#define snprintf
Definition: port.h:192
int FreeDir(DIR *dir)
Definition: fd.c:2584

◆ end_heap_rewrite()

void end_heap_rewrite ( RewriteState  state)

Definition at line 313 of file rewriteheap.c.

References hash_seq_init(), hash_seq_search(), heap_sync(), ItemPointerSetInvalid, log_newpage(), logical_end_heap_rewrite(), MAIN_FORKNUM, MemoryContextDelete(), PageSetChecksumInplace(), raw_heap_insert(), RelationData::rd_node, RelationData::rd_smgr, RelationNeedsWAL, RelationOpenSmgr, RewriteStateData::rs_blockno, RewriteStateData::rs_buffer, RewriteStateData::rs_buffer_valid, RewriteStateData::rs_cxt, RewriteStateData::rs_new_rel, RewriteStateData::rs_unresolved_tups, RewriteStateData::rs_use_wal, smgrextend(), HeapTupleHeaderData::t_ctid, HeapTupleData::t_data, and UnresolvedTupData::tuple.

Referenced by heapam_relation_copy_for_cluster().

314 {
315  HASH_SEQ_STATUS seq_status;
316  UnresolvedTup unresolved;
317 
318  /*
319  * Write any remaining tuples in the UnresolvedTups table. If we have any
320  * left, they should in fact be dead, but let's err on the safe side.
321  */
322  hash_seq_init(&seq_status, state->rs_unresolved_tups);
323 
324  while ((unresolved = hash_seq_search(&seq_status)) != NULL)
325  {
326  ItemPointerSetInvalid(&unresolved->tuple->t_data->t_ctid);
327  raw_heap_insert(state, unresolved->tuple);
328  }
329 
330  /* Write the last page, if any */
331  if (state->rs_buffer_valid)
332  {
333  if (state->rs_use_wal)
334  log_newpage(&state->rs_new_rel->rd_node,
335  MAIN_FORKNUM,
336  state->rs_blockno,
337  state->rs_buffer,
338  true);
340 
342 
344  (char *) state->rs_buffer, true);
345  }
346 
347  /*
348  * If the rel is WAL-logged, must fsync before commit. We use heap_sync
349  * to ensure that the toast table gets fsync'd too.
350  *
351  * It's obvious that we must do this when not WAL-logging. It's less
352  * obvious that we have to do it even if we did WAL-log the pages. The
353  * reason is the same as in storage.c's RelationCopyStorage(): we're
354  * writing data that's not in shared buffers, and so a CHECKPOINT
355  * occurring during the rewriteheap operation won't have fsync'd data we
356  * wrote before the checkpoint.
357  */
358  if (RelationNeedsWAL(state->rs_new_rel))
359  heap_sync(state->rs_new_rel);
360 
362 
363  /* Deleting the context frees everything */
364  MemoryContextDelete(state->rs_cxt);
365 }
void MemoryContextDelete(MemoryContext context)
Definition: mcxt.c:211
static void logical_end_heap_rewrite(RewriteState state)
Definition: rewriteheap.c:961
struct SMgrRelationData * rd_smgr
Definition: rel.h:56
Relation rs_new_rel
Definition: rewriteheap.c:143
void heap_sync(Relation rel)
Definition: heapam.c:8938
HeapTupleHeader t_data
Definition: htup.h:68
#define RelationOpenSmgr(relation)
Definition: rel.h:476
ItemPointerData t_ctid
Definition: htup_details.h:160
HTAB * rs_unresolved_tups
Definition: rewriteheap.c:160
MemoryContext rs_cxt
Definition: rewriteheap.c:157
RelFileNode rd_node
Definition: rel.h:54
void PageSetChecksumInplace(Page page, BlockNumber blkno)
Definition: bufpage.c:1198
void * hash_seq_search(HASH_SEQ_STATUS *status)
Definition: dynahash.c:1389
#define RelationNeedsWAL(relation)
Definition: rel.h:521
void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp)
Definition: dynahash.c:1379
void smgrextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum, char *buffer, bool skipFsync)
Definition: smgr.c:483
#define ItemPointerSetInvalid(pointer)
Definition: itemptr.h:172
XLogRecPtr log_newpage(RelFileNode *rnode, ForkNumber forkNum, BlockNumber blkno, Page page, bool page_std)
Definition: xloginsert.c:972
static void raw_heap_insert(RewriteState state, HeapTuple tup)
Definition: rewriteheap.c:631
BlockNumber rs_blockno
Definition: rewriteheap.c:145

◆ rewrite_heap_dead_tuple()

bool rewrite_heap_dead_tuple ( RewriteState  state,
HeapTuple  oldTuple 
)

Definition at line 581 of file rewriteheap.c.

References Assert, HASH_FIND, HASH_REMOVE, hash_search(), heap_freetuple(), HeapTupleHeaderGetXmin, RewriteStateData::rs_unresolved_tups, HeapTupleData::t_data, HeapTupleData::t_self, TidHashKey::tid, UnresolvedTupData::tuple, and TidHashKey::xmin.

Referenced by heapam_relation_copy_for_cluster().

582 {
583  /*
584  * If we have already seen an earlier tuple in the update chain that
585  * points to this tuple, let's forget about that earlier tuple. It's in
586  * fact dead as well, our simple xmax < OldestXmin test in
587  * HeapTupleSatisfiesVacuum just wasn't enough to detect it. It happens
588  * when xmin of a tuple is greater than xmax, which sounds
589  * counter-intuitive but is perfectly valid.
590  *
591  * We don't bother to try to detect the situation the other way round,
592  * when we encounter the dead tuple first and then the recently dead one
593  * that points to it. If that happens, we'll have some unmatched entries
594  * in the UnresolvedTups hash table at the end. That can happen anyway,
595  * because a vacuum might have removed the dead tuple in the chain before
596  * us.
597  */
598  UnresolvedTup unresolved;
599  TidHashKey hashkey;
600  bool found;
601 
602  memset(&hashkey, 0, sizeof(hashkey));
603  hashkey.xmin = HeapTupleHeaderGetXmin(old_tuple->t_data);
604  hashkey.tid = old_tuple->t_self;
605 
606  unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
607  HASH_FIND, NULL);
608 
609  if (unresolved != NULL)
610  {
611  /* Need to free the contained tuple as well as the hashtable entry */
612  heap_freetuple(unresolved->tuple);
613  hash_search(state->rs_unresolved_tups, &hashkey,
614  HASH_REMOVE, &found);
615  Assert(found);
616  return true;
617  }
618 
619  return false;
620 }
void * hash_search(HTAB *hashp, const void *keyPtr, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:906
void heap_freetuple(HeapTuple htup)
Definition: heaptuple.c:1338
HTAB * rs_unresolved_tups
Definition: rewriteheap.c:160
ItemPointerData tid
Definition: rewriteheap.c:175
#define Assert(condition)
Definition: c.h:732
#define HeapTupleHeaderGetXmin(tup)
Definition: htup_details.h:313
TransactionId xmin
Definition: rewriteheap.c:174

◆ rewrite_heap_tuple()

void rewrite_heap_tuple ( RewriteState  state,
HeapTuple  oldTuple,
HeapTuple  newTuple 
)

Definition at line 379 of file rewriteheap.c.

References Assert, HASH_ENTER, HASH_FIND, HASH_REMOVE, hash_search(), HEAP2_XACT_MASK, heap_copytuple(), heap_freetuple(), heap_freeze_tuple(), HEAP_UPDATED, HEAP_XACT_MASK, HEAP_XMAX_INVALID, HeapTupleHeaderGetUpdateXid, HeapTupleHeaderGetXmin, HeapTupleHeaderIndicatesMovedPartitions, HeapTupleHeaderIsOnlyLocked(), ItemPointerEquals(), ItemPointerSetInvalid, logical_rewrite_heap_tuple(), MemoryContextSwitchTo(), OldToNewMappingData::new_tid, UnresolvedTupData::old_tid, raw_heap_insert(), RelationData::rd_rel, RewriteStateData::rs_cutoff_multi, RewriteStateData::rs_cxt, RewriteStateData::rs_freeze_xid, RewriteStateData::rs_old_new_tid_map, RewriteStateData::rs_old_rel, RewriteStateData::rs_oldest_xmin, RewriteStateData::rs_unresolved_tups, HeapTupleHeaderData::t_choice, HeapTupleHeaderData::t_ctid, HeapTupleData::t_data, HeapTupleHeaderData::t_heap, HeapTupleHeaderData::t_infomask, HeapTupleHeaderData::t_infomask2, HeapTupleData::t_self, TidHashKey::tid, TransactionIdPrecedes(), UnresolvedTupData::tuple, and TidHashKey::xmin.

Referenced by reform_and_rewrite_tuple().

381 {
382  MemoryContext old_cxt;
383  ItemPointerData old_tid;
384  TidHashKey hashkey;
385  bool found;
386  bool free_new;
387 
388  old_cxt = MemoryContextSwitchTo(state->rs_cxt);
389 
390  /*
391  * Copy the original tuple's visibility information into new_tuple.
392  *
393  * XXX we might later need to copy some t_infomask2 bits, too? Right now,
394  * we intentionally clear the HOT status bits.
395  */
396  memcpy(&new_tuple->t_data->t_choice.t_heap,
397  &old_tuple->t_data->t_choice.t_heap,
398  sizeof(HeapTupleFields));
399 
400  new_tuple->t_data->t_infomask &= ~HEAP_XACT_MASK;
401  new_tuple->t_data->t_infomask2 &= ~HEAP2_XACT_MASK;
402  new_tuple->t_data->t_infomask |=
403  old_tuple->t_data->t_infomask & HEAP_XACT_MASK;
404 
405  /*
406  * While we have our hands on the tuple, we may as well freeze any
407  * eligible xmin or xmax, so that future VACUUM effort can be saved.
408  */
409  heap_freeze_tuple(new_tuple->t_data,
410  state->rs_old_rel->rd_rel->relfrozenxid,
411  state->rs_old_rel->rd_rel->relminmxid,
412  state->rs_freeze_xid,
413  state->rs_cutoff_multi);
414 
415  /*
416  * Invalid ctid means that ctid should point to the tuple itself. We'll
417  * override it later if the tuple is part of an update chain.
418  */
419  ItemPointerSetInvalid(&new_tuple->t_data->t_ctid);
420 
421  /*
422  * If the tuple has been updated, check the old-to-new mapping hash table.
423  */
424  if (!((old_tuple->t_data->t_infomask & HEAP_XMAX_INVALID) ||
425  HeapTupleHeaderIsOnlyLocked(old_tuple->t_data)) &&
426  !HeapTupleHeaderIndicatesMovedPartitions(old_tuple->t_data) &&
427  !(ItemPointerEquals(&(old_tuple->t_self),
428  &(old_tuple->t_data->t_ctid))))
429  {
430  OldToNewMapping mapping;
431 
432  memset(&hashkey, 0, sizeof(hashkey));
433  hashkey.xmin = HeapTupleHeaderGetUpdateXid(old_tuple->t_data);
434  hashkey.tid = old_tuple->t_data->t_ctid;
435 
436  mapping = (OldToNewMapping)
437  hash_search(state->rs_old_new_tid_map, &hashkey,
438  HASH_FIND, NULL);
439 
440  if (mapping != NULL)
441  {
442  /*
443  * We've already copied the tuple that t_ctid points to, so we can
444  * set the ctid of this tuple to point to the new location, and
445  * insert it right away.
446  */
447  new_tuple->t_data->t_ctid = mapping->new_tid;
448 
449  /* We don't need the mapping entry anymore */
450  hash_search(state->rs_old_new_tid_map, &hashkey,
451  HASH_REMOVE, &found);
452  Assert(found);
453  }
454  else
455  {
456  /*
457  * We haven't seen the tuple t_ctid points to yet. Stash this
458  * tuple into unresolved_tups to be written later.
459  */
460  UnresolvedTup unresolved;
461 
462  unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
463  HASH_ENTER, &found);
464  Assert(!found);
465 
466  unresolved->old_tid = old_tuple->t_self;
467  unresolved->tuple = heap_copytuple(new_tuple);
468 
469  /*
470  * We can't do anything more now, since we don't know where the
471  * tuple will be written.
472  */
473  MemoryContextSwitchTo(old_cxt);
474  return;
475  }
476  }
477 
478  /*
479  * Now we will write the tuple, and then check to see if it is the B tuple
480  * in any new or known pair. When we resolve a known pair, we will be
481  * able to write that pair's A tuple, and then we have to check if it
482  * resolves some other pair. Hence, we need a loop here.
483  */
484  old_tid = old_tuple->t_self;
485  free_new = false;
486 
487  for (;;)
488  {
489  ItemPointerData new_tid;
490 
491  /* Insert the tuple and find out where it's put in new_heap */
492  raw_heap_insert(state, new_tuple);
493  new_tid = new_tuple->t_self;
494 
495  logical_rewrite_heap_tuple(state, old_tid, new_tuple);
496 
497  /*
498  * If the tuple is the updated version of a row, and the prior version
499  * wouldn't be DEAD yet, then we need to either resolve the prior
500  * version (if it's waiting in rs_unresolved_tups), or make an entry
501  * in rs_old_new_tid_map (so we can resolve it when we do see it). The
502  * previous tuple's xmax would equal this one's xmin, so it's
503  * RECENTLY_DEAD if and only if the xmin is not before OldestXmin.
504  */
505  if ((new_tuple->t_data->t_infomask & HEAP_UPDATED) &&
506  !TransactionIdPrecedes(HeapTupleHeaderGetXmin(new_tuple->t_data),
507  state->rs_oldest_xmin))
508  {
509  /*
510  * Okay, this is B in an update pair. See if we've seen A.
511  */
512  UnresolvedTup unresolved;
513 
514  memset(&hashkey, 0, sizeof(hashkey));
515  hashkey.xmin = HeapTupleHeaderGetXmin(new_tuple->t_data);
516  hashkey.tid = old_tid;
517 
518  unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
519  HASH_FIND, NULL);
520 
521  if (unresolved != NULL)
522  {
523  /*
524  * We have seen and memorized the previous tuple already. Now
525  * that we know where we inserted the tuple its t_ctid points
526  * to, fix its t_ctid and insert it to the new heap.
527  */
528  if (free_new)
529  heap_freetuple(new_tuple);
530  new_tuple = unresolved->tuple;
531  free_new = true;
532  old_tid = unresolved->old_tid;
533  new_tuple->t_data->t_ctid = new_tid;
534 
535  /*
536  * We don't need the hash entry anymore, but don't free its
537  * tuple just yet.
538  */
539  hash_search(state->rs_unresolved_tups, &hashkey,
540  HASH_REMOVE, &found);
541  Assert(found);
542 
543  /* loop back to insert the previous tuple in the chain */
544  continue;
545  }
546  else
547  {
548  /*
549  * Remember the new tid of this tuple. We'll use it to set the
550  * ctid when we find the previous tuple in the chain.
551  */
552  OldToNewMapping mapping;
553 
554  mapping = hash_search(state->rs_old_new_tid_map, &hashkey,
555  HASH_ENTER, &found);
556  Assert(!found);
557 
558  mapping->new_tid = new_tid;
559  }
560  }
561 
562  /* Done with this (chain of) tuples, for now */
563  if (free_new)
564  heap_freetuple(new_tuple);
565  break;
566  }
567 
568  MemoryContextSwitchTo(old_cxt);
569 }
#define HeapTupleHeaderGetUpdateXid(tup)
Definition: htup_details.h:365
HeapTuple heap_copytuple(HeapTuple tuple)
Definition: heaptuple.c:680
static void logical_rewrite_heap_tuple(RewriteState state, ItemPointerData old_tid, HeapTuple new_tuple)
Definition: rewriteheap.c:1058
TransactionId rs_freeze_xid
Definition: rewriteheap.c:151
bool HeapTupleHeaderIsOnlyLocked(HeapTupleHeader tuple)
MultiXactId rs_cutoff_multi
Definition: rewriteheap.c:155
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:109
#define HEAP2_XACT_MASK
Definition: htup_details.h:283
#define HeapTupleHeaderIndicatesMovedPartitions(tup)
Definition: htup_details.h:445
void * hash_search(HTAB *hashp, const void *keyPtr, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:906
#define HEAP_UPDATED
Definition: htup_details.h:209
ItemPointerData old_tid
Definition: rewriteheap.c:184
Form_pg_class rd_rel
Definition: rel.h:83
void heap_freetuple(HeapTuple htup)
Definition: heaptuple.c:1338
ItemPointerData new_tid
Definition: rewriteheap.c:193
#define HEAP_XMAX_INVALID
Definition: htup_details.h:207
HTAB * rs_unresolved_tups
Definition: rewriteheap.c:160
bool heap_freeze_tuple(HeapTupleHeader tuple, TransactionId relfrozenxid, TransactionId relminmxid, TransactionId cutoff_xid, TransactionId cutoff_multi)
Definition: heapam.c:6368
bool TransactionIdPrecedes(TransactionId id1, TransactionId id2)
Definition: transam.c:300
TransactionId rs_oldest_xmin
Definition: rewriteheap.c:149
MemoryContext rs_cxt
Definition: rewriteheap.c:157
ItemPointerData tid
Definition: rewriteheap.c:175
#define Assert(condition)
Definition: c.h:732
HTAB * rs_old_new_tid_map
Definition: rewriteheap.c:161
#define HeapTupleHeaderGetXmin(tup)
Definition: htup_details.h:313
bool ItemPointerEquals(ItemPointer pointer1, ItemPointer pointer2)
Definition: itemptr.c:29
#define ItemPointerSetInvalid(pointer)
Definition: itemptr.h:172
TransactionId xmin
Definition: rewriteheap.c:174
static void raw_heap_insert(RewriteState state, HeapTuple tup)
Definition: rewriteheap.c:631
#define HEAP_XACT_MASK
Definition: htup_details.h:218
Relation rs_old_rel
Definition: rewriteheap.c:142
OldToNewMappingData * OldToNewMapping
Definition: rewriteheap.c:196