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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 239 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().

242 {
244  MemoryContext rw_cxt;
245  MemoryContext old_cxt;
246  HASHCTL hash_ctl;
247 
248  /*
249  * To ease cleanup, make a separate context that will contain the
250  * RewriteState struct itself plus all subsidiary data.
251  */
253  "Table rewrite",
255  old_cxt = MemoryContextSwitchTo(rw_cxt);
256 
257  /* Create and fill in the state struct */
258  state = palloc0(sizeof(RewriteStateData));
259 
260  state->rs_old_rel = old_heap;
261  state->rs_new_rel = new_heap;
262  state->rs_buffer = (Page) palloc(BLCKSZ);
263  /* new_heap needn't be empty, just locked */
264  state->rs_blockno = RelationGetNumberOfBlocks(new_heap);
265  state->rs_buffer_valid = false;
266  state->rs_use_wal = use_wal;
267  state->rs_oldest_xmin = oldest_xmin;
268  state->rs_freeze_xid = freeze_xid;
269  state->rs_cutoff_multi = cutoff_multi;
270  state->rs_cxt = rw_cxt;
271 
272  /* Initialize hash tables used to track update chains */
273  memset(&hash_ctl, 0, sizeof(hash_ctl));
274  hash_ctl.keysize = sizeof(TidHashKey);
275  hash_ctl.entrysize = sizeof(UnresolvedTupData);
276  hash_ctl.hcxt = state->rs_cxt;
277 
278  state->rs_unresolved_tups =
279  hash_create("Rewrite / Unresolved ctids",
280  128, /* arbitrary initial size */
281  &hash_ctl,
283 
284  hash_ctl.entrysize = sizeof(OldToNewMappingData);
285 
286  state->rs_old_new_tid_map =
287  hash_create("Rewrite / Old to new tid map",
288  128, /* arbitrary initial size */
289  &hash_ctl,
291 
292  MemoryContextSwitchTo(old_cxt);
293 
295 
296  return state;
297 }
#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:143
MultiXactId rs_cutoff_multi
Definition: rewriteheap.c:147
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:109
Size entrysize
Definition: hsearch.h:73
Relation rs_new_rel
Definition: rewriteheap.c:135
HTAB * rs_unresolved_tups
Definition: rewriteheap.c:152
#define ALLOCSET_DEFAULT_SIZES
Definition: memutils.h:192
MemoryContext CurrentMemoryContext
Definition: mcxt.c:38
TransactionId rs_oldest_xmin
Definition: rewriteheap.c:141
#define HASH_BLOBS
Definition: hsearch.h:88
MemoryContext rs_cxt
Definition: rewriteheap.c:149
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:805
HTAB * rs_old_new_tid_map
Definition: rewriteheap.c:153
Definition: regguts.h:298
void * palloc(Size size)
Definition: mcxt.c:949
Relation rs_old_rel
Definition: rewriteheap.c:134
BlockNumber rs_blockno
Definition: rewriteheap.c:137
Pointer Page
Definition: bufpage.h:78

◆ CheckPointLogicalRewriteHeap()

void CheckPointLogicalRewriteHeap ( void  )

Definition at line 1213 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().

1214 {
1215  XLogRecPtr cutoff;
1216  XLogRecPtr redo;
1217  DIR *mappings_dir;
1218  struct dirent *mapping_de;
1219  char path[MAXPGPATH + 20];
1220 
1221  /*
1222  * We start of with a minimum of the last redo pointer. No new decoding
1223  * slot will start before that, so that's a safe upper bound for removal.
1224  */
1225  redo = GetRedoRecPtr();
1226 
1227  /* now check for the restart ptrs from existing slots */
1229 
1230  /* don't start earlier than the restart lsn */
1231  if (cutoff != InvalidXLogRecPtr && redo < cutoff)
1232  cutoff = redo;
1233 
1234  mappings_dir = AllocateDir("pg_logical/mappings");
1235  while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
1236  {
1237  struct stat statbuf;
1238  Oid dboid;
1239  Oid relid;
1240  XLogRecPtr lsn;
1241  TransactionId rewrite_xid;
1242  TransactionId create_xid;
1243  uint32 hi,
1244  lo;
1245 
1246  if (strcmp(mapping_de->d_name, ".") == 0 ||
1247  strcmp(mapping_de->d_name, "..") == 0)
1248  continue;
1249 
1250  snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
1251  if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
1252  continue;
1253 
1254  /* Skip over files that cannot be ours. */
1255  if (strncmp(mapping_de->d_name, "map-", 4) != 0)
1256  continue;
1257 
1258  if (sscanf(mapping_de->d_name, LOGICAL_REWRITE_FORMAT,
1259  &dboid, &relid, &hi, &lo, &rewrite_xid, &create_xid) != 6)
1260  elog(ERROR, "could not parse filename \"%s\"", mapping_de->d_name);
1261 
1262  lsn = ((uint64) hi) << 32 | lo;
1263 
1264  if (lsn < cutoff || cutoff == InvalidXLogRecPtr)
1265  {
1266  elog(DEBUG1, "removing logical rewrite file \"%s\"", path);
1267  if (unlink(path) < 0)
1268  ereport(ERROR,
1270  errmsg("could not remove file \"%s\": %m", path)));
1271  }
1272  else
1273  {
1274  /* on some operating systems fsyncing a file requires O_RDWR */
1275  int fd = OpenTransientFile(path, O_RDWR | PG_BINARY);
1276 
1277  /*
1278  * The file cannot vanish due to concurrency since this function
1279  * is the only one removing logical mappings and it's run while
1280  * CheckpointLock is held exclusively.
1281  */
1282  if (fd < 0)
1283  ereport(ERROR,
1285  errmsg("could not open file \"%s\": %m", path)));
1286 
1287  /*
1288  * We could try to avoid fsyncing files that either haven't
1289  * changed or have only been created since the checkpoint's start,
1290  * but it's currently not deemed worth the effort.
1291  */
1293  if (pg_fsync(fd) != 0)
1296  errmsg("could not fsync file \"%s\": %m", path)));
1298 
1299  if (CloseTransientFile(fd) != 0)
1300  ereport(ERROR,
1302  errmsg("could not close file \"%s\": %m", path)));
1303  }
1304  }
1305  FreeDir(mappings_dir);
1306 }
#define InvalidXLogRecPtr
Definition: xlogdefs.h:28
#define DEBUG1
Definition: elog.h:25
uint32 TransactionId
Definition: c.h:514
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:1222
Definition: dirent.c:25
#define ERROR
Definition: elog.h:43
int OpenTransientFile(const char *fileName, int fileFlags)
Definition: fd.c:2292
#define MAXPGPATH
int errcode_for_file_access(void)
Definition: elog.c:631
XLogRecPtr ReplicationSlotsComputeLogicalRestartLSN(void)
Definition: slot.c:791
unsigned int uint32
Definition: c.h:359
DIR * AllocateDir(const char *dirname)
Definition: fd.c:2503
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:2469
#define stat(a, b)
Definition: win32_port.h:255
int data_sync_elevel(int elevel)
Definition: fd.c:3519
uint64 XLogRecPtr
Definition: xlogdefs.h:21
struct dirent * ReadDir(DIR *dir, const char *dirname)
Definition: fd.c:2569
static void pgstat_report_wait_start(uint32 wait_event_info)
Definition: pgstat.h:1318
XLogRecPtr GetRedoRecPtr(void)
Definition: xlog.c:8208
#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:822
#define elog(elevel,...)
Definition: elog.h:228
int pg_fsync(int fd)
Definition: fd.c:330
char d_name[MAX_PATH]
Definition: dirent.h:14
#define snprintf
Definition: port.h:192
int FreeDir(DIR *dir)
Definition: fd.c:2621

◆ end_heap_rewrite()

void end_heap_rewrite ( RewriteState  state)

Definition at line 305 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().

306 {
307  HASH_SEQ_STATUS seq_status;
308  UnresolvedTup unresolved;
309 
310  /*
311  * Write any remaining tuples in the UnresolvedTups table. If we have any
312  * left, they should in fact be dead, but let's err on the safe side.
313  */
314  hash_seq_init(&seq_status, state->rs_unresolved_tups);
315 
316  while ((unresolved = hash_seq_search(&seq_status)) != NULL)
317  {
318  ItemPointerSetInvalid(&unresolved->tuple->t_data->t_ctid);
319  raw_heap_insert(state, unresolved->tuple);
320  }
321 
322  /* Write the last page, if any */
323  if (state->rs_buffer_valid)
324  {
325  if (state->rs_use_wal)
326  log_newpage(&state->rs_new_rel->rd_node,
327  MAIN_FORKNUM,
328  state->rs_blockno,
329  state->rs_buffer,
330  true);
332 
334 
336  (char *) state->rs_buffer, true);
337  }
338 
339  /*
340  * If the rel is WAL-logged, must fsync before commit. We use heap_sync
341  * to ensure that the toast table gets fsync'd too.
342  *
343  * It's obvious that we must do this when not WAL-logging. It's less
344  * obvious that we have to do it even if we did WAL-log the pages. The
345  * reason is the same as in storage.c's RelationCopyStorage(): we're
346  * writing data that's not in shared buffers, and so a CHECKPOINT
347  * occurring during the rewriteheap operation won't have fsync'd data we
348  * wrote before the checkpoint.
349  */
350  if (RelationNeedsWAL(state->rs_new_rel))
351  heap_sync(state->rs_new_rel);
352 
354 
355  /* Deleting the context frees everything */
356  MemoryContextDelete(state->rs_cxt);
357 }
void MemoryContextDelete(MemoryContext context)
Definition: mcxt.c:211
static void logical_end_heap_rewrite(RewriteState state)
Definition: rewriteheap.c:952
struct SMgrRelationData * rd_smgr
Definition: rel.h:56
Relation rs_new_rel
Definition: rewriteheap.c:135
void heap_sync(Relation rel)
Definition: heapam.c:8938
HeapTupleHeader t_data
Definition: htup.h:68
#define RelationOpenSmgr(relation)
Definition: rel.h:479
ItemPointerData t_ctid
Definition: htup_details.h:160
HTAB * rs_unresolved_tups
Definition: rewriteheap.c:152
MemoryContext rs_cxt
Definition: rewriteheap.c:149
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:524
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:623
BlockNumber rs_blockno
Definition: rewriteheap.c:137

◆ rewrite_heap_dead_tuple()

bool rewrite_heap_dead_tuple ( RewriteState  state,
HeapTuple  oldTuple 
)

Definition at line 573 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().

574 {
575  /*
576  * If we have already seen an earlier tuple in the update chain that
577  * points to this tuple, let's forget about that earlier tuple. It's in
578  * fact dead as well, our simple xmax < OldestXmin test in
579  * HeapTupleSatisfiesVacuum just wasn't enough to detect it. It happens
580  * when xmin of a tuple is greater than xmax, which sounds
581  * counter-intuitive but is perfectly valid.
582  *
583  * We don't bother to try to detect the situation the other way round,
584  * when we encounter the dead tuple first and then the recently dead one
585  * that points to it. If that happens, we'll have some unmatched entries
586  * in the UnresolvedTups hash table at the end. That can happen anyway,
587  * because a vacuum might have removed the dead tuple in the chain before
588  * us.
589  */
590  UnresolvedTup unresolved;
591  TidHashKey hashkey;
592  bool found;
593 
594  memset(&hashkey, 0, sizeof(hashkey));
595  hashkey.xmin = HeapTupleHeaderGetXmin(old_tuple->t_data);
596  hashkey.tid = old_tuple->t_self;
597 
598  unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
599  HASH_FIND, NULL);
600 
601  if (unresolved != NULL)
602  {
603  /* Need to free the contained tuple as well as the hashtable entry */
604  heap_freetuple(unresolved->tuple);
605  hash_search(state->rs_unresolved_tups, &hashkey,
606  HASH_REMOVE, &found);
607  Assert(found);
608  return true;
609  }
610 
611  return false;
612 }
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:152
ItemPointerData tid
Definition: rewriteheap.c:167
#define Assert(condition)
Definition: c.h:739
#define HeapTupleHeaderGetXmin(tup)
Definition: htup_details.h:313
TransactionId xmin
Definition: rewriteheap.c:166

◆ rewrite_heap_tuple()

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

Definition at line 371 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().

373 {
374  MemoryContext old_cxt;
375  ItemPointerData old_tid;
376  TidHashKey hashkey;
377  bool found;
378  bool free_new;
379 
380  old_cxt = MemoryContextSwitchTo(state->rs_cxt);
381 
382  /*
383  * Copy the original tuple's visibility information into new_tuple.
384  *
385  * XXX we might later need to copy some t_infomask2 bits, too? Right now,
386  * we intentionally clear the HOT status bits.
387  */
388  memcpy(&new_tuple->t_data->t_choice.t_heap,
389  &old_tuple->t_data->t_choice.t_heap,
390  sizeof(HeapTupleFields));
391 
392  new_tuple->t_data->t_infomask &= ~HEAP_XACT_MASK;
393  new_tuple->t_data->t_infomask2 &= ~HEAP2_XACT_MASK;
394  new_tuple->t_data->t_infomask |=
395  old_tuple->t_data->t_infomask & HEAP_XACT_MASK;
396 
397  /*
398  * While we have our hands on the tuple, we may as well freeze any
399  * eligible xmin or xmax, so that future VACUUM effort can be saved.
400  */
401  heap_freeze_tuple(new_tuple->t_data,
402  state->rs_old_rel->rd_rel->relfrozenxid,
403  state->rs_old_rel->rd_rel->relminmxid,
404  state->rs_freeze_xid,
405  state->rs_cutoff_multi);
406 
407  /*
408  * Invalid ctid means that ctid should point to the tuple itself. We'll
409  * override it later if the tuple is part of an update chain.
410  */
411  ItemPointerSetInvalid(&new_tuple->t_data->t_ctid);
412 
413  /*
414  * If the tuple has been updated, check the old-to-new mapping hash table.
415  */
416  if (!((old_tuple->t_data->t_infomask & HEAP_XMAX_INVALID) ||
417  HeapTupleHeaderIsOnlyLocked(old_tuple->t_data)) &&
418  !HeapTupleHeaderIndicatesMovedPartitions(old_tuple->t_data) &&
419  !(ItemPointerEquals(&(old_tuple->t_self),
420  &(old_tuple->t_data->t_ctid))))
421  {
422  OldToNewMapping mapping;
423 
424  memset(&hashkey, 0, sizeof(hashkey));
425  hashkey.xmin = HeapTupleHeaderGetUpdateXid(old_tuple->t_data);
426  hashkey.tid = old_tuple->t_data->t_ctid;
427 
428  mapping = (OldToNewMapping)
429  hash_search(state->rs_old_new_tid_map, &hashkey,
430  HASH_FIND, NULL);
431 
432  if (mapping != NULL)
433  {
434  /*
435  * We've already copied the tuple that t_ctid points to, so we can
436  * set the ctid of this tuple to point to the new location, and
437  * insert it right away.
438  */
439  new_tuple->t_data->t_ctid = mapping->new_tid;
440 
441  /* We don't need the mapping entry anymore */
442  hash_search(state->rs_old_new_tid_map, &hashkey,
443  HASH_REMOVE, &found);
444  Assert(found);
445  }
446  else
447  {
448  /*
449  * We haven't seen the tuple t_ctid points to yet. Stash this
450  * tuple into unresolved_tups to be written later.
451  */
452  UnresolvedTup unresolved;
453 
454  unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
455  HASH_ENTER, &found);
456  Assert(!found);
457 
458  unresolved->old_tid = old_tuple->t_self;
459  unresolved->tuple = heap_copytuple(new_tuple);
460 
461  /*
462  * We can't do anything more now, since we don't know where the
463  * tuple will be written.
464  */
465  MemoryContextSwitchTo(old_cxt);
466  return;
467  }
468  }
469 
470  /*
471  * Now we will write the tuple, and then check to see if it is the B tuple
472  * in any new or known pair. When we resolve a known pair, we will be
473  * able to write that pair's A tuple, and then we have to check if it
474  * resolves some other pair. Hence, we need a loop here.
475  */
476  old_tid = old_tuple->t_self;
477  free_new = false;
478 
479  for (;;)
480  {
481  ItemPointerData new_tid;
482 
483  /* Insert the tuple and find out where it's put in new_heap */
484  raw_heap_insert(state, new_tuple);
485  new_tid = new_tuple->t_self;
486 
487  logical_rewrite_heap_tuple(state, old_tid, new_tuple);
488 
489  /*
490  * If the tuple is the updated version of a row, and the prior version
491  * wouldn't be DEAD yet, then we need to either resolve the prior
492  * version (if it's waiting in rs_unresolved_tups), or make an entry
493  * in rs_old_new_tid_map (so we can resolve it when we do see it). The
494  * previous tuple's xmax would equal this one's xmin, so it's
495  * RECENTLY_DEAD if and only if the xmin is not before OldestXmin.
496  */
497  if ((new_tuple->t_data->t_infomask & HEAP_UPDATED) &&
498  !TransactionIdPrecedes(HeapTupleHeaderGetXmin(new_tuple->t_data),
499  state->rs_oldest_xmin))
500  {
501  /*
502  * Okay, this is B in an update pair. See if we've seen A.
503  */
504  UnresolvedTup unresolved;
505 
506  memset(&hashkey, 0, sizeof(hashkey));
507  hashkey.xmin = HeapTupleHeaderGetXmin(new_tuple->t_data);
508  hashkey.tid = old_tid;
509 
510  unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
511  HASH_FIND, NULL);
512 
513  if (unresolved != NULL)
514  {
515  /*
516  * We have seen and memorized the previous tuple already. Now
517  * that we know where we inserted the tuple its t_ctid points
518  * to, fix its t_ctid and insert it to the new heap.
519  */
520  if (free_new)
521  heap_freetuple(new_tuple);
522  new_tuple = unresolved->tuple;
523  free_new = true;
524  old_tid = unresolved->old_tid;
525  new_tuple->t_data->t_ctid = new_tid;
526 
527  /*
528  * We don't need the hash entry anymore, but don't free its
529  * tuple just yet.
530  */
531  hash_search(state->rs_unresolved_tups, &hashkey,
532  HASH_REMOVE, &found);
533  Assert(found);
534 
535  /* loop back to insert the previous tuple in the chain */
536  continue;
537  }
538  else
539  {
540  /*
541  * Remember the new tid of this tuple. We'll use it to set the
542  * ctid when we find the previous tuple in the chain.
543  */
544  OldToNewMapping mapping;
545 
546  mapping = hash_search(state->rs_old_new_tid_map, &hashkey,
547  HASH_ENTER, &found);
548  Assert(!found);
549 
550  mapping->new_tid = new_tid;
551  }
552  }
553 
554  /* Done with this (chain of) tuples, for now */
555  if (free_new)
556  heap_freetuple(new_tuple);
557  break;
558  }
559 
560  MemoryContextSwitchTo(old_cxt);
561 }
#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:1049
TransactionId rs_freeze_xid
Definition: rewriteheap.c:143
bool HeapTupleHeaderIsOnlyLocked(HeapTupleHeader tuple)
MultiXactId rs_cutoff_multi
Definition: rewriteheap.c:147
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:176
Form_pg_class rd_rel
Definition: rel.h:83
void heap_freetuple(HeapTuple htup)
Definition: heaptuple.c:1338
ItemPointerData new_tid
Definition: rewriteheap.c:185
#define HEAP_XMAX_INVALID
Definition: htup_details.h:207
HTAB * rs_unresolved_tups
Definition: rewriteheap.c:152
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:141
MemoryContext rs_cxt
Definition: rewriteheap.c:149
ItemPointerData tid
Definition: rewriteheap.c:167
#define Assert(condition)
Definition: c.h:739
HTAB * rs_old_new_tid_map
Definition: rewriteheap.c:153
#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:166
static void raw_heap_insert(RewriteState state, HeapTuple tup)
Definition: rewriteheap.c:623
#define HEAP_XACT_MASK
Definition: htup_details.h:218
Relation rs_old_rel
Definition: rewriteheap.c:134
OldToNewMappingData * OldToNewMapping
Definition: rewriteheap.c:188