PostgreSQL Source Code  git master
multixact.h File Reference
#include "access/xlogreader.h"
#include "lib/stringinfo.h"
#include "storage/sync.h"
Include dependency graph for multixact.h:
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Data Structures

struct  MultiXactMember
 
struct  xl_multixact_create
 
struct  xl_multixact_truncate
 

Macros

#define InvalidMultiXactId   ((MultiXactId) 0)
 
#define FirstMultiXactId   ((MultiXactId) 1)
 
#define MaxMultiXactId   ((MultiXactId) 0xFFFFFFFF)
 
#define MultiXactIdIsValid(multi)   ((multi) != InvalidMultiXactId)
 
#define MaxMultiXactOffset   ((MultiXactOffset) 0xFFFFFFFF)
 
#define NUM_MULTIXACTOFFSET_BUFFERS   8
 
#define NUM_MULTIXACTMEMBER_BUFFERS   16
 
#define MaxMultiXactStatus   MultiXactStatusUpdate
 
#define ISUPDATE_from_mxstatus(status)    ((status) > MultiXactStatusForUpdate)
 
#define XLOG_MULTIXACT_ZERO_OFF_PAGE   0x00
 
#define XLOG_MULTIXACT_ZERO_MEM_PAGE   0x10
 
#define XLOG_MULTIXACT_CREATE_ID   0x20
 
#define XLOG_MULTIXACT_TRUNCATE_ID   0x30
 
#define SizeOfMultiXactCreate   (offsetof(xl_multixact_create, members))
 
#define SizeOfMultiXactTruncate   (sizeof(xl_multixact_truncate))
 

Typedefs

typedef struct MultiXactMember MultiXactMember
 
typedef struct xl_multixact_create xl_multixact_create
 
typedef struct xl_multixact_truncate xl_multixact_truncate
 

Enumerations

enum  MultiXactStatus {
  MultiXactStatusForKeyShare = 0x00 , MultiXactStatusForShare = 0x01 , MultiXactStatusForNoKeyUpdate = 0x02 , MultiXactStatusForUpdate = 0x03 ,
  MultiXactStatusNoKeyUpdate = 0x04 , MultiXactStatusUpdate = 0x05
}
 

Functions

MultiXactId MultiXactIdCreate (TransactionId xid1, MultiXactStatus status1, TransactionId xid2, MultiXactStatus status2)
 
MultiXactId MultiXactIdExpand (MultiXactId multi, TransactionId xid, MultiXactStatus status)
 
MultiXactId MultiXactIdCreateFromMembers (int nmembers, MultiXactMember *members)
 
MultiXactId ReadNextMultiXactId (void)
 
void ReadMultiXactIdRange (MultiXactId *oldest, MultiXactId *next)
 
bool MultiXactIdIsRunning (MultiXactId multi, bool isLockOnly)
 
void MultiXactIdSetOldestMember (void)
 
int GetMultiXactIdMembers (MultiXactId multi, MultiXactMember **members, bool from_pgupgrade, bool isLockOnly)
 
bool MultiXactIdPrecedes (MultiXactId multi1, MultiXactId multi2)
 
bool MultiXactIdPrecedesOrEquals (MultiXactId multi1, MultiXactId multi2)
 
int multixactoffsetssyncfiletag (const FileTag *ftag, char *path)
 
int multixactmemberssyncfiletag (const FileTag *ftag, char *path)
 
void AtEOXact_MultiXact (void)
 
void AtPrepare_MultiXact (void)
 
void PostPrepare_MultiXact (TransactionId xid)
 
Size MultiXactShmemSize (void)
 
void MultiXactShmemInit (void)
 
void BootStrapMultiXact (void)
 
void StartupMultiXact (void)
 
void TrimMultiXact (void)
 
void SetMultiXactIdLimit (MultiXactId oldest_datminmxid, Oid oldest_datoid, bool is_startup)
 
void MultiXactGetCheckptMulti (bool is_shutdown, MultiXactId *nextMulti, MultiXactOffset *nextMultiOffset, MultiXactId *oldestMulti, Oid *oldestMultiDB)
 
void CheckPointMultiXact (void)
 
MultiXactId GetOldestMultiXactId (void)
 
void TruncateMultiXact (MultiXactId newOldestMulti, Oid newOldestMultiDB)
 
void MultiXactSetNextMXact (MultiXactId nextMulti, MultiXactOffset nextMultiOffset)
 
void MultiXactAdvanceNextMXact (MultiXactId minMulti, MultiXactOffset minMultiOffset)
 
void MultiXactAdvanceOldest (MultiXactId oldestMulti, Oid oldestMultiDB)
 
int MultiXactMemberFreezeThreshold (void)
 
void multixact_twophase_recover (TransactionId xid, uint16 info, void *recdata, uint32 len)
 
void multixact_twophase_postcommit (TransactionId xid, uint16 info, void *recdata, uint32 len)
 
void multixact_twophase_postabort (TransactionId xid, uint16 info, void *recdata, uint32 len)
 
void multixact_redo (XLogReaderState *record)
 
void multixact_desc (StringInfo buf, XLogReaderState *record)
 
const char * multixact_identify (uint8 info)
 
char * mxid_to_string (MultiXactId multi, int nmembers, MultiXactMember *members)
 

Macro Definition Documentation

◆ FirstMultiXactId

#define FirstMultiXactId   ((MultiXactId) 1)

Definition at line 25 of file multixact.h.

◆ InvalidMultiXactId

#define InvalidMultiXactId   ((MultiXactId) 0)

Definition at line 24 of file multixact.h.

◆ ISUPDATE_from_mxstatus

#define ISUPDATE_from_mxstatus (   status)     ((status) > MultiXactStatusForUpdate)

Definition at line 56 of file multixact.h.

◆ MaxMultiXactId

#define MaxMultiXactId   ((MultiXactId) 0xFFFFFFFF)

Definition at line 26 of file multixact.h.

◆ MaxMultiXactOffset

#define MaxMultiXactOffset   ((MultiXactOffset) 0xFFFFFFFF)

Definition at line 30 of file multixact.h.

◆ MaxMultiXactStatus

#define MaxMultiXactStatus   MultiXactStatusUpdate

Definition at line 53 of file multixact.h.

◆ MultiXactIdIsValid

#define MultiXactIdIsValid (   multi)    ((multi) != InvalidMultiXactId)

Definition at line 28 of file multixact.h.

◆ NUM_MULTIXACTMEMBER_BUFFERS

#define NUM_MULTIXACTMEMBER_BUFFERS   16

Definition at line 34 of file multixact.h.

◆ NUM_MULTIXACTOFFSET_BUFFERS

#define NUM_MULTIXACTOFFSET_BUFFERS   8

Definition at line 33 of file multixact.h.

◆ SizeOfMultiXactCreate

#define SizeOfMultiXactCreate   (offsetof(xl_multixact_create, members))

Definition at line 85 of file multixact.h.

◆ SizeOfMultiXactTruncate

#define SizeOfMultiXactTruncate   (sizeof(xl_multixact_truncate))

Definition at line 100 of file multixact.h.

◆ XLOG_MULTIXACT_CREATE_ID

#define XLOG_MULTIXACT_CREATE_ID   0x20

Definition at line 74 of file multixact.h.

◆ XLOG_MULTIXACT_TRUNCATE_ID

#define XLOG_MULTIXACT_TRUNCATE_ID   0x30

Definition at line 75 of file multixact.h.

◆ XLOG_MULTIXACT_ZERO_MEM_PAGE

#define XLOG_MULTIXACT_ZERO_MEM_PAGE   0x10

Definition at line 73 of file multixact.h.

◆ XLOG_MULTIXACT_ZERO_OFF_PAGE

#define XLOG_MULTIXACT_ZERO_OFF_PAGE   0x00

Definition at line 72 of file multixact.h.

Typedef Documentation

◆ MultiXactMember

◆ xl_multixact_create

◆ xl_multixact_truncate

Enumeration Type Documentation

◆ MultiXactStatus

Enumerator
MultiXactStatusForKeyShare 
MultiXactStatusForShare 
MultiXactStatusForNoKeyUpdate 
MultiXactStatusForUpdate 
MultiXactStatusNoKeyUpdate 
MultiXactStatusUpdate 

Definition at line 41 of file multixact.h.

42 {
47  /* an update that doesn't touch "key" columns */
49  /* other updates, and delete */
MultiXactStatus
Definition: multixact.h:42
@ MultiXactStatusForShare
Definition: multixact.h:44
@ MultiXactStatusForNoKeyUpdate
Definition: multixact.h:45
@ MultiXactStatusNoKeyUpdate
Definition: multixact.h:48
@ MultiXactStatusUpdate
Definition: multixact.h:50
@ MultiXactStatusForUpdate
Definition: multixact.h:46
@ MultiXactStatusForKeyShare
Definition: multixact.h:43

Function Documentation

◆ AtEOXact_MultiXact()

void AtEOXact_MultiXact ( void  )

Definition at line 1688 of file multixact.c.

1689 {
1690  /*
1691  * Reset our OldestMemberMXactId and OldestVisibleMXactId values, both of
1692  * which should only be valid while within a transaction.
1693  *
1694  * We assume that storing a MultiXactId is atomic and so we need not take
1695  * MultiXactGenLock to do this.
1696  */
1699 
1700  /*
1701  * Discard the local MultiXactId cache. Since MXactContext was created as
1702  * a child of TopTransactionContext, we needn't delete it explicitly.
1703  */
1704  MXactContext = NULL;
1706 }
BackendId MyBackendId
Definition: globals.c:85
static void dclist_init(dclist_head *head)
Definition: ilist.h:671
static MemoryContext MXactContext
Definition: multixact.c:325
static MultiXactId * OldestVisibleMXactId
Definition: multixact.c:295
static dclist_head MXactCache
Definition: multixact.c:324
static MultiXactId * OldestMemberMXactId
Definition: multixact.c:294
#define InvalidMultiXactId
Definition: multixact.h:24

References dclist_init(), InvalidMultiXactId, MXactCache, MXactContext, MyBackendId, OldestMemberMXactId, and OldestVisibleMXactId.

Referenced by AbortTransaction(), and CommitTransaction().

◆ AtPrepare_MultiXact()

void AtPrepare_MultiXact ( void  )

Definition at line 1716 of file multixact.c.

1717 {
1718  MultiXactId myOldestMember = OldestMemberMXactId[MyBackendId];
1719 
1720  if (MultiXactIdIsValid(myOldestMember))
1722  &myOldestMember, sizeof(MultiXactId));
1723 }
TransactionId MultiXactId
Definition: c.h:646
#define MultiXactIdIsValid(multi)
Definition: multixact.h:28
void RegisterTwoPhaseRecord(TwoPhaseRmgrId rmid, uint16 info, const void *data, uint32 len)
Definition: twophase.c:1257
#define TWOPHASE_RM_MULTIXACT_ID
Definition: twophase_rmgr.h:27

References MultiXactIdIsValid, MyBackendId, OldestMemberMXactId, RegisterTwoPhaseRecord(), and TWOPHASE_RM_MULTIXACT_ID.

Referenced by PrepareTransaction().

◆ BootStrapMultiXact()

void BootStrapMultiXact ( void  )

Definition at line 1894 of file multixact.c.

1895 {
1896  int slotno;
1897 
1898  LWLockAcquire(MultiXactOffsetSLRULock, LW_EXCLUSIVE);
1899 
1900  /* Create and zero the first page of the offsets log */
1901  slotno = ZeroMultiXactOffsetPage(0, false);
1902 
1903  /* Make sure it's written out */
1905  Assert(!MultiXactOffsetCtl->shared->page_dirty[slotno]);
1906 
1907  LWLockRelease(MultiXactOffsetSLRULock);
1908 
1909  LWLockAcquire(MultiXactMemberSLRULock, LW_EXCLUSIVE);
1910 
1911  /* Create and zero the first page of the members log */
1912  slotno = ZeroMultiXactMemberPage(0, false);
1913 
1914  /* Make sure it's written out */
1916  Assert(!MultiXactMemberCtl->shared->page_dirty[slotno]);
1917 
1918  LWLockRelease(MultiXactMemberSLRULock);
1919 }
Assert(fmt[strlen(fmt) - 1] !='\n')
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1195
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1803
@ LW_EXCLUSIVE
Definition: lwlock.h:115
static int ZeroMultiXactMemberPage(int pageno, bool writeXlog)
Definition: multixact.c:1947
static int ZeroMultiXactOffsetPage(int pageno, bool writeXlog)
Definition: multixact.c:1931
#define MultiXactMemberCtl
Definition: multixact.c:191
#define MultiXactOffsetCtl
Definition: multixact.c:190
void SimpleLruWritePage(SlruCtl ctl, int slotno)
Definition: slru.c:615

References Assert(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MultiXactMemberCtl, MultiXactOffsetCtl, SimpleLruWritePage(), ZeroMultiXactMemberPage(), and ZeroMultiXactOffsetPage().

Referenced by BootStrapXLOG().

◆ CheckPointMultiXact()

void CheckPointMultiXact ( void  )

Definition at line 2155 of file multixact.c.

2156 {
2157  TRACE_POSTGRESQL_MULTIXACT_CHECKPOINT_START(true);
2158 
2159  /*
2160  * Write dirty MultiXact pages to disk. This may result in sync requests
2161  * queued for later handling by ProcessSyncRequests(), as part of the
2162  * checkpoint.
2163  */
2166 
2167  TRACE_POSTGRESQL_MULTIXACT_CHECKPOINT_DONE(true);
2168 }
void SimpleLruWriteAll(SlruCtl ctl, bool allow_redirtied)
Definition: slru.c:1157

References MultiXactMemberCtl, MultiXactOffsetCtl, and SimpleLruWriteAll().

Referenced by CheckPointGuts().

◆ GetMultiXactIdMembers()

int GetMultiXactIdMembers ( MultiXactId  multi,
MultiXactMember **  members,
bool  from_pgupgrade,
bool  isLockOnly 
)

Definition at line 1225 of file multixact.c.

1227 {
1228  int pageno;
1229  int prev_pageno;
1230  int entryno;
1231  int slotno;
1232  MultiXactOffset *offptr;
1233  MultiXactOffset offset;
1234  int length;
1235  int truelength;
1236  int i;
1237  MultiXactId oldestMXact;
1238  MultiXactId nextMXact;
1239  MultiXactId tmpMXact;
1240  MultiXactOffset nextOffset;
1241  MultiXactMember *ptr;
1242 
1243  debug_elog3(DEBUG2, "GetMembers: asked for %u", multi);
1244 
1245  if (!MultiXactIdIsValid(multi) || from_pgupgrade)
1246  {
1247  *members = NULL;
1248  return -1;
1249  }
1250 
1251  /* See if the MultiXactId is in the local cache */
1252  length = mXactCacheGetById(multi, members);
1253  if (length >= 0)
1254  {
1255  debug_elog3(DEBUG2, "GetMembers: found %s in the cache",
1256  mxid_to_string(multi, length, *members));
1257  return length;
1258  }
1259 
1260  /* Set our OldestVisibleMXactId[] entry if we didn't already */
1262 
1263  /*
1264  * If we know the multi is used only for locking and not for updates, then
1265  * we can skip checking if the value is older than our oldest visible
1266  * multi. It cannot possibly still be running.
1267  */
1268  if (isLockOnly &&
1270  {
1271  debug_elog2(DEBUG2, "GetMembers: a locker-only multi is too old");
1272  *members = NULL;
1273  return -1;
1274  }
1275 
1276  /*
1277  * We check known limits on MultiXact before resorting to the SLRU area.
1278  *
1279  * An ID older than MultiXactState->oldestMultiXactId cannot possibly be
1280  * useful; it has already been removed, or will be removed shortly, by
1281  * truncation. If one is passed, an error is raised.
1282  *
1283  * Also, an ID >= nextMXact shouldn't ever be seen here; if it is seen, it
1284  * implies undetected ID wraparound has occurred. This raises a hard
1285  * error.
1286  *
1287  * Shared lock is enough here since we aren't modifying any global state.
1288  * Acquire it just long enough to grab the current counter values. We may
1289  * need both nextMXact and nextOffset; see below.
1290  */
1291  LWLockAcquire(MultiXactGenLock, LW_SHARED);
1292 
1293  oldestMXact = MultiXactState->oldestMultiXactId;
1294  nextMXact = MultiXactState->nextMXact;
1295  nextOffset = MultiXactState->nextOffset;
1296 
1297  LWLockRelease(MultiXactGenLock);
1298 
1299  if (MultiXactIdPrecedes(multi, oldestMXact))
1300  ereport(ERROR,
1301  (errcode(ERRCODE_INTERNAL_ERROR),
1302  errmsg("MultiXactId %u does no longer exist -- apparent wraparound",
1303  multi)));
1304 
1305  if (!MultiXactIdPrecedes(multi, nextMXact))
1306  ereport(ERROR,
1307  (errcode(ERRCODE_INTERNAL_ERROR),
1308  errmsg("MultiXactId %u has not been created yet -- apparent wraparound",
1309  multi)));
1310 
1311  /*
1312  * Find out the offset at which we need to start reading MultiXactMembers
1313  * and the number of members in the multixact. We determine the latter as
1314  * the difference between this multixact's starting offset and the next
1315  * one's. However, there are some corner cases to worry about:
1316  *
1317  * 1. This multixact may be the latest one created, in which case there is
1318  * no next one to look at. In this case the nextOffset value we just
1319  * saved is the correct endpoint.
1320  *
1321  * 2. The next multixact may still be in process of being filled in: that
1322  * is, another process may have done GetNewMultiXactId but not yet written
1323  * the offset entry for that ID. In that scenario, it is guaranteed that
1324  * the offset entry for that multixact exists (because GetNewMultiXactId
1325  * won't release MultiXactGenLock until it does) but contains zero
1326  * (because we are careful to pre-zero offset pages). Because
1327  * GetNewMultiXactId will never return zero as the starting offset for a
1328  * multixact, when we read zero as the next multixact's offset, we know we
1329  * have this case. We sleep for a bit and try again.
1330  *
1331  * 3. Because GetNewMultiXactId increments offset zero to offset one to
1332  * handle case #2, there is an ambiguity near the point of offset
1333  * wraparound. If we see next multixact's offset is one, is that our
1334  * multixact's actual endpoint, or did it end at zero with a subsequent
1335  * increment? We handle this using the knowledge that if the zero'th
1336  * member slot wasn't filled, it'll contain zero, and zero isn't a valid
1337  * transaction ID so it can't be a multixact member. Therefore, if we
1338  * read a zero from the members array, just ignore it.
1339  *
1340  * This is all pretty messy, but the mess occurs only in infrequent corner
1341  * cases, so it seems better than holding the MultiXactGenLock for a long
1342  * time on every multixact creation.
1343  */
1344 retry:
1345  LWLockAcquire(MultiXactOffsetSLRULock, LW_EXCLUSIVE);
1346 
1347  pageno = MultiXactIdToOffsetPage(multi);
1348  entryno = MultiXactIdToOffsetEntry(multi);
1349 
1350  slotno = SimpleLruReadPage(MultiXactOffsetCtl, pageno, true, multi);
1351  offptr = (MultiXactOffset *) MultiXactOffsetCtl->shared->page_buffer[slotno];
1352  offptr += entryno;
1353  offset = *offptr;
1354 
1355  Assert(offset != 0);
1356 
1357  /*
1358  * Use the same increment rule as GetNewMultiXactId(), that is, don't
1359  * handle wraparound explicitly until needed.
1360  */
1361  tmpMXact = multi + 1;
1362 
1363  if (nextMXact == tmpMXact)
1364  {
1365  /* Corner case 1: there is no next multixact */
1366  length = nextOffset - offset;
1367  }
1368  else
1369  {
1370  MultiXactOffset nextMXOffset;
1371 
1372  /* handle wraparound if needed */
1373  if (tmpMXact < FirstMultiXactId)
1374  tmpMXact = FirstMultiXactId;
1375 
1376  prev_pageno = pageno;
1377 
1378  pageno = MultiXactIdToOffsetPage(tmpMXact);
1379  entryno = MultiXactIdToOffsetEntry(tmpMXact);
1380 
1381  if (pageno != prev_pageno)
1382  slotno = SimpleLruReadPage(MultiXactOffsetCtl, pageno, true, tmpMXact);
1383 
1384  offptr = (MultiXactOffset *) MultiXactOffsetCtl->shared->page_buffer[slotno];
1385  offptr += entryno;
1386  nextMXOffset = *offptr;
1387 
1388  if (nextMXOffset == 0)
1389  {
1390  /* Corner case 2: next multixact is still being filled in */
1391  LWLockRelease(MultiXactOffsetSLRULock);
1393  pg_usleep(1000L);
1394  goto retry;
1395  }
1396 
1397  length = nextMXOffset - offset;
1398  }
1399 
1400  LWLockRelease(MultiXactOffsetSLRULock);
1401 
1402  ptr = (MultiXactMember *) palloc(length * sizeof(MultiXactMember));
1403 
1404  /* Now get the members themselves. */
1405  LWLockAcquire(MultiXactMemberSLRULock, LW_EXCLUSIVE);
1406 
1407  truelength = 0;
1408  prev_pageno = -1;
1409  for (i = 0; i < length; i++, offset++)
1410  {
1411  TransactionId *xactptr;
1412  uint32 *flagsptr;
1413  int flagsoff;
1414  int bshift;
1415  int memberoff;
1416 
1417  pageno = MXOffsetToMemberPage(offset);
1418  memberoff = MXOffsetToMemberOffset(offset);
1419 
1420  if (pageno != prev_pageno)
1421  {
1422  slotno = SimpleLruReadPage(MultiXactMemberCtl, pageno, true, multi);
1423  prev_pageno = pageno;
1424  }
1425 
1426  xactptr = (TransactionId *)
1427  (MultiXactMemberCtl->shared->page_buffer[slotno] + memberoff);
1428 
1429  if (!TransactionIdIsValid(*xactptr))
1430  {
1431  /* Corner case 3: we must be looking at unused slot zero */
1432  Assert(offset == 0);
1433  continue;
1434  }
1435 
1436  flagsoff = MXOffsetToFlagsOffset(offset);
1437  bshift = MXOffsetToFlagsBitShift(offset);
1438  flagsptr = (uint32 *) (MultiXactMemberCtl->shared->page_buffer[slotno] + flagsoff);
1439 
1440  ptr[truelength].xid = *xactptr;
1441  ptr[truelength].status = (*flagsptr >> bshift) & MXACT_MEMBER_XACT_BITMASK;
1442  truelength++;
1443  }
1444 
1445  LWLockRelease(MultiXactMemberSLRULock);
1446 
1447  /* A multixid with zero members should not happen */
1448  Assert(truelength > 0);
1449 
1450  /*
1451  * Copy the result into the local cache.
1452  */
1453  mXactCachePut(multi, truelength, ptr);
1454 
1455  debug_elog3(DEBUG2, "GetMembers: no cache for %s",
1456  mxid_to_string(multi, truelength, ptr));
1457  *members = ptr;
1458  return truelength;
1459 }
unsigned int uint32
Definition: c.h:490
uint32 MultiXactOffset
Definition: c.h:648
uint32 TransactionId
Definition: c.h:636
int errcode(int sqlerrcode)
Definition: elog.c:858
int errmsg(const char *fmt,...)
Definition: elog.c:1069
#define DEBUG2
Definition: elog.h:29
#define ERROR
Definition: elog.h:39
#define ereport(elevel,...)
Definition: elog.h:149
int i
Definition: isn.c:73
if(TABLE==NULL||TABLE_index==NULL)
Definition: isn.c:77
@ LW_SHARED
Definition: lwlock.h:116
void * palloc(Size size)
Definition: mcxt.c:1210
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:121
#define MXOffsetToMemberPage(xid)
Definition: multixact.c:159
static int mXactCacheGetById(MultiXactId multi, MultiXactMember **members)
Definition: multixact.c:1542
#define MXACT_MEMBER_XACT_BITMASK
Definition: multixact.c:132
#define MultiXactIdToOffsetEntry(xid)
Definition: multixact.c:113
bool MultiXactIdPrecedes(MultiXactId multi1, MultiXactId multi2)
Definition: multixact.c:3156
static void MultiXactIdSetOldestVisible(void)
Definition: multixact.c:683
#define MXOffsetToFlagsBitShift(xid)
Definition: multixact.c:167
static void mXactCachePut(MultiXactId multi, int nmembers, MultiXactMember *members)
Definition: multixact.c:1589
#define MXOffsetToFlagsOffset(xid)
Definition: multixact.c:163
#define MXOffsetToMemberOffset(xid)
Definition: multixact.c:172
char * mxid_to_string(MultiXactId multi, int nmembers, MultiXactMember *members)
Definition: multixact.c:1657
#define debug_elog3(a, b, c)
Definition: multixact.c:335
static MultiXactStateData * MultiXactState
Definition: multixact.c:293
#define MultiXactIdToOffsetPage(xid)
Definition: multixact.c:111
#define debug_elog2(a, b)
Definition: multixact.c:334
#define FirstMultiXactId
Definition: multixact.h:25
void pg_usleep(long microsec)
Definition: signal.c:53
int SimpleLruReadPage(SlruCtl ctl, int pageno, bool write_ok, TransactionId xid)
Definition: slru.c:396
TransactionId xid
Definition: multixact.h:62
MultiXactStatus status
Definition: multixact.h:63
MultiXactOffset nextOffset
Definition: multixact.c:206
MultiXactId nextMXact
Definition: multixact.c:203
MultiXactId oldestMultiXactId
Definition: multixact.c:216
#define TransactionIdIsValid(xid)
Definition: transam.h:41

References Assert(), CHECK_FOR_INTERRUPTS, DEBUG2, debug_elog2, debug_elog3, ereport, errcode(), errmsg(), ERROR, FirstMultiXactId, i, if(), LW_EXCLUSIVE, LW_SHARED, LWLockAcquire(), LWLockRelease(), MultiXactIdIsValid, MultiXactIdPrecedes(), MultiXactIdSetOldestVisible(), MultiXactIdToOffsetEntry, MultiXactIdToOffsetPage, MultiXactMemberCtl, MultiXactOffsetCtl, MultiXactState, MXACT_MEMBER_XACT_BITMASK, mXactCacheGetById(), mXactCachePut(), mxid_to_string(), MXOffsetToFlagsBitShift, MXOffsetToFlagsOffset, MXOffsetToMemberOffset, MXOffsetToMemberPage, MyBackendId, MultiXactStateData::nextMXact, MultiXactStateData::nextOffset, MultiXactStateData::oldestMultiXactId, OldestVisibleMXactId, palloc(), pg_usleep(), SimpleLruReadPage(), MultiXactMember::status, TransactionIdIsValid, and MultiXactMember::xid.

Referenced by Do_MultiXactIdWait(), DoesMultiXactIdConflict(), FreezeMultiXactId(), GetMultiXactIdHintBits(), heap_lock_tuple(), heap_lock_updated_tuple_rec(), heap_tuple_should_freeze(), MultiXactIdExpand(), MultiXactIdGetUpdateXid(), MultiXactIdIsRunning(), pg_get_multixact_members(), and pgrowlocks().

◆ GetOldestMultiXactId()

MultiXactId GetOldestMultiXactId ( void  )

Definition at line 2507 of file multixact.c.

2508 {
2509  MultiXactId oldestMXact;
2510  MultiXactId nextMXact;
2511  int i;
2512 
2513  /*
2514  * This is the oldest valid value among all the OldestMemberMXactId[] and
2515  * OldestVisibleMXactId[] entries, or nextMXact if none are valid.
2516  */
2517  LWLockAcquire(MultiXactGenLock, LW_SHARED);
2518 
2519  /*
2520  * We have to beware of the possibility that nextMXact is in the
2521  * wrapped-around state. We don't fix the counter itself here, but we
2522  * must be sure to use a valid value in our calculation.
2523  */
2524  nextMXact = MultiXactState->nextMXact;
2525  if (nextMXact < FirstMultiXactId)
2526  nextMXact = FirstMultiXactId;
2527 
2528  oldestMXact = nextMXact;
2529  for (i = 1; i <= MaxOldestSlot; i++)
2530  {
2531  MultiXactId thisoldest;
2532 
2533  thisoldest = OldestMemberMXactId[i];
2534  if (MultiXactIdIsValid(thisoldest) &&
2535  MultiXactIdPrecedes(thisoldest, oldestMXact))
2536  oldestMXact = thisoldest;
2537  thisoldest = OldestVisibleMXactId[i];
2538  if (MultiXactIdIsValid(thisoldest) &&
2539  MultiXactIdPrecedes(thisoldest, oldestMXact))
2540  oldestMXact = thisoldest;
2541  }
2542 
2543  LWLockRelease(MultiXactGenLock);
2544 
2545  return oldestMXact;
2546 }
#define MaxOldestSlot
Definition: multixact.c:290

References FirstMultiXactId, i, LW_SHARED, LWLockAcquire(), LWLockRelease(), MaxOldestSlot, MultiXactIdIsValid, MultiXactIdPrecedes(), MultiXactState, MultiXactStateData::nextMXact, OldestMemberMXactId, and OldestVisibleMXactId.

Referenced by heapam_relation_set_new_filelocator(), vac_update_datfrozenxid(), and vacuum_get_cutoffs().

◆ multixact_desc()

void multixact_desc ( StringInfo  buf,
XLogReaderState record 
)

Definition at line 50 of file mxactdesc.c.

51 {
52  char *rec = XLogRecGetData(record);
53  uint8 info = XLogRecGetInfo(record) & ~XLR_INFO_MASK;
54 
55  if (info == XLOG_MULTIXACT_ZERO_OFF_PAGE ||
57  {
58  int pageno;
59 
60  memcpy(&pageno, rec, sizeof(int));
61  appendStringInfo(buf, "%d", pageno);
62  }
63  else if (info == XLOG_MULTIXACT_CREATE_ID)
64  {
66  int i;
67 
68  appendStringInfo(buf, "%u offset %u nmembers %d: ", xlrec->mid,
69  xlrec->moff, xlrec->nmembers);
70  for (i = 0; i < xlrec->nmembers; i++)
71  out_member(buf, &xlrec->members[i]);
72  }
73  else if (info == XLOG_MULTIXACT_TRUNCATE_ID)
74  {
76 
77  appendStringInfo(buf, "offsets [%u, %u), members [%u, %u)",
78  xlrec->startTruncOff, xlrec->endTruncOff,
79  xlrec->startTruncMemb, xlrec->endTruncMemb);
80  }
81 }
unsigned char uint8
Definition: c.h:488
#define XLOG_MULTIXACT_ZERO_MEM_PAGE
Definition: multixact.h:73
#define XLOG_MULTIXACT_ZERO_OFF_PAGE
Definition: multixact.h:72
#define XLOG_MULTIXACT_TRUNCATE_ID
Definition: multixact.h:75
#define XLOG_MULTIXACT_CREATE_ID
Definition: multixact.h:74
static void out_member(StringInfo buf, MultiXactMember *member)
Definition: mxactdesc.c:20
static char * buf
Definition: pg_test_fsync.c:67
void appendStringInfo(StringInfo str, const char *fmt,...)
Definition: stringinfo.c:91
MultiXactId mid
Definition: multixact.h:79
MultiXactMember members[FLEXIBLE_ARRAY_MEMBER]
Definition: multixact.h:82
MultiXactOffset moff
Definition: multixact.h:80
MultiXactId endTruncOff
Definition: multixact.h:93
MultiXactOffset startTruncMemb
Definition: multixact.h:96
MultiXactOffset endTruncMemb
Definition: multixact.h:97
MultiXactId startTruncOff
Definition: multixact.h:92
#define XLogRecGetInfo(decoder)
Definition: xlogreader.h:409
#define XLogRecGetData(decoder)
Definition: xlogreader.h:414
#define XLR_INFO_MASK
Definition: xlogrecord.h:62

References appendStringInfo(), buf, xl_multixact_truncate::endTruncMemb, xl_multixact_truncate::endTruncOff, i, xl_multixact_create::members, xl_multixact_create::mid, xl_multixact_create::moff, xl_multixact_create::nmembers, out_member(), xl_multixact_truncate::startTruncMemb, xl_multixact_truncate::startTruncOff, XLOG_MULTIXACT_CREATE_ID, XLOG_MULTIXACT_TRUNCATE_ID, XLOG_MULTIXACT_ZERO_MEM_PAGE, XLOG_MULTIXACT_ZERO_OFF_PAGE, XLogRecGetData, XLogRecGetInfo, and XLR_INFO_MASK.

◆ multixact_identify()

const char* multixact_identify ( uint8  info)

Definition at line 84 of file mxactdesc.c.

85 {
86  const char *id = NULL;
87 
88  switch (info & ~XLR_INFO_MASK)
89  {
91  id = "ZERO_OFF_PAGE";
92  break;
94  id = "ZERO_MEM_PAGE";
95  break;
97  id = "CREATE_ID";
98  break;
100  id = "TRUNCATE_ID";
101  break;
102  }
103 
104  return id;
105 }

References XLOG_MULTIXACT_CREATE_ID, XLOG_MULTIXACT_TRUNCATE_ID, XLOG_MULTIXACT_ZERO_MEM_PAGE, XLOG_MULTIXACT_ZERO_OFF_PAGE, and XLR_INFO_MASK.

◆ multixact_redo()

void multixact_redo ( XLogReaderState record)

Definition at line 3233 of file multixact.c.

3234 {
3235  uint8 info = XLogRecGetInfo(record) & ~XLR_INFO_MASK;
3236 
3237  /* Backup blocks are not used in multixact records */
3238  Assert(!XLogRecHasAnyBlockRefs(record));
3239 
3240  if (info == XLOG_MULTIXACT_ZERO_OFF_PAGE)
3241  {
3242  int pageno;
3243  int slotno;
3244 
3245  memcpy(&pageno, XLogRecGetData(record), sizeof(int));
3246 
3247  LWLockAcquire(MultiXactOffsetSLRULock, LW_EXCLUSIVE);
3248 
3249  slotno = ZeroMultiXactOffsetPage(pageno, false);
3251  Assert(!MultiXactOffsetCtl->shared->page_dirty[slotno]);
3252 
3253  LWLockRelease(MultiXactOffsetSLRULock);
3254  }
3255  else if (info == XLOG_MULTIXACT_ZERO_MEM_PAGE)
3256  {
3257  int pageno;
3258  int slotno;
3259 
3260  memcpy(&pageno, XLogRecGetData(record), sizeof(int));
3261 
3262  LWLockAcquire(MultiXactMemberSLRULock, LW_EXCLUSIVE);
3263 
3264  slotno = ZeroMultiXactMemberPage(pageno, false);
3266  Assert(!MultiXactMemberCtl->shared->page_dirty[slotno]);
3267 
3268  LWLockRelease(MultiXactMemberSLRULock);
3269  }
3270  else if (info == XLOG_MULTIXACT_CREATE_ID)
3271  {
3272  xl_multixact_create *xlrec =
3273  (xl_multixact_create *) XLogRecGetData(record);
3274  TransactionId max_xid;
3275  int i;
3276 
3277  /* Store the data back into the SLRU files */
3278  RecordNewMultiXact(xlrec->mid, xlrec->moff, xlrec->nmembers,
3279  xlrec->members);
3280 
3281  /* Make sure nextMXact/nextOffset are beyond what this record has */
3282  MultiXactAdvanceNextMXact(xlrec->mid + 1,
3283  xlrec->moff + xlrec->nmembers);
3284 
3285  /*
3286  * Make sure nextXid is beyond any XID mentioned in the record. This
3287  * should be unnecessary, since any XID found here ought to have other
3288  * evidence in the XLOG, but let's be safe.
3289  */
3290  max_xid = XLogRecGetXid(record);
3291  for (i = 0; i < xlrec->nmembers; i++)
3292  {
3293  if (TransactionIdPrecedes(max_xid, xlrec->members[i].xid))
3294  max_xid = xlrec->members[i].xid;
3295  }
3296 
3298  }
3299  else if (info == XLOG_MULTIXACT_TRUNCATE_ID)
3300  {
3301  xl_multixact_truncate xlrec;
3302  int pageno;
3303 
3304  memcpy(&xlrec, XLogRecGetData(record),
3306 
3307  elog(DEBUG1, "replaying multixact truncation: "
3308  "offsets [%u, %u), offsets segments [%x, %x), "
3309  "members [%u, %u), members segments [%x, %x)",
3310  xlrec.startTruncOff, xlrec.endTruncOff,
3313  xlrec.startTruncMemb, xlrec.endTruncMemb,
3316 
3317  /* should not be required, but more than cheap enough */
3318  LWLockAcquire(MultiXactTruncationLock, LW_EXCLUSIVE);
3319 
3320  /*
3321  * Advance the horizon values, so they're current at the end of
3322  * recovery.
3323  */
3324  SetMultiXactIdLimit(xlrec.endTruncOff, xlrec.oldestMultiDB, false);
3325 
3327 
3328  /*
3329  * During XLOG replay, latest_page_number isn't necessarily set up
3330  * yet; insert a suitable value to bypass the sanity test in
3331  * SimpleLruTruncate.
3332  */
3333  pageno = MultiXactIdToOffsetPage(xlrec.endTruncOff);
3334  MultiXactOffsetCtl->shared->latest_page_number = pageno;
3336 
3337  LWLockRelease(MultiXactTruncationLock);
3338  }
3339  else
3340  elog(PANIC, "multixact_redo: unknown op code %u", info);
3341 }
#define PANIC
Definition: elog.h:42
#define DEBUG1
Definition: elog.h:30
static void PerformOffsetsTruncation(MultiXactId oldestMulti, MultiXactId newOldestMulti)
Definition: multixact.c:2916
static void PerformMembersTruncation(MultiXactOffset oldestOffset, MultiXactOffset newOldestOffset)
Definition: multixact.c:2888
void SetMultiXactIdLimit(MultiXactId oldest_datminmxid, Oid oldest_datoid, bool is_startup)
Definition: multixact.c:2213
static void RecordNewMultiXact(MultiXactId multi, MultiXactOffset offset, int nmembers, MultiXactMember *members)
Definition: multixact.c:864
#define MXOffsetToMemberSegment(xid)
Definition: multixact.c:160
void MultiXactAdvanceNextMXact(MultiXactId minMulti, MultiXactOffset minMultiOffset)
Definition: multixact.c:2362
#define MultiXactIdToOffsetSegment(xid)
Definition: multixact.c:115
#define SizeOfMultiXactTruncate
Definition: multixact.h:100
bool TransactionIdPrecedes(TransactionId id1, TransactionId id2)
Definition: transam.c:280
void AdvanceNextFullTransactionIdPastXid(TransactionId xid)
Definition: varsup.c:277
#define XLogRecGetXid(decoder)
Definition: xlogreader.h:411
#define XLogRecHasAnyBlockRefs(decoder)
Definition: xlogreader.h:416

References AdvanceNextFullTransactionIdPastXid(), Assert(), DEBUG1, elog(), xl_multixact_truncate::endTruncMemb, xl_multixact_truncate::endTruncOff, i, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), xl_multixact_create::members, xl_multixact_create::mid, xl_multixact_create::moff, MultiXactAdvanceNextMXact(), MultiXactIdToOffsetPage, MultiXactIdToOffsetSegment, MultiXactMemberCtl, MultiXactOffsetCtl, MXOffsetToMemberSegment, xl_multixact_create::nmembers, xl_multixact_truncate::oldestMultiDB, PANIC, PerformMembersTruncation(), PerformOffsetsTruncation(), RecordNewMultiXact(), SetMultiXactIdLimit(), SimpleLruWritePage(), SizeOfMultiXactTruncate, xl_multixact_truncate::startTruncMemb, xl_multixact_truncate::startTruncOff, TransactionIdPrecedes(), MultiXactMember::xid, XLOG_MULTIXACT_CREATE_ID, XLOG_MULTIXACT_TRUNCATE_ID, XLOG_MULTIXACT_ZERO_MEM_PAGE, XLOG_MULTIXACT_ZERO_OFF_PAGE, XLogRecGetData, XLogRecGetInfo, XLogRecGetXid, XLogRecHasAnyBlockRefs, XLR_INFO_MASK, ZeroMultiXactMemberPage(), and ZeroMultiXactOffsetPage().

◆ multixact_twophase_postabort()

void multixact_twophase_postabort ( TransactionId  xid,
uint16  info,
void *  recdata,
uint32  len 
)

Definition at line 1815 of file multixact.c.

1817 {
1818  multixact_twophase_postcommit(xid, info, recdata, len);
1819 }
void multixact_twophase_postcommit(TransactionId xid, uint16 info, void *recdata, uint32 len)
Definition: multixact.c:1800
const void size_t len

References len, and multixact_twophase_postcommit().

◆ multixact_twophase_postcommit()

void multixact_twophase_postcommit ( TransactionId  xid,
uint16  info,
void *  recdata,
uint32  len 
)

Definition at line 1800 of file multixact.c.

1802 {
1803  BackendId dummyBackendId = TwoPhaseGetDummyBackendId(xid, true);
1804 
1805  Assert(len == sizeof(MultiXactId));
1806 
1807  OldestMemberMXactId[dummyBackendId] = InvalidMultiXactId;
1808 }
int BackendId
Definition: backendid.h:21
BackendId TwoPhaseGetDummyBackendId(TransactionId xid, bool lock_held)
Definition: twophase.c:918

References Assert(), InvalidMultiXactId, len, OldestMemberMXactId, and TwoPhaseGetDummyBackendId().

Referenced by multixact_twophase_postabort().

◆ multixact_twophase_recover()

void multixact_twophase_recover ( TransactionId  xid,
uint16  info,
void *  recdata,
uint32  len 
)

Definition at line 1779 of file multixact.c.

1781 {
1782  BackendId dummyBackendId = TwoPhaseGetDummyBackendId(xid, false);
1783  MultiXactId oldestMember;
1784 
1785  /*
1786  * Get the oldest member XID from the state file record, and set it in the
1787  * OldestMemberMXactId slot reserved for this prepared transaction.
1788  */
1789  Assert(len == sizeof(MultiXactId));
1790  oldestMember = *((MultiXactId *) recdata);
1791 
1792  OldestMemberMXactId[dummyBackendId] = oldestMember;
1793 }

References Assert(), len, OldestMemberMXactId, and TwoPhaseGetDummyBackendId().

◆ MultiXactAdvanceNextMXact()

void MultiXactAdvanceNextMXact ( MultiXactId  minMulti,
MultiXactOffset  minMultiOffset 
)

Definition at line 2362 of file multixact.c.

2364 {
2365  LWLockAcquire(MultiXactGenLock, LW_EXCLUSIVE);
2367  {
2368  debug_elog3(DEBUG2, "MultiXact: setting next multi to %u", minMulti);
2369  MultiXactState->nextMXact = minMulti;
2370  }
2371  if (MultiXactOffsetPrecedes(MultiXactState->nextOffset, minMultiOffset))
2372  {
2373  debug_elog3(DEBUG2, "MultiXact: setting next offset to %u",
2374  minMultiOffset);
2375  MultiXactState->nextOffset = minMultiOffset;
2376  }
2377  LWLockRelease(MultiXactGenLock);
2378 }
static bool MultiXactOffsetPrecedes(MultiXactOffset offset1, MultiXactOffset offset2)
Definition: multixact.c:3182

References DEBUG2, debug_elog3, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MultiXactIdPrecedes(), MultiXactOffsetPrecedes(), MultiXactState, MultiXactStateData::nextMXact, and MultiXactStateData::nextOffset.

Referenced by multixact_redo(), and xlog_redo().

◆ MultiXactAdvanceOldest()

void MultiXactAdvanceOldest ( MultiXactId  oldestMulti,
Oid  oldestMultiDB 
)

Definition at line 2387 of file multixact.c.

2388 {
2389  Assert(InRecovery);
2390 
2392  SetMultiXactIdLimit(oldestMulti, oldestMultiDB, false);
2393 }
bool InRecovery
Definition: xlogutils.c:53

References Assert(), InRecovery, MultiXactIdPrecedes(), MultiXactState, MultiXactStateData::oldestMultiXactId, and SetMultiXactIdLimit().

Referenced by xlog_redo().

◆ MultiXactGetCheckptMulti()

void MultiXactGetCheckptMulti ( bool  is_shutdown,
MultiXactId nextMulti,
MultiXactOffset nextMultiOffset,
MultiXactId oldestMulti,
Oid oldestMultiDB 
)

Definition at line 2133 of file multixact.c.

2138 {
2139  LWLockAcquire(MultiXactGenLock, LW_SHARED);
2140  *nextMulti = MultiXactState->nextMXact;
2141  *nextMultiOffset = MultiXactState->nextOffset;
2142  *oldestMulti = MultiXactState->oldestMultiXactId;
2143  *oldestMultiDB = MultiXactState->oldestMultiXactDB;
2144  LWLockRelease(MultiXactGenLock);
2145 
2147  "MultiXact: checkpoint is nextMulti %u, nextOffset %u, oldestMulti %u in DB %u",
2148  *nextMulti, *nextMultiOffset, *oldestMulti, *oldestMultiDB);
2149 }
#define debug_elog6(a, b, c, d, e, f)
Definition: multixact.c:338

References DEBUG2, debug_elog6, LW_SHARED, LWLockAcquire(), LWLockRelease(), MultiXactState, MultiXactStateData::nextMXact, MultiXactStateData::nextOffset, MultiXactStateData::oldestMultiXactDB, and MultiXactStateData::oldestMultiXactId.

Referenced by CreateCheckPoint().

◆ MultiXactIdCreate()

MultiXactId MultiXactIdCreate ( TransactionId  xid1,
MultiXactStatus  status1,
TransactionId  xid2,
MultiXactStatus  status2 
)

Definition at line 387 of file multixact.c.

389 {
390  MultiXactId newMulti;
391  MultiXactMember members[2];
392 
395 
396  Assert(!TransactionIdEquals(xid1, xid2) || (status1 != status2));
397 
398  /* MultiXactIdSetOldestMember() must have been called already. */
400 
401  /*
402  * Note: unlike MultiXactIdExpand, we don't bother to check that both XIDs
403  * are still running. In typical usage, xid2 will be our own XID and the
404  * caller just did a check on xid1, so it'd be wasted effort.
405  */
406 
407  members[0].xid = xid1;
408  members[0].status = status1;
409  members[1].xid = xid2;
410  members[1].status = status2;
411 
412  newMulti = MultiXactIdCreateFromMembers(2, members);
413 
414  debug_elog3(DEBUG2, "Create: %s",
415  mxid_to_string(newMulti, 2, members));
416 
417  return newMulti;
418 }
MultiXactId MultiXactIdCreateFromMembers(int nmembers, MultiXactMember *members)
Definition: multixact.c:768
#define TransactionIdEquals(id1, id2)
Definition: transam.h:43

References Assert(), DEBUG2, debug_elog3, MultiXactIdCreateFromMembers(), MultiXactIdIsValid, mxid_to_string(), MyBackendId, OldestMemberMXactId, MultiXactMember::status, TransactionIdEquals, TransactionIdIsValid, and MultiXactMember::xid.

Referenced by compute_new_xmax_infomask().

◆ MultiXactIdCreateFromMembers()

MultiXactId MultiXactIdCreateFromMembers ( int  nmembers,
MultiXactMember members 
)

Definition at line 768 of file multixact.c.

769 {
770  MultiXactId multi;
771  MultiXactOffset offset;
772  xl_multixact_create xlrec;
773 
774  debug_elog3(DEBUG2, "Create: %s",
775  mxid_to_string(InvalidMultiXactId, nmembers, members));
776 
777  /*
778  * See if the same set of members already exists in our cache; if so, just
779  * re-use that MultiXactId. (Note: it might seem that looking in our
780  * cache is insufficient, and we ought to search disk to see if a
781  * duplicate definition already exists. But since we only ever create
782  * MultiXacts containing our own XID, in most cases any such MultiXacts
783  * were in fact created by us, and so will be in our cache. There are
784  * corner cases where someone else added us to a MultiXact without our
785  * knowledge, but it's not worth checking for.)
786  */
787  multi = mXactCacheGetBySet(nmembers, members);
788  if (MultiXactIdIsValid(multi))
789  {
790  debug_elog2(DEBUG2, "Create: in cache!");
791  return multi;
792  }
793 
794  /* Verify that there is a single update Xid among the given members. */
795  {
796  int i;
797  bool has_update = false;
798 
799  for (i = 0; i < nmembers; i++)
800  {
801  if (ISUPDATE_from_mxstatus(members[i].status))
802  {
803  if (has_update)
804  elog(ERROR, "new multixact has more than one updating member: %s",
805  mxid_to_string(InvalidMultiXactId, nmembers, members));
806  has_update = true;
807  }
808  }
809  }
810 
811  /*
812  * Assign the MXID and offsets range to use, and make sure there is space
813  * in the OFFSETs and MEMBERs files. NB: this routine does
814  * START_CRIT_SECTION().
815  *
816  * Note: unlike MultiXactIdCreate and MultiXactIdExpand, we do not check
817  * that we've called MultiXactIdSetOldestMember here. This is because
818  * this routine is used in some places to create new MultiXactIds of which
819  * the current backend is not a member, notably during freezing of multis
820  * in vacuum. During vacuum, in particular, it would be unacceptable to
821  * keep OldestMulti set, in case it runs for long.
822  */
823  multi = GetNewMultiXactId(nmembers, &offset);
824 
825  /* Make an XLOG entry describing the new MXID. */
826  xlrec.mid = multi;
827  xlrec.moff = offset;
828  xlrec.nmembers = nmembers;
829 
830  /*
831  * XXX Note: there's a lot of padding space in MultiXactMember. We could
832  * find a more compact representation of this Xlog record -- perhaps all
833  * the status flags in one XLogRecData, then all the xids in another one?
834  * Not clear that it's worth the trouble though.
835  */
836  XLogBeginInsert();
837  XLogRegisterData((char *) (&xlrec), SizeOfMultiXactCreate);
838  XLogRegisterData((char *) members, nmembers * sizeof(MultiXactMember));
839 
840  (void) XLogInsert(RM_MULTIXACT_ID, XLOG_MULTIXACT_CREATE_ID);
841 
842  /* Now enter the information into the OFFSETs and MEMBERs logs */
843  RecordNewMultiXact(multi, offset, nmembers, members);
844 
845  /* Done with critical section */
847 
848  /* Store the new MultiXactId in the local cache, too */
849  mXactCachePut(multi, nmembers, members);
850 
851  debug_elog2(DEBUG2, "Create: all done");
852 
853  return multi;
854 }
#define END_CRIT_SECTION()
Definition: miscadmin.h:150
static MultiXactId GetNewMultiXactId(int nmembers, MultiXactOffset *offset)
Definition: multixact.c:958
static MultiXactId mXactCacheGetBySet(int nmembers, MultiXactMember *members)
Definition: multixact.c:1499
#define ISUPDATE_from_mxstatus(status)
Definition: multixact.h:56
#define SizeOfMultiXactCreate
Definition: multixact.h:85
static void static void status(const char *fmt,...) pg_attribute_printf(1
Definition: pg_regress.c:224
void XLogRegisterData(char *data, uint32 len)
Definition: xloginsert.c:351
XLogRecPtr XLogInsert(RmgrId rmid, uint8 info)
Definition: xloginsert.c:451
void XLogBeginInsert(void)
Definition: xloginsert.c:150

References DEBUG2, debug_elog2, debug_elog3, elog(), END_CRIT_SECTION, ERROR, GetNewMultiXactId(), i, InvalidMultiXactId, ISUPDATE_from_mxstatus, xl_multixact_create::mid, xl_multixact_create::moff, MultiXactIdIsValid, mXactCacheGetBySet(), mXactCachePut(), mxid_to_string(), xl_multixact_create::nmembers, RecordNewMultiXact(), SizeOfMultiXactCreate, status(), XLOG_MULTIXACT_CREATE_ID, XLogBeginInsert(), XLogInsert(), and XLogRegisterData().

Referenced by FreezeMultiXactId(), MultiXactIdCreate(), and MultiXactIdExpand().

◆ MultiXactIdExpand()

MultiXactId MultiXactIdExpand ( MultiXactId  multi,
TransactionId  xid,
MultiXactStatus  status 
)

Definition at line 440 of file multixact.c.

441 {
442  MultiXactId newMulti;
443  MultiXactMember *members;
444  MultiXactMember *newMembers;
445  int nmembers;
446  int i;
447  int j;
448 
449  Assert(MultiXactIdIsValid(multi));
451 
452  /* MultiXactIdSetOldestMember() must have been called already. */
454 
455  debug_elog5(DEBUG2, "Expand: received multi %u, xid %u status %s",
456  multi, xid, mxstatus_to_string(status));
457 
458  /*
459  * Note: we don't allow for old multis here. The reason is that the only
460  * caller of this function does a check that the multixact is no longer
461  * running.
462  */
463  nmembers = GetMultiXactIdMembers(multi, &members, false, false);
464 
465  if (nmembers < 0)
466  {
467  MultiXactMember member;
468 
469  /*
470  * The MultiXactId is obsolete. This can only happen if all the
471  * MultiXactId members stop running between the caller checking and
472  * passing it to us. It would be better to return that fact to the
473  * caller, but it would complicate the API and it's unlikely to happen
474  * too often, so just deal with it by creating a singleton MultiXact.
475  */
476  member.xid = xid;
477  member.status = status;
478  newMulti = MultiXactIdCreateFromMembers(1, &member);
479 
480  debug_elog4(DEBUG2, "Expand: %u has no members, create singleton %u",
481  multi, newMulti);
482  return newMulti;
483  }
484 
485  /*
486  * If the TransactionId is already a member of the MultiXactId with the
487  * same status, just return the existing MultiXactId.
488  */
489  for (i = 0; i < nmembers; i++)
490  {
491  if (TransactionIdEquals(members[i].xid, xid) &&
492  (members[i].status == status))
493  {
494  debug_elog4(DEBUG2, "Expand: %u is already a member of %u",
495  xid, multi);
496  pfree(members);
497  return multi;
498  }
499  }
500 
501  /*
502  * Determine which of the members of the MultiXactId are still of
503  * interest. This is any running transaction, and also any transaction
504  * that grabbed something stronger than just a lock and was committed. (An
505  * update that aborted is of no interest here; and having more than one
506  * update Xid in a multixact would cause errors elsewhere.)
507  *
508  * Removing dead members is not just an optimization: freezing of tuples
509  * whose Xmax are multis depends on this behavior.
510  *
511  * Note we have the same race condition here as above: j could be 0 at the
512  * end of the loop.
513  */
514  newMembers = (MultiXactMember *)
515  palloc(sizeof(MultiXactMember) * (nmembers + 1));
516 
517  for (i = 0, j = 0; i < nmembers; i++)
518  {
519  if (TransactionIdIsInProgress(members[i].xid) ||
520  (ISUPDATE_from_mxstatus(members[i].status) &&
521  TransactionIdDidCommit(members[i].xid)))
522  {
523  newMembers[j].xid = members[i].xid;
524  newMembers[j++].status = members[i].status;
525  }
526  }
527 
528  newMembers[j].xid = xid;
529  newMembers[j++].status = status;
530  newMulti = MultiXactIdCreateFromMembers(j, newMembers);
531 
532  pfree(members);
533  pfree(newMembers);
534 
535  debug_elog3(DEBUG2, "Expand: returning new multi %u", newMulti);
536 
537  return newMulti;
538 }
int j
Definition: isn.c:74
void pfree(void *pointer)
Definition: mcxt.c:1436
#define debug_elog5(a, b, c, d, e)
Definition: multixact.c:337
#define debug_elog4(a, b, c, d)
Definition: multixact.c:336
static char * mxstatus_to_string(MultiXactStatus status)
Definition: multixact.c:1634
int GetMultiXactIdMembers(MultiXactId multi, MultiXactMember **members, bool from_pgupgrade, bool isLockOnly)
Definition: multixact.c:1225
bool TransactionIdIsInProgress(TransactionId xid)
Definition: procarray.c:1386
bool TransactionIdDidCommit(TransactionId transactionId)
Definition: transam.c:126

References Assert(), DEBUG2, debug_elog3, debug_elog4, debug_elog5, GetMultiXactIdMembers(), i, ISUPDATE_from_mxstatus, j, MultiXactIdCreateFromMembers(), MultiXactIdIsValid, mxstatus_to_string(), MyBackendId, OldestMemberMXactId, palloc(), pfree(), MultiXactMember::status, status(), TransactionIdDidCommit(), TransactionIdEquals, TransactionIdIsInProgress(), TransactionIdIsValid, and MultiXactMember::xid.

Referenced by compute_new_xmax_infomask().

◆ MultiXactIdIsRunning()

bool MultiXactIdIsRunning ( MultiXactId  multi,
bool  isLockOnly 
)

Definition at line 552 of file multixact.c.

553 {
554  MultiXactMember *members;
555  int nmembers;
556  int i;
557 
558  debug_elog3(DEBUG2, "IsRunning %u?", multi);
559 
560  /*
561  * "false" here means we assume our callers have checked that the given
562  * multi cannot possibly come from a pg_upgraded database.
563  */
564  nmembers = GetMultiXactIdMembers(multi, &members, false, isLockOnly);
565 
566  if (nmembers <= 0)
567  {
568  debug_elog2(DEBUG2, "IsRunning: no members");
569  return false;
570  }
571 
572  /*
573  * Checking for myself is cheap compared to looking in shared memory;
574  * return true if any live subtransaction of the current top-level
575  * transaction is a member.
576  *
577  * This is not needed for correctness, it's just a fast path.
578  */
579  for (i = 0; i < nmembers; i++)
580  {
581  if (TransactionIdIsCurrentTransactionId(members[i].xid))
582  {
583  debug_elog3(DEBUG2, "IsRunning: I (%d) am running!", i);
584  pfree(members);
585  return true;
586  }
587  }
588 
589  /*
590  * This could be made faster by having another entry point in procarray.c,
591  * walking the PGPROC array only once for all the members. But in most
592  * cases nmembers should be small enough that it doesn't much matter.
593  */
594  for (i = 0; i < nmembers; i++)
595  {
596  if (TransactionIdIsInProgress(members[i].xid))
597  {
598  debug_elog4(DEBUG2, "IsRunning: member %d (%u) is running",
599  i, members[i].xid);
600  pfree(members);
601  return true;
602  }
603  }
604 
605  pfree(members);
606 
607  debug_elog3(DEBUG2, "IsRunning: %u is not running", multi);
608 
609  return false;
610 }
bool TransactionIdIsCurrentTransactionId(TransactionId xid)
Definition: xact.c:926

References DEBUG2, debug_elog2, debug_elog3, debug_elog4, GetMultiXactIdMembers(), i, pfree(), TransactionIdIsCurrentTransactionId(), and TransactionIdIsInProgress().

Referenced by compute_new_xmax_infomask(), FreezeMultiXactId(), HeapTupleSatisfiesUpdate(), and HeapTupleSatisfiesVacuumHorizon().

◆ MultiXactIdPrecedes()

◆ MultiXactIdPrecedesOrEquals()

bool MultiXactIdPrecedesOrEquals ( MultiXactId  multi1,
MultiXactId  multi2 
)

Definition at line 3170 of file multixact.c.

3171 {
3172  int32 diff = (int32) (multi1 - multi2);
3173 
3174  return (diff <= 0);
3175 }

Referenced by check_mxid_in_range(), heap_tuple_should_freeze(), heap_vacuum_rel(), TruncateMultiXact(), and vacuum_get_cutoffs().

◆ MultiXactIdSetOldestMember()

void MultiXactIdSetOldestMember ( void  )

Definition at line 626 of file multixact.c.

627 {
629  {
630  MultiXactId nextMXact;
631 
632  /*
633  * You might think we don't need to acquire a lock here, since
634  * fetching and storing of TransactionIds is probably atomic, but in
635  * fact we do: suppose we pick up nextMXact and then lose the CPU for
636  * a long time. Someone else could advance nextMXact, and then
637  * another someone else could compute an OldestVisibleMXactId that
638  * would be after the value we are going to store when we get control
639  * back. Which would be wrong.
640  *
641  * Note that a shared lock is sufficient, because it's enough to stop
642  * someone from advancing nextMXact; and nobody else could be trying
643  * to write to our OldestMember entry, only reading (and we assume
644  * storing it is atomic.)
645  */
646  LWLockAcquire(MultiXactGenLock, LW_SHARED);
647 
648  /*
649  * We have to beware of the possibility that nextMXact is in the
650  * wrapped-around state. We don't fix the counter itself here, but we
651  * must be sure to store a valid value in our array entry.
652  */
653  nextMXact = MultiXactState->nextMXact;
654  if (nextMXact < FirstMultiXactId)
655  nextMXact = FirstMultiXactId;
656 
657  OldestMemberMXactId[MyBackendId] = nextMXact;
658 
659  LWLockRelease(MultiXactGenLock);
660 
661  debug_elog4(DEBUG2, "MultiXact: setting OldestMember[%d] = %u",
662  MyBackendId, nextMXact);
663  }
664 }

References DEBUG2, debug_elog4, FirstMultiXactId, LW_SHARED, LWLockAcquire(), LWLockRelease(), MultiXactIdIsValid, MultiXactState, MyBackendId, MultiXactStateData::nextMXact, and OldestMemberMXactId.

Referenced by heap_delete(), heap_lock_tuple(), heap_lock_updated_tuple(), and heap_update().

◆ MultiXactMemberFreezeThreshold()

int MultiXactMemberFreezeThreshold ( void  )

Definition at line 2825 of file multixact.c.

2826 {
2827  MultiXactOffset members;
2828  uint32 multixacts;
2829  uint32 victim_multixacts;
2830  double fraction;
2831 
2832  /* If we can't determine member space utilization, assume the worst. */
2833  if (!ReadMultiXactCounts(&multixacts, &members))
2834  return 0;
2835 
2836  /* If member space utilization is low, no special action is required. */
2837  if (members <= MULTIXACT_MEMBER_SAFE_THRESHOLD)
2839 
2840  /*
2841  * Compute a target for relminmxid advancement. The number of multixacts
2842  * we try to eliminate from the system is based on how far we are past
2843  * MULTIXACT_MEMBER_SAFE_THRESHOLD.
2844  */
2845  fraction = (double) (members - MULTIXACT_MEMBER_SAFE_THRESHOLD) /
2847  victim_multixacts = multixacts * fraction;
2848 
2849  /* fraction could be > 1.0, but lowest possible freeze age is zero */
2850  if (victim_multixacts > multixacts)
2851  return 0;
2852  return multixacts - victim_multixacts;
2853 }
int autovacuum_multixact_freeze_max_age
Definition: autovacuum.c:127
#define MULTIXACT_MEMBER_SAFE_THRESHOLD
Definition: multixact.c:177
static bool ReadMultiXactCounts(uint32 *multixacts, MultiXactOffset *members)
Definition: multixact.c:2773
#define MULTIXACT_MEMBER_DANGER_THRESHOLD
Definition: multixact.c:178

References autovacuum_multixact_freeze_max_age, MULTIXACT_MEMBER_DANGER_THRESHOLD, MULTIXACT_MEMBER_SAFE_THRESHOLD, and ReadMultiXactCounts().

Referenced by do_autovacuum(), do_start_worker(), and vacuum_get_cutoffs().

◆ multixactmemberssyncfiletag()

int multixactmemberssyncfiletag ( const FileTag ftag,
char *  path 
)

Definition at line 3418 of file multixact.c.

3419 {
3420  return SlruSyncFileTag(MultiXactMemberCtl, ftag, path);
3421 }
int SlruSyncFileTag(SlruCtl ctl, const FileTag *ftag, char *path)
Definition: slru.c:1594

References MultiXactMemberCtl, and SlruSyncFileTag().

◆ multixactoffsetssyncfiletag()

int multixactoffsetssyncfiletag ( const FileTag ftag,
char *  path 
)

Definition at line 3409 of file multixact.c.

3410 {
3411  return SlruSyncFileTag(MultiXactOffsetCtl, ftag, path);
3412 }

References MultiXactOffsetCtl, and SlruSyncFileTag().

◆ MultiXactSetNextMXact()

void MultiXactSetNextMXact ( MultiXactId  nextMulti,
MultiXactOffset  nextMultiOffset 
)

Definition at line 2179 of file multixact.c.

2181 {
2182  debug_elog4(DEBUG2, "MultiXact: setting next multi to %u offset %u",
2183  nextMulti, nextMultiOffset);
2184  LWLockAcquire(MultiXactGenLock, LW_EXCLUSIVE);
2185  MultiXactState->nextMXact = nextMulti;
2186  MultiXactState->nextOffset = nextMultiOffset;
2187  LWLockRelease(MultiXactGenLock);
2188 
2189  /*
2190  * During a binary upgrade, make sure that the offsets SLRU is large
2191  * enough to contain the next value that would be created.
2192  *
2193  * We need to do this pretty early during the first startup in binary
2194  * upgrade mode: before StartupMultiXact() in fact, because this routine
2195  * is called even before that by StartupXLOG(). And we can't do it
2196  * earlier than at this point, because during that first call of this
2197  * routine we determine the MultiXactState->nextMXact value that
2198  * MaybeExtendOffsetSlru needs.
2199  */
2200  if (IsBinaryUpgrade)
2202 }
bool IsBinaryUpgrade
Definition: globals.c:114
static void MaybeExtendOffsetSlru(void)
Definition: multixact.c:1975

References DEBUG2, debug_elog4, IsBinaryUpgrade, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MaybeExtendOffsetSlru(), MultiXactState, MultiXactStateData::nextMXact, and MultiXactStateData::nextOffset.

Referenced by BootStrapXLOG(), StartupXLOG(), and xlog_redo().

◆ MultiXactShmemInit()

void MultiXactShmemInit ( void  )

Definition at line 1844 of file multixact.c.

1845 {
1846  bool found;
1847 
1848  debug_elog2(DEBUG2, "Shared Memory Init for MultiXact");
1849 
1852 
1854  "MultiXactOffset", NUM_MULTIXACTOFFSET_BUFFERS, 0,
1855  MultiXactOffsetSLRULock, "pg_multixact/offsets",
1860  "MultiXactMember", NUM_MULTIXACTMEMBER_BUFFERS, 0,
1861  MultiXactMemberSLRULock, "pg_multixact/members",
1864  /* doesn't call SimpleLruTruncate() or meet criteria for unit tests */
1865 
1866  /* Initialize our shared state struct */
1867  MultiXactState = ShmemInitStruct("Shared MultiXact State",
1869  &found);
1870  if (!IsUnderPostmaster)
1871  {
1872  Assert(!found);
1873 
1874  /* Make sure we zero out the per-backend state */
1876  }
1877  else
1878  Assert(found);
1879 
1880  /*
1881  * Set up array pointers. Note that perBackendXactIds[0] is wasted space
1882  * since we only use indexes 1..MaxOldestSlot in each array.
1883  */
1886 }
#define MemSet(start, val, len)
Definition: c.h:1004
bool IsUnderPostmaster
Definition: globals.c:113
@ LWTRANCHE_MULTIXACTMEMBER_BUFFER
Definition: lwlock.h:184
@ LWTRANCHE_MULTIXACTOFFSET_BUFFER
Definition: lwlock.h:183
#define MULTIXACT_OFFSETS_PER_PAGE
Definition: multixact.c:109
static bool MultiXactOffsetPagePrecedes(int page1, int page2)
Definition: multixact.c:3116
#define SHARED_MULTIXACT_STATE_SIZE
static bool MultiXactMemberPagePrecedes(int page1, int page2)
Definition: multixact.c:3136
#define NUM_MULTIXACTOFFSET_BUFFERS
Definition: multixact.h:33
#define NUM_MULTIXACTMEMBER_BUFFERS
Definition: multixact.h:34
void * ShmemInitStruct(const char *name, Size size, bool *foundPtr)
Definition: shmem.c:396
void SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns, LWLock *ctllock, const char *subdir, int tranche_id, SyncRequestHandler sync_handler)
Definition: slru.c:188
#define SlruPagePrecedesUnitTests(ctl, per_page)
Definition: slru.h:156
MultiXactId perBackendXactIds[FLEXIBLE_ARRAY_MEMBER]
Definition: multixact.c:283
@ SYNC_HANDLER_MULTIXACT_MEMBER
Definition: sync.h:41
@ SYNC_HANDLER_MULTIXACT_OFFSET
Definition: sync.h:40

References Assert(), DEBUG2, debug_elog2, IsUnderPostmaster, LWTRANCHE_MULTIXACTMEMBER_BUFFER, LWTRANCHE_MULTIXACTOFFSET_BUFFER, MaxOldestSlot, MemSet, MULTIXACT_OFFSETS_PER_PAGE, MultiXactMemberCtl, MultiXactMemberPagePrecedes(), MultiXactOffsetCtl, MultiXactOffsetPagePrecedes(), MultiXactState, NUM_MULTIXACTMEMBER_BUFFERS, NUM_MULTIXACTOFFSET_BUFFERS, OldestMemberMXactId, OldestVisibleMXactId, MultiXactStateData::perBackendXactIds, SHARED_MULTIXACT_STATE_SIZE, ShmemInitStruct(), SimpleLruInit(), SlruPagePrecedesUnitTests, SYNC_HANDLER_MULTIXACT_MEMBER, and SYNC_HANDLER_MULTIXACT_OFFSET.

Referenced by CreateSharedMemoryAndSemaphores().

◆ MultiXactShmemSize()

Size MultiXactShmemSize ( void  )

Definition at line 1827 of file multixact.c.

1828 {
1829  Size size;
1830 
1831  /* We need 2*MaxOldestSlot + 1 perBackendXactIds[] entries */
1832 #define SHARED_MULTIXACT_STATE_SIZE \
1833  add_size(offsetof(MultiXactStateData, perBackendXactIds) + sizeof(MultiXactId), \
1834  mul_size(sizeof(MultiXactId) * 2, MaxOldestSlot))
1835 
1839 
1840  return size;
1841 }
size_t Size
Definition: c.h:589
Size add_size(Size s1, Size s2)
Definition: shmem.c:502
Size SimpleLruShmemSize(int nslots, int nlsns)
Definition: slru.c:156

References add_size(), NUM_MULTIXACTMEMBER_BUFFERS, NUM_MULTIXACTOFFSET_BUFFERS, SHARED_MULTIXACT_STATE_SIZE, and SimpleLruShmemSize().

Referenced by CalculateShmemSize().

◆ mxid_to_string()

char* mxid_to_string ( MultiXactId  multi,
int  nmembers,
MultiXactMember members 
)

Definition at line 1657 of file multixact.c.

1658 {
1659  static char *str = NULL;
1661  int i;
1662 
1663  if (str != NULL)
1664  pfree(str);
1665 
1666  initStringInfo(&buf);
1667 
1668  appendStringInfo(&buf, "%u %d[%u (%s)", multi, nmembers, members[0].xid,
1669  mxstatus_to_string(members[0].status));
1670 
1671  for (i = 1; i < nmembers; i++)
1672  appendStringInfo(&buf, ", %u (%s)", members[i].xid,
1673  mxstatus_to_string(members[i].status));
1674 
1675  appendStringInfoChar(&buf, ']');
1677  pfree(buf.data);
1678  return str;
1679 }
MemoryContext TopMemoryContext
Definition: mcxt.c:141
char * MemoryContextStrdup(MemoryContext context, const char *string)
Definition: mcxt.c:1611
void appendStringInfoChar(StringInfo str, char ch)
Definition: stringinfo.c:188
void initStringInfo(StringInfo str)
Definition: stringinfo.c:59

References appendStringInfo(), appendStringInfoChar(), buf, i, initStringInfo(), MemoryContextStrdup(), mxstatus_to_string(), pfree(), status(), generate_unaccent_rules::str, and TopMemoryContext.

Referenced by GetMultiXactIdMembers(), MultiXactIdCreate(), MultiXactIdCreateFromMembers(), mXactCacheGetById(), mXactCacheGetBySet(), and mXactCachePut().

◆ PostPrepare_MultiXact()

void PostPrepare_MultiXact ( TransactionId  xid)

Definition at line 1730 of file multixact.c.

1731 {
1732  MultiXactId myOldestMember;
1733 
1734  /*
1735  * Transfer our OldestMemberMXactId value to the slot reserved for the
1736  * prepared transaction.
1737  */
1738  myOldestMember = OldestMemberMXactId[MyBackendId];
1739  if (MultiXactIdIsValid(myOldestMember))
1740  {
1741  BackendId dummyBackendId = TwoPhaseGetDummyBackendId(xid, false);
1742 
1743  /*
1744  * Even though storing MultiXactId is atomic, acquire lock to make
1745  * sure others see both changes, not just the reset of the slot of the
1746  * current backend. Using a volatile pointer might suffice, but this
1747  * isn't a hot spot.
1748  */
1749  LWLockAcquire(MultiXactGenLock, LW_EXCLUSIVE);
1750 
1751  OldestMemberMXactId[dummyBackendId] = myOldestMember;
1753 
1754  LWLockRelease(MultiXactGenLock);
1755  }
1756 
1757  /*
1758  * We don't need to transfer OldestVisibleMXactId value, because the
1759  * transaction is not going to be looking at any more multixacts once it's
1760  * prepared.
1761  *
1762  * We assume that storing a MultiXactId is atomic and so we need not take
1763  * MultiXactGenLock to do this.
1764  */
1766 
1767  /*
1768  * Discard the local MultiXactId cache like in AtEOXact_MultiXact.
1769  */
1770  MXactContext = NULL;
1772 }

References dclist_init(), InvalidMultiXactId, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MultiXactIdIsValid, MXactCache, MXactContext, MyBackendId, OldestMemberMXactId, OldestVisibleMXactId, and TwoPhaseGetDummyBackendId().

Referenced by PrepareTransaction().

◆ ReadMultiXactIdRange()

void ReadMultiXactIdRange ( MultiXactId oldest,
MultiXactId next 
)

Definition at line 744 of file multixact.c.

745 {
746  LWLockAcquire(MultiXactGenLock, LW_SHARED);
749  LWLockRelease(MultiXactGenLock);
750 
751  if (*oldest < FirstMultiXactId)
752  *oldest = FirstMultiXactId;
753  if (*next < FirstMultiXactId)
755 }
static int32 next
Definition: blutils.c:219

References FirstMultiXactId, LW_SHARED, LWLockAcquire(), LWLockRelease(), MultiXactState, next, MultiXactStateData::nextMXact, and MultiXactStateData::oldestMultiXactId.

Referenced by update_cached_mxid_range().

◆ ReadNextMultiXactId()

MultiXactId ReadNextMultiXactId ( void  )

Definition at line 724 of file multixact.c.

725 {
726  MultiXactId mxid;
727 
728  /* XXX we could presumably do this without a lock. */
729  LWLockAcquire(MultiXactGenLock, LW_SHARED);
730  mxid = MultiXactState->nextMXact;
731  LWLockRelease(MultiXactGenLock);
732 
733  if (mxid < FirstMultiXactId)
734  mxid = FirstMultiXactId;
735 
736  return mxid;
737 }

References FirstMultiXactId, LW_SHARED, LWLockAcquire(), LWLockRelease(), MultiXactState, and MultiXactStateData::nextMXact.

Referenced by ATRewriteTables(), AutoVacWorkerMain(), do_start_worker(), mxid_age(), refresh_by_heap_swap(), vac_update_datfrozenxid(), vac_update_relstats(), vacuum_get_cutoffs(), and vacuum_xid_failsafe_check().

◆ SetMultiXactIdLimit()

void SetMultiXactIdLimit ( MultiXactId  oldest_datminmxid,
Oid  oldest_datoid,
bool  is_startup 
)

Definition at line 2213 of file multixact.c.

2215 {
2216  MultiXactId multiVacLimit;
2217  MultiXactId multiWarnLimit;
2218  MultiXactId multiStopLimit;
2219  MultiXactId multiWrapLimit;
2220  MultiXactId curMulti;
2221  bool needs_offset_vacuum;
2222 
2223  Assert(MultiXactIdIsValid(oldest_datminmxid));
2224 
2225  /*
2226  * We pretend that a wrap will happen halfway through the multixact ID
2227  * space, but that's not really true, because multixacts wrap differently
2228  * from transaction IDs. Note that, separately from any concern about
2229  * multixact IDs wrapping, we must ensure that multixact members do not
2230  * wrap. Limits for that are set in SetOffsetVacuumLimit, not here.
2231  */
2232  multiWrapLimit = oldest_datminmxid + (MaxMultiXactId >> 1);
2233  if (multiWrapLimit < FirstMultiXactId)
2234  multiWrapLimit += FirstMultiXactId;
2235 
2236  /*
2237  * We'll refuse to continue assigning MultiXactIds once we get within 3M
2238  * multi of data loss. See SetTransactionIdLimit.
2239  */
2240  multiStopLimit = multiWrapLimit - 3000000;
2241  if (multiStopLimit < FirstMultiXactId)
2242  multiStopLimit -= FirstMultiXactId;
2243 
2244  /*
2245  * We'll start complaining loudly when we get within 40M multis of data
2246  * loss. This is kind of arbitrary, but if you let your gas gauge get
2247  * down to 2% of full, would you be looking for the next gas station? We
2248  * need to be fairly liberal about this number because there are lots of
2249  * scenarios where most transactions are done by automatic clients that
2250  * won't pay attention to warnings. (No, we're not gonna make this
2251  * configurable. If you know enough to configure it, you know enough to
2252  * not get in this kind of trouble in the first place.)
2253  */
2254  multiWarnLimit = multiWrapLimit - 40000000;
2255  if (multiWarnLimit < FirstMultiXactId)
2256  multiWarnLimit -= FirstMultiXactId;
2257 
2258  /*
2259  * We'll start trying to force autovacuums when oldest_datminmxid gets to
2260  * be more than autovacuum_multixact_freeze_max_age mxids old.
2261  *
2262  * Note: autovacuum_multixact_freeze_max_age is a PGC_POSTMASTER parameter
2263  * so that we don't have to worry about dealing with on-the-fly changes in
2264  * its value. See SetTransactionIdLimit.
2265  */
2266  multiVacLimit = oldest_datminmxid + autovacuum_multixact_freeze_max_age;
2267  if (multiVacLimit < FirstMultiXactId)
2268  multiVacLimit += FirstMultiXactId;
2269 
2270  /* Grab lock for just long enough to set the new limit values */
2271  LWLockAcquire(MultiXactGenLock, LW_EXCLUSIVE);
2272  MultiXactState->oldestMultiXactId = oldest_datminmxid;
2273  MultiXactState->oldestMultiXactDB = oldest_datoid;
2274  MultiXactState->multiVacLimit = multiVacLimit;
2275  MultiXactState->multiWarnLimit = multiWarnLimit;
2276  MultiXactState->multiStopLimit = multiStopLimit;
2277  MultiXactState->multiWrapLimit = multiWrapLimit;
2278  curMulti = MultiXactState->nextMXact;
2279  LWLockRelease(MultiXactGenLock);
2280 
2281  /* Log the info */
2282  ereport(DEBUG1,
2283  (errmsg_internal("MultiXactId wrap limit is %u, limited by database with OID %u",
2284  multiWrapLimit, oldest_datoid)));
2285 
2286  /*
2287  * Computing the actual limits is only possible once the data directory is
2288  * in a consistent state. There's no need to compute the limits while
2289  * still replaying WAL - no decisions about new multis are made even
2290  * though multixact creations might be replayed. So we'll only do further
2291  * checks after TrimMultiXact() has been called.
2292  */
2294  return;
2295 
2296  Assert(!InRecovery);
2297 
2298  /* Set limits for offset vacuum. */
2299  needs_offset_vacuum = SetOffsetVacuumLimit(is_startup);
2300 
2301  /*
2302  * If past the autovacuum force point, immediately signal an autovac
2303  * request. The reason for this is that autovac only processes one
2304  * database per invocation. Once it's finished cleaning up the oldest
2305  * database, it'll call here, and we'll signal the postmaster to start
2306  * another iteration immediately if there are still any old databases.
2307  */
2308  if ((MultiXactIdPrecedes(multiVacLimit, curMulti) ||
2309  needs_offset_vacuum) && IsUnderPostmaster)
2311 
2312  /* Give an immediate warning if past the wrap warn point */
2313  if (MultiXactIdPrecedes(multiWarnLimit, curMulti))
2314  {
2315  char *oldest_datname;
2316 
2317  /*
2318  * We can be called when not inside a transaction, for example during
2319  * StartupXLOG(). In such a case we cannot do database access, so we
2320  * must just report the oldest DB's OID.
2321  *
2322  * Note: it's also possible that get_database_name fails and returns
2323  * NULL, for example because the database just got dropped. We'll
2324  * still warn, even though the warning might now be unnecessary.
2325  */
2326  if (IsTransactionState())
2327  oldest_datname = get_database_name(oldest_datoid);
2328  else
2329  oldest_datname = NULL;
2330 
2331  if (oldest_datname)
2332  ereport(WARNING,
2333  (errmsg_plural("database \"%s\" must be vacuumed before %u more MultiXactId is used",
2334  "database \"%s\" must be vacuumed before %u more MultiXactIds are used",
2335  multiWrapLimit - curMulti,
2336  oldest_datname,
2337  multiWrapLimit - curMulti),
2338  errhint("To avoid a database shutdown, execute a database-wide VACUUM in that database.\n"
2339  "You might also need to commit or roll back old prepared transactions, or drop stale replication slots.")));
2340  else
2341  ereport(WARNING,
2342  (errmsg_plural("database with OID %u must be vacuumed before %u more MultiXactId is used",
2343  "database with OID %u must be vacuumed before %u more MultiXactIds are used",
2344  multiWrapLimit - curMulti,
2345  oldest_datoid,
2346  multiWrapLimit - curMulti),
2347  errhint("To avoid a database shutdown, execute a database-wide VACUUM in that database.\n"
2348  "You might also need to commit or roll back old prepared transactions, or drop stale replication slots.")));
2349  }
2350 }
char * get_database_name(Oid dbid)
Definition: dbcommands.c:2980
int errmsg_plural(const char *fmt_singular, const char *fmt_plural, unsigned long n,...)
Definition: elog.c:1179
int errmsg_internal(const char *fmt,...)
Definition: elog.c:1156
int errhint(const char *fmt,...)
Definition: elog.c:1316
#define WARNING
Definition: elog.h:36
static bool SetOffsetVacuumLimit(bool is_startup)
Definition: multixact.c:2560
#define MaxMultiXactId
Definition: multixact.h:26
void SendPostmasterSignal(PMSignalReason reason)
Definition: pmsignal.c:181
@ PMSIGNAL_START_AUTOVAC_LAUNCHER
Definition: pmsignal.h:38
MultiXactId multiWrapLimit
Definition: multixact.c:231
MultiXactId multiStopLimit
Definition: multixact.c:230
MultiXactId multiWarnLimit
Definition: multixact.c:229
MultiXactId multiVacLimit
Definition: multixact.c:228
bool IsTransactionState(void)
Definition: xact.c:378

References Assert(), autovacuum_multixact_freeze_max_age, DEBUG1, ereport, errhint(), errmsg_internal(), errmsg_plural(), MultiXactStateData::finishedStartup, FirstMultiXactId, get_database_name(), InRecovery, IsTransactionState(), IsUnderPostmaster, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MaxMultiXactId, MultiXactStateData::multiStopLimit, MultiXactStateData::multiVacLimit, MultiXactStateData::multiWarnLimit, MultiXactStateData::multiWrapLimit, MultiXactIdIsValid, MultiXactIdPrecedes(), MultiXactState, MultiXactStateData::nextMXact, MultiXactStateData::oldestMultiXactDB, MultiXactStateData::oldestMultiXactId, PMSIGNAL_START_AUTOVAC_LAUNCHER, SendPostmasterSignal(), SetOffsetVacuumLimit(), and WARNING.

Referenced by BootStrapXLOG(), multixact_redo(), MultiXactAdvanceOldest(), StartupXLOG(), TrimMultiXact(), and vac_truncate_clog().

◆ StartupMultiXact()

void StartupMultiXact ( void  )

Definition at line 2008 of file multixact.c.

2009 {
2012  int pageno;
2013 
2014  /*
2015  * Initialize offset's idea of the latest page number.
2016  */
2017  pageno = MultiXactIdToOffsetPage(multi);
2018  MultiXactOffsetCtl->shared->latest_page_number = pageno;
2019 
2020  /*
2021  * Initialize member's idea of the latest page number.
2022  */
2023  pageno = MXOffsetToMemberPage(offset);
2024  MultiXactMemberCtl->shared->latest_page_number = pageno;
2025 }

References MultiXactIdToOffsetPage, MultiXactMemberCtl, MultiXactOffsetCtl, MultiXactState, MXOffsetToMemberPage, MultiXactStateData::nextMXact, and MultiXactStateData::nextOffset.

Referenced by StartupXLOG().

◆ TrimMultiXact()

void TrimMultiXact ( void  )

Definition at line 2031 of file multixact.c.

2032 {
2033  MultiXactId nextMXact;
2034  MultiXactOffset offset;
2035  MultiXactId oldestMXact;
2036  Oid oldestMXactDB;
2037  int pageno;
2038  int entryno;
2039  int flagsoff;
2040 
2041  LWLockAcquire(MultiXactGenLock, LW_SHARED);
2042  nextMXact = MultiXactState->nextMXact;
2043  offset = MultiXactState->nextOffset;
2044  oldestMXact = MultiXactState->oldestMultiXactId;
2045  oldestMXactDB = MultiXactState->oldestMultiXactDB;
2046  LWLockRelease(MultiXactGenLock);
2047 
2048  /* Clean up offsets state */
2049  LWLockAcquire(MultiXactOffsetSLRULock, LW_EXCLUSIVE);
2050 
2051  /*
2052  * (Re-)Initialize our idea of the latest page number for offsets.
2053  */
2054  pageno = MultiXactIdToOffsetPage(nextMXact);
2055  MultiXactOffsetCtl->shared->latest_page_number = pageno;
2056 
2057  /*
2058  * Zero out the remainder of the current offsets page. See notes in
2059  * TrimCLOG() for background. Unlike CLOG, some WAL record covers every
2060  * pg_multixact SLRU mutation. Since, also unlike CLOG, we ignore the WAL
2061  * rule "write xlog before data," nextMXact successors may carry obsolete,
2062  * nonzero offset values. Zero those so case 2 of GetMultiXactIdMembers()
2063  * operates normally.
2064  */
2065  entryno = MultiXactIdToOffsetEntry(nextMXact);
2066  if (entryno != 0)
2067  {
2068  int slotno;
2069  MultiXactOffset *offptr;
2070 
2071  slotno = SimpleLruReadPage(MultiXactOffsetCtl, pageno, true, nextMXact);
2072  offptr = (MultiXactOffset *) MultiXactOffsetCtl->shared->page_buffer[slotno];
2073  offptr += entryno;
2074 
2075  MemSet(offptr, 0, BLCKSZ - (entryno * sizeof(MultiXactOffset)));
2076 
2077  MultiXactOffsetCtl->shared->page_dirty[slotno] = true;
2078  }
2079 
2080  LWLockRelease(MultiXactOffsetSLRULock);
2081 
2082  /* And the same for members */
2083  LWLockAcquire(MultiXactMemberSLRULock, LW_EXCLUSIVE);
2084 
2085  /*
2086  * (Re-)Initialize our idea of the latest page number for members.
2087  */
2088  pageno = MXOffsetToMemberPage(offset);
2089  MultiXactMemberCtl->shared->latest_page_number = pageno;
2090 
2091  /*
2092  * Zero out the remainder of the current members page. See notes in
2093  * TrimCLOG() for motivation.
2094  */
2095  flagsoff = MXOffsetToFlagsOffset(offset);
2096  if (flagsoff != 0)
2097  {
2098  int slotno;
2099  TransactionId *xidptr;
2100  int memberoff;
2101 
2102  memberoff = MXOffsetToMemberOffset(offset);
2103  slotno = SimpleLruReadPage(MultiXactMemberCtl, pageno, true, offset);
2104  xidptr = (TransactionId *)
2105  (MultiXactMemberCtl->shared->page_buffer[slotno] + memberoff);
2106 
2107  MemSet(xidptr, 0, BLCKSZ - memberoff);
2108 
2109  /*
2110  * Note: we don't need to zero out the flag bits in the remaining
2111  * members of the current group, because they are always reset before
2112  * writing.
2113  */
2114 
2115  MultiXactMemberCtl->shared->page_dirty[slotno] = true;
2116  }
2117 
2118  LWLockRelease(MultiXactMemberSLRULock);
2119 
2120  /* signal that we're officially up */
2121  LWLockAcquire(MultiXactGenLock, LW_EXCLUSIVE);
2123  LWLockRelease(MultiXactGenLock);
2124 
2125  /* Now compute how far away the next members wraparound is. */
2126  SetMultiXactIdLimit(oldestMXact, oldestMXactDB, true);
2127 }
unsigned int Oid
Definition: postgres_ext.h:31

References MultiXactStateData::finishedStartup, LW_EXCLUSIVE, LW_SHARED, LWLockAcquire(), LWLockRelease(), MemSet, MultiXactIdToOffsetEntry, MultiXactIdToOffsetPage, MultiXactMemberCtl, MultiXactOffsetCtl, MultiXactState, MXOffsetToFlagsOffset, MXOffsetToMemberOffset, MXOffsetToMemberPage, MultiXactStateData::nextMXact, MultiXactStateData::nextOffset, MultiXactStateData::oldestMultiXactDB, MultiXactStateData::oldestMultiXactId, SetMultiXactIdLimit(), and SimpleLruReadPage().

Referenced by StartupXLOG().

◆ TruncateMultiXact()

void TruncateMultiXact ( MultiXactId  newOldestMulti,
Oid  newOldestMultiDB 
)

Definition at line 2941 of file multixact.c.

2942 {
2943  MultiXactId oldestMulti;
2944  MultiXactId nextMulti;
2945  MultiXactOffset newOldestOffset;
2946  MultiXactOffset oldestOffset;
2947  MultiXactOffset nextOffset;
2948  mxtruncinfo trunc;
2949  MultiXactId earliest;
2950 
2953 
2954  /*
2955  * We can only allow one truncation to happen at once. Otherwise parts of
2956  * members might vanish while we're doing lookups or similar. There's no
2957  * need to have an interlock with creating new multis or such, since those
2958  * are constrained by the limits (which only grow, never shrink).
2959  */
2960  LWLockAcquire(MultiXactTruncationLock, LW_EXCLUSIVE);
2961 
2962  LWLockAcquire(MultiXactGenLock, LW_SHARED);
2963  nextMulti = MultiXactState->nextMXact;
2964  nextOffset = MultiXactState->nextOffset;
2965  oldestMulti = MultiXactState->oldestMultiXactId;
2966  LWLockRelease(MultiXactGenLock);
2967  Assert(MultiXactIdIsValid(oldestMulti));
2968 
2969  /*
2970  * Make sure to only attempt truncation if there's values to truncate
2971  * away. In normal processing values shouldn't go backwards, but there's
2972  * some corner cases (due to bugs) where that's possible.
2973  */
2974  if (MultiXactIdPrecedesOrEquals(newOldestMulti, oldestMulti))
2975  {
2976  LWLockRelease(MultiXactTruncationLock);
2977  return;
2978  }
2979 
2980  /*
2981  * Note we can't just plow ahead with the truncation; it's possible that
2982  * there are no segments to truncate, which is a problem because we are
2983  * going to attempt to read the offsets page to determine where to
2984  * truncate the members SLRU. So we first scan the directory to determine
2985  * the earliest offsets page number that we can read without error.
2986  *
2987  * When nextMXact is less than one segment away from multiWrapLimit,
2988  * SlruScanDirCbFindEarliest can find some early segment other than the
2989  * actual earliest. (MultiXactOffsetPagePrecedes(EARLIEST, LATEST)
2990  * returns false, because not all pairs of entries have the same answer.)
2991  * That can also arise when an earlier truncation attempt failed unlink()
2992  * or returned early from this function. The only consequence is
2993  * returning early, which wastes space that we could have liberated.
2994  *
2995  * NB: It's also possible that the page that oldestMulti is on has already
2996  * been truncated away, and we crashed before updating oldestMulti.
2997  */
2998  trunc.earliestExistingPage = -1;
3001  if (earliest < FirstMultiXactId)
3002  earliest = FirstMultiXactId;
3003 
3004  /* If there's nothing to remove, we can bail out early. */
3005  if (MultiXactIdPrecedes(oldestMulti, earliest))
3006  {
3007  LWLockRelease(MultiXactTruncationLock);
3008  return;
3009  }
3010 
3011  /*
3012  * First, compute the safe truncation point for MultiXactMember. This is
3013  * the starting offset of the oldest multixact.
3014  *
3015  * Hopefully, find_multixact_start will always work here, because we've
3016  * already checked that it doesn't precede the earliest MultiXact on disk.
3017  * But if it fails, don't truncate anything, and log a message.
3018  */
3019  if (oldestMulti == nextMulti)
3020  {
3021  /* there are NO MultiXacts */
3022  oldestOffset = nextOffset;
3023  }
3024  else if (!find_multixact_start(oldestMulti, &oldestOffset))
3025  {
3026  ereport(LOG,
3027  (errmsg("oldest MultiXact %u not found, earliest MultiXact %u, skipping truncation",
3028  oldestMulti, earliest)));
3029  LWLockRelease(MultiXactTruncationLock);
3030  return;
3031  }
3032 
3033  /*
3034  * Secondly compute up to where to truncate. Lookup the corresponding
3035  * member offset for newOldestMulti for that.
3036  */
3037  if (newOldestMulti == nextMulti)
3038  {
3039  /* there are NO MultiXacts */
3040  newOldestOffset = nextOffset;
3041  }
3042  else if (!find_multixact_start(newOldestMulti, &newOldestOffset))
3043  {
3044  ereport(LOG,
3045  (errmsg("cannot truncate up to MultiXact %u because it does not exist on disk, skipping truncation",
3046  newOldestMulti)));
3047  LWLockRelease(MultiXactTruncationLock);
3048  return;
3049  }
3050 
3051  elog(DEBUG1, "performing multixact truncation: "
3052  "offsets [%u, %u), offsets segments [%x, %x), "
3053  "members [%u, %u), members segments [%x, %x)",
3054  oldestMulti, newOldestMulti,
3055  MultiXactIdToOffsetSegment(oldestMulti),
3056  MultiXactIdToOffsetSegment(newOldestMulti),
3057  oldestOffset, newOldestOffset,
3058  MXOffsetToMemberSegment(oldestOffset),
3059  MXOffsetToMemberSegment(newOldestOffset));
3060 
3061  /*
3062  * Do truncation, and the WAL logging of the truncation, in a critical
3063  * section. That way offsets/members cannot get out of sync anymore, i.e.
3064  * once consistent the newOldestMulti will always exist in members, even
3065  * if we crashed in the wrong moment.
3066  */
3068 
3069  /*
3070  * Prevent checkpoints from being scheduled concurrently. This is critical
3071  * because otherwise a truncation record might not be replayed after a
3072  * crash/basebackup, even though the state of the data directory would
3073  * require it.
3074  */
3077 
3078  /* WAL log truncation */
3079  WriteMTruncateXlogRec(newOldestMultiDB,
3080  oldestMulti, newOldestMulti,
3081  oldestOffset, newOldestOffset);
3082 
3083  /*
3084  * Update in-memory limits before performing the truncation, while inside
3085  * the critical section: Have to do it before truncation, to prevent
3086  * concurrent lookups of those values. Has to be inside the critical
3087  * section as otherwise a future call to this function would error out,
3088  * while looking up the oldest member in offsets, if our caller crashes
3089  * before updating the limits.
3090  */
3091  LWLockAcquire(MultiXactGenLock, LW_EXCLUSIVE);
3092  MultiXactState->oldestMultiXactId = newOldestMulti;
3093  MultiXactState->oldestMultiXactDB = newOldestMultiDB;
3094  LWLockRelease(MultiXactGenLock);
3095 
3096  /* First truncate members */
3097  PerformMembersTruncation(oldestOffset, newOldestOffset);
3098 
3099  /* Then offsets */
3100  PerformOffsetsTruncation(oldestMulti, newOldestMulti);
3101 
3103 
3104  END_CRIT_SECTION();
3105  LWLockRelease(MultiXactTruncationLock);
3106 }
#define LOG
Definition: elog.h:31
#define START_CRIT_SECTION()
Definition: miscadmin.h:148
static void WriteMTruncateXlogRec(Oid oldestMultiDB, MultiXactId startTruncOff, MultiXactId endTruncOff, MultiXactOffset startTruncMemb, MultiXactOffset endTruncMemb)
Definition: multixact.c:3208
static bool find_multixact_start(MultiXactId multi, MultiXactOffset *result)
Definition: multixact.c:2735
bool MultiXactIdPrecedesOrEquals(MultiXactId multi1, MultiXactId multi2)
Definition: multixact.c:3170
static bool SlruScanDirCbFindEarliest(SlruCtl ctl, char *filename, int segpage, void *data)
Definition: multixact.c:2865
#define DELAY_CHKPT_START
Definition: proc.h:119
bool SlruScanDirectory(SlruCtl ctl, SlruScanCallback callback, void *data)
Definition: slru.c:1554
PGPROC * MyProc
Definition: proc.c:66
int delayChkptFlags
Definition: proc.h:231
int earliestExistingPage
Definition: multixact.c:2857
bool RecoveryInProgress(void)
Definition: xlog.c:5905

References Assert(), DEBUG1, DELAY_CHKPT_START, PGPROC::delayChkptFlags, mxtruncinfo::earliestExistingPage, elog(), END_CRIT_SECTION, ereport, errmsg(), find_multixact_start(), MultiXactStateData::finishedStartup, FirstMultiXactId, LOG, LW_EXCLUSIVE, LW_SHARED, LWLockAcquire(), LWLockRelease(), MULTIXACT_OFFSETS_PER_PAGE, MultiXactIdIsValid, MultiXactIdPrecedes(), MultiXactIdPrecedesOrEquals(), MultiXactIdToOffsetSegment, MultiXactOffsetCtl, MultiXactState, MXOffsetToMemberSegment, MyProc, MultiXactStateData::nextMXact, MultiXactStateData::nextOffset, MultiXactStateData::oldestMultiXactDB, MultiXactStateData::oldestMultiXactId, PerformMembersTruncation(), PerformOffsetsTruncation(), RecoveryInProgress(), SlruScanDirCbFindEarliest(), SlruScanDirectory(), START_CRIT_SECTION, and WriteMTruncateXlogRec().

Referenced by vac_truncate_clog().