PostgreSQL Source Code  git master
slot.c File Reference
#include "postgres.h"
#include <unistd.h>
#include <sys/stat.h>
#include "access/transam.h"
#include "access/xlog_internal.h"
#include "access/xlogrecovery.h"
#include "common/file_utils.h"
#include "common/string.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "postmaster/interrupt.h"
#include "replication/slotsync.h"
#include "replication/slot.h"
#include "replication/walsender_private.h"
#include "storage/fd.h"
#include "storage/ipc.h"
#include "storage/proc.h"
#include "storage/procarray.h"
#include "utils/builtins.h"
#include "utils/guc_hooks.h"
#include "utils/varlena.h"
Include dependency graph for slot.c:

Go to the source code of this file.

Data Structures

struct  ReplicationSlotOnDisk
 
struct  StandbySlotNamesConfigData
 

Macros

#define RS_INVAL_MAX_CAUSES   RS_INVAL_WAL_LEVEL
 
#define ReplicationSlotOnDiskConstantSize    offsetof(ReplicationSlotOnDisk, slotdata)
 
#define ReplicationSlotOnDiskNotChecksummedSize    offsetof(ReplicationSlotOnDisk, version)
 
#define ReplicationSlotOnDiskChecksummedSize    sizeof(ReplicationSlotOnDisk) - ReplicationSlotOnDiskNotChecksummedSize
 
#define ReplicationSlotOnDiskV2Size    sizeof(ReplicationSlotOnDisk) - ReplicationSlotOnDiskConstantSize
 
#define SLOT_MAGIC   0x1051CA1 /* format identifier */
 
#define SLOT_VERSION   5 /* version for new files */
 

Typedefs

typedef struct ReplicationSlotOnDisk ReplicationSlotOnDisk
 

Functions

 StaticAssertDecl (lengthof(SlotInvalidationCauses)==(RS_INVAL_MAX_CAUSES+1), "array length mismatch")
 
static void ReplicationSlotShmemExit (int code, Datum arg)
 
static void ReplicationSlotDropPtr (ReplicationSlot *slot)
 
static void RestoreSlotFromDisk (const char *name)
 
static void CreateSlotOnDisk (ReplicationSlot *slot)
 
static void SaveSlotToPath (ReplicationSlot *slot, const char *dir, int elevel)
 
Size ReplicationSlotsShmemSize (void)
 
void ReplicationSlotsShmemInit (void)
 
void ReplicationSlotInitialize (void)
 
bool ReplicationSlotValidateName (const char *name, int elevel)
 
void ReplicationSlotCreate (const char *name, bool db_specific, ReplicationSlotPersistency persistency, bool two_phase, bool failover, bool synced)
 
ReplicationSlotSearchNamedReplicationSlot (const char *name, bool need_lock)
 
int ReplicationSlotIndex (ReplicationSlot *slot)
 
bool ReplicationSlotName (int index, Name name)
 
void ReplicationSlotAcquire (const char *name, bool nowait)
 
void ReplicationSlotRelease (void)
 
void ReplicationSlotCleanup (bool synced_only)
 
void ReplicationSlotDrop (const char *name, bool nowait)
 
void ReplicationSlotAlter (const char *name, bool failover)
 
void ReplicationSlotDropAcquired (void)
 
void ReplicationSlotSave (void)
 
void ReplicationSlotMarkDirty (void)
 
void ReplicationSlotPersist (void)
 
void ReplicationSlotsComputeRequiredXmin (bool already_locked)
 
void ReplicationSlotsComputeRequiredLSN (void)
 
XLogRecPtr ReplicationSlotsComputeLogicalRestartLSN (void)
 
bool ReplicationSlotsCountDBSlots (Oid dboid, int *nslots, int *nactive)
 
void ReplicationSlotsDropDBSlots (Oid dboid)
 
void CheckSlotRequirements (void)
 
void CheckSlotPermissions (void)
 
void ReplicationSlotReserveWal (void)
 
static void ReportSlotInvalidation (ReplicationSlotInvalidationCause cause, bool terminating, int pid, NameData slotname, XLogRecPtr restart_lsn, XLogRecPtr oldestLSN, TransactionId snapshotConflictHorizon)
 
static bool InvalidatePossiblyObsoleteSlot (ReplicationSlotInvalidationCause cause, ReplicationSlot *s, XLogRecPtr oldestLSN, Oid dboid, TransactionId snapshotConflictHorizon, bool *invalidated)
 
bool InvalidateObsoleteReplicationSlots (ReplicationSlotInvalidationCause cause, XLogSegNo oldestSegno, Oid dboid, TransactionId snapshotConflictHorizon)
 
void CheckPointReplicationSlots (bool is_shutdown)
 
void StartupReplicationSlots (void)
 
ReplicationSlotInvalidationCause GetSlotInvalidationCause (const char *invalidation_reason)
 
static bool validate_standby_slots (char *rawname, List **elemlist)
 
bool check_standby_slot_names (char **newval, void **extra, GucSource source)
 
void assign_standby_slot_names (const char *newval, void *extra)
 
bool SlotExistsInStandbySlotNames (const char *slot_name)
 
bool StandbySlotsHaveCaughtup (XLogRecPtr wait_for_lsn, int elevel)
 
void WaitForStandbyConfirmation (XLogRecPtr wait_for_lsn)
 

Variables

const char *const SlotInvalidationCauses []
 
ReplicationSlotCtlDataReplicationSlotCtl = NULL
 
ReplicationSlotMyReplicationSlot = NULL
 
int max_replication_slots = 10
 
char * standby_slot_names
 
static StandbySlotNamesConfigDatastandby_slot_names_config
 
static XLogRecPtr ss_oldest_flush_lsn = InvalidXLogRecPtr
 

Macro Definition Documentation

◆ ReplicationSlotOnDiskChecksummedSize

#define ReplicationSlotOnDiskChecksummedSize    sizeof(ReplicationSlotOnDisk) - ReplicationSlotOnDiskNotChecksummedSize

Definition at line 125 of file slot.c.

◆ ReplicationSlotOnDiskConstantSize

#define ReplicationSlotOnDiskConstantSize    offsetof(ReplicationSlotOnDisk, slotdata)

Definition at line 119 of file slot.c.

◆ ReplicationSlotOnDiskNotChecksummedSize

#define ReplicationSlotOnDiskNotChecksummedSize    offsetof(ReplicationSlotOnDisk, version)

Definition at line 122 of file slot.c.

◆ ReplicationSlotOnDiskV2Size

#define ReplicationSlotOnDiskV2Size    sizeof(ReplicationSlotOnDisk) - ReplicationSlotOnDiskConstantSize

Definition at line 128 of file slot.c.

◆ RS_INVAL_MAX_CAUSES

#define RS_INVAL_MAX_CAUSES   RS_INVAL_WAL_LEVEL

Definition at line 113 of file slot.c.

◆ SLOT_MAGIC

#define SLOT_MAGIC   0x1051CA1 /* format identifier */

Definition at line 131 of file slot.c.

◆ SLOT_VERSION

#define SLOT_VERSION   5 /* version for new files */

Definition at line 132 of file slot.c.

Typedef Documentation

◆ ReplicationSlotOnDisk

Function Documentation

◆ assign_standby_slot_names()

void assign_standby_slot_names ( const char *  newval,
void *  extra 
)

Definition at line 2534 of file slot.c.

2535 {
2536  /*
2537  * The standby slots may have changed, so we must recompute the oldest
2538  * LSN.
2539  */
2541 
2543 }
static XLogRecPtr ss_oldest_flush_lsn
Definition: slot.c:157
static StandbySlotNamesConfigData * standby_slot_names_config
Definition: slot.c:151
#define InvalidXLogRecPtr
Definition: xlogdefs.h:28

References InvalidXLogRecPtr, ss_oldest_flush_lsn, and standby_slot_names_config.

◆ check_standby_slot_names()

bool check_standby_slot_names ( char **  newval,
void **  extra,
GucSource  source 
)

Definition at line 2480 of file slot.c.

2481 {
2482  char *rawname;
2483  char *ptr;
2484  List *elemlist;
2485  int size;
2486  bool ok;
2488 
2489  if ((*newval)[0] == '\0')
2490  return true;
2491 
2492  /* Need a modifiable copy of the GUC string */
2493  rawname = pstrdup(*newval);
2494 
2495  /* Now verify if the specified slots exist and have correct type */
2496  ok = validate_standby_slots(rawname, &elemlist);
2497 
2498  if (!ok || elemlist == NIL)
2499  {
2500  pfree(rawname);
2501  list_free(elemlist);
2502  return ok;
2503  }
2504 
2505  /* Compute the size required for the StandbySlotNamesConfigData struct */
2506  size = offsetof(StandbySlotNamesConfigData, slot_names);
2507  foreach_ptr(char, slot_name, elemlist)
2508  size += strlen(slot_name) + 1;
2509 
2510  /* GUC extra value must be guc_malloc'd, not palloc'd */
2512 
2513  /* Transform the data into StandbySlotNamesConfigData */
2514  config->nslotnames = list_length(elemlist);
2515 
2516  ptr = config->slot_names;
2517  foreach_ptr(char, slot_name, elemlist)
2518  {
2519  strcpy(ptr, slot_name);
2520  ptr += strlen(slot_name) + 1;
2521  }
2522 
2523  *extra = (void *) config;
2524 
2525  pfree(rawname);
2526  list_free(elemlist);
2527  return true;
2528 }
#define LOG
Definition: elog.h:31
void * guc_malloc(int elevel, size_t size)
Definition: guc.c:640
#define newval
void list_free(List *list)
Definition: list.c:1546
char * pstrdup(const char *in)
Definition: mcxt.c:1695
void pfree(void *pointer)
Definition: mcxt.c:1520
static int list_length(const List *l)
Definition: pg_list.h:152
#define NIL
Definition: pg_list.h:68
#define foreach_ptr(type, var, lst)
Definition: pg_list.h:469
static pg_noinline void Size size
Definition: slab.c:607
static bool validate_standby_slots(char *rawname, List **elemlist)
Definition: slot.c:2422
Definition: pg_list.h:54
char slot_names[FLEXIBLE_ARRAY_MEMBER]
Definition: slot.c:99

References foreach_ptr, guc_malloc(), list_free(), list_length(), LOG, newval, NIL, StandbySlotNamesConfigData::nslotnames, pfree(), pstrdup(), size, StandbySlotNamesConfigData::slot_names, and validate_standby_slots().

◆ CheckPointReplicationSlots()

void CheckPointReplicationSlots ( bool  is_shutdown)

Definition at line 1839 of file slot.c.

1840 {
1841  int i;
1842 
1843  elog(DEBUG1, "performing replication slot checkpoint");
1844 
1845  /*
1846  * Prevent any slot from being created/dropped while we're active. As we
1847  * explicitly do *not* want to block iterating over replication_slots or
1848  * acquiring a slot we cannot take the control lock - but that's OK,
1849  * because holding ReplicationSlotAllocationLock is strictly stronger, and
1850  * enough to guarantee that nobody can change the in_use bits on us.
1851  */
1852  LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED);
1853 
1854  for (i = 0; i < max_replication_slots; i++)
1855  {
1857  char path[MAXPGPATH];
1858 
1859  if (!s->in_use)
1860  continue;
1861 
1862  /* save the slot to disk, locking is handled in SaveSlotToPath() */
1863  sprintf(path, "pg_replslot/%s", NameStr(s->data.name));
1864 
1865  /*
1866  * Slot's data is not flushed each time the confirmed_flush LSN is
1867  * updated as that could lead to frequent writes. However, we decide
1868  * to force a flush of all logical slot's data at the time of shutdown
1869  * if the confirmed_flush LSN is changed since we last flushed it to
1870  * disk. This helps in avoiding an unnecessary retreat of the
1871  * confirmed_flush LSN after restart.
1872  */
1873  if (is_shutdown && SlotIsLogical(s))
1874  {
1875  SpinLockAcquire(&s->mutex);
1876 
1878 
1879  if (s->data.invalidated == RS_INVAL_NONE &&
1881  {
1882  s->just_dirtied = true;
1883  s->dirty = true;
1884  }
1885  SpinLockRelease(&s->mutex);
1886  }
1887 
1888  SaveSlotToPath(s, path, LOG);
1889  }
1890  LWLockRelease(ReplicationSlotAllocationLock);
1891 }
#define NameStr(name)
Definition: c.h:746
#define Assert(condition)
Definition: c.h:858
#define DEBUG1
Definition: elog.h:30
#define elog(elevel,...)
Definition: elog.h:224
int i
Definition: isn.c:73
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1170
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1783
@ LW_SHARED
Definition: lwlock.h:115
#define MAXPGPATH
#define sprintf
Definition: port.h:240
static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel)
Definition: slot.c:2020
int max_replication_slots
Definition: slot.c:141
ReplicationSlotCtlData * ReplicationSlotCtl
Definition: slot.c:135
@ RS_INVAL_NONE
Definition: slot.h:49
#define SlotIsLogical(slot)
Definition: slot.h:210
#define SpinLockRelease(lock)
Definition: spin.h:64
#define SpinLockAcquire(lock)
Definition: spin.h:62
ReplicationSlot replication_slots[1]
Definition: slot.h:221
XLogRecPtr confirmed_flush
Definition: slot.h:104
ReplicationSlotInvalidationCause invalidated
Definition: slot.h:96
slock_t mutex
Definition: slot.h:151
XLogRecPtr last_saved_confirmed_flush
Definition: slot.h:203
bool in_use
Definition: slot.h:154
bool just_dirtied
Definition: slot.h:160
bool dirty
Definition: slot.h:161
ReplicationSlotPersistentData data
Definition: slot.h:178

References Assert, ReplicationSlotPersistentData::confirmed_flush, ReplicationSlot::data, DEBUG1, ReplicationSlot::dirty, elog, i, ReplicationSlot::in_use, ReplicationSlotPersistentData::invalidated, ReplicationSlot::just_dirtied, ReplicationSlot::last_saved_confirmed_flush, LOG, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, MAXPGPATH, ReplicationSlot::mutex, ReplicationSlotPersistentData::name, NameStr, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, RS_INVAL_NONE, SaveSlotToPath(), SlotIsLogical, SpinLockAcquire, SpinLockRelease, and sprintf.

Referenced by CheckPointGuts().

◆ CheckSlotPermissions()

void CheckSlotPermissions ( void  )

Definition at line 1384 of file slot.c.

1385 {
1386  if (!has_rolreplication(GetUserId()))
1387  ereport(ERROR,
1388  (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
1389  errmsg("permission denied to use replication slots"),
1390  errdetail("Only roles with the %s attribute may use replication slots.",
1391  "REPLICATION")));
1392 }
int errdetail(const char *fmt,...)
Definition: elog.c:1203
int errcode(int sqlerrcode)
Definition: elog.c:857
int errmsg(const char *fmt,...)
Definition: elog.c:1070
#define ERROR
Definition: elog.h:39
#define ereport(elevel,...)
Definition: elog.h:149
Oid GetUserId(void)
Definition: miscinit.c:514
bool has_rolreplication(Oid roleid)
Definition: miscinit.c:711

References ereport, errcode(), errdetail(), errmsg(), ERROR, GetUserId(), and has_rolreplication().

Referenced by copy_replication_slot(), pg_create_logical_replication_slot(), pg_create_physical_replication_slot(), pg_drop_replication_slot(), pg_logical_slot_get_changes_guts(), pg_replication_slot_advance(), and pg_sync_replication_slots().

◆ CheckSlotRequirements()

void CheckSlotRequirements ( void  )

Definition at line 1362 of file slot.c.

1363 {
1364  /*
1365  * NB: Adding a new requirement likely means that RestoreSlotFromDisk()
1366  * needs the same check.
1367  */
1368 
1369  if (max_replication_slots == 0)
1370  ereport(ERROR,
1371  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
1372  errmsg("replication slots can only be used if \"max_replication_slots\" > 0")));
1373 
1375  ereport(ERROR,
1376  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
1377  errmsg("replication slots can only be used if \"wal_level\" >= \"replica\"")));
1378 }
int wal_level
Definition: xlog.c:131
@ WAL_LEVEL_REPLICA
Definition: xlog.h:73

References ereport, errcode(), errmsg(), ERROR, max_replication_slots, wal_level, and WAL_LEVEL_REPLICA.

Referenced by CheckLogicalDecodingRequirements(), copy_replication_slot(), pg_create_physical_replication_slot(), and pg_drop_replication_slot().

◆ CreateSlotOnDisk()

static void CreateSlotOnDisk ( ReplicationSlot slot)
static

Definition at line 1959 of file slot.c.

1960 {
1961  char tmppath[MAXPGPATH];
1962  char path[MAXPGPATH];
1963  struct stat st;
1964 
1965  /*
1966  * No need to take out the io_in_progress_lock, nobody else can see this
1967  * slot yet, so nobody else will write. We're reusing SaveSlotToPath which
1968  * takes out the lock, if we'd take the lock here, we'd deadlock.
1969  */
1970 
1971  sprintf(path, "pg_replslot/%s", NameStr(slot->data.name));
1972  sprintf(tmppath, "pg_replslot/%s.tmp", NameStr(slot->data.name));
1973 
1974  /*
1975  * It's just barely possible that some previous effort to create or drop a
1976  * slot with this name left a temp directory lying around. If that seems
1977  * to be the case, try to remove it. If the rmtree() fails, we'll error
1978  * out at the MakePGDirectory() below, so we don't bother checking
1979  * success.
1980  */
1981  if (stat(tmppath, &st) == 0 && S_ISDIR(st.st_mode))
1982  rmtree(tmppath, true);
1983 
1984  /* Create and fsync the temporary slot directory. */
1985  if (MakePGDirectory(tmppath) < 0)
1986  ereport(ERROR,
1988  errmsg("could not create directory \"%s\": %m",
1989  tmppath)));
1990  fsync_fname(tmppath, true);
1991 
1992  /* Write the actual state file. */
1993  slot->dirty = true; /* signal that we really need to write */
1994  SaveSlotToPath(slot, tmppath, ERROR);
1995 
1996  /* Rename the directory into place. */
1997  if (rename(tmppath, path) != 0)
1998  ereport(ERROR,
2000  errmsg("could not rename file \"%s\" to \"%s\": %m",
2001  tmppath, path)));
2002 
2003  /*
2004  * If we'd now fail - really unlikely - we wouldn't know whether this slot
2005  * would persist after an OS crash or not - so, force a restart. The
2006  * restart would try to fsync this again till it works.
2007  */
2009 
2010  fsync_fname(path, true);
2011  fsync_fname("pg_replslot", true);
2012 
2013  END_CRIT_SECTION();
2014 }
int errcode_for_file_access(void)
Definition: elog.c:880
int MakePGDirectory(const char *directoryName)
Definition: fd.c:3913
void fsync_fname(const char *fname, bool isdir)
Definition: fd.c:756
#define START_CRIT_SECTION()
Definition: miscadmin.h:149
#define END_CRIT_SECTION()
Definition: miscadmin.h:151
bool rmtree(const char *path, bool rmtopdir)
Definition: rmtree.c:50
#define stat
Definition: win32_port.h:284
#define S_ISDIR(m)
Definition: win32_port.h:325

References ReplicationSlot::data, ReplicationSlot::dirty, END_CRIT_SECTION, ereport, errcode_for_file_access(), errmsg(), ERROR, fsync_fname(), MakePGDirectory(), MAXPGPATH, ReplicationSlotPersistentData::name, NameStr, rmtree(), S_ISDIR, SaveSlotToPath(), sprintf, stat::st_mode, START_CRIT_SECTION, and stat.

Referenced by ReplicationSlotCreate().

◆ GetSlotInvalidationCause()

ReplicationSlotInvalidationCause GetSlotInvalidationCause ( const char *  invalidation_reason)

Definition at line 2394 of file slot.c.

2395 {
2398  bool found PG_USED_FOR_ASSERTS_ONLY = false;
2399 
2400  Assert(invalidation_reason);
2401 
2402  for (cause = RS_INVAL_NONE; cause <= RS_INVAL_MAX_CAUSES; cause++)
2403  {
2404  if (strcmp(SlotInvalidationCauses[cause], invalidation_reason) == 0)
2405  {
2406  found = true;
2407  result = cause;
2408  break;
2409  }
2410  }
2411 
2412  Assert(found);
2413  return result;
2414 }
#define PG_USED_FOR_ASSERTS_ONLY
Definition: c.h:182
#define RS_INVAL_MAX_CAUSES
Definition: slot.c:113
const char *const SlotInvalidationCauses[]
Definition: slot.c:105
ReplicationSlotInvalidationCause
Definition: slot.h:48

References Assert, PG_USED_FOR_ASSERTS_ONLY, RS_INVAL_MAX_CAUSES, RS_INVAL_NONE, and SlotInvalidationCauses.

Referenced by synchronize_slots().

◆ InvalidateObsoleteReplicationSlots()

bool InvalidateObsoleteReplicationSlots ( ReplicationSlotInvalidationCause  cause,
XLogSegNo  oldestSegno,
Oid  dboid,
TransactionId  snapshotConflictHorizon 
)

Definition at line 1783 of file slot.c.

1786 {
1787  XLogRecPtr oldestLSN;
1788  bool invalidated = false;
1789 
1790  Assert(cause != RS_INVAL_HORIZON || TransactionIdIsValid(snapshotConflictHorizon));
1791  Assert(cause != RS_INVAL_WAL_REMOVED || oldestSegno > 0);
1792  Assert(cause != RS_INVAL_NONE);
1793 
1794  if (max_replication_slots == 0)
1795  return invalidated;
1796 
1797  XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN);
1798 
1799 restart:
1800  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
1801  for (int i = 0; i < max_replication_slots; i++)
1802  {
1804 
1805  if (!s->in_use)
1806  continue;
1807 
1808  if (InvalidatePossiblyObsoleteSlot(cause, s, oldestLSN, dboid,
1809  snapshotConflictHorizon,
1810  &invalidated))
1811  {
1812  /* if the lock was released, start from scratch */
1813  goto restart;
1814  }
1815  }
1816  LWLockRelease(ReplicationSlotControlLock);
1817 
1818  /*
1819  * If any slots have been invalidated, recalculate the resource limits.
1820  */
1821  if (invalidated)
1822  {
1825  }
1826 
1827  return invalidated;
1828 }
void ReplicationSlotsComputeRequiredXmin(bool already_locked)
Definition: slot.c:1049
void ReplicationSlotsComputeRequiredLSN(void)
Definition: slot.c:1105
static bool InvalidatePossiblyObsoleteSlot(ReplicationSlotInvalidationCause cause, ReplicationSlot *s, XLogRecPtr oldestLSN, Oid dboid, TransactionId snapshotConflictHorizon, bool *invalidated)
Definition: slot.c:1543
@ RS_INVAL_WAL_REMOVED
Definition: slot.h:51
@ RS_INVAL_HORIZON
Definition: slot.h:53
#define TransactionIdIsValid(xid)
Definition: transam.h:41
int wal_segment_size
Definition: xlog.c:143
#define XLogSegNoOffsetToRecPtr(segno, offset, wal_segsz_bytes, dest)
uint64 XLogRecPtr
Definition: xlogdefs.h:21

References Assert, i, ReplicationSlot::in_use, InvalidatePossiblyObsoleteSlot(), LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotsComputeRequiredLSN(), ReplicationSlotsComputeRequiredXmin(), RS_INVAL_HORIZON, RS_INVAL_NONE, RS_INVAL_WAL_REMOVED, TransactionIdIsValid, wal_segment_size, and XLogSegNoOffsetToRecPtr.

Referenced by CreateCheckPoint(), CreateRestartPoint(), ResolveRecoveryConflictWithSnapshot(), and xlog_redo().

◆ InvalidatePossiblyObsoleteSlot()

static bool InvalidatePossiblyObsoleteSlot ( ReplicationSlotInvalidationCause  cause,
ReplicationSlot s,
XLogRecPtr  oldestLSN,
Oid  dboid,
TransactionId  snapshotConflictHorizon,
bool invalidated 
)
static

Definition at line 1543 of file slot.c.

1548 {
1549  int last_signaled_pid = 0;
1550  bool released_lock = false;
1551  bool terminated = false;
1552  TransactionId initial_effective_xmin = InvalidTransactionId;
1553  TransactionId initial_catalog_effective_xmin = InvalidTransactionId;
1554  XLogRecPtr initial_restart_lsn = InvalidXLogRecPtr;
1556 
1557  for (;;)
1558  {
1559  XLogRecPtr restart_lsn;
1560  NameData slotname;
1561  int active_pid = 0;
1562  ReplicationSlotInvalidationCause invalidation_cause = RS_INVAL_NONE;
1563 
1564  Assert(LWLockHeldByMeInMode(ReplicationSlotControlLock, LW_SHARED));
1565 
1566  if (!s->in_use)
1567  {
1568  if (released_lock)
1569  LWLockRelease(ReplicationSlotControlLock);
1570  break;
1571  }
1572 
1573  /*
1574  * Check if the slot needs to be invalidated. If it needs to be
1575  * invalidated, and is not currently acquired, acquire it and mark it
1576  * as having been invalidated. We do this with the spinlock held to
1577  * avoid race conditions -- for example the restart_lsn could move
1578  * forward, or the slot could be dropped.
1579  */
1580  SpinLockAcquire(&s->mutex);
1581 
1582  restart_lsn = s->data.restart_lsn;
1583 
1584  /* we do nothing if the slot is already invalid */
1585  if (s->data.invalidated == RS_INVAL_NONE)
1586  {
1587  /*
1588  * The slot's mutex will be released soon, and it is possible that
1589  * those values change since the process holding the slot has been
1590  * terminated (if any), so record them here to ensure that we
1591  * would report the correct invalidation cause.
1592  */
1593  if (!terminated)
1594  {
1595  initial_restart_lsn = s->data.restart_lsn;
1596  initial_effective_xmin = s->effective_xmin;
1597  initial_catalog_effective_xmin = s->effective_catalog_xmin;
1598  }
1599 
1600  switch (cause)
1601  {
1602  case RS_INVAL_WAL_REMOVED:
1603  if (initial_restart_lsn != InvalidXLogRecPtr &&
1604  initial_restart_lsn < oldestLSN)
1605  invalidation_cause = cause;
1606  break;
1607  case RS_INVAL_HORIZON:
1608  if (!SlotIsLogical(s))
1609  break;
1610  /* invalid DB oid signals a shared relation */
1611  if (dboid != InvalidOid && dboid != s->data.database)
1612  break;
1613  if (TransactionIdIsValid(initial_effective_xmin) &&
1614  TransactionIdPrecedesOrEquals(initial_effective_xmin,
1615  snapshotConflictHorizon))
1616  invalidation_cause = cause;
1617  else if (TransactionIdIsValid(initial_catalog_effective_xmin) &&
1618  TransactionIdPrecedesOrEquals(initial_catalog_effective_xmin,
1619  snapshotConflictHorizon))
1620  invalidation_cause = cause;
1621  break;
1622  case RS_INVAL_WAL_LEVEL:
1623  if (SlotIsLogical(s))
1624  invalidation_cause = cause;
1625  break;
1626  case RS_INVAL_NONE:
1627  pg_unreachable();
1628  }
1629  }
1630 
1631  /*
1632  * The invalidation cause recorded previously should not change while
1633  * the process owning the slot (if any) has been terminated.
1634  */
1635  Assert(!(invalidation_cause_prev != RS_INVAL_NONE && terminated &&
1636  invalidation_cause_prev != invalidation_cause));
1637 
1638  /* if there's no invalidation, we're done */
1639  if (invalidation_cause == RS_INVAL_NONE)
1640  {
1641  SpinLockRelease(&s->mutex);
1642  if (released_lock)
1643  LWLockRelease(ReplicationSlotControlLock);
1644  break;
1645  }
1646 
1647  slotname = s->data.name;
1648  active_pid = s->active_pid;
1649 
1650  /*
1651  * If the slot can be acquired, do so and mark it invalidated
1652  * immediately. Otherwise we'll signal the owning process, below, and
1653  * retry.
1654  */
1655  if (active_pid == 0)
1656  {
1657  MyReplicationSlot = s;
1658  s->active_pid = MyProcPid;
1659  s->data.invalidated = invalidation_cause;
1660 
1661  /*
1662  * XXX: We should consider not overwriting restart_lsn and instead
1663  * just rely on .invalidated.
1664  */
1665  if (invalidation_cause == RS_INVAL_WAL_REMOVED)
1667 
1668  /* Let caller know */
1669  *invalidated = true;
1670  }
1671 
1672  SpinLockRelease(&s->mutex);
1673 
1674  /*
1675  * The logical replication slots shouldn't be invalidated as GUC
1676  * max_slot_wal_keep_size is set to -1 during the binary upgrade. See
1677  * check_old_cluster_for_valid_slots() where we ensure that no
1678  * invalidated before the upgrade.
1679  */
1680  Assert(!(*invalidated && SlotIsLogical(s) && IsBinaryUpgrade));
1681 
1682  if (active_pid != 0)
1683  {
1684  /*
1685  * Prepare the sleep on the slot's condition variable before
1686  * releasing the lock, to close a possible race condition if the
1687  * slot is released before the sleep below.
1688  */
1690 
1691  LWLockRelease(ReplicationSlotControlLock);
1692  released_lock = true;
1693 
1694  /*
1695  * Signal to terminate the process that owns the slot, if we
1696  * haven't already signalled it. (Avoidance of repeated
1697  * signalling is the only reason for there to be a loop in this
1698  * routine; otherwise we could rely on caller's restart loop.)
1699  *
1700  * There is the race condition that other process may own the slot
1701  * after its current owner process is terminated and before this
1702  * process owns it. To handle that, we signal only if the PID of
1703  * the owning process has changed from the previous time. (This
1704  * logic assumes that the same PID is not reused very quickly.)
1705  */
1706  if (last_signaled_pid != active_pid)
1707  {
1708  ReportSlotInvalidation(invalidation_cause, true, active_pid,
1709  slotname, restart_lsn,
1710  oldestLSN, snapshotConflictHorizon);
1711 
1712  if (MyBackendType == B_STARTUP)
1713  (void) SendProcSignal(active_pid,
1716  else
1717  (void) kill(active_pid, SIGTERM);
1718 
1719  last_signaled_pid = active_pid;
1720  terminated = true;
1721  invalidation_cause_prev = invalidation_cause;
1722  }
1723 
1724  /* Wait until the slot is released. */
1726  WAIT_EVENT_REPLICATION_SLOT_DROP);
1727 
1728  /*
1729  * Re-acquire lock and start over; we expect to invalidate the
1730  * slot next time (unless another process acquires the slot in the
1731  * meantime).
1732  */
1733  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
1734  continue;
1735  }
1736  else
1737  {
1738  /*
1739  * We hold the slot now and have already invalidated it; flush it
1740  * to ensure that state persists.
1741  *
1742  * Don't want to hold ReplicationSlotControlLock across file
1743  * system operations, so release it now but be sure to tell caller
1744  * to restart from scratch.
1745  */
1746  LWLockRelease(ReplicationSlotControlLock);
1747  released_lock = true;
1748 
1749  /* Make sure the invalidated state persists across server restart */
1753 
1754  ReportSlotInvalidation(invalidation_cause, false, active_pid,
1755  slotname, restart_lsn,
1756  oldestLSN, snapshotConflictHorizon);
1757 
1758  /* done with this slot for now */
1759  break;
1760  }
1761  }
1762 
1763  Assert(released_lock == !LWLockHeldByMe(ReplicationSlotControlLock));
1764 
1765  return released_lock;
1766 }
#define pg_unreachable()
Definition: c.h:296
uint32 TransactionId
Definition: c.h:652
void ConditionVariablePrepareToSleep(ConditionVariable *cv)
void ConditionVariableSleep(ConditionVariable *cv, uint32 wait_event_info)
bool IsBinaryUpgrade
Definition: globals.c:118
int MyProcPid
Definition: globals.c:45
bool LWLockHeldByMe(LWLock *lock)
Definition: lwlock.c:1895
bool LWLockHeldByMeInMode(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1939
@ B_STARTUP
Definition: miscadmin.h:358
BackendType MyBackendType
Definition: miscinit.c:63
#define InvalidOid
Definition: postgres_ext.h:36
#define INVALID_PROC_NUMBER
Definition: procnumber.h:26
int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
Definition: procsignal.c:257
@ PROCSIG_RECOVERY_CONFLICT_LOGICALSLOT
Definition: procsignal.h:46
void ReplicationSlotMarkDirty(void)
Definition: slot.c:1010
ReplicationSlot * MyReplicationSlot
Definition: slot.c:138
void ReplicationSlotSave(void)
Definition: slot.c:992
void ReplicationSlotRelease(void)
Definition: slot.c:652
static void ReportSlotInvalidation(ReplicationSlotInvalidationCause cause, bool terminating, int pid, NameData slotname, XLogRecPtr restart_lsn, XLogRecPtr oldestLSN, TransactionId snapshotConflictHorizon)
Definition: slot.c:1477
@ RS_INVAL_WAL_LEVEL
Definition: slot.h:55
XLogRecPtr restart_lsn
Definition: slot.h:93
TransactionId effective_catalog_xmin
Definition: slot.h:175
pid_t active_pid
Definition: slot.h:157
TransactionId effective_xmin
Definition: slot.h:174
ConditionVariable active_cv
Definition: slot.h:184
Definition: c.h:741
bool TransactionIdPrecedesOrEquals(TransactionId id1, TransactionId id2)
Definition: transam.c:299
#define InvalidTransactionId
Definition: transam.h:31
#define kill(pid, sig)
Definition: win32_port.h:485

References ReplicationSlot::active_cv, ReplicationSlot::active_pid, Assert, B_STARTUP, ConditionVariablePrepareToSleep(), ConditionVariableSleep(), ReplicationSlot::data, ReplicationSlotPersistentData::database, ReplicationSlot::effective_catalog_xmin, ReplicationSlot::effective_xmin, ReplicationSlot::in_use, INVALID_PROC_NUMBER, ReplicationSlotPersistentData::invalidated, InvalidOid, InvalidTransactionId, InvalidXLogRecPtr, IsBinaryUpgrade, kill, LW_SHARED, LWLockAcquire(), LWLockHeldByMe(), LWLockHeldByMeInMode(), LWLockRelease(), ReplicationSlot::mutex, MyBackendType, MyProcPid, MyReplicationSlot, ReplicationSlotPersistentData::name, pg_unreachable, PG_USED_FOR_ASSERTS_ONLY, PROCSIG_RECOVERY_CONFLICT_LOGICALSLOT, ReplicationSlotMarkDirty(), ReplicationSlotRelease(), ReplicationSlotSave(), ReportSlotInvalidation(), ReplicationSlotPersistentData::restart_lsn, RS_INVAL_HORIZON, RS_INVAL_NONE, RS_INVAL_WAL_LEVEL, RS_INVAL_WAL_REMOVED, SendProcSignal(), SlotIsLogical, SpinLockAcquire, SpinLockRelease, TransactionIdIsValid, and TransactionIdPrecedesOrEquals().

Referenced by InvalidateObsoleteReplicationSlots().

◆ ReplicationSlotAcquire()

void ReplicationSlotAcquire ( const char *  name,
bool  nowait 
)

Definition at line 540 of file slot.c.

541 {
542  ReplicationSlot *s;
543  int active_pid;
544 
545  Assert(name != NULL);
546 
547 retry:
548  Assert(MyReplicationSlot == NULL);
549 
550  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
551 
552  /* Check if the slot exits with the given name. */
553  s = SearchNamedReplicationSlot(name, false);
554  if (s == NULL || !s->in_use)
555  {
556  LWLockRelease(ReplicationSlotControlLock);
557 
558  ereport(ERROR,
559  (errcode(ERRCODE_UNDEFINED_OBJECT),
560  errmsg("replication slot \"%s\" does not exist",
561  name)));
562  }
563 
564  /*
565  * This is the slot we want; check if it's active under some other
566  * process. In single user mode, we don't need this check.
567  */
568  if (IsUnderPostmaster)
569  {
570  /*
571  * Get ready to sleep on the slot in case it is active. (We may end
572  * up not sleeping, but we don't want to do this while holding the
573  * spinlock.)
574  */
575  if (!nowait)
577 
578  SpinLockAcquire(&s->mutex);
579  if (s->active_pid == 0)
580  s->active_pid = MyProcPid;
581  active_pid = s->active_pid;
582  SpinLockRelease(&s->mutex);
583  }
584  else
585  active_pid = MyProcPid;
586  LWLockRelease(ReplicationSlotControlLock);
587 
588  /*
589  * If we found the slot but it's already active in another process, we
590  * wait until the owning process signals us that it's been released, or
591  * error out.
592  */
593  if (active_pid != MyProcPid)
594  {
595  if (!nowait)
596  {
597  /* Wait here until we get signaled, and then restart */
599  WAIT_EVENT_REPLICATION_SLOT_DROP);
601  goto retry;
602  }
603 
604  ereport(ERROR,
605  (errcode(ERRCODE_OBJECT_IN_USE),
606  errmsg("replication slot \"%s\" is active for PID %d",
607  NameStr(s->data.name), active_pid)));
608  }
609  else if (!nowait)
610  ConditionVariableCancelSleep(); /* no sleep needed after all */
611 
612  /* Let everybody know we've modified this slot */
614 
615  /* We made this slot active, so it's ours now. */
616  MyReplicationSlot = s;
617 
618  /*
619  * The call to pgstat_acquire_replslot() protects against stats for a
620  * different slot, from before a restart or such, being present during
621  * pgstat_report_replslot().
622  */
623  if (SlotIsLogical(s))
625 
626  /*
627  * Reset the time since the slot has become inactive as the slot is active
628  * now.
629  */
630  SpinLockAcquire(&s->mutex);
631  s->inactive_since = 0;
632  SpinLockRelease(&s->mutex);
633 
634  if (am_walsender)
635  {
637  SlotIsLogical(s)
638  ? errmsg("acquired logical replication slot \"%s\"",
639  NameStr(s->data.name))
640  : errmsg("acquired physical replication slot \"%s\"",
641  NameStr(s->data.name)));
642  }
643 }
bool ConditionVariableCancelSleep(void)
void ConditionVariableBroadcast(ConditionVariable *cv)
bool IsUnderPostmaster
Definition: globals.c:117
void pgstat_acquire_replslot(ReplicationSlot *slot)
ReplicationSlot * SearchNamedReplicationSlot(const char *name, bool need_lock)
Definition: slot.c:464
TimestampTz inactive_since
Definition: slot.h:206
const char * name
bool am_walsender
Definition: walsender.c:115
bool log_replication_commands
Definition: walsender.c:125

References ReplicationSlot::active_cv, ReplicationSlot::active_pid, am_walsender, Assert, ConditionVariableBroadcast(), ConditionVariableCancelSleep(), ConditionVariablePrepareToSleep(), ConditionVariableSleep(), ReplicationSlot::data, DEBUG1, ereport, errcode(), errmsg(), ERROR, ReplicationSlot::in_use, ReplicationSlot::inactive_since, IsUnderPostmaster, LOG, log_replication_commands, LW_SHARED, LWLockAcquire(), LWLockRelease(), ReplicationSlot::mutex, MyProcPid, MyReplicationSlot, name, ReplicationSlotPersistentData::name, NameStr, pgstat_acquire_replslot(), SearchNamedReplicationSlot(), SlotIsLogical, SpinLockAcquire, and SpinLockRelease.

Referenced by binary_upgrade_logical_slot_has_caught_up(), drop_local_obsolete_slots(), pg_logical_slot_get_changes_guts(), pg_replication_slot_advance(), ReplicationSlotAlter(), ReplicationSlotDrop(), StartLogicalReplication(), StartReplication(), and synchronize_one_slot().

◆ ReplicationSlotAlter()

void ReplicationSlotAlter ( const char *  name,
bool  failover 
)

Definition at line 807 of file slot.c.

808 {
809  Assert(MyReplicationSlot == NULL);
810 
812 
814  ereport(ERROR,
815  errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
816  errmsg("cannot use %s with a physical replication slot",
817  "ALTER_REPLICATION_SLOT"));
818 
819  if (RecoveryInProgress())
820  {
821  /*
822  * Do not allow users to alter the slots which are currently being
823  * synced from the primary to the standby.
824  */
826  ereport(ERROR,
827  errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
828  errmsg("cannot alter replication slot \"%s\"", name),
829  errdetail("This slot is being synced from the primary server."));
830 
831  /*
832  * Do not allow users to enable failover on the standby as we do not
833  * support sync to the cascading standby.
834  */
835  if (failover)
836  ereport(ERROR,
837  errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
838  errmsg("cannot enable failover for a replication slot"
839  " on the standby"));
840  }
841 
842  /*
843  * Do not allow users to enable failover for temporary slots as we do not
844  * support syncing temporary slots to the standby.
845  */
846  if (failover && MyReplicationSlot->data.persistency == RS_TEMPORARY)
847  ereport(ERROR,
848  errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
849  errmsg("cannot enable failover for a temporary replication slot"));
850 
851  if (MyReplicationSlot->data.failover != failover)
852  {
854  MyReplicationSlot->data.failover = failover;
856 
859  }
860 
862 }
void ReplicationSlotAcquire(const char *name, bool nowait)
Definition: slot.c:540
@ RS_TEMPORARY
Definition: slot.h:37
#define SlotIsPhysical(slot)
Definition: slot.h:209
ReplicationSlotPersistency persistency
Definition: slot.h:74
bool RecoveryInProgress(void)
Definition: xlog.c:6290

References Assert, ReplicationSlot::data, ereport, errcode(), errdetail(), errmsg(), ERROR, ReplicationSlotPersistentData::failover, ReplicationSlot::mutex, MyReplicationSlot, name, ReplicationSlotPersistentData::persistency, RecoveryInProgress(), ReplicationSlotAcquire(), ReplicationSlotMarkDirty(), ReplicationSlotRelease(), ReplicationSlotSave(), RS_TEMPORARY, SlotIsPhysical, SpinLockAcquire, SpinLockRelease, and ReplicationSlotPersistentData::synced.

Referenced by AlterReplicationSlot().

◆ ReplicationSlotCleanup()

void ReplicationSlotCleanup ( bool  synced_only)

Definition at line 745 of file slot.c.

746 {
747  int i;
748 
749  Assert(MyReplicationSlot == NULL);
750 
751 restart:
752  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
753  for (i = 0; i < max_replication_slots; i++)
754  {
756 
757  if (!s->in_use)
758  continue;
759 
760  SpinLockAcquire(&s->mutex);
761  if ((s->active_pid == MyProcPid &&
762  (!synced_only || s->data.synced)))
763  {
765  SpinLockRelease(&s->mutex);
766  LWLockRelease(ReplicationSlotControlLock); /* avoid deadlock */
767 
769 
771  goto restart;
772  }
773  else
774  SpinLockRelease(&s->mutex);
775  }
776 
777  LWLockRelease(ReplicationSlotControlLock);
778 }
static void ReplicationSlotDropPtr(ReplicationSlot *slot)
Definition: slot.c:885

References ReplicationSlot::active_cv, ReplicationSlot::active_pid, Assert, ConditionVariableBroadcast(), ReplicationSlot::data, i, ReplicationSlot::in_use, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, MyProcPid, MyReplicationSlot, ReplicationSlotPersistentData::persistency, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotDropPtr(), RS_TEMPORARY, SpinLockAcquire, SpinLockRelease, and ReplicationSlotPersistentData::synced.

Referenced by PostgresMain(), ReplicationSlotShmemExit(), slotsync_failure_callback(), slotsync_worker_onexit(), SyncReplicationSlots(), and WalSndErrorCleanup().

◆ ReplicationSlotCreate()

void ReplicationSlotCreate ( const char *  name,
bool  db_specific,
ReplicationSlotPersistency  persistency,
bool  two_phase,
bool  failover,
bool  synced 
)

Definition at line 309 of file slot.c.

312 {
313  ReplicationSlot *slot = NULL;
314  int i;
315 
316  Assert(MyReplicationSlot == NULL);
317 
319 
320  if (failover)
321  {
322  /*
323  * Do not allow users to create the failover enabled slots on the
324  * standby as we do not support sync to the cascading standby.
325  *
326  * However, failover enabled slots can be created during slot
327  * synchronization because we need to retain the same values as the
328  * remote slot.
329  */
331  ereport(ERROR,
332  errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
333  errmsg("cannot enable failover for a replication slot created on the standby"));
334 
335  /*
336  * Do not allow users to create failover enabled temporary slots,
337  * because temporary slots will not be synced to the standby.
338  *
339  * However, failover enabled temporary slots can be created during
340  * slot synchronization. See the comments atop slotsync.c for details.
341  */
342  if (persistency == RS_TEMPORARY && !IsSyncingReplicationSlots())
343  ereport(ERROR,
344  errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
345  errmsg("cannot enable failover for a temporary replication slot"));
346  }
347 
348  /*
349  * If some other backend ran this code concurrently with us, we'd likely
350  * both allocate the same slot, and that would be bad. We'd also be at
351  * risk of missing a name collision. Also, we don't want to try to create
352  * a new slot while somebody's busy cleaning up an old one, because we
353  * might both be monkeying with the same directory.
354  */
355  LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE);
356 
357  /*
358  * Check for name collision, and identify an allocatable slot. We need to
359  * hold ReplicationSlotControlLock in shared mode for this, so that nobody
360  * else can change the in_use flags while we're looking at them.
361  */
362  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
363  for (i = 0; i < max_replication_slots; i++)
364  {
366 
367  if (s->in_use && strcmp(name, NameStr(s->data.name)) == 0)
368  ereport(ERROR,
370  errmsg("replication slot \"%s\" already exists", name)));
371  if (!s->in_use && slot == NULL)
372  slot = s;
373  }
374  LWLockRelease(ReplicationSlotControlLock);
375 
376  /* If all slots are in use, we're out of luck. */
377  if (slot == NULL)
378  ereport(ERROR,
379  (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED),
380  errmsg("all replication slots are in use"),
381  errhint("Free one or increase \"max_replication_slots\".")));
382 
383  /*
384  * Since this slot is not in use, nobody should be looking at any part of
385  * it other than the in_use field unless they're trying to allocate it.
386  * And since we hold ReplicationSlotAllocationLock, nobody except us can
387  * be doing that. So it's safe to initialize the slot.
388  */
389  Assert(!slot->in_use);
390  Assert(slot->active_pid == 0);
391 
392  /* first initialize persistent data */
393  memset(&slot->data, 0, sizeof(ReplicationSlotPersistentData));
394  namestrcpy(&slot->data.name, name);
395  slot->data.database = db_specific ? MyDatabaseId : InvalidOid;
396  slot->data.persistency = persistency;
397  slot->data.two_phase = two_phase;
399  slot->data.failover = failover;
400  slot->data.synced = synced;
401 
402  /* and then data only present in shared memory */
403  slot->just_dirtied = false;
404  slot->dirty = false;
412  slot->inactive_since = 0;
413 
414  /*
415  * Create the slot on disk. We haven't actually marked the slot allocated
416  * yet, so no special cleanup is required if this errors out.
417  */
418  CreateSlotOnDisk(slot);
419 
420  /*
421  * We need to briefly prevent any other backend from iterating over the
422  * slots while we flip the in_use flag. We also need to set the active
423  * flag while holding the ControlLock as otherwise a concurrent
424  * ReplicationSlotAcquire() could acquire the slot as well.
425  */
426  LWLockAcquire(ReplicationSlotControlLock, LW_EXCLUSIVE);
427 
428  slot->in_use = true;
429 
430  /* We can now mark the slot active, and that makes it our slot. */
431  SpinLockAcquire(&slot->mutex);
432  Assert(slot->active_pid == 0);
433  slot->active_pid = MyProcPid;
434  SpinLockRelease(&slot->mutex);
435  MyReplicationSlot = slot;
436 
437  LWLockRelease(ReplicationSlotControlLock);
438 
439  /*
440  * Create statistics entry for the new logical slot. We don't collect any
441  * stats for physical slots, so no need to create an entry for the same.
442  * See ReplicationSlotDropPtr for why we need to do this before releasing
443  * ReplicationSlotAllocationLock.
444  */
445  if (SlotIsLogical(slot))
447 
448  /*
449  * Now that the slot has been marked as in_use and active, it's safe to
450  * let somebody else try to allocate a slot.
451  */
452  LWLockRelease(ReplicationSlotAllocationLock);
453 
454  /* Let everybody know we've modified this slot */
456 }
int errhint(const char *fmt,...)
Definition: elog.c:1317
Oid MyDatabaseId
Definition: globals.c:91
@ LW_EXCLUSIVE
Definition: lwlock.h:114
void namestrcpy(Name name, const char *str)
Definition: name.c:233
static bool two_phase
void pgstat_create_replslot(ReplicationSlot *slot)
static void CreateSlotOnDisk(ReplicationSlot *slot)
Definition: slot.c:1959
bool ReplicationSlotValidateName(const char *name, int elevel)
Definition: slot.c:252
bool IsSyncingReplicationSlots(void)
Definition: slotsync.c:1650
#define ERRCODE_DUPLICATE_OBJECT
Definition: streamutil.c:32
XLogRecPtr candidate_xmin_lsn
Definition: slot.h:194
XLogRecPtr candidate_restart_valid
Definition: slot.h:195
XLogRecPtr candidate_restart_lsn
Definition: slot.h:196
TransactionId candidate_catalog_xmin
Definition: slot.h:193

References ReplicationSlot::active_cv, ReplicationSlot::active_pid, Assert, ReplicationSlot::candidate_catalog_xmin, ReplicationSlot::candidate_restart_lsn, ReplicationSlot::candidate_restart_valid, ReplicationSlot::candidate_xmin_lsn, ConditionVariableBroadcast(), CreateSlotOnDisk(), ReplicationSlot::data, ReplicationSlotPersistentData::database, ReplicationSlot::dirty, ReplicationSlot::effective_catalog_xmin, ReplicationSlot::effective_xmin, ereport, errcode(), ERRCODE_DUPLICATE_OBJECT, errhint(), errmsg(), ERROR, ReplicationSlotPersistentData::failover, i, ReplicationSlot::in_use, ReplicationSlot::inactive_since, InvalidOid, InvalidTransactionId, InvalidXLogRecPtr, IsSyncingReplicationSlots(), ReplicationSlot::just_dirtied, ReplicationSlot::last_saved_confirmed_flush, LW_EXCLUSIVE, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, MyDatabaseId, MyProcPid, MyReplicationSlot, name, ReplicationSlotPersistentData::name, NameStr, namestrcpy(), ReplicationSlotPersistentData::persistency, pgstat_create_replslot(), RecoveryInProgress(), ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotValidateName(), RS_TEMPORARY, SlotIsLogical, SpinLockAcquire, SpinLockRelease, ReplicationSlotPersistentData::synced, two_phase, ReplicationSlotPersistentData::two_phase, and ReplicationSlotPersistentData::two_phase_at.

Referenced by create_logical_replication_slot(), create_physical_replication_slot(), CreateReplicationSlot(), and synchronize_one_slot().

◆ ReplicationSlotDrop()

void ReplicationSlotDrop ( const char *  name,
bool  nowait 
)

Definition at line 784 of file slot.c.

785 {
786  Assert(MyReplicationSlot == NULL);
787 
788  ReplicationSlotAcquire(name, nowait);
789 
790  /*
791  * Do not allow users to drop the slots which are currently being synced
792  * from the primary to the standby.
793  */
795  ereport(ERROR,
796  errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
797  errmsg("cannot drop replication slot \"%s\"", name),
798  errdetail("This slot is being synced from the primary server."));
799 
801 }
void ReplicationSlotDropAcquired(void)
Definition: slot.c:868

References Assert, ReplicationSlot::data, ereport, errcode(), errdetail(), errmsg(), ERROR, MyReplicationSlot, name, RecoveryInProgress(), ReplicationSlotAcquire(), ReplicationSlotDropAcquired(), and ReplicationSlotPersistentData::synced.

Referenced by DropReplicationSlot(), and pg_drop_replication_slot().

◆ ReplicationSlotDropAcquired()

void ReplicationSlotDropAcquired ( void  )

Definition at line 868 of file slot.c.

869 {
871 
872  Assert(MyReplicationSlot != NULL);
873 
874  /* slot isn't acquired anymore */
875  MyReplicationSlot = NULL;
876 
878 }

References Assert, MyReplicationSlot, and ReplicationSlotDropPtr().

Referenced by drop_local_obsolete_slots(), ReplicationSlotDrop(), ReplicationSlotRelease(), and ReplicationSlotsDropDBSlots().

◆ ReplicationSlotDropPtr()

static void ReplicationSlotDropPtr ( ReplicationSlot slot)
static

Definition at line 885 of file slot.c.

886 {
887  char path[MAXPGPATH];
888  char tmppath[MAXPGPATH];
889 
890  /*
891  * If some other backend ran this code concurrently with us, we might try
892  * to delete a slot with a certain name while someone else was trying to
893  * create a slot with the same name.
894  */
895  LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE);
896 
897  /* Generate pathnames. */
898  sprintf(path, "pg_replslot/%s", NameStr(slot->data.name));
899  sprintf(tmppath, "pg_replslot/%s.tmp", NameStr(slot->data.name));
900 
901  /*
902  * Rename the slot directory on disk, so that we'll no longer recognize
903  * this as a valid slot. Note that if this fails, we've got to mark the
904  * slot inactive before bailing out. If we're dropping an ephemeral or a
905  * temporary slot, we better never fail hard as the caller won't expect
906  * the slot to survive and this might get called during error handling.
907  */
908  if (rename(path, tmppath) == 0)
909  {
910  /*
911  * We need to fsync() the directory we just renamed and its parent to
912  * make sure that our changes are on disk in a crash-safe fashion. If
913  * fsync() fails, we can't be sure whether the changes are on disk or
914  * not. For now, we handle that by panicking;
915  * StartupReplicationSlots() will try to straighten it out after
916  * restart.
917  */
919  fsync_fname(tmppath, true);
920  fsync_fname("pg_replslot", true);
922  }
923  else
924  {
925  bool fail_softly = slot->data.persistency != RS_PERSISTENT;
926 
927  SpinLockAcquire(&slot->mutex);
928  slot->active_pid = 0;
929  SpinLockRelease(&slot->mutex);
930 
931  /* wake up anyone waiting on this slot */
933 
934  ereport(fail_softly ? WARNING : ERROR,
936  errmsg("could not rename file \"%s\" to \"%s\": %m",
937  path, tmppath)));
938  }
939 
940  /*
941  * The slot is definitely gone. Lock out concurrent scans of the array
942  * long enough to kill it. It's OK to clear the active PID here without
943  * grabbing the mutex because nobody else can be scanning the array here,
944  * and nobody can be attached to this slot and thus access it without
945  * scanning the array.
946  *
947  * Also wake up processes waiting for it.
948  */
949  LWLockAcquire(ReplicationSlotControlLock, LW_EXCLUSIVE);
950  slot->active_pid = 0;
951  slot->in_use = false;
952  LWLockRelease(ReplicationSlotControlLock);
954 
955  /*
956  * Slot is dead and doesn't prevent resource removal anymore, recompute
957  * limits.
958  */
961 
962  /*
963  * If removing the directory fails, the worst thing that will happen is
964  * that the user won't be able to create a new slot with the same name
965  * until the next server restart. We warn about it, but that's all.
966  */
967  if (!rmtree(tmppath, true))
969  (errmsg("could not remove directory \"%s\"", tmppath)));
970 
971  /*
972  * Drop the statistics entry for the replication slot. Do this while
973  * holding ReplicationSlotAllocationLock so that we don't drop a
974  * statistics entry for another slot with the same name just created in
975  * another session.
976  */
977  if (SlotIsLogical(slot))
978  pgstat_drop_replslot(slot);
979 
980  /*
981  * We release this at the very end, so that nobody starts trying to create
982  * a slot while we're still cleaning up the detritus of the old one.
983  */
984  LWLockRelease(ReplicationSlotAllocationLock);
985 }
#define WARNING
Definition: elog.h:36
void pgstat_drop_replslot(ReplicationSlot *slot)
@ RS_PERSISTENT
Definition: slot.h:35

References ReplicationSlot::active_cv, ReplicationSlot::active_pid, ConditionVariableBroadcast(), ReplicationSlot::data, END_CRIT_SECTION, ereport, errcode_for_file_access(), errmsg(), ERROR, fsync_fname(), ReplicationSlot::in_use, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MAXPGPATH, ReplicationSlot::mutex, ReplicationSlotPersistentData::name, NameStr, ReplicationSlotPersistentData::persistency, pgstat_drop_replslot(), ReplicationSlotsComputeRequiredLSN(), ReplicationSlotsComputeRequiredXmin(), rmtree(), RS_PERSISTENT, SlotIsLogical, SpinLockAcquire, SpinLockRelease, sprintf, START_CRIT_SECTION, and WARNING.

Referenced by ReplicationSlotCleanup(), and ReplicationSlotDropAcquired().

◆ ReplicationSlotIndex()

int ReplicationSlotIndex ( ReplicationSlot slot)

◆ ReplicationSlotInitialize()

void ReplicationSlotInitialize ( void  )

Definition at line 224 of file slot.c.

225 {
227 }
void before_shmem_exit(pg_on_exit_callback function, Datum arg)
Definition: ipc.c:337
static void ReplicationSlotShmemExit(int code, Datum arg)
Definition: slot.c:233

References before_shmem_exit(), and ReplicationSlotShmemExit().

Referenced by BaseInit().

◆ ReplicationSlotMarkDirty()

◆ ReplicationSlotName()

bool ReplicationSlotName ( int  index,
Name  name 
)

Definition at line 513 of file slot.c.

514 {
515  ReplicationSlot *slot;
516  bool found;
517 
519 
520  /*
521  * Ensure that the slot cannot be dropped while we copy the name. Don't
522  * need the spinlock as the name of an existing slot cannot change.
523  */
524  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
525  found = slot->in_use;
526  if (slot->in_use)
527  namestrcpy(name, NameStr(slot->data.name));
528  LWLockRelease(ReplicationSlotControlLock);
529 
530  return found;
531 }
Definition: type.h:95

References ReplicationSlot::data, ReplicationSlot::in_use, LW_SHARED, LWLockAcquire(), LWLockRelease(), name, ReplicationSlotPersistentData::name, NameStr, namestrcpy(), ReplicationSlotCtlData::replication_slots, and ReplicationSlotCtl.

Referenced by pgstat_replslot_to_serialized_name_cb().

◆ ReplicationSlotPersist()

◆ ReplicationSlotRelease()

void ReplicationSlotRelease ( void  )

Definition at line 652 of file slot.c.

653 {
655  char *slotname = NULL; /* keep compiler quiet */
656  bool is_logical = false; /* keep compiler quiet */
657  TimestampTz now = 0;
658 
659  Assert(slot != NULL && slot->active_pid != 0);
660 
661  if (am_walsender)
662  {
663  slotname = pstrdup(NameStr(slot->data.name));
664  is_logical = SlotIsLogical(slot);
665  }
666 
667  if (slot->data.persistency == RS_EPHEMERAL)
668  {
669  /*
670  * Delete the slot. There is no !PANIC case where this is allowed to
671  * fail, all that may happen is an incomplete cleanup of the on-disk
672  * data.
673  */
675  }
676 
677  /*
678  * If slot needed to temporarily restrain both data and catalog xmin to
679  * create the catalog snapshot, remove that temporary constraint.
680  * Snapshots can only be exported while the initial snapshot is still
681  * acquired.
682  */
683  if (!TransactionIdIsValid(slot->data.xmin) &&
685  {
686  SpinLockAcquire(&slot->mutex);
688  SpinLockRelease(&slot->mutex);
690  }
691 
692  /*
693  * Set the time since the slot has become inactive. We get the current
694  * time beforehand to avoid system call while holding the spinlock.
695  */
697 
698  if (slot->data.persistency == RS_PERSISTENT)
699  {
700  /*
701  * Mark persistent slot inactive. We're not freeing it, just
702  * disconnecting, but wake up others that may be waiting for it.
703  */
704  SpinLockAcquire(&slot->mutex);
705  slot->active_pid = 0;
706  slot->inactive_since = now;
707  SpinLockRelease(&slot->mutex);
709  }
710  else
711  {
712  SpinLockAcquire(&slot->mutex);
713  slot->inactive_since = now;
714  SpinLockRelease(&slot->mutex);
715  }
716 
717  MyReplicationSlot = NULL;
718 
719  /* might not have been set when we've been a plain slot */
720  LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
723  LWLockRelease(ProcArrayLock);
724 
725  if (am_walsender)
726  {
728  is_logical
729  ? errmsg("released logical replication slot \"%s\"",
730  slotname)
731  : errmsg("released physical replication slot \"%s\"",
732  slotname));
733 
734  pfree(slotname);
735  }
736 }
TimestampTz GetCurrentTimestamp(void)
Definition: timestamp.c:1654
Datum now(PG_FUNCTION_ARGS)
Definition: timestamp.c:1618
int64 TimestampTz
Definition: timestamp.h:39
#define PROC_IN_LOGICAL_DECODING
Definition: proc.h:61
@ RS_EPHEMERAL
Definition: slot.h:36
PGPROC * MyProc
Definition: proc.c:66
PROC_HDR * ProcGlobal
Definition: proc.c:78
uint8 statusFlags
Definition: proc.h:238
int pgxactoff
Definition: proc.h:180
uint8 * statusFlags
Definition: proc.h:395
TransactionId xmin
Definition: slot.h:82

References ReplicationSlot::active_cv, ReplicationSlot::active_pid, am_walsender, Assert, ConditionVariableBroadcast(), ReplicationSlot::data, DEBUG1, ReplicationSlot::effective_xmin, ereport, errmsg(), GetCurrentTimestamp(), ReplicationSlot::inactive_since, InvalidTransactionId, LOG, log_replication_commands, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), ReplicationSlot::mutex, MyProc, MyReplicationSlot, ReplicationSlotPersistentData::name, NameStr, now(), ReplicationSlotPersistentData::persistency, pfree(), PGPROC::pgxactoff, PROC_IN_LOGICAL_DECODING, ProcGlobal, pstrdup(), ReplicationSlotDropAcquired(), ReplicationSlotsComputeRequiredXmin(), RS_EPHEMERAL, RS_PERSISTENT, SlotIsLogical, SpinLockAcquire, SpinLockRelease, PGPROC::statusFlags, PROC_HDR::statusFlags, TransactionIdIsValid, and ReplicationSlotPersistentData::xmin.

Referenced by binary_upgrade_logical_slot_has_caught_up(), copy_replication_slot(), CreateReplicationSlot(), InvalidatePossiblyObsoleteSlot(), pg_create_logical_replication_slot(), pg_create_physical_replication_slot(), pg_logical_slot_get_changes_guts(), pg_replication_slot_advance(), PostgresMain(), ReplicationSlotAlter(), ReplicationSlotShmemExit(), slotsync_failure_callback(), slotsync_worker_onexit(), StartLogicalReplication(), StartReplication(), synchronize_one_slot(), and WalSndErrorCleanup().

◆ ReplicationSlotReserveWal()

void ReplicationSlotReserveWal ( void  )

Definition at line 1401 of file slot.c.

1402 {
1404 
1405  Assert(slot != NULL);
1407 
1408  /*
1409  * The replication slot mechanism is used to prevent removal of required
1410  * WAL. As there is no interlock between this routine and checkpoints, WAL
1411  * segments could concurrently be removed when a now stale return value of
1412  * ReplicationSlotsComputeRequiredLSN() is used. In the unlikely case that
1413  * this happens we'll just retry.
1414  */
1415  while (true)
1416  {
1417  XLogSegNo segno;
1418  XLogRecPtr restart_lsn;
1419 
1420  /*
1421  * For logical slots log a standby snapshot and start logical decoding
1422  * at exactly that position. That allows the slot to start up more
1423  * quickly. But on a standby we cannot do WAL writes, so just use the
1424  * replay pointer; effectively, an attempt to create a logical slot on
1425  * standby will cause it to wait for an xl_running_xact record to be
1426  * logged independently on the primary, so that a snapshot can be
1427  * built using the record.
1428  *
1429  * None of this is needed (or indeed helpful) for physical slots as
1430  * they'll start replay at the last logged checkpoint anyway. Instead
1431  * return the location of the last redo LSN. While that slightly
1432  * increases the chance that we have to retry, it's where a base
1433  * backup has to start replay at.
1434  */
1435  if (SlotIsPhysical(slot))
1436  restart_lsn = GetRedoRecPtr();
1437  else if (RecoveryInProgress())
1438  restart_lsn = GetXLogReplayRecPtr(NULL);
1439  else
1440  restart_lsn = GetXLogInsertRecPtr();
1441 
1442  SpinLockAcquire(&slot->mutex);
1443  slot->data.restart_lsn = restart_lsn;
1444  SpinLockRelease(&slot->mutex);
1445 
1446  /* prevent WAL removal as fast as possible */
1448 
1449  /*
1450  * If all required WAL is still there, great, otherwise retry. The
1451  * slot should prevent further removal of WAL, unless there's a
1452  * concurrent ReplicationSlotsComputeRequiredLSN() after we've written
1453  * the new restart_lsn above, so normally we should never need to loop
1454  * more than twice.
1455  */
1457  if (XLogGetLastRemovedSegno() < segno)
1458  break;
1459  }
1460 
1461  if (!RecoveryInProgress() && SlotIsLogical(slot))
1462  {
1463  XLogRecPtr flushptr;
1464 
1465  /* make sure we have enough information to start */
1466  flushptr = LogStandbySnapshot();
1467 
1468  /* and make sure it's fsynced to disk */
1469  XLogFlush(flushptr);
1470  }
1471 }
XLogRecPtr LogStandbySnapshot(void)
Definition: standby.c:1285
XLogSegNo XLogGetLastRemovedSegno(void)
Definition: xlog.c:3747
XLogRecPtr GetRedoRecPtr(void)
Definition: xlog.c:6393
XLogRecPtr GetXLogInsertRecPtr(void)
Definition: xlog.c:9355
void XLogFlush(XLogRecPtr record)
Definition: xlog.c:2791
#define XLByteToSeg(xlrp, logSegNo, wal_segsz_bytes)
uint64 XLogSegNo
Definition: xlogdefs.h:48
XLogRecPtr GetXLogReplayRecPtr(TimeLineID *replayTLI)

References Assert, ReplicationSlot::data, GetRedoRecPtr(), GetXLogInsertRecPtr(), GetXLogReplayRecPtr(), InvalidXLogRecPtr, LogStandbySnapshot(), ReplicationSlot::mutex, MyReplicationSlot, RecoveryInProgress(), ReplicationSlotsComputeRequiredLSN(), ReplicationSlotPersistentData::restart_lsn, SlotIsLogical, SlotIsPhysical, SpinLockAcquire, SpinLockRelease, wal_segment_size, XLByteToSeg, XLogFlush(), and XLogGetLastRemovedSegno().

Referenced by create_physical_replication_slot(), CreateInitDecodingContext(), and CreateReplicationSlot().

◆ ReplicationSlotSave()

◆ ReplicationSlotsComputeLogicalRestartLSN()

XLogRecPtr ReplicationSlotsComputeLogicalRestartLSN ( void  )

Definition at line 1154 of file slot.c.

1155 {
1156  XLogRecPtr result = InvalidXLogRecPtr;
1157  int i;
1158 
1159  if (max_replication_slots <= 0)
1160  return InvalidXLogRecPtr;
1161 
1162  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
1163 
1164  for (i = 0; i < max_replication_slots; i++)
1165  {
1166  ReplicationSlot *s;
1167  XLogRecPtr restart_lsn;
1168  bool invalidated;
1169 
1171 
1172  /* cannot change while ReplicationSlotCtlLock is held */
1173  if (!s->in_use)
1174  continue;
1175 
1176  /* we're only interested in logical slots */
1177  if (!SlotIsLogical(s))
1178  continue;
1179 
1180  /* read once, it's ok if it increases while we're checking */
1181  SpinLockAcquire(&s->mutex);
1182  restart_lsn = s->data.restart_lsn;
1183  invalidated = s->data.invalidated != RS_INVAL_NONE;
1184  SpinLockRelease(&s->mutex);
1185 
1186  /* invalidated slots need not apply */
1187  if (invalidated)
1188  continue;
1189 
1190  if (restart_lsn == InvalidXLogRecPtr)
1191  continue;
1192 
1193  if (result == InvalidXLogRecPtr ||
1194  restart_lsn < result)
1195  result = restart_lsn;
1196  }
1197 
1198  LWLockRelease(ReplicationSlotControlLock);
1199 
1200  return result;
1201 }

References ReplicationSlot::data, i, ReplicationSlot::in_use, ReplicationSlotPersistentData::invalidated, InvalidXLogRecPtr, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotPersistentData::restart_lsn, RS_INVAL_NONE, SlotIsLogical, SpinLockAcquire, and SpinLockRelease.

Referenced by CheckPointLogicalRewriteHeap(), and CheckPointSnapBuild().

◆ ReplicationSlotsComputeRequiredLSN()

void ReplicationSlotsComputeRequiredLSN ( void  )

Definition at line 1105 of file slot.c.

1106 {
1107  int i;
1108  XLogRecPtr min_required = InvalidXLogRecPtr;
1109 
1110  Assert(ReplicationSlotCtl != NULL);
1111 
1112  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
1113  for (i = 0; i < max_replication_slots; i++)
1114  {
1116  XLogRecPtr restart_lsn;
1117  bool invalidated;
1118 
1119  if (!s->in_use)
1120  continue;
1121 
1122  SpinLockAcquire(&s->mutex);
1123  restart_lsn = s->data.restart_lsn;
1124  invalidated = s->data.invalidated != RS_INVAL_NONE;
1125  SpinLockRelease(&s->mutex);
1126 
1127  /* invalidated slots need not apply */
1128  if (invalidated)
1129  continue;
1130 
1131  if (restart_lsn != InvalidXLogRecPtr &&
1132  (min_required == InvalidXLogRecPtr ||
1133  restart_lsn < min_required))
1134  min_required = restart_lsn;
1135  }
1136  LWLockRelease(ReplicationSlotControlLock);
1137 
1138  XLogSetReplicationSlotMinimumLSN(min_required);
1139 }
void XLogSetReplicationSlotMinimumLSN(XLogRecPtr lsn)
Definition: xlog.c:2677

References Assert, ReplicationSlot::data, i, ReplicationSlot::in_use, ReplicationSlotPersistentData::invalidated, InvalidXLogRecPtr, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotPersistentData::restart_lsn, RS_INVAL_NONE, SpinLockAcquire, SpinLockRelease, and XLogSetReplicationSlotMinimumLSN().

Referenced by copy_replication_slot(), InvalidateObsoleteReplicationSlots(), LogicalConfirmReceivedLocation(), pg_replication_slot_advance(), PhysicalConfirmReceivedLocation(), ReplicationSlotDropPtr(), ReplicationSlotReserveWal(), reserve_wal_for_local_slot(), StartupReplicationSlots(), and update_local_synced_slot().

◆ ReplicationSlotsComputeRequiredXmin()

void ReplicationSlotsComputeRequiredXmin ( bool  already_locked)

Definition at line 1049 of file slot.c.

1050 {
1051  int i;
1053  TransactionId agg_catalog_xmin = InvalidTransactionId;
1054 
1055  Assert(ReplicationSlotCtl != NULL);
1056 
1057  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
1058 
1059  for (i = 0; i < max_replication_slots; i++)
1060  {
1062  TransactionId effective_xmin;
1063  TransactionId effective_catalog_xmin;
1064  bool invalidated;
1065 
1066  if (!s->in_use)
1067  continue;
1068 
1069  SpinLockAcquire(&s->mutex);
1070  effective_xmin = s->effective_xmin;
1071  effective_catalog_xmin = s->effective_catalog_xmin;
1072  invalidated = s->data.invalidated != RS_INVAL_NONE;
1073  SpinLockRelease(&s->mutex);
1074 
1075  /* invalidated slots need not apply */
1076  if (invalidated)
1077  continue;
1078 
1079  /* check the data xmin */
1080  if (TransactionIdIsValid(effective_xmin) &&
1081  (!TransactionIdIsValid(agg_xmin) ||
1082  TransactionIdPrecedes(effective_xmin, agg_xmin)))
1083  agg_xmin = effective_xmin;
1084 
1085  /* check the catalog xmin */
1086  if (TransactionIdIsValid(effective_catalog_xmin) &&
1087  (!TransactionIdIsValid(agg_catalog_xmin) ||
1088  TransactionIdPrecedes(effective_catalog_xmin, agg_catalog_xmin)))
1089  agg_catalog_xmin = effective_catalog_xmin;
1090  }
1091 
1092  LWLockRelease(ReplicationSlotControlLock);
1093 
1094  ProcArraySetReplicationSlotXmin(agg_xmin, agg_catalog_xmin, already_locked);
1095 }
void ProcArraySetReplicationSlotXmin(TransactionId xmin, TransactionId catalog_xmin, bool already_locked)
Definition: procarray.c:3930
bool TransactionIdPrecedes(TransactionId id1, TransactionId id2)
Definition: transam.c:280

References Assert, ReplicationSlot::data, ReplicationSlot::effective_catalog_xmin, ReplicationSlot::effective_xmin, i, ReplicationSlot::in_use, ReplicationSlotPersistentData::invalidated, InvalidTransactionId, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, ProcArraySetReplicationSlotXmin(), ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, RS_INVAL_NONE, SpinLockAcquire, SpinLockRelease, TransactionIdIsValid, and TransactionIdPrecedes().

Referenced by copy_replication_slot(), CreateInitDecodingContext(), InvalidateObsoleteReplicationSlots(), LogicalConfirmReceivedLocation(), pg_replication_slot_advance(), PhysicalReplicationSlotNewXmin(), ReplicationSlotDropPtr(), ReplicationSlotRelease(), StartupReplicationSlots(), synchronize_one_slot(), and update_local_synced_slot().

◆ ReplicationSlotsCountDBSlots()

bool ReplicationSlotsCountDBSlots ( Oid  dboid,
int *  nslots,
int *  nactive 
)

Definition at line 1212 of file slot.c.

1213 {
1214  int i;
1215 
1216  *nslots = *nactive = 0;
1217 
1218  if (max_replication_slots <= 0)
1219  return false;
1220 
1221  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
1222  for (i = 0; i < max_replication_slots; i++)
1223  {
1224  ReplicationSlot *s;
1225 
1227 
1228  /* cannot change while ReplicationSlotCtlLock is held */
1229  if (!s->in_use)
1230  continue;
1231 
1232  /* only logical slots are database specific, skip */
1233  if (!SlotIsLogical(s))
1234  continue;
1235 
1236  /* not our database, skip */
1237  if (s->data.database != dboid)
1238  continue;
1239 
1240  /* NB: intentionally counting invalidated slots */
1241 
1242  /* count slots with spinlock held */
1243  SpinLockAcquire(&s->mutex);
1244  (*nslots)++;
1245  if (s->active_pid != 0)
1246  (*nactive)++;
1247  SpinLockRelease(&s->mutex);
1248  }
1249  LWLockRelease(ReplicationSlotControlLock);
1250 
1251  if (*nslots > 0)
1252  return true;
1253  return false;
1254 }

References ReplicationSlot::active_pid, ReplicationSlot::data, ReplicationSlotPersistentData::database, i, ReplicationSlot::in_use, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, SlotIsLogical, SpinLockAcquire, and SpinLockRelease.

Referenced by dropdb().

◆ ReplicationSlotsDropDBSlots()

void ReplicationSlotsDropDBSlots ( Oid  dboid)

Definition at line 1270 of file slot.c.

1271 {
1272  int i;
1273 
1274  if (max_replication_slots <= 0)
1275  return;
1276 
1277 restart:
1278  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
1279  for (i = 0; i < max_replication_slots; i++)
1280  {
1281  ReplicationSlot *s;
1282  char *slotname;
1283  int active_pid;
1284 
1286 
1287  /* cannot change while ReplicationSlotCtlLock is held */
1288  if (!s->in_use)
1289  continue;
1290 
1291  /* only logical slots are database specific, skip */
1292  if (!SlotIsLogical(s))
1293  continue;
1294 
1295  /* not our database, skip */
1296  if (s->data.database != dboid)
1297  continue;
1298 
1299  /* NB: intentionally including invalidated slots */
1300 
1301  /* acquire slot, so ReplicationSlotDropAcquired can be reused */
1302  SpinLockAcquire(&s->mutex);
1303  /* can't change while ReplicationSlotControlLock is held */
1304  slotname = NameStr(s->data.name);
1305  active_pid = s->active_pid;
1306  if (active_pid == 0)
1307  {
1308  MyReplicationSlot = s;
1309  s->active_pid = MyProcPid;
1310  }
1311  SpinLockRelease(&s->mutex);
1312 
1313  /*
1314  * Even though we hold an exclusive lock on the database object a
1315  * logical slot for that DB can still be active, e.g. if it's
1316  * concurrently being dropped by a backend connected to another DB.
1317  *
1318  * That's fairly unlikely in practice, so we'll just bail out.
1319  *
1320  * The slot sync worker holds a shared lock on the database before
1321  * operating on synced logical slots to avoid conflict with the drop
1322  * happening here. The persistent synced slots are thus safe but there
1323  * is a possibility that the slot sync worker has created a temporary
1324  * slot (which stays active even on release) and we are trying to drop
1325  * that here. In practice, the chances of hitting this scenario are
1326  * less as during slot synchronization, the temporary slot is
1327  * immediately converted to persistent and thus is safe due to the
1328  * shared lock taken on the database. So, we'll just bail out in such
1329  * a case.
1330  *
1331  * XXX: We can consider shutting down the slot sync worker before
1332  * trying to drop synced temporary slots here.
1333  */
1334  if (active_pid)
1335  ereport(ERROR,
1336  (errcode(ERRCODE_OBJECT_IN_USE),
1337  errmsg("replication slot \"%s\" is active for PID %d",
1338  slotname, active_pid)));
1339 
1340  /*
1341  * To avoid duplicating ReplicationSlotDropAcquired() and to avoid
1342  * holding ReplicationSlotControlLock over filesystem operations,
1343  * release ReplicationSlotControlLock and use
1344  * ReplicationSlotDropAcquired.
1345  *
1346  * As that means the set of slots could change, restart scan from the
1347  * beginning each time we release the lock.
1348  */
1349  LWLockRelease(ReplicationSlotControlLock);
1351  goto restart;
1352  }
1353  LWLockRelease(ReplicationSlotControlLock);
1354 }

References ReplicationSlot::active_pid, ReplicationSlot::data, ReplicationSlotPersistentData::database, ereport, errcode(), errmsg(), ERROR, i, ReplicationSlot::in_use, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, MyProcPid, MyReplicationSlot, ReplicationSlotPersistentData::name, NameStr, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotDropAcquired(), SlotIsLogical, SpinLockAcquire, and SpinLockRelease.

Referenced by dbase_redo(), and dropdb().

◆ ReplicationSlotShmemExit()

static void ReplicationSlotShmemExit ( int  code,
Datum  arg 
)
static

Definition at line 233 of file slot.c.

234 {
235  /* Make sure active replication slots are released */
236  if (MyReplicationSlot != NULL)
238 
239  /* Also cleanup all the temporary slots. */
240  ReplicationSlotCleanup(false);
241 }
void ReplicationSlotCleanup(bool synced_only)
Definition: slot.c:745

References MyReplicationSlot, ReplicationSlotCleanup(), and ReplicationSlotRelease().

Referenced by ReplicationSlotInitialize().

◆ ReplicationSlotsShmemInit()

void ReplicationSlotsShmemInit ( void  )

Definition at line 189 of file slot.c.

190 {
191  bool found;
192 
193  if (max_replication_slots == 0)
194  return;
195 
197  ShmemInitStruct("ReplicationSlot Ctl", ReplicationSlotsShmemSize(),
198  &found);
199 
200  if (!found)
201  {
202  int i;
203 
204  /* First time through, so initialize */
206 
207  for (i = 0; i < max_replication_slots; i++)
208  {
210 
211  /* everything else is zeroed by the memset above */
212  SpinLockInit(&slot->mutex);
216  }
217  }
218 }
#define MemSet(start, val, len)
Definition: c.h:1020
void ConditionVariableInit(ConditionVariable *cv)
void LWLockInitialize(LWLock *lock, int tranche_id)
Definition: lwlock.c:709
@ LWTRANCHE_REPLICATION_SLOT_IO
Definition: lwlock.h:189
void * ShmemInitStruct(const char *name, Size size, bool *foundPtr)
Definition: shmem.c:387
Size ReplicationSlotsShmemSize(void)
Definition: slot.c:171
#define SpinLockInit(lock)
Definition: spin.h:60
LWLock io_in_progress_lock
Definition: slot.h:181

References ReplicationSlot::active_cv, ConditionVariableInit(), i, ReplicationSlot::io_in_progress_lock, LWLockInitialize(), LWTRANCHE_REPLICATION_SLOT_IO, max_replication_slots, MemSet, ReplicationSlot::mutex, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotsShmemSize(), ShmemInitStruct(), and SpinLockInit.

Referenced by CreateOrAttachShmemStructs().

◆ ReplicationSlotsShmemSize()

Size ReplicationSlotsShmemSize ( void  )

Definition at line 171 of file slot.c.

172 {
173  Size size = 0;
174 
175  if (max_replication_slots == 0)
176  return size;
177 
178  size = offsetof(ReplicationSlotCtlData, replication_slots);
179  size = add_size(size,
181 
182  return size;
183 }
size_t Size
Definition: c.h:605
Size add_size(Size s1, Size s2)
Definition: shmem.c:493
Size mul_size(Size s1, Size s2)
Definition: shmem.c:510

References add_size(), max_replication_slots, mul_size(), and size.

Referenced by CalculateShmemSize(), and ReplicationSlotsShmemInit().

◆ ReplicationSlotValidateName()

bool ReplicationSlotValidateName ( const char *  name,
int  elevel 
)

Definition at line 252 of file slot.c.

253 {
254  const char *cp;
255 
256  if (strlen(name) == 0)
257  {
258  ereport(elevel,
259  (errcode(ERRCODE_INVALID_NAME),
260  errmsg("replication slot name \"%s\" is too short",
261  name)));
262  return false;
263  }
264 
265  if (strlen(name) >= NAMEDATALEN)
266  {
267  ereport(elevel,
268  (errcode(ERRCODE_NAME_TOO_LONG),
269  errmsg("replication slot name \"%s\" is too long",
270  name)));
271  return false;
272  }
273 
274  for (cp = name; *cp; cp++)
275  {
276  if (!((*cp >= 'a' && *cp <= 'z')
277  || (*cp >= '0' && *cp <= '9')
278  || (*cp == '_')))
279  {
280  ereport(elevel,
281  (errcode(ERRCODE_INVALID_NAME),
282  errmsg("replication slot name \"%s\" contains invalid character",
283  name),
284  errhint("Replication slot names may only contain lower case letters, numbers, and the underscore character.")));
285  return false;
286  }
287  }
288  return true;
289 }
#define NAMEDATALEN

References ereport, errcode(), errhint(), errmsg(), name, and NAMEDATALEN.

Referenced by check_primary_slot_name(), parse_subscription_options(), ReplicationSlotCreate(), and StartupReorderBuffer().

◆ ReportSlotInvalidation()

static void ReportSlotInvalidation ( ReplicationSlotInvalidationCause  cause,
bool  terminating,
int  pid,
NameData  slotname,
XLogRecPtr  restart_lsn,
XLogRecPtr  oldestLSN,
TransactionId  snapshotConflictHorizon 
)
static

Definition at line 1477 of file slot.c.

1484 {
1485  StringInfoData err_detail;
1486  bool hint = false;
1487 
1488  initStringInfo(&err_detail);
1489 
1490  switch (cause)
1491  {
1492  case RS_INVAL_WAL_REMOVED:
1493  {
1494  unsigned long long ex = oldestLSN - restart_lsn;
1495 
1496  hint = true;
1497  appendStringInfo(&err_detail,
1498  ngettext("The slot's restart_lsn %X/%X exceeds the limit by %llu byte.",
1499  "The slot's restart_lsn %X/%X exceeds the limit by %llu bytes.",
1500  ex),
1501  LSN_FORMAT_ARGS(restart_lsn),
1502  ex);
1503  break;
1504  }
1505  case RS_INVAL_HORIZON:
1506  appendStringInfo(&err_detail, _("The slot conflicted with xid horizon %u."),
1507  snapshotConflictHorizon);
1508  break;
1509 
1510  case RS_INVAL_WAL_LEVEL:
1511  appendStringInfoString(&err_detail, _("Logical decoding on standby requires \"wal_level\" >= \"logical\" on the primary server."));
1512  break;
1513  case RS_INVAL_NONE:
1514  pg_unreachable();
1515  }
1516 
1517  ereport(LOG,
1518  terminating ?
1519  errmsg("terminating process %d to release replication slot \"%s\"",
1520  pid, NameStr(slotname)) :
1521  errmsg("invalidating obsolete replication slot \"%s\"",
1522  NameStr(slotname)),
1523  errdetail_internal("%s", err_detail.data),
1524  hint ? errhint("You might need to increase \"%s\".", "max_slot_wal_keep_size") : 0);
1525 
1526  pfree(err_detail.data);
1527 }
#define ngettext(s, p, n)
Definition: c.h:1181
int errdetail_internal(const char *fmt,...)
Definition: elog.c:1230
#define _(x)
Definition: elog.c:90
void appendStringInfo(StringInfo str, const char *fmt,...)
Definition: stringinfo.c:97
void appendStringInfoString(StringInfo str, const char *s)
Definition: stringinfo.c:182
void initStringInfo(StringInfo str)
Definition: stringinfo.c:59
#define LSN_FORMAT_ARGS(lsn)
Definition: xlogdefs.h:43

References _, appendStringInfo(), appendStringInfoString(), StringInfoData::data, ereport, errdetail_internal(), errhint(), errmsg(), initStringInfo(), LOG, LSN_FORMAT_ARGS, NameStr, ngettext, pfree(), pg_unreachable, RS_INVAL_HORIZON, RS_INVAL_NONE, RS_INVAL_WAL_LEVEL, and RS_INVAL_WAL_REMOVED.

Referenced by InvalidatePossiblyObsoleteSlot().

◆ RestoreSlotFromDisk()

static void RestoreSlotFromDisk ( const char *  name)
static

Definition at line 2175 of file slot.c.

2176 {
2178  int i;
2179  char slotdir[MAXPGPATH + 12];
2180  char path[MAXPGPATH + 22];
2181  int fd;
2182  bool restored = false;
2183  int readBytes;
2184  pg_crc32c checksum;
2185 
2186  /* no need to lock here, no concurrent access allowed yet */
2187 
2188  /* delete temp file if it exists */
2189  sprintf(slotdir, "pg_replslot/%s", name);
2190  sprintf(path, "%s/state.tmp", slotdir);
2191  if (unlink(path) < 0 && errno != ENOENT)
2192  ereport(PANIC,
2194  errmsg("could not remove file \"%s\": %m", path)));
2195 
2196  sprintf(path, "%s/state", slotdir);
2197 
2198  elog(DEBUG1, "restoring replication slot from \"%s\"", path);
2199 
2200  /* on some operating systems fsyncing a file requires O_RDWR */
2201  fd = OpenTransientFile(path, O_RDWR | PG_BINARY);
2202 
2203  /*
2204  * We do not need to handle this as we are rename()ing the directory into
2205  * place only after we fsync()ed the state file.
2206  */
2207  if (fd < 0)
2208  ereport(PANIC,
2210  errmsg("could not open file \"%s\": %m", path)));
2211 
2212  /*
2213  * Sync state file before we're reading from it. We might have crashed
2214  * while it wasn't synced yet and we shouldn't continue on that basis.
2215  */
2216  pgstat_report_wait_start(WAIT_EVENT_REPLICATION_SLOT_RESTORE_SYNC);
2217  if (pg_fsync(fd) != 0)
2218  ereport(PANIC,
2220  errmsg("could not fsync file \"%s\": %m",
2221  path)));
2223 
2224  /* Also sync the parent directory */
2226  fsync_fname(slotdir, true);
2227  END_CRIT_SECTION();
2228 
2229  /* read part of statefile that's guaranteed to be version independent */
2230  pgstat_report_wait_start(WAIT_EVENT_REPLICATION_SLOT_READ);
2231  readBytes = read(fd, &cp, ReplicationSlotOnDiskConstantSize);
2233  if (readBytes != ReplicationSlotOnDiskConstantSize)
2234  {
2235  if (readBytes < 0)
2236  ereport(PANIC,
2238  errmsg("could not read file \"%s\": %m", path)));
2239  else
2240  ereport(PANIC,
2242  errmsg("could not read file \"%s\": read %d of %zu",
2243  path, readBytes,
2245  }
2246 
2247  /* verify magic */
2248  if (cp.magic != SLOT_MAGIC)
2249  ereport(PANIC,
2251  errmsg("replication slot file \"%s\" has wrong magic number: %u instead of %u",
2252  path, cp.magic, SLOT_MAGIC)));
2253 
2254  /* verify version */
2255  if (cp.version != SLOT_VERSION)
2256  ereport(PANIC,
2258  errmsg("replication slot file \"%s\" has unsupported version %u",
2259  path, cp.version)));
2260 
2261  /* boundary check on length */
2263  ereport(PANIC,
2265  errmsg("replication slot file \"%s\" has corrupted length %u",
2266  path, cp.length)));
2267 
2268  /* Now that we know the size, read the entire file */
2269  pgstat_report_wait_start(WAIT_EVENT_REPLICATION_SLOT_READ);
2270  readBytes = read(fd,
2271  (char *) &cp + ReplicationSlotOnDiskConstantSize,
2272  cp.length);
2274  if (readBytes != cp.length)
2275  {
2276  if (readBytes < 0)
2277  ereport(PANIC,
2279  errmsg("could not read file \"%s\": %m", path)));
2280  else
2281  ereport(PANIC,
2283  errmsg("could not read file \"%s\": read %d of %zu",
2284  path, readBytes, (Size) cp.length)));
2285  }
2286 
2287  if (CloseTransientFile(fd) != 0)
2288  ereport(PANIC,
2290  errmsg("could not close file \"%s\": %m", path)));
2291 
2292  /* now verify the CRC */
2293  INIT_CRC32C(checksum);
2294  COMP_CRC32C(checksum,
2297  FIN_CRC32C(checksum);
2298 
2299  if (!EQ_CRC32C(checksum, cp.checksum))
2300  ereport(PANIC,
2301  (errmsg("checksum mismatch for replication slot file \"%s\": is %u, should be %u",
2302  path, checksum, cp.checksum)));
2303 
2304  /*
2305  * If we crashed with an ephemeral slot active, don't restore but delete
2306  * it.
2307  */
2309  {
2310  if (!rmtree(slotdir, true))
2311  {
2312  ereport(WARNING,
2313  (errmsg("could not remove directory \"%s\"",
2314  slotdir)));
2315  }
2316  fsync_fname("pg_replslot", true);
2317  return;
2318  }
2319 
2320  /*
2321  * Verify that requirements for the specific slot type are met. That's
2322  * important because if these aren't met we're not guaranteed to retain
2323  * all the necessary resources for the slot.
2324  *
2325  * NB: We have to do so *after* the above checks for ephemeral slots,
2326  * because otherwise a slot that shouldn't exist anymore could prevent
2327  * restarts.
2328  *
2329  * NB: Changing the requirements here also requires adapting
2330  * CheckSlotRequirements() and CheckLogicalDecodingRequirements().
2331  */
2333  ereport(FATAL,
2334  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
2335  errmsg("logical replication slot \"%s\" exists, but \"wal_level\" < \"logical\"",
2336  NameStr(cp.slotdata.name)),
2337  errhint("Change \"wal_level\" to be \"logical\" or higher.")));
2338  else if (wal_level < WAL_LEVEL_REPLICA)
2339  ereport(FATAL,
2340  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
2341  errmsg("physical replication slot \"%s\" exists, but \"wal_level\" < \"replica\"",
2342  NameStr(cp.slotdata.name)),
2343  errhint("Change \"wal_level\" to be \"replica\" or higher.")));
2344 
2345  /* nothing can be active yet, don't lock anything */
2346  for (i = 0; i < max_replication_slots; i++)
2347  {
2348  ReplicationSlot *slot;
2349 
2351 
2352  if (slot->in_use)
2353  continue;
2354 
2355  /* restore the entire set of persistent data */
2356  memcpy(&slot->data, &cp.slotdata,
2358 
2359  /* initialize in memory state */
2360  slot->effective_xmin = cp.slotdata.xmin;
2363 
2368 
2369  slot->in_use = true;
2370  slot->active_pid = 0;
2371 
2372  /*
2373  * Set the time since the slot has become inactive after loading the
2374  * slot from the disk into memory. Whoever acquires the slot i.e.
2375  * makes the slot active will reset it.
2376  */
2378 
2379  restored = true;
2380  break;
2381  }
2382 
2383  if (!restored)
2384  ereport(FATAL,
2385  (errmsg("too many replication slots active before shutdown"),
2386  errhint("Increase \"max_replication_slots\" and try again.")));
2387 }
#define PG_BINARY
Definition: c.h:1273
#define FATAL
Definition: elog.h:41
#define PANIC
Definition: elog.h:42
int CloseTransientFile(int fd)
Definition: fd.c:2809
int pg_fsync(int fd)
Definition: fd.c:386
int OpenTransientFile(const char *fileName, int fileFlags)
Definition: fd.c:2633
#define read(a, b, c)
Definition: win32.h:13
#define ERRCODE_DATA_CORRUPTED
Definition: pg_basebackup.c:41
uint32 pg_crc32c
Definition: pg_crc32c.h:38
#define COMP_CRC32C(crc, data, len)
Definition: pg_crc32c.h:98
#define EQ_CRC32C(c1, c2)
Definition: pg_crc32c.h:42
#define INIT_CRC32C(crc)
Definition: pg_crc32c.h:41
#define FIN_CRC32C(crc)
Definition: pg_crc32c.h:103
static int fd(const char *x, int i)
Definition: preproc-init.c:105
#define ReplicationSlotOnDiskChecksummedSize
Definition: slot.c:125
#define ReplicationSlotOnDiskNotChecksummedSize
Definition: slot.c:122
#define ReplicationSlotOnDiskV2Size
Definition: slot.c:128
#define SLOT_VERSION
Definition: slot.c:132
#define SLOT_MAGIC
Definition: slot.c:131
#define ReplicationSlotOnDiskConstantSize
Definition: slot.c:119
uint32 version
Definition: slot.c:73
ReplicationSlotPersistentData slotdata
Definition: slot.c:81
pg_crc32c checksum
Definition: slot.c:70
TransactionId catalog_xmin
Definition: slot.h:90
static void pgstat_report_wait_start(uint32 wait_event_info)
Definition: wait_event.h:82
static void pgstat_report_wait_end(void)
Definition: wait_event.h:98
@ WAL_LEVEL_LOGICAL
Definition: xlog.h:74

References ReplicationSlot::active_pid, ReplicationSlot::candidate_catalog_xmin, ReplicationSlot::candidate_restart_lsn, ReplicationSlot::candidate_restart_valid, ReplicationSlot::candidate_xmin_lsn, ReplicationSlotPersistentData::catalog_xmin, ReplicationSlotOnDisk::checksum, CloseTransientFile(), COMP_CRC32C, ReplicationSlotPersistentData::confirmed_flush, ReplicationSlot::data, ReplicationSlotPersistentData::database, DEBUG1, ReplicationSlot::effective_catalog_xmin, ReplicationSlot::effective_xmin, elog, END_CRIT_SECTION, EQ_CRC32C, ereport, errcode(), ERRCODE_DATA_CORRUPTED, errcode_for_file_access(), errhint(), errmsg(), FATAL, fd(), FIN_CRC32C, fsync_fname(), GetCurrentTimestamp(), i, ReplicationSlot::in_use, ReplicationSlot::inactive_since, INIT_CRC32C, InvalidOid, InvalidTransactionId, InvalidXLogRecPtr, ReplicationSlot::last_saved_confirmed_flush, ReplicationSlotOnDisk::length, ReplicationSlotOnDisk::magic, max_replication_slots, MAXPGPATH, name, ReplicationSlotPersistentData::name, NameStr, OpenTransientFile(), PANIC, ReplicationSlotPersistentData::persistency, PG_BINARY, pg_fsync(), pgstat_report_wait_end(), pgstat_report_wait_start(), read, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotOnDiskChecksummedSize, ReplicationSlotOnDiskConstantSize, ReplicationSlotOnDiskNotChecksummedSize, ReplicationSlotOnDiskV2Size, rmtree(), RS_PERSISTENT, SLOT_MAGIC, SLOT_VERSION, ReplicationSlotOnDisk::slotdata, sprintf, START_CRIT_SECTION, ReplicationSlotOnDisk::version, wal_level, WAL_LEVEL_LOGICAL, WAL_LEVEL_REPLICA, WARNING, and ReplicationSlotPersistentData::xmin.

Referenced by StartupReplicationSlots().

◆ SaveSlotToPath()

static void SaveSlotToPath ( ReplicationSlot slot,
const char *  dir,
int  elevel 
)
static

Definition at line 2020 of file slot.c.

2021 {
2022  char tmppath[MAXPGPATH];
2023  char path[MAXPGPATH];
2024  int fd;
2026  bool was_dirty;
2027 
2028  /* first check whether there's something to write out */
2029  SpinLockAcquire(&slot->mutex);
2030  was_dirty = slot->dirty;
2031  slot->just_dirtied = false;
2032  SpinLockRelease(&slot->mutex);
2033 
2034  /* and don't do anything if there's nothing to write */
2035  if (!was_dirty)
2036  return;
2037 
2039 
2040  /* silence valgrind :( */
2041  memset(&cp, 0, sizeof(ReplicationSlotOnDisk));
2042 
2043  sprintf(tmppath, "%s/state.tmp", dir);
2044  sprintf(path, "%s/state", dir);
2045 
2046  fd = OpenTransientFile(tmppath, O_CREAT | O_EXCL | O_WRONLY | PG_BINARY);
2047  if (fd < 0)
2048  {
2049  /*
2050  * If not an ERROR, then release the lock before returning. In case
2051  * of an ERROR, the error recovery path automatically releases the
2052  * lock, but no harm in explicitly releasing even in that case. Note
2053  * that LWLockRelease() could affect errno.
2054  */
2055  int save_errno = errno;
2056 
2058  errno = save_errno;
2059  ereport(elevel,
2061  errmsg("could not create file \"%s\": %m",
2062  tmppath)));
2063  return;
2064  }
2065 
2066  cp.magic = SLOT_MAGIC;
2067  INIT_CRC32C(cp.checksum);
2068  cp.version = SLOT_VERSION;
2070 
2071  SpinLockAcquire(&slot->mutex);
2072 
2073  memcpy(&cp.slotdata, &slot->data, sizeof(ReplicationSlotPersistentData));
2074 
2075  SpinLockRelease(&slot->mutex);
2076 
2077  COMP_CRC32C(cp.checksum,
2078  (char *) (&cp) + ReplicationSlotOnDiskNotChecksummedSize,
2080  FIN_CRC32C(cp.checksum);
2081 
2082  errno = 0;
2083  pgstat_report_wait_start(WAIT_EVENT_REPLICATION_SLOT_WRITE);
2084  if ((write(fd, &cp, sizeof(cp))) != sizeof(cp))
2085  {
2086  int save_errno = errno;
2087 
2091 
2092  /* if write didn't set errno, assume problem is no disk space */
2093  errno = save_errno ? save_errno : ENOSPC;
2094  ereport(elevel,
2096  errmsg("could not write to file \"%s\": %m",
2097  tmppath)));
2098  return;
2099  }
2101 
2102  /* fsync the temporary file */
2103  pgstat_report_wait_start(WAIT_EVENT_REPLICATION_SLOT_SYNC);
2104  if (pg_fsync(fd) != 0)
2105  {
2106  int save_errno = errno;
2107 
2111  errno = save_errno;
2112  ereport(elevel,
2114  errmsg("could not fsync file \"%s\": %m",
2115  tmppath)));
2116  return;
2117  }
2119 
2120  if (CloseTransientFile(fd) != 0)
2121  {
2122  int save_errno = errno;
2123 
2125  errno = save_errno;
2126  ereport(elevel,
2128  errmsg("could not close file \"%s\": %m",
2129  tmppath)));
2130  return;
2131  }
2132 
2133  /* rename to permanent file, fsync file and directory */
2134  if (rename(tmppath, path) != 0)
2135  {
2136  int save_errno = errno;
2137 
2139  errno = save_errno;
2140  ereport(elevel,
2142  errmsg("could not rename file \"%s\" to \"%s\": %m",
2143  tmppath, path)));
2144  return;
2145  }
2146 
2147  /*
2148  * Check CreateSlotOnDisk() for the reasoning of using a critical section.
2149  */
2151 
2152  fsync_fname(path, false);
2153  fsync_fname(dir, true);
2154  fsync_fname("pg_replslot", true);
2155 
2156  END_CRIT_SECTION();
2157 
2158  /*
2159  * Successfully wrote, unset dirty bit, unless somebody dirtied again
2160  * already and remember the confirmed_flush LSN value.
2161  */
2162  SpinLockAcquire(&slot->mutex);
2163  if (!slot->just_dirtied)
2164  slot->dirty = false;
2166  SpinLockRelease(&slot->mutex);
2167 
2169 }
#define write(a, b, c)
Definition: win32.h:14

References ReplicationSlotOnDisk::checksum, CloseTransientFile(), COMP_CRC32C, ReplicationSlotPersistentData::confirmed_flush, ReplicationSlot::data, ReplicationSlot::dirty, END_CRIT_SECTION, ereport, errcode_for_file_access(), errmsg(), fd(), FIN_CRC32C, fsync_fname(), INIT_CRC32C, ReplicationSlot::io_in_progress_lock, ReplicationSlot::just_dirtied, ReplicationSlot::last_saved_confirmed_flush, ReplicationSlotOnDisk::length, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), ReplicationSlotOnDisk::magic, MAXPGPATH, ReplicationSlot::mutex, OpenTransientFile(), PG_BINARY, pg_fsync(), pgstat_report_wait_end(), pgstat_report_wait_start(), ReplicationSlotOnDiskChecksummedSize, ReplicationSlotOnDiskNotChecksummedSize, ReplicationSlotOnDiskV2Size, SLOT_MAGIC, SLOT_VERSION, ReplicationSlotOnDisk::slotdata, SpinLockAcquire, SpinLockRelease, sprintf, START_CRIT_SECTION, ReplicationSlotOnDisk::version, and write.

Referenced by CheckPointReplicationSlots(), CreateSlotOnDisk(), and ReplicationSlotSave().

◆ SearchNamedReplicationSlot()

ReplicationSlot* SearchNamedReplicationSlot ( const char *  name,
bool  need_lock 
)

Definition at line 464 of file slot.c.

465 {
466  int i;
467  ReplicationSlot *slot = NULL;
468 
469  if (need_lock)
470  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
471 
472  for (i = 0; i < max_replication_slots; i++)
473  {
475 
476  if (s->in_use && strcmp(name, NameStr(s->data.name)) == 0)
477  {
478  slot = s;
479  break;
480  }
481  }
482 
483  if (need_lock)
484  LWLockRelease(ReplicationSlotControlLock);
485 
486  return slot;
487 }

References ReplicationSlot::data, i, ReplicationSlot::in_use, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, name, ReplicationSlotPersistentData::name, NameStr, ReplicationSlotCtlData::replication_slots, and ReplicationSlotCtl.

Referenced by get_replslot_index(), pg_ls_replslotdir(), pgstat_reset_replslot(), ReadReplicationSlot(), ReplicationSlotAcquire(), StandbySlotsHaveCaughtup(), synchronize_one_slot(), and validate_standby_slots().

◆ SlotExistsInStandbySlotNames()

bool SlotExistsInStandbySlotNames ( const char *  slot_name)

Definition at line 2549 of file slot.c.

2550 {
2551  const char *standby_slot_name;
2552 
2553  /* Return false if there is no value in standby_slot_names */
2554  if (standby_slot_names_config == NULL)
2555  return false;
2556 
2557  /*
2558  * XXX: We are not expecting this list to be long so a linear search
2559  * shouldn't hurt but if that turns out not to be true then we can cache
2560  * this information for each WalSender as well.
2561  */
2562  standby_slot_name = standby_slot_names_config->slot_names;
2563  for (int i = 0; i < standby_slot_names_config->nslotnames; i++)
2564  {
2565  if (strcmp(standby_slot_name, slot_name) == 0)
2566  return true;
2567 
2568  standby_slot_name += strlen(standby_slot_name) + 1;
2569  }
2570 
2571  return false;
2572 }

References i, StandbySlotNamesConfigData::nslotnames, StandbySlotNamesConfigData::slot_names, and standby_slot_names_config.

Referenced by PhysicalWakeupLogicalWalSnd().

◆ StandbySlotsHaveCaughtup()

bool StandbySlotsHaveCaughtup ( XLogRecPtr  wait_for_lsn,
int  elevel 
)

Definition at line 2582 of file slot.c.

2583 {
2584  const char *name;
2585  int caught_up_slot_num = 0;
2586  XLogRecPtr min_restart_lsn = InvalidXLogRecPtr;
2587 
2588  /*
2589  * Don't need to wait for the standbys to catch up if there is no value in
2590  * standby_slot_names.
2591  */
2592  if (standby_slot_names_config == NULL)
2593  return true;
2594 
2595  /*
2596  * Don't need to wait for the standbys to catch up if we are on a standby
2597  * server, since we do not support syncing slots to cascading standbys.
2598  */
2599  if (RecoveryInProgress())
2600  return true;
2601 
2602  /*
2603  * Don't need to wait for the standbys to catch up if they are already
2604  * beyond the specified WAL location.
2605  */
2607  ss_oldest_flush_lsn >= wait_for_lsn)
2608  return true;
2609 
2610  /*
2611  * To prevent concurrent slot dropping and creation while filtering the
2612  * slots, take the ReplicationSlotControlLock outside of the loop.
2613  */
2614  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
2615 
2617  for (int i = 0; i < standby_slot_names_config->nslotnames; i++)
2618  {
2619  XLogRecPtr restart_lsn;
2620  bool invalidated;
2621  bool inactive;
2622  ReplicationSlot *slot;
2623 
2624  slot = SearchNamedReplicationSlot(name, false);
2625 
2626  if (!slot)
2627  {
2628  /*
2629  * If a slot name provided in standby_slot_names does not exist,
2630  * report a message and exit the loop. A user can specify a slot
2631  * name that does not exist just before the server startup. The
2632  * GUC check_hook(validate_standby_slots) cannot validate such a
2633  * slot during startup as the ReplicationSlotCtl shared memory is
2634  * not initialized at that time. It is also possible for a user to
2635  * drop the slot in standby_slot_names afterwards.
2636  */
2637  ereport(elevel,
2638  errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2639  errmsg("replication slot \"%s\" specified in parameter %s does not exist",
2640  name, "standby_slot_names"),
2641  errdetail("Logical replication is waiting on the standby associated with \"%s\".",
2642  name),
2643  errhint("Consider creating the slot \"%s\" or amend parameter %s.",
2644  name, "standby_slot_names"));
2645  break;
2646  }
2647 
2648  if (SlotIsLogical(slot))
2649  {
2650  /*
2651  * If a logical slot name is provided in standby_slot_names,
2652  * report a message and exit the loop. Similar to the non-existent
2653  * case, a user can specify a logical slot name in
2654  * standby_slot_names before the server startup, or drop an
2655  * existing physical slot and recreate a logical slot with the
2656  * same name.
2657  */
2658  ereport(elevel,
2659  errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2660  errmsg("cannot have logical replication slot \"%s\" in parameter %s",
2661  name, "standby_slot_names"),
2662  errdetail("Logical replication is waiting for correction on \"%s\".",
2663  name),
2664  errhint("Consider removing logical slot \"%s\" from parameter %s.",
2665  name, "standby_slot_names"));
2666  break;
2667  }
2668 
2669  SpinLockAcquire(&slot->mutex);
2670  restart_lsn = slot->data.restart_lsn;
2671  invalidated = slot->data.invalidated != RS_INVAL_NONE;
2672  inactive = slot->active_pid == 0;
2673  SpinLockRelease(&slot->mutex);
2674 
2675  if (invalidated)
2676  {
2677  /* Specified physical slot has been invalidated */
2678  ereport(elevel,
2679  errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
2680  errmsg("physical slot \"%s\" specified in parameter %s has been invalidated",
2681  name, "standby_slot_names"),
2682  errdetail("Logical replication is waiting on the standby associated with \"%s\".",
2683  name),
2684  errhint("Consider dropping and recreating the slot \"%s\" or amend parameter %s.",
2685  name, "standby_slot_names"));
2686  break;
2687  }
2688 
2689  if (XLogRecPtrIsInvalid(restart_lsn) || restart_lsn < wait_for_lsn)
2690  {
2691  /* Log a message if no active_pid for this physical slot */
2692  if (inactive)
2693  ereport(elevel,
2694  errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
2695  errmsg("replication slot \"%s\" specified in parameter %s does not have active_pid",
2696  name, "standby_slot_names"),
2697  errdetail("Logical replication is waiting on the standby associated with \"%s\".",
2698  name),
2699  errhint("Consider starting standby associated with \"%s\" or amend parameter %s.",
2700  name, "standby_slot_names"));
2701 
2702  /* Continue if the current slot hasn't caught up. */
2703  break;
2704  }
2705 
2706  Assert(restart_lsn >= wait_for_lsn);
2707 
2708  if (XLogRecPtrIsInvalid(min_restart_lsn) ||
2709  min_restart_lsn > restart_lsn)
2710  min_restart_lsn = restart_lsn;
2711 
2712  caught_up_slot_num++;
2713 
2714  name += strlen(name) + 1;
2715  }
2716 
2717  LWLockRelease(ReplicationSlotControlLock);
2718 
2719  /*
2720  * Return false if not all the standbys have caught up to the specified
2721  * WAL location.
2722  */
2723  if (caught_up_slot_num != standby_slot_names_config->nslotnames)
2724  return false;
2725 
2726  /* The ss_oldest_flush_lsn must not retreat. */
2728  min_restart_lsn >= ss_oldest_flush_lsn);
2729 
2730  ss_oldest_flush_lsn = min_restart_lsn;
2731 
2732  return true;
2733 }
#define XLogRecPtrIsInvalid(r)
Definition: xlogdefs.h:29

References ReplicationSlot::active_pid, Assert, ReplicationSlot::data, ereport, errcode(), errdetail(), errhint(), errmsg(), i, ReplicationSlotPersistentData::invalidated, InvalidXLogRecPtr, LW_SHARED, LWLockAcquire(), LWLockRelease(), ReplicationSlot::mutex, name, StandbySlotNamesConfigData::nslotnames, RecoveryInProgress(), ReplicationSlotPersistentData::restart_lsn, RS_INVAL_NONE, SearchNamedReplicationSlot(), StandbySlotNamesConfigData::slot_names, SlotIsLogical, SpinLockAcquire, SpinLockRelease, ss_oldest_flush_lsn, standby_slot_names_config, and XLogRecPtrIsInvalid.

Referenced by NeedToWaitForStandbys(), and WaitForStandbyConfirmation().

◆ StartupReplicationSlots()

void StartupReplicationSlots ( void  )

Definition at line 1898 of file slot.c.

1899 {
1900  DIR *replication_dir;
1901  struct dirent *replication_de;
1902 
1903  elog(DEBUG1, "starting up replication slots");
1904 
1905  /* restore all slots by iterating over all on-disk entries */
1906  replication_dir = AllocateDir("pg_replslot");
1907  while ((replication_de = ReadDir(replication_dir, "pg_replslot")) != NULL)
1908  {
1909  char path[MAXPGPATH + 12];
1910  PGFileType de_type;
1911 
1912  if (strcmp(replication_de->d_name, ".") == 0 ||
1913  strcmp(replication_de->d_name, "..") == 0)
1914  continue;
1915 
1916  snprintf(path, sizeof(path), "pg_replslot/%s", replication_de->d_name);
1917  de_type = get_dirent_type(path, replication_de, false, DEBUG1);
1918 
1919  /* we're only creating directories here, skip if it's not our's */
1920  if (de_type != PGFILETYPE_ERROR && de_type != PGFILETYPE_DIR)
1921  continue;
1922 
1923  /* we crashed while a slot was being setup or deleted, clean up */
1924  if (pg_str_endswith(replication_de->d_name, ".tmp"))
1925  {
1926  if (!rmtree(path, true))
1927  {
1928  ereport(WARNING,
1929  (errmsg("could not remove directory \"%s\"",
1930  path)));
1931  continue;
1932  }
1933  fsync_fname("pg_replslot", true);
1934  continue;
1935  }
1936 
1937  /* looks like a slot in a normal state, restore */
1938  RestoreSlotFromDisk(replication_de->d_name);
1939  }
1940  FreeDir(replication_dir);
1941 
1942  /* currently no slots exist, we're done. */
1943  if (max_replication_slots <= 0)
1944  return;
1945 
1946  /* Now that we have recovered all the data, compute replication xmin */
1949 }
struct dirent * ReadDir(DIR *dir, const char *dirname)
Definition: fd.c:2909
int FreeDir(DIR *dir)
Definition: fd.c:2961
DIR * AllocateDir(const char *dirname)
Definition: fd.c:2843
PGFileType get_dirent_type(const char *path, const struct dirent *de, bool look_through_symlinks, int elevel)
Definition: file_utils.c:525
PGFileType
Definition: file_utils.h:19
@ PGFILETYPE_DIR
Definition: file_utils.h:23
@ PGFILETYPE_ERROR
Definition: file_utils.h:20
#define snprintf
Definition: port.h:238
static void RestoreSlotFromDisk(const char *name)
Definition: slot.c:2175
bool pg_str_endswith(const char *str, const char *end)
Definition: string.c:32
Definition: dirent.c:26
Definition: dirent.h:10
char d_name[MAX_PATH]
Definition: dirent.h:15

References AllocateDir(), dirent::d_name, DEBUG1, elog, ereport, errmsg(), FreeDir(), fsync_fname(), get_dirent_type(), max_replication_slots, MAXPGPATH, pg_str_endswith(), PGFILETYPE_DIR, PGFILETYPE_ERROR, ReadDir(), ReplicationSlotsComputeRequiredLSN(), ReplicationSlotsComputeRequiredXmin(), RestoreSlotFromDisk(), rmtree(), snprintf, and WARNING.

Referenced by StartupXLOG().

◆ StaticAssertDecl()

StaticAssertDecl ( lengthof(SlotInvalidationCauses = =(RS_INVAL_MAX_CAUSES+1),
"array length mismatch"   
)

◆ validate_standby_slots()

static bool validate_standby_slots ( char *  rawname,
List **  elemlist 
)
static

Definition at line 2422 of file slot.c.

2423 {
2424  bool ok;
2425 
2426  /* Verify syntax and parse string into a list of identifiers */
2427  ok = SplitIdentifierString(rawname, ',', elemlist);
2428 
2429  if (!ok)
2430  {
2431  GUC_check_errdetail("List syntax is invalid.");
2432  }
2433  else if (!ReplicationSlotCtl)
2434  {
2435  /*
2436  * We cannot validate the replication slot if the replication slots'
2437  * data has not been initialized. This is ok as we will anyway
2438  * validate the specified slot when waiting for them to catch up. See
2439  * StandbySlotsHaveCaughtup() for details.
2440  */
2441  }
2442  else
2443  {
2444  /* Check that the specified slots exist and are logical slots */
2445  LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
2446 
2447  foreach_ptr(char, name, *elemlist)
2448  {
2449  ReplicationSlot *slot;
2450 
2451  slot = SearchNamedReplicationSlot(name, false);
2452 
2453  if (!slot)
2454  {
2455  GUC_check_errdetail("replication slot \"%s\" does not exist",
2456  name);
2457  ok = false;
2458  break;
2459  }
2460 
2461  if (!SlotIsPhysical(slot))
2462  {
2463  GUC_check_errdetail("\"%s\" is not a physical replication slot",
2464  name);
2465  ok = false;
2466  break;
2467  }
2468  }
2469 
2470  LWLockRelease(ReplicationSlotControlLock);
2471  }
2472 
2473  return ok;
2474 }
#define GUC_check_errdetail
Definition: guc.h:447
bool SplitIdentifierString(char *rawstring, char separator, List **namelist)
Definition: varlena.c:3457

References foreach_ptr, GUC_check_errdetail, LW_SHARED, LWLockAcquire(), LWLockRelease(), name, ReplicationSlotCtl, SearchNamedReplicationSlot(), SlotIsPhysical, and SplitIdentifierString().

Referenced by check_standby_slot_names().

◆ WaitForStandbyConfirmation()

void WaitForStandbyConfirmation ( XLogRecPtr  wait_for_lsn)

Definition at line 2742 of file slot.c.

2743 {
2744  /*
2745  * Don't need to wait for the standby to catch up if the current acquired
2746  * slot is not a logical failover slot, or there is no value in
2747  * standby_slot_names.
2748  */
2750  return;
2751 
2753 
2754  for (;;)
2755  {
2757 
2758  if (ConfigReloadPending)
2759  {
2760  ConfigReloadPending = false;
2762  }
2763 
2764  /* Exit if done waiting for every slot. */
2765  if (StandbySlotsHaveCaughtup(wait_for_lsn, WARNING))
2766  break;
2767 
2768  /*
2769  * Wait for the slots in the standby_slot_names to catch up, but use a
2770  * timeout (1s) so we can also check if the standby_slot_names has
2771  * been changed.
2772  */
2774  WAIT_EVENT_WAIT_FOR_STANDBY_CONFIRMATION);
2775  }
2776 
2778 }
bool ConditionVariableTimedSleep(ConditionVariable *cv, long timeout, uint32 wait_event_info)
@ PGC_SIGHUP
Definition: guc.h:71
void ProcessConfigFile(GucContext context)
volatile sig_atomic_t ConfigReloadPending
Definition: interrupt.c:27
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:122
bool StandbySlotsHaveCaughtup(XLogRecPtr wait_for_lsn, int elevel)
Definition: slot.c:2582
ConditionVariable wal_confirm_rcv_cv
WalSndCtlData * WalSndCtl
Definition: walsender.c:109

References CHECK_FOR_INTERRUPTS, ConditionVariableCancelSleep(), ConditionVariablePrepareToSleep(), ConditionVariableTimedSleep(), ConfigReloadPending, ReplicationSlot::data, ReplicationSlotPersistentData::failover, MyReplicationSlot, PGC_SIGHUP, ProcessConfigFile(), standby_slot_names_config, StandbySlotsHaveCaughtup(), WalSndCtlData::wal_confirm_rcv_cv, WalSndCtl, and WARNING.

Referenced by LogicalSlotAdvanceAndCheckSnapState(), and pg_logical_slot_get_changes_guts().

Variable Documentation

◆ max_replication_slots

◆ MyReplicationSlot

ReplicationSlot* MyReplicationSlot = NULL

Definition at line 138 of file slot.c.

Referenced by binary_upgrade_logical_slot_has_caught_up(), copy_replication_slot(), create_logical_replication_slot(), create_physical_replication_slot(), CreateDecodingContext(), CreateInitDecodingContext(), CreateReplicationSlot(), InvalidatePossiblyObsoleteSlot(), LogicalConfirmReceivedLocation(), LogicalIncreaseRestartDecodingForSlot(), LogicalIncreaseXminForSlot(), LogicalReplicationSlotHasPendingWal(), LogicalSlotAdvanceAndCheckSnapState(), NeedToWaitForStandbys(), pg_create_logical_replication_slot(), pg_create_physical_replication_slot(), pg_logical_slot_get_changes_guts(), pg_physical_replication_slot_advance(), pg_replication_slot_advance(), PhysicalConfirmReceivedLocation(), PhysicalReplicationSlotNewXmin(), PhysicalWakeupLogicalWalSnd(), PostgresMain(), ProcessStandbyHSFeedbackMessage(), ProcessStandbyReplyMessage(), ReorderBufferAllocate(), ReorderBufferFree(), ReorderBufferRestoreChanges(), ReorderBufferRestoreCleanup(), ReorderBufferSerializedPath(), ReorderBufferSerializeTXN(), ReplicationSlotAcquire(), ReplicationSlotAlter(), ReplicationSlotCleanup(), ReplicationSlotCreate(), ReplicationSlotDrop(), ReplicationSlotDropAcquired(), ReplicationSlotMarkDirty(), ReplicationSlotPersist(), ReplicationSlotRelease(), ReplicationSlotReserveWal(), ReplicationSlotSave(), ReplicationSlotsDropDBSlots(), ReplicationSlotShmemExit(), reserve_wal_for_local_slot(), slotsync_failure_callback(), slotsync_worker_onexit(), StartLogicalReplication(), StartReplication(), StartupDecodingContext(), synchronize_one_slot(), update_and_persist_local_synced_slot(), update_local_synced_slot(), WaitForStandbyConfirmation(), and WalSndErrorCleanup().

◆ ReplicationSlotCtl

◆ SlotInvalidationCauses

const char* const SlotInvalidationCauses[]
Initial value:
= {
[RS_INVAL_NONE] = "none",
[RS_INVAL_WAL_REMOVED] = "wal_removed",
[RS_INVAL_HORIZON] = "rows_removed",
[RS_INVAL_WAL_LEVEL] = "wal_level_insufficient",
}

Definition at line 105 of file slot.c.

Referenced by GetSlotInvalidationCause(), and pg_get_replication_slots().

◆ ss_oldest_flush_lsn

XLogRecPtr ss_oldest_flush_lsn = InvalidXLogRecPtr
static

Definition at line 157 of file slot.c.

Referenced by assign_standby_slot_names(), and StandbySlotsHaveCaughtup().

◆ standby_slot_names

char* standby_slot_names

Definition at line 148 of file slot.c.

◆ standby_slot_names_config