xlogfuncs.c File Reference

#include "postgres.h"
#include <unistd.h>
#include "access/htup_details.h"
#include "access/xlog_internal.h"
#include "access/xlogbackup.h"
#include "access/xlogrecovery.h"
#include "catalog/pg_type.h"
#include "commands/waitlsn.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "replication/walreceiver.h"
#include "storage/fd.h"
#include "storage/proc.h"
#include "storage/standby.h"
#include "utils/builtins.h"
#include "utils/memutils.h"
#include "utils/pg_lsn.h"
#include "utils/snapmgr.h"
#include "utils/timestamp.h"

Include dependency graph for xlogfuncs.c:

Go to the source code of this file.

Macros
#define	PG_BACKUP_STOP_V2_COLS   3
#define	PG_SPLIT_WALFILE_NAME_COLS   2
#define	WAITS_PER_SECOND   10

Functions
Datum	pg_backup_start (PG_FUNCTION_ARGS)
Datum	pg_backup_stop (PG_FUNCTION_ARGS)
Datum	pg_switch_wal (PG_FUNCTION_ARGS)
Datum	pg_log_standby_snapshot (PG_FUNCTION_ARGS)
Datum	pg_create_restore_point (PG_FUNCTION_ARGS)
Datum	pg_current_wal_lsn (PG_FUNCTION_ARGS)
Datum	pg_current_wal_insert_lsn (PG_FUNCTION_ARGS)
Datum	pg_current_wal_flush_lsn (PG_FUNCTION_ARGS)
Datum	pg_last_wal_receive_lsn (PG_FUNCTION_ARGS)
Datum	pg_last_wal_replay_lsn (PG_FUNCTION_ARGS)
Datum	pg_walfile_name_offset (PG_FUNCTION_ARGS)
Datum	pg_walfile_name (PG_FUNCTION_ARGS)
Datum	pg_split_walfile_name (PG_FUNCTION_ARGS)
Datum	pg_wal_replay_pause (PG_FUNCTION_ARGS)
Datum	pg_wal_replay_resume (PG_FUNCTION_ARGS)
Datum	pg_is_wal_replay_paused (PG_FUNCTION_ARGS)
Datum	pg_get_wal_replay_pause_state (PG_FUNCTION_ARGS)
Datum	pg_last_xact_replay_timestamp (PG_FUNCTION_ARGS)
Datum	pg_is_in_recovery (PG_FUNCTION_ARGS)
Datum	pg_wal_lsn_diff (PG_FUNCTION_ARGS)
Datum	pg_promote (PG_FUNCTION_ARGS)
Datum	pg_wal_replay_wait (PG_FUNCTION_ARGS)

Variables
static BackupState *	backup_state = NULL
static StringInfo	tablespace_map = NULL
static MemoryContext	backupcontext = NULL

Macro Definition Documentation

PG_BACKUP_STOP_V2_COLS

#define PG_BACKUP_STOP_V2_COLS   3

PG_SPLIT_WALFILE_NAME_COLS

#define PG_SPLIT_WALFILE_NAME_COLS   2

WAITS_PER_SECOND

#define WAITS_PER_SECOND   10

Function Documentation

pg_backup_start()

Datum pg_backup_start

(

PG_FUNCTION_ARGS

)

Definition at line 59 of file xlogfuncs.c.

{
    text       *backupid = PG_GETARG_TEXT_PP(0);
    bool        fast = PG_GETARG_BOOL(1);
    char       *backupidstr;
    SessionBackupState status = get_backup_status();
    MemoryContext oldcontext;
 
    backupidstr = text_to_cstring(backupid);
 
    if (status == SESSION_BACKUP_RUNNING)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("a backup is already in progress in this session")));
 
    /*
     * backup_state and tablespace_map need to be long-lived as they are used
     * in pg_backup_stop().  These are allocated in a dedicated memory context
     * child of TopMemoryContext, deleted at the end of pg_backup_stop().  If
     * an error happens before ending the backup, memory would be leaked in
     * this context until pg_backup_start() is called again.
     */
    if (backupcontext == NULL)
    {
        backupcontext = AllocSetContextCreate(TopMemoryContext,
                                              "on-line backup context",
                                              ALLOCSET_START_SMALL_SIZES);
    }
    else
    {
        backup_state = NULL;
        tablespace_map = NULL;
        MemoryContextReset(backupcontext);
    }
 
    oldcontext = MemoryContextSwitchTo(backupcontext);
    backup_state = (BackupState *) palloc0(sizeof(BackupState));
    tablespace_map = makeStringInfo();
    MemoryContextSwitchTo(oldcontext);
 
    register_persistent_abort_backup_handler();
    do_pg_backup_start(backupidstr, fast, NULL, backup_state, tablespace_map);
 
    PG_RETURN_LSN(backup_state->startpoint);
}

References ALLOCSET_START_SMALL_SIZES, AllocSetContextCreate, backup_state, backupcontext, do_pg_backup_start(), ereport, errcode(), errmsg(), ERROR, get_backup_status(), makeStringInfo(), MemoryContextReset(), MemoryContextSwitchTo(), palloc0(), PG_GETARG_BOOL, PG_GETARG_TEXT_PP, PG_RETURN_LSN, register_persistent_abort_backup_handler(), SESSION_BACKUP_RUNNING, BackupState::startpoint, tablespace_map, text_to_cstring(), and TopMemoryContext.

pg_backup_stop()

Datum pg_backup_stop

(

PG_FUNCTION_ARGS

)

Definition at line 126 of file xlogfuncs.c.

{
#define PG_BACKUP_STOP_V2_COLS 3
    TupleDesc   tupdesc;
    Datum       values[PG_BACKUP_STOP_V2_COLS] = {0};
    bool        nulls[PG_BACKUP_STOP_V2_COLS] = {0};
    bool        waitforarchive = PG_GETARG_BOOL(0);
    char       *backup_label;
    SessionBackupState status = get_backup_status();
 
    /* Initialize attributes information in the tuple descriptor */
    if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
        elog(ERROR, "return type must be a row type");
 
    if (status != SESSION_BACKUP_RUNNING)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("backup is not in progress"),
                 errhint("Did you call pg_backup_start()?")));
 
    Assert(backup_state != NULL);
    Assert(tablespace_map != NULL);
 
    /* Stop the backup */
    do_pg_backup_stop(backup_state, waitforarchive);
 
    /* Build the contents of backup_label */
    backup_label = build_backup_content(backup_state, false);
 
    values[0] = LSNGetDatum(backup_state->stoppoint);
    values[1] = CStringGetTextDatum(backup_label);
    values[2] = CStringGetTextDatum(tablespace_map->data);
 
    /* Deallocate backup-related variables */
    pfree(backup_label);
 
    /* Clean up the session-level state and its memory context */
    backup_state = NULL;
    tablespace_map = NULL;
    MemoryContextDelete(backupcontext);
    backupcontext = NULL;
 
    /* Returns the record as Datum */
    PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
}

References Assert, backup_state, backupcontext, build_backup_content(), CStringGetTextDatum, StringInfoData::data, do_pg_backup_stop(), elog, ereport, errcode(), errhint(), errmsg(), ERROR, get_backup_status(), get_call_result_type(), heap_form_tuple(), HeapTupleGetDatum(), LSNGetDatum(), MemoryContextDelete(), pfree(), PG_BACKUP_STOP_V2_COLS, PG_GETARG_BOOL, PG_RETURN_DATUM, SESSION_BACKUP_RUNNING, BackupState::stoppoint, tablespace_map, TYPEFUNC_COMPOSITE, and values.

pg_create_restore_point()

Datum pg_create_restore_point

(

PG_FUNCTION_ARGS

)

Definition at line 235 of file xlogfuncs.c.

{
    text       *restore_name = PG_GETARG_TEXT_PP(0);
    char       *restore_name_str;
    XLogRecPtr  restorepoint;
 
    if (RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("recovery is in progress"),
                 errhint("WAL control functions cannot be executed during recovery.")));
 
    if (!XLogIsNeeded())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("WAL level not sufficient for creating a restore point"),
                 errhint("\"wal_level\" must be set to \"replica\" or \"logical\" at server start.")));
 
    restore_name_str = text_to_cstring(restore_name);
 
    if (strlen(restore_name_str) >= MAXFNAMELEN)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("value too long for restore point (maximum %d characters)", MAXFNAMELEN - 1)));
 
    restorepoint = XLogRestorePoint(restore_name_str);
 
    /*
     * As a convenience, return the WAL location of the restore point record
     */
    PG_RETURN_LSN(restorepoint);
}

References ereport, errcode(), errhint(), errmsg(), ERROR, MAXFNAMELEN, PG_GETARG_TEXT_PP, PG_RETURN_LSN, RecoveryInProgress(), text_to_cstring(), XLogIsNeeded, and XLogRestorePoint().

pg_current_wal_flush_lsn()

Datum pg_current_wal_flush_lsn

(

PG_FUNCTION_ARGS

)

Definition at line 318 of file xlogfuncs.c.

{
    XLogRecPtr  current_recptr;
 
    if (RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("recovery is in progress"),
                 errhint("WAL control functions cannot be executed during recovery.")));
 
    current_recptr = GetFlushRecPtr(NULL);
 
    PG_RETURN_LSN(current_recptr);
}

References ereport, errcode(), errhint(), errmsg(), ERROR, GetFlushRecPtr(), PG_RETURN_LSN, and RecoveryInProgress().

pg_current_wal_insert_lsn()

Datum pg_current_wal_insert_lsn

(

PG_FUNCTION_ARGS

)

Definition at line 297 of file xlogfuncs.c.

{
    XLogRecPtr  current_recptr;
 
    if (RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("recovery is in progress"),
                 errhint("WAL control functions cannot be executed during recovery.")));
 
    current_recptr = GetXLogInsertRecPtr();
 
    PG_RETURN_LSN(current_recptr);
}

References ereport, errcode(), errhint(), errmsg(), ERROR, GetXLogInsertRecPtr(), PG_RETURN_LSN, and RecoveryInProgress().

pg_current_wal_lsn()

Datum pg_current_wal_lsn

(

PG_FUNCTION_ARGS

)

Definition at line 276 of file xlogfuncs.c.

{
    XLogRecPtr  current_recptr;
 
    if (RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("recovery is in progress"),
                 errhint("WAL control functions cannot be executed during recovery.")));
 
    current_recptr = GetXLogWriteRecPtr();
 
    PG_RETURN_LSN(current_recptr);
}

References ereport, errcode(), errhint(), errmsg(), ERROR, GetXLogWriteRecPtr(), PG_RETURN_LSN, and RecoveryInProgress().

pg_get_wal_replay_pause_state()

Datum pg_get_wal_replay_pause_state

(

PG_FUNCTION_ARGS

)

Definition at line 595 of file xlogfuncs.c.

{
    char       *statestr = NULL;
 
    if (!RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("recovery is not in progress"),
                 errhint("Recovery control functions can only be executed during recovery.")));
 
    /* get the recovery pause state */
    switch (GetRecoveryPauseState())
    {
        case RECOVERY_NOT_PAUSED:
            statestr = "not paused";
            break;
        case RECOVERY_PAUSE_REQUESTED:
            statestr = "pause requested";
            break;
        case RECOVERY_PAUSED:
            statestr = "paused";
            break;
    }
 
    Assert(statestr != NULL);
    PG_RETURN_TEXT_P(cstring_to_text(statestr));
}

References Assert, cstring_to_text(), ereport, errcode(), errhint(), errmsg(), ERROR, GetRecoveryPauseState(), PG_RETURN_TEXT_P, RECOVERY_NOT_PAUSED, RECOVERY_PAUSE_REQUESTED, RECOVERY_PAUSED, and RecoveryInProgress().

pg_is_in_recovery()

Datum pg_is_in_recovery

(

PG_FUNCTION_ARGS

)

Definition at line 645 of file xlogfuncs.c.

{
    PG_RETURN_BOOL(RecoveryInProgress());
}

References PG_RETURN_BOOL, and RecoveryInProgress().

pg_is_wal_replay_paused()

Datum pg_is_wal_replay_paused

(

PG_FUNCTION_ARGS

)

Definition at line 574 of file xlogfuncs.c.

{
    if (!RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("recovery is not in progress"),
                 errhint("Recovery control functions can only be executed during recovery.")));
 
    PG_RETURN_BOOL(GetRecoveryPauseState() != RECOVERY_NOT_PAUSED);
}

References ereport, errcode(), errhint(), errmsg(), ERROR, GetRecoveryPauseState(), PG_RETURN_BOOL, RECOVERY_NOT_PAUSED, and RecoveryInProgress().

pg_last_wal_receive_lsn()

Datum pg_last_wal_receive_lsn

(

PG_FUNCTION_ARGS

)

Definition at line 340 of file xlogfuncs.c.

{
    XLogRecPtr  recptr;
 
    recptr = GetWalRcvFlushRecPtr(NULL, NULL);
 
    if (recptr == 0)
        PG_RETURN_NULL();
 
    PG_RETURN_LSN(recptr);
}

References GetWalRcvFlushRecPtr(), PG_RETURN_LSN, and PG_RETURN_NULL.

pg_last_wal_replay_lsn()

Datum pg_last_wal_replay_lsn

(

PG_FUNCTION_ARGS

)

Definition at line 359 of file xlogfuncs.c.

{
    XLogRecPtr  recptr;
 
    recptr = GetXLogReplayRecPtr(NULL);
 
    if (recptr == 0)
        PG_RETURN_NULL();
 
    PG_RETURN_LSN(recptr);
}

References GetXLogReplayRecPtr(), PG_RETURN_LSN, and PG_RETURN_NULL.

pg_last_xact_replay_timestamp()

Datum pg_last_xact_replay_timestamp

(

PG_FUNCTION_ARGS

)

Definition at line 630 of file xlogfuncs.c.

{
    TimestampTz xtime;
 
    xtime = GetLatestXTime();
    if (xtime == 0)
        PG_RETURN_NULL();
 
    PG_RETURN_TIMESTAMPTZ(xtime);
}

References GetLatestXTime(), PG_RETURN_NULL, and PG_RETURN_TIMESTAMPTZ.

pg_log_standby_snapshot()

Datum pg_log_standby_snapshot

(

PG_FUNCTION_ARGS

)

Definition at line 204 of file xlogfuncs.c.

{
    XLogRecPtr  recptr;
 
    if (RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("recovery is in progress"),
                 errhint("%s cannot be executed during recovery.",
                         "pg_log_standby_snapshot()")));
 
    if (!XLogStandbyInfoActive())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("pg_log_standby_snapshot() can only be used if \"wal_level\" >= \"replica\"")));
 
    recptr = LogStandbySnapshot();
 
    /*
     * As a convenience, return the WAL location of the last inserted record
     */
    PG_RETURN_LSN(recptr);
}

References ereport, errcode(), errhint(), errmsg(), ERROR, LogStandbySnapshot(), PG_RETURN_LSN, RecoveryInProgress(), and XLogStandbyInfoActive.

pg_promote()

Datum pg_promote

(

PG_FUNCTION_ARGS

)

Definition at line 672 of file xlogfuncs.c.

{
    bool        wait = PG_GETARG_BOOL(0);
    int         wait_seconds = PG_GETARG_INT32(1);
    FILE       *promote_file;
    int         i;
 
    if (!RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("recovery is not in progress"),
                 errhint("Recovery control functions can only be executed during recovery.")));
 
    if (wait_seconds <= 0)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("\"wait_seconds\" must not be negative or zero")));
 
    /* create the promote signal file */
    promote_file = AllocateFile(PROMOTE_SIGNAL_FILE, "w");
    if (!promote_file)
        ereport(ERROR,
                (errcode_for_file_access(),
                 errmsg("could not create file \"%s\": %m",
                        PROMOTE_SIGNAL_FILE)));
 
    if (FreeFile(promote_file))
        ereport(ERROR,
                (errcode_for_file_access(),
                 errmsg("could not write file \"%s\": %m",
                        PROMOTE_SIGNAL_FILE)));
 
    /* signal the postmaster */
    if (kill(PostmasterPid, SIGUSR1) != 0)
    {
        (void) unlink(PROMOTE_SIGNAL_FILE);
        ereport(ERROR,
                (errcode(ERRCODE_SYSTEM_ERROR),
                 errmsg("failed to send signal to postmaster: %m")));
    }
 
    /* return immediately if waiting was not requested */
    if (!wait)
        PG_RETURN_BOOL(true);
 
    /* wait for the amount of time wanted until promotion */
#define WAITS_PER_SECOND 10
    for (i = 0; i < WAITS_PER_SECOND * wait_seconds; i++)
    {
        int         rc;
 
        ResetLatch(MyLatch);
 
        if (!RecoveryInProgress())
            PG_RETURN_BOOL(true);
 
        CHECK_FOR_INTERRUPTS();
 
        rc = WaitLatch(MyLatch,
                       WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
                       1000L / WAITS_PER_SECOND,
                       WAIT_EVENT_PROMOTE);
 
        /*
         * Emergency bailout if postmaster has died.  This is to avoid the
         * necessity for manual cleanup of all postmaster children.
         */
        if (rc & WL_POSTMASTER_DEATH)
            ereport(FATAL,
                    (errcode(ERRCODE_ADMIN_SHUTDOWN),
                     errmsg("terminating connection due to unexpected postmaster exit"),
                     errcontext("while waiting on promotion")));
    }
 
    ereport(WARNING,
            (errmsg_plural("server did not promote within %d second",
                           "server did not promote within %d seconds",
                           wait_seconds,
                           wait_seconds)));
    PG_RETURN_BOOL(false);
}

References AllocateFile(), CHECK_FOR_INTERRUPTS, ereport, errcode(), errcode_for_file_access(), errcontext, errhint(), errmsg(), errmsg_plural(), ERROR, FATAL, FreeFile(), i, kill, MyLatch, PG_GETARG_BOOL, PG_GETARG_INT32, PG_RETURN_BOOL, PostmasterPid, promote_file, PROMOTE_SIGNAL_FILE, RecoveryInProgress(), ResetLatch(), SIGUSR1, wait_seconds, WaitLatch(), WAITS_PER_SECOND, WARNING, WL_LATCH_SET, WL_POSTMASTER_DEATH, and WL_TIMEOUT.

pg_split_walfile_name()

Datum pg_split_walfile_name

(

PG_FUNCTION_ARGS

)

Definition at line 465 of file xlogfuncs.c.

{
#define PG_SPLIT_WALFILE_NAME_COLS 2
    char       *fname = text_to_cstring(PG_GETARG_TEXT_PP(0));
    char       *fname_upper;
    char       *p;
    TimeLineID  tli;
    XLogSegNo   segno;
    Datum       values[PG_SPLIT_WALFILE_NAME_COLS] = {0};
    bool        isnull[PG_SPLIT_WALFILE_NAME_COLS] = {0};
    TupleDesc   tupdesc;
    HeapTuple   tuple;
    char        buf[256];
    Datum       result;
 
    fname_upper = pstrdup(fname);
 
    /* Capitalize WAL file name. */
    for (p = fname_upper; *p; p++)
        *p = pg_toupper((unsigned char) *p);
 
    if (!IsXLogFileName(fname_upper))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("invalid WAL file name \"%s\"", fname)));
 
    XLogFromFileName(fname_upper, &tli, &segno, wal_segment_size);
 
    if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
        elog(ERROR, "return type must be a row type");
 
    /* Convert to numeric. */
    snprintf(buf, sizeof buf, UINT64_FORMAT, segno);
    values[0] = DirectFunctionCall3(numeric_in,
                                    CStringGetDatum(buf),
                                    ObjectIdGetDatum(0),
                                    Int32GetDatum(-1));
 
    values[1] = Int64GetDatum(tli);
 
    tuple = heap_form_tuple(tupdesc, values, isnull);
    result = HeapTupleGetDatum(tuple);
 
    PG_RETURN_DATUM(result);
 
#undef PG_SPLIT_WALFILE_NAME_COLS
}

References buf, CStringGetDatum(), DirectFunctionCall3, elog, ereport, errcode(), errmsg(), ERROR, get_call_result_type(), heap_form_tuple(), HeapTupleGetDatum(), Int32GetDatum(), Int64GetDatum(), IsXLogFileName(), numeric_in(), ObjectIdGetDatum(), PG_GETARG_TEXT_PP, PG_RETURN_DATUM, PG_SPLIT_WALFILE_NAME_COLS, pg_toupper(), pstrdup(), snprintf, text_to_cstring(), TYPEFUNC_COMPOSITE, UINT64_FORMAT, values, wal_segment_size, and XLogFromFileName().

pg_switch_wal()

Datum pg_switch_wal

(

PG_FUNCTION_ARGS

)

Definition at line 179 of file xlogfuncs.c.

{
    XLogRecPtr  switchpoint;
 
    if (RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("recovery is in progress"),
                 errhint("WAL control functions cannot be executed during recovery.")));
 
    switchpoint = RequestXLogSwitch(false);
 
    /*
     * As a convenience, return the WAL location of the switch record
     */
    PG_RETURN_LSN(switchpoint);
}

References ereport, errcode(), errhint(), errmsg(), ERROR, PG_RETURN_LSN, RecoveryInProgress(), and RequestXLogSwitch().

pg_wal_lsn_diff()

Datum pg_wal_lsn_diff

(

PG_FUNCTION_ARGS

)

Definition at line 654 of file xlogfuncs.c.

{
    Datum       result;
 
    result = DirectFunctionCall2(pg_lsn_mi,
                                 PG_GETARG_DATUM(0),
                                 PG_GETARG_DATUM(1));
 
    PG_RETURN_DATUM(result);
}

References DirectFunctionCall2, PG_GETARG_DATUM, pg_lsn_mi(), and PG_RETURN_DATUM.

pg_wal_replay_pause()

Datum pg_wal_replay_pause

(

PG_FUNCTION_ARGS

)

Definition at line 520 of file xlogfuncs.c.

{
    if (!RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("recovery is not in progress"),
                 errhint("Recovery control functions can only be executed during recovery.")));
 
    if (PromoteIsTriggered())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("standby promotion is ongoing"),
                 errhint("%s cannot be executed after promotion is triggered.",
                         "pg_wal_replay_pause()")));
 
    SetRecoveryPause(true);
 
    /* wake up the recovery process so that it can process the pause request */
    WakeupRecovery();
 
    PG_RETURN_VOID();
}

References ereport, errcode(), errhint(), errmsg(), ERROR, PG_RETURN_VOID, PromoteIsTriggered(), RecoveryInProgress(), SetRecoveryPause(), and WakeupRecovery().

pg_wal_replay_resume()

Datum pg_wal_replay_resume

(

PG_FUNCTION_ARGS

)

Definition at line 550 of file xlogfuncs.c.

{
    if (!RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("recovery is not in progress"),
                 errhint("Recovery control functions can only be executed during recovery.")));
 
    if (PromoteIsTriggered())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("standby promotion is ongoing"),
                 errhint("%s cannot be executed after promotion is triggered.",
                         "pg_wal_replay_resume()")));
 
    SetRecoveryPause(false);
 
    PG_RETURN_VOID();
}

References ereport, errcode(), errhint(), errmsg(), ERROR, PG_RETURN_VOID, PromoteIsTriggered(), RecoveryInProgress(), and SetRecoveryPause().

pg_wal_replay_wait()

Datum pg_wal_replay_wait

(

PG_FUNCTION_ARGS

)

Definition at line 758 of file xlogfuncs.c.

{
    XLogRecPtr  target_lsn = PG_GETARG_LSN(0);
    int64       timeout = PG_GETARG_INT64(1);
 
    if (timeout < 0)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("\"timeout\" must not be negative")));
 
    /*
     * We are going to wait for the LSN replay.  We should first care that we
     * don't hold a snapshot and correspondingly our MyProc->xmin is invalid.
     * Otherwise, our snapshot could prevent the replay of WAL records
     * implying a kind of self-deadlock.  This is the reason why
     * pg_wal_replay_wait() is a procedure, not a function.
     *
     * At first, we should check there is no active snapshot.  According to
     * PlannedStmtRequiresSnapshot(), even in an atomic context, CallStmt is
     * processed with a snapshot.  Thankfully, we can pop this snapshot,
     * because PortalRunUtility() can tolerate this.
     */
    if (ActiveSnapshotSet())
        PopActiveSnapshot();
 
    /*
     * At second, invalidate a catalog snapshot if any.  And we should be done
     * with the preparation.
     */
    InvalidateCatalogSnapshot();
 
    /* Give up if there is still an active or registered snapshot. */
    if (GetOldestSnapshot())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("pg_wal_replay_wait() must be only called without an active or registered snapshot"),
                 errdetail("Make sure pg_wal_replay_wait() isn't called within a transaction with an isolation level higher than READ COMMITTED, another procedure, or a function.")));
 
    /*
     * As the result we should hold no snapshot, and correspondingly our xmin
     * should be unset.
     */
    Assert(MyProc->xmin == InvalidTransactionId);
 
    (void) WaitForLSNReplay(target_lsn, timeout);
 
    PG_RETURN_VOID();
}

References ActiveSnapshotSet(), Assert, ereport, errcode(), errdetail(), errmsg(), ERROR, GetOldestSnapshot(), InvalidateCatalogSnapshot(), InvalidTransactionId, MyProc, PG_GETARG_INT64, PG_GETARG_LSN, PG_RETURN_VOID, PopActiveSnapshot(), WaitForLSNReplay(), and PGPROC::xmin.

pg_walfile_name()

Datum pg_walfile_name

(

PG_FUNCTION_ARGS

)

Definition at line 440 of file xlogfuncs.c.

{
    XLogSegNo   xlogsegno;
    XLogRecPtr  locationpoint = PG_GETARG_LSN(0);
    char        xlogfilename[MAXFNAMELEN];
 
    if (RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("recovery is in progress"),
                 errhint("%s cannot be executed during recovery.",
                         "pg_walfile_name()")));
 
    XLByteToSeg(locationpoint, xlogsegno, wal_segment_size);
    XLogFileName(xlogfilename, GetWALInsertionTimeLine(), xlogsegno,
                 wal_segment_size);
 
    PG_RETURN_TEXT_P(cstring_to_text(xlogfilename));
}

References cstring_to_text(), ereport, errcode(), errhint(), errmsg(), ERROR, GetWALInsertionTimeLine(), MAXFNAMELEN, PG_GETARG_LSN, PG_RETURN_TEXT_P, RecoveryInProgress(), wal_segment_size, XLByteToSeg, and XLogFileName().

pg_walfile_name_offset()

Datum pg_walfile_name_offset

(

PG_FUNCTION_ARGS

)

Definition at line 376 of file xlogfuncs.c.

{
    XLogSegNo   xlogsegno;
    uint32      xrecoff;
    XLogRecPtr  locationpoint = PG_GETARG_LSN(0);
    char        xlogfilename[MAXFNAMELEN];
    Datum       values[2];
    bool        isnull[2];
    TupleDesc   resultTupleDesc;
    HeapTuple   resultHeapTuple;
    Datum       result;
 
    if (RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("recovery is in progress"),
                 errhint("%s cannot be executed during recovery.",
                         "pg_walfile_name_offset()")));
 
    /*
     * Construct a tuple descriptor for the result row.  This must match this
     * function's pg_proc entry!
     */
    resultTupleDesc = CreateTemplateTupleDesc(2);
    TupleDescInitEntry(resultTupleDesc, (AttrNumber) 1, "file_name",
                       TEXTOID, -1, 0);
    TupleDescInitEntry(resultTupleDesc, (AttrNumber) 2, "file_offset",
                       INT4OID, -1, 0);
 
    resultTupleDesc = BlessTupleDesc(resultTupleDesc);
 
    /*
     * xlogfilename
     */
    XLByteToSeg(locationpoint, xlogsegno, wal_segment_size);
    XLogFileName(xlogfilename, GetWALInsertionTimeLine(), xlogsegno,
                 wal_segment_size);
 
    values[0] = CStringGetTextDatum(xlogfilename);
    isnull[0] = false;
 
    /*
     * offset
     */
    xrecoff = XLogSegmentOffset(locationpoint, wal_segment_size);
 
    values[1] = UInt32GetDatum(xrecoff);
    isnull[1] = false;
 
    /*
     * Tuple jam: Having first prepared your Datums, then squash together
     */
    resultHeapTuple = heap_form_tuple(resultTupleDesc, values, isnull);
 
    result = HeapTupleGetDatum(resultHeapTuple);
 
    PG_RETURN_DATUM(result);
}

References BlessTupleDesc(), CreateTemplateTupleDesc(), CStringGetTextDatum, ereport, errcode(), errhint(), errmsg(), ERROR, GetWALInsertionTimeLine(), heap_form_tuple(), HeapTupleGetDatum(), MAXFNAMELEN, PG_GETARG_LSN, PG_RETURN_DATUM, RecoveryInProgress(), TupleDescInitEntry(), UInt32GetDatum(), values, wal_segment_size, XLByteToSeg, XLogFileName(), and XLogSegmentOffset.

Variable Documentation

backup_state

BackupState* backup_state = NULL

static

Definition at line 43 of file xlogfuncs.c.

Referenced by perform_base_backup(), pg_backup_start(), pg_backup_stop(), and PrepareForIncrementalBackup().

backupcontext

MemoryContext backupcontext = NULL

static

Definition at line 47 of file xlogfuncs.c.

Referenced by pg_backup_start(), and pg_backup_stop().

tablespace_map

StringInfo tablespace_map = NULL

static

Definition at line 44 of file xlogfuncs.c.

Referenced by perform_base_backup(), pg_backup_start(), and pg_backup_stop().