/*
* pg_start_backup: set up for taking an on-line backup dump
*
* Essentially what this does is to create a backup label file in $PGDATA,
* where it will be archived as part of the backup dump. The label file
* contains the user-supplied label string (typically this would be used
* to tell where the backup dump will be stored) and the starting time and
* starting WAL location for the dump.
*/
Datum
pg_start_backup(PG_FUNCTION_ARGS)
{
text *backupid = PG_GETARG_TEXT_P(0);
bool fast = PG_GETARG_BOOL(1);
char *backupidstr;
XLogRecPtr startpoint;
DIR *dir;
backupidstr = text_to_cstring(backupid);
if (!superuser() && !has_rolreplication(GetUserId()))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser or replication role to run a backup")));
/* Make sure we can open the directory with tablespaces in it */
dir = AllocateDir("pg_tblspc");
if (!dir)
ereport(ERROR,
(errmsg("could not open directory \"%s\": %m", "pg_tblspc")));
startpoint = do_pg_start_backup(backupidstr, fast, NULL, NULL,
dir, NULL, NULL, false, true);
FreeDir(dir);
PG_RETURN_LSN(startpoint);
}
/*
* pg_create_restore_point: a named point for restore
*
* Permission checking for this function is managed through the normal
* GRANT system.
*/
Datum
pg_create_restore_point(PG_FUNCTION_ARGS)
{
text *restore_name = PG_GETARG_TEXT_P(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);
}
/*
* pg_start_backup: set up for taking an on-line backup dump
*
* Essentially what this does is to create a backup label file in $PGDATA,
* where it will be archived as part of the backup dump. The label file
* contains the user-supplied label string (typically this would be used
* to tell where the backup dump will be stored) and the starting time and
* starting WAL location for the dump.
*
* Permission checking for this function is managed through the normal
* GRANT system.
*/
Datum
pg_start_backup(PG_FUNCTION_ARGS)
{
text *backupid = PG_GETARG_TEXT_P(0);
bool fast = PG_GETARG_BOOL(1);
bool exclusive = PG_GETARG_BOOL(2);
char *backupidstr;
XLogRecPtr startpoint;
DIR *dir;
backupidstr = text_to_cstring(backupid);
if (exclusive_backup_running || nonexclusive_backup_running)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("a backup is already in progress in this session")));
/* Make sure we can open the directory with tablespaces in it */
dir = AllocateDir("pg_tblspc");
if (!dir)
ereport(ERROR,
(errmsg("could not open directory \"%s\": %m", "pg_tblspc")));
if (exclusive)
{
startpoint = do_pg_start_backup(backupidstr, fast, NULL, NULL,
dir, NULL, NULL, false, true);
exclusive_backup_running = true;
}
else
{
MemoryContext oldcontext;
/*
* Label file and tablespace map file need to be long-lived, since they
* are read in pg_stop_backup.
*/
oldcontext = MemoryContextSwitchTo(TopMemoryContext);
label_file = makeStringInfo();
tblspc_map_file = makeStringInfo();
MemoryContextSwitchTo(oldcontext);
startpoint = do_pg_start_backup(backupidstr, fast, NULL, label_file,
dir, NULL, tblspc_map_file, false, true);
nonexclusive_backup_running = true;
before_shmem_exit(nonexclusive_base_backup_cleanup, (Datum) 0);
}
FreeDir(dir);
PG_RETURN_LSN(startpoint);
}
/*
* Report the last WAL replay location (same format as pg_start_backup etc)
*
* This is useful for determining how much of WAL is visible to read-only
* connections during recovery.
*/
Datum
pg_last_xlog_replay_location(PG_FUNCTION_ARGS)
{
XLogRecPtr recptr;
recptr = GetXLogReplayRecPtr(NULL);
if (recptr == 0)
PG_RETURN_NULL();
PG_RETURN_LSN(recptr);
}
/*
* Report the last WAL receive location (same format as pg_start_backup etc)
*
* This is useful for determining how much of WAL is guaranteed to be received
* and synced to disk by walreceiver.
*/
Datum
pg_last_xlog_receive_location(PG_FUNCTION_ARGS)
{
XLogRecPtr recptr;
recptr = GetWalRcvWriteRecPtr(NULL, NULL);
if (recptr == 0)
PG_RETURN_NULL();
PG_RETURN_LSN(recptr);
}
/*
* SQL function for writing logical decoding message into WAL.
*/
Datum
pg_logical_emit_message_bytea(PG_FUNCTION_ARGS)
{
bool transactional = PG_GETARG_BOOL(0);
char *prefix = text_to_cstring(PG_GETARG_TEXT_PP(1));
bytea *data = PG_GETARG_BYTEA_PP(2);
XLogRecPtr lsn;
lsn = LogLogicalMessage(prefix, VARDATA_ANY(data), VARSIZE_ANY_EXHDR(data),
transactional);
PG_RETURN_LSN(lsn);
}
/*
* pg_stop_backup: finish taking an on-line backup dump
*
* We write an end-of-backup WAL record, and remove the backup label file
* created by pg_start_backup, creating a backup history file in pg_xlog
* instead (whence it will immediately be archived). The backup history file
* contains the same info found in the label file, plus the backup-end time
* and WAL location. Before 9.0, the backup-end time was read from the backup
* history file at the beginning of archive recovery, but we now use the WAL
* record for that and the file is for informational and debug purposes only.
*
* Note: different from CancelBackup which just cancels online backup mode.
*/
Datum
pg_stop_backup(PG_FUNCTION_ARGS)
{
XLogRecPtr stoppoint;
if (!superuser() && !has_rolreplication(GetUserId()))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser or replication role to run a backup"))));
stoppoint = do_pg_stop_backup(NULL, true, NULL);
PG_RETURN_LSN(stoppoint);
}
/*
* Report the current WAL flush location (same format as pg_start_backup etc)
*
* This function is mostly for debugging purposes.
*/
Datum
pg_current_xlog_flush_location(PG_FUNCTION_ARGS)
{
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();
PG_RETURN_LSN(current_recptr);
}
/*
* pg_switch_xlog: switch to next xlog file
*
* Permission checking for this function is managed through the normal
* GRANT system.
*/
Datum
pg_switch_xlog(PG_FUNCTION_ARGS)
{
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();
/*
* As a convenience, return the WAL location of the switch record
*/
PG_RETURN_LSN(switchpoint);
}
/*
* pg_start_backup: set up for taking an on-line backup dump
*
* Essentially what this does is to create a backup label file in $PGDATA,
* where it will be archived as part of the backup dump. The label file
* contains the user-supplied label string (typically this would be used
* to tell where the backup dump will be stored) and the starting time and
* starting WAL location for the dump.
*/
Datum
pg_start_backup(PG_FUNCTION_ARGS)
{
text *backupid = PG_GETARG_TEXT_P(0);
bool fast = PG_GETARG_BOOL(1);
char *backupidstr;
XLogRecPtr startpoint;
backupidstr = text_to_cstring(backupid);
if (!superuser() && !has_rolreplication(GetUserId()))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser or replication role to run a backup")));
startpoint = do_pg_start_backup(backupidstr, fast, NULL, NULL);
PG_RETURN_LSN(startpoint);
}
/*
* pg_stop_backup: finish taking an on-line backup dump
*
* We write an end-of-backup WAL record, and remove the backup label file
* created by pg_start_backup, creating a backup history file in pg_xlog
* instead (whence it will immediately be archived). The backup history file
* contains the same info found in the label file, plus the backup-end time
* and WAL location. Before 9.0, the backup-end time was read from the backup
* history file at the beginning of archive recovery, but we now use the WAL
* record for that and the file is for informational and debug purposes only.
*
* Note: different from CancelBackup which just cancels online backup mode.
*
* Note: this version is only called to stop an exclusive backup. The function
* pg_stop_backup_v2 (overloaded as pg_stop_backup in SQL) is called to
* stop non-exclusive backups.
*
* Permission checking for this function is managed through the normal
* GRANT system.
*/
Datum
pg_stop_backup(PG_FUNCTION_ARGS)
{
XLogRecPtr stoppoint;
if (nonexclusive_backup_running)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("non-exclusive backup in progress"),
errhint("did you mean to use pg_stop_backup('f')?")));
/*
* Exclusive backups were typically started in a different connection,
* so don't try to verify that exclusive_backup_running is set in this one.
* Actual verification that an exclusive backup is in fact running is handled
* inside do_pg_stop_backup.
*/
stoppoint = do_pg_stop_backup(NULL, true, NULL);
exclusive_backup_running = false;
PG_RETURN_LSN(stoppoint);
}
