forked from 2ndquadrant-it/pgespresso
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pgespresso.c
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/
pgespresso.c
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/*-------------------------------------------------------------------------
*
* pgespresso.c
*
*
* Copyright (c) 2014, 2ndQuadrant Limited <www.2ndquadrant.com>
*
* Authors: Simon Riggs <simon@2ndQuadrant.com>
* Marco Nenciarini <marco.nenciarini@2ndQuadrant.it>
* Gabriele Bartolini <gabriele.bartolini@2ndQuadrant.it>
*
* See COPYING for licensing information
*
* IDENTIFICATION
* pgespresso/pgespresso.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/xlog.h"
#include "access/xlog_internal.h"
#include "access/xlogdefs.h"
#include "utils/builtins.h"
#include "miscadmin.h"
PG_MODULE_MAGIC;
Datum pgespresso_start_backup(PG_FUNCTION_ARGS);
Datum pgespresso_stop_backup(PG_FUNCTION_ARGS);
Datum pgespresso_abort_backup(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(pgespresso_start_backup);
PG_FUNCTION_INFO_V1(pgespresso_stop_backup);
PG_FUNCTION_INFO_V1(pgespresso_abort_backup);
/*
* pgespresso_start_backup: set up for taking an on-line backup dump
*
* Essentially what this does is to return a backup label file that the
* user is responsible for placing in the $PGDATA of the backup AFTER
* the backup has been taken. The label file must not be written to the
* data directory of the server from which the backup is taken because
* this type of backup presumes and allows that more than one backup
* may be in progress at any one time. 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
pgespresso_start_backup(PG_FUNCTION_ARGS)
{
text *backupid = PG_GETARG_TEXT_P(0);
bool fast = PG_GETARG_BOOL(1);
char *backupidstr;
char *labelfile;
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")));
/*
* ThisTimeLineID is always 0 in a normal backend during recovery.
* We get latest redo apply position timeline and we update it globally
* to make do_pg_start_backup use the correct value when generating
* the backup label text
*/
if (RecoveryInProgress()) {
TimeLineID replayTLI;
GetXLogReplayRecPtr(&replayTLI);
ThisTimeLineID = replayTLI;
elog(DEBUG1, "updated ThisTimeLineID = %u", ThisTimeLineID);
}
/*
* Starting from 9.3 the do_pg_start_backup returns the timeline ID
* in *starttli_p additional argument
*/
#if PG_VERSION_NUM >= 90300
do_pg_start_backup(backupidstr, fast, NULL, &labelfile);
#else
do_pg_start_backup(backupidstr, fast, &labelfile);
#endif
PG_RETURN_TEXT_P(cstring_to_text(labelfile));
}
/*
* pgespresso_stop_backup: finish taking an on-line backup dump
*
* Only parameter is the labelfile returned from pg_start_concurrent_backup
*
* Return is the XLOG filename containing end of backup location, combining
* both the TLI and the end location. NOTE: the user is responsible for
* ensuring that the last file is correctly archived.
*/
Datum
pgespresso_stop_backup(PG_FUNCTION_ARGS)
{
XLogRecPtr stoppoint;
text *labelfile = PG_GETARG_TEXT_P(0);
char *backupidstr;
char xlogfilename[MAXFNAMELEN];
backupidstr = text_to_cstring(labelfile);
if (!superuser() && !has_rolreplication(GetUserId()))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser or replication role to run a backup"))));
#if PG_VERSION_NUM >= 90300
{
XLogSegNo xlogsegno;
TimeLineID endtli;
stoppoint = do_pg_stop_backup(backupidstr,
false, /* don't wait for archive */
&endtli);
XLByteToPrevSeg(stoppoint, xlogsegno);
XLogFileName(xlogfilename, endtli, xlogsegno);
}
#else
{
uint32 xlogid;
uint32 xlogseg;
stoppoint = do_pg_stop_backup(backupidstr,
false); /* don't wait for archive */
/*
* In 9.2 the do_pg_stop_backup doesn't return the timeline ID and
* ThisTimeLineID is always 0 in a normal backend during recovery.
* We get latest redo apply position timeline and we update it globally
*/
if (RecoveryInProgress()) {
TimeLineID replayTLI;
GetXLogReplayRecPtr(&replayTLI);
ThisTimeLineID = replayTLI;
elog(DEBUG1, "updated ThisTimeLineID = %u", ThisTimeLineID);
}
XLByteToPrevSeg(stoppoint, xlogid, xlogseg);
XLogFileName(xlogfilename, ThisTimeLineID, xlogid, xlogseg);
}
#endif
PG_RETURN_TEXT_P(cstring_to_text(xlogfilename));
}
/*
* pgespresso_abort_backup: abort a running backup
*
* This does just the most basic steps of pgespresso_stop_backup(), by taking
* the system out of backup mode, thus making it a lot more safe to call from
* an error handler.
*/
Datum
pgespresso_abort_backup(PG_FUNCTION_ARGS)
{
if (!superuser() && !has_rolreplication(GetUserId()))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser or replication role to run a backup"))));
do_pg_abort_backup();
PG_RETURN_VOID();
}