/*------------------------------------------------------------------------- * * pgespresso.c * * * Copyright (c) 2014, 2ndQuadrant Limited * * Authors: Simon Riggs * Marco Nenciarini * Gabriele Bartolini * * 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(); }