*** a/src/backend/access/transam/xlog.c --- b/src/backend/access/transam/xlog.c *************** *** 60,67 **** /* File path names (all relative to $PGDATA) */ - #define BACKUP_LABEL_FILE "backup_label" - #define BACKUP_LABEL_OLD "backup_label.old" #define RECOVERY_COMMAND_FILE "recovery.conf" #define RECOVERY_COMMAND_DONE "recovery.done" --- 60,65 ---- *************** *** 339,344 **** typedef struct XLogCtlInsert --- 337,351 ---- char *currpos; /* current insertion point in cache */ XLogRecPtr RedoRecPtr; /* current redo point for insertions */ bool forcePageWrites; /* forcing full-page writes for PITR? */ + + /* + * exclusiveBackup is true if a backup started with pg_start_backup() is + * in progress, and nonExclusiveBackups is a counter indicating the number + * of streaming base backups currently in progress. forcePageWrites is + * set to true, when either of these is non-zero. + */ + bool exclusiveBackup; + int nonExclusiveBackups; } XLogCtlInsert; /* *************** *** 8352,8367 **** pg_start_backup(PG_FUNCTION_ARGS) backupidstr = text_to_cstring(backupid); ! startpoint = do_pg_start_backup(backupidstr, fast); snprintf(startxlogstr, sizeof(startxlogstr), "%X/%X", startpoint.xlogid, startpoint.xrecoff); PG_RETURN_TEXT_P(cstring_to_text(startxlogstr)); } XLogRecPtr ! do_pg_start_backup(const char *backupidstr, bool fast) { XLogRecPtr checkpointloc; XLogRecPtr startpoint; pg_time_t stamp_time; --- 8359,8396 ---- backupidstr = text_to_cstring(backupid); ! startpoint = do_pg_start_backup(backupidstr, fast, NULL); snprintf(startxlogstr, sizeof(startxlogstr), "%X/%X", startpoint.xlogid, startpoint.xrecoff); PG_RETURN_TEXT_P(cstring_to_text(startxlogstr)); } + /* + * do_pg_start_backup is the workhorse of the user-visible pg_start_backup() + * function. It creates the necessary starting checkpoint and constructs the + * backup label file. + * + * There are two kind of backups: exclusive and non-exclusive. An exclusive + * backup is started with pg_start_backup(), and there can be only one active + * at a time. The backup label file of an exclusive backup is written to + * $PGDATA/backup_label, and it is removed by pg_stop_backup(). + * + * A non-exclusive backup is used for the streaming base backups (see + * src/backend/replication/basebackup.c). The difference to exclusive backups + * is that the backup label file is not written to disk. Instead, its would-be + * contents are returned in *labelfile, and the caller is responsible for + * including it in the backup archive as 'backup_label'. There can be many + * non-exclusive backups active at the same time, and they don't conflict + * with an exclusive backup either. + * + * Every successfully started non-exclusive backup must be stopped by calling + * do_pg_stop_backup() or do_pg_abort_backup(). + */ XLogRecPtr ! do_pg_start_backup(const char *backupidstr, bool fast, char **labelfile) { + bool exclusive = (labelfile == NULL); XLogRecPtr checkpointloc; XLogRecPtr startpoint; pg_time_t stamp_time; *************** *** 8371,8381 **** do_pg_start_backup(const char *backupidstr, bool fast) uint32 _logSeg; struct stat stat_buf; FILE *fp; ! if (!superuser() && !is_authenticated_user_replication_role()) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), ! errmsg("must be superuser or replication role to run a backup"))); if (RecoveryInProgress()) ereport(ERROR, --- 8400,8411 ---- uint32 _logSeg; struct stat stat_buf; FILE *fp; + StringInfoData labelfbuf; ! if (exclusive && !superuser()) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), ! errmsg("must be superuser to run a backup"))); if (RecoveryInProgress()) ereport(ERROR, *************** *** 8389,8394 **** do_pg_start_backup(const char *backupidstr, bool fast) --- 8419,8430 ---- errmsg("WAL level not sufficient for making an online backup"), errhint("wal_level must be set to \"archive\" or \"hot_standby\" at server start."))); + if (strlen(backupidstr) > MAXPGPATH) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("backup label too long (max %d bytes)", + MAXPGPATH))); + /* * Mark backup active in shared memory. We must do full-page WAL writes * during an on-line backup even if not doing so at other times, because *************** *** 8407,8420 **** do_pg_start_backup(const char *backupidstr, bool fast) * ensure adequate interlocking against XLogInsert(). */ LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); ! if (XLogCtl->Insert.forcePageWrites) { ! LWLockRelease(WALInsertLock); ! ereport(ERROR, ! (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), ! errmsg("a backup is already in progress"), ! errhint("Run pg_stop_backup() and try again."))); } XLogCtl->Insert.forcePageWrites = true; LWLockRelease(WALInsertLock); --- 8443,8462 ---- * ensure adequate interlocking against XLogInsert(). */ LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); ! if (exclusive) { ! if (XLogCtl->Insert.exclusiveBackup) ! { ! LWLockRelease(WALInsertLock); ! ereport(ERROR, ! (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), ! errmsg("a backup is already in progress"), ! errhint("Run pg_stop_backup() and try again."))); ! } ! XLogCtl->Insert.exclusiveBackup = true; } + else + XLogCtl->Insert.nonExclusiveBackups++; XLogCtl->Insert.forcePageWrites = true; LWLockRelease(WALInsertLock); *************** *** 8432,8438 **** do_pg_start_backup(const char *backupidstr, bool fast) RequestXLogSwitch(); /* Ensure we release forcePageWrites if fail below */ ! PG_ENSURE_ERROR_CLEANUP(pg_start_backup_callback, (Datum) 0); { /* * Force a CHECKPOINT. Aside from being necessary to prevent torn --- 8474,8480 ---- RequestXLogSwitch(); /* Ensure we release forcePageWrites if fail below */ ! PG_ENSURE_ERROR_CLEANUP(pg_start_backup_callback, (Datum) BoolGetDatum(exclusive)); { /* * Force a CHECKPOINT. Aside from being necessary to prevent torn *************** *** 8459,8512 **** do_pg_start_backup(const char *backupidstr, bool fast) XLByteToSeg(startpoint, _logId, _logSeg); XLogFileName(xlogfilename, ThisTimeLineID, _logId, _logSeg); /* Use the log timezone here, not the session timezone */ stamp_time = (pg_time_t) time(NULL); pg_strftime(strfbuf, sizeof(strfbuf), "%Y-%m-%d %H:%M:%S %Z", pg_localtime(&stamp_time, log_timezone)); /* ! * Check for existing backup label --- implies a backup is already ! * running. (XXX given that we checked forcePageWrites above, maybe ! * it would be OK to just unlink any such label file?) */ ! if (stat(BACKUP_LABEL_FILE, &stat_buf) != 0) { ! if (errno != ENOENT) ereport(ERROR, (errcode_for_file_access(), ! errmsg("could not stat file \"%s\": %m", BACKUP_LABEL_FILE))); } else ! ereport(ERROR, ! (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), ! errmsg("a backup is already in progress"), ! errhint("If you're sure there is no backup in progress, remove file \"%s\" and try again.", ! BACKUP_LABEL_FILE))); ! ! /* ! * Okay, write the file ! */ ! fp = AllocateFile(BACKUP_LABEL_FILE, "w"); ! if (!fp) ! ereport(ERROR, ! (errcode_for_file_access(), ! errmsg("could not create file \"%s\": %m", ! BACKUP_LABEL_FILE))); ! fprintf(fp, "START WAL LOCATION: %X/%X (file %s)\n", ! startpoint.xlogid, startpoint.xrecoff, xlogfilename); ! fprintf(fp, "CHECKPOINT LOCATION: %X/%X\n", ! checkpointloc.xlogid, checkpointloc.xrecoff); ! fprintf(fp, "START TIME: %s\n", strfbuf); ! fprintf(fp, "LABEL: %s\n", backupidstr); ! if (fflush(fp) || ferror(fp) || FreeFile(fp)) ! ereport(ERROR, ! (errcode_for_file_access(), ! errmsg("could not write file \"%s\": %m", ! BACKUP_LABEL_FILE))); } ! PG_END_ENSURE_ERROR_CLEANUP(pg_start_backup_callback, (Datum) 0); /* * We're done. As a convenience, return the starting WAL location. --- 8501,8567 ---- XLByteToSeg(startpoint, _logId, _logSeg); XLogFileName(xlogfilename, ThisTimeLineID, _logId, _logSeg); + /* + * Construct backup label file + */ + initStringInfo(&labelfbuf); + /* Use the log timezone here, not the session timezone */ stamp_time = (pg_time_t) time(NULL); pg_strftime(strfbuf, sizeof(strfbuf), "%Y-%m-%d %H:%M:%S %Z", pg_localtime(&stamp_time, log_timezone)); + appendStringInfo(&labelfbuf, "START WAL LOCATION: %X/%X (file %s)\n", + startpoint.xlogid, startpoint.xrecoff, xlogfilename); + appendStringInfo(&labelfbuf, "CHECKPOINT LOCATION: %X/%X\n", + checkpointloc.xlogid, checkpointloc.xrecoff); + appendStringInfo(&labelfbuf, "START TIME: %s\n", strfbuf); + appendStringInfo(&labelfbuf, "LABEL: %s\n", backupidstr); /* ! * Okay, write the file, or return its contents to caller. */ ! if (exclusive) { ! /* ! * Check for existing backup label --- implies a backup is already ! * running. (XXX given that we checked exclusiveBackup above, maybe ! * it would be OK to just unlink any such label file?) ! */ ! if (stat(BACKUP_LABEL_FILE, &stat_buf) != 0) ! { ! if (errno != ENOENT) ! ereport(ERROR, ! (errcode_for_file_access(), ! errmsg("could not stat file \"%s\": %m", ! BACKUP_LABEL_FILE))); ! } ! else ! ereport(ERROR, ! (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), ! errmsg("a backup is already in progress"), ! errhint("If you're sure there is no backup in progress, remove file \"%s\" and try again.", ! BACKUP_LABEL_FILE))); ! ! fp = AllocateFile(BACKUP_LABEL_FILE, "w"); ! ! if (!fp) ereport(ERROR, (errcode_for_file_access(), ! errmsg("could not create file \"%s\": %m", BACKUP_LABEL_FILE))); + fwrite(labelfbuf.data, labelfbuf.len, 1, fp); + if (fflush(fp) || ferror(fp) || FreeFile(fp)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write file \"%s\": %m", + BACKUP_LABEL_FILE))); + pfree(labelfbuf.data); } else ! *labelfile = labelfbuf.data; } ! PG_END_ENSURE_ERROR_CLEANUP(pg_start_backup_callback, (Datum) BoolGetDatum(exclusive)); /* * We're done. As a convenience, return the starting WAL location. *************** *** 8518,8526 **** do_pg_start_backup(const char *backupidstr, bool fast) static void pg_start_backup_callback(int code, Datum arg) { ! /* Turn off forcePageWrites on failure */ LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); ! XLogCtl->Insert.forcePageWrites = false; LWLockRelease(WALInsertLock); } --- 8573,8592 ---- static void pg_start_backup_callback(int code, Datum arg) { ! bool exclusive = DatumGetBool(arg); ! ! /* Update backup counters and forcePageWrites on failure */ LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); ! if (exclusive) ! { ! Assert(XLogCtl->Insert.exclusiveBackup); ! XLogCtl->Insert.exclusiveBackup = false; ! } ! else ! XLogCtl->Insert.nonExclusiveBackups--; ! ! if (!XLogCtl->Insert.exclusiveBackup && XLogCtl->Insert.nonExclusiveBackups == 0) ! XLogCtl->Insert.forcePageWrites = false; LWLockRelease(WALInsertLock); } *************** *** 8543,8558 **** pg_stop_backup(PG_FUNCTION_ARGS) XLogRecPtr stoppoint; char stopxlogstr[MAXFNAMELEN]; ! stoppoint = do_pg_stop_backup(); snprintf(stopxlogstr, sizeof(stopxlogstr), "%X/%X", stoppoint.xlogid, stoppoint.xrecoff); PG_RETURN_TEXT_P(cstring_to_text(stopxlogstr)); } XLogRecPtr ! do_pg_stop_backup(void) { XLogRecPtr startpoint; XLogRecPtr stoppoint; XLogRecData rdata; --- 8609,8632 ---- XLogRecPtr stoppoint; char stopxlogstr[MAXFNAMELEN]; ! stoppoint = do_pg_stop_backup(NULL); snprintf(stopxlogstr, sizeof(stopxlogstr), "%X/%X", stoppoint.xlogid, stoppoint.xrecoff); PG_RETURN_TEXT_P(cstring_to_text(stopxlogstr)); } + /* + * do_pg_start_backup is the workhorse of the user-visible pg_stop_backup() + * function. + + * If labelfile is NULL, this stops an exclusive backup. Otherwise this stops + * the non-exclusive backup specified by 'labelfile'. + */ XLogRecPtr ! do_pg_stop_backup(char *labelfile) { + bool exclusive = (labelfile == NULL); XLogRecPtr startpoint; XLogRecPtr stoppoint; XLogRecData rdata; *************** *** 8568,8582 **** do_pg_stop_backup(void) FILE *lfp; FILE *fp; char ch; - int ich; int seconds_before_warning; int waits = 0; bool reported_waiting = false; ! if (!superuser() && !is_authenticated_user_replication_role()) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), ! (errmsg("must be superuser or replication role to run a backup")))); if (RecoveryInProgress()) ereport(ERROR, --- 8642,8656 ---- FILE *lfp; FILE *fp; char ch; int seconds_before_warning; int waits = 0; bool reported_waiting = false; + char *remaining; ! if (exclusive && !superuser()) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), ! errmsg("must be superuser to run a backup"))); if (RecoveryInProgress()) ereport(ERROR, *************** *** 8591,8628 **** do_pg_stop_backup(void) errhint("wal_level must be set to \"archive\" or \"hot_standby\" at server start."))); /* ! * OK to clear forcePageWrites */ LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); ! XLogCtl->Insert.forcePageWrites = false; LWLockRelease(WALInsertLock); ! /* ! * Open the existing label file ! */ ! lfp = AllocateFile(BACKUP_LABEL_FILE, "r"); ! if (!lfp) { ! if (errno != ENOENT) ereport(ERROR, (errcode_for_file_access(), errmsg("could not read file \"%s\": %m", BACKUP_LABEL_FILE))); ! ereport(ERROR, ! (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), ! errmsg("a backup is not in progress"))); } /* * Read and parse the START WAL LOCATION line (this code is pretty crude, * but we are not expecting any variability in the file format). */ ! if (fscanf(lfp, "START WAL LOCATION: %X/%X (file %24s)%c", &startpoint.xlogid, &startpoint.xrecoff, startxlogfilename, &ch) != 4 || ch != '\n') ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE))); /* * Write the backup-end xlog record --- 8665,8749 ---- errhint("wal_level must be set to \"archive\" or \"hot_standby\" at server start."))); /* ! * OK to update backup counters and forcePageWrites */ LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); ! if (exclusive) ! XLogCtl->Insert.exclusiveBackup = false; ! else ! { ! /* ! * The user-visible pg_start/stop_backup() functions that operate on ! * exclusive backups can be called at any time, but for non-exclusive ! * backups, it is expected that each do_pg_start_backup() call is ! * matched by exactly one do_pg_stop_backup() call. ! */ ! Assert(XLogCtl->Insert.nonExclusiveBackups > 0); ! XLogCtl->Insert.nonExclusiveBackups--; ! } ! ! if (!XLogCtl->Insert.exclusiveBackup && XLogCtl->Insert.nonExclusiveBackups == 0) ! XLogCtl->Insert.forcePageWrites = false; LWLockRelease(WALInsertLock); ! if (exclusive) { ! /* ! * Read the existing label file into memory. ! */ ! struct stat statbuf; ! int r; ! ! if (stat(BACKUP_LABEL_FILE, &statbuf)) ! { ! if (errno != ENOENT) ! ereport(ERROR, ! (errcode_for_file_access(), ! errmsg("could not stat file \"%s\": %m", ! BACKUP_LABEL_FILE))); ! ereport(ERROR, ! (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), ! errmsg("a backup is not in progress"))); ! } ! ! lfp = AllocateFile(BACKUP_LABEL_FILE, "r"); ! if (!lfp) ! { ereport(ERROR, (errcode_for_file_access(), errmsg("could not read file \"%s\": %m", BACKUP_LABEL_FILE))); ! } ! labelfile = palloc(statbuf.st_size + 1); ! r = fread(labelfile, statbuf.st_size, 1, lfp); ! labelfile[statbuf.st_size] = '\0'; ! ! /* ! * Close and remove the backup label file ! */ ! if (r != 1 || ferror(lfp) || FreeFile(lfp)) ! ereport(ERROR, ! (errcode_for_file_access(), ! errmsg("could not read file \"%s\": %m", ! BACKUP_LABEL_FILE))); ! if (unlink(BACKUP_LABEL_FILE) != 0) ! ereport(ERROR, ! (errcode_for_file_access(), ! errmsg("could not remove file \"%s\": %m", ! BACKUP_LABEL_FILE))); } /* * Read and parse the START WAL LOCATION line (this code is pretty crude, * but we are not expecting any variability in the file format). */ ! if (sscanf(labelfile, "START WAL LOCATION: %X/%X (file %24s)%c", &startpoint.xlogid, &startpoint.xrecoff, startxlogfilename, &ch) != 4 || ch != '\n') ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE))); + remaining = strchr(labelfile, '\n') + 1; /* %n is not portable enough */ /* * Write the backup-end xlog record *************** *** 8665,8672 **** do_pg_stop_backup(void) fprintf(fp, "STOP WAL LOCATION: %X/%X (file %s)\n", stoppoint.xlogid, stoppoint.xrecoff, stopxlogfilename); /* transfer remaining lines from label to history file */ ! while ((ich = fgetc(lfp)) != EOF) ! fputc(ich, fp); fprintf(fp, "STOP TIME: %s\n", strfbuf); if (fflush(fp) || ferror(fp) || FreeFile(fp)) ereport(ERROR, --- 8786,8792 ---- fprintf(fp, "STOP WAL LOCATION: %X/%X (file %s)\n", stoppoint.xlogid, stoppoint.xrecoff, stopxlogfilename); /* transfer remaining lines from label to history file */ ! fprintf(fp, "%s", remaining); fprintf(fp, "STOP TIME: %s\n", strfbuf); if (fflush(fp) || ferror(fp) || FreeFile(fp)) ereport(ERROR, *************** *** 8675,8694 **** do_pg_stop_backup(void) histfilepath))); /* - * Close and remove the backup label file - */ - if (ferror(lfp) || FreeFile(lfp)) - ereport(ERROR, - (errcode_for_file_access(), - errmsg("could not read file \"%s\": %m", - BACKUP_LABEL_FILE))); - if (unlink(BACKUP_LABEL_FILE) != 0) - ereport(ERROR, - (errcode_for_file_access(), - errmsg("could not remove file \"%s\": %m", - BACKUP_LABEL_FILE))); - - /* * Clean out any no-longer-needed history files. As a side effect, this * will post a .ready file for the newly created history file, notifying * the archiver that history file may be archived immediately. --- 8795,8800 ---- *************** *** 8769,8796 **** do_pg_stop_backup(void) /* * do_pg_abort_backup: abort a running backup * ! * This does just the most basic steps of pg_stop_backup(), by taking the * system out of backup mode, thus making it a lot more safe to call from * an error handler. */ void do_pg_abort_backup(void) { - /* - * OK to clear forcePageWrites - */ LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); ! XLogCtl->Insert.forcePageWrites = false; ! LWLockRelease(WALInsertLock); ! /* ! * Remove backup label file ! */ ! if (unlink(BACKUP_LABEL_FILE) != 0) ! ereport(ERROR, ! (errcode_for_file_access(), ! errmsg("could not remove file \"%s\": %m", ! BACKUP_LABEL_FILE))); } /* --- 8875,8899 ---- /* * do_pg_abort_backup: abort a running backup * ! * This does just the most basic steps of do_pg_stop_backup(), by taking the * system out of backup mode, thus making it a lot more safe to call from * an error handler. + * + * NB: This is only for aborting a non-exclusive backup that doesn't write + * backup_label. A backup started with pg_stop_backup() needs to be finished + * with pg_stop_backup(). */ void do_pg_abort_backup(void) { LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); ! Assert(XLogCtl->Insert.nonExclusiveBackups > 0); ! XLogCtl->Insert.nonExclusiveBackups--; ! if (!XLogCtl->Insert.exclusiveBackup && XLogCtl->Insert.nonExclusiveBackups == 0) ! XLogCtl->Insert.forcePageWrites = false; ! ! LWLockRelease(WALInsertLock); } /*