From f77d141b7c5a5bbb81391126e80673b2d927a154 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Sun, 15 Dec 2013 23:41:42 +0900
Subject: [PATCH] Simplify beginning of database backup

It was unclear what was being errored out at the beginning of the
process. But it happens that it is just necessary to check if the
backup running is only an archive or not, then return a NULL file
list before continuing process. This should be part of some safety
checks though.
---
 backup.c  | 61 ++++++++++++++++++++++++++-----------------------------
 pg_rman.h |  2 +-
 2 files changed, 30 insertions(+), 33 deletions(-)

diff --git a/backup.c b/backup.c
index e53db749..0cccbb91 100644
--- a/backup.c
+++ b/backup.c
@@ -63,7 +63,7 @@ static void create_file_list(parray *files, const char *root, const char *prefix
 static TimeLineID get_current_timeline(void);
 
 /*
- * Take a backup of database.
+ * Take a backup of database and return the list of files backed up.
  */
 static parray *
 do_backup_database(parray *backup_list, pgBackupOption bkupopt)
@@ -75,36 +75,34 @@ do_backup_database(parray *backup_list, pgBackupOption bkupopt)
 	char		path[MAXPGPATH];
 	char		label[1024];
 	XLogRecPtr *lsn = NULL;
-	char		prev_file_txt[MAXPGPATH];	/* path of the previous backup list file */
-	bool		has_backup_label  = true;	/* flag if backup_label is there  */
+	char		prev_file_txt[MAXPGPATH];	/* path of the previous backup
+											 * list file */
+	bool		has_backup_label  = true;	/* flag if backup_label is there */
 
 	/* repack the options */
 	bool	smooth_checkpoint = bkupopt.smooth_checkpoint;
 
-	if (!HAVE_DATABASE(&current)) {
-		/* check if arclog backup. if arclog backup and no suitable full backup, */
-		/* take full backup instead. */
-		if (HAVE_ARCLOG(&current)) {
-			pgBackup   *prev_backup;
+	/*
+	 * In archive backup mode, check if there is an already validated
+	 * full backup on current timeline.
+	 */
+	if (current.backup_mode == BACKUP_MODE_ARCHIVE)
+	{
+		pgBackup   *prev_backup;
 
-			/* find last completed database backup */
-			prev_backup = catalog_get_last_data_backup(backup_list);
-			if (prev_backup == NULL)
-			{
-				elog(ERROR_SYSTEM, _("There is indeed a full backup but it is not validated."
-							"So I can't take any arclog backup."
-							"Please validate it and retry."));
-///				elog(INFO, _("no previous full backup, performing a full backup instead"));
-///				current.backup_mode = BACKUP_MODE_FULL;
-			}
+		prev_backup = catalog_get_last_data_backup(backup_list);
+		if (prev_backup == NULL)
+		{
+			elog(ERROR_SYSTEM, _("Full backup detected but it is not "
+					"validated so archive backup cannot be taken. "
+					"backup. Validate it and retry."));
 		}
-		else
-			return NULL;
+		return NULL;
 	}
 
 	elog(INFO, _("database backup start"));
 
-	/* initialize size summary */
+	/* Initialize size summary */
 	current.total_data_bytes = 0;
 	current.read_data_bytes = 0;
 
@@ -123,14 +121,14 @@ do_backup_database(parray *backup_list, pgBackupOption bkupopt)
 	/* If backup_label does not exist in $PGDATA, stop taking backup */
 	snprintf(path, lengthof(path), "%s/backup_label", pgdata);
 	make_native_path(path);
-	if (!fileExists(path)) {
+	if (!fileExists(path))
 		has_backup_label = false;
-	}
+
 	snprintf(path, lengthof(path), "%s/recovery.conf", pgdata);
 	make_native_path(path);
-	if (fileExists(path)) {
+	if (fileExists(path))
 		current.is_from_standby = true;
-	}
+
 	if (!has_backup_label && !current.is_from_standby)
 	{
 		if (verbose)
@@ -140,10 +138,8 @@ do_backup_database(parray *backup_list, pgBackupOption bkupopt)
 	}
 
 	/*
-	 * list directories and symbolic links  with the physical path to make
-	 * mkdirs.sh
-	 * Sort in order of path.
-	 * omit $PGDATA.
+	 * List directories and symbolic links with the physical path to make
+	 * mkdirs.sh, then sort them in order of path. Omit $PGDATA.
 	 */
 	files = parray_new();
 	dir_list_file(files, pgdata, NULL, false, false);
@@ -433,7 +429,7 @@ do_backup_database(parray *backup_list, pgBackupOption bkupopt)
 
 
 /*
- * backup archived WAL incrementally.
+ * Backup archived WAL incrementally.
  */
 static parray *
 do_backup_arclog(parray *backup_list)
@@ -449,8 +445,9 @@ do_backup_arclog(parray *backup_list)
 	int64		arclog_write_bytes = 0;
 	char		last_wal[MAXPGPATH];
 
-	if (!HAVE_ARCLOG(&current))
-		return NULL;
+	Assert(current.backup_mode == BACKUP_MODE_ARCHIVE ||
+		   current.backup_mode == BACKUP_MODE_INCREMENTAL ||
+		   current.backup_mode == BACKUP_MODE_FULL);
 
 	if (verbose)
 	{
diff --git a/pg_rman.h b/pg_rman.h
index ee43b8c4..3987df36 100644
--- a/pg_rman.h
+++ b/pg_rman.h
@@ -144,7 +144,7 @@ typedef struct pgBackup
 	time_t		recovery_time;
 	uint32		recovery_xid;
 
-	/* Size (-1 means not-backup'ed) */
+	/* Size (-1 means nothing was backed up) */
 	int64		total_data_bytes;
 	int64		read_data_bytes;
 	int64		read_arclog_bytes;