Merge lp:~akopytov/percona-xtrabackup/bug1217426-2.2 into lp:percona-xtrabackup/2.2

[Alexey Kopytov]

Bug #1217426: Empty directory is not backed when stream is used

The problem was that innobackupex ignored empty directories when
creating streaming backups. Normally a database created by the server
contains a ?db.opt? file, and so the corresponding directory is not
empty. However, in some circumstances a database may be created with
?mkdir?. This is what mysql_install_db does to create the default ?test?
database. Since there are no files to send into the
stream, the resulting stream would contain no references to the empty
directory, so it would not be created when the stream is unpacked and
thus, missing in the backup. Which resulted in inconsistency between the
original data directory and the one after restoring from the backup.

One solution to this problem would be to stream empty directories. This
is rather complicated from the implementation point of view. Since both
xbcrypt and xbstream only deal with files, it would require implementing
support for directory units, i.e. introducing new ?directory? chunk
types, bumping the format version, modifications to the datasink API and
utility command line interface, etc.

A much easier solution is to stream a fake empty ?db.opt? file for empty
directories. This way the corresponding database will be present in the
backup, and the empty db.opt file will be ignored by the server after
restore.

http://jenkins.percona.com/view/XtraBackup/job/percona-xtrabackup-2.2-param/15/

[Sergei Glushchenko (sergei.glushchenko)]

Approve

review: Approve (g2)

[Alexey Kopytov (akopytov)]

review: Approve

=== modified file 'xtrabackup/innobackupex'
--- xtrabackup/innobackupex	2013-09-26 06:26:18 +0000
+++ xtrabackup/innobackupex	2013-09-26 11:19:41 +0000
@@ -4018,6 +4018,25 @@
             print STDERR "$prefix Backing up files " . 
                 "'$source_dir/$database/$wildcard' ($file_c files)\n";
         }
+
+        if ($file_c == 0 && $option_stream) {
+            # Stream/encrypt empty directories by backing up a fake empty
+            # db.opt file, so that empty databases are created in the backup
+            mkdir("$option_tmpdir/$database") ||
+                die "Failed to create directory $option_tmpdir/$database: $!";
+
+            open XTRABACKUP_FH, "> $option_tmpdir/$database/db.opt"
+                || die "Cannot create file $option_tmpdir/db.opt: $!";
+            close XTRABACKUP_FH;
+
+            backup_file_via_stream("$option_tmpdir", "$database/db.opt");
+
+            unlink("$option_tmpdir/$database/db.opt") ||
+                die "Failed to remove file $database/db.opt: $!";
+            rmdir("$option_tmpdir/$database") ||
+                die "Failed to remove directory $database: $!";
+        }
+
         foreach $file (@list) {
             next unless check_if_required($database, $file);
 

=== modified file 'xtrabackup/test/inc/ib_stream_common.sh'
--- xtrabackup/test/inc/ib_stream_common.sh	2013-06-05 19:15:00 +0000
+++ xtrabackup/test/inc/ib_stream_common.sh	2013-09-26 11:19:41 +0000
@@ -55,3 +55,11 @@
 start_server
 # Check sakila
 run_cmd ${MYSQL} ${MYSQL_ARGS} -e "SELECT count(*) from actor" sakila
+
+########################################################################
+# Bug #1217426: Empty directory is not backed when stream is used
+########################################################################
+
+# Check if the 'test' database is accessible by the server
+run_cmd ${MYSQL} ${MYSQL_ARGS} -e "CREATE TABLE t(a INT)" test
+run_cmd ${MYSQL} ${MYSQL_ARGS} -e "SELECT * FROM t" test

=== modified file 'xtrabackup/test/inc/xb_local.sh'
--- xtrabackup/test/inc/xb_local.sh	2013-07-25 22:02:50 +0000
+++ xtrabackup/test/inc/xb_local.sh	2013-09-26 11:19:41 +0000
@@ -52,3 +52,9 @@
 start_server
 # Check sakila
 run_cmd ${MYSQL} ${MYSQL_ARGS} -e "SELECT count(*) from actor" sakila
+
+########################################################################
+# Bug #1217426: Empty directory is not backed when stream is used
+########################################################################
+run_cmd ${MYSQL} ${MYSQL_ARGS} -e "CREATE TABLE t(a INT)" test
+run_cmd ${MYSQL} ${MYSQL_ARGS} -e "SELECT * FROM t" test

=== modified file 'xtrabackup/test/t/ib_rsync.sh'
--- xtrabackup/test/t/ib_rsync.sh	2013-08-14 18:36:12 +0000
+++ xtrabackup/test/t/ib_rsync.sh	2013-09-26 11:19:41 +0000
@@ -34,3 +34,9 @@
 
 start_server
 run_cmd ${MYSQL} ${MYSQL_ARGS} -e "SELECT COUNT(*) FROM actor" sakila
+
+########################################################################
+# Bug #1217426: Empty directory is not backed when stream is used
+########################################################################
+run_cmd ${MYSQL} ${MYSQL_ARGS} -e "CREATE TABLE t(a INT)" test
+run_cmd ${MYSQL} ${MYSQL_ARGS} -e "SELECT * FROM t" test