Merge lp:~gaul/percona-server/purge-changed-page-bitmaps into lp:percona-server/5.6

[Andrew Gaul]

[Laurynas Biveinis (laurynas-biveinis)]

The fix is being included in a modified form.

review: Needs Resubmitting

[Andrew Gaul (gaul)]

Superseded by https://code.launchpad.net/~laurynas-biveinis/percona-server/bug1260035-5.6 .

Unmerged revisions

509. By Andrew Gaul <email address hidden> on 2013-12-11

Consider end LSN when purging changed page bitmaps

Fixes: https://bugs.launchpad.net/percona-server/+bug/1260035

=== modified file 'Percona-Server/storage/innobase/log/log0online.cc'
--- Percona-Server/storage/innobase/log/log0online.cc	2013-09-25 06:04:21 +0000
+++ Percona-Server/storage/innobase/log/log0online.cc	2013-12-11 18:57:57 +0000
@@ -1797,8 +1797,17 @@
 	}
 
 	for (i = 0; i < bitmap_files.count; i++) {
-		if (bitmap_files.files[i].seq_num == 0
-		    || bitmap_files.files[i].start_lsn >= lsn) {
+		/* We consider the end LSN of the current bitmap, derived from
+		the start LSN of the subsequent bitmap file, to determine
+		whether to remove the current bitmap.  Note that bitmap_files
+		does not contain an entry for the bitmap past the given LSN so
+		we must check the boundary conditions as well.  For example,
+		consider 1_0.xdb and 2_10.xdb and querying LSN 5.  bitmap_files
+		will only contain 1_0.xdb and we must not delete it since it
+		represents LSNs 0-9. */
+		if (i + 1 == bitmap_files.count
+		    || bitmap_files.files[i + 1].seq_num == 0
+		    || bitmap_files.files[i + 1].start_lsn >= lsn) {
 
 			break;
 		}