Merge lp:~akopytov/percona-server/bug1070856-5.5 into lp:percona-server/5.5

[Alexey Kopytov]

    Bug #1070856: Temporary files created by binary log cache are not purged
                  after transaction commit

    The problem was that the temporary file used to cache transactions for
    the binary log was initialized once (when the in-memory buffer was
    exceeded) and close (and thus, removed) only when closing the
    connection. Which might lead to problems with large temporary files
    being created and not removed in case of persistent connections and
    large transactions (i.e. LOAD DATA INFILE).

    Fixed by truncating the temporary file, if used for a binary log
    transaction cache, when committing or rolling back a statement or a
    transaction.

[Alexey Kopytov (akopytov)]

http://jenkins.percona.com/view/PS%205.5/job/percona-server-5.5-param/561/

[Alexey Kopytov (akopytov)]

ST 26926

[Vlad Lesin (vlad-lesin)]

Looks good. See my comment for 5.1.

[Vlad Lesin (vlad-lesin)]

I agree the code for testing such small fix would be redundant.

review: Approve

[George Ormond Lorch III (gl-az)]

review: Approve (g2)

[Laurynas Biveinis (laurynas-biveinis)]

review: Approve

=== modified file 'Percona-Server/include/my_sys.h'
--- Percona-Server/include/my_sys.h	2012-05-10 07:49:14 +0000
+++ Percona-Server/include/my_sys.h	2012-10-26 05:11:24 +0000
@@ -752,6 +752,7 @@
 				 const char *prefix, size_t cache_size,
 				 myf cache_myflags);
 extern my_bool real_open_cached_file(IO_CACHE *cache);
+extern my_bool truncate_cached_file(IO_CACHE *cache, my_off_t pos);
 extern void close_cached_file(IO_CACHE *cache);
 File create_temp_file(char *to, const char *dir, const char *pfx,
 		      int mode, myf MyFlags);

=== modified file 'Percona-Server/mysys/mf_cache.c'
--- Percona-Server/mysys/mf_cache.c	2011-06-30 15:46:53 +0000
+++ Percona-Server/mysys/mf_cache.c	2012-10-26 05:11:24 +0000
@@ -119,3 +119,21 @@
   }
   DBUG_VOID_RETURN;
 }
+
+/*
+  Truncate the cached file to a given offset. The cache must be reinitialized
+  with reinit_io_cache() after this call.
+*/
+
+my_bool truncate_cached_file(IO_CACHE *cache, my_off_t pos)
+{
+  DBUG_ENTER("truncate_cached_file");
+
+  if (my_b_inited(cache) && cache->file > -1)
+  {
+    if (my_chsize(cache->file, pos, 0, MYF(MY_WME)))
+      DBUG_RETURN(TRUE);
+  }
+
+  DBUG_RETURN(FALSE);
+}

=== modified file 'Percona-Server/sql/log.cc'
--- Percona-Server/sql/log.cc	2012-10-17 03:47:45 +0000
+++ Percona-Server/sql/log.cc	2012-10-26 05:11:24 +0000
@@ -395,6 +395,11 @@
       delete pending();
       set_pending(0);
     }
+    /*
+      Truncate the temporary file to reclaim disk space occupied by cached
+      transactions on COMMIT/ROLLBACK.
+    */
+    truncate_cached_file(&cache_log, pos);
     reinit_io_cache(&cache_log, WRITE_CACHE, pos, 0, 0);
     cache_log.end_of_file= saved_max_binlog_cache_size;
   }