bzr commit into mysql-backup-backport branch (ingo.struewing:3050) Bug#47484 WL#5101

[Ingo Struewing]

#At file:///home2/mydev/bzrroot/mysql-5.6-backup-backport-ms09-2/ based on revid:thavamuni.alagu@stripped

 3050 Ingo Struewing	2010-01-11
      WL#5101 - MySQL Backup back port
      Merged revid:ingo.struewing@stripped
        Bug#47484 - Online Backup: Restore does not
                  set the auto_increment value correctly
        
        When implementing the new locking scheme for RESTORE,
        the table's auto_increment values won't be restored.
        The new scheme contains TRUNCATE, which resets the
        auto_increment values to zero. This will lead to a
        "duplicate key" error on the next attempt to insert
        an auto_increment value, at least for the InnoDB
        storage engine.
        
        This patch arranges for a reset of the values to
        what they were at backup time. The auto_increment
        value of each table is stored at the end of the
        table data stream in its own chunk.
        
        Note that this is done for the default- and
        consistent snapshot drivers only. The MyISAM native
        driver restores the value on its own already.
        
        Note that there is a chance that the restored
        auto_increment value can be higher than at the
        validation point of BACKUP. Concurrent DML on a table
        backed up with the consistent snapshot driver can
        increase the auto_increment value before the driver
        reads it. Since we do not guarantee gap free
        auto_increment values, I consider this as acceptable.
        At least this patch assures that the values cannot be
        lower.
        
        Note that the patch does also contain a fix to the
        MEMORY storage engine. ha_heap::reset_auto_increment()
        assigned the value incorrectly. This has not been
        noticed yet because the only use case of the method
        was to reset the value to zero.
     @ storage/heap/ha_heap.cc
        WL#5101 - MySQL Backup back port
            Bug#47484 - Online Backup: Restore does not
                        set the auto_increment value correctly
            Fixed the value assignment to HP_SHARE::auto_increment
            in ha_heap::reset_auto_increment().
     @ storage/heap/hp_open.c
        WL#5101 - MySQL Backup back port
            Bug#47484 - Online Backup: Restore does not
                        set the auto_increment value correctly
            Added DBUG.

    modified:
      storage/heap/ha_heap.cc
      storage/heap/hp_open.c
=== modified file 'storage/heap/ha_heap.cc'
--- a/storage/heap/ha_heap.cc	2009-12-05 01:26:15 +0000
+++ b/storage/heap/ha_heap.cc	2010-01-11 15:31:28 +0000
@@ -406,7 +406,10 @@ int ha_heap::info(uint flag)
   stats.max_data_file_length= hp_info.max_records * hp_info.reclength;
   stats.delete_length=        hp_info.deleted * hp_info.reclength;
   if (flag & HA_STATUS_AUTO)
+  {
     stats.auto_increment_value= hp_info.auto_increment;
+    DBUG_PRINT("heap", ("autoinc: %lu", (ulong) stats.auto_increment_value));
+  }
   /*
     If info() is called for the first time after open(), we will still
     have to update the key statistics. Hoping that a table lock is now
@@ -447,7 +450,12 @@ int ha_heap::delete_all_rows()
 
 int ha_heap::reset_auto_increment(ulonglong value)
 {
-  file->s->auto_increment= value;
+  /*
+    The heap share holds the last used auto_increment value.
+    See heap_info() and ha_heap::create().
+  */
+  file->s->auto_increment= value ? value - 1 : 0;
+  DBUG_PRINT("heap", ("autoinc: %lu", (ulong) file->s->auto_increment));
   return 0;
 }
 

=== modified file 'storage/heap/hp_open.c'
--- a/storage/heap/hp_open.c	2009-12-05 01:26:15 +0000
+++ b/storage/heap/hp_open.c	2010-01-11 15:31:28 +0000
@@ -53,9 +53,11 @@ HP_INFO *heap_open_from_share(HP_SHARE *
 #ifndef DBUG_OFF
   info->opt_flag= READ_CHECK_USED;		/* Check when changing */
 #endif
-  DBUG_PRINT("exit",("heap: 0x%lx  reclength: %d  records_in_block: %d",
-		     (long) info, share->reclength,
-                     share->block.records_in_block));
+  DBUG_PRINT("exit",("heap: %p  reclength: %d  records_in_block: %d  "
+                     "autoinc: %lu",
+	             info, share->reclength,
+                     share->block.records_in_block,
+                     (ulong) share->auto_increment));
   DBUG_RETURN(info);
 }
 


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