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From:Satya B Date:March 20 2009 9:18am
Subject:bzr commit into mysql-5.0-bugteam branch (satya.bn:2745) Bug#41330
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#At file:///home/satya/WORK/mysql-5.0-bugteam-41330/ based on revid:davi.arnaut@stripped

 2745 Satya B	2009-03-20
      Fix for BUG#41330 -Myisam table open count set to zero before index blocks 
                         are written.
            
      When we have a myisam table with DELAY_KEY_WRITE option, index updates
      are not applied until the flush tables command is issued or until the
      server is shutdown. If server gets killed before the index updates are 
      written to disk, the index file is corrupted as expected but the table 
      is not marked as crashed. So when we start server with myisam-recover,
      table is not repaired leaving the table unusable.
            
      The problem is when we try to write the index updates to index file,
      we decrement the open_count even before the flushing the keys to index
      file.
            
      Fixed by moving the decrement operation after flushing the keys to the
      index file. So we always have non zero open count if the flush table
      operation is killed and when the server is started with mysiam-recover
      option, it marks the table as crashed and repairs it.
            
      Note: No testcase for added as we need to kill the server and start the 
            server with different set of options and other non trivial
            operations involved.
      modified:
        myisam/mi_close.c

per-file messages:
  myisam/mi_close.c
    Decrement open count after flushing the key blocks to the
    key file. If the server(with DELAY_KEY_WRITE option) is
    killed before flush_key_blocks operation, we will have non
    zero open count and the table can be repaired when server is
    started with --myisam-recover option.
=== modified file 'myisam/mi_close.c'
--- a/myisam/mi_close.c	2007-03-28 17:46:42 +0000
+++ b/myisam/mi_close.c	2009-03-20 09:18:14 +0000
@@ -35,8 +35,6 @@ int mi_close(register MI_INFO *info)
   if (info->lock_type == F_EXTRA_LCK)
     info->lock_type=F_UNLCK;			/* HA_EXTRA_NO_USER_CHANGE */
 
-  if (share->reopen == 1 && share->kfile >= 0)
-    _mi_decrement_open_count(info);
 
   if (info->lock_type != F_UNLCK)
   {
@@ -78,6 +76,8 @@ int mi_close(register MI_INFO *info)
       */
       if (share->mode != O_RDONLY && mi_is_crashed(info))
 	mi_state_info_write(share->kfile, &share->state, 1);
+      /* Decrement open count must be last I/O on this file. */
+      _mi_decrement_open_count(info);
       if (my_close(share->kfile,MYF(0)))
         error = my_errno;
     }

Thread
bzr commit into mysql-5.0-bugteam branch (satya.bn:2745) Bug#41330Satya B20 Mar
  • Re: bzr commit into mysql-5.0-bugteam branch (satya.bn:2745) Bug#41330Sergey Vojtovich20 Mar
    • Re: bzr commit into mysql-5.0-bugteam branch (satya.bn:2745) Bug#41330satya20 Mar