Bug #39025 Falcon writes key pages to Serial Log in wrong order.

• Submitted: 26 Aug 2008 0:05
• Modified: 18 Oct 2008 16:58
• Reporter: Kevin Lewis
• Status: Closed
• Category: Server: Falcon
• Severity: S3 (Non-critical)
• Version: 6.0.7
• OS: Any
• Assigned to: Kevin Lewis
• Target Version: 6.0-beta
• Tags: Serial Log
• Triage: D2 (Serious)

[26 Aug 2008 0:05] Kevin Lewis

Description:
During a Falcon show-and-tell session at the Boston meeting in July, Jim noticed that the
parent, right, and left key pages affected by a page split are written to the serial log
in the wrong order.  This could cause a problem only if a failure occurred during a
recovery in the middle of rewriting these three pages.  The chance of this happening is
very low and cannot be tested deterministically.

How to repeat:
Difficult to repeat

Suggested fix:
Write the 3 pages to the serial log in this order; 
1) The new right page first,
2) then the previously existing left page (which is now half full), 
3) then the parent page.

[26 Aug 2008 0:06] Kevin Lewis

Verified in the code.

[26 Aug 2008 0:09] Bugs System

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/52508

2800 Kevin Lewis	2008-08-25
      Bug#39025 Wrte pages to the serial log in this order;
      1) The new right page first,
      2) then the previously existing left page (which is now half full), 
      3) then the parent page

[26 Aug 2008 6:48] Bugs System

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/52519

2800 Kevin Lewis	2008-08-25
      Bug#39025 Wrte pages to the serial log in this order;
      1) The new right page first,
      2) then the previously existing left page (which is now half full), 
      3) then the parent page

[28 Aug 2008 6:28] Bugs System

Pushed into 6.0.7-alpha  (revid:[e-mail]-20080825220913-bcgsb6u07nnbbopq) (version
source revid:[e-mail]-20080827094944-sh582y3m7duhzrpj) (pib:3)

[14 Sep 2008 6:14] Bugs System

Pushed into 6.0.7-alpha  (revid:[e-mail]-20080825220913-bcgsb6u07nnbbopq) (version
source revid:[e-mail]-20080721095625-h2pyxb88uwtjeavf) (pib:3)

[18 Oct 2008 16:58] Jon Stephens

Documented in the 6.0.7 changelog as follows:

        Falcon key pages were written to the serial log in the wrong order. This
        has the potential to cause problems if a failure of the server occurred
        during recovery.

[20 Nov 2008 13:56] Bugs System

Pushed into 6.0.9-alpha  (revid:[e-mail]-20081103175136-mxc2c678yiebrep3)
(version source revid:[e-mail]-20081105154145-9cymy8nzucy8efig) (pib:5)