Re: New FSM patch - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: New FSM patch
Date
Msg-id 48C0F220.30002@enterprisedb.com
Whole thread Raw
In response to Re: New FSM patch  (Simon Riggs <simon@2ndQuadrant.com>)
List pgsql-hackers
Simon Riggs wrote:
> On Thu, 2008-09-04 at 11:07 +0300, Heikki Linnakangas wrote:
>> Scenario: The binary tree on a page is corrupt, so that the value of an 
>> upper node is > Max(leftchild, rightchild).
>> Consequence: Searchers will notice the corruption while trying to 
>> traverse down that path, and throw an elog(WARNING) in search_avail(). 
>> fsm_search will retry the search, and will in worst case go into an 
>> infinite loop. That's obviously not good. We could automatically fix the 
>> upper nodes of the tree, but that would wipe evidence that would be 
>> useful in debugging.
> 
> We probably need to break out of infinite loops, especially ones that
> output warning messages on each loop. :-)

Yep. I turned that warning into an error in the latest patch I just 
posted elsewhere in this thread.

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com


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