Re: log chunking broken with large queries under load - Mailing list pgsql-hackers

From Tom Lane
Subject Re: log chunking broken with large queries under load
Date
Msg-id 29283.1333559683@sss.pgh.pa.us
Whole thread Raw
In response to Re: log chunking broken with large queries under load  (Andrew Dunstan <andrew@dunslane.net>)
Responses Re: log chunking broken with large queries under load  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Andrew Dunstan <andrew@dunslane.net> writes:
> On 04/04/2012 12:13 PM, Tom Lane wrote:
>> Does anyone feel that it's a bad idea that list entries are never
>> reclaimed?  In the worst case a transient load peak could result in
>> a long list that permanently adds search overhead.  Not sure if it's
>> worth the extra complexity to delete a list cell that's no longer
>> needed, rather than leaving it present and empty.

> Me either. The logic could possibly be something simple when we free a 
> node like "while the list tail is an available node prune the tail". But 
> as you say, it might not be worth it.

The idea I had in mind was to compensate for adding list-removal logic
by getting rid of the concept of an unused entry.  If the removal is
conditional then you can't do that and you end up with the complications
of both methods.  Anyway I've not tried to code it yet.
        regards, tom lane


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