Re: Summary and Plan for Hot Standby - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: Summary and Plan for Hot Standby
Date
Msg-id 4B003C34.4080604@enterprisedb.com
Whole thread Raw
In response to Re: Summary and Plan for Hot Standby  (Simon Riggs <simon@2ndQuadrant.com>)
Responses Re: Summary and Plan for Hot Standby
List pgsql-hackers
Simon Riggs wrote:
> On Sun, 2009-11-15 at 16:07 +0200, Heikki Linnakangas wrote:
> 
>> The assumption that b-tree vacuum records don't need conflict
>> resolution because we did that with the additional cleanup-info record
>> works ATM, but it hinges on the fact that we don't delete any tuples
>> marked as killed while we do the vacuum. 
> 
>> That seems like a low-hanging
>> fruit that I'd actually like to do now that I spotted it, but will
>> then need to fix b-tree vacuum records accordingly. We'd probably need
>> to do something about the previous item first to keep performance
>> acceptable.
> 
> We can optimise that by using the xlog pointer of the HeapInfo record.
> Any blocks cleaned that haven't been further updated can avoid
> generating further btree deletion records.

Sorry, I don't understand that. (Remember that marking index tuples as
killed is not WAL-logged.)

> You spotted this issue only this morning??

Yesterday evening.

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


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