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Re: FSM rewrite committed, loose ends

From: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
To: Zdenek Kotala <Zdenek(dot)Kotala(at)Sun(dot)COM>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: FSM rewrite committed, loose ends
Date: 2008-10-02 08:07:14
Message-ID: 48E48132.9020502@enterprisedb.com (view raw or flat)
Thread:
Lists: pgsql-hackers
Zdenek Kotala wrote:
> Heikki Linnakangas napsal(a):
>> The FSM is not updated during WAL replay. That means that after crash 
>> recovery, the FSM won't be completely up-to-date, but at roughly the 
>> state it was at last checkpoint. In a warm stand-by, the FSM will 
>> reflect the situation at last full backup. We need to think when the 
>> FSM should be updated during WAL replay. Probably not after every 
>> record, because of the overhead, but certainly more often than never.
> 
> What's about after a page write  during a WAL replay?

You mean when a page is evicted from the buffer cache? That might be 
pretty good from performance point of view, but from a modularity point 
of view, the buffer manager should have no business modifying the FSM.

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

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