Message-ID: <496F5CD5.3010300@enterprisedb.com>
Date: Thu, 15 Jan 2009 17:57:09 +0200
From: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Organization: EnterpriseDB
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To: Bruce Momjian <bruce@momjian.us>
CC: Gregory Stark <stark@enterprisedb.com>,
	PostgreSQL-development <pgsql-hackers@postgresql.org>,
	Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: Visibility map, partial vacuums
References: <200901151548.n0FFmr204820@momjian.us>
In-Reply-To: <200901151548.n0FFmr204820@momjian.us>
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Bruce Momjian wrote:
> Heikki Linnakangas wrote:
>>>> Also, is anything being done about the concern about 'vacuum storm'
>>>> explained below?
>>> I'm interested too.
>> The additional "vacuum_freeze_table_age" (as I'm now calling it) setting 
>> I discussed in a later thread should alleviate that somewhat. When a 
>> table is autovacuumed, the whole table is scanned to freeze tuples if 
>> it's older than vacuum_freeze_table_age, and relfrozenxid is advanced. 
>> When different tables reach the autovacuum threshold at different times, 
>> they will also have their relfrozenxids set to different values. And in 
>> fact no anti-wraparound vacuum is needed.
>>
>> That doesn't help with read-only or insert-only tables, but that's not a 
>> new problem.
> 
> OK, is this targeted for 8.4?

Yes. It's been on my todo list for a long time, and I've also added it 
to the Open Items list so that we don't lose track of it.

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