Re: unlogged tables - Mailing list pgsql-hackers

From Tom Lane
Subject Re: unlogged tables
Date
Msg-id 16060.1290019606@sss.pgh.pa.us
Whole thread Raw
In response to Re: unlogged tables  (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>)
Responses Re: unlogged tables
List pgsql-hackers
Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> writes:
> On 17.11.2010 17:11, Tom Lane wrote:
>> The objection to that was not about performance.  It was about how
>> to find out what needs to be fsync'd.

> I must be missing something: we handle that just fine with normal 
> tables, why is it a problem for unlogged tables?

Hmm ... that's a good point.  If we simply treat unlogged tables the
same as regular for checkpointing purposes, don't we end up having
flushed them all correctly during a shutdown checkpoint?  I was thinking
that WAL-logging had some influence on that logic, but it doesn't.

Robert is probably going to object that he wanted to prevent any
fsyncing for unlogged tables, but the discussion over in pgsql-general
is crystal clear that people do NOT want to lose unlogged data over
a clean shutdown and restart.  If all it takes to do that is to refrain
from lobotomizing the checkpoint logic for unlogged tables, I say we
should refrain.
        regards, tom lane


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