Re: Will modifications to unlogged tables also be flused to disk?

From: Clemens Eisserer <linuxhippy(at)gmail(dot)com>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: Will modifications to unlogged tables also be flused to disk?
Date: 2014-02-15 11:38:33
Message-ID: CAFvQSYTcbv5TpC1Q8JMCG5sh6eZmDVoyL9qQ3PTW0DTzsYwMzA@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

Hi Vik,

> Yes. The only difference between logged and unlogged tables is the lack
> of WAL. As long as there's no crash, unlogged tables are treated the
> same as logged tables as far as flushing/fsync-ing is concerned.

Ok thats really bad news :/
After reading the discussion about calling unlogged tables "in memory"
or "cached" I actually had high hopes pgql would take advantage of the
fact that data of unlogged tables are not preserved at recovery.

However, it seems pgsql fsyncs frequently to guarantee durability of
table data which will be rejected anyway at recovery from an unclean
shutdown.

I'll have a look at the source and probably prepare a patch.

Regards, Clemens

In response to

Responses

Browse pgsql-general by date

  From Date Subject
Next Message Andres Freund 2014-02-15 11:47:57 Re: Will modifications to unlogged tables also be flused to disk?
Previous Message Vik Fearing 2014-02-15 11:26:57 Re: Will modifications to unlogged tables also be flused to disk?