Re: WAL logging volume and CREATE TABLE

Bruce Momjian <bruce@momjian.us>

From: Bruce Momjian <bruce@momjian.us>
To: Alvaro Herrera <alvherre@commandprompt.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2011-08-03T18:52:01Z
Lists: pgsql-hackers

Attachments

Alvaro Herrera wrote:
> Excerpts from Bruce Momjian's message of mar ago 02 22:46:55 -0400 2011:
> 
> > I have created a documentation patch to clarify this, and to mention
> > CREATE TABLE AS which also has this optimization.
> 
> It doesn't seem particularly better to me.  How about something like
> 
> In minimal level, WAL-logging of some operations can be safely skipped,
> which can make those operations much faster (see <blah>).  Operations on
> which this optimization can be applied include: 
> <simplelist>
>  <item>CREATE INDEX</item>
>  <item>CLUSTER</item>
>  <item>CREATE TABLE AS</item>
>  <item>COPY, when tables that were created or truncated in the same
>  transaction
> </simplelist>
> 
> Minimal WAL does not contain enough information to reconstruct the data
> from a base backup and the WAL logs, so either <literal>archive</> or
> <literal>hot_standby</> level must be used to enable ...

Good idea --- updated patch attached.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +