Re: WAL segments (names) not in a sequence

From: German Becker <german(dot)becker(at)gmail(dot)com>
To: Sergey Konoplev <gray(dot)ru(at)gmail(dot)com>
Cc: Amit Langote <amitlangote09(at)gmail(dot)com>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: WAL segments (names) not in a sequence
Date: 2013-05-23 13:18:53
Message-ID: CALyjCLvw-2z7SPApYj5ueXv_VSKJvMjvv=6AR+g6uLZQ8SNMGw@mail.gmail.com
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On Thu, May 23, 2013 at 5:29 AM, Sergey Konoplev <gray(dot)ru(at)gmail(dot)com> wrote:

> On Thu, May 23, 2013 at 1:25 AM, Amit Langote <amitlangote09(at)gmail(dot)com>
> wrote:
> > Okay, now I understand. Also, looking at his "ls -l pg_xlog", I could
> > find that modified timestamps of all those pre-allocated segments are
> > about similar (around 12:10), whereas the latest modified time (15:37)
> > is of segment 000000010000000E000000A7.
> >
> > Wonder if whatever configuration he is using is sub-optimal that these
> > many WAL segments can be re-cycled upon a checkpoint? Or is this okay?
>
> Is archive_mode=on?
> What is archive_command?
> Is the server in the recovery mode?
>
> --
> Kind regards,
> Sergey Konoplev
> PostgreSQL Consultant and DBA
>
> Profile: http://www.linkedin.com/in/grayhemp
> Phone: USA +1 (415) 867-9984, Russia +7 (901) 903-0499, +7 (988) 888-1979
> Skype: gray-hemp
> Jabber: gray(dot)ru(at)gmail(dot)com
>

Hi Sergey and all,
Let me describe the process I follow to get to this. What I am doing is
testing a migration from 8.3 to 9.1. They way I plan to do it is the
following.
1) Create the schema
2) import the biggest tables, which are not updated,only growing, with COPY
(this is about 35gb of data)
2)import the small, changing part of the data

The target system is 9.1 with streaming relication.
For steps 1 and 2, I set a "restore" configuration, that amongs other
things like more work mem, it sets archive_mode=off and wal_level=minimal
(attached the difference between restore and normal).
The archive_command is just a cp wrapped in a shell script in case I need
to change it.

Let me know if you need any more info

Attachment Content-Type Size
restorevsnormal.diff application/octet-stream 3.3 KB

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