Re: wal-debug

From: "Munteanu Gabriel" <gmunteanu(at)rdslink(dot)ro>
To: "Martijn van Oosterhout" <kleptog(at)svana(dot)org>
Cc: "postgres-general" <pgsql-general(at)postgresql(dot)org>
Subject: Re: wal-debug
Date: 2003-03-03 21:46:39
Message-ID: 00a101c2e1ce$5f821b70$4b5ae73e@SERVERXP
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in the URL you sent me, i read the following:
Write Ahead Logging (WAL) is a standard approach to transaction logging. Its
detailed description may be found in most (if not all) books about
transaction processing. Briefly, WAL's central concept is that changes to
data files (where tables and indexes reside) must be written only after
those changes have been logged - that is, when log records have been flushed
to permanent storage. When we follow this procedure, we do not need to flush
data pages to disk on every transaction commit, because we know that in the
event of a crash we will be able to recover the database using the log: any
changes that have not been applied to the data pages will first be redone
from the log records (this is roll-forward recovery, also known as REDO) and
then changes made by uncommitted transactions will be removed from the data
pages (roll-backward recovery - UNDO).

So, WAL is about logging. it logs every transaction that is made to the
database.

I want to disable logging of the transactions.

i don't need undo' s and redo's. I don't want to know if someone has
inserted something in the databse or not. AND, ESPECIALLY, i don't want any
other writing in RAM or later on disk because of the logging. (WAL
introduces an overhead, it writes in a buffer in RAM some data about the
transactions and when the buffer is full or some other event occurs it
writes it to disk).

I am not doing something specially, I want to increase performance, that's
all.

and wanted to disable WAL.

----- Original Message -----
From: "Martijn van Oosterhout" <kleptog(at)svana(dot)org>
To: "Munteanu Gabriel" <gmunteanu(at)rdslink(dot)ro>
Cc: "postgres-general" <pgsql-general(at)postgresql(dot)org>
Sent: Monday, March 03, 2003 2:28 PM
Subject: Re: [GENERAL] wal-debug

Please read this:

http://www.postgresql.org/docs/view.php?version=7.3&idoc=1&file=wal.html

The upshot that it doesn't need to write as much to disk to commit a
transaction and those write are sequential instead of scattered across the
disk.

What are you doing that makes you think WAL is bad?

In response to

  • Re: wal-debug at 2003-03-03 22:28:39 from Martijn van Oosterhout

Responses

  • Re: wal-debug at 2003-03-04 00:00:36 from Martijn van Oosterhout
  • Re: wal-debug at 2003-03-04 07:06:45 from Shridhar Daithankar<shridhar_daithankar@persistent.co.in>

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