Re: Improving compressibility of WAL files - Mailing list pgsql-hackers

From Aidan Van Dyk
Subject Re: Improving compressibility of WAL files
Date
Msg-id 20090109172938.GM12094@yugib.highrise.ca
Whole thread Raw
In response to Re: Improving compressibility of WAL files  (Richard Huxton <dev@archonet.com>)
Responses Re: Improving compressibility of WAL files  (Richard Huxton <dev@archonet.com>)
List pgsql-hackers
* Richard Huxton <dev@archonet.com> [090109 12:22]:

> > Yeah: the archiver process doesn't have that information available.

> Am I being really dim here - why isn't the first record in the WAL file
> a fixed-length record containing e.g. txid_start, time_start, txid_end,
> time_end, length? Write it once when you start using the file and once
> when it's finished.

It would break the WAL "write-block/sync-block" forward only progress of
the xlog, which avoids the whole torn-page problem that the heap has.

a.
-- 
Aidan Van Dyk                                             Create like a god,
aidan@highrise.ca                                       command like a king,
http://www.highrise.ca/                                   work like a slave.

pgsql-hackers by date:

Previous
From: Richard Huxton
Date:
Subject: Re: Improving compressibility of WAL files
Next
From: Heikki Linnakangas
Date:
Subject: Re: Hot standby, RestoreBkpBlocks and cleanup locks