Re: PostgreSQL win32 fragmentation issue - Mailing list pgsql-hackers

From Shane Ambler
Subject Re: PostgreSQL win32 fragmentation issue
Date
Msg-id 45723E9F.2080307@007Marketing.com
Whole thread Raw
In response to Re: PostgreSQL win32 fragmentation issue  ("Joshua D. Drake" <jd@commandprompt.com>)
List pgsql-hackers
Joshua D. Drake wrote:

> I am trying to get as much information as possible so that:
> 

Well I have a small postgresql setup on my girlfriends Win XP Pro 
machine that only had a little testing use a few months ago.

The data folder is 84MB and even though there is 25% total fragmentation 
and 45% file fragmentation on the drive - the largest being the 
pc-cillin log with 75,104 fragments - none of the fragmented files are 
postgresql data files. (Been a while since I defraged this)

If we stop and think about how windows (and mac os x) allocate file 
space as compared to *nix file systems then we can assume a few things 
that could be tested to verify.

The first test you mentioned you defraged with an existing db then ran 
the tests and then checked fragmentation again. Try this instead - 
remove the contents of the data folder - defrag - initdb - run test and 
see what fragmentation you get.

Try installing the data folder on a separate drive with nothing else on 
it and run the test and then look at fragmentation.

How about some performance tests to measure the difference between badly 
fragmented data files and un-fragmented data files. It may not make a 
significant difference.


-- 

Shane Ambler
pgSQL@007Marketing.com

Get Sheeky @ http://Sheeky.Biz


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