Re: test_fsync open_sync test - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: test_fsync open_sync test
Date
Msg-id 201101181644.p0IGiv508938@momjian.us
Whole thread Raw
In response to Re: test_fsync open_sync test  (Greg Smith <greg@2ndquadrant.com>)
List pgsql-hackers
Greg Smith wrote:
> Bruce Momjian wrote:
> > Is there a value to this test_fsync test?
> >
> >     Compare open_sync with different sizes:
> >     (This is designed to compare the cost of one large
> >     sync'ed write and two smaller sync'ed writes.)
> >             open_sync 16k write               242.563 ops/sec
> >             2 open_sync 8k writes             752.752 ops/sec
> >
> > It compares the cost of doing larger vs. two smaller open_sync writes.
> >   
> 
> Might be some value for determining things like what the optimal WAL 
> block size to use is.  All these tests are kind of hard to use 
> effectively still, I'm not sure if it's time to start trimming tests yet 
> until we've made more progress on interpreting results first.

OK, thanks for the feedback.  I just wanted to make sure it wasn't a
stupid test.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +


pgsql-hackers by date:

Previous
From: Robert Haas
Date:
Subject: Re: ToDo List Item - System Table Index Clustering
Next
From: Robert Haas
Date:
Subject: Re: texteq/byteaeq: avoid detoast [REVIEW]