Re: [HACKERS] possible new option for wal_sync_method

2012-03-02 Thread Dan Scales
the trick of flushing the disk cache. Dan - Original Message - From: Andres Freund and...@anarazel.de To: pgsql-hackers@postgresql.org Cc: Dan Scales sca...@vmware.com Sent: Monday, February 27, 2012 12:43:49 PM Subject: Re: [HACKERS] possible new option for wal_sync_method Hi

[HACKERS] possible new option for wal_sync_method

2012-02-16 Thread Dan Scales
When running Postgres on a single ext3 filesystem on Linux, we find that the attached simple patch gives significant performance benefit (7-8% in numbers below). The patch adds a new option for wal_sync_method, which is open_direct. With this option, the WAL is always opened with O_DIRECT (but

Re: [HACKERS] possible new option for wal_sync_method

2012-02-16 Thread Dan Scales
: Andres Freund and...@anarazel.de To: pgsql-hackers@postgresql.org Cc: Dan Scales sca...@vmware.com Sent: Thursday, February 16, 2012 10:32:09 AM Subject: Re: [HACKERS] possible new option for wal_sync_method Hi, On Thursday, February 16, 2012 06:18:23 PM Dan Scales wrote: When running Postgres

Re: [HACKERS] double writes using double-write buffer approach [WIP]

2012-02-08 Thread Dan Scales
...@postgresql.org [mailto:pgsql-hackers-ow...@postgresql.org] On Behalf Of Dan Scales Sent: Saturday, January 28, 2012 4:02 AM To: PG Hackers Subject: [HACKERS] double writes using double-write buffer approach [WIP] I've been prototyping the double-write buffer idea that Heikki and Simon had proposed

Re: [HACKERS] double writes using double-write buffer approach [WIP]

2012-02-06 Thread Dan Scales
were in use, they might be automatically switched over to full page writes for the duration of the base backup. And the double write file should not be part of the base backup. Dan - Original Message - From: Fujii Masao masao.fu...@gmail.com To: Dan Scales sca...@vmware.com Cc: PG Hackers

Re: [HACKERS] double writes using double-write buffer approach [WIP]

2012-02-05 Thread Dan Scales
on. Thanks, Dan - Original Message - From: Robert Haas robertmh...@gmail.com To: Dan Scales sca...@vmware.com Cc: PG Hackers pgsql-hackers@postgresql.org Sent: Friday, February 3, 2012 1:48:54 PM Subject: Re: [HACKERS] double writes using double-write buffer approach [WIP] On Fri, Feb 3

Re: [HACKERS] double writes using double-write buffer approach [WIP]

2012-02-03 Thread Dan Scales
Message - From: Robert Haas robertmh...@gmail.com To: Dan Scales sca...@vmware.com Cc: PG Hackers pgsql-hackers@postgresql.org Sent: Thursday, February 2, 2012 7:19:47 AM Subject: Re: [HACKERS] double writes using double-write buffer approach [WIP] On Fri, Jan 27, 2012 at 5:31 PM, Dan Scales

Re: [HACKERS] 16-bit page checksums for 9.2

2012-01-27 Thread Dan Scales
calculation (PageSetVerificationInfo) to mdextend() (or preferably smgrextend()) as well? Otherwise, you won't be checksumming a bunch of the new pages. Dan - Original Message - From: Robert Haas robertmh...@gmail.com To: Dan Scales sca...@vmware.com Cc: Noah Misch n...@leadboat.com, Heikki

Re: [HACKERS] 16-bit page checksums for 9.2

2012-01-26 Thread Dan Scales
Some other comments on the checksum patch: I'm not sure why you moved the checksum calculation (PageSetVerificationInfo) to mdwrite() rather than smgrwrite(). If there were every another storage backend, it would have to duplicate the checksum check, right? Is there a disadvantage to putting

Re: [HACKERS] [WIP] Double-write with Fast Checksums

2012-01-17 Thread Dan Scales
all comments/suggestions. Thanks, Dan - Original Message - From: Dan Scales sca...@vmware.com To: Heikki Linnakangas heikki.linnakan...@enterprisedb.com Cc: PG Hackers pgsql-hackers@postgresql.org, jks...@gmail.com, David Fetter da...@fetter.org Sent: Wednesday, January 11, 2012 1:25:21

Re: [HACKERS] [WIP] Double-write with Fast Checksums

2012-01-11 Thread Dan Scales
Thanks for all the comments and suggestions on the double-write patch. We are working on generating performance results for the 9.2 patch, but there is enough difference between 9.0 and 9.2 that it will take some time. One thing in 9.2 that may be causing problems with the current patch is the