Re: [HACKERS] More benchmarking of wal_buffers

2003-02-13 Thread Tom Lane
"Christopher Kings-Lynne" <[EMAIL PROTECTED]> writes: > Here's a question then - what is the _drawback_ to having 1024 wal_buffers > as opposed to 8? Waste of RAM? You'd be better off leaving that 8 meg available for use as general-purpose buffers ... regards, tom lane -

Re: [HACKERS] More benchmarking of wal_buffers

2003-02-13 Thread Christopher Kings-Lynne
> I don't think this is based on a useful test for wal_buffers. The > wal_buffers setting only has to be large enough for the maximum amount > of WAL log data that your system emits between commits, because a commit > (from anyone) is going to flush the WAL data to disk (for everyone). > So a benc

Re: [HACKERS] More benchmarking of wal_buffers

2003-02-13 Thread Christopher Kings-Lynne
> I don't think this is based on a useful test for wal_buffers. The > wal_buffers setting only has to be large enough for the maximum amount > of WAL log data that your system emits between commits, because a commit > (from anyone) is going to flush the WAL data to disk (for everyone). > So a benc

Re: [HACKERS] More benchmarking of wal_buffers

2003-02-13 Thread Tom Lane
"Christopher Kings-Lynne" <[EMAIL PROTECTED]> writes: > I've just spent the last day and a half trying to benchmark our new database > installation to find a good value for wal_buffers. The quick answer - there > isn't, just leave it on the default of 8. I don't think this is based on a useful te

Re: [HACKERS] More benchmarking of wal_buffers

2003-02-12 Thread Neil Conway
On Thu, 2003-02-13 at 00:16, Christopher Kings-Lynne wrote: > Even if you look at the attached charts and you think that 128 buffers are > better than 8, think again - there's nothing in it. Next time I run that > benchmark it could be the same, lower or higher. And the difference between > the w

Re: [HACKERS] More benchmarking of wal_buffers

2003-02-12 Thread Bruce Momjian
Christopher Kings-Lynne wrote: > I'm not sure what I could test next. Does FreeBSD support anything other > than fsync? eg. fdatasync, etc. I can't see it in the man pages... You are already getting the best default for your OS. It say 'fsync' for default, but the comment says the default is O