Обсуждение: What is the role of #fsync and #synchronous_commit in configuration file .
What is the role of #fsync and #synchronous_commit in configuration file .
От
keshav upadhyaya
Дата:
Hi ,
I want to imporve the performance for inserting of huge data in my table .
I have only one idex in table .
First question - i want to know the role played by
#fsync = on and
#synchronous_commit = on
They are commented by default in 8.4 .
When made like this :-
fsync = off
synchronous_commit = off
It improve the performance :)
and query took less time .
I want to understand more in details what exactly had happened one is made them "off" , is it dangerous to do this ? as it will not sync the data in each commit .
Pls help me out .
--
Thanks,
Keshav Upadhyaya
I want to imporve the performance for inserting of huge data in my table .
I have only one idex in table .
First question - i want to know the role played by
#fsync = on and
#synchronous_commit = on
They are commented by default in 8.4 .
When made like this :-
fsync = off
synchronous_commit = off
It improve the performance :)
and query took less time .
I want to understand more in details what exactly had happened one is made them "off" , is it dangerous to do this ? as it will not sync the data in each commit .
Pls help me out .
--
Thanks,
Keshav Upadhyaya
Re: What is the role of #fsync and #synchronous_commit in configuration file .
От
Josh Kupershmidt
Дата:
On Tue, Oct 6, 2009 at 3:28 AM, keshav upadhyaya <ukeshav2009@gmail.com> wrote: > First question - i want to know the role played by > > #fsync = on and > #synchronous_commit = on These configurations are discussed here: http://developer.postgresql.org/pgdocs/postgres/runtime-config-wal.html > I want to understand more in details what exactly had happened one is made > them "off" , is it dangerous to do this ? as it will not sync the data in > each commit . > There's plenty of discussion in the documentation and the list archives about the risks of disabling fsync and/or synchronous commit. Here's one: http://archives.postgresql.org/pgsql-performance/2006-04/msg00631.php If you're struggling with performance issues, I'd post a detailed description of your problem and what you've tried so far to the -performance list, instead of turning fsync off. Josh