Обсуждение: What is the role of #fsync and #synchronous_commit in configuration file .

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

>From: keshav upadhyaya
>Subject: [PERFORM] What is the role of #fsync and #synchronous_commit in
configuration file .
>
>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
>
>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 .


The settings are described in the docs:

http://www.postgresql.org/docs/8.4/interactive/runtime-config-wal.html

If you turn fsync off, you risk data loss in case of power or hardware
failure.

Dave