Side effect of synchronous_commit = off
I was wondering whether setting synchronous_commit = off will have the following side effect.
(1) Process A issues UPDATE command on row x, from false to true.
(2) After that, Process B READ from row x.
Is it possible that when Process B start to read row x, the "true" value is not being "flushed" to the table. Hence, process B will read the row x as false?
If this situation will happen, is it possible that Process B may issues a command, use to "flush all" pending data to be written to disk?
Thanks and Regards
Yan Cheng CHEOK
Le 25/03/2010 08:49, Yan Cheng CHEOK a �crit :
I was wondering whether setting synchronous_commit = off will have the following side effect.
(1) Process A issues UPDATE command on row x, from false to true.
(2) After that, Process B READ from row x.Is it possible that when Process B start to read row x, the "true" value is not being "flushed" to the table. Hence, process B will read the row x as false?
No, it's not possible.
--
Guillaume.
http://www.postgresqlfr.org
http://dalibo.com
Being asynchronous, means that write-to-disk will be queued in kernel for
later execution, ie, postgresql won't wait for its write confirmation, but
they will occurr in a serial manner.
On Thu, Mar 25, 2010 at 4:49 AM, Yan Cheng CHEOK <yccheok@yahoo.com> wrote:
Show quoted text
I was wondering whether setting synchronous_commit = off will have the
following side effect.(1) Process A issues UPDATE command on row x, from false to true.
(2) After that, Process B READ from row x.Is it possible that when Process B start to read row x, the "true" value is
not being "flushed" to the table. Hence, process B will read the row x as
false?If this situation will happen, is it possible that Process B may issues a
command, use to "flush all" pending data to be written to disk?Thanks and Regards
Yan Cheng CHEOK--
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