Re: Side effect of synchronous_commit = off - Mailing list pgsql-general

From Arthur Turrini
Subject Re: Side effect of synchronous_commit = off
Date
Msg-id 7308d4541003291146x25be13c1jc9098f3820e90614@mail.gmail.com
Whole thread Raw
In response to Side effect of synchronous_commit = off  (Yan Cheng CHEOK <yccheok@yahoo.com>)
List pgsql-general
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:
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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