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Re: synchronous_commit and mvcc - Mailing list pgsql-general

From Andy Colson
Subject Re: synchronous_commit and mvcc
Date
Msg-id 4A831AC3.4010702@squeakycode.net
Whole thread Raw
In response to synchronous_commit and mvcc  (Kelly Burkhart <kelly.burkhart@gmail.com>)
List pgsql-general
Kelly Burkhart wrote:
> Hello,
>
> We have synchronous_commit=off in our postgresql.conf file.  Does this
> setting affect mvcc?  For instance if I have two connections from
> processes on different machines that do the following:
>
> c1 begins transaction
> c1 inserts rows into table
> c1 commits transaction
> c2 begins transaction
> c2 queries table
>
> At this point, is it possible that c2 is not able to see the rows from
> connection 1 that were inserted and committed prior to the c2
> transaction starting?
>
> Thanks,
>
> -K


 > Does this setting affect mvcc?

No, only how its saved to disk.  Clients will see no difference.

But transaction isolation can mess with it:

http://www.postgresql.org/docs/8.3/static/transaction-iso.html

-Andy

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