Re: synchronous_commit off - Mailing list pgsql-performance

From Craig Ringer
Subject Re: synchronous_commit off
Date
Msg-id 4E373B77.8060001@postnewspapers.com.au
Whole thread Raw
In response to Re: synchronous_commit off  (Greg Smith <greg@2ndQuadrant.com>)
List pgsql-performance
On 2/08/2011 3:52 AM, Greg Smith wrote:
On 08/01/2011 09:29 AM, Anibal David Acosta wrote:

Can a transaction committed asynchronously report an error, duplicate key or something like that, causing a client with a OK transaction but server with a FAILED transaction.


No.  You are turning off the wait for the transaction to hit disk before returning to the client, but all the validation checks are done before that.  The sole risk with synchronous_commit off is that a client will get COMMIT, but the server will lose the transaction completely--when there's a crash before it's written to disk.

What about an I/O error during write, or other HW-level issues that might cause a transaction to fail to commit while others proceed fine?

--
Craig Ringer

POST Newspapers 276 Onslow Rd, Shenton Park Ph: 08 9381 3088 Fax: 08 9388 2258 ABN: 50 008 917 717 http://www.postnewspapers.com.au/

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