Horton

Re: SSI non-serializable UPDATE performance

Simon Riggs <simon@2ndquadrant.com>

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From: Simon Riggs <simon@2ndQuadrant.com>
To: Dan Ports <drkp@csail.mit.edu>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2011-04-27T17:26:52Z
Lists: pgsql-hackers

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  1. Add fast paths for cases when no serializable transactions are running.

On Mon, Apr 25, 2011 at 4:33 AM, Dan Ports <drkp@csail.mit.edu> wrote:
> On Sat, Apr 23, 2011 at 08:54:31AM -0500, Kevin Grittner wrote:
>> Even though this didn't show any difference in Dan's performance
>> tests, it seems like reasonable insurance against creating a new
>> bottleneck in very high concurrency situations.
>>
>> Dan, do you have a patch for this, or should I create one?
>
> Sure, patch is attached.


Reading the code, IIUC, we check for RW conflicts after each write but
only if the writer is running a serializable transaction.

Am I correct in thinking that there is zero impact of SSI if nobody is
running a serializable transaction?


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