Horton

Re: regression, deadlock in high frequency single-row UPDATE

Mark Kirkwood <mark.kirkwood@catalyst.net.nz>

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From: Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Andrew Sackville-West <awest@janrain.com>, pgsql-bugs@postgresql.org, Paulo Tanimoto <paulo@janrain.com>
Date: 2014-12-14T02:22:01Z
Lists: pgsql-bugs 
On 13/12/14 10:57, Alvaro Herrera wrote:
> Alvaro Herrera wrote:
>> Alvaro Herrera wrote:
>>
>>> I'm going to experiment with that idea and see if it leads to a
>>> solution.  I tried the other idea yesterday (to keep the HW tuple lock
>>> we acquire in heap_lock_tuple until heap_update is done) but aside from
>>> being very complicated and bug-prone, it doesn't solve the problem
>>> anyway.
>>
>> Here's a preliminary patch.
>
> Here's a finished version of this patch, which I messed a bit with and
> so needs some extra testing.  I want to push this shortly and backpatch
> to 9.4 and 9.3.  I don't want to disrupt the 9.4.0 release next week,
> but it'd be nice not to ship it with this bug.
>

This patch seems good too. I'm possibly seeing it performing slightly 
slower than the previous patch (approx 68 tps vs 63 on average - 
completely untuned 9.5 running on a single SATA drive, but that could 
just be natural variation/noise).

Regards

Mark

Commits

  1. Add isolationtester spec for old heapam.c bug

  2. Improve concurrency of foreign key locking