On 01/03/2015 10:42 PM, Peter Geoghegan wrote:
On Sat, Jan 3, 2015 at 2:41 AM, Heikki Linnakangas
wrote:
A-ha, I see. And this can happen without INSERT ON CONFLICT, too? In that
case, one of the transactions is bound to error and roll back anyway, but
you get a deadlock error instead of the co
On Mon, Jan 5, 2015 at 5:53 PM, Peter Geoghegan wrote:
> It's not all that easy to recreate, even with my custom
> instrumentation. With fsync=off, it occurs somewhat infrequently with
> a custom instrumentation Postgres build:
>
> pg@hamster:~/jjanes_upsert$ perl count_upsert.pl 8 10
> [Mon J
On Thu, Jan 1, 2015 at 11:17 PM, Peter Geoghegan wrote:
> The attached patch fixes Jeff's test case, as far as it goes. But, as
> I mentioned, it's not intended as a real fix. For one thing, I have
> made multiple changes to HeapTupleSatisfies*() routines, but haven't
> fully considered the conseq
On Sat, Jan 3, 2015 at 10:16 PM, Peter Geoghegan wrote:
> I looked at the code in more detail, and realized that there were old
> bugs in the exclusion constraint related modifications. I attach a
> delta patch that fixes them. This is a combined patch that is all that
> is needed to apply on top
On Sat, Jan 3, 2015 at 12:42 PM, Peter Geoghegan wrote:
> There are probably additional factors that make the situation more
> complicated than it is for the ON CONFLICT patch, but it's clear to me
> that the mutual dependency that can be involved with two ordinary
> exclusion constraint inserters
On Sat, Jan 3, 2015 at 2:41 AM, Heikki Linnakangas
wrote:
> A-ha, I see. And this can happen without INSERT ON CONFLICT, too? In that
> case, one of the transactions is bound to error and roll back anyway, but
> you get a deadlock error instead of the constraint violation error, which is
> not as
On 01/03/2015 12:00 PM, Peter Geoghegan wrote:
Two concurrent exclusion constraints inserters can easily insert at
exactly the same time, and then wait on each other's xact, and then
deadlock. That can't happen with B-Tree inserts because the checking
and insertion happen at the same time, when t
On Sat, Jan 3, 2015 at 1:29 AM, Heikki Linnakangas
wrote:
> Please explain in words of one syllable how the deadlock arises. Then,
> please find a way to fix it.
I believe that the deadlock arises because there is no choke point.
Exclusion constraint insertions always insert first, then check for
On 01/03/2015 02:43 AM, Peter Geoghegan wrote:
On Thu, Jan 1, 2015 at 11:17 PM, Peter Geoghegan wrote:
I've been working on fixing the bugs that Jeff Janes found [1] with
approach #2 to value locking [2]. Approach #1 was unaffected.
Unfortunately, exclusion constraints (which only value locki
On Thu, Jan 1, 2015 at 11:17 PM, Peter Geoghegan wrote:
> I've been working on fixing the bugs that Jeff Janes found [1] with
> approach #2 to value locking [2]. Approach #1 was unaffected.
Unfortunately, exclusion constraints (which only value locking
approach #2 has support for, for the IGNORE
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