| From: | Peter Geoghegan <pg(at)heroku(dot)com> |
|---|---|
| To: | Kevin Grittner <kgrittn(at)ymail(dot)com> |
| Cc: | Andres Freund <andres(at)2ndquadrant(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>, Craig Ringer <craig(at)2ndquadrant(dot)com> |
| Subject: | Re: INSERT ... ON CONFLICT {UPDATE | IGNORE} |
| Date: | 2014-09-29 22:21:30 |
| Message-ID: | CAM3SWZSmn90B_QQC2XcVuT=ceTtW9Y4rYmfi7MAh=nQg9g-U5g@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Mon, Sep 29, 2014 at 3:08 PM, Kevin Grittner <kgrittn(at)ymail(dot)com> wrote:
> Well, unless we abandon transactional semantics for other MERGE
> statements, we should have a way that UPSERT logic continues to
> work if you don't match a suitable index; it will just be slower --
> potentially a lot slower, but that's what indexes are for.
I want an implementation that doesn't have unique violations,
unprincipled deadlocks, or serialization failures at READ COMMITTED. I
want it because that's what the majority of users actually want. It
requires no theoretical justification.
> I don't
> think we need a separate statement type for the one we "do well",
> because I don't think we should do the other one without proper
> transactional semantics.
That seems like a very impractical attitude. I cannot simulate what
I've been doing with unique indexes without taking an exclusive table
lock. That is a major footgun, so it isn't going to happen.
--
Peter Geoghegan
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