Re: WIP: unique hash indexes - Mailing list pgsql-patches

From Bruce Momjian
Subject Re: WIP: unique hash indexes
Date
Msg-id 200312010455.hB14tUW17165@candle.pha.pa.us
Whole thread Raw
In response to WIP: unique hash indexes  (Neil Conway <neilc@samurai.com>)
Responses Re: WIP: unique hash indexes  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-patches
Your patch has been added to the PostgreSQL unapplied patches list at:

    http://momjian.postgresql.org/cgi-bin/pgpatches

I will try to apply it within the next 48 hours.

---------------------------------------------------------------------------


Neil Conway wrote:
> Attached is a patch that implements unique hash indexes. Regression
> tests and docs have been updated (with the exception of
> src/backend/access/hash/README).
>
> This patches implements an improved version of the concurrency changes I
> outlined on -hackers a couple days ago: the separate lock for
> "right-of-insertion" into a bucket chain has been replaced by making use
> of existing lmgr lockmodes to get the behavior we need.
>
> I also took the opportunity to refactor the hash index code in a couple
> places by moving duplicated code into separate functions, fixed some
> typos in the README file, etc.
>
> I've tested this a little bit (it survives 100,000 single-user pgbench
> transactions, and 10 concurrent clients doing 1000 transactions each),
> but I need to do more testing in the future.
>
> As far as I know, the unique hash index code is functionally complete,
> but don't add this to the patch queue (it is obviously for 7.5, anyway),
> since I'm about to get started on some related hash index work, for
> which I'll submit a mega-patch containing everything. I just posted this
> here so that anyone who's interested can take a look at it -- comments
> are welcome.
>
> Thanks to Tom Lane, who was very helpful when I asked him code
> questions, including suggesting the improved concurrency design I
> mentioned above.
>
> Cheers,
>
> Neil
>

[ Attachment, skipping... ]

>
> ---------------------------(end of broadcast)---------------------------
> TIP 9: the planner will ignore your desire to choose an index scan if your
>       joining column's datatypes do not match

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