Horton

Re: Hash Indexes

Robert Haas <robertmhaas@gmail.com>

View thread View on postgr.es
From: Robert Haas <robertmhaas@gmail.com>
To: Peter Geoghegan <pg@heroku.com>
Cc: Andres Freund <andres@anarazel.de>, Jesper Pedersen <jesper.pedersen@redhat.com>, Amit Kapila <amit.kapila16@gmail.com>, Jeff Janes <jeff.janes@gmail.com>, Mithun Cy <mithun.cy@enterprisedb.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2016-09-30T00:14:40Z
Lists: pgsql-hackers 
On Thu, Sep 29, 2016 at 8:07 PM, Peter Geoghegan <pg@heroku.com> wrote:
> On Wed, Sep 28, 2016 at 8:06 PM, Andres Freund <andres@anarazel.de> wrote:
>> On 2016-09-28 15:04:30 -0400, Robert Haas wrote:
>>> Andres already
>>> stated that he things working on btree-over-hash would be more
>>> beneficial than fixing hash, but at this point it seems like he's the
>>> only one who takes that position.
>>
>> Note that I did *NOT* take that position. I was saying that I think we
>> should evaluate whether that's not a better approach, doing some simple
>> performance comparisons.
>
> I, for one, agree with this position.

Well, I, for one, find it frustrating.  It seems pretty unhelpful to
bring this up only after the code has already been written.  The first
post on this thread was on May 10th.  The first version of the patch
was posted on June 16th.  This position was first articulated on
September 15th.

But, by all means, please feel free to do the performance comparison
and post the results.  I'd be curious to see them myself.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Remove _hash_wrtbuf() in favor of calling MarkBufferDirty().

  2. Fix race introduced by 6d46f4783efe457f74816a75173eb23ed8930020.

  3. Improve hash index bucket split behavior.

  4. Reduce pinning and buffer content locking for btree scans.