Horton

Re: sortsupport for text

Kevin Grittner <kevin.grittner@wicourts.gov>

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From: "Kevin Grittner" <Kevin.Grittner@wicourts.gov>
To: "Robert Haas" <robertmhaas@gmail.com>, "Noah Misch" <noah@leadboat.com>
Cc: <pgsql-hackers@postgresql.org>
Date: 2012-03-08T16:29:56Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Adjust string comparison so that only bitwise-equal strings are considered

  2. Add operator strategy and comparison-value datatype fields to ScanKey.

Noah Misch <noah@leadboat.com> wrote:
> On Fri, Mar 02, 2012 at 03:45:38PM -0500, Robert Haas wrote:
 
>> SELECT SUM(1) FROM (SELECT * FROM randomtext ORDER BY t) x;
 
>> [13% faster with patch for C collation; 7% faster for UTF8]
 
>> I had hoped for more like a 15-20% gain from this approach, but
>> it didn't happen, I suppose because some of the instructions
>> saved just resulted in more processor stalls.  All the same, I'm
>> inclined to think it's still worth doing.
> 
> This is a border case, but I suggest that a 13% speedup on a 
> narrowly-tailored benchmark, degrading to 7% in common
> configurations, is too meager to justify adopting this patch.
 
We use the C collation and have character strings in most indexes
and ORDER BY clauses.  Unless there are significant contra-
indications, I'm in favor of adopting this patch.
 
-Kevin