Horton

Re: sortsupport for text

Peter Geoghegan <peter@2ndquadrant.com>

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From: Peter Geoghegan <peter@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Kevin Grittner <Kevin.Grittner@wicourts.gov>, Robert Haas <robertmhaas@gmail.com>, Greg Stark <stark@mit.edu>, PG Hackers <pgsql-hackers@postgresql.org>
Date: 2012-06-21T02:17:14Z
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.

On 21 June 2012 01:22, Peter Geoghegan <peter@2ndquadrant.com> wrote:
> I've written a very small C++ program, which I've attached, that
> basically proves that this can still make a fairly large difference -
> I hope it's okay that that it's C++, but that allowed me to write the
> program quickly, with no dependencies for anyone who cares to try this
> out, other than a C++ compiler and the standard library.

So, it turns out that with a relatively expensive to sort collation
like hu_HU.UTF-8, the difference here is huge:

[peter@peterlaptop strxfrm_test]$ ./a.out
locale set: hu_HU.UTF-8
Time elapsed with strcoll: 11.122695 seconds
Time elapsed with strxfrm optimization: 2.328365 seconds
Time elapsed with strcoll: 11.404160 seconds
Time elapsed with strxfrm optimization: 2.355684 seconds
Time elapsed with strcoll: 11.411680 seconds
Time elapsed with strxfrm optimization: 2.342553 seconds
Time elapsed with strcoll: 11.415693 seconds
Time elapsed with strxfrm optimization: 2.343593 seconds
Time elapsed with strcoll: 11.428686 seconds
Time elapsed with strxfrm optimization: 2.345204 seconds
*****strcoll average: 11.356583 strxfrm average: 2.343080*****

-- 
Peter Geoghegan       http://www.2ndQuadrant.com/
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