Re: sortsupport for text

Peter Geoghegan <peter@2ndquadrant.com>

From: Peter Geoghegan <peter@2ndquadrant.com>

To: Greg Stark <stark@mit.edu>

Cc: Tom Lane <tgl@sss.pgh.pa.us>, PG Hackers <pgsql-hackers@postgresql.org>, Robert Haas <robertmhaas@gmail.com>

Date: 2012-06-20T14:19:21Z

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 →

Adjust string comparison so that only bitwise-equal strings are considered
- 656beff59033 8.2.0 cited
Add operator strategy and comparison-value datatype fields to ScanKey.
- c1d62bfd00f4 8.0.0 cited

On 20 June 2012 15:10, Greg Stark <stark@mit.edu> wrote:
> On Sun, Jun 17, 2012 at 9:26 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> The trick for hashing such datatypes is to be able to guarantee that
>> "equal" values hash to the same hash code, which is typically possible
>> as long as you know the equality rules well enough.  We could possibly
>> do that for text with pure-strcoll equality if we knew all the details
>> of what strcoll would consider "equal", but we do not.
>
> It occurs to me that strxfrm would answer this question. If we made
> the hash function hash the result of strxfrm then we could make
> equality use strcoll and not fall back to strcmp.

What about per-column collations?

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