Re: sortsupport for text - Mailing list pgsql-hackers

From Robert Haas
Subject Re: sortsupport for text
Date
Msg-id CA+TgmoZ0GC5OoEaatcTiNYOuA2E1qfp22SiK1qXkzr+zDTuZvg@mail.gmail.com
Whole thread Raw
In response to Re: sortsupport for text  (Peter Geoghegan <peter@2ndquadrant.com>)
Responses Re: sortsupport for text  (Peter Geoghegan <peter@2ndquadrant.com>)
List pgsql-hackers
On Mon, Jul 23, 2012 at 11:34 AM, Peter Geoghegan <peter@2ndquadrant.com> wrote:
> On 23 July 2012 16:09, Robert Haas <robertmhaas@gmail.com> wrote:
>> However, what this really boils down to is that you and Peter don't
>> like this line of code:
>>
>> +               tss->buflen1 = TYPEALIGN(TEXTBUFLEN, len1);
>
> I can only speak for myself, though I agree with your summary here.
>
>> What would you like it to say instead?
>>
>> The obvious formulation is:
>>
>> while (len1 < tss->buflen1)
>>     tss->buflen *= 2;
>
> That's what I had in mind. +1.
>
>> Or perhaps the following, which will normally be more efficient,
>> though possibly not as efficient as what I've got there now:
>>
>> tss->buflen = 1 << ffs(len1);
>
> I'm sorry, I don't follow you here. What is ffs() ?

Sorry, fls, not ffs.  I always get those mixed up.

See src/port/fls.c

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


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