On Mon, Jul 23, 2012 at 12:07 PM, Peter Geoghegan <peter@2ndquadrant.com> wrote:
> On 23 July 2012 16:36, Robert Haas <robertmhaas@gmail.com> wrote:
>> On Mon, Jul 23, 2012 at 11:34 AM, Peter Geoghegan <peter@2ndquadrant.com> wrote:
>>>> 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
>
> Oh, okay. Since, I infer, we're starting from a buffer-size that's a
> power-of-two anyway, is there really any advantage in doing this
> rather than just doubling the buffer size each time?
Well, if you're using a builtin fls rather than our src/port
implementation, it's probably a single machine language instruction
instead of a loop.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
