Re: B-Tree support function number 3 (strxfrm() optimization) - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: B-Tree support function number 3 (strxfrm() optimization)
Date
Msg-id 5416C6E8.2090401@vmware.com
Whole thread Raw
In response to Re: B-Tree support function number 3 (strxfrm() optimization)  (Peter Geoghegan <pg@heroku.com>)
List pgsql-hackers
On 09/14/2014 11:34 PM, Peter Geoghegan wrote:
> On Sun, Sep 14, 2014 at 7:37 AM, Heikki Linnakangas
> <hlinnakangas@vmware.com> wrote:
>> Both values vary in range 5.9 - 6.1 s, so it's fair to say that the useless
>> memcmp() is free with these parameters.
>>
>> Is this the worst case scenario?
>
> Other than pushing the differences much much later in the strings
> (which you surely thought of already), yes.

Please test the absolute worst case scenario you can think of. As I said 
earlier, if you can demonstrate that the slowdown of that is acceptable, 
we don't even need to discuss how likely or realistic the case is.

- Heikki




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