Re: Minor performance improvement in transition to external sort - Mailing list pgsql-hackers

On 06/02/14 22:12, Jeremy Harris wrote:
>>  Did you try sorting already-sorted, reverse
>> sorted, or pipe-organ shaped data sets?

Summary (low numbers better):

Random ints:         83% compares, level on time.
Sorted ints:         level compares, 70% time.
Reverse-sorted ints: 10% compares, 15% time      (!)
Constant ints:       200% compares, 360% time    (ouch, and not O(n))
Pipe-organ ints:     80% compares, 107% time
Random text:         83% compares, 106% time

--
Cheers,
   Jeremy