Re: Rethinking MemoryContext creation

On 12/10/2017 04:42 PM, Tom Lane wrote:
> Peter Geoghegan <pg@bowt.ie> writes:
>> On Sat, Dec 9, 2017 at 5:53 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> Overall I'm seeing about a 5% improvement in a "pgbench -S" scenario,
>>> although that number is a bit shaky since the run-to-run variation
>>> is a few percent anyway.
> 
>> Is that with "-M prepared", too?
> 
> No, I didn't use that.
> 

FWIW I've done some measurements, and while there is a improvement, it's
far from 5%.

pgbench -S -c 1 -T 60

   master   patched
   -----------------
    18244     18534
    18369     18587
    18310     18479
    18346     18515
    18344     18557

pgbench -S -M prepared -c 1 -T 60

   master   patched
   -----------------
    35191     35231
    35115     35555
    35164     35686
    35110     35724
    35053     35762

So that's about 1.3% and 1.2% improvement. It seems fairly consistent,
but it might easily be due to different in layout of the binaries.

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
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