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Re: GIN improvements part2: fast scan - Mailing list pgsql-hackers

From Alexander Korotkov
Subject Re: GIN improvements part2: fast scan
Date
Msg-id CAPpHfdsMac=yQkkMi+HPN96EiCjvE1wBt9tveENq0tjti3r88w@mail.gmail.com
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In response to Re: GIN improvements part2: fast scan  (Heikki Linnakangas <hlinnakangas@vmware.com>)
Responses Re: GIN improvements part2: fast scan  (Tomas Vondra <tv@fuzzy.cz>)
Re: GIN improvements part2: fast scan  (Heikki Linnakangas <hlinnakangas@vmware.com>)
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On Fri, Feb 7, 2014 at 5:33 PM, Heikki Linnakangas <hlinnakangas@vmware.com> wrote:
On 02/06/2014 01:22 PM, Alexander Korotkov wrote:
Difference is very small. For me, it looks ready for commit.

Great, committed!

Now, to review the catalog changes...

I've rebased catalog changes with last master. Patch is attached. I've rerun my test suite with both last master ('committed') and attached patch ('ternary-consistent').

         method         |       sum
------------------------+------------------
 committed              | 143491.715000001
 fast-scan-11           | 126916.111999999
 fast-scan-light        |       137321.211
 fast-scan-light-heikki | 138168.028000001
 master                 |       446976.288
 ternary-consistent     |       125923.514

I explain regression in last master by change of MAX_MAYBE_ENTRIES from 8 to 4. However I'm not sure why ternary-consistent show so good results. Probably it's because some optimizations you did in committed version which wasn't visible because of change of MAX_MAYBE_ENTRIES.
I'm not sure about decision to reserve separate procedure number for ternary consistent. Probably, it would be better to add ginConfig method. It would be useful for post 9.4 improvements.

------
With best regards,
Alexander Korotkov.
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