Horton

Re: WIP: BRIN multi-range indexes

Tomas Vondra <tomas.vondra@enterprisedb.com>

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From: Tomas Vondra <tomas.vondra@enterprisedb.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: John Naylor <john.naylor@enterprisedb.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-03-03T01:17:20Z
Lists: pgsql-hackers 

On 3/3/21 1:17 AM, Alvaro Herrera wrote:
> On 2021-Mar-03, Tomas Vondra wrote:
> 
>> That's kinda my point - I agree the size of the patch is not the
>> primary concern, but it makes the minmax/inclusion code a bit more
>> complicated (because they now have to loop over the keys), with
>> very little benefit (there might be some speedup, but IMO it's
>> rather negligible).
> 
> Yeah, OK.
> 
>> Alternatively we could simply remove the code supporting the old
>> API with "consistent" functions without the additional parameter.
>> But the idea was to seamlessly support existing opclasses / not
>> breaking them unnecessarily (I know we don't guarantee that in
>> major upgrades, but as they may not benefit from this, why break
>> them?). It'd simplify the code in brin.c a little bit, but the
>> opclasses a bit more complex.
> 
> Well, I doubt any opclass-support functions exist outside of core. Or
> am I just outdated and we do know of some?
> 

I'm not aware of any. This was proposed by Nikita Glukhov:

https://www.postgresql.org/message-id/49cb668f-d6f9-3493-681d-7d40b715ef64%40postgrespro.ru

Alexander Korotkov seemed to agree with Nikita, but I don't recall any
references to actual existing opclasses.

Then again - the amount of code to support two signatures is fairly
small. If we decide to get rid of it, then fine - but the new complexity
in minmax/inclusion likely exceeds that.

Which is why I was thinking about still supporting both signatures, but
reverting the changes in brin_minmax and brin_inclusion.


regards

-- 
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. BRIN minmax-multi indexes

  2. BRIN bloom indexes

  3. Support the old signature of BRIN consistent function

  4. Remove unnecessary pg_amproc BRIN minmax entries

  5. Optimize allocations in bringetbitmap

  6. Move IS [NOT] NULL handling from BRIN support functions

  7. Pass all scan keys to BRIN consistent function at once

  8. Properly detoast data in brin_form_tuple