Horton

Re: WIP: Covering + unique indexes.

Anastasia Lubennikova <a.lubennikova@postgrespro.ru>

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From: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>
To: Teodor Sigaev <teodor@sigaev.ru>
Cc: Peter Geoghegan <pg@heroku.com>, David Steele <david@pgmasters.net>, Michael Paquier <michael.paquier@gmail.com>, PostgreSQL mailing lists <pgsql-hackers@postgresql.org>, David Rowley <david.rowley@2ndquadrant.com>
Date: 2016-04-08T15:05:04Z
Lists: pgsql-hackers

Attachments

08.04.2016 15:45, Anastasia Lubennikova:
> 08.04.2016 15:06, Teodor Sigaev:
>>> On Wed, Apr 6, 2016 at 1:50 PM, Peter Geoghegan <pg@heroku.com> wrote:
>>>> Personally, I like documenting assertions, and will sometimes write
>>>> assertions that the compiler could easily optimize away. Maybe going
>>>> *that* far is more a matter of personal style, but I think an
>>>> assertion about the new index tuple size being <= the old one is just
>>>> a good idea. It's not about a problem in your code at all.
>>>
>>> You should make index_truncate_tuple()/index_reform_tuple() promise to
>>> always do this in its comments/contract with caller as part of this,
>>> IMV.
>>>
>> Some notices:
>> - index_truncate_tuple(Relation idxrel, IndexTuple olditup, int 
>> indnatts,
>>                        int  indnkeyatts)
>>   Why we need indnatts/indnkeyatts? They are presented in idxrel struct
>>   already
>> - follow code where index_truncate_tuple() is called, it should never 
>> called in
>>   case where indnatts == indnkeyatts. So, indnkeyatts should be 
>> strictly less
>>   than indnatts, pls, change assertion. If they are equal the this 
>> function
>>   becomes complicated variant of CopyIndexTuple()
>
> Good point. These attributes seem to be there since previous versions 
> of the function.
> But now they are definitely unnecessary. Updated patch is attached

One more improvement - note about expressions into documentation.

-- 
Anastasia Lubennikova
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company

Commits

  1. Adjust INCLUDE index truncation comments and code.

  2. Add commentary explaining why MaxIndexTuplesPerPage calculation is safe.

  3. Indexes with INCLUDE columns and their support in B-tree

  4. Add amcheck verification of heap relations belonging to btree indexes.

  5. Doc: move info for btree opclass implementors into main documentation.

  6. Doc: mention that you can't PREPARE TRANSACTION after NOTIFY.

  7. Remove dedicated B-tree root-split record types.

  8. Restructure index access method API to hide most of it at the C level.

  9. Split _bt_insertonpg to two functions.

  10. Major overhaul of btree index code. Eliminate special BTP_CHAIN logic for