Horton

Re: WIP: Covering + unique indexes.

Teodor Sigaev <teodor@sigaev.ru>

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From: Teodor Sigaev <teodor@sigaev.ru>
To: Anastasia Lubennikova <a.lubennikova@postgrespro.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: 2016-04-08T12:06:43Z
Lists: pgsql-hackers 
> 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()
-- 
Teodor Sigaev                                   E-mail: teodor@sigaev.ru
                                                    WWW: http://www.sigaev.ru/

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