Horton

Re: Making all nbtree entries unique by having heap TIDs participate in comparisons

Andrei Lepikhov <a.lepikhov@postgrespro.ru>

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From: Andrey Lepikhov <a.lepikhov@postgrespro.ru>
To: Peter Geoghegan <pg@bowt.ie>, Heikki Linnakangas <hlinnaka@iki.fi>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Alexander Korotkov <a.korotkov@postgrespro.ru>, Thomas Munro <thomas.munro@enterprisedb.com>, Claudio Freire <klaussfreire@gmail.com>, Anastasia Lubennikova <a.lubennikova@postgrespro.ru>
Date: 2018-11-04T03:52:35Z
Lists: pgsql-hackers 

On 03.11.2018 5:00, Peter Geoghegan wrote:
> The DESC heap TID sort order thing probably needs to go. I'll probably
> have to go fix the regression test failures that occur when ASC heap
> TID order is used. (Technically those failures are a pre-existing
> problem, a problem that I mask by using DESC order...which is weird.
> The problem is masked in the master branch by accidental behaviors
> around nbtree duplicates, which is something that deserves to die.
> DESC order is closer to the accidental current behavior.)

I applied your patches at top of master. After tests corrections 
(related to TID ordering in index relations DROP...CASCADE operation) 
'make check-world' passed successfully many times.
In the case of 'create view' regression test - 'drop cascades to 62 
other objects' problem - I verify an Álvaro Herrera hypothesis [1] and 
it is true. You can verify it by tracking the 
object_address_present_add_flags() routine return value.
Some doubts, however, may be regarding the 'triggers' test.
May you specify the test failures do you mean?

[1] 
https://www.postgresql.org/message-id/20180504022601.fflymidf7eoencb2%40alvherre.pgsql

-- 
Andrey Lepikhov
Postgres Professional
https://postgrespro.com
The Russian Postgres Company

Commits

  1. Add "split after new tuple" nbtree optimization.

  2. Add nbtree high key "continuescan" optimization.

  3. Allow amcheck to re-find tuples using new search.

  4. Consider secondary factors during nbtree splits.

  5. Make heap TID a tiebreaker nbtree index column.

  6. Refactor nbtree insertion scankeys.

  7. Redesign the partition dependency mechanism.

  8. Avoid unnecessary palloc overhead in _bt_first(). The temporary