Horton

Re: Removing unneeded self joins

Alexander Kuzmenkov <a.kuzmenkov@postgrespro.ru>

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From: Alexander Kuzmenkov <a.kuzmenkov@postgrespro.ru>
To: David Rowley <david.rowley@2ndquadrant.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-07-27T12:26:03Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Remove GUC_NOT_IN_SAMPLE from enable_self_join_elimination

  2. Put enable_self_join_elimination into postgresql.conf.sample

  3. Get rid of ojrelid local variable in remove_rel_from_query()

  4. Implement Self-Join Elimination

  5. Revert: Remove useless self-joins

  6. Replace lateral references to removed rels in subqueries

  7. Replace relids in lateral subquery parse tree during SJE

  8. Forbid SJE with result relation

  9. Fix misuse of RelOptInfo.unique_for_rels cache by SJE

  10. Replace the relid in some missing fields during SJE

  11. Revert 56-bit relfilenode change and follow-up commits.

  12. Stabilize timetz test across DST transitions.

  13. Speed up finding EquivalenceClasses for a given set of rels

  14. Fix mark-and-restore-skipping test case to not be a self-join.

Attachments

Here is a current version of the patch, still rather experimental. Since 
the previous version, I fixed some bugs and added the possibility to 
remove a relation even when it is mentioned in target lists. I have to 
rewrite all references to the removed relation in targetlists and the 
equivalence classes, so that they point to the remaining relation. I 
change RestrictInfos in place, and update attr_needed and reltarget of 
the remaining relation. I also update equivalence members, and delete 
equivalence classes that become single-member.

I'm posting it a single file now, because all meaningful changes are in 
analyzejoins.c anyway.

-- 
Alexander Kuzmenkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company