Horton

Re: POC: converting Lists into arrays

Bruce Momjian <bruce@momjian.us>

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From: Bruce Momjian <bruce@momjian.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, David Rowley <david.rowley@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2019-03-04T22:03:54Z
Lists: pgsql-hackers 
On Mon, Mar  4, 2019 at 12:44:41PM -0500, Robert Haas wrote:
> I think that's a separate but also promising thing to attack, and I
> agree that it'd take a lot of work to get there.  I don't think that
> the problem with either parse-tree-copying or list usage is that no
> performance benefits are to be had; I think it's that the amount of
> work required to get those benefits is pretty large.  If it were
> otherwise, somebody likely would have done it before now.

Stupid question, but do we use any kind of reference counter to know if
two subsystems look at a structure, and a copy is required?

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +

Commits

  1. Remove EState.es_range_table_array.

  2. Rationalize use of list_concat + list_copy combinations.

  3. Cosmetic improvements in setup of planner's per-RTE arrays.

  4. Make better use of the new List implementation in a couple of places

  5. Fix sepgsql test results for commit d97b714a2.

  6. Avoid using lcons and list_delete_first where it's easy to do so.

  7. Remove lappend_cell...() family of List functions.

  8. Clean up some ad-hoc code for sorting and de-duplicating Lists.

  9. Redesign the API for list sorting (list_qsort becomes list_sort).

  10. Remove dead code.

  11. Represent Lists as expansible arrays, not chains of cons-cells.

  12. Standardize some more loops that chase down parallel lists.

  13. Reimplement the linked list data structure used throughout the backend.