Horton

Re: POC: converting Lists into arrays

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: David Rowley <david.rowley@2ndquadrant.com>
Cc: Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2019-03-05T00:36:12Z
Lists: pgsql-hackers 
David Rowley <david.rowley@2ndquadrant.com> writes:
> On Tue, 5 Mar 2019 at 12:54, Andres Freund <andres@anarazel.de> wrote:
>> Yes, I think you have a point that progress here would be good and that
>> it's worth some pain. But the names will make even less sense if we just
>> shunt in an array based approach under the already obscure list
>> API.

> If we feel strongly about fixing that then probably it would be as
> simple as renaming the functions and adding some macros with the old
> names and insisting that all new or changed code use the functions and
> not the macro wrappers.

Meh ... Neil Conway already did a round of that back in 2004 or whenever,
and I'm not especially excited about another round.  I'm not really
following Andres' aversion to the list API --- it's not any more obscure
than a whole lot of things in Postgres.  (Admittedly, as somebody who
dabbled in Lisp decades ago, I might be more used to it than some folks.)

			regards, tom lane

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.