Horton

Re: POC: converting Lists into arrays

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

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: David Rowley <david.rowley@2ndquadrant.com>
Cc: Andres Freund <andres@anarazel.de>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2019-02-28T19:28:44Z
Lists: pgsql-hackers 
David Rowley <david.rowley@2ndquadrant.com> writes:
> On Thu, 28 Feb 2019 at 09:26, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> 0001 below does this.  I found a couple of places that could use
>> forfive(), as well.  I think this is a clear legibility and
>> error-proofing win, and we should just push it.

> I've looked over this and I agree that it's a good idea.  Reducing the
> number of lnext() usages seems like a good idea in order to reduce the
> footprint of the main patch.

I've pushed that; thanks for reviewing!

>> 0002 below does this.  I'm having a hard time deciding whether this
>> part is a good idea or just code churn.  It might be more readable
>> (especially to newbies) but I can't evaluate that very objectively.

> I'm less decided on this.

Yeah, I think I'm just going to drop that idea.  People didn't seem
very sold on list_cell_is_last() being a readability improvement,
and it certainly does nothing to reduce the footprint of the main
patch.

I now need to rebase the main patch over what I pushed; off to do
that next.

			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.