Re: POC: converting Lists into arrays

Andres Freund <andres@anarazel.de>

From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@lists.postgresql.org
Date: 2019-07-31T23:00:47Z
Lists: pgsql-hackers
Hi,

On 2019-07-31 15:57:56 -0700, Andres Freund wrote:
> I also wonder if a foreach version that includes the typical
> (Type *) var = (Type *) lfirst(lc);
> or
> (Type *) var = castNode(Type, lfirst(lc));
> or
> OpExpr	   *hclause = lfirst_node(OpExpr, lc);
> 
> would make it nicer to use lists.
> 
> foreach_node_in(Type, name, list) could mean something like
> 
> foreach(ListCell *name##_cell, list)
> {
>     Type* name = lfirst_node(Type, name##_cell);
> }

s/lfirst/linitial/ of course. Was looking at code that also used
lfirst...

Reminds me that one advantage of macros like the second one would also
be to reduce the use of the confusingly named linitial*(), helping newer
hackers.

Greetings,

Andres Freund



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.