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Remove fls(), use pg_leftmost_one_pos32() instead.

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Commit 4f658dc8 provided the traditional BSD fls() function in
src/port/fls.c so it could be used in several places.  Later we added a
bunch of similar facilities in pg_bitutils.h, based on compiler
builtins that map to hardware instructions.  It's a bit confusing to
have both 1-based and 0-based variants of this operation in use in
different parts of the tree, and neither is blessed by a standard.
Let's drop fls.c and the configure probe, and reuse the newer code.

Reviewed-by: David Rowley <dgrowleyml@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CA%2BhUKG%2B7dSX1XF8yFGmYk-%3D48dbjH2kmzZj16XvhbrWP-9BzRg%40mail.gmail.com
This commit is contained in:
Thomas Munro
2022-07-22 09:41:12 +12:00
parent 3225399021
commit 4f1f5a7f85
11 changed files with 19 additions and 92 deletions
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5
src/backend/optimizer/path/allpaths.c
View File

@@ -47,6 +47,7 @@
#include "parser/parsetree.h"
#include "partitioning/partbounds.h"
#include "partitioning/partprune.h"
#include "port/pg_bitutils.h"
#include "rewrite/rewriteManip.h"
#include "utils/lsyscache.h"
@@ -1491,7 +1492,7 @@ add_paths_to_append_rel(PlannerInfo *root, RelOptInfo *rel,
if (enable_parallel_append)
{
parallel_workers = Max(parallel_workers,
fls(list_length(live_childrels)));
pg_leftmost_one_pos32(list_length(live_childrels)) + 1);
parallel_workers = Min(parallel_workers,
max_parallel_workers_per_gather);
}
@@ -1542,7 +1543,7 @@ add_paths_to_append_rel(PlannerInfo *root, RelOptInfo *rel,
* the planned number of parallel workers.
*/
parallel_workers = Max(parallel_workers,
fls(list_length(live_childrels)));
pg_leftmost_one_pos32(list_length(live_childrels)) + 1);
parallel_workers = Min(parallel_workers,
max_parallel_workers_per_gather);
Assert(parallel_workers > 0);

2
src/backend/optimizer/prep/prepunion.c
View File

@@ -675,7 +675,7 @@ generate_union_paths(SetOperationStmt *op, PlannerInfo *root,
if (enable_parallel_append)
{
parallel_workers = Max(parallel_workers,
fls(list_length(partial_pathlist)));
pg_leftmost_one_pos32(list_length(partial_pathlist)) + 1);
parallel_workers = Min(parallel_workers,
max_parallel_workers_per_gather);
}