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[PATCH 8/8] Consider selectivity in choose_bitmap_and
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* [PATCH 8/8] Consider selectivity in choose_bitmap_and
@ 2021-03-11 11:57  Tomas Vondra <[email protected]>
  0 siblings, 0 replies; 2+ messages in thread

From: Tomas Vondra @ 2021-03-11 11:57 UTC (permalink / raw)

---
 src/backend/optimizer/path/indxpath.c | 38 ++++++++++++++++-----------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index ff536e6b24..36b29c6c7b 100644
--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@@ -1437,6 +1437,7 @@ choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths)
 	foreach(l, paths)
 	{
 		Path	   *ipath = (Path *) lfirst(l);
+		bool		duplicate = false;
 
 		pathinfo = classify_index_clause_usage(ipath, &clauselist);
 
@@ -1451,22 +1452,29 @@ choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths)
 		{
 			if (!pathinfoarray[i]->unclassifiable &&
 				bms_equal(pathinfo->clauseids, pathinfoarray[i]->clauseids))
-				break;
-		}
-		if (i < npaths)
-		{
-			/* duplicate clauseids, keep the cheaper one */
-			Cost		ncost;
-			Cost		ocost;
-			Selectivity nselec;
-			Selectivity oselec;
-
-			cost_bitmap_tree_node(pathinfo->path, &ncost, &nselec);
-			cost_bitmap_tree_node(pathinfoarray[i]->path, &ocost, &oselec);
-			if (ncost < ocost)
-				pathinfoarray[i] = pathinfo;
+			{
+				/* duplicate clauseids, keep the cheaper one
+				 *
+				 * XXX maybe this should just use path_usage_comparator?
+				 */
+				Cost		ncost;
+				Cost		ocost;
+				Selectivity nselec;
+				Selectivity oselec;
+
+				cost_bitmap_tree_node(pathinfo->path, &ncost, &nselec);
+				cost_bitmap_tree_node(pathinfoarray[i]->path, &ocost, &oselec);
+
+				if ((ncost < ocost) && (nselec < oselec))
+				{
+					pathinfoarray[i] = pathinfo;
+					duplicate = true;
+					break;
+				}
+			}
 		}
-		else
+
+		if (!duplicate)
 		{
 			/* not duplicate clauseids, add to array */
 			pathinfoarray[npaths++] = pathinfo;
-- 
2.26.2


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^ permalink  raw  reply  [nested|flat] 2+ messages in thread

* Re: Release and unpin buffers after leaving CRIT section in GIN.
@ 2026-02-17 10:14  Kirill Reshke <[email protected]>
  0 siblings, 0 replies; 2+ messages in thread

From: Kirill Reshke @ 2026-02-17 10:14 UTC (permalink / raw)
  To: Michael Paquier <[email protected]>; +Cc: pgsql-hackers

On Tue, 17 Feb 2026 at 15:07, Michael Paquier <[email protected]> wrote:
>
> On Tue, Feb 17, 2026 at 02:58:24PM +0500, Kirill Reshke wrote:
> > Few places in GIN code does not follow that. v1 fixes it.
>
> Yep.  That sounds pretty much right.  Thanks for the report.
> --
> Michael

Looks like there are two more instances of this on HEAD: in gistbuild
and log_newpage_range. Is it?

```
reshke@yezzey-cbdb-bench:~/cpg$ git diff
src/backend/access/gist/gistbuild.c
src/backend/access/transam/xloginsert.c
diff --git a/src/backend/access/gist/gistbuild.c
b/src/backend/access/gist/gistbuild.c
index 7f57c787f4c..8e0c083ffa7 100644
--- a/src/backend/access/gist/gistbuild.c
+++ b/src/backend/access/gist/gistbuild.c
@@ -305,10 +305,10 @@ gistbuild(Relation heap, Relation index,
IndexInfo *indexInfo)
                MarkBufferDirty(buffer);
                PageSetLSN(page, GistBuildLSN);

-               UnlockReleaseBuffer(buffer);
-
                END_CRIT_SECTION();

+               UnlockReleaseBuffer(buffer);
+
                /* Scan the table, inserting all the tuples to the index. */
                reltuples = table_index_build_scan(heap, index,
indexInfo, true, true,

            gistBuildCallback,
diff --git a/src/backend/access/transam/xloginsert.c
b/src/backend/access/transam/xloginsert.c
index d3acaa636c3..a9a1678acc9 100644
--- a/src/backend/access/transam/xloginsert.c
+++ b/src/backend/access/transam/xloginsert.c
@@ -1355,11 +1355,12 @@ log_newpage_range(Relation rel, ForkNumber forknum,
                recptr = XLogInsert(RM_XLOG_ID, XLOG_FPI);

                for (i = 0; i < nbufs; i++)
-               {
                        PageSetLSN(BufferGetPage(bufpack[i]), recptr);
-                       UnlockReleaseBuffer(bufpack[i]);
-               }
+
                END_CRIT_SECTION();
+
+               for (i = 0; i < nbufs; i++)
+                       UnlockReleaseBuffer(bufpack[i]);
        }
 }

```

-- 
Best regards,
Kirill Reshke






^ permalink  raw  reply  [nested|flat] 2+ messages in thread


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2021-03-11 11:57 [PATCH 8/8] Consider selectivity in choose_bitmap_and Tomas Vondra <[email protected]>
2026-02-17 10:14 Re: Release and unpin buffers after leaving CRIT section in GIN. Kirill Reshke <[email protected]>

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