pg_visibility: Use visibilitymap_count instead of loop.

This commit updates pg_visibility_map_summary() to use the
visibilitymap_count() API, replacing its own counting mechanism. This
simplifies the function and improves performance by leveraging the
vectorized implementation introduced in commit 41c51f0c68.

Author: Matthias van de Meent <[email protected]>
Reviewed-by: wenhui qiu <[email protected]>
Reviewed-by: Masahiko Sawada <[email protected]>
Discussion: https://postgr.es/m/CAEze2WgPu-EYYuYQimy=AHQHGa7w8EvLVve5DM5eGMR6zh-7sw@mail.gmail.com

diff --git a/contrib/pg_visibility/pg_visibility.c b/contrib/pg_visibility/pg_visibility.c
index 7046c1b5f8e54a7b32c487702f6ea98820ad35ca..715f5cdd17c5773ed0dad88e11b286b039f65b0e 100644 (file)
--- a/contrib/pg_visibility/pg_visibility.c
+++ b/contrib/pg_visibility/pg_visibility.c
@@ -270,11 +270,8 @@ pg_visibility_map_summary(PG_FUNCTION_ARGS)
 {
    Oid         relid = PG_GETARG_OID(0);
    Relation    rel;
-   BlockNumber nblocks;
-   BlockNumber blkno;
-   Buffer      vmbuffer = InvalidBuffer;
-   int64       all_visible = 0;
-   int64       all_frozen = 0;
+   BlockNumber all_visible = 0;
+   BlockNumber all_frozen = 0;
    TupleDesc   tupdesc;
    Datum       values[2];
    bool        nulls[2] = {0};
@@ -284,33 +281,15 @@ pg_visibility_map_summary(PG_FUNCTION_ARGS)
    /* Only some relkinds have a visibility map */
    check_relation_relkind(rel);
 
-   nblocks = RelationGetNumberOfBlocks(rel);
-
-   for (blkno = 0; blkno < nblocks; ++blkno)
-   {
-       int32       mapbits;
-
-       /* Make sure we are interruptible. */
-       CHECK_FOR_INTERRUPTS();
-
-       /* Get map info. */
-       mapbits = (int32) visibilitymap_get_status(rel, blkno, &vmbuffer);
-       if ((mapbits & VISIBILITYMAP_ALL_VISIBLE) != 0)
-           ++all_visible;
-       if ((mapbits & VISIBILITYMAP_ALL_FROZEN) != 0)
-           ++all_frozen;
-   }
+   visibilitymap_count(rel, &all_visible, &all_frozen);
 
-   /* Clean up. */
-   if (vmbuffer != InvalidBuffer)
-       ReleaseBuffer(vmbuffer);
    relation_close(rel, AccessShareLock);
 
    if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
        elog(ERROR, "return type must be a row type");
 
-   values[0] = Int64GetDatum(all_visible);
-   values[1] = Int64GetDatum(all_frozen);
+   values[0] = Int64GetDatum((int64) all_visible);
+   values[1] = Int64GetDatum((int64) all_frozen);
 
    PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
 }