Ignore BRIN indexes when checking for HOT udpates

When determining whether an index update may be skipped by using HOT, we
can ignore attributes indexed only by BRIN indexes. There are no index
pointers to individual tuples in BRIN, and the page range summary will
be updated anyway as it relies on visibility info.

This also removes rd_indexattr list, and replaces it with rd_attrsvalid
flag. The list was not used anywhere, and a simple flag is sufficient.

Patch by Josef Simanek, various fixes and improvements by me.

Author: Josef Simanek
Reviewed-by: Tomas Vondra, Alvaro Herrera
Discussion: https://postgr.es/m/CAFp7QwpMRGcDAQumN7onN9HjrJ3u4X3ZRXdGFT0K5G2JWvnbWg%40mail.gmail.com

1 files changed, 29 insertions, 21 deletions

diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 9fa9e671a11..e1ea079e9e3 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -2428,10 +2428,10 @@ RelationDestroyRelation(Relation relation, bool remember_tupdesc)
 	list_free_deep(relation->rd_fkeylist);
 	list_free(relation->rd_indexlist);
 	list_free(relation->rd_statlist);
-	bms_free(relation->rd_indexattr);
 	bms_free(relation->rd_keyattr);
 	bms_free(relation->rd_pkattr);
 	bms_free(relation->rd_idattr);
+	bms_free(relation->rd_hotblockingattr);
 	if (relation->rd_pubactions)
 		pfree(relation->rd_pubactions);
 	if (relation->rd_options)
@@ -5105,10 +5105,10 @@ RelationGetIndexPredicate(Relation relation)
 Bitmapset *
 RelationGetIndexAttrBitmap(Relation relation, IndexAttrBitmapKind attrKind)
 {
-	Bitmapset  *indexattrs;		/* indexed columns */
 	Bitmapset  *uindexattrs;	/* columns in unique indexes */
 	Bitmapset  *pkindexattrs;	/* columns in the primary index */
 	Bitmapset  *idindexattrs;	/* columns in the replica identity */
+	Bitmapset  *hotblockingattrs;   /* columns with HOT blocking indexes */
 	List	   *indexoidlist;
 	List	   *newindexoidlist;
 	Oid			relpkindex;
@@ -5117,18 +5117,18 @@ RelationGetIndexAttrBitmap(Relation relation, IndexAttrBitmapKind attrKind)
 	MemoryContext oldcxt;
 
 	/* Quick exit if we already computed the result. */
-	if (relation->rd_indexattr != NULL)
+	if (relation->rd_attrsvalid)
 	{
 		switch (attrKind)
 		{
-			case INDEX_ATTR_BITMAP_ALL:
-				return bms_copy(relation->rd_indexattr);
 			case INDEX_ATTR_BITMAP_KEY:
 				return bms_copy(relation->rd_keyattr);
 			case INDEX_ATTR_BITMAP_PRIMARY_KEY:
 				return bms_copy(relation->rd_pkattr);
 			case INDEX_ATTR_BITMAP_IDENTITY_KEY:
 				return bms_copy(relation->rd_idattr);
+			case INDEX_ATTR_BITMAP_HOT_BLOCKING:
+				return bms_copy(relation->rd_hotblockingattr);
 			default:
 				elog(ERROR, "unknown attrKind %u", attrKind);
 		}
@@ -5159,7 +5159,7 @@ restart:
 	relreplindex = relation->rd_replidindex;
 
 	/*
-	 * For each index, add referenced attributes to indexattrs.
+	 * For each index, add referenced attributes to appropriate bitmaps.
 	 *
 	 * Note: we consider all indexes returned by RelationGetIndexList, even if
 	 * they are not indisready or indisvalid.  This is important because an
@@ -5168,10 +5168,10 @@ restart:
 	 * CONCURRENTLY is far enough along that we should ignore the index, it
 	 * won't be returned at all by RelationGetIndexList.
 	 */
-	indexattrs = NULL;
 	uindexattrs = NULL;
 	pkindexattrs = NULL;
 	idindexattrs = NULL;
+	hotblockingattrs = NULL;
 	foreach(l, indexoidlist)
 	{
 		Oid			indexOid = lfirst_oid(l);
@@ -5236,8 +5236,9 @@ restart:
 			 */
 			if (attrnum != 0)
 			{
-				indexattrs = bms_add_member(indexattrs,
-											attrnum - FirstLowInvalidHeapAttributeNumber);
+				if (indexDesc->rd_indam->amhotblocking)
+					hotblockingattrs = bms_add_member(hotblockingattrs,
+												 attrnum - FirstLowInvalidHeapAttributeNumber);
 
 				if (isKey && i < indexDesc->rd_index->indnkeyatts)
 					uindexattrs = bms_add_member(uindexattrs,
@@ -5254,10 +5255,15 @@ restart:
 		}
 
 		/* Collect all attributes used in expressions, too */
-		pull_varattnos(indexExpressions, 1, &indexattrs);
+		if (indexDesc->rd_indam->amhotblocking)
+			pull_varattnos(indexExpressions, 1, &hotblockingattrs);
 
-		/* Collect all attributes in the index predicate, too */
-		pull_varattnos(indexPredicate, 1, &indexattrs);
+		/*
+		 * Collect all attributes in the index predicate, too. We have to ignore
+		 * amhotblocking flag, because the row might become indexable, in which
+		 * case we have to add it to the index.
+		 */
+		pull_varattnos(indexPredicate, 1, &hotblockingattrs);
 
 		index_close(indexDesc, AccessShareLock);
 	}
@@ -5285,25 +5291,25 @@ restart:
 		bms_free(uindexattrs);
 		bms_free(pkindexattrs);
 		bms_free(idindexattrs);
-		bms_free(indexattrs);
+		bms_free(hotblockingattrs);
 
 		goto restart;
 	}
 
 	/* Don't leak the old values of these bitmaps, if any */
-	bms_free(relation->rd_indexattr);
-	relation->rd_indexattr = NULL;
 	bms_free(relation->rd_keyattr);
 	relation->rd_keyattr = NULL;
 	bms_free(relation->rd_pkattr);
 	relation->rd_pkattr = NULL;
 	bms_free(relation->rd_idattr);
 	relation->rd_idattr = NULL;
+	bms_free(relation->rd_hotblockingattr);
+	relation->rd_hotblockingattr = NULL;
 
 	/*
 	 * Now save copies of the bitmaps in the relcache entry.  We intentionally
-	 * set rd_indexattr last, because that's the one that signals validity of
-	 * the values; if we run out of memory before making that copy, we won't
+	 * set rd_attrsvalid last, because that's what signals validity of the
+	 * values; if we run out of memory before making that copy, we won't
 	 * leave the relcache entry looking like the other ones are valid but
 	 * empty.
 	 */
@@ -5311,20 +5317,21 @@ restart:
 	relation->rd_keyattr = bms_copy(uindexattrs);
 	relation->rd_pkattr = bms_copy(pkindexattrs);
 	relation->rd_idattr = bms_copy(idindexattrs);
-	relation->rd_indexattr = bms_copy(indexattrs);
+	relation->rd_hotblockingattr = bms_copy(hotblockingattrs);
+	relation->rd_attrsvalid = true;
 	MemoryContextSwitchTo(oldcxt);
 
 	/* We return our original working copy for caller to play with */
 	switch (attrKind)
 	{
-		case INDEX_ATTR_BITMAP_ALL:
-			return indexattrs;
 		case INDEX_ATTR_BITMAP_KEY:
 			return uindexattrs;
 		case INDEX_ATTR_BITMAP_PRIMARY_KEY:
 			return pkindexattrs;
 		case INDEX_ATTR_BITMAP_IDENTITY_KEY:
 			return idindexattrs;
+		case INDEX_ATTR_BITMAP_HOT_BLOCKING:
+			return hotblockingattrs;
 		default:
 			elog(ERROR, "unknown attrKind %u", attrKind);
 			return NULL;
@@ -6180,10 +6187,11 @@ load_relcache_init_file(bool shared)
 		rel->rd_indexlist = NIL;
 		rel->rd_pkindex = InvalidOid;
 		rel->rd_replidindex = InvalidOid;
-		rel->rd_indexattr = NULL;
+		rel->rd_attrsvalid = false;
 		rel->rd_keyattr = NULL;
 		rel->rd_pkattr = NULL;
 		rel->rd_idattr = NULL;
+		rel->rd_hotblockingattr = NULL;
 		rel->rd_pubactions = NULL;
 		rel->rd_statvalid = false;
 		rel->rd_statlist = NIL;