Refactor reloption handling for index AMs in-core

This reworks the reloption parsing and build of a couple of index AMs by
creating new structures for each index AM's options.  This split was
already done for BRIN, GIN and GiST (which actually has a fillfactor
parameter), but not for hash, B-tree and SPGiST which relied on
StdRdOptions due to an overlap with the default option set.

This saves a couple of bytes for rd_options in each relcache entry with
indexes making use of relation options, and brings more consistency
between all index AMs.  While on it, add a couple of AssertMacro() calls
to make sure that utility macros to grab values of reloptions are used
with the expected index AM.

Author: Nikolay Shaplov
Reviewed-by: Amit Langote, Michael Paquier, Álvaro Herrera, Dent John
Discussion: https://postgr.es/m/4127670.gFlpRb6XCm@x200m

src/backend/access/common/reloptions.c

@@ -23,7 +23,7 @@
 #include "access/htup_details.h"
 #include "access/nbtree.h"
 #include "access/reloptions.h"
-#include "access/spgist.h"
+#include "access/spgist_private.h"
 #include "catalog/pg_type.h"
 #include "commands/defrem.h"
 #include "commands/tablespace.h"
@@ -1521,8 +1521,6 @@ default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
 		offsetof(StdRdOptions, user_catalog_table)},
 		{"parallel_workers", RELOPT_TYPE_INT,
 		offsetof(StdRdOptions, parallel_workers)},
-		{"vacuum_cleanup_index_scale_factor", RELOPT_TYPE_REAL,
-		offsetof(StdRdOptions, vacuum_cleanup_index_scale_factor)},
 		{"vacuum_index_cleanup", RELOPT_TYPE_BOOL,
 		offsetof(StdRdOptions, vacuum_index_cleanup)},
 		{"vacuum_truncate", RELOPT_TYPE_BOOL,

src/backend/access/hash/hashpage.c

@@ -358,7 +358,7 @@ _hash_init(Relation rel, double num_tuples, ForkNumber forkNum)
 	data_width = sizeof(uint32);
 	item_width = MAXALIGN(sizeof(IndexTupleData)) + MAXALIGN(data_width) +
 		sizeof(ItemIdData);		/* include the line pointer */
-	ffactor = RelationGetTargetPageUsage(rel, HASH_DEFAULT_FILLFACTOR) / item_width;
+	ffactor = HashGetTargetPageUsage(rel) / item_width;
 	/* keep to a sane range */
 	if (ffactor < 10)
 		ffactor = 10;

src/backend/access/hash/hashutil.c

@@ -289,7 +289,14 @@ _hash_checkpage(Relation rel, Buffer buf, int flags)
 bytea *
 hashoptions(Datum reloptions, bool validate)
 {
-	return default_reloptions(reloptions, validate, RELOPT_KIND_HASH);
+	static const relopt_parse_elt tab[] = {
+		{"fillfactor", RELOPT_TYPE_INT, offsetof(HashOptions, fillfactor)},
+	};
+
+	return (bytea *) build_reloptions(reloptions, validate,
+									  RELOPT_KIND_HASH,
+									  sizeof(HashOptions),
+									  tab, lengthof(tab));
 }
 
 /*

src/backend/access/nbtree/nbtree.c

@@ -816,7 +816,7 @@ _bt_vacuum_needs_cleanup(IndexVacuumInfo *info)
 	}
 	else
 	{
-		StdRdOptions *relopts;
+		BTOptions  *relopts;
 		float8		cleanup_scale_factor;
 		float8		prev_num_heap_tuples;
 
@@ -827,7 +827,7 @@ _bt_vacuum_needs_cleanup(IndexVacuumInfo *info)
 		 * tuples exceeds vacuum_cleanup_index_scale_factor fraction of
 		 * original tuples count.
 		 */
-		relopts = (StdRdOptions *) info->index->rd_options;
+		relopts = (BTOptions *) info->index->rd_options;
 		cleanup_scale_factor = (relopts &&
 								relopts->vacuum_cleanup_index_scale_factor >= 0)
 			? relopts->vacuum_cleanup_index_scale_factor

src/backend/access/nbtree/nbtsort.c

@@ -716,8 +716,8 @@ _bt_pagestate(BTWriteState *wstate, uint32 level)
 	if (level > 0)
 		state->btps_full = (BLCKSZ * (100 - BTREE_NONLEAF_FILLFACTOR) / 100);
 	else
-		state->btps_full = RelationGetTargetPageFreeSpace(wstate->index,
-														  BTREE_DEFAULT_FILLFACTOR);
+		state->btps_full = BTGetTargetPageFreeSpace(wstate->index);
+
 	/* no parent level, yet */
 	state->btps_next = NULL;
 

src/backend/access/nbtree/nbtsplitloc.c

@@ -167,7 +167,7 @@ _bt_findsplitloc(Relation rel,
 
 	/* Count up total space in data items before actually scanning 'em */
 	olddataitemstotal = rightspace - (int) PageGetExactFreeSpace(page);
-	leaffillfactor = RelationGetFillFactor(rel, BTREE_DEFAULT_FILLFACTOR);
+	leaffillfactor = BTGetFillFactor(rel);
 
 	/* Passed-in newitemsz is MAXALIGNED but does not include line pointer */
 	newitemsz += sizeof(ItemIdData);

src/backend/access/nbtree/nbtutils.c

@@ -2014,7 +2014,18 @@ BTreeShmemInit(void)
 bytea *
 btoptions(Datum reloptions, bool validate)
 {
-	return default_reloptions(reloptions, validate, RELOPT_KIND_BTREE);
+	static const relopt_parse_elt tab[] = {
+		{"fillfactor", RELOPT_TYPE_INT, offsetof(BTOptions, fillfactor)},
+		{"vacuum_cleanup_index_scale_factor", RELOPT_TYPE_REAL,
+		offsetof(BTOptions, vacuum_cleanup_index_scale_factor)}
+
+	};
+
+	return (bytea *) build_reloptions(reloptions, validate,
+									  RELOPT_KIND_BTREE,
+									  sizeof(BTOptions),
+									  tab, lengthof(tab));
+
 }
 
 /*

src/backend/access/spgist/spgutils.c

@@ -408,8 +408,7 @@ SpGistGetBuffer(Relation index, int flags, int needSpace, bool *isNew)
 	 * related to the ones already on it.  But fillfactor mustn't cause an
 	 * error for requests that would otherwise be legal.
 	 */
-	needSpace += RelationGetTargetPageFreeSpace(index,
-												SPGIST_DEFAULT_FILLFACTOR);
+	needSpace += SpGistGetTargetPageFreeSpace(index);
 	needSpace = Min(needSpace, SPGIST_PAGE_CAPACITY);
 
 	/* Get the cache entry for this flags setting */
@@ -586,7 +585,15 @@ SpGistInitMetapage(Page page)
 bytea *
 spgoptions(Datum reloptions, bool validate)
 {
-	return default_reloptions(reloptions, validate, RELOPT_KIND_SPGIST);
+	static const relopt_parse_elt tab[] = {
+		{"fillfactor", RELOPT_TYPE_INT, offsetof(SpGistOptions, fillfactor)},
+	};
+
+	return (bytea *) build_reloptions(reloptions, validate,
+									  RELOPT_KIND_SPGIST,
+									  sizeof(SpGistOptions),
+									  tab, lengthof(tab));
+
 }
 
 /*