Generalize concept of temporary relations to "relation persistence".

This commit replaces pg_class.relistemp with pg_class.relpersistence;
and also modifies the RangeVar node type to carry relpersistence rather
than istemp.  It also removes removes rd_istemp from RelationData and
instead performs the correct computation based on relpersistence.

For clarity, we add three new macros: RelationNeedsWAL(),
RelationUsesLocalBuffers(), and RelationUsesTempNamespace(), so that we
can clarify the purpose of each check that previous depended on
rd_istemp.

This is intended as infrastructure for the upcoming unlogged tables
patch, as well as for future possible work on global temporary tables.

src/backend/access/gin/ginbtree.c

@@ -304,7 +304,7 @@ ginInsertValue(GinBtree btree, GinBtreeStack *stack, GinStatsData *buildStats)
 
 			MarkBufferDirty(stack->buffer);
 
-			if (!btree->index->rd_istemp)
+			if (RelationNeedsWAL(btree->index))
 			{
 				XLogRecPtr	recptr;
 
@@ -373,7 +373,7 @@ ginInsertValue(GinBtree btree, GinBtreeStack *stack, GinStatsData *buildStats)
 				MarkBufferDirty(lbuffer);
 				MarkBufferDirty(stack->buffer);
 
-				if (!btree->index->rd_istemp)
+				if (RelationNeedsWAL(btree->index))
 				{
 					XLogRecPtr	recptr;
 
@@ -422,7 +422,7 @@ ginInsertValue(GinBtree btree, GinBtreeStack *stack, GinStatsData *buildStats)
 				MarkBufferDirty(rbuffer);
 				MarkBufferDirty(stack->buffer);
 
-				if (!btree->index->rd_istemp)
+				if (RelationNeedsWAL(btree->index))
 				{
 					XLogRecPtr	recptr;
 

src/backend/access/gin/ginfast.c

@@ -103,7 +103,7 @@ writeListPage(Relation index, Buffer buffer,
 
 	MarkBufferDirty(buffer);
 
-	if (!index->rd_istemp)
+	if (RelationNeedsWAL(index))
 	{
 		XLogRecData rdata[2];
 		ginxlogInsertListPage data;
@@ -384,7 +384,7 @@ ginHeapTupleFastInsert(Relation index, GinState *ginstate,
 	 */
 	MarkBufferDirty(metabuffer);
 
-	if (!index->rd_istemp)
+	if (RelationNeedsWAL(index))
 	{
 		XLogRecPtr	recptr;
 
@@ -564,7 +564,7 @@ shiftList(Relation index, Buffer metabuffer, BlockNumber newHead,
 			MarkBufferDirty(buffers[i]);
 		}
 
-		if (!index->rd_istemp)
+		if (RelationNeedsWAL(index))
 		{
 			XLogRecPtr	recptr;
 

src/backend/access/gin/gininsert.c

@@ -55,7 +55,7 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems)
 
 	MarkBufferDirty(buffer);
 
-	if (!index->rd_istemp)
+	if (RelationNeedsWAL(index))
 	{
 		XLogRecPtr	recptr;
 		XLogRecData rdata[2];
@@ -325,7 +325,7 @@ ginbuild(PG_FUNCTION_ARGS)
 	GinInitBuffer(RootBuffer, GIN_LEAF);
 	MarkBufferDirty(RootBuffer);
 
-	if (!index->rd_istemp)
+	if (RelationNeedsWAL(index))
 	{
 		XLogRecPtr	recptr;
 		XLogRecData rdata;

src/backend/access/gin/ginutil.c

@@ -410,7 +410,7 @@ ginUpdateStats(Relation index, const GinStatsData *stats)
 
 	MarkBufferDirty(metabuffer);
 
-	if (!index->rd_istemp)
+	if (RelationNeedsWAL(index))
 	{
 		XLogRecPtr			recptr;
 		ginxlogUpdateMeta	data;

src/backend/access/gin/ginvacuum.c

@@ -93,7 +93,7 @@ xlogVacuumPage(Relation index, Buffer buffer)
 
 	Assert(GinPageIsLeaf(page));
 
-	if (index->rd_istemp)
+	if (!RelationNeedsWAL(index))
 		return;
 
 	data.node = index->rd_node;
@@ -308,7 +308,7 @@ ginDeletePage(GinVacuumState *gvs, BlockNumber deleteBlkno, BlockNumber leftBlkn
 		MarkBufferDirty(lBuffer);
 	MarkBufferDirty(dBuffer);
 
-	if (!gvs->index->rd_istemp)
+	if (RelationNeedsWAL(gvs->index))
 	{
 		XLogRecPtr	recptr;
 		XLogRecData rdata[4];

src/backend/access/gist/gist.c

@@ -115,7 +115,7 @@ gistbuild(PG_FUNCTION_ARGS)
 
 	MarkBufferDirty(buffer);
 
-	if (!index->rd_istemp)
+	if (RelationNeedsWAL(index))
 	{
 		XLogRecPtr	recptr;
 		XLogRecData rdata;
@@ -401,7 +401,7 @@ gistplacetopage(GISTInsertState *state, GISTSTATE *giststate)
 			dist->page = BufferGetPage(dist->buffer);
 		}
 
-		if (!state->r->rd_istemp)
+		if (RelationNeedsWAL(state->r))
 		{
 			XLogRecPtr	recptr;
 			XLogRecData *rdata;
@@ -465,7 +465,7 @@ gistplacetopage(GISTInsertState *state, GISTSTATE *giststate)
 
 		MarkBufferDirty(state->stack->buffer);
 
-		if (!state->r->rd_istemp)
+		if (RelationNeedsWAL(state->r))
 		{
 			OffsetNumber noffs = 0,
 						offs[1];
@@ -550,7 +550,7 @@ gistfindleaf(GISTInsertState *state, GISTSTATE *giststate)
 		opaque = GistPageGetOpaque(state->stack->page);
 
 		state->stack->lsn = PageGetLSN(state->stack->page);
-		Assert(state->r->rd_istemp || !XLogRecPtrIsInvalid(state->stack->lsn));
+		Assert(!RelationNeedsWAL(state->r) || !XLogRecPtrIsInvalid(state->stack->lsn));
 
 		if (state->stack->blkno != GIST_ROOT_BLKNO &&
 			XLByteLT(state->stack->parent->lsn, opaque->nsn))
@@ -911,7 +911,7 @@ gistmakedeal(GISTInsertState *state, GISTSTATE *giststate)
 	}
 
 	/* say to xlog that insert is completed */
-	if (state->needInsertComplete && !state->r->rd_istemp)
+	if (state->needInsertComplete && RelationNeedsWAL(state->r))
 		gistxlogInsertCompletion(state->r->rd_node, &(state->key), 1);
 }
 
@@ -1011,7 +1011,7 @@ gistnewroot(Relation r, Buffer buffer, IndexTuple *itup, int len, ItemPointer ke
 
 	MarkBufferDirty(buffer);
 
-	if (!r->rd_istemp)
+	if (RelationNeedsWAL(r))
 	{
 		XLogRecPtr	recptr;
 		XLogRecData *rdata;

src/backend/access/gist/gistvacuum.c

@@ -248,7 +248,7 @@ gistbulkdelete(PG_FUNCTION_ARGS)
 					PageIndexTupleDelete(page, todelete[i]);
 				GistMarkTuplesDeleted(page);
 
-				if (!rel->rd_istemp)
+				if (RelationNeedsWAL(rel))
 				{
 					XLogRecData *rdata;
 					XLogRecPtr	recptr;

src/backend/access/heap/heapam.c

@@ -124,7 +124,7 @@ initscan(HeapScanDesc scan, ScanKey key, bool is_rescan)
 	 *
 	 * During a rescan, don't make a new strategy object if we don't have to.
 	 */
-	if (!scan->rs_rd->rd_istemp &&
+	if (!RelationUsesLocalBuffers(scan->rs_rd) &&
 		scan->rs_nblocks > NBuffers / 4)
 	{
 		allow_strat = scan->rs_allow_strat;
@@ -905,7 +905,7 @@ relation_open(Oid relationId, LOCKMODE lockmode)
 		elog(ERROR, "could not open relation with OID %u", relationId);
 
 	/* Make note that we've accessed a temporary relation */
-	if (r->rd_istemp)
+	if (RelationUsesLocalBuffers(r))
 		MyXactAccessedTempRel = true;
 
 	pgstat_initstats(r);
@@ -951,7 +951,7 @@ try_relation_open(Oid relationId, LOCKMODE lockmode)
 		elog(ERROR, "could not open relation with OID %u", relationId);
 
 	/* Make note that we've accessed a temporary relation */
-	if (r->rd_istemp)
+	if (RelationUsesLocalBuffers(r))
 		MyXactAccessedTempRel = true;
 
 	pgstat_initstats(r);
@@ -1917,7 +1917,7 @@ heap_insert(Relation relation, HeapTuple tup, CommandId cid,
 	MarkBufferDirty(buffer);
 
 	/* XLOG stuff */
-	if (!(options & HEAP_INSERT_SKIP_WAL) && !relation->rd_istemp)
+	if (!(options & HEAP_INSERT_SKIP_WAL) && RelationNeedsWAL(relation))
 	{
 		xl_heap_insert xlrec;
 		xl_heap_header xlhdr;
@@ -2227,7 +2227,7 @@ l1:
 	MarkBufferDirty(buffer);
 
 	/* XLOG stuff */
-	if (!relation->rd_istemp)
+	if (RelationNeedsWAL(relation))
 	{
 		xl_heap_delete xlrec;
 		XLogRecPtr	recptr;
@@ -2780,7 +2780,7 @@ l2:
 	MarkBufferDirty(buffer);
 
 	/* XLOG stuff */
-	if (!relation->rd_istemp)
+	if (RelationNeedsWAL(relation))
 	{
 		XLogRecPtr	recptr = log_heap_update(relation, buffer, oldtup.t_self,
 											 newbuf, heaptup,
@@ -3403,7 +3403,7 @@ l3:
 	 * (Also, in a PITR log-shipping or 2PC environment, we have to have XLOG
 	 * entries for everything anyway.)
 	 */
-	if (!relation->rd_istemp)
+	if (RelationNeedsWAL(relation))
 	{
 		xl_heap_lock xlrec;
 		XLogRecPtr	recptr;
@@ -3505,7 +3505,7 @@ heap_inplace_update(Relation relation, HeapTuple tuple)
 	MarkBufferDirty(buffer);
 
 	/* XLOG stuff */
-	if (!relation->rd_istemp)
+	if (RelationNeedsWAL(relation))
 	{
 		xl_heap_inplace xlrec;
 		XLogRecPtr	recptr;
@@ -3867,8 +3867,8 @@ log_heap_clean(Relation reln, Buffer buffer,
 	XLogRecPtr	recptr;
 	XLogRecData rdata[4];
 
-	/* Caller should not call me on a temp relation */
-	Assert(!reln->rd_istemp);
+	/* Caller should not call me on a non-WAL-logged relation */
+	Assert(RelationNeedsWAL(reln));
 
 	xlrec.node = reln->rd_node;
 	xlrec.block = BufferGetBlockNumber(buffer);
@@ -3950,8 +3950,8 @@ log_heap_freeze(Relation reln, Buffer buffer,
 	XLogRecPtr	recptr;
 	XLogRecData rdata[2];
 
-	/* Caller should not call me on a temp relation */
-	Assert(!reln->rd_istemp);
+	/* Caller should not call me on a non-WAL-logged relation */
+	Assert(RelationNeedsWAL(reln));
 	/* nor when there are no tuples to freeze */
 	Assert(offcnt > 0);
 
@@ -3996,8 +3996,8 @@ log_heap_update(Relation reln, Buffer oldbuf, ItemPointerData from,
 	XLogRecData rdata[4];
 	Page		page = BufferGetPage(newbuf);
 
-	/* Caller should not call me on a temp relation */
-	Assert(!reln->rd_istemp);
+	/* Caller should not call me on a non-WAL-logged relation */
+	Assert(RelationNeedsWAL(reln));
 
 	if (HeapTupleIsHeapOnly(newtup))
 		info = XLOG_HEAP_HOT_UPDATE;
@@ -4997,7 +4997,7 @@ heap2_desc(StringInfo buf, uint8 xl_info, char *rec)
  *	heap_sync		- sync a heap, for use when no WAL has been written
  *
  * This forces the heap contents (including TOAST heap if any) down to disk.
- * If we skipped using WAL, and it's not a temp relation, we must force the
+ * If we skipped using WAL, and WAL is otherwise needed, we must force the
  * relation down to disk before it's safe to commit the transaction.  This
  * requires writing out any dirty buffers and then doing a forced fsync.
  *
@@ -5010,8 +5010,8 @@ heap2_desc(StringInfo buf, uint8 xl_info, char *rec)
 void
 heap_sync(Relation rel)
 {
-	/* temp tables never need fsync */
-	if (rel->rd_istemp)
+	/* non-WAL-logged tables never need fsync */
+	if (!RelationNeedsWAL(rel))
 		return;
 
 	/* main heap */

src/backend/access/heap/pruneheap.c

@@ -233,7 +233,7 @@ heap_page_prune(Relation relation, Buffer buffer, TransactionId OldestXmin,
 		/*
 		 * Emit a WAL HEAP_CLEAN record showing what we did
 		 */
-		if (!relation->rd_istemp)
+		if (RelationNeedsWAL(relation))
 		{
 			XLogRecPtr	recptr;
 

src/backend/access/heap/rewriteheap.c

@@ -277,8 +277,8 @@ end_heap_rewrite(RewriteState state)
 	}
 
 	/*
-	 * If the rel isn't temp, must fsync before commit.  We use heap_sync to
-	 * ensure that the toast table gets fsync'd too.
+	 * If the rel is WAL-logged, must fsync before commit.  We use heap_sync
+	 * to ensure that the toast table gets fsync'd too.
 	 *
 	 * It's obvious that we must do this when not WAL-logging. It's less
 	 * obvious that we have to do it even if we did WAL-log the pages. The
@@ -287,7 +287,7 @@ end_heap_rewrite(RewriteState state)
 	 * occurring during the rewriteheap operation won't have fsync'd data we
 	 * wrote before the checkpoint.
 	 */
-	if (!state->rs_new_rel->rd_istemp)
+	if (RelationNeedsWAL(state->rs_new_rel))
 		heap_sync(state->rs_new_rel);
 
 	/* Deleting the context frees everything */

src/backend/access/nbtree/nbtinsert.c

@@ -766,7 +766,7 @@ _bt_insertonpg(Relation rel,
 		}
 
 		/* XLOG stuff */
-		if (!rel->rd_istemp)
+		if (RelationNeedsWAL(rel))
 		{
 			xl_btree_insert xlrec;
 			BlockNumber xldownlink;
@@ -1165,7 +1165,7 @@ _bt_split(Relation rel, Buffer buf, OffsetNumber firstright,
 	}
 
 	/* XLOG stuff */
-	if (!rel->rd_istemp)
+	if (RelationNeedsWAL(rel))
 	{
 		xl_btree_split xlrec;
 		uint8		xlinfo;
@@ -1914,7 +1914,7 @@ _bt_newroot(Relation rel, Buffer lbuf, Buffer rbuf)
 	MarkBufferDirty(metabuf);
 
 	/* XLOG stuff */
-	if (!rel->rd_istemp)
+	if (RelationNeedsWAL(rel))
 	{
 		xl_btree_newroot xlrec;
 		XLogRecPtr	recptr;

src/backend/access/nbtree/nbtpage.c

@@ -224,7 +224,7 @@ _bt_getroot(Relation rel, int access)
 		MarkBufferDirty(metabuf);
 
 		/* XLOG stuff */
-		if (!rel->rd_istemp)
+		if (RelationNeedsWAL(rel))
 		{
 			xl_btree_newroot xlrec;
 			XLogRecPtr	recptr;
@@ -452,7 +452,7 @@ _bt_checkpage(Relation rel, Buffer buf)
 static void
 _bt_log_reuse_page(Relation rel, BlockNumber blkno, TransactionId latestRemovedXid)
 {
-	if (rel->rd_istemp)
+	if (!RelationNeedsWAL(rel))
 		return;
 
 	/* No ereport(ERROR) until changes are logged */
@@ -751,7 +751,7 @@ _bt_delitems_vacuum(Relation rel, Buffer buf,
 	MarkBufferDirty(buf);
 
 	/* XLOG stuff */
-	if (!rel->rd_istemp)
+	if (RelationNeedsWAL(rel))
 	{
 		XLogRecPtr	recptr;
 		XLogRecData rdata[2];
@@ -829,7 +829,7 @@ _bt_delitems_delete(Relation rel, Buffer buf,
 	MarkBufferDirty(buf);
 
 	/* XLOG stuff */
-	if (!rel->rd_istemp)
+	if (RelationNeedsWAL(rel))
 	{
 		XLogRecPtr	recptr;
 		XLogRecData rdata[3];
@@ -1365,7 +1365,7 @@ _bt_pagedel(Relation rel, Buffer buf, BTStack stack)
 		MarkBufferDirty(lbuf);
 
 	/* XLOG stuff */
-	if (!rel->rd_istemp)
+	if (RelationNeedsWAL(rel))
 	{
 		xl_btree_delete_page xlrec;
 		xl_btree_metadata xlmeta;

src/backend/access/nbtree/nbtsort.c

@@ -211,9 +211,9 @@ _bt_leafbuild(BTSpool *btspool, BTSpool *btspool2)
 
 	/*
 	 * We need to log index creation in WAL iff WAL archiving/streaming is
-	 * enabled AND it's not a temp index.
+	 * enabled UNLESS the index isn't WAL-logged anyway.
 	 */
-	wstate.btws_use_wal = XLogIsNeeded() && !wstate.index->rd_istemp;
+	wstate.btws_use_wal = XLogIsNeeded() && RelationNeedsWAL(wstate.index);
 
 	/* reserve the metapage */
 	wstate.btws_pages_alloced = BTREE_METAPAGE + 1;
@@ -797,9 +797,9 @@ _bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
 	_bt_uppershutdown(wstate, state);
 
 	/*
-	 * If the index isn't temp, we must fsync it down to disk before it's safe
-	 * to commit the transaction.  (For a temp index we don't care since the
-	 * index will be uninteresting after a crash anyway.)
+	 * If the index is WAL-logged, we must fsync it down to disk before it's
+	 * safe to commit the transaction.  (For a non-WAL-logged index we don't
+	 * care since the index will be uninteresting after a crash anyway.)
 	 *
 	 * It's obvious that we must do this when not WAL-logging the build. It's
 	 * less obvious that we have to do it even if we did WAL-log the index
@@ -811,7 +811,7 @@ _bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
 	 * fsync those pages here, they might still not be on disk when the crash
 	 * occurs.
 	 */
-	if (!wstate->index->rd_istemp)
+	if (RelationNeedsWAL(wstate->index))
 	{
 		RelationOpenSmgr(wstate->index);
 		smgrimmedsync(wstate->index->rd_smgr, MAIN_FORKNUM);