Revert "Skip WAL for new relfilenodes, under wal_level=minimal."

This reverts commit cb2fd7eac285b1b0a24eeb2b8ed4456b66c5a09f.  Per
numerous buildfarm members, it was incompatible with parallel query, and
a test case assumed LP64.  Back-patch to 9.5 (all supported versions).

Discussion: https://postgr.es/m/20200321224920.GB1763544@rfd.leadboat.com

1 files changed, 14 insertions, 8 deletions

diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 09ede4879f7..42c9e3bbaea 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -21,6 +21,7 @@
  *		heap_multi_insert - insert multiple tuples into a relation
  *		heap_delete		- delete a tuple from a relation
  *		heap_update		- replace a tuple in a relation with another tuple
+ *		heap_sync		- sync heap, for when no WAL has been written
  *
  * NOTES
  *	  This file contains the heap_ routines which implement
@@ -1935,7 +1936,7 @@ heap_insert(Relation relation, HeapTuple tup, CommandId cid,
 	MarkBufferDirty(buffer);
 
 	/* XLOG stuff */
-	if (RelationNeedsWAL(relation))
+	if (!(options & HEAP_INSERT_SKIP_WAL) && RelationNeedsWAL(relation))
 	{
 		xl_heap_insert xlrec;
 		xl_heap_header xlhdr;
@@ -2118,7 +2119,7 @@ heap_multi_insert(Relation relation, TupleTableSlot **slots, int ntuples,
 	/* currently not needed (thus unsupported) for heap_multi_insert() */
 	AssertArg(!(options & HEAP_INSERT_NO_LOGICAL));
 
-	needwal = RelationNeedsWAL(relation);
+	needwal = !(options & HEAP_INSERT_SKIP_WAL) && RelationNeedsWAL(relation);
 	saveFreeSpace = RelationGetTargetPageFreeSpace(relation,
 												   HEAP_DEFAULT_FILLFACTOR);
 
@@ -8920,13 +8921,18 @@ heap2_redo(XLogReaderState *record)
 }
 
 /*
- *	heap_sync		- for binary compatibility
+ *	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 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.
  *
- * A newer PostgreSQL version removes this function.  It exists here just in
- * case an extension calls it.  See "Skipping WAL for New RelFileNode" in
- * src/backend/access/transam/README for the system that superseded it,
- * allowing removal of most calls.  Cases like RelationCopyStorage() should
- * call smgrimmedsync() directly.
+ * Indexes are not touched.  (Currently, index operations associated with
+ * the commands that use this are WAL-logged and so do not need fsync.
+ * That behavior might change someday, but in any case it's likely that
+ * any fsync decisions required would be per-index and hence not appropriate
+ * to be done here.)
  */
 void
 heap_sync(Relation rel)