Remove ReorderBufferTupleBuf structure.

Since commit a4ccc1cef, the 'node' and 'alloc_tuple_size' fields of
the ReorderBufferTupleBuf structure are no longer used. This leaves
only the 'tuple' field in the structure. Since keeping a single-field
structure makes little sense, the ReorderBufferTupleBuf is removed
entirely. The code is refactored accordingly.

No back-patching since these are ABI changes in an exposed structure
and functions, and there would be some risk of breaking extensions.

Author: Aleksander Alekseev
Reviewed-by: Amit Kapila, Masahiko Sawada, Reid Thompson
Discussion: https://postgr.es/m/CAD21AoCvnuxiXXfRecp7g9+CeC35POQfhuQeJFr7_9u_Q5jc_Q@mail.gmail.com

6 files changed, 68 insertions, 91 deletions

diff --git a/contrib/test_decoding/test_decoding.c b/contrib/test_decoding/test_decoding.c
index 4f4f51a89c1..7c50d139698 100644
--- a/contrib/test_decoding/test_decoding.c
+++ b/contrib/test_decoding/test_decoding.c
@@ -640,7 +640,7 @@ pg_decode_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 				appendStringInfoString(ctx->out, " (no-tuple-data)");
 			else
 				tuple_to_stringinfo(ctx->out, tupdesc,
-									&change->data.tp.newtuple->tuple,
+									change->data.tp.newtuple,
 									false);
 			break;
 		case REORDER_BUFFER_CHANGE_UPDATE:
@@ -649,7 +649,7 @@ pg_decode_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 			{
 				appendStringInfoString(ctx->out, " old-key:");
 				tuple_to_stringinfo(ctx->out, tupdesc,
-									&change->data.tp.oldtuple->tuple,
+									change->data.tp.oldtuple,
 									true);
 				appendStringInfoString(ctx->out, " new-tuple:");
 			}
@@ -658,7 +658,7 @@ pg_decode_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 				appendStringInfoString(ctx->out, " (no-tuple-data)");
 			else
 				tuple_to_stringinfo(ctx->out, tupdesc,
-									&change->data.tp.newtuple->tuple,
+									change->data.tp.newtuple,
 									false);
 			break;
 		case REORDER_BUFFER_CHANGE_DELETE:
@@ -670,7 +670,7 @@ pg_decode_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 			/* In DELETE, only the replica identity is present; display that */
 			else
 				tuple_to_stringinfo(ctx->out, tupdesc,
-									&change->data.tp.oldtuple->tuple,
+									change->data.tp.oldtuple,
 									true);
 			break;
 		default:
diff --git a/src/backend/replication/logical/decode.c b/src/backend/replication/logical/decode.c
index 6a0f22b209b..7b21731287d 100644
--- a/src/backend/replication/logical/decode.c
+++ b/src/backend/replication/logical/decode.c
@@ -62,7 +62,7 @@ static void DecodePrepare(LogicalDecodingContext *ctx, XLogRecordBuffer *buf,
 
 
 /* common function to decode tuples */
-static void DecodeXLogTuple(char *data, Size len, ReorderBufferTupleBuf *tuple);
+static void DecodeXLogTuple(char *data, Size len, HeapTuple tuple);
 
 /* helper functions for decoding transactions */
 static inline bool FilterPrepare(LogicalDecodingContext *ctx,
@@ -1152,7 +1152,7 @@ DecodeMultiInsert(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
 		ReorderBufferChange *change;
 		xl_multi_insert_tuple *xlhdr;
 		int			datalen;
-		ReorderBufferTupleBuf *tuple;
+		HeapTuple	tuple;
 		HeapTupleHeader header;
 
 		change = ReorderBufferGetChange(ctx->reorder);
@@ -1169,21 +1169,21 @@ DecodeMultiInsert(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
 			ReorderBufferGetTupleBuf(ctx->reorder, datalen);
 
 		tuple = change->data.tp.newtuple;
-		header = tuple->tuple.t_data;
+		header = tuple->t_data;
 
 		/* not a disk based tuple */
-		ItemPointerSetInvalid(&tuple->tuple.t_self);
+		ItemPointerSetInvalid(&tuple->t_self);
 
 		/*
 		 * We can only figure this out after reassembling the transactions.
 		 */
-		tuple->tuple.t_tableOid = InvalidOid;
+		tuple->t_tableOid = InvalidOid;
 
-		tuple->tuple.t_len = datalen + SizeofHeapTupleHeader;
+		tuple->t_len = datalen + SizeofHeapTupleHeader;
 
 		memset(header, 0, SizeofHeapTupleHeader);
 
-		memcpy((char *) tuple->tuple.t_data + SizeofHeapTupleHeader,
+		memcpy((char *) tuple->t_data + SizeofHeapTupleHeader,
 			   (char *) data,
 			   datalen);
 		header->t_infomask = xlhdr->t_infomask;
@@ -1253,7 +1253,7 @@ DecodeSpecConfirm(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
  * computed outside as they are record specific.
  */
 static void
-DecodeXLogTuple(char *data, Size len, ReorderBufferTupleBuf *tuple)
+DecodeXLogTuple(char *data, Size len, HeapTuple tuple)
 {
 	xl_heap_header xlhdr;
 	int			datalen = len - SizeOfHeapHeader;
@@ -1261,14 +1261,14 @@ DecodeXLogTuple(char *data, Size len, ReorderBufferTupleBuf *tuple)
 
 	Assert(datalen >= 0);
 
-	tuple->tuple.t_len = datalen + SizeofHeapTupleHeader;
-	header = tuple->tuple.t_data;
+	tuple->t_len = datalen + SizeofHeapTupleHeader;
+	header = tuple->t_data;
 
 	/* not a disk based tuple */
-	ItemPointerSetInvalid(&tuple->tuple.t_self);
+	ItemPointerSetInvalid(&tuple->t_self);
 
 	/* we can only figure this out after reassembling the transactions */
-	tuple->tuple.t_tableOid = InvalidOid;
+	tuple->t_tableOid = InvalidOid;
 
 	/* data is not stored aligned, copy to aligned storage */
 	memcpy((char *) &xlhdr,
@@ -1277,7 +1277,7 @@ DecodeXLogTuple(char *data, Size len, ReorderBufferTupleBuf *tuple)
 
 	memset(header, 0, SizeofHeapTupleHeader);
 
-	memcpy(((char *) tuple->tuple.t_data) + SizeofHeapTupleHeader,
+	memcpy(((char *) tuple->t_data) + SizeofHeapTupleHeader,
 		   data + SizeOfHeapHeader,
 		   datalen);
 
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index d1334ffb550..bbf0966182f 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -498,13 +498,13 @@ ReorderBufferReturnChange(ReorderBuffer *rb, ReorderBufferChange *change,
 		case REORDER_BUFFER_CHANGE_INTERNAL_SPEC_INSERT:
 			if (change->data.tp.newtuple)
 			{
-				ReorderBufferReturnTupleBuf(rb, change->data.tp.newtuple);
+				ReorderBufferReturnTupleBuf(change->data.tp.newtuple);
 				change->data.tp.newtuple = NULL;
 			}
 
 			if (change->data.tp.oldtuple)
 			{
-				ReorderBufferReturnTupleBuf(rb, change->data.tp.oldtuple);
+				ReorderBufferReturnTupleBuf(change->data.tp.oldtuple);
 				change->data.tp.oldtuple = NULL;
 			}
 			break;
@@ -547,32 +547,29 @@ ReorderBufferReturnChange(ReorderBuffer *rb, ReorderBufferChange *change,
 }
 
 /*
- * Get a fresh ReorderBufferTupleBuf fitting at least a tuple of size
- * tuple_len (excluding header overhead).
+ * Get a fresh HeapTuple fitting a tuple of size tuple_len (excluding header
+ * overhead).
  */
-ReorderBufferTupleBuf *
+HeapTuple
 ReorderBufferGetTupleBuf(ReorderBuffer *rb, Size tuple_len)
 {
-	ReorderBufferTupleBuf *tuple;
+	HeapTuple	tuple;
 	Size		alloc_len;
 
 	alloc_len = tuple_len + SizeofHeapTupleHeader;
 
-	tuple = (ReorderBufferTupleBuf *)
-		MemoryContextAlloc(rb->tup_context,
-						   sizeof(ReorderBufferTupleBuf) +
-						   MAXIMUM_ALIGNOF + alloc_len);
-	tuple->alloc_tuple_size = alloc_len;
-	tuple->tuple.t_data = ReorderBufferTupleBufData(tuple);
+	tuple = (HeapTuple) MemoryContextAlloc(rb->tup_context,
+										   HEAPTUPLESIZE + alloc_len);
+	tuple->t_data = (HeapTupleHeader) ((char *) tuple + HEAPTUPLESIZE);
 
 	return tuple;
 }
 
 /*
- * Free a ReorderBufferTupleBuf.
+ * Free a HeapTuple returned by ReorderBufferGetTupleBuf().
  */
 void
-ReorderBufferReturnTupleBuf(ReorderBuffer *rb, ReorderBufferTupleBuf *tuple)
+ReorderBufferReturnTupleBuf(HeapTuple tuple)
 {
 	pfree(tuple);
 }
@@ -3759,8 +3756,8 @@ ReorderBufferSerializeChange(ReorderBuffer *rb, ReorderBufferTXN *txn,
 		case REORDER_BUFFER_CHANGE_INTERNAL_SPEC_INSERT:
 			{
 				char	   *data;
-				ReorderBufferTupleBuf *oldtup,
-						   *newtup;
+				HeapTuple	oldtup,
+							newtup;
 				Size		oldlen = 0;
 				Size		newlen = 0;
 
@@ -3770,14 +3767,14 @@ ReorderBufferSerializeChange(ReorderBuffer *rb, ReorderBufferTXN *txn,
 				if (oldtup)
 				{
 					sz += sizeof(HeapTupleData);
-					oldlen = oldtup->tuple.t_len;
+					oldlen = oldtup->t_len;
 					sz += oldlen;
 				}
 
 				if (newtup)
 				{
 					sz += sizeof(HeapTupleData);
-					newlen = newtup->tuple.t_len;
+					newlen = newtup->t_len;
 					sz += newlen;
 				}
 
@@ -3790,19 +3787,19 @@ ReorderBufferSerializeChange(ReorderBuffer *rb, ReorderBufferTXN *txn,
 
 				if (oldlen)
 				{
-					memcpy(data, &oldtup->tuple, sizeof(HeapTupleData));
+					memcpy(data, oldtup, sizeof(HeapTupleData));
 					data += sizeof(HeapTupleData);
 
-					memcpy(data, oldtup->tuple.t_data, oldlen);
+					memcpy(data, oldtup->t_data, oldlen);
 					data += oldlen;
 				}
 
 				if (newlen)
 				{
-					memcpy(data, &newtup->tuple, sizeof(HeapTupleData));
+					memcpy(data, newtup, sizeof(HeapTupleData));
 					data += sizeof(HeapTupleData);
 
-					memcpy(data, newtup->tuple.t_data, newlen);
+					memcpy(data, newtup->t_data, newlen);
 					data += newlen;
 				}
 				break;
@@ -4118,8 +4115,8 @@ ReorderBufferChangeSize(ReorderBufferChange *change)
 		case REORDER_BUFFER_CHANGE_DELETE:
 		case REORDER_BUFFER_CHANGE_INTERNAL_SPEC_INSERT:
 			{
-				ReorderBufferTupleBuf *oldtup,
-						   *newtup;
+				HeapTuple	oldtup,
+							newtup;
 				Size		oldlen = 0;
 				Size		newlen = 0;
 
@@ -4129,14 +4126,14 @@ ReorderBufferChangeSize(ReorderBufferChange *change)
 				if (oldtup)
 				{
 					sz += sizeof(HeapTupleData);
-					oldlen = oldtup->tuple.t_len;
+					oldlen = oldtup->t_len;
 					sz += oldlen;
 				}
 
 				if (newtup)
 				{
 					sz += sizeof(HeapTupleData);
-					newlen = newtup->tuple.t_len;
+					newlen = newtup->t_len;
 					sz += newlen;
 				}
 
@@ -4365,16 +4362,16 @@ ReorderBufferRestoreChange(ReorderBuffer *rb, ReorderBufferTXN *txn,
 					ReorderBufferGetTupleBuf(rb, tuplelen - SizeofHeapTupleHeader);
 
 				/* restore ->tuple */
-				memcpy(&change->data.tp.oldtuple->tuple, data,
+				memcpy(change->data.tp.oldtuple, data,
 					   sizeof(HeapTupleData));
 				data += sizeof(HeapTupleData);
 
 				/* reset t_data pointer into the new tuplebuf */
-				change->data.tp.oldtuple->tuple.t_data =
-					ReorderBufferTupleBufData(change->data.tp.oldtuple);
+				change->data.tp.oldtuple->t_data =
+					(HeapTupleHeader) ((char *) change->data.tp.oldtuple + HEAPTUPLESIZE);
 
 				/* restore tuple data itself */
-				memcpy(change->data.tp.oldtuple->tuple.t_data, data, tuplelen);
+				memcpy(change->data.tp.oldtuple->t_data, data, tuplelen);
 				data += tuplelen;
 			}
 
@@ -4390,16 +4387,16 @@ ReorderBufferRestoreChange(ReorderBuffer *rb, ReorderBufferTXN *txn,
 					ReorderBufferGetTupleBuf(rb, tuplelen - SizeofHeapTupleHeader);
 
 				/* restore ->tuple */
-				memcpy(&change->data.tp.newtuple->tuple, data,
+				memcpy(change->data.tp.newtuple, data,
 					   sizeof(HeapTupleData));
 				data += sizeof(HeapTupleData);
 
 				/* reset t_data pointer into the new tuplebuf */
-				change->data.tp.newtuple->tuple.t_data =
-					ReorderBufferTupleBufData(change->data.tp.newtuple);
+				change->data.tp.newtuple->t_data =
+					(HeapTupleHeader) ((char *) change->data.tp.newtuple + HEAPTUPLESIZE);
 
 				/* restore tuple data itself */
-				memcpy(change->data.tp.newtuple->tuple.t_data, data, tuplelen);
+				memcpy(change->data.tp.newtuple->t_data, data, tuplelen);
 				data += tuplelen;
 			}
 
@@ -4646,7 +4643,7 @@ ReorderBufferToastAppendChunk(ReorderBuffer *rb, ReorderBufferTXN *txn,
 							  Relation relation, ReorderBufferChange *change)
 {
 	ReorderBufferToastEnt *ent;
-	ReorderBufferTupleBuf *newtup;
+	HeapTuple	newtup;
 	bool		found;
 	int32		chunksize;
 	bool		isnull;
@@ -4661,9 +4658,9 @@ ReorderBufferToastAppendChunk(ReorderBuffer *rb, ReorderBufferTXN *txn,
 	Assert(IsToastRelation(relation));
 
 	newtup = change->data.tp.newtuple;
-	chunk_id = DatumGetObjectId(fastgetattr(&newtup->tuple, 1, desc, &isnull));
+	chunk_id = DatumGetObjectId(fastgetattr(newtup, 1, desc, &isnull));
 	Assert(!isnull);
-	chunk_seq = DatumGetInt32(fastgetattr(&newtup->tuple, 2, desc, &isnull));
+	chunk_seq = DatumGetInt32(fastgetattr(newtup, 2, desc, &isnull));
 	Assert(!isnull);
 
 	ent = (ReorderBufferToastEnt *)
@@ -4686,7 +4683,7 @@ ReorderBufferToastAppendChunk(ReorderBuffer *rb, ReorderBufferTXN *txn,
 		elog(ERROR, "got sequence entry %d for toast chunk %u instead of seq %d",
 			 chunk_seq, chunk_id, ent->last_chunk_seq + 1);
 
-	chunk = DatumGetPointer(fastgetattr(&newtup->tuple, 3, desc, &isnull));
+	chunk = DatumGetPointer(fastgetattr(newtup, 3, desc, &isnull));
 	Assert(!isnull);
 
 	/* calculate size so we can allocate the right size at once later */
@@ -4737,7 +4734,7 @@ ReorderBufferToastReplace(ReorderBuffer *rb, ReorderBufferTXN *txn,
 	Relation	toast_rel;
 	TupleDesc	toast_desc;
 	MemoryContext oldcontext;
-	ReorderBufferTupleBuf *newtup;
+	HeapTuple	newtup;
 	Size		old_size;
 
 	/* no toast tuples changed */
@@ -4777,7 +4774,7 @@ ReorderBufferToastReplace(ReorderBuffer *rb, ReorderBufferTXN *txn,
 
 	newtup = change->data.tp.newtuple;
 
-	heap_deform_tuple(&newtup->tuple, desc, attrs, isnull);
+	heap_deform_tuple(newtup, desc, attrs, isnull);
 
 	for (natt = 0; natt < desc->natts; natt++)
 	{
@@ -4842,12 +4839,12 @@ ReorderBufferToastReplace(ReorderBuffer *rb, ReorderBufferTXN *txn,
 		{
 			bool		cisnull;
 			ReorderBufferChange *cchange;
-			ReorderBufferTupleBuf *ctup;
+			HeapTuple	ctup;
 			Pointer		chunk;
 
 			cchange = dlist_container(ReorderBufferChange, node, it.cur);
 			ctup = cchange->data.tp.newtuple;
-			chunk = DatumGetPointer(fastgetattr(&ctup->tuple, 3, toast_desc, &cisnull));
+			chunk = DatumGetPointer(fastgetattr(ctup, 3, toast_desc, &cisnull));
 
 			Assert(!cisnull);
 			Assert(!VARATT_IS_EXTERNAL(chunk));
@@ -4882,11 +4879,11 @@ ReorderBufferToastReplace(ReorderBuffer *rb, ReorderBufferTXN *txn,
 	 * the tuplebuf because attrs[] will point back into the current content.
 	 */
 	tmphtup = heap_form_tuple(desc, attrs, isnull);
-	Assert(newtup->tuple.t_len <= MaxHeapTupleSize);
-	Assert(ReorderBufferTupleBufData(newtup) == newtup->tuple.t_data);
+	Assert(newtup->t_len <= MaxHeapTupleSize);
+	Assert(newtup->t_data == (HeapTupleHeader) ((char *) newtup + HEAPTUPLESIZE));
 
-	memcpy(newtup->tuple.t_data, tmphtup->t_data, tmphtup->t_len);
-	newtup->tuple.t_len = tmphtup->t_len;
+	memcpy(newtup->t_data, tmphtup->t_data, tmphtup->t_len);
+	newtup->t_len = tmphtup->t_len;
 
 	/*
 	 * free resources we won't further need, more persistent stuff will be
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 425238187f6..998f92d6712 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1473,7 +1473,7 @@ pgoutput_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 	if (change->data.tp.oldtuple)
 	{
 		old_slot = relentry->old_slot;
-		ExecStoreHeapTuple(&change->data.tp.oldtuple->tuple, old_slot, false);
+		ExecStoreHeapTuple(change->data.tp.oldtuple, old_slot, false);
 
 		/* Convert tuple if needed. */
 		if (relentry->attrmap)
@@ -1488,7 +1488,7 @@ pgoutput_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 	if (change->data.tp.newtuple)
 	{
 		new_slot = relentry->new_slot;
-		ExecStoreHeapTuple(&change->data.tp.newtuple->tuple, new_slot, false);
+		ExecStoreHeapTuple(change->data.tp.newtuple, new_slot, false);
 
 		/* Convert tuple if needed. */
 		if (relentry->attrmap)
diff --git a/src/include/replication/reorderbuffer.h b/src/include/replication/reorderbuffer.h
index 3e232c6c27f..0b2c95f7aa0 100644
--- a/src/include/replication/reorderbuffer.h
+++ b/src/include/replication/reorderbuffer.h
@@ -28,25 +28,6 @@ typedef enum
 	DEBUG_LOGICAL_REP_STREAMING_IMMEDIATE,
 }			DebugLogicalRepStreamingMode;
 
-/* an individual tuple, stored in one chunk of memory */
-typedef struct ReorderBufferTupleBuf
-{
-	/* position in preallocated list */
-	slist_node	node;
-
-	/* tuple header, the interesting bit for users of logical decoding */
-	HeapTupleData tuple;
-
-	/* pre-allocated size of tuple buffer, different from tuple size */
-	Size		alloc_tuple_size;
-
-	/* actual tuple data follows */
-} ReorderBufferTupleBuf;
-
-/* pointer to the data stored in a TupleBuf */
-#define ReorderBufferTupleBufData(p) \
-	((HeapTupleHeader) MAXALIGN(((char *) p) + sizeof(ReorderBufferTupleBuf)))
-
 /*
  * Types of the change passed to a 'change' callback.
  *
@@ -114,9 +95,9 @@ typedef struct ReorderBufferChange
 			bool		clear_toast_afterwards;
 
 			/* valid for DELETE || UPDATE */
-			ReorderBufferTupleBuf *oldtuple;
+			HeapTuple	oldtuple;
 			/* valid for INSERT || UPDATE */
-			ReorderBufferTupleBuf *newtuple;
+			HeapTuple	newtuple;
 		}			tp;
 
 		/*
@@ -678,10 +659,10 @@ struct ReorderBuffer
 extern ReorderBuffer *ReorderBufferAllocate(void);
 extern void ReorderBufferFree(ReorderBuffer *rb);
 
-extern ReorderBufferTupleBuf *ReorderBufferGetTupleBuf(ReorderBuffer *rb,
-													   Size tuple_len);
-extern void ReorderBufferReturnTupleBuf(ReorderBuffer *rb,
-										ReorderBufferTupleBuf *tuple);
+extern HeapTuple ReorderBufferGetTupleBuf(ReorderBuffer *rb,
+										  Size tuple_len);
+extern void ReorderBufferReturnTupleBuf(HeapTuple tuple);
+
 extern ReorderBufferChange *ReorderBufferGetChange(ReorderBuffer *rb);
 extern void ReorderBufferReturnChange(ReorderBuffer *rb,
 									  ReorderBufferChange *change, bool upd_mem);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 7e866e3c3d0..dc3b0ef8710 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2351,7 +2351,6 @@ ReorderBufferStreamTruncateCB
 ReorderBufferTXN
 ReorderBufferTXNByIdEnt
 ReorderBufferToastEnt
-ReorderBufferTupleBuf
 ReorderBufferTupleCidEnt
 ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB