Function DecodeDelete

src/backend/replication/logical/decode.c:973–1022

* Parse XLOG_HEAP_DELETE from wal into proper tuplebufs. * * Deletes can possibly contain the old primary key. */

 * Deletes can possibly contain the old primary key.
 */
static void
DecodeDelete(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
{
	XLogReaderState *r = buf->record;
	xl_heap_delete *xlrec;
	ReorderBufferChange *change;
	RelFileNode target_node;

	xlrec = (xl_heap_delete *) XLogRecGetData(r);

	/* only interested in our database */
	XLogRecGetBlockTag(r, 0, &target_node, NULL, NULL);
	if (target_node.dbNode != ctx->slot->data.database)
		return;

	/* output plugin doesn't look for this origin, no need to queue */
	if (FilterByOrigin(ctx, XLogRecGetOrigin(r)))
		return;

	change = ReorderBufferGetChange(ctx->reorder);

	if (xlrec->flags & XLH_DELETE_IS_SUPER)
		change->action = REORDER_BUFFER_CHANGE_INTERNAL_SPEC_ABORT;
	else
		change->action = REORDER_BUFFER_CHANGE_DELETE;

	change->origin_id = XLogRecGetOrigin(r);

	memcpy(&change->data.tp.relnode, &target_node, sizeof(RelFileNode));

	/* old primary key stored */
	if (xlrec->flags & XLH_DELETE_CONTAINS_OLD)
	{
		Size		datalen = XLogRecGetDataLen(r) - SizeOfHeapDelete;
		Size		tuplelen = datalen - SizeOfHeapHeader;

		Assert(XLogRecGetDataLen(r) > (SizeOfHeapDelete + SizeOfHeapHeader));

		change->data.tp.oldtuple =
			ReorderBufferGetTupleBuf(ctx->reorder, tuplelen);

		DecodeXLogTuple((char *) xlrec + SizeOfHeapDelete,
						datalen, change->data.tp.oldtuple);
	}

	change->data.tp.clear_toast_afterwards = true;

	ReorderBufferQueueChange(ctx->reorder, XLogRecGetXid(r), buf->origptr,
							 change, false);
}

/*
 * Parse XLOG_HEAP_TRUNCATE from wal