1 files changed, 40 insertions, 0 deletions
diff --git a/src/backend/access/tablesample/tablesample.c b/src/backend/access/tablesample/tablesample.c
new file mode 100644
index 0000000..7c3b9d4
--- /dev/null
+++ b/src/backend/access/tablesample/tablesample.c
@@ -0,0 +1,40 @@
+/*-------------------------------------------------------------------------
+ *
+ * tablesample.c
+ *		  Support functions for TABLESAMPLE feature
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *		  src/backend/access/tablesample/tablesample.c
+ *
+ * -------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/tsmapi.h"
+
+
+/*
+ * GetTsmRoutine --- get a TsmRoutine struct by invoking the handler.
+ *
+ * This is a convenience routine that's just meant to check for errors.
+ */
+TsmRoutine *
+GetTsmRoutine(Oid tsmhandler)
+{
+	Datum		datum;
+	TsmRoutine *routine;
+
+	datum = OidFunctionCall1(tsmhandler, PointerGetDatum(NULL));
+	routine = (TsmRoutine *) DatumGetPointer(datum);
+
+	if (routine == NULL || !IsA(routine, TsmRoutine))
+		elog(ERROR, "tablesample handler function %u did not return a TsmRoutine struct",
+			 tsmhandler);
+
+	return routine;
+}