3 files changed, 48 insertions, 0 deletions
diff --git a/src/test/regress/expected/misc_functions.out b/src/test/regress/expected/misc_functions.out
index 106dedb519a..543fbbe09c5 100644
--- a/src/test/regress/expected/misc_functions.out
+++ b/src/test/regress/expected/misc_functions.out
@@ -903,3 +903,14 @@ SELECT gist_stratnum_common(3);
                    18
 (1 row)
 
+-- relpath tests
+CREATE FUNCTION test_relpath()
+    RETURNS void
+    AS :'regresslib'
+    LANGUAGE C;
+SELECT test_relpath();
+ test_relpath 
+--------------
+ 
+(1 row)
+
diff --git a/src/test/regress/regress.c b/src/test/regress/regress.c
index 667d9835148..ed4a7937331 100644
--- a/src/test/regress/regress.c
+++ b/src/test/regress/regress.c
@@ -36,6 +36,7 @@
 #include "optimizer/plancat.h"
 #include "parser/parse_coerce.h"
 #include "port/atomics.h"
+#include "postmaster/postmaster.h"	/* for MAX_BACKENDS */
 #include "storage/spin.h"
 #include "utils/array.h"
 #include "utils/builtins.h"
@@ -1208,3 +1209,31 @@ binary_coercible(PG_FUNCTION_ARGS)
 
 	PG_RETURN_BOOL(IsBinaryCoercible(srctype, targettype));
 }
+
+/*
+ * Sanity checks for functions in relpath.h
+ */
+PG_FUNCTION_INFO_V1(test_relpath);
+Datum
+test_relpath(PG_FUNCTION_ARGS)
+{
+	RelPathStr	rpath;
+
+	/*
+	 * Verify that PROCNUMBER_CHARS and MAX_BACKENDS stay in sync.
+	 * Unfortunately I don't know how to express that in a way suitable for a
+	 * static assert.
+	 */
+	if ((int) ceil(log10(MAX_BACKENDS)) != PROCNUMBER_CHARS)
+		elog(WARNING, "mismatch between MAX_BACKENDS and PROCNUMBER_CHARS");
+
+	/* verify that the max-length relpath is generated ok */
+	rpath = GetRelationPath(OID_MAX, OID_MAX, OID_MAX, MAX_BACKENDS - 1,
+							INIT_FORKNUM);
+
+	if (strlen(rpath.str) != REL_PATH_STR_MAXLEN)
+		elog(WARNING, "maximum length relpath is if length %zu instead of %zu",
+			 strlen(rpath.str), REL_PATH_STR_MAXLEN);
+
+	PG_RETURN_VOID();
+}
diff --git a/src/test/regress/sql/misc_functions.sql b/src/test/regress/sql/misc_functions.sql
index 753a0f41c03..aaebb298330 100644
--- a/src/test/regress/sql/misc_functions.sql
+++ b/src/test/regress/sql/misc_functions.sql
@@ -403,3 +403,11 @@ DROP FUNCTION explain_mask_costs(text, bool, bool, bool, bool);
 -- test stratnum support functions
 SELECT gist_stratnum_common(7);
 SELECT gist_stratnum_common(3);
+
+
+-- relpath tests
+CREATE FUNCTION test_relpath()
+    RETURNS void
+    AS :'regresslib'
+    LANGUAGE C;
+SELECT test_relpath();