diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5338387..92db86f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.4.1 (unreleased)
+
+- Added `random_vector` function
+
 ## 0.4.0 (2023-01-11)
 
 If upgrading with Postgres < 13, see [this note](https://github.com/pgvector/pgvector#040).
diff --git a/README.md b/README.md
index 5a7babf..7991949 100644
--- a/README.md
+++ b/README.md
@@ -184,6 +184,7 @@ inner_product(vector, vector) → double precision | inner product
 l2_distance(vector, vector) → double precision | Euclidean distance
 vector_dims(vector) → integer | number of dimensions
 vector_norm(vector) → double precision | Euclidean norm
+random_vector(integer) → vector | random vector [unreleased]
 
 ### Aggregate Functions
 
diff --git a/sql/vector--0.4.0--0.4.1.sql b/sql/vector--0.4.0--0.4.1.sql
new file mode 100644
index 0000000..8661aff
--- /dev/null
+++ b/sql/vector--0.4.0--0.4.1.sql
@@ -0,0 +1,5 @@
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "ALTER EXTENSION vector UPDATE TO '0.4.1'" to load this file. \quit
+
+CREATE FUNCTION random_vector(integer) RETURNS vector
+	AS 'MODULE_PATHNAME' LANGUAGE C VOLATILE STRICT PARALLEL SAFE;
diff --git a/sql/vector.sql b/sql/vector.sql
index 6188e2e..dc7fefb 100644
--- a/sql/vector.sql
+++ b/sql/vector.sql
@@ -52,6 +52,9 @@ CREATE FUNCTION vector_add(vector, vector) RETURNS vector
 CREATE FUNCTION vector_sub(vector, vector) RETURNS vector
 	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
 
+CREATE FUNCTION random_vector(integer) RETURNS vector
+	AS 'MODULE_PATHNAME' LANGUAGE C VOLATILE STRICT PARALLEL SAFE;
+
 -- private functions
 
 CREATE FUNCTION vector_lt(vector, vector) RETURNS bool
diff --git a/src/ivfflat.h b/src/ivfflat.h
index 5bd7622..3918b94 100644
--- a/src/ivfflat.h
+++ b/src/ivfflat.h
@@ -10,15 +10,10 @@
 #include "access/generic_xlog.h"
 #include "access/reloptions.h"
 #include "nodes/execnodes.h"
-#include "port.h"				/* for strtof() and random() */
 #include "utils/sampling.h"
 #include "utils/tuplesort.h"
 #include "vector.h"
 
-#if PG_VERSION_NUM >= 150000
-#include "common/pg_prng.h"
-#endif
-
 #ifdef IVFFLAT_BENCH
 #include "portability/instr_time.h"
 #endif
@@ -68,14 +63,6 @@
 #define IvfflatBench(name, code) (code)
 #endif
 
-#if PG_VERSION_NUM >= 150000
-#define RandomDouble() pg_prng_double(&pg_global_prng_state)
-#define RandomInt() pg_prng_uint32(&pg_global_prng_state)
-#else
-#define RandomDouble() (((double) random()) / MAX_RANDOM_VALUE)
-#define RandomInt() random()
-#endif
-
 /* Variables */
 extern int	ivfflat_probes;
 
diff --git a/src/vector.c b/src/vector.c
index d232a23..0ea2574 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -950,3 +950,22 @@ vector_avg(PG_FUNCTION_ARGS)
 
 	PG_RETURN_POINTER(result);
 }
+
+/*
+ * Generate a random vector
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(random_vector);
+Datum
+random_vector(PG_FUNCTION_ARGS)
+{
+	int32		dim = PG_GETARG_INT32(0);
+	Vector	   *result;
+
+	CheckDim(dim);
+
+	result = InitVector(dim);
+	for (int i = 0; i < dim; i++)
+		result->x[i] = RandomDouble();
+
+	PG_RETURN_POINTER(result);
+}
diff --git a/src/vector.h b/src/vector.h
index 3e41130..ca04971 100644
--- a/src/vector.h
+++ b/src/vector.h
@@ -3,6 +3,12 @@
 
 #include "postgres.h"
 
+#include "port.h"				/* for strtof() and random() */
+
+#if PG_VERSION_NUM >= 150000
+#include "common/pg_prng.h"
+#endif
+
 #define VECTOR_MAX_DIM 16000
 
 #define VECTOR_SIZE(_dim)		(offsetof(Vector, x) + sizeof(float)*(_dim))
@@ -10,6 +16,14 @@
 #define PG_GETARG_VECTOR_P(x)	DatumGetVector(PG_GETARG_DATUM(x))
 #define PG_RETURN_VECTOR_P(x)	PG_RETURN_POINTER(x)
 
+#if PG_VERSION_NUM >= 150000
+#define RandomDouble() pg_prng_double(&pg_global_prng_state)
+#define RandomInt() pg_prng_uint32(&pg_global_prng_state)
+#else
+#define RandomDouble() (((double) random()) / MAX_RANDOM_VALUE)
+#define RandomInt() random()
+#endif
+
 typedef struct Vector
 {
 	int32		vl_len_;		/* varlena header (do not touch directly!) */
diff --git a/test/t/001_wal.pl b/test/t/001_wal.pl
index 46060ed..f9fc4df 100644
--- a/test/t/001_wal.pl
+++ b/test/t/001_wal.pl
@@ -44,11 +44,6 @@ sub test_index_replay
 	return;
 }
 
-# Use ARRAY[random(), random(), random(), ...] over
-# SELECT array_agg(random()) FROM generate_series(1, $dim)
-# to generate different values for each row
-my $array_sql = join(",", ('random()') x $dim);
-
 # Initialize primary node
 $node_primary = get_new_node('primary');
 $node_primary->init(allows_streaming => 1);
@@ -75,7 +70,7 @@ $node_replica->start;
 $node_primary->safe_psql("postgres", "CREATE EXTENSION vector;");
 $node_primary->safe_psql("postgres", "CREATE TABLE tst (i int4, v vector($dim));");
 $node_primary->safe_psql("postgres",
-	"INSERT INTO tst SELECT i % 10, ARRAY[$array_sql] FROM generate_series(1, 100000) i;"
+	"INSERT INTO tst SELECT i % 10, random_vector($dim) FROM generate_series(1, 100000) i;"
 );
 $node_primary->safe_psql("postgres", "CREATE INDEX ON tst USING ivfflat (v);");
 
@@ -91,7 +86,7 @@ for my $i (1 .. 10)
 	test_index_replay("vacuum $i");
 	my ($start, $end) = (100001 + ($i - 1) * 10000, 100000 + $i * 10000);
 	$node_primary->safe_psql("postgres",
-		"INSERT INTO tst SELECT i % 10, ARRAY[$array_sql] FROM generate_series($start, $end) i;"
+		"INSERT INTO tst SELECT i % 10, random_vector($dim) FROM generate_series($start, $end) i;"
 	);
 	test_index_replay("insert $i");
 }
diff --git a/test/t/003_recall.pl b/test/t/003_recall.pl
index dddc4d5..c5012bc 100644
--- a/test/t/003_recall.pl
+++ b/test/t/003_recall.pl
@@ -46,7 +46,7 @@ $node->start;
 $node->safe_psql("postgres", "CREATE EXTENSION vector;");
 $node->safe_psql("postgres", "CREATE TABLE tst (i int4, v vector(3));");
 $node->safe_psql("postgres",
-	"INSERT INTO tst SELECT i, ARRAY[random(), random(), random()] FROM generate_series(1, 100000) i;"
+	"INSERT INTO tst SELECT i, random_vector(3) FROM generate_series(1, 100000) i;"
 );
 
 # Generate queries
diff --git a/test/t/005_query_recall.pl b/test/t/005_query_recall.pl
index 0e58135..1cc1cd0 100644
--- a/test/t/005_query_recall.pl
+++ b/test/t/005_query_recall.pl
@@ -13,7 +13,7 @@ $node->start;
 $node->safe_psql("postgres", "CREATE EXTENSION vector;");
 $node->safe_psql("postgres", "CREATE TABLE tst (i int4 primary key, v vector(3));");
 $node->safe_psql("postgres",
-	"INSERT INTO tst SELECT i, ARRAY[random(), random(), random()] FROM generate_series(1, 100000) i;"
+	"INSERT INTO tst SELECT i, random_vector(3) FROM generate_series(1, 100000) i;"
 );
 
 # Check each index type
diff --git a/test/t/006_lists.pl b/test/t/006_lists.pl
index eeb11aa..d0a2059 100644
--- a/test/t/006_lists.pl
+++ b/test/t/006_lists.pl
@@ -13,7 +13,7 @@ $node->start;
 $node->safe_psql("postgres", "CREATE EXTENSION vector;");
 $node->safe_psql("postgres", "CREATE TABLE tst (v vector(3));");
 $node->safe_psql("postgres",
-	"INSERT INTO tst SELECT ARRAY[random(), random(), random()] FROM generate_series(1, 100000) i;"
+	"INSERT INTO tst SELECT random_vector(3) FROM generate_series(1, 100000) i;"
 );
 
 $node->safe_psql("postgres", "CREATE INDEX lists50 ON tst USING ivfflat (v) WITH (lists = 50);");
diff --git a/test/t/007_inserts.pl b/test/t/007_inserts.pl
index 85f354c..b9b93c9 100644
--- a/test/t/007_inserts.pl
+++ b/test/t/007_inserts.pl
@@ -6,8 +6,6 @@ use Test::More tests => 5;
 
 my $dim = 768;
 
-my $array_sql = join(",", ('random()') x $dim);
-
 # Initialize node
 my $node = get_new_node('node');
 $node->init;
@@ -17,7 +15,7 @@ $node->start;
 $node->safe_psql("postgres", "CREATE EXTENSION vector;");
 $node->safe_psql("postgres", "CREATE TABLE tst (v vector($dim));");
 $node->safe_psql("postgres",
-	"INSERT INTO tst SELECT ARRAY[$array_sql] FROM generate_series(1, 10000) i;"
+	"INSERT INTO tst SELECT random_vector($dim) FROM generate_series(1, 10000) i;"
 );
 $node->safe_psql("postgres", "CREATE INDEX ON tst USING ivfflat (v);");
 
@@ -28,7 +26,7 @@ $node->pgbench(
 	[qr{^$}],
 	"concurrent INSERTs",
 	{
-		"007_inserts" => "INSERT INTO tst SELECT ARRAY[$array_sql] FROM generate_series(1, 10) i;"
+		"007_inserts" => "INSERT INTO tst SELECT random_vector($dim) FROM generate_series(1, 10) i;"
 	}
 );
 
diff --git a/test/t/009_storage.pl b/test/t/009_storage.pl
index de818c7..b63e3a2 100644
--- a/test/t/009_storage.pl
+++ b/test/t/009_storage.pl
@@ -17,7 +17,7 @@ $node->safe_psql("postgres", "CREATE TABLE tst (v1 vector(1024), v2 vector(1024)
 
 # Test insert succeeds
 $node->safe_psql("postgres",
-	"INSERT INTO tst SELECT array_agg(n), array_agg(n), array_agg(n) FROM generate_series(1, $dim) n"
+	"INSERT INTO tst SELECT random_vector($dim), random_vector($dim), random_vector($dim)"
 );
 
 # Change storage to PLAIN
@@ -27,6 +27,6 @@ $node->safe_psql("postgres", "ALTER TABLE tst ALTER COLUMN v3 SET STORAGE PLAIN"
 
 # Test insert fails
 my ($ret, $stdout, $stderr) = $node->psql("postgres",
-	"INSERT INTO tst SELECT array_agg(n), array_agg(n), array_agg(n) FROM generate_series(1, $dim) n"
+	"INSERT INTO tst SELECT random_vector($dim), random_vector($dim), random_vector($dim)"
 );
 like($stderr, qr/row is too big/);