From f2110a757d0bdca766fa1b8562c7dcb1a53fd422 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 5 Apr 2009 22:28:59 +0000
Subject: Change cardinality() into a C-code function, instead of a
 SQL-language alias for array_length(v,1).  The efficiency gain here is
 doubtless negligible --- what I'm interested in is making sure that if we
 have second thoughts about the definition, we will not have to force a
 post-beta initdb to change the implementation.

---
 src/backend/utils/adt/arrayfuncs.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

(limited to 'src/backend/utils/adt/arrayfuncs.c')

diff --git a/src/backend/utils/adt/arrayfuncs.c b/src/backend/utils/adt/arrayfuncs.c
index 111d6b8c263..8b36edc42fa 100644
--- a/src/backend/utils/adt/arrayfuncs.c
+++ b/src/backend/utils/adt/arrayfuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.153 2009/01/30 21:21:18 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.154 2009/04/05 22:28:59 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1668,6 +1668,28 @@ array_length(PG_FUNCTION_ARGS)
 	PG_RETURN_INT32(result);
 }
 
+/*
+ * array_cardinality :
+ *		SQL-spec alias for array_length(v, 1)
+ */
+Datum
+array_cardinality(PG_FUNCTION_ARGS)
+{
+	ArrayType  *v = PG_GETARG_ARRAYTYPE_P(0);
+	int		   *dimv;
+	int			result;
+
+	/* Sanity check: does it look like an array at all? */
+	if (ARR_NDIM(v) <= 0 || ARR_NDIM(v) > MAXDIM)
+		PG_RETURN_NULL();
+
+	dimv = ARR_DIMS(v);
+
+	result = dimv[0];
+
+	PG_RETURN_INT32(result);
+}
+
 /*
  * array_ref :
  *	  This routine takes an array pointer and a subscript array and returns
-- 
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