Add KNNGIST support to contrib/btree_gist.

This extends GiST's support for nearest-neighbor searches to many of the
standard data types.

Teodor Sigaev

1 files changed, 52 insertions, 1 deletions

diff --git a/contrib/btree_gist/btree_int4.c b/contrib/btree_gist/btree_int4.c
index 678d653fd0b..ef7af524e76 100644
--- a/contrib/btree_gist/btree_int4.c
+++ b/contrib/btree_gist/btree_int4.c
@@ -17,6 +17,7 @@ PG_FUNCTION_INFO_V1(gbt_int4_compress);
 PG_FUNCTION_INFO_V1(gbt_int4_union);
 PG_FUNCTION_INFO_V1(gbt_int4_picksplit);
 PG_FUNCTION_INFO_V1(gbt_int4_consistent);
+PG_FUNCTION_INFO_V1(gbt_int4_distance);
 PG_FUNCTION_INFO_V1(gbt_int4_penalty);
 PG_FUNCTION_INFO_V1(gbt_int4_same);
 
@@ -24,6 +25,7 @@ Datum		gbt_int4_compress(PG_FUNCTION_ARGS);
 Datum		gbt_int4_union(PG_FUNCTION_ARGS);
 Datum		gbt_int4_picksplit(PG_FUNCTION_ARGS);
 Datum		gbt_int4_consistent(PG_FUNCTION_ARGS);
+Datum		gbt_int4_distance(PG_FUNCTION_ARGS);
 Datum		gbt_int4_penalty(PG_FUNCTION_ARGS);
 Datum		gbt_int4_same(PG_FUNCTION_ARGS);
 
@@ -71,6 +73,12 @@ gbt_int4key_cmp(const void *a, const void *b)
 	return (ia->lower > ib->lower) ? 1 : -1;
 }
 
+static float8
+gbt_int4_dist(const void *a, const void *b)
+{
+	return GET_FLOAT_DISTANCE(int4, a, b);
+}
+
 
 static const gbtree_ninfo tinfo =
 {
@@ -81,10 +89,34 @@ static const gbtree_ninfo tinfo =
 	gbt_int4eq,
 	gbt_int4le,
 	gbt_int4lt,
-	gbt_int4key_cmp
+	gbt_int4key_cmp,
+	gbt_int4_dist
 };
 
 
+PG_FUNCTION_INFO_V1(int4_dist);
+Datum       int4_dist(PG_FUNCTION_ARGS);
+Datum
+int4_dist(PG_FUNCTION_ARGS)
+{
+	int4        a = PG_GETARG_INT32(0);
+	int4        b = PG_GETARG_INT32(1);
+	int4        r;
+	int4        ra;
+
+	r = a - b;
+	ra = Abs(r);
+
+	/* Overflow check. */
+	if (ra < 0 || (!SAMESIGN(a, b) && !SAMESIGN(r, a)))
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+						 errmsg("integer out of range")));
+
+	PG_RETURN_INT32(ra);
+}
+
+
 /**************************************************
  * int32 ops
  **************************************************/
@@ -125,6 +157,25 @@ gbt_int4_consistent(PG_FUNCTION_ARGS)
 
 
 Datum
+gbt_int4_distance(PG_FUNCTION_ARGS)
+{
+	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
+	int32		query = PG_GETARG_INT32(1);
+
+	/* Oid		subtype = PG_GETARG_OID(3); */
+	int32KEY   *kkk = (int32KEY *) DatumGetPointer(entry->key);
+	GBT_NUMKEY_R key;
+
+	key.lower = (GBT_NUMKEY *) &kkk->lower;
+	key.upper = (GBT_NUMKEY *) &kkk->upper;
+
+	PG_RETURN_FLOAT8(
+				   gbt_num_distance(&key, (void *) &query, GIST_LEAF(entry), &tinfo)
+		);
+}
+
+
+Datum
 gbt_int4_union(PG_FUNCTION_ARGS)
 {
 	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);