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, 51 insertions, 1 deletions

diff --git a/contrib/btree_gist/btree_float8.c b/contrib/btree_gist/btree_float8.c
index 1386983272c..0c39980ba1e 100644
--- a/contrib/btree_gist/btree_float8.c
+++ b/contrib/btree_gist/btree_float8.c
@@ -17,6 +17,7 @@ PG_FUNCTION_INFO_V1(gbt_float8_compress);
 PG_FUNCTION_INFO_V1(gbt_float8_union);
 PG_FUNCTION_INFO_V1(gbt_float8_picksplit);
 PG_FUNCTION_INFO_V1(gbt_float8_consistent);
+PG_FUNCTION_INFO_V1(gbt_float8_distance);
 PG_FUNCTION_INFO_V1(gbt_float8_penalty);
 PG_FUNCTION_INFO_V1(gbt_float8_same);
 
@@ -24,6 +25,7 @@ Datum		gbt_float8_compress(PG_FUNCTION_ARGS);
 Datum		gbt_float8_union(PG_FUNCTION_ARGS);
 Datum		gbt_float8_picksplit(PG_FUNCTION_ARGS);
 Datum		gbt_float8_consistent(PG_FUNCTION_ARGS);
+Datum		gbt_float8_distance(PG_FUNCTION_ARGS);
 Datum		gbt_float8_penalty(PG_FUNCTION_ARGS);
 Datum		gbt_float8_same(PG_FUNCTION_ARGS);
 
@@ -71,6 +73,19 @@ gbt_float8key_cmp(const void *a, const void *b)
 	return (ia->lower > ib->lower) ? 1 : -1;
 }
 
+static float8
+gbt_float8_dist(const void *a, const void *b)
+{
+	float8		arg1 = *(const float8 *)a;
+	float8		arg2 = *(const float8 *)b;
+	float8		r;
+
+	r = arg1 - arg2;
+	CHECKFLOATVAL(r, isinf(arg1) || isinf(arg2), true);
+
+	return Abs(r);
+}
+
 
 static const gbtree_ninfo tinfo =
 {
@@ -81,10 +96,26 @@ static const gbtree_ninfo tinfo =
 	gbt_float8eq,
 	gbt_float8le,
 	gbt_float8lt,
-	gbt_float8key_cmp
+	gbt_float8key_cmp,
+	gbt_float8_dist
 };
 
 
+PG_FUNCTION_INFO_V1(float8_dist);
+Datum       float8_dist(PG_FUNCTION_ARGS);
+Datum
+float8_dist(PG_FUNCTION_ARGS)
+{
+	float8		a = PG_GETARG_FLOAT8(0);
+	float8		b = PG_GETARG_FLOAT8(1);
+	float8		r;
+
+	r = a - b;
+	CHECKFLOATVAL(r, isinf(a) || isinf(b), true);
+
+	PG_RETURN_FLOAT8( Abs(r) );
+}
+
 /**************************************************
  * float8 ops
  **************************************************/
@@ -125,6 +156,25 @@ gbt_float8_consistent(PG_FUNCTION_ARGS)
 
 
 Datum
+gbt_float8_distance(PG_FUNCTION_ARGS)
+{
+	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
+	float8		query = PG_GETARG_FLOAT8(1);
+
+	/* Oid		subtype = PG_GETARG_OID(3); */
+	float8KEY  *kkk = (float8KEY *) 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_float8_union(PG_FUNCTION_ARGS)
 {
 	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);