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, 56 insertions, 1 deletions

diff --git a/contrib/btree_gist/btree_interval.c b/contrib/btree_gist/btree_interval.c
index 0715346f234..5195284afa1 100644
--- a/contrib/btree_gist/btree_interval.c
+++ b/contrib/btree_gist/btree_interval.c
@@ -20,6 +20,7 @@ PG_FUNCTION_INFO_V1(gbt_intv_decompress);
 PG_FUNCTION_INFO_V1(gbt_intv_union);
 PG_FUNCTION_INFO_V1(gbt_intv_picksplit);
 PG_FUNCTION_INFO_V1(gbt_intv_consistent);
+PG_FUNCTION_INFO_V1(gbt_intv_distance);
 PG_FUNCTION_INFO_V1(gbt_intv_penalty);
 PG_FUNCTION_INFO_V1(gbt_intv_same);
 
@@ -28,6 +29,7 @@ Datum		gbt_intv_decompress(PG_FUNCTION_ARGS);
 Datum		gbt_intv_union(PG_FUNCTION_ARGS);
 Datum		gbt_intv_picksplit(PG_FUNCTION_ARGS);
 Datum		gbt_intv_consistent(PG_FUNCTION_ARGS);
+Datum		gbt_intv_distance(PG_FUNCTION_ARGS);
 Datum		gbt_intv_penalty(PG_FUNCTION_ARGS);
 Datum		gbt_intv_same(PG_FUNCTION_ARGS);
 
@@ -83,6 +85,12 @@ intr2num(const Interval *i)
 	return INTERVAL_TO_SEC(i);
 }
 
+static float8
+gbt_intv_dist(const void *a, const void *b)
+{
+	return (float8)Abs(intr2num((Interval*)a) - intr2num((Interval*)b));
+}
+
 /*
  * INTERVALSIZE should be the actual size-on-disk of an Interval, as shown
  * in pg_type.	This might be less than sizeof(Interval) if the compiler
@@ -99,10 +107,38 @@ static const gbtree_ninfo tinfo =
 	gbt_intveq,
 	gbt_intvle,
 	gbt_intvlt,
-	gbt_intvkey_cmp
+	gbt_intvkey_cmp,
+	gbt_intv_dist
 };
 
 
+Interval *
+abs_interval(Interval *a)
+{
+	static Interval zero = {0, 0, 0};
+
+	if (DatumGetBool(DirectFunctionCall2(interval_lt,
+										 IntervalPGetDatum(a),
+										 IntervalPGetDatum(&zero))))
+		a = DatumGetIntervalP(DirectFunctionCall1(interval_um,
+												  IntervalPGetDatum(a)));
+
+	return a;
+}
+
+PG_FUNCTION_INFO_V1(interval_dist);
+Datum       interval_dist(PG_FUNCTION_ARGS);
+Datum
+interval_dist(PG_FUNCTION_ARGS)
+{
+	Datum		diff = DirectFunctionCall2(interval_mi,
+										   PG_GETARG_DATUM(0),
+										   PG_GETARG_DATUM(1));
+
+	PG_RETURN_INTERVAL_P(abs_interval(DatumGetIntervalP(diff)));
+}
+
+
 /**************************************************
  * interval ops
  **************************************************/
@@ -191,6 +227,25 @@ gbt_intv_consistent(PG_FUNCTION_ARGS)
 
 
 Datum
+gbt_intv_distance(PG_FUNCTION_ARGS)
+{
+	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
+	Interval   *query = PG_GETARG_INTERVAL_P(1);
+
+	/* Oid		subtype = PG_GETARG_OID(3); */
+	intvKEY    *kkk = (intvKEY *) 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_intv_union(PG_FUNCTION_ARGS)
 {
 	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);