Clean up a couple of box gist helper functions.

The original idea of this patch was to make box picksplit run faster, by
eliminating unnecessary palloc() overhead, but that was obsoleted by the new
double-sorting split algorithm that doesn't call these functions so heavily
anymore. Nevertheless, the code looks better this way.

Original patch by me, reviewed and tidied up after the double-sorting patch
by Kevin Grittner.

diff --git a/src/backend/access/gist/gistproc.c b/src/backend/access/gist/gistproc.c
index f7eb9412f90fb53056683cd3dd04d24652b940ee..2b68e218a45a08918129ee6a3ed4ffb2e71bb2c2 100644 (file)
--- a/src/backend/access/gist/gistproc.c
+++ b/src/backend/access/gist/gistproc.c
@@ -23,7 +23,7 @@
 
 static bool gist_box_leaf_consistent(BOX *key, BOX *query,
                         StrategyNumber strategy);
-static double size_box(Datum dbox);
+static double size_box(BOX *box);
 static bool rtree_internal_consistent(BOX *key, BOX *query,
                          StrategyNumber strategy);
 
@@ -35,21 +35,16 @@ static bool rtree_internal_consistent(BOX *key, BOX *query,
  * Box ops
  **************************************************/
 
-static Datum
-rt_box_union(PG_FUNCTION_ARGS)
+/*
+ * Calculates union of two boxes, a and b. The result is stored in *n.
+ */
+static void
+rt_box_union(BOX *n, BOX *a, BOX *b)
 {
-   BOX        *a = PG_GETARG_BOX_P(0);
-   BOX        *b = PG_GETARG_BOX_P(1);
-   BOX        *n;
-
-   n = (BOX *) palloc(sizeof(BOX));
-
    n->high.x = Max(a->high.x, b->high.x);
    n->high.y = Max(a->high.y, b->high.y);
    n->low.x = Min(a->low.x, b->low.x);
    n->low.y = Min(a->low.y, b->low.y);
-
-   PG_RETURN_BOX_P(n);
 }
 
 /*
@@ -166,10 +161,12 @@ gist_box_penalty(PG_FUNCTION_ARGS)
    GISTENTRY  *origentry = (GISTENTRY *) PG_GETARG_POINTER(0);
    GISTENTRY  *newentry = (GISTENTRY *) PG_GETARG_POINTER(1);
    float      *result = (float *) PG_GETARG_POINTER(2);
-   Datum       ud;
+   BOX        *origbox = DatumGetBoxP(origentry->key);
+   BOX        *newbox = DatumGetBoxP(newentry->key);
+   BOX         unionbox;
 
-   ud = DirectFunctionCall2(rt_box_union, origentry->key, newentry->key);
-   *result = (float) (size_box(ud) - size_box(origentry->key));
+   rt_box_union(&unionbox, origbox, newbox);
+   *result = (float) (size_box(&unionbox) - size_box(origbox));
    PG_RETURN_POINTER(result);
 }
 
@@ -937,11 +934,9 @@ gist_box_leaf_consistent(BOX *key, BOX *query, StrategyNumber strategy)
 }
 
 static double
-size_box(Datum dbox)
+size_box(BOX *box)
 {
-   BOX        *box = DatumGetBoxP(dbox);
-
-   if (box == NULL || box->high.x <= box->low.x || box->high.y <= box->low.y)
+   if (box->high.x <= box->low.x || box->high.y <= box->low.y)
        return 0.0;
    return (box->high.x - box->low.x) * (box->high.y - box->low.y);
 }