Update of /cvsroot/monetdb/pathfinder/compiler/algebra
In directory 23jxhf1.ch3.sourceforge.com:/tmp/cvs-serv2665/algebra
Modified Files:
Tag: Nov2009
planner.c
Log Message:
-- Restrict heuristic to avoid blowing up the plan size (even more).
-- Take functional dependencies for distinct planning into account.
Index: planner.c
===================================================================
RCS file: /cvsroot/monetdb/pathfinder/compiler/algebra/planner.c,v
retrieving revision 1.87.2.2
retrieving revision 1.87.2.3
diff -u -d -r1.87.2.2 -r1.87.2.3
--- planner.c 18 Nov 2009 09:11:09 -0000 1.87.2.2
+++ planner.c 18 Nov 2009 15:56:55 -0000 1.87.2.3
@@ -124,6 +124,8 @@
/* Easily access subtree-parts */
#include "child_mnemonic.h"
+#define MAGIC_BOUNDARY 5000
+
/**
* A ``plan'' is actually a physical algebra operator tree.
*/
@@ -1372,6 +1374,19 @@
}
/**
+ * Check if a column functionally depends on any other column
+ * in the schema. */
+static bool
+dependent_col (const PFla_op_t *n, PFalg_col_t dependent)
+{
+ for (unsigned int i = 0; i < n->schema.count; i++)
+ if (n->schema.items[i].name != dependent &&
+ PFprop_fd (n->prop, n->schema.items[i].name, dependent))
+ return true;
+ return false;
+}
+
+/**
* Create physical plan for Distinct operator (duplicate elimination).
*
* AFAIK, MonetDB only can do SortDistinct, i.e., sort its input, then
@@ -1389,7 +1404,8 @@
PFplanlist_t *sorted;
for (unsigned int i = 0; i < n->schema.count; i++)
- if (!PFprop_const (n->prop, n->schema.items[i].name))
+ if (!PFprop_const (n->prop, n->schema.items[i].name) &&
+ !dependent_col (n, n->schema.items[i].name))
ord = PFord_refine (ord,
n->schema.items[i].name,
DIR_ASC /* will be ignored anyway */);
@@ -1418,6 +1434,8 @@
add_plan (ret,
sort_distinct (*(plan_t **) PFarray_at (sorted, i),
PFord_set_at (perms, p)));
+ if (PFarray_last (ret) > MAGIC_BOUNDARY)
+ break;
}
return ret;
@@ -3980,7 +3998,7 @@
Furthermore ensure that we do not increase the plan space
if we already have a large number of possible plans. */
if (PFord_set_count (p->orderings) < 1000 &&
- PFarray_last (plans) < 5000)
+ PFarray_last (plans) < MAGIC_BOUNDARY)
for (i = 0; i < PFord_set_count (orderings); i++) {
ord = PFord_set_at (orderings, i);
add_plans (plans, ensure_ordering (p, ord));
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