Update of /cvsroot/monetdb/pathfinder/compiler/algebra/opt
In directory 23jxhf1.ch3.sourceforge.com:/tmp/cvs-serv8656/algebra/opt
Modified Files:
opt_general.brg
Log Message:
-- Added optimization that removes superfluous aggregates.
U opt_general.brg
Index: opt_general.brg
===================================================================
RCS file: /cvsroot/monetdb/pathfinder/compiler/algebra/opt/opt_general.brg,v
retrieving revision 1.70
retrieving revision 1.71
diff -u -d -r1.70 -r1.71
--- opt_general.brg 5 Oct 2009 09:35:56 -0000 1.70
+++ opt_general.brg 5 Oct 2009 13:29:14 -0000 1.71
@@ -1045,7 +1045,11 @@
/* Rel: aggr (Rel) */
case 45:
{
- unsigned int i = 0;
+ unsigned int i,
+ count;
+ bool rewrite = false;
+ PFalg_proj_t *proj;
+
for (i = 0; i < p->sem.aggr.count; i++)
if (p->sem.aggr.aggr[i].kind != alg_aggr_dist)
break;
@@ -1067,6 +1071,56 @@
relabel (p, kids);
break;
}
+
+ /* Get rid of superfluos aggregates that operate on the grouping
+ column. Add the missing columns by a projection on top of the
+ aggregate. */
+ proj = PFmalloc (p->schema.count * sizeof (PFalg_proj_t));
+ count = 0;
+ i = 0;
+
+ /* get rid of superfluous aggregates */
+ while (i < p->sem.aggr.count) {
+ if ((p->sem.aggr.aggr[i].kind == alg_aggr_dist ||
+ p->sem.aggr.aggr[i].kind == alg_aggr_min ||
+ p->sem.aggr.aggr[i].kind == alg_aggr_max) &&
+ p->sem.aggr.aggr[i].col == p->sem.aggr.part) {
+ proj[count++] = PFalg_proj (p->sem.aggr.aggr[i].res,
+ p->sem.aggr.part);
+ p->sem.aggr.count--;
+ p->sem.aggr.aggr[i] = p->sem.aggr.aggr[p->sem.aggr.count];
+ rewrite = true;
+ }
+ else {
+ proj[count++] = PFalg_proj (p->sem.aggr.aggr[i].res,
+ p->sem.aggr.aggr[i].res);
+ i++;
+ }
+ }
+ /* complete projection list by adding grouping column */
+ proj[count++] = PFalg_proj (p->sem.aggr.part, p->sem.aggr.part);
+
+ if (rewrite) {
+ *p = *PFla_project_ (
+ p->sem.aggr.count
+ ? PFla_aggr (
+ L(p),
+ p->sem.aggr.part,
+ p->sem.aggr.count,
+ p->sem.aggr.aggr)
+ /* skip aggregate if only the grouping
+ column is needed */
+ : PFla_distinct (
+ PFla_project (
+ L(p),
+ PFalg_proj (p->sem.aggr.part,
+ p->sem.aggr.part))),
+ count,
+ proj);
+ SEEN(p) = false;
+ relabel (p, kids);
+ }
+
} break;
/* Rel: rownum (Rel) */
------------------------------------------------------------------------------
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