Changeset: 6cfed0167e2e for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=6cfed0167e2e
Modified Files:
gdk/gdk_batop.c
Branch: Feb2013
Log Message:
Added another shortcut in BATsubsort.
If the input is already sorted and we need to return group
information, we can take a shortcut if the input is also key or
constant.
This should fix bug 3368.
diffs (46 lines):
diff --git a/gdk/gdk_batop.c b/gdk/gdk_batop.c
--- a/gdk/gdk_batop.c
+++ b/gdk/gdk_batop.c
@@ -1297,8 +1297,12 @@ BATsubsort(BAT **sorted, BAT **order, BA
/* no place to put result, so we're done quickly */
return GDK_SUCCEED;
}
- if (BATcount(b) <= 1 || (BATtordered(b) && o == NULL && g == NULL &&
groups == NULL)) {
- /* trivially (sub)sorted */
+ if (BATcount(b) <= 1 ||
+ (BATtordered(b) && o == NULL && g == NULL &&
+ (groups == NULL || BATtkey(b) || BATtrevordered(b)))) {
+ /* trivially (sub)sorted, and either we don't need to
+ * return group information, or we can trivially
+ * deduce the groups */
if (sorted) {
BBPfix(b->batCacheid);
bn = b;
@@ -1314,12 +1318,22 @@ BATsubsort(BAT **sorted, BAT **order, BA
*order = on;
}
if (groups) {
- gn = BATnew(TYPE_void, TYPE_void, BATcount(b));
- if (gn == NULL)
- goto error;
- BATsetcount(gn, BATcount(b));
+ if (BATtkey(b)) {
+ /* singleton groups */
+ gn = BATnew(TYPE_void, TYPE_void, BATcount(b));
+ if (gn == NULL)
+ goto error;
+ BATsetcount(gn, BATcount(b));
+ BATseqbase(BATmirror(gn), 0);
+ } else {
+ /* single group */
+ const oid *o = 0;
+ assert(BATcount(b) == 1 || BATtrevordered(b));
+ gn = BATconstant(TYPE_oid, &o, BATcount(b));
+ if (gn == NULL)
+ goto error;
+ }
BATseqbase(gn, 0);
- BATseqbase(BATmirror(gn), 0);
*groups = gn;
}
return GDK_SUCCEED;
_______________________________________________
checkin-list mailing list
[email protected]
https://www.monetdb.org/mailman/listinfo/checkin-list
