Changeset: 53c1c6dd7704 for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=53c1c6dd7704
Modified Files:
gdk/gdk_select.c
Branch: leftmart
Log Message:
A bitvector-based sort function designed for unsorted cand lists.
Unsorted cand lists are produced during an ordered index selection or a hash
index selection. Instead of trying to sort this list of candidates with the
usual n*log(n) GDKqsort method, we instead set the bits of a bitvector that
correspond to the positions of candidates in the original BAT. We then
sequentially materialize the bitvector to a cand list that it is ordered by
construction, resulting in a 2*n "sort" method.
diffs (83 lines):
diff --git a/gdk/gdk_select.c b/gdk/gdk_select.c
--- a/gdk/gdk_select.c
+++ b/gdk/gdk_select.c
@@ -149,6 +149,56 @@ doubleslice(BAT *b, BUN l1, BUN h1, BUN
return virtualize(bn);
}
+static BAT *
+sort_cand(BAT *b, BUN cnt)
+{
+ BAT *bn;
+ const oid *restrict o;
+ oid *restrict p;
+ unsigned char *bitvector;
+ BUN i,sz_b;
+
+#define remainder8(X) ((X) & 7)
+#define quotient8(X) ((X) >> 3)
+
+ assert(b->ttype=TYPE_oid);
+ /* input must be a potential candidate list or NULL */
+ assert(b == NULL ||
+ (((b->ttype == TYPE_void && b->tseqbase != oid_nil) ||
+ b->ttype == TYPE_oid) &&
+ b->tkey));
+
+ sz_b = BATcount(b);
+ bitvector = (unsigned char *) GDKzalloc(cnt/8+1);
+ if (bitvector == NULL) {
+ GDKerror("#BATbloom: memory allocation error");
+ return GDK_FAIL;
+ }
+
+ o = (oid *) Tloc(b,0);
+ for (i=0; i < sz_b; i++) {
+ bitvector[quotient8(o[i])] |= (1<<remainder8(o[i]));
+ }
+
+ bn = COLnew(0, TYPE_oid, sz_b, TRANSIENT);
+ p = (oid *) Tloc(bn, 0);
+
+ for (i=0; i < cnt; i++) {
+ if (bitvector[quotient8(i)] & (1<<remainder8(i))) {
+ *p = (oid) i;
+ p++;
+ }
+ }
+
+ bn->tsorted = 1;
+ bn->trevsorted = bn->batCount <= 1;
+ bn->tkey = 1;
+ bn->tseqbase = (bn->tdense = bn->batCount <= 1) != 0 ? 0 : oid_nil;
+ bn->tnil = 0;
+ bn->tnonil = 1;
+ return virtualize(bn);
+}
+
#define HASHloop_bound(bi, h, hb, v, lo, hi) \
for (hb = HASHget(h, HASHprobe((h), v)); \
hb != HASHnil(h); \
@@ -1678,16 +1728,18 @@ BATselect(BAT *b, BAT *s, const void *tl
rs++;
}
BATsetcount(bn, cnt);
+ bn->tkey = 1;
+ bn->tnil = 0;
+ bn->tnonil = 1;
}
/* output must be sorted */
+ /*
GDKqsort((oid *) Tloc(bn, 0), NULL, NULL,
(size_t) bn->batCount, sizeof(oid), 0, TYPE_oid);
bn->tsorted = 1;
bn->trevsorted = bn->batCount <= 1;
- bn->tkey = 1;
- bn->tseqbase = (bn->tdense = bn->batCount <= 1)
!= 0 ? 0 : oid_nil;
- bn->tnil = 0;
- bn->tnonil = 1;
+ bn->tseqbase = (bn->tdense = bn->batCount <= 1)
!= 0 ? 0 : oid_nil;*/
+ sort_cand(bn,BATcount(b));
} else {
/* match: [low..high) */
if (s) {
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