Changeset: 773a53092cf6 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=773a53092cf6
Modified Files:
gdk/gdk_join.c
Branch: pushdown
Log Message:
Improved some cost calculations.
diffs (165 lines):
diff --git a/gdk/gdk_join.c b/gdk/gdk_join.c
--- a/gdk/gdk_join.c
+++ b/gdk/gdk_join.c
@@ -3533,7 +3533,7 @@ leftjoin(BAT **r1p, BAT **r2p, BAT *l, B
/* no hash table, so cost includes time to build the
* hash table (single scan) plus the time to do the
* lookups (also single scan, we assume some chains) */
- rcost = (double) rci.ncand + lci.ncand * 1.1;
+ rcost = (double) rci.ncand * 2 + lci.ncand * 1.1;
} else {
if (rci.noids > 0) {
/* if we need to do binary search on candidate
@@ -3544,17 +3544,17 @@ leftjoin(BAT **r1p, BAT **r2p, BAT *l, B
* rci.ncand */
rcost *= lci.ncand;
if (rci.ncand < BATcount(r) &&
- rci.ncand + lci.ncand * 1.1 < rcost) {
+ rci.ncand * 2 + lci.ncand * 1.1 < rcost) {
/* it's cheaper to rebuild the hash table for
* just the candidates (this saves on the
* binary searches), again, assume some
* chains */
rhash = prhash = false;
- rcost = rci.ncand + lci.ncand * 1.1;
+ rcost = rci.ncand * 2 + lci.ncand * 1.1;
}
}
- if (!nil_on_miss && !only_misses && !not_in && r2p == NULL) {
+ if (!nil_on_miss && !only_misses && !not_in) {
/* maybe do a hash join on the swapped operands; if we
* do, we need to sort the output, so we take that into
* account as well */
@@ -3576,7 +3576,7 @@ leftjoin(BAT **r1p, BAT **r2p, BAT *l, B
/* no hash table, so cost includes time to build the
* hash table (single scan) plus the time to do the
* lookups (also single scan, we assume some chains) */
- lcost = (double) lci.ncand + rci.ncand * 1.1;
+ lcost = (double) lci.ncand * 2 + rci.ncand * 1.1;
} else {
if (lci.noids > 0) {
/* if we need to do binary search on candidate
@@ -3587,13 +3587,13 @@ leftjoin(BAT **r1p, BAT **r2p, BAT *l, B
* rci.ncand */
lcost *= rci.ncand;
if (lci.ncand < BATcount(l) &&
- lci.ncand + rci.ncand * 1.1 < lcost) {
+ lci.ncand * 2 + rci.ncand * 1.1 < lcost) {
/* it's cheaper to rebuild the hash table for
* just the candidates (this saves on the
* binary searches), again, assume some
* chains */
lhash = plhash = false;
- lcost = lci.ncand + rci.ncand * 1.1;
+ lcost = lci.ncand * 2 + rci.ncand * 1.1;
}
}
if (semi)
@@ -3614,12 +3614,12 @@ leftjoin(BAT **r1p, BAT **r2p, BAT *l, B
rc = hashjoin(&r2, &r1, r, l, &rci, &lci, nil_matches,
false, false, false, false, estimate,
t0, true, lhash, plhash, func);
- if (semi) {
+ if (semi)
BBPunfix(sr->batCacheid);
- r1->tkey = true;
- }
if (rc != GDK_SUCCEED)
return rc;
+ if (semi)
+ r1->tkey = true;
BAT *ob;
rc = BATsort(&tmp, r2p ? &ob : NULL, NULL,
r1, NULL, NULL, false, false, false);
@@ -3629,7 +3629,6 @@ leftjoin(BAT **r1p, BAT **r2p, BAT *l, B
return rc;
}
*r1p = r1 = tmp;
-#if 0
if (r2p) {
tmp = BATproject(ob, r2);
BBPunfix(r2->batCacheid);
@@ -3640,7 +3639,8 @@ leftjoin(BAT **r1p, BAT **r2p, BAT *l, B
}
*r2p = tmp;
}
-#endif
+#if 0
+#ifndef NDEBUG
BAT *x1;
canditer_reset(&lci);
canditer_reset(&rci);
@@ -3649,6 +3649,8 @@ leftjoin(BAT **r1p, BAT **r2p, BAT *l, B
for (BUN x = 0; x < x1->batCount; x++)
assert(BUNtoid(r1, x) == BUNtoid(x1, x));
BBPunfix(x1->batCacheid);
+#endif
+#endif
return GDK_SUCCEED;
}
}
@@ -3866,7 +3868,9 @@ BATjoin(BAT **r1p, BAT **r2p, BAT *l, BA
/* no hash table, so cost includes time to build the
* hash table (single scan) plus the time to do the
* lookups (also single scan, we assume some chains) */
- lcost = (double) lci.ncand + rci.ncand * 1.1;
+ lcost = (double) lci.ncand * 2 + rci.ncand * 1.1;
+ if (lci.ncand == BATcount(l) && !l->batTransient)
+ lcost *= 0.8;
} else {
if (lci.noids > 0) {
/* if we need to do binary search on candidate
@@ -3877,13 +3881,15 @@ BATjoin(BAT **r1p, BAT **r2p, BAT *l, BA
* rci.ncand */
lcost *= rci.ncand;
if (lci.ncand < BATcount(l) &&
- lci.ncand + rci.ncand * 1.1 < lcost) {
+ lci.noids > 0 &&
+ lci.ncand * 2 + rci.ncand * 1.1 < lcost) {
/* it's cheaper to rebuild the hash table for
* just the candidates (this saves on the
* binary searches), again, assume some
* chains */
lhash = plhash = false;
lcost = lci.ncand + rci.ncand * 1.1;
+ lcost *= 2;
}
}
rhash = BATcheckhash(r);
@@ -3903,7 +3909,9 @@ BATjoin(BAT **r1p, BAT **r2p, BAT *l, BA
/* no hash table, so cost includes time to build the
* hash table (single scan) plus the time to do the
* lookups (also single scan, we assume some chains) */
- rcost = (double) rci.ncand + lci.ncand * 1.1;
+ rcost = (double) rci.ncand * 2 + lci.ncand * 1.1;
+ if (rci.ncand == BATcount(r) && !r->batTransient)
+ rcost *= 0.8;
} else {
if (rci.noids > 0) {
/* if we need to do binary search on candidate
@@ -3914,20 +3922,22 @@ BATjoin(BAT **r1p, BAT **r2p, BAT *l, BA
* rci.ncand */
rcost *= lci.ncand;
if (rci.ncand < BATcount(r) &&
- rci.ncand + lci.ncand * 1.1 < rcost) {
+ rci.noids > 0 &&
+ 2 * (rci.ncand + lci.ncand * 1.1) < rcost) {
/* it's cheaper to rebuild the hash table for
* just the candidates (this saves on the
* binary searches), again, assume some
* chains */
rhash = prhash = false;
rcost = rci.ncand + lci.ncand * 1.1;
+ rcost *= 2;
}
}
/* if the cost of doing searches on l is lower than the cost
* to do searches on r, we swap (i.e., lookups on right), but
* add a cost */
- swap = (1.2 * lcost < rcost);
+ swap = (lcost < rcost);
if ((BATordered(r) || BATordered_rev(r)) &&
(lci.ncand * (log2(rci.ncand) + 1) < (swap ? lcost : rcost))) {
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