Changeset: 0ffddbf066db for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=0ffddbf066db
Modified Files:
gdk/gdk_hash.c
Branch: linear-hashing
Log Message:
Keep hash table 7/8 full.
diffs (39 lines):
diff --git a/gdk/gdk_hash.c b/gdk/gdk_hash.c
--- a/gdk/gdk_hash.c
+++ b/gdk/gdk_hash.c
@@ -54,6 +54,7 @@ HASHmask(BUN cnt)
{
BUN m = cnt;
+#if 0
/* find largest power of 2 smaller than or equal to cnt */
m |= m >> 1;
m |= m >> 2;
@@ -69,6 +70,9 @@ HASHmask(BUN cnt)
double m */
if (m + m - cnt < 2 * (cnt - m))
m += m;
+#else
+ m = m * 8 / 7;
+#endif
if (m < BATTINY)
m = BATTINY;
return m;
@@ -327,7 +331,7 @@ HASHgrowbucket(BAT *b)
MT_msync(h->heapbckt.base, SIZEOF_SIZE_T);
}
}
- while (h->nunique >= (nbucket = NHASHBUCKETS(h)) * 3 / 4) {
+ while (h->nunique >= (nbucket = NHASHBUCKETS(h)) * 7 / 8) {
BUN old = h->split;
BUN new = ((BUN) 1 << h->level) + h->split;
BATiter bi = bat_iterator(b);
@@ -721,7 +725,7 @@ BAThash_impl(BAT *b, BAT *s, const char
mask = HASHmask(cnt);
} else if (s == NULL && (prop = BATgetprop_nolock(b, GDK_NUNIQUE)) !=
NULL) {
assert(prop->v.vtype == TYPE_oid);
- mask = prop->v.val.oval * 4 / 3;
+ mask = prop->v.val.oval * 8 / 7;
} else if (s == NULL && (prop = BATgetprop_nolock(b, GDK_HASH_BUCKETS))
!= NULL) {
assert(prop->v.vtype == TYPE_oid);
mask = prop->v.val.oval;
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