Changeset: 116063d25b30 for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=116063d25b30
Modified Files:
gdk/gdk_select.c
Branch: default
Log Message:
More aggressive check for using hash-based select.
Actually look for existing but not yet loaded hash on both the bat
itself and its parent (if it is a view).
diffs (57 lines):
diff --git a/gdk/gdk_select.c b/gdk/gdk_select.c
--- a/gdk/gdk_select.c
+++ b/gdk/gdk_select.c
@@ -1485,15 +1485,28 @@ BATsubselect(BAT *b, BAT *s, const void
}
/* refine upper limit by exact size (if known) */
maximum = MIN(maximum, estimate);
+ parent = VIEWtparent(b);
+ /* use hash only for equi-join, and then only if b or its
+ * parent already has a hash, or if b or its parent is
+ * persistent and the total size wouldn't be too large; check
+ * for existence of hash last since that may involve I/O */
hash = equi &&
- (b->batPersistence == PERSISTENT ||
- ((parent = VIEWtparent(b)) != 0 &&
- BBPquickdesc(abs(parent),0)->batPersistence == PERSISTENT)) &&
- (size_t) ATOMsize(b->ttype) >= sizeof(BUN) / 4 &&
- BATcount(b) * (ATOMsize(b->ttype) + 2 * sizeof(BUN)) <
GDK_mem_maxsize / 2;
- if (hash && estimate == BUN_NONE && !BATcheckhash(b)) {
+ (((b->batPersistence == PERSISTENT ||
+ (parent != 0 &&
+ BBPquickdesc(abs(parent),0)->batPersistence == PERSISTENT))
&&
+ (size_t) ATOMsize(b->ttype) >= sizeof(BUN) / 4 &&
+ BATcount(b) * (ATOMsize(b->ttype) + 2 * sizeof(BUN)) <
GDK_mem_maxsize / 2) ||
+ (BATcheckhash(b) ||
+ (parent != 0 &&
+ BATcheckhash(BBPdescriptor(-parent)))));
+ if (hash &&
+ estimate == BUN_NONE &&
+ !BATcheckhash(b) &&
+ (parent == 0 || !BATcheckhash(BBPdescriptor(-parent)))) {
/* no exact result size, but we need estimate to choose
- * between hash- & scan-select */
+ * between hash- & scan-select
+ * (if we already have a hash, it's a no-brainer: we
+ * use it) */
BUN cnt = BATcount(b);
if (s && BATcount(s) < cnt)
cnt = BATcount(s);
@@ -1546,7 +1559,7 @@ BATsubselect(BAT *b, BAT *s, const void
if (bn == NULL)
return NULL;
- if (equi && (b->T->hash || hash)) {
+ if (equi && hash) {
ALGODEBUG fprintf(stderr, "#BATsubselect(b=%s#" BUNFMT
",s=%s%s,anti=%d): hash select\n",
BATgetId(b), BATcount(b),
@@ -1558,7 +1571,7 @@ BATsubselect(BAT *b, BAT *s, const void
if (!equi &&
!b->tvarsized &&
(b->batPersistence == PERSISTENT ||
- ((parent = VIEWtparent(b)) != 0 &&
+ (parent != 0 &&
BBPquickdesc(abs(parent),0)->batPersistence ==
PERSISTENT))) {
/* use imprints if
* i) bat is persistent, or parent is persistent
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