Changeset: a376ea7469e7 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=a376ea7469e7
Modified Files:
gdk/gdk_batop.c
Branch: Nov2019
Log Message:
Fix race condition during order index creation in BATsort.
(grafted from 88a501afbec3b1a8e5fd4e0a468c9606f9d4bff0)
diffs (93 lines):
diff --git a/gdk/gdk_batop.c b/gdk/gdk_batop.c
--- a/gdk/gdk_batop.c
+++ b/gdk/gdk_batop.c
@@ -1398,6 +1398,7 @@ BATsort(BAT **sorted, BAT **order, BAT *
oid *restrict grps, *restrict ords, prev;
BUN p, q, r;
lng t0 = 0;
+ bool mkorderidx, orderidxlock = false;
ALGODEBUG t0 = GDKusec();
@@ -1429,7 +1430,7 @@ BATsort(BAT **sorted, BAT **order, BAT *
b->trevsorted = !b->trevsorted;
b->batDirtydesc = true;
}
- if (b->tkey != BATtdense(b)) {
+ if (b->tkey != !is_oid_nil(b->tseqbase)) {
b->tkey = !b->tkey;
b->batDirtydesc = true;
}
@@ -1535,8 +1536,26 @@ BATsort(BAT **sorted, BAT **order, BAT *
} else {
pb = b;
}
+ /* when we will create an order index if it doesn't already exist */
+ mkorderidx = (g == NULL && !reverse && !nilslast && pb != NULL &&
(order || !pb->batTransient));
+ if (g == NULL && !reverse && !nilslast &&
+ pb != NULL && !BATcheckorderidx(pb)) {
+ MT_lock_set(&GDKhashLock(pb->batCacheid));
+ if (pb->torderidx == NULL) {
+ /* no index created while waiting for lock */
+ if (mkorderidx) /* keep lock when going to create */
+ orderidxlock = true;
+ } else {
+ /* no need to create an index: it already exists */
+ mkorderidx = false;
+ }
+ if (!orderidxlock)
+ MT_lock_unset(&GDKhashLock(pb->batCacheid));
+ } else {
+ mkorderidx = false;
+ }
if (g == NULL && o == NULL && !reverse && !nilslast &&
- pb != NULL && BATcheckorderidx(pb) &&
+ pb != NULL && pb->torderidx != NULL &&
/* if we want a stable sort, the order index must be
* stable, if we don't want stable, we don't care */
(!stable || ((oid *) pb->torderidx->base)[2])) {
@@ -1730,12 +1749,10 @@ BATsort(BAT **sorted, BAT **order, BAT *
Heap *m = NULL;
/* only invest in creating an order index if the BAT
* is persistent */
- if (!reverse &&
- !nilslast &&
- pb != NULL &&
- (ords != NULL || !pb->batTransient) &&
- (m = createOIDXheap(pb, stable)) != NULL) {
- if (ords == NULL) {
+ if (mkorderidx) {
+ assert(orderidxlock);
+ if ((m = createOIDXheap(pb, stable)) != NULL &&
+ ords == NULL) {
ords = (oid *) m->base + ORDERIDXOFF;
if (o && o->ttype != TYPE_void)
memcpy(ords, Tloc(o, 0), BATcount(o) *
sizeof(oid));
@@ -1759,12 +1776,14 @@ BATsort(BAT **sorted, BAT **order, BAT *
HEAPfree(m, true);
GDKfree(m);
}
+ if (orderidxlock)
+ MT_lock_unset(&GDKhashLock(pb->batCacheid));
goto error;
}
bn->tsorted = !reverse && !nilslast;
bn->trevsorted = reverse && nilslast;
if (m != NULL) {
- MT_lock_set(&GDKhashLock(pb->batCacheid));
+ assert(orderidxlock);
if (pb->torderidx == NULL) {
pb->batDirtydesc = true;
if (ords != (oid *) m->base + ORDERIDXOFF) {
@@ -1778,9 +1797,10 @@ BATsort(BAT **sorted, BAT **order, BAT *
HEAPfree(m, true);
GDKfree(m);
}
- MT_lock_unset(&GDKhashLock(pb->batCacheid));
}
}
+ if (orderidxlock)
+ MT_lock_unset(&GDKhashLock(pb->batCacheid));
bn->theap.dirty = true;
bn->tnosorted = 0;
bn->tnorevsorted = 0;
_______________________________________________
checkin-list mailing list
checkin-list@monetdb.org
https://www.monetdb.org/mailman/listinfo/checkin-list
