Changeset: 1a0ab345fe4f for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=1a0ab345fe4f
Modified Files:
gdk/gdk_orderidx.c
Branch: Dec2016
Log Message:
Move unfix to outside the lock: it may cause deadlock (see comment).
diffs (43 lines):
diff --git a/gdk/gdk_orderidx.c b/gdk/gdk_orderidx.c
--- a/gdk/gdk_orderidx.c
+++ b/gdk/gdk_orderidx.c
@@ -121,6 +121,7 @@ BATorderidx(BAT *b, int stable)
const char *nme;
oid seq;
BUN p, q;
+ BAT *bn = NULL;
if (BATcheckorderidx(b))
return GDK_SUCCEED;
@@ -155,7 +156,7 @@ BATorderidx(BAT *b, int stable)
if (!BATtdense(b)) {
/* we need to sort a copy of the column so as not to
* change the original */
- BAT *bn = COLcopy(b, b->ttype, TRUE, TRANSIENT);
+ bn = COLcopy(b, b->ttype, TRUE, TRANSIENT);
if (bn == NULL) {
HEAPfree(m, 1);
GDKfree(m);
@@ -179,7 +180,11 @@ BATorderidx(BAT *b, int stable)
BATcount(bn), Tsize(bn), SIZEOF_OID,
bn->ttype);
}
- BBPunfix(bn->batCacheid);
+ /* we must unfix after releasing the lock since we
+ * might get deadlock otherwise (we're holding a lock
+ * based on b->batCacheid; unfix tries to get a lock
+ * based on bn->batCacheid, usually but (crucially)
+ * not always a different lock) */
}
#ifdef PERSISTENTIDX
@@ -202,6 +207,9 @@ BATorderidx(BAT *b, int stable)
b->torderidx = m;
MT_lock_unset(&GDKhashLock(b->batCacheid));
+ if (bn)
+ BBPunfix(bn->batCacheid);
+
return GDK_SUCCEED;
}
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