diff --git a/CHANGES b/CHANGES
index af1a85a5a9..3a4fe31a5f 100644
--- a/CHANGES
+++ b/CHANGES
@@ -17,9 +17,10 @@
 1581.	[func]		Disable DNSSEC support by default.  To enable
 			DNSSEC specify "enable-dnssec yes;" in named.conf.
 
-1580.	[placeholder]	rt3746a
+1580.	[bug]		Zone destuction on final detach takes a long time.
+			[RT #3746]
 
-1579.	[placeholder]	rt3746a
+1579.	[bug]		Multiple task managers could not be created.
 
 1578.	[bug]		Don't use CLASS E IPv4 addresses when resolving.
 			[RT #10346]
diff --git a/lib/dns/db.c b/lib/dns/db.c
index c1203c6d84..8814dd710f 100644
--- a/lib/dns/db.c
+++ b/lib/dns/db.c
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: db.c,v 1.72 2003/10/03 03:12:35 marka Exp $ */
+/* $Id: db.c,v 1.73 2004/03/04 06:56:38 marka Exp $ */
 
 /***
  *** Imports
@@ -730,6 +730,13 @@ dns_db_nodecount(dns_db_t *db) {
 	return ((db->methods->nodecount)(db));
 }
 
+void
+dns_db_settask(dns_db_t *db, isc_task_t *task) {
+	REQUIRE(DNS_DB_VALID(db));
+
+	(db->methods->settask)(db, task);
+}
+
 isc_result_t
 dns_db_register(const char *name, dns_dbcreatefunc_t create, void *driverarg,
 		isc_mem_t *mctx, dns_dbimplementation_t **dbimp)
diff --git a/lib/dns/include/dns/db.h b/lib/dns/include/dns/db.h
index 975e2a0031..04ef341f78 100644
--- a/lib/dns/include/dns/db.h
+++ b/lib/dns/include/dns/db.h
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: db.h,v 1.74 2003/10/03 03:12:35 marka Exp $ */
+/* $Id: db.h,v 1.75 2004/03/04 06:56:40 marka Exp $ */
 
 #ifndef DNS_DB_H
 #define DNS_DB_H 1
@@ -144,6 +144,7 @@ typedef struct dns_dbmethods {
 	unsigned int	(*nodecount)(dns_db_t *db);
 	isc_boolean_t	(*ispersistent)(dns_db_t *db);
 	void		(*overmem)(dns_db_t *db, isc_boolean_t overmem);
+	void		(*settask)(dns_db_t *db, isc_task_t *);
 } dns_dbmethods_t;
 
 typedef isc_result_t
@@ -1189,6 +1190,16 @@ dns_db_nodecount(dns_db_t *db);
  * 	The number of nodes in the database
  */
 
+void
+dns_db_settask(dns_db_t *db, isc_task_t *task);
+/*
+ * If task is set then the final detach maybe performed asynchronously.
+ *
+ * Requires:
+ *	'db' is a valid database.
+ *	'task' to be valid or NULL.
+ */
+
 isc_boolean_t
 dns_db_ispersistent(dns_db_t *db);
 /*
diff --git a/lib/dns/include/dns/events.h b/lib/dns/include/dns/events.h
index d44dbd2f45..b048f2697d 100644
--- a/lib/dns/include/dns/events.h
+++ b/lib/dns/include/dns/events.h
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: events.h,v 1.40 2002/09/04 02:26:13 jinmei Exp $ */
+/* $Id: events.h,v 1.41 2004/03/04 06:56:40 marka Exp $ */
 
 #ifndef DNS_EVENTS_H
 #define DNS_EVENTS_H 1
@@ -62,6 +62,7 @@
 #define DNS_EVENT_REQUESTCONTROL		(ISC_EVENTCLASS_DNS + 33)
 #define DNS_EVENT_DUMPQUANTUM			(ISC_EVENTCLASS_DNS + 34)
 #define DNS_EVENT_IMPORTRECVDONE		(ISC_EVENTCLASS_DNS + 35)
+#define DNS_EVENT_FREESTORAGE			(ISC_EVENTCLASS_DNS + 36)
 
 #define DNS_EVENT_FIRSTEVENT			(ISC_EVENTCLASS_DNS + 0)
 #define DNS_EVENT_LASTEVENT			(ISC_EVENTCLASS_DNS + 65535)
diff --git a/lib/dns/include/dns/rbt.h b/lib/dns/include/dns/rbt.h
index 0d49eaa6e1..d82586f40b 100644
--- a/lib/dns/include/dns/rbt.h
+++ b/lib/dns/include/dns/rbt.h
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: rbt.h,v 1.57 2002/12/31 05:40:15 marka Exp $ */
+/* $Id: rbt.h,v 1.58 2004/03/04 06:56:40 marka Exp $ */
 
 #ifndef DNS_RBT_H
 #define DNS_RBT_H 1
@@ -600,8 +600,13 @@ dns_rbt_nodecount(dns_rbt_t *rbt);
 
 void
 dns_rbt_destroy(dns_rbt_t **rbtp);
+isc_result_t
+dns_rbt_destroy2(dns_rbt_t **rbtp, unsigned int quantum);
 /*
- * Stop working with a red-black tree of trees.
+ * Stop working with a red-black tree of trees.  Once dns_rbt_destroy2()
+ * has been called on a 'rbt' only dns_rbt_destroy() or dns_rbt_destroy2()
+ * may be used on the tree.  If 'quantum' is zero then the entire tree will
+ * be destroyed.
  *
  * Requires:
  * 	*rbt is a valid rbt manager.
@@ -610,6 +615,10 @@ dns_rbt_destroy(dns_rbt_t **rbtp);
  *	All space allocated by the RBT library has been returned.
  *
  *	*rbt is invalidated as an rbt manager.
+ *
+ * Returns:
+ *	ISC_R_SUCCESS
+ *	ISC_R_QUOTA if 'quantum' nodes have been destroyed.
  */
 
 void
diff --git a/lib/dns/rbt.c b/lib/dns/rbt.c
index 1094fdf6ee..c557a64200 100644
--- a/lib/dns/rbt.c
+++ b/lib/dns/rbt.c
@@ -15,13 +15,14 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: rbt.c,v 1.126 2004/03/03 22:40:56 marka Exp $ */
+/* $Id: rbt.c,v 1.127 2004/03/04 06:56:39 marka Exp $ */
 
 /* Principal Authors: DCL */
 
 #include <config.h>
 
 #include <isc/mem.h>
+#include <isc/platform.h>
 #include <isc/print.h>
 #include <isc/string.h>
 #include <isc/util.h>
@@ -63,6 +64,7 @@ struct dns_rbt {
 	unsigned int		nodecount;
 	unsigned int		hashsize;
 	dns_rbtnode_t **	hashtable;
+	unsigned int		quantum;
 };
 
 #define RED 0
@@ -225,9 +227,12 @@ dns_rbt_addonlevel(dns_rbtnode_t *node, dns_rbtnode_t *current, int order,
 static void
 dns_rbt_deletefromlevel(dns_rbtnode_t *delete, dns_rbtnode_t **rootp);
 
-static void
+static isc_result_t
 dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node);
 
+static void
+dns_rbt_deletetreeflat(dns_rbt_t *rbt, dns_rbtnode_t **nodep);
+
 /*
  * Initialize a red/black tree of trees.
  */
@@ -263,6 +268,7 @@ dns_rbt_create(isc_mem_t *mctx, void (*deleter)(void *, void *),
 		return (result);
 	}
 #endif
+	rbt->quantum = 0;
 	rbt->magic = RBT_MAGIC;
 
 	*rbtp = rbt;
@@ -275,13 +281,22 @@ dns_rbt_create(isc_mem_t *mctx, void (*deleter)(void *, void *),
  */
 void
 dns_rbt_destroy(dns_rbt_t **rbtp) {
+	RUNTIME_CHECK(dns_rbt_destroy2(rbtp, 0) == ISC_R_SUCCESS);
+}
+
+isc_result_t
+dns_rbt_destroy2(dns_rbt_t **rbtp, unsigned int quantum) {
 	dns_rbt_t *rbt;
 
 	REQUIRE(rbtp != NULL && VALID_RBT(*rbtp));
 
 	rbt = *rbtp;
 
-	dns_rbt_deletetree(rbt, rbt->root);
+	rbt->quantum = quantum;
+
+	dns_rbt_deletetreeflat(rbt, &rbt->root);
+	if (rbt->root != NULL)
+		return (ISC_R_QUOTA);
 
 	INSIST(rbt->nodecount == 0);
 
@@ -292,8 +307,8 @@ dns_rbt_destroy(dns_rbt_t **rbtp) {
 	rbt->magic = 0;
 
 	isc_mem_put(rbt->mctx, rbt, sizeof(*rbt));
-
 	*rbtp = NULL;
+	return (ISC_R_SUCCESS);
 }
 
 unsigned int
@@ -1258,7 +1273,8 @@ dns_rbt_deletenode(dns_rbt_t *rbt, dns_rbtnode_t *node, isc_boolean_t recurse)
 
 	if (DOWN(node) != NULL) {
 		if (recurse)
-			dns_rbt_deletetree(rbt, DOWN(node));
+			RUNTIME_CHECK(dns_rbt_deletetree(rbt, DOWN(node))
+				      == ISC_R_SUCCESS);
 		else {
 			if (DATA(node) != NULL && rbt->data_deleter != NULL)
 				rbt->data_deleter(DATA(node),
@@ -1527,7 +1543,7 @@ hash_node(dns_rbt_t *rbt, dns_rbtnode_t *node) {
 
 	REQUIRE(DNS_RBTNODE_VALID(node));
 
-	if (rbt->nodecount >= rbt->hashsize)
+	if (rbt->nodecount >= (rbt->hashsize *3))
 		rehash(rbt);
 
 	hash_add_node(rbt, node);
@@ -1976,19 +1992,37 @@ dns_rbt_deletefromlevel(dns_rbtnode_t *delete, dns_rbtnode_t **rootp) {
  * a pointer needs to be told that this tree no longer exists,
  * this function would need to adjusted accordingly.
  */
-static void
+static isc_result_t
 dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node) {
+	isc_result_t result = ISC_R_SUCCESS;
 	REQUIRE(VALID_RBT(rbt));
 
 	if (node == NULL)
-		return;
+		return (result);
 
-	if (LEFT(node) != NULL)
-		dns_rbt_deletetree(rbt, LEFT(node));
-	if (RIGHT(node) != NULL)
-		dns_rbt_deletetree(rbt, RIGHT(node));
-	if (DOWN(node) != NULL)
-		dns_rbt_deletetree(rbt, DOWN(node));
+	if (LEFT(node) != NULL) {
+		result = dns_rbt_deletetree(rbt, LEFT(node));
+		if (result != ISC_R_SUCCESS)
+			goto done;
+		LEFT(node) = NULL;
+	}
+	if (RIGHT(node) != NULL) {
+		result = dns_rbt_deletetree(rbt, RIGHT(node));
+		if (result != ISC_R_SUCCESS)
+			goto done;
+		RIGHT(node) = NULL;
+	}
+	if (DOWN(node) != NULL) {
+		result = dns_rbt_deletetree(rbt, DOWN(node));
+		if (result != ISC_R_SUCCESS)
+			goto done;
+		DOWN(node) = NULL;
+	}
+ done:
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	if (rbt->quantum != 0 && --rbt->quantum == 0)
+		return (ISC_R_QUOTA);
 
 	if (DATA(node) != NULL && rbt->data_deleter != NULL)
 		rbt->data_deleter(DATA(node), rbt->deleter_arg);
@@ -1999,6 +2033,59 @@ dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node) {
 #endif
 	isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
 	rbt->nodecount--;
+	return (result);
+}
+
+static void
+dns_rbt_deletetreeflat(dns_rbt_t *rbt, dns_rbtnode_t **nodep) {
+	dns_rbtnode_t *parent;
+	dns_rbtnode_t *node = *nodep;
+	REQUIRE(VALID_RBT(rbt));
+
+ again:
+	if (node == NULL) {
+		*nodep = NULL;
+		return;
+	}
+
+ traverse:
+	if (LEFT(node) != NULL) {
+		node = LEFT(node);
+		goto traverse;
+	}
+	if (RIGHT(node) != NULL) {
+		node = RIGHT(node);
+		goto traverse;
+	}
+	if (DOWN(node) != NULL) {
+		node = DOWN(node);
+		goto traverse;
+	}
+
+	if (DATA(node) != NULL && rbt->data_deleter != NULL)
+		rbt->data_deleter(DATA(node), rbt->deleter_arg);
+
+	unhash_node(rbt, node);
+#if DNS_RBT_USEMAGIC
+	node->magic = 0;
+#endif
+	parent = PARENT(node);
+	if (parent != NULL) {
+		if (LEFT(parent) == node)
+			LEFT(parent) = NULL;
+		else if (DOWN(parent) == node)
+			DOWN(parent) = NULL;
+		else if (RIGHT(parent) == node)
+			RIGHT(parent) = NULL;
+	}
+	isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
+	rbt->nodecount--;
+	node = parent;
+	if (rbt->quantum != 0 && --rbt->quantum == 0) {
+		*nodep = node;
+		return;
+	}
+	goto again;
 }
 
 static void
diff --git a/lib/dns/rbtdb.c b/lib/dns/rbtdb.c
index 9cc1a35d34..9f812741a9 100644
--- a/lib/dns/rbtdb.c
+++ b/lib/dns/rbtdb.c
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: rbtdb.c,v 1.194 2004/03/04 02:46:28 marka Exp $ */
+/* $Id: rbtdb.c,v 1.195 2004/03/04 06:56:39 marka Exp $ */
 
 /*
  * Principal Author: Bob Halley
@@ -23,6 +23,7 @@
 
 #include <config.h>
 
+#include <isc/event.h>
 #include <isc/mem.h>
 #include <isc/print.h>
 #include <isc/mutex.h>
@@ -30,10 +31,12 @@
 #include <isc/refcount.h>
 #include <isc/rwlock.h>
 #include <isc/string.h>
+#include <isc/task.h>
 #include <isc/util.h>
 
 #include <dns/db.h>
 #include <dns/dbiterator.h>
+#include <dns/events.h>
 #include <dns/fixedname.h>
 #include <dns/log.h>
 #include <dns/masterdump.h>
@@ -215,6 +218,7 @@ typedef struct {
 	rbtdb_version_t *		future_version;
 	rbtdb_versionlist_t		open_versions;
 	isc_boolean_t			overmem;
+	isc_task_t *			task;
 	/* Locked by tree_lock. */
 	dns_rbt_t *			tree;
 	isc_boolean_t			secure;
@@ -339,6 +343,9 @@ typedef struct rbtdb_dbiterator {
 #define IS_STUB(rbtdb)  (((rbtdb)->common.attributes & DNS_DBATTR_STUB)  != 0)
 #define IS_CACHE(rbtdb) (((rbtdb)->common.attributes & DNS_DBATTR_CACHE) != 0)
 
+static void free_rbtdb(dns_rbtdb_t *rbtdb, isc_boolean_t log,
+		       isc_event_t *event);
+
 /*
  * Locking
  *
@@ -382,10 +389,20 @@ attach(dns_db_t *source, dns_db_t **targetp) {
 }
 
 static void
-free_rbtdb(dns_rbtdb_t *rbtdb) {
+free_rbtdb_callback(isc_task_t *task, isc_event_t *event) {
+	dns_rbtdb_t *rbtdb = event->ev_arg;
+
+	UNUSED(task);
+
+	free_rbtdb(rbtdb, ISC_TRUE, event);
+}
+
+static void
+free_rbtdb(dns_rbtdb_t *rbtdb, isc_boolean_t log, isc_event_t *event) {
 	unsigned int i;
 	isc_ondestroy_t ondest;
-	isc_mem_t *mctx;
+	isc_result_t result;
+	char buf[DNS_NAME_FORMATSIZE];
 
 	REQUIRE(EMPTY(rbtdb->open_versions));
 	REQUIRE(rbtdb->future_version == NULL);
@@ -393,23 +410,53 @@ free_rbtdb(dns_rbtdb_t *rbtdb) {
 	if (rbtdb->current_version != NULL)
 		isc_mem_put(rbtdb->common.mctx, rbtdb->current_version,
 			    sizeof(rbtdb_version_t));
+ again:
+	if (rbtdb->tree != NULL) {
+		result = dns_rbt_destroy2(&rbtdb->tree,
+					  (rbtdb->task != NULL) ? 5 : 0);
+		if (result == ISC_R_QUOTA) {
+			INSIST(rbtdb->task != NULL);
+			if (event == NULL)
+				event = isc_event_allocate(rbtdb->common.mctx,
+							   NULL,
+						         DNS_EVENT_FREESTORAGE,
+							   free_rbtdb_callback,
+							   rbtdb,
+							   sizeof(isc_event_t));
+			if (event == NULL)
+				goto again;
+			isc_task_send(rbtdb->task, &event);
+			return;
+		}
+		INSIST(result == ISC_R_SUCCESS && rbtdb->tree == NULL);
+	}
+	if (event != NULL)
+		isc_event_free(&event);
+	if (log) {
+		if (dns_name_dynamic(&rbtdb->common.origin))
+			dns_name_format(&rbtdb->common.origin, buf,
+					sizeof(buf));
+		else
+			strcpy(buf, "<UNKNOWN>");
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+			      DNS_LOGMODULE_CACHE, ISC_LOG_DEBUG(1),
+			      "done free_rbtdb(%s)", buf);
+	}
 	if (dns_name_dynamic(&rbtdb->common.origin))
 		dns_name_free(&rbtdb->common.origin, rbtdb->common.mctx);
-	if (rbtdb->tree != NULL)
-		dns_rbt_destroy(&rbtdb->tree);
 	for (i = 0; i < rbtdb->node_lock_count; i++)
 		DESTROYLOCK(&rbtdb->node_locks[i].lock);
 	isc_mem_put(rbtdb->common.mctx, rbtdb->node_locks,
 		    rbtdb->node_lock_count * sizeof(rbtdb_nodelock_t));
 	isc_rwlock_destroy(&rbtdb->tree_lock);
 	isc_refcount_destroy(&rbtdb->references);
+	if (rbtdb->task != NULL)
+		isc_task_detach(&rbtdb->task);
 	DESTROYLOCK(&rbtdb->lock);
 	rbtdb->common.magic = 0;
 	rbtdb->common.impmagic = 0;
 	ondest = rbtdb->common.ondest;
-	mctx = rbtdb->common.mctx;
-	isc_mem_put(mctx, rbtdb, sizeof(*rbtdb));
-	isc_mem_detach(&mctx);
+	isc_mem_putanddetach(&rbtdb->common.mctx, rbtdb, sizeof(*rbtdb));
 	isc_ondestroy_notify(&ondest, rbtdb);
 }
 
@@ -439,8 +486,18 @@ maybe_free_rbtdb(dns_rbtdb_t *rbtdb) {
 		if (rbtdb->active == 0)
 			want_free = ISC_TRUE;
 		UNLOCK(&rbtdb->lock);
-		if (want_free)
-			free_rbtdb(rbtdb);
+		if (want_free) {
+			char buf[DNS_NAME_FORMATSIZE];
+			if (dns_name_dynamic(&rbtdb->common.origin))
+				dns_name_format(&rbtdb->common.origin, buf,
+						sizeof(buf));
+			else
+				strcpy(buf, "<UNKNOWN>");
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+				      DNS_LOGMODULE_CACHE, ISC_LOG_DEBUG(1),
+				      "calling free_rbtdb(%s)", buf);
+			free_rbtdb(rbtdb, ISC_TRUE, NULL);
+		}
 	}
 }
 
@@ -3166,8 +3223,18 @@ detachnode(dns_db_t *db, dns_dbnode_t **targetp) {
 		if (rbtdb->active == 0)
 			want_free = ISC_TRUE;
 		UNLOCK(&rbtdb->lock);
-		if (want_free)
-			free_rbtdb(rbtdb);
+		if (want_free) {
+			char buf[DNS_NAME_FORMATSIZE];
+			if (dns_name_dynamic(&rbtdb->common.origin))
+				dns_name_format(&rbtdb->common.origin, buf,
+						sizeof(buf));
+			else
+				strcpy(buf, "<UNKNOWN>");
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+				      DNS_LOGMODULE_CACHE, ISC_LOG_DEBUG(1),
+				      "calling free_rbtdb(%s)", buf);
+			free_rbtdb(rbtdb, ISC_TRUE, NULL);
+		}
 	}
 }
 
@@ -4552,6 +4619,22 @@ nodecount(dns_db_t *db) {
 	return (count);
 }
 
+static void
+settask(dns_db_t *db, isc_task_t *task) {
+	dns_rbtdb_t *rbtdb;
+
+	rbtdb = (dns_rbtdb_t *)db;
+
+	REQUIRE(VALID_RBTDB(rbtdb));
+
+	LOCK(&rbtdb->lock);
+	if (rbtdb->task != NULL)
+		isc_task_detach(&rbtdb->task);
+	if (task != NULL)
+		isc_task_attach(task, &rbtdb->task);
+	UNLOCK(&rbtdb->lock);
+}
+
 static isc_boolean_t
 ispersistent(dns_db_t *db) {
 	UNUSED(db);
@@ -4584,7 +4667,8 @@ static dns_dbmethods_t zone_methods = {
 	issecure,
 	nodecount,
 	ispersistent,
-	overmem
+	overmem,
+	settask
 };
 
 static dns_dbmethods_t cache_methods = {
@@ -4613,7 +4697,8 @@ static dns_dbmethods_t cache_methods = {
 	issecure,
 	nodecount,
 	ispersistent,
-	overmem
+	overmem,
+	settask
 };
 
 isc_result_t
@@ -4714,7 +4799,7 @@ dns_rbtdb_create
 	 */
 	result = dns_name_dupwithoffsets(origin, mctx, &rbtdb->common.origin);
 	if (result != ISC_R_SUCCESS) {
-		free_rbtdb(rbtdb);
+		free_rbtdb(rbtdb, ISC_FALSE, NULL);
 		return (result);
 	}
 
@@ -4723,7 +4808,7 @@ dns_rbtdb_create
 	 */
 	result = dns_rbt_create(mctx, delete_callback, rbtdb, &rbtdb->tree);
 	if (result != ISC_R_SUCCESS) {
-		free_rbtdb(rbtdb);
+		free_rbtdb(rbtdb, ISC_FALSE, NULL);
 		return (result);
 	}
 	/*
@@ -4745,7 +4830,7 @@ dns_rbtdb_create
 					 &rbtdb->origin_node);
 		if (result != ISC_R_SUCCESS) {
 			INSIST(result != ISC_R_EXISTS);
-			free_rbtdb(rbtdb);
+			free_rbtdb(rbtdb, ISC_FALSE, NULL);
 			return (result);
 		}
 		/*
@@ -4771,6 +4856,7 @@ dns_rbtdb_create
 	rbtdb->attributes = 0;
 	rbtdb->secure = ISC_FALSE;
 	rbtdb->overmem = ISC_FALSE;
+	rbtdb->task = NULL;
 
 	/*
 	 * Version Initialization.
@@ -4780,7 +4866,7 @@ dns_rbtdb_create
 	rbtdb->next_serial = 2;
 	rbtdb->current_version = allocate_version(mctx, 1, 0, ISC_FALSE);
 	if (rbtdb->current_version == NULL) {
-		free_rbtdb(rbtdb);
+		free_rbtdb(rbtdb, ISC_FALSE, NULL);
 		return (ISC_R_NOMEMORY);
 	}
 	rbtdb->future_version = NULL;
diff --git a/lib/dns/sdb.c b/lib/dns/sdb.c
index 60c048cc18..6ebe385079 100644
--- a/lib/dns/sdb.c
+++ b/lib/dns/sdb.c
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: sdb.c,v 1.43 2004/02/27 20:41:44 marka Exp $ */
+/* $Id: sdb.c,v 1.44 2004/03/04 06:56:39 marka Exp $ */
 
 #include <config.h>
 
@@ -1200,6 +1200,12 @@ overmem(dns_db_t *db, isc_boolean_t overmem) {
 	UNUSED(overmem);
 }
 
+static void
+settask(dns_db_t *db, isc_task_t *task) {
+	UNUSED(db);
+	UNUSED(task);
+}
+
 
 static dns_dbmethods_t sdb_methods = {
 	attach,
@@ -1227,7 +1233,8 @@ static dns_dbmethods_t sdb_methods = {
 	issecure,
 	nodecount,
 	ispersistent,
-	overmem
+	overmem,
+	settask
 };
 
 static isc_result_t
diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index e04eac53d0..20b217db32 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: zone.c,v 1.407 2004/03/02 02:37:11 marka Exp $ */
+/* $Id: zone.c,v 1.408 2004/03/04 06:56:39 marka Exp $ */
 
 #include <config.h>
 
@@ -1046,6 +1046,7 @@ zone_load(dns_zone_t *zone, unsigned int flags) {
 			     isc_result_totext(result));
 		goto cleanup;
 	}
+	dns_db_settask(db, zone->task);
 
 	if (! dns_db_ispersistent(db)) {
 		if (zone->masterfile != NULL) {
@@ -4049,6 +4050,7 @@ ns_query(dns_zone_t *zone, dns_rdataset_t *soardataset, dns_stub_t *stub) {
 					     dns_result_totext(result));
 				goto cleanup;
 			}
+			dns_db_settask(stub->db, zone->task);
 		}
 
 		dns_db_newversion(stub->db, &stub->version);
@@ -5079,6 +5081,8 @@ dns_zone_settask(dns_zone_t *zone, isc_task_t *task) {
 	if (zone->task != NULL)
 		isc_task_detach(&zone->task);
 	isc_task_attach(task, &zone->task);
+	if (zone->db != NULL)
+		dns_db_settask(zone->db, zone->task);
 	UNLOCK_ZONE(zone);
 }
 
@@ -5267,6 +5271,7 @@ zone_replacedb(dns_zone_t *zone, dns_db_t *db, isc_boolean_t dump) {
 	if (zone->db != NULL)
 		dns_db_detach(&zone->db);
 	dns_db_attach(db, &zone->db);
+	dns_db_settask(zone->db, zone->task);
 	DNS_ZONE_SETFLAG(zone, DNS_ZONEFLG_LOADED|DNS_ZONEFLG_NEEDNOTIFY);
 	return (ISC_R_SUCCESS);
 
diff --git a/lib/isc/task.c b/lib/isc/task.c
index 4d8431915b..3027493604 100644
--- a/lib/isc/task.c
+++ b/lib/isc/task.c
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: task.c,v 1.89 2003/10/25 00:09:13 jinmei Exp $ */
+/* $Id: task.c,v 1.90 2004/03/04 06:56:41 marka Exp $ */
 
 /*
  * Principal Author: Bob Halley
@@ -1132,7 +1132,7 @@ isc_taskmgr_create(isc_mem_t *mctx, unsigned int workers,
 	}
 	isc_thread_setconcurrency(workers);
 #else /* ISC_PLATFORM_USETHREADS */
-	manager->refs = 0;
+	manager->refs = 1;
 	taskmgr = manager;
 #endif /* ISC_PLATFORM_USETHREADS */