Merge pull request #1713 from wiredtiger/shared-cache-reconfigure-bug

Fix a bug in the reconfigure API related to shared cache quotas.

8 files changed, 261 insertions, 66 deletions

diff --git a/src/conn/conn_api.c b/src/conn/conn_api.c
index 0562f9cfc34..6b9824fc415 100644
--- a/src/conn/conn_api.c
+++ b/src/conn/conn_api.c
@@ -762,8 +762,7 @@ __conn_reconfigure(WT_CONNECTION *wt_conn, const char *config)
 
 	WT_ERR(__conn_statistics_config(session, config_cfg));
 	WT_ERR(__wt_async_reconfig(session, config_cfg));
-	WT_ERR(__wt_cache_config(session, config_cfg));
-	WT_ERR(__wt_cache_pool_config(session, config_cfg));
+	WT_ERR(__wt_cache_config(session, 1, config_cfg));
 	WT_ERR(__wt_checkpoint_server_create(session, config_cfg));
 	WT_ERR(__wt_lsm_manager_reconfig(session, config_cfg));
 	WT_ERR(__wt_statlog_create(session, config_cfg));
diff --git a/src/conn/conn_cache.c b/src/conn/conn_cache.c
index c513d46137c..4a7e15044de 100644
--- a/src/conn/conn_cache.c
+++ b/src/conn/conn_cache.c
@@ -9,33 +9,28 @@
 #include "wt_internal.h"
 
 /*
- * __wt_cache_config --
+ * __cache_config_local --
  *	Configure the underlying cache.
  */
-int
-__wt_cache_config(WT_SESSION_IMPL *session, const char *cfg[])
+static int
+__cache_config_local(WT_SESSION_IMPL *session, int shared, const char *cfg[])
 {
 	WT_CACHE *cache;
 	WT_CONFIG_ITEM cval;
 	WT_CONNECTION_IMPL *conn;
+	uint32_t evict_workers_max, evict_workers_min;
 
 	conn = S2C(session);
 	cache = conn->cache;
 
 	/*
 	 * If not using a shared cache configure the cache size, otherwise
-	 * check for a reserved size.
+	 * check for a reserved size. All other settings are independent of
+	 * whether we are using a shared cache or not.
 	 */
-	if (!F_ISSET(conn, WT_CONN_CACHE_POOL)) {
+	if (!shared) {
 		WT_RET(__wt_config_gets(session, cfg, "cache_size", &cval));
 		conn->cache_size = (uint64_t)cval.val;
-	} else {
-		WT_RET(__wt_config_gets(
-		    session, cfg, "shared_cache.reserve", &cval));
-		if (cval.val == 0)
-			WT_RET(__wt_config_gets(
-			    session, cfg, "shared_cache.chunk", &cval));
-		cache->cp_reserved = (uint64_t)cval.val;
 	}
 
 	WT_RET(__wt_config_gets(session, cfg, "cache_overhead", &cval));
@@ -57,16 +52,64 @@ __wt_cache_config(WT_SESSION_IMPL *session, const char *cfg[])
 	 */
 	WT_RET(__wt_config_gets(session, cfg, "eviction.threads_max", &cval));
 	WT_ASSERT(session, cval.val > 0);
-	conn->evict_workers_max = (u_int)cval.val - 1;
+	evict_workers_max = (uint32_t)cval.val - 1;
 
 	WT_RET(__wt_config_gets(session, cfg, "eviction.threads_min", &cval));
 	WT_ASSERT(session, cval.val > 0);
-	conn->evict_workers_min = (u_int)cval.val - 1;
+	evict_workers_min = (uint32_t)cval.val - 1;
 
-	if (conn->evict_workers_min > conn->evict_workers_max)
+	if (evict_workers_min > evict_workers_max)
 		WT_RET_MSG(session, EINVAL,
 		    "eviction=(threads_min) cannot be greater than "
 		    "eviction=(threads_max)");
+	conn->evict_workers_max = evict_workers_max;
+	conn->evict_workers_min = evict_workers_min;
+
+	return (0);
+}
+
+/*
+ * __wt_cache_config --
+ *	Configure or reconfigure the current cache and shared cache.
+ */
+int
+__wt_cache_config(WT_SESSION_IMPL *session, int reconfigure, const char *cfg[])
+{
+	WT_CONFIG_ITEM cval;
+	WT_CONNECTION_IMPL *conn;
+	int now_shared, was_shared;
+
+	conn = S2C(session);
+
+	WT_ASSERT(session, conn->cache != NULL);
+
+	WT_RET(__wt_config_gets_none(session, cfg, "shared_cache.name", &cval));
+	now_shared = cval.len != 0;
+	was_shared = F_ISSET(conn, WT_CONN_CACHE_POOL);
+
+	/* Cleanup if reconfiguring */
+	if (reconfigure && was_shared && !now_shared)
+		/* Remove ourselves from the pool if necessary */
+		WT_RET(__wt_conn_cache_pool_destroy(session));
+	else if (reconfigure && !was_shared && now_shared)
+		/*
+		 * Cache size will now be managed by the cache pool - the
+		 * start size always needs to be zero to allow the pool to
+		 * manage how much memory is in-use.
+		 */
+		conn->cache_size = 0;
+
+	/*
+	 * Always setup the local cache - it's used even if we are
+	 * participating in a shared cache.
+	 */
+	WT_RET(__cache_config_local(session, now_shared, cfg));
+	if (now_shared) {
+		WT_RET(__wt_cache_pool_config(session, cfg));
+		WT_ASSERT(session, F_ISSET(conn, WT_CONN_CACHE_POOL));
+		if (!was_shared)
+			WT_RET(__wt_conn_cache_pool_open(session));
+	}
 
 	return (0);
 }
@@ -84,19 +127,14 @@ __wt_cache_create(WT_SESSION_IMPL *session, const char *cfg[])
 
 	conn = S2C(session);
 
-	WT_ASSERT(session, conn->cache == NULL ||
-	    (F_ISSET(conn, WT_CONN_CACHE_POOL) && conn->cache != NULL));
+	WT_ASSERT(session, conn->cache == NULL);
 
 	WT_RET(__wt_calloc_one(session, &conn->cache));
 
 	cache = conn->cache;
 
 	/* Use a common routine for run-time configuration options. */
-	WT_RET(__wt_cache_config(session, cfg));
-
-	/* Add the configured cache to the cache pool. */
-	if (F_ISSET(conn, WT_CONN_CACHE_POOL))
-		WT_RET(__wt_conn_cache_pool_open(session));
+	WT_RET(__wt_cache_config(session, 0, cfg));
 
 	/*
 	 * The target size must be lower than the trigger size or we will never
diff --git a/src/conn/conn_cache_pool.c b/src/conn/conn_cache_pool.c
index f5b78e33b04..7bf090496a8 100644
--- a/src/conn/conn_cache_pool.c
+++ b/src/conn/conn_cache_pool.c
@@ -36,17 +36,17 @@ __wt_cache_pool_config(WT_SESSION_IMPL *session, const char **cfg)
 	WT_CONNECTION_IMPL *conn, *entry;
 	WT_DECL_RET;
 	char *pool_name;
-	int created, reconfiguring;
+	int created, updating;
 	uint64_t chunk, reserve, size, used_cache;
 
 	conn = S2C(session);
-	created = reconfiguring = 0;
+	created = updating = 0;
 	pool_name = NULL;
 	cp = NULL;
 	size = 0;
 
 	if (F_ISSET(conn, WT_CONN_CACHE_POOL))
-		reconfiguring = 1;
+		updating = 1;
 	else {
 		WT_RET(__wt_config_gets_none(
 		    session, cfg, "shared_cache.name", &cval));
@@ -81,7 +81,7 @@ __wt_cache_pool_config(WT_SESSION_IMPL *session, const char **cfg)
 
 	__wt_spin_lock(session, &__wt_process.spinlock);
 	if (__wt_process.cache_pool == NULL) {
-		WT_ASSERT(session, !reconfiguring);
+		WT_ASSERT(session, !updating);
 		/* Create a cache pool. */
 		WT_ERR(__wt_calloc_one(session, &cp));
 		created = 1;
@@ -96,7 +96,7 @@ __wt_cache_pool_config(WT_SESSION_IMPL *session, const char **cfg)
 		__wt_process.cache_pool = cp;
 		WT_ERR(__wt_verbose(session,
 		    WT_VERB_SHARED_CACHE, "Created cache pool %s", cp->name));
-	} else if (!reconfiguring && !WT_STRING_MATCH(
+	} else if (!updating && !WT_STRING_MATCH(
 	    __wt_process.cache_pool->name, pool_name, strlen(pool_name)))
 		/* Only a single cache pool is supported. */
 		WT_ERR_MSG(session, WT_ERROR,
@@ -109,7 +109,7 @@ __wt_cache_pool_config(WT_SESSION_IMPL *session, const char **cfg)
 	 * The cache pool requires a reference count to avoid a race between
 	 * configuration/open and destroy.
 	 */
-	if (!reconfiguring)
+	if (!updating)
 		++cp->refs;
 
 	/*
@@ -157,7 +157,7 @@ __wt_cache_pool_config(WT_SESSION_IMPL *session, const char **cfg)
 	if (__wt_config_gets(session, &cfg[1],
 	    "shared_cache.reserve", &cval) == 0 && cval.val != 0)
 		reserve = (uint64_t)cval.val;
-	else if (reconfiguring)
+	else if (updating)
 		reserve = conn->cache->cp_reserved;
 	else
 		reserve = chunk;
@@ -171,18 +171,23 @@ __wt_cache_pool_config(WT_SESSION_IMPL *session, const char **cfg)
 		TAILQ_FOREACH(entry, &cp->cache_pool_qh, cpq)
 			used_cache += entry->cache->cp_reserved;
 	}
+	/* Ignore our old allocation if reconfiguring */
+	if (updating)
+		used_cache -= conn->cache->cp_reserved;
 	if (used_cache + reserve > size)
 		WT_ERR_MSG(session, EINVAL,
 		    "Shared cache unable to accommodate this configuration. "
-		    "Shared cache size: %" PRIu64 ", reserved: %" PRIu64,
+		    "Shared cache size: %" PRIu64 ", requested min: %" PRIu64,
 		    size, used_cache + reserve);
 
 	/* The configuration is verified - it's safe to update the pool. */
 	cp->size = size;
 	cp->chunk = chunk;
 
+	conn->cache->cp_reserved = reserve;
+
 	/* Wake up the cache pool server so any changes are noticed. */
-	if (reconfiguring)
+	if (updating)
 		WT_ERR(__wt_cond_signal(
 		    session, __wt_process.cache_pool->cache_pool_cond));
 
@@ -192,7 +197,7 @@ __wt_cache_pool_config(WT_SESSION_IMPL *session, const char **cfg)
 
 	F_SET(conn, WT_CONN_CACHE_POOL);
 err:	__wt_spin_unlock(session, &__wt_process.spinlock);
-	if (!reconfiguring)
+	if (!updating)
 		__wt_free(session, pool_name);
 	if (ret != 0 && created) {
 		__wt_free(session, cp->name);
diff --git a/src/conn/conn_open.c b/src/conn/conn_open.c
index bc1d9eaf01a..0a3d35ac0b1 100644
--- a/src/conn/conn_open.c
+++ b/src/conn/conn_open.c
@@ -55,9 +55,6 @@ __wt_connection_open(WT_CONNECTION_IMPL *conn, const char *cfg[])
 	 */
 	WT_WRITE_BARRIER();
 
-	/* Connect to a cache pool. */
-	WT_RET(__wt_cache_pool_config(session, cfg));
-
 	/* Create the cache. */
 	WT_RET(__wt_cache_create(session, cfg));
 
diff --git a/src/evict/evict_lru.c b/src/evict/evict_lru.c
index bc479159cd7..640c9b0541d 100644
--- a/src/evict/evict_lru.c
+++ b/src/evict/evict_lru.c
@@ -248,7 +248,7 @@ __evict_workers_resize(WT_SESSION_IMPL *session)
 	WT_DECL_RET;
 	WT_EVICT_WORKER *workers;
 	size_t alloc;
-	u_int i;
+	uint32_t i;
 
 	conn = S2C(session);
 
@@ -332,7 +332,7 @@ __wt_evict_destroy(WT_SESSION_IMPL *session)
 	WT_DECL_RET;
 	WT_EVICT_WORKER *workers;
 	WT_SESSION *wt_session;
-	u_int i;
+	uint32_t i;
 
 	conn = S2C(session);
 	cache = conn->cache;
diff --git a/src/include/extern.h b/src/include/extern.h
index c6628ffdc1c..0ef055e1162 100644
--- a/src/include/extern.h
+++ b/src/include/extern.h
@@ -207,7 +207,7 @@ extern int __wt_conn_remove_data_source(WT_SESSION_IMPL *session);
 extern int __wt_extractor_config(WT_SESSION_IMPL *session, const char *config, WT_EXTRACTOR **extractorp, int *ownp);
 extern int __wt_conn_remove_extractor(WT_SESSION_IMPL *session);
 extern int __wt_verbose_config(WT_SESSION_IMPL *session, const char *cfg[]);
-extern int __wt_cache_config(WT_SESSION_IMPL *session, const char *cfg[]);
+extern int __wt_cache_config(WT_SESSION_IMPL *session, int reconfigure, const char *cfg[]);
 extern int __wt_cache_create(WT_SESSION_IMPL *session, const char *cfg[]);
 extern void __wt_cache_stats_update(WT_SESSION_IMPL *session);
 extern int __wt_cache_destroy(WT_SESSION_IMPL *session);
diff --git a/test/suite/test_shared_cache.py b/test/suite/test_shared_cache01.py
index ff40d31e6df..e6d712e61bc 100644
--- a/test/suite/test_shared_cache.py
+++ b/test/suite/test_shared_cache01.py
@@ -33,12 +33,12 @@ import wiredtiger, wttest
 from wttest import unittest
 from helper import key_populate, simple_populate
 
-# test_shared_cache.py
+# test_shared_cache01.py
 #    Checkpoint tests
 # Test shared cache shared amongst multiple connections.
-class test_shared_cache(wttest.WiredTigerTestCase):
+class test_shared_cache01(wttest.WiredTigerTestCase):
 
-    uri = 'table:test_shared_cache'
+    uri = 'table:test_shared_cache01'
     # Setup fairly large items to use up cache
     data_str = 'abcdefghijklmnopqrstuvwxyz' * 20
 
@@ -89,7 +89,7 @@ class test_shared_cache(wttest.WiredTigerTestCase):
         self.sessions = [] # Implicitly closed when closing sessions.
 
     # Basic test of shared cache
-    def test_shared_cache01(self):
+    def test_shared_cache_basic(self):
         nops = 1000
         self.openConnections(['WT_TEST1', 'WT_TEST2'])
 
@@ -99,7 +99,7 @@ class test_shared_cache(wttest.WiredTigerTestCase):
         self.closeConnections()
 
     # Test of shared cache with more connections
-    def test_shared_cache02(self):
+    def test_shared_cache_more_connections(self):
         nops = 1000
         self.openConnections(['WT_TEST1', 'WT_TEST2', 'WT_TEST3', 'WT_TEST4'])
 
@@ -109,7 +109,7 @@ class test_shared_cache(wttest.WiredTigerTestCase):
         self.closeConnections()
 
     # Do enough work for the shared cache to be fully allocated.
-    def test_shared_cache03(self):
+    def test_shared_cache_full(self):
         nops = 10000
         self.openConnections(['WT_TEST1', 'WT_TEST2'])
         for sess in self.sessions:
@@ -121,7 +121,7 @@ class test_shared_cache(wttest.WiredTigerTestCase):
         self.closeConnections()
 
     # Switch the work between connections, to test rebalancing.
-    def test_shared_cache04(self):
+    def test_shared_cache_rebalance(self):
         # About 100 MB of data with ~250 byte values.
         nops = 200000
         self.openConnections(['WT_TEST1', 'WT_TEST2'])
@@ -132,7 +132,7 @@ class test_shared_cache(wttest.WiredTigerTestCase):
         self.closeConnections()
 
     # Add a new connection once the shared cache is already established.
-    def test_shared_cache05(self):
+    def test_shared_cache_late_join(self):
         nops = 1000
         self.openConnections(['WT_TEST1', 'WT_TEST2'])
 
@@ -147,7 +147,7 @@ class test_shared_cache(wttest.WiredTigerTestCase):
         self.closeConnections()
 
     # Close a connection and keep using other connections.
-    def test_shared_cache06(self):
+    def test_shared_cache_leaving(self):
         nops = 10000
         self.openConnections(['WT_TEST1', 'WT_TEST2', 'WT_TEST3'])
 
@@ -163,7 +163,7 @@ class test_shared_cache(wttest.WiredTigerTestCase):
 
     # Test verbose output
     @unittest.skip("Verbose output handling")
-    def test_shared_cache07(self):
+    def test_shared_cache_verbose(self):
         nops = 1000
         self.openConnections(
                 ['WT_TEST1', 'WT_TEST2'], extra_opts="verbose=[shared_cache]")
@@ -174,7 +174,7 @@ class test_shared_cache(wttest.WiredTigerTestCase):
         self.closeConnections()
 
     # Test opening a connection outside of the shared cache
-    def test_shared_cache08(self):
+    def test_shared_cache_mixed(self):
         nops = 1000
         self.openConnections(['WT_TEST1', 'WT_TEST2'])
 
@@ -185,7 +185,7 @@ class test_shared_cache(wttest.WiredTigerTestCase):
         self.closeConnections()
 
     # Test default config values
-    def test_shared_cache09(self):
+    def test_shared_cache_defaults(self):
         nops = 1000
         self.openConnections(['WT_TEST1', 'WT_TEST2'], pool_opts=',shared_cache=(name=pool,size=200M)')
 
@@ -194,21 +194,8 @@ class test_shared_cache(wttest.WiredTigerTestCase):
             self.add_records(sess, 0, nops)
         self.closeConnections()
 
-    # Test reconfigure API
-    def test_shared_cache10(self):
-        nops = 1000
-        self.openConnections(['WT_TEST1', 'WT_TEST2'])
-
-        for sess in self.sessions:
-            sess.create(self.uri, "key_format=S,value_format=S")
-            self.add_records(sess, 0, nops)
-
-        connection = self.conns[0]
-        connection.reconfigure("shared_cache=(name=pool,size=300M)")
-        self.closeConnections()
-
     # Test default config values
-    def test_shared_cache11(self):
+    def test_shared_cache_defaults2(self):
         nops = 1000
         self.openConnections(['WT_TEST1', 'WT_TEST2'], pool_opts=',shared_cache=(name=pool)')
 
diff --git a/test/suite/test_shared_cache02.py b/test/suite/test_shared_cache02.py
new file mode 100644
index 00000000000..3806e9d0cda
--- /dev/null
+++ b/test/suite/test_shared_cache02.py
@@ -0,0 +1,169 @@
+#!/usr/bin/env python
+#
+# Public Domain 2014-2015 MongoDB, Inc.
+# Public Domain 2008-2014 WiredTiger, Inc.
+#
+# This is free and unencumbered software released into the public domain.
+#
+# Anyone is free to copy, modify, publish, use, compile, sell, or
+# distribute this software, either in source code form or as a compiled
+# binary, for any purpose, commercial or non-commercial, and by any
+# means.
+#
+# In jurisdictions that recognize copyright laws, the author or authors
+# of this software dedicate any and all copyright interest in the
+# software to the public domain. We make this dedication for the benefit
+# of the public at large and to the detriment of our heirs and
+# successors. We intend this dedication to be an overt act of
+# relinquishment in perpetuity of all present and future rights to this
+# software under copyright law.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+# IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+# OTHER DEALINGS IN THE SOFTWARE.
+# If unittest2 is available, use it in preference to (the old) unittest
+
+import os
+import shutil
+import wiredtiger, wttest
+from wttest import unittest
+from helper import key_populate, simple_populate
+
+# test_shared_cache02.py
+#    Shared cache tests
+# Test shared cache shared amongst multiple connections.
+class test_shared_cache02(wttest.WiredTigerTestCase):
+
+    uri = 'table:test_shared_cache02'
+    # Setup fairly large items to use up cache
+    data_str = 'abcdefghijklmnopqrstuvwxyz' * 20
+
+    # Add a set of records
+    def add_records(self, session, start, stop):
+        cursor = session.open_cursor(self.uri, None, "overwrite")
+        for i in range(start, stop+1):
+            cursor.set_key("%010d KEY------" % i)
+            cursor.set_value("%010d VALUE "% i + self.data_str)
+            self.assertEqual(cursor.insert(), 0)
+        cursor.close()
+
+    # Disable default setup/shutdown steps - connections are managed manually.
+    def setUpSessionOpen(self, conn):
+        return None
+
+    def close_conn(self):
+        return None
+
+    def setUpConnectionOpen(self, dir):
+        return None
+
+    def openConnections(
+            self,
+            connections,
+            pool_opts = ',shared_cache=(name=pool,size=200M,chunk=10M,reserve=30M),',
+            extra_opts = '',
+            add=0):
+        if add == 0:
+            self.conns = []
+            self.sessions = []
+        # Open the set of connections.
+        for name in connections:
+            shutil.rmtree(name, True)
+            os.mkdir(name)
+            next_conn =  wiredtiger.wiredtiger_open(
+                name,
+                'create,error_prefix="' + self.shortid() + ': "' +
+                pool_opts + extra_opts)
+            self.conns.append(next_conn)
+            self.sessions.append(next_conn.open_session(None))
+        return None
+
+    def closeConnections(self):
+        for tmp_conn in self.conns:
+            tmp_conn.close()
+        self.conns = []
+        self.sessions = [] # Implicitly closed when closing sessions.
+
+    # Test reconfigure API
+    def test_shared_cache_reconfig01(self):
+        nops = 1000
+        self.openConnections(['WT_TEST1', 'WT_TEST2'])
+
+        for sess in self.sessions:
+            sess.create(self.uri, "key_format=S,value_format=S")
+            self.add_records(sess, 0, nops)
+
+        connection = self.conns[0]
+        connection.reconfigure("shared_cache=(name=pool,size=300M)")
+        self.closeConnections()
+
+    # Test reconfigure that grows the usage over quota fails
+    def test_shared_cache_reconfig02(self):
+        nops = 1000
+        self.openConnections(['WT_TEST1', 'WT_TEST2'],
+            pool_opts = ',shared_cache=(name=pool,size=50M,reserve=20M),')
+
+        for sess in self.sessions:
+            sess.create(self.uri, "key_format=S,value_format=S")
+            self.add_records(sess, 0, nops)
+
+        connection = self.conns[0]
+        # Reconfigure to over-subscribe, call should fail with an error
+        self.assertRaisesWithMessage(wiredtiger.WiredTigerError,
+            lambda: connection.reconfigure("shared_cache=(name=pool,reserve=40M)"),
+            '/Shared cache unable to accommodate this configuration/')
+        # TODO: Ensure that the reserve size wasn't updated.
+        # cursor = self.sessions[0].open_cursor('config:', None, None)
+        # value = cursor['connection']
+        # self.assertTrue(value.find('reserve') != -1)
+
+        self.closeConnections()
+
+    # Test reconfigure that would grow the usage over quota if the
+    # previous reserve size isn't taken into account
+    def test_shared_cache_reconfig03(self):
+        nops = 1000
+        self.openConnections(['WT_TEST1', 'WT_TEST2'],
+            pool_opts = ',shared_cache=(name=pool,size=50M,reserve=20M),')
+
+        for sess in self.sessions:
+            sess.create(self.uri, "key_format=S,value_format=S")
+            self.add_records(sess, 0, nops)
+
+        connection = self.conns[0]
+
+        connection.reconfigure("shared_cache=(name=pool,reserve=30M)"),
+
+        # TODO: Ensure that the reserve size was updated.
+        # cursor = self.sessions[0].open_cursor('config:', None, None)
+        # value = cursor['connection']
+        # self.assertTrue(value.find('reserve') != -1)
+
+        self.closeConnections()
+
+    # Test reconfigure that switches to using a shared cache
+    # previous reserve size isn't taken into account
+    def test_shared_cache_reconfig03(self):
+        nops = 1000
+        self.openConnections(['WT_TEST1', 'WT_TEST2'], pool_opts = ',')
+
+        for sess in self.sessions:
+            sess.create(self.uri, "key_format=S,value_format=S")
+            self.add_records(sess, 0, nops)
+
+        self.conns[0].reconfigure("shared_cache=(name=pool,reserve=20M)"),
+        self.conns[1].reconfigure("shared_cache=(name=pool,reserve=20M)"),
+
+        # TODO: Ensure that the reserve size was updated.
+        # cursor = self.sessions[0].open_cursor('config:', None, None)
+        # value = cursor['connection']
+        # self.assertTrue(value.find('reserve') != -1)
+
+        self.closeConnections()
+
+if __name__ == '__main__':
+    wttest.run()