diff --git a/neo4j/io/__init__.py b/neo4j/io/__init__.py
index 20ac1122..7d52c336 100644
--- a/neo4j/io/__init__.py
+++ b/neo4j/io/__init__.py
@@ -58,7 +58,6 @@
 )
 from threading import (
     Condition,
-    Lock,
     RLock,
 )
 from time import perf_counter
@@ -875,7 +874,7 @@ def __init__(self, opener, pool_config, workspace_config, address):
         log.debug("[#0000]  C: <NEO4J POOL> routing address %r", address)
         self.address = address
         self.routing_tables = {workspace_config.database: RoutingTable(database=workspace_config.database, routers=[address])}
-        self.refresh_lock = Lock()
+        self.refresh_lock = RLock()
 
     def __repr__(self):
         """ The representation shows the initial routing addresses.
@@ -1109,23 +1108,25 @@ def _select_address(self, *, access_mode, database, bookmarks):
         from neo4j.api import READ_ACCESS
         """ Selects the address with the fewest in-use connections.
         """
-        self.create_routing_table(database)
-        self.ensure_routing_table_is_fresh(
-            access_mode=access_mode, database=database, bookmarks=bookmarks
-        )
-        log.debug("[#0000]  C: <ROUTING TABLE ENSURE FRESH> %r", self.routing_tables)
-        if access_mode == READ_ACCESS:
-            addresses = self.routing_tables[database].readers
-        else:
-            addresses = self.routing_tables[database].writers
-        addresses_by_usage = {}
-        for address in addresses:
-            addresses_by_usage.setdefault(self.in_use_connection_count(address), []).append(address)
+        with self.refresh_lock:
+            if access_mode == READ_ACCESS:
+                addresses = self.routing_tables[database].readers
+            else:
+                addresses = self.routing_tables[database].writers
+            addresses_by_usage = {}
+            for address in addresses:
+                addresses_by_usage.setdefault(
+                    self.in_use_connection_count(address), []
+                ).append(address)
         if not addresses_by_usage:
             if access_mode == READ_ACCESS:
-                raise ReadServiceUnavailable("No read service currently available")
+                raise ReadServiceUnavailable(
+                    "No read service currently available"
+                )
             else:
-                raise WriteServiceUnavailable("No write service currently available")
+                raise WriteServiceUnavailable(
+                    "No write service currently available"
+                )
         return choice(addresses_by_usage[min(addresses_by_usage)])
 
     def acquire(self, access_mode=None, timeout=None, database=None,
@@ -1137,6 +1138,13 @@ def acquire(self, access_mode=None, timeout=None, database=None,
 
         from neo4j.api import check_access_mode
         access_mode = check_access_mode(access_mode)
+        with self.refresh_lock:
+            self.create_routing_table(database)
+            log.debug("[#0000]  C: <ROUTING TABLE ENSURE FRESH> %r", self.routing_tables)
+            self.ensure_routing_table_is_fresh(
+                access_mode=access_mode, database=database, bookmarks=bookmarks
+            )
+
         while True:
             try:
                 # Get an address for a connection that have the fewest in-use connections.
@@ -1144,10 +1152,10 @@ def acquire(self, access_mode=None, timeout=None, database=None,
                     access_mode=access_mode, database=database,
                     bookmarks=bookmarks
                 )
-                log.debug("[#0000]  C: <ACQUIRE ADDRESS> database=%r address=%r", database, address)
             except (ReadServiceUnavailable, WriteServiceUnavailable) as err:
                 raise SessionExpired("Failed to obtain connection towards '%s' server." % access_mode) from err
             try:
+                log.debug("[#0000]  C: <ACQUIRE ADDRESS> database=%r address=%r", database, address)
                 connection = self._acquire(address, timeout=timeout)  # should always be a resolved address
             except ServiceUnavailable:
                 self.deactivate(address=address)
diff --git a/testkitbackend/requests.py b/testkitbackend/requests.py
index 70036e82..a23091fb 100644
--- a/testkitbackend/requests.py
+++ b/testkitbackend/requests.py
@@ -75,13 +75,18 @@ def NewDriver(backend, data):
     if data["resolverRegistered"] or data["domainNameResolverRegistered"]:
         resolver = resolution_func(backend, data["resolverRegistered"],
                                    data["domainNameResolverRegistered"])
-    connection_timeout = data.get("connectionTimeoutMs", None)
+    connection_timeout = data.get("connectionTimeoutMs")
     if connection_timeout is not None:
         connection_timeout /= 1000
+    max_transaction_retry_time = data.get("maxTxRetryTimeMs")
+    if max_transaction_retry_time is not None:
+        max_transaction_retry_time /= 1000
     data.mark_item_as_read("domainNameResolverRegistered")
     driver = neo4j.GraphDatabase.driver(
         data["uri"], auth=auth, user_agent=data["userAgent"],
-        resolver=resolver, connection_timeout=connection_timeout
+        resolver=resolver, connection_timeout=connection_timeout,
+        fetch_size=data.get("fetchSize"),
+        max_transaction_retry_time=max_transaction_retry_time,
     )
     key = backend.next_key()
     backend.drivers[key] = driver
@@ -304,6 +309,13 @@ def TransactionRollback(backend, data):
     backend.send_response("Transaction", {"id": key})
 
 
+def TransactionClose(backend, data):
+    key = data["txId"]
+    tx = backend.transactions[key]
+    tx.close()
+    backend.send_response("Transaction", {"id": key})
+
+
 def ResultNext(backend, data):
     result = backend.results[data["resultId"]]
     try:
diff --git a/testkitbackend/test_config.json b/testkitbackend/test_config.json
index 49287b8a..5c1291ab 100644
--- a/testkitbackend/test_config.json
+++ b/testkitbackend/test_config.json
@@ -32,13 +32,18 @@
     "Feature:Auth:Custom": true,
     "Feature:Auth:Kerberos": true,
     "AuthorizationExpiredTreatment": true,
+    "Optimization:ConnectionReuse": true,
+    "Optimization:EagerTransactionBegin": true,
     "Optimization:ImplicitDefaultArguments": true,
     "Optimization:MinimalResets": true,
-    "Optimization:ConnectionReuse": true,
     "Optimization:PullPipelining": true,
     "ConfHint:connection.recv_timeout_seconds": true,
-    "Temporary:ResultKeys": true,
+    "Temporary:CypherPathAndRelationship": true,
+    "Temporary:DriverFetchSize": true,
+    "Temporary:DriverMaxTxRetryTime": true,
     "Temporary:FullSummary": true,
-    "Temporary:CypherPathAndRelationship": true
+    "Temporary:ResultKeys": true,
+    "Temporary:ResultList": "requires further specification/discussion in the team",
+    "Temporary:TransactionClose": true
   }
 }