minor fixes

src/Common/GetPriorityForLoadBalancing.cpp

@@ -3,12 +3,19 @@
 namespace DB
 {
 
+namespace ErrorCodes
+{
+    extern const int LOGICAL_ERROR;
+}
+
 std::function<size_t(size_t index)> GetPriorityForLoadBalancing::getPriorityFunc(LoadBalancing load_balance, size_t offset, size_t pool_size) const
 {
     std::function<size_t(size_t index)> get_priority;
     switch (load_balance)
     {
         case LoadBalancing::NEAREST_HOSTNAME:
+            if (hostname_differences.empty())
+                throw Exception(ErrorCodes::LOGICAL_ERROR, "It's a bug: hostname_differences is not initialized");
             get_priority = [&](size_t i) { return hostname_differences[i]; };
             break;
         case LoadBalancing::IN_ORDER:

src/Common/GetPriorityForLoadBalancing.h

@@ -11,9 +11,14 @@ public:
     GetPriorityForLoadBalancing(LoadBalancing load_balancing_) : load_balancing(load_balancing_) {}
     GetPriorityForLoadBalancing(){}
 
-    bool operator!=(const GetPriorityForLoadBalancing & other)
+    bool operator == (const GetPriorityForLoadBalancing & other) const
     {
-        return load_balancing != other.load_balancing || hostname_differences != other.hostname_differences;
+        return load_balancing == other.load_balancing && hostname_differences == other.hostname_differences;
+    }
+
+    bool operator != (const GetPriorityForLoadBalancing & other) const
+    {
+        return !(*this == other);
     }
 
     std::function<size_t(size_t index)> getPriorityFunc(LoadBalancing load_balance, size_t offset, size_t pool_size) const;

src/Common/ZooKeeper/ZooKeeper.cpp

@@ -290,8 +290,8 @@ bool ZooKeeper::configChanged(const Poco::Util::AbstractConfiguration & config,
     if (args.get_priority_load_balancing != get_priority_load_balancing)
         return true;
 
-    return std::tie(args.implementation, args.hosts, args.identity, args.session_timeout_ms, args.operation_timeout_ms, args.chroot)
-        != std::tie(implementation, hosts, identity, session_timeout_ms, operation_timeout_ms, chroot);
+    return std::tie(args.implementation, args.hosts, args.identity, args.session_timeout_ms, args.operation_timeout_ms, args.chroot, args.get_priority_load_balancing)
+        != std::tie(implementation, hosts, identity, session_timeout_ms, operation_timeout_ms, chroot, args.get_priority_load_balancing);
 }
 
 

src/Common/ZooKeeper/ZooKeeper.h

@@ -13,8 +13,8 @@
 #include <Common/Stopwatch.h>
 #include <Common/ZooKeeper/IKeeper.h>
 #include <Common/ZooKeeper/ZooKeeperConstants.h>
-#include <Common/randomSeed.h>
 #include <Common/GetPriorityForLoadBalancing.h>
+#include <Common/thread_local_rng.h>
 #include <unistd.h>
 #include <random>
 
@@ -48,7 +48,7 @@ struct ShuffleHost
 
     void randomize()
     {
-        random = rng();
+        random = thread_local_rng();
     }
 
     static bool compare(const ShuffleHost & lhs, const ShuffleHost & rhs)
@@ -56,9 +56,6 @@ struct ShuffleHost
         return std::forward_as_tuple(lhs.priority, lhs.random)
                < std::forward_as_tuple(rhs.priority, rhs.random);
     }
-
-private:
-    std::minstd_rand rng = std::minstd_rand(randomSeed());
 };
 
 using GetPriorityForLoadBalancing = DB::GetPriorityForLoadBalancing;

src/Common/isLocalAddress.cpp

@@ -124,6 +124,7 @@ bool isLocalAddress(const Poco::Net::SocketAddress & address, UInt16 clickhouse_
 
 size_t getHostNameDifference(const std::string & local_hostname, const std::string & host)
 {
+    /// FIXME should we replace it with Levenstein distance? (we already have it in NamePrompter)
     size_t hostname_difference = 0;
     for (size_t i = 0; i < std::min(local_hostname.length(), host.length()); ++i)
         if (local_hostname[i] != host[i])

tests/integration/test_zookeeper_config_load_balancing/test.py

@@ -3,11 +3,12 @@ from helpers.cluster import ClickHouseCluster
 
 cluster = ClickHouseCluster(__file__, zookeeper_config_path='configs/zookeeper_load_balancing.xml')
 
-node1 = cluster.add_instance('node1', with_zookeeper=True,
+# use 3-letter hostnames, so getHostNameDifference("nod1", "zoo1") will work as expected
+node1 = cluster.add_instance('nod1', with_zookeeper=True,
                                 main_configs=["configs/zookeeper_load_balancing.xml"])
-node2 = cluster.add_instance('node2', with_zookeeper=True,
+node2 = cluster.add_instance('nod2', with_zookeeper=True,
                                 main_configs=["configs/zookeeper_load_balancing.xml"])
-node3 = cluster.add_instance('node3', with_zookeeper=True,
+node3 = cluster.add_instance('nod3', with_zookeeper=True,
                                 main_configs=["configs/zookeeper_load_balancing.xml"])
 
 def change_balancing(old, new, reload=True):
@@ -56,7 +57,7 @@ def test_in_order(started_cluster):
         print(str(node3.exec_in_container(['bash', '-c', "lsof -a -i4 -i6 -itcp -w | grep ':2181' | grep ESTABLISHED"], privileged=True, user='root')))
         assert '1' == str(node3.exec_in_container(['bash', '-c', "lsof -a -i4 -i6 -itcp -w | grep 'testzookeeperconfigloadbalancing_zoo1_1.*testzookeeperconfigloadbalancing_default:2181' | grep ESTABLISHED | wc -l"], privileged=True, user='root')).strip()
     finally:
-        change_balancing('first_or_random', 'random', reload=False)
+        change_balancing('in_order', 'random', reload=False)
 
 
 def test_nearest_hostname(started_cluster):
@@ -71,7 +72,7 @@ def test_nearest_hostname(started_cluster):
         print(str(node3.exec_in_container(['bash', '-c', "lsof -a -i4 -i6 -itcp -w | grep ':2181' | grep ESTABLISHED"], privileged=True, user='root')))
         assert '1' == str(node3.exec_in_container(['bash', '-c', "lsof -a -i4 -i6 -itcp -w | grep 'testzookeeperconfigloadbalancing_zoo3_1.*testzookeeperconfigloadbalancing_default:2181' | grep ESTABLISHED | wc -l"], privileged=True, user='root')).strip()
     finally:
-        change_balancing('first_or_random', 'random', reload=False)
+        change_balancing('nearest_hostname', 'random', reload=False)
 
 
 def test_round_robin(started_cluster):
@@ -88,6 +89,6 @@ def test_round_robin(started_cluster):
         print(str(node3.exec_in_container(['bash', '-c', "lsof -a -i4 -i6 -itcp -w | grep ':2181' | grep ESTABLISHED"], privileged=True, user='root')))
         assert '1' == str(node3.exec_in_container(['bash', '-c', "lsof -a -i4 -i6 -itcp -w | grep 'testzookeeperconfigloadbalancing_zoo2_1.*testzookeeperconfigloadbalancing_default:2181' | grep ESTABLISHED | wc -l"], privileged=True, user='root')).strip()
 
-        started_cluster.start_zookeeper_nodes(["zoo1"])
     finally:
-        change_balancing('first_or_random', 'random', reload=False)
+        started_cluster.start_zookeeper_nodes(["zoo1"])
+        change_balancing('round_robin', 'random', reload=False)