YQ Connector: move tests from yql to ydb (OSS)

Перенос папки с тестами на Коннектор из папки yql в папку ydb (синхронизируется с github).

1 files changed, 91 insertions, 0 deletions

diff --git a/contrib/clickhouse/src/Storages/MergeTree/LeaderElection.h b/contrib/clickhouse/src/Storages/MergeTree/LeaderElection.h
new file mode 100644
index 0000000000..2e48892563
--- /dev/null
+++ b/contrib/clickhouse/src/Storages/MergeTree/LeaderElection.h
@@ -0,0 +1,91 @@
+#pragma once
+
+#include <filesystem>
+#include <Common/logger_useful.h>
+#include <base/sort.h>
+#include <Common/ZooKeeper/ZooKeeper.h>
+#include <Common/ZooKeeper/KeeperException.h>
+#include <Core/BackgroundSchedulePool.h>
+
+namespace fs = std::filesystem;
+
+namespace zkutil
+{
+
+/** Initially was used to implement leader election algorithm described here:
+  * http://zookeeper.apache.org/doc/r3.4.5/recipes.html#sc_leaderElection
+  *
+  * But then we decided to get rid of leader election, so every replica can become leader.
+  * For now, every replica can become leader if there is no leader among replicas with old version.
+  */
+
+void checkNoOldLeaders(Poco::Logger * log, ZooKeeper & zookeeper, const String path)
+{
+    /// Previous versions (before 21.12) used to create ephemeral sequential node path/leader_election-
+    /// Replica with the lexicographically smallest node name becomes leader (before 20.6) or enables multi-leader mode (since 20.6)
+    constexpr auto persistent_multiple_leaders = "leader_election-0";   /// Less than any sequential node
+    constexpr auto suffix = " (multiple leaders Ok)";
+    constexpr auto persistent_identifier = "all (multiple leaders Ok)";
+
+    size_t num_tries = 1000;
+    while (num_tries--)
+    {
+        Strings potential_leaders;
+        Coordination::Error code = zookeeper.tryGetChildren(path, potential_leaders);
+        /// NOTE zookeeper_path/leader_election node must exist now, but maybe we will remove it in future versions.
+        if (code == Coordination::Error::ZNONODE)
+            return;
+        else if (code != Coordination::Error::ZOK)
+            throw KeeperException::fromPath(code, path);
+
+        Coordination::Requests ops;
+
+        if (potential_leaders.empty())
+        {
+            /// Ensure that no leaders appeared and enable persistent multi-leader mode
+            /// May fail with ZNOTEMPTY
+            ops.emplace_back(makeRemoveRequest(path, 0));
+            ops.emplace_back(makeCreateRequest(path, "", zkutil::CreateMode::Persistent));
+            /// May fail with ZNODEEXISTS
+            ops.emplace_back(makeCreateRequest(fs::path(path) / persistent_multiple_leaders, persistent_identifier, zkutil::CreateMode::Persistent));
+        }
+        else
+        {
+            ::sort(potential_leaders.begin(), potential_leaders.end());
+            if (potential_leaders.front() == persistent_multiple_leaders)
+                return;
+
+            /// Ensure that current leader supports multi-leader mode and make it persistent
+            auto current_leader = fs::path(path) / potential_leaders.front();
+            Coordination::Stat leader_stat;
+            String identifier;
+            if (!zookeeper.tryGet(current_leader, identifier, &leader_stat))
+            {
+                LOG_INFO(log, "LeaderElection: leader suddenly changed, will retry");
+                continue;
+            }
+
+            if (!identifier.ends_with(suffix))
+                throw Poco::Exception(fmt::format("Found leader replica ({}) with too old version (< 20.6). Stop it before upgrading", identifier));
+
+            /// Version does not matter, just check that it still exists.
+            /// May fail with ZNONODE
+            ops.emplace_back(makeCheckRequest(current_leader, leader_stat.version));
+            /// May fail with ZNODEEXISTS
+            ops.emplace_back(makeCreateRequest(fs::path(path) / persistent_multiple_leaders, persistent_identifier, zkutil::CreateMode::Persistent));
+        }
+
+        Coordination::Responses res;
+        code = zookeeper.tryMulti(ops, res);
+        if (code == Coordination::Error::ZOK)
+            return;
+        else if (code == Coordination::Error::ZNOTEMPTY || code == Coordination::Error::ZNODEEXISTS || code == Coordination::Error::ZNONODE)
+            LOG_INFO(log, "LeaderElection: leader suddenly changed or new node appeared, will retry");
+        else
+            KeeperMultiException::check(code, ops, res);
+    }
+
+    throw Poco::Exception("Cannot check that no old leaders exist");
+}
+
+}