Merge pull request ClickHouse#52195 from Algunenano/happy_grandma

Create ZK ancestors optimistically

src/Common/ZooKeeper/ZooKeeper.cpp

@@ -3,8 +3,10 @@
 #include "KeeperException.h"
 #include "TestKeeper.h"
 
-#include <functional>
 #include <filesystem>
+#include <functional>
+#include <ranges>
+#include <vector>
 
 #include <Common/ZooKeeper/Types.h>
 #include <Common/ZooKeeper/ZooKeeperCommon.h>
@@ -350,15 +352,35 @@ void ZooKeeper::createIfNotExists(const std::string & path, const std::string &
 
 void ZooKeeper::createAncestors(const std::string & path)
 {
- size_t pos = 1;
+ std::string data;
+ std::string path_created; // Ignored
+ std::vector<std::string> pending_nodes;
+
+ size_t last_pos = path.rfind('/');
+ if (last_pos == std::string::npos || last_pos == 0)
+ return;
+ std::string current_node = path.substr(0, last_pos);
+
  while (true)
  {
- pos = path.find('/', pos);
- if (pos == std::string::npos)
+ Coordination::Error code = createImpl(current_node, data, CreateMode::Persistent, path_created);
+ if (code == Coordination::Error::ZNONODE)
+ {
+ /// The parent node doesn't exist. Save the current node and try with the parent
+ last_pos = current_node.rfind('/');
+ if (last_pos == std::string::npos || last_pos == 0)
+ throw KeeperException(code, path);
+ pending_nodes.emplace_back(std::move(current_node));
+ current_node = path.substr(0, last_pos);
+ }
+ else if (code == Coordination::Error::ZOK || code == Coordination::Error::ZNODEEXISTS)
  break;
- createIfNotExists(path.substr(0, pos), "");
- ++pos;
+ else
+  throw KeeperException(code, path);
  }
+
+ for (const std::string & pending : pending_nodes | std::views::reverse)
+ createIfNotExists(pending, data);
 }
 
 void ZooKeeper::checkExistsAndGetCreateAncestorsOps(const std::string & path, Coordination::Requests & requests)

src/Storages/StorageReplicatedMergeTree.cpp

@@ -9178,8 +9178,7 @@ std::optional<ZeroCopyLock> StorageReplicatedMergeTree::tryCreateZeroCopyExclusi
  String zc_zookeeper_path = *getZeroCopyPartPath(part_name, disk);
 
  /// Just recursively create ancestors for lock
- zookeeper->createAncestors(zc_zookeeper_path);
- zookeeper->createIfNotExists(zc_zookeeper_path, "");
+ zookeeper->createAncestors(zc_zookeeper_path + "/");
 
  /// Create actual lock
  ZeroCopyLock lock(zookeeper, zc_zookeeper_path, replica_name);