From 2c56d53ca3d86906b9f13b881d4d6564df480d20 Mon Sep 17 00:00:00 2001
From: arudenko02 <arudenko02@userver.tech>
Date: Mon, 27 Jan 2025 15:46:23 +0300
Subject: [PATCH] refactor postgresql: don't read settings twice

Relates: <HIDDEN_URL>
commit_hash:5ffb8e27f6d37855d446c5aeb8a3ab9ed5c11122
---
 .../src/storages/postgres/detail/pool.cpp     | 25 ++++++++++---------
 .../src/storages/postgres/detail/pool.hpp     |  4 +--
 2 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/postgresql/src/storages/postgres/detail/pool.cpp b/postgresql/src/storages/postgres/detail/pool.cpp
index 9c6722938920..9fc4cdc2cc73 100644
--- a/postgresql/src/storages/postgres/detail/pool.cpp
+++ b/postgresql/src/storages/postgres/detail/pool.cpp
@@ -178,12 +178,14 @@ void ConnectionPool::Init(InitMode mode) {
 
     std::vector<engine::TaskWithResult<bool>> tasks;
     tasks.reserve(settings->min_size);
+    const auto conn_settings = conn_settings_.ReadCopy();
     for (std::size_t i = 0; i < settings->min_size; ++i) {
-        tasks.push_back(Connect(engine::SemaphoreLock{size_semaphore_, std::try_to_lock}));
+        tasks.push_back(
+            Connect(engine::SemaphoreLock{size_semaphore_, std::try_to_lock}, ConnectionSettings{conn_settings})
+        );
     }
 
-    auto conn_settings = conn_settings_.Read();
-    if (conn_settings->user_types == ConnectionSettings::kUserTypesEnforced) {
+    if (conn_settings.user_types == ConnectionSettings::kUserTypesEnforced) {
         CheckUserTypes();
     }
 
@@ -388,16 +390,16 @@ dynamic_config::Source ConnectionPool::GetConfigSource() const { return config_s
 
 const Dsn& ConnectionPool::GetDsn() const { return dsn_; }
 
-engine::TaskWithResult<bool> ConnectionPool::Connect(engine::SemaphoreLock lock) {
-    return engine::AsyncNoSpan([this, size_lock = std::move(lock)]() mutable {
+engine::TaskWithResult<bool> ConnectionPool::Connect(engine::SemaphoreLock lock, ConnectionSettings&& conn_settings) {
+    return engine::AsyncNoSpan([this, size_lock = std::move(lock), conn_settings = std::move(conn_settings)]() mutable {
         if (!size_lock) {
             size_lock = engine::SemaphoreLock{size_semaphore_, kConnectingTimeout};
         }
-        return DoConnect(std::move(size_lock));
+        return DoConnect(std::move(size_lock), std::move(conn_settings));
     });
 }
 
-bool ConnectionPool::DoConnect(engine::SemaphoreLock size_lock) {
+bool ConnectionPool::DoConnect(engine::SemaphoreLock size_lock, ConnectionSettings&& conn_settings) {
     if (!size_lock) return false;
     LOG_TRACE() << "Creating PostgreSQL connection, current pool size: " << size_semaphore_.UsedApprox();
     engine::SemaphoreLock connecting_lock{connecting_semaphore_, kConnectingTimeout};
@@ -406,7 +408,6 @@ bool ConnectionPool::DoConnect(engine::SemaphoreLock size_lock) {
         return false;
     }
     const uint32_t conn_id = ++stats_.connection.open_total;
-    auto conn_settings = conn_settings_.Read();
     std::unique_ptr<Connection> connection;
     Stopwatch st{stats_.connection_percentile};
     try {
@@ -416,7 +417,7 @@ bool ConnectionPool::DoConnect(engine::SemaphoreLock size_lock) {
             bg_task_processor_,
             close_task_storage_,
             conn_id,
-            *conn_settings,
+            std::move(conn_settings),
             default_cmd_ctls_,
             testsuite_pg_ctl_,
             ei_settings_,
@@ -451,13 +452,13 @@ bool ConnectionPool::DoConnect(engine::SemaphoreLock size_lock) {
 }
 
 void ConnectionPool::TryCreateConnectionAsync() {
-    auto conn_settings = conn_settings_.Read();
+    auto conn_settings = conn_settings_.ReadCopy();
     // Checking errors is more expensive than incrementing an atomic, so we
     // check it only if we can start a new connection.
-    if (recent_conn_errors_.GetStatsForPeriod(kRecentErrorPeriod, true) < conn_settings->recent_errors_threshold) {
+    if (recent_conn_errors_.GetStatsForPeriod(kRecentErrorPeriod, true) < conn_settings.recent_errors_threshold) {
         engine::SemaphoreLock size_lock{size_semaphore_, std::try_to_lock};
         if (size_lock || connect_task_storage_.ActiveTasksApprox() <= kPendingConnectsMax) {
-            connect_task_storage_.Detach(Connect(std::move(size_lock)));
+            connect_task_storage_.Detach(Connect(std::move(size_lock), std::move(conn_settings)));
         }
     } else {
         LOG_DEBUG() << "Too many connection errors in recent period";
diff --git a/postgresql/src/storages/postgres/detail/pool.hpp b/postgresql/src/storages/postgres/detail/pool.hpp
index ab352b60dc41..1d8bc0e737ae 100644
--- a/postgresql/src/storages/postgres/detail/pool.hpp
+++ b/postgresql/src/storages/postgres/detail/pool.hpp
@@ -110,8 +110,8 @@ class ConnectionPool : public std::enable_shared_from_this<ConnectionPool> {
 
     TimeoutDuration GetExecuteTimeout(OptionalCommandControl) const;
 
-    [[nodiscard]] engine::TaskWithResult<bool> Connect(engine::SemaphoreLock);
-    bool DoConnect(engine::SemaphoreLock);
+    [[nodiscard]] engine::TaskWithResult<bool> Connect(engine::SemaphoreLock, ConnectionSettings&&);
+    bool DoConnect(engine::SemaphoreLock, ConnectionSettings&&);
 
     void TryCreateConnectionAsync();
     void CheckMinPoolSizeUnderflow();