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finished statement cache class

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sascha
2025-08-05 19:30:40 +02:00
parent 31964e55c1
commit 35fad9f47c
13 changed files with 410 additions and 74 deletions
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source/orm/sql/statement_cache.cpp
+111 -30
View File
@@ -4,35 +4,65 @@
#include "matador/sql/connection_pool.hpp"
#include <atomic>
#include <thread>
namespace matador::sql {
namespace internal {
class statement_cache_proxy final : public statement_proxy {
public:
explicit statement_cache_proxy(std::unique_ptr<statement_impl>&& stmt)
: statement_proxy(std::move(stmt)) {}
struct retry_config {
size_t max_attempts{10};
std::chrono::milliseconds initial_wait{10};
std::chrono::milliseconds max_wait{250};
};
explicit statement_cache_proxy(std::unique_ptr<statement_impl>&& stmt, connection_pool &pool, const size_t connection_id)
: statement_proxy(std::move(stmt))
, pool_(pool)
, connection_id_(connection_id) {}
utils::result<size_t, utils::error> execute(interface::parameter_binder& bindings) override {
if (!try_lock()) {
return utils::failure(utils::error{
error_code::STATEMENT_LOCKED,
"Failed to execute statement because it is already in use"
});
}
auto result = try_with_retry([this, &bindings]() -> utils::result<size_t, utils::error> {
if (!try_lock()) {
return utils::failure(utils::error{
error_code::STATEMENT_LOCKED,
"Failed to execute statement because it is already in use"
});
}
auto guard = statement_guard(*this);
return statement_->execute(bindings);
auto guard = statement_guard(*this);
if (auto conn = pool_.acquire(connection_id_); !conn.valid()) {
return utils::failure(utils::error{
error_code::EXECUTE_FAILED,
"Failed to execute statement because couldn't lock connection"
});
}
return statement_->execute(bindings);
});
return result;
}
utils::result<std::unique_ptr<query_result_impl>, utils::error> fetch(interface::parameter_binder& bindings) override {
if (!try_lock()) {
return utils::failure(utils::error{
error_code::STATEMENT_LOCKED,
"Failed to execute statement because it is already in use"
});
}
auto guard = statement_guard(*this);
return statement_->fetch(bindings);
utils::result<std::unique_ptr<query_result_impl>, utils::error> fetch(interface::parameter_binder& bindings) override {
auto result = try_with_retry([this, &bindings]() -> utils::result<std::unique_ptr<query_result_impl>, utils::error> {
if (!try_lock()) {
return utils::failure(utils::error{
error_code::STATEMENT_LOCKED,
"Failed to execute statement because it is already in use"
});
}
auto guard = statement_guard(*this);
if (const auto conn = pool_.acquire(connection_id_); !conn.valid()) {
return utils::failure(utils::error{
error_code::EXECUTE_FAILED,
"Failed to execute statement because couldn't lock connection"
});
}
return statement_->fetch(bindings);
});
return result;
}
protected:
@@ -41,6 +71,28 @@ protected:
return locked_.compare_exchange_strong(expected, true);
}
template<typename Func>
[[nodiscard]] auto try_with_retry(Func &&func) -> decltype(func()) {
auto current_wait = config_.initial_wait;
for (size_t attempt = 0; attempt < config_.max_attempts; ++attempt) {
if (auto result = func(); result.is_ok() ||
result.err().ec() != error_code::STATEMENT_LOCKED) {
return result;
}
if (attempt + 1 < config_.max_attempts) {
std::this_thread::sleep_for(current_wait);
current_wait = std::min(current_wait * 2, config_.max_wait);
}
}
return utils::failure(utils::error{
error_code::STATEMENT_LOCKED,
"Failed to execute statement because it is already in use"
});
}
void unlock() {
locked_.store(false);
}
@@ -56,6 +108,9 @@ private:
private:
std::atomic_bool locked_{false};
connection_pool &pool_;
size_t connection_id_{};
retry_config config_{};
};
}
@@ -68,35 +123,46 @@ utils::result<statement, utils::error> statement_cache::acquire(const query_cont
std::unique_lock lock(mutex_);
// hash statement
const auto key = std::hash<std::string>{}(ctx.sql);
const auto now = std::chrono::steady_clock::now();
// Found in cache. Move it to of the LRU list
if (const auto it = cache_map_.find(key); it != cache_map_.end()) {
usage_list_.splice(usage_list_.begin(), usage_list_, it->second.second);
return utils::ok(it->second.first);
usage_list_.splice(usage_list_.begin(), usage_list_, it->second.position);
it->second.last_access = now;
push(statement_cache_event::Type::Accessed, ctx.sql);
return utils::ok(it->second.stmt);
}
// Prepare a new statement
// acquire pool connection
const auto conn = pool_.acquire();
auto result = conn->perform_prepare(ctx);
if (!result) {
return utils::failure(utils::error{error_code::PREPARE_FAILED, std::string("Failed to prepare")});
size_t id{};
std::unique_ptr<statement_impl> stmt;
{
const auto conn = pool_.acquire();
auto result = conn->perform_prepare(ctx);
if (!result) {
return utils::failure(utils::error{error_code::PREPARE_FAILED, std::string("Failed to prepare")});
}
id = conn.id().value();
stmt = result.release();
}
// If cache max size reached ensure space
if (cache_map_.size() >= max_size_) {
const auto& key_to_remove = usage_list_.back();
cache_map_.erase(key_to_remove);
usage_list_.pop_back();
push(statement_cache_event::Type::Evicted, ctx.sql);
}
usage_list_.push_front(key);
const auto it = cache_map_.insert({
key,
std::make_pair(statement{
std::make_shared<internal::statement_cache_proxy>(result.release())},
usage_list_.begin())
{statement{
std::make_shared<internal::statement_cache_proxy>(std::move(stmt), pool_, id)},
std::chrono::steady_clock::now(),
usage_list_.begin()}
}).first;
push(statement_cache_event::Type::Added, ctx.sql);
return utils::ok(it->second.first);
return utils::ok(it->second.stmt);
}
size_t statement_cache::size() const {
@@ -109,4 +175,19 @@ size_t statement_cache::capacity() const {
bool statement_cache::empty() const {
return cache_map_.empty();
}
void statement_cache::subscribe(statement_cache_observer_interface &observer) {
observers_.push_back(&observer);
}
void statement_cache::push(statement_cache_event::Type type, const std::string &sql) const {
using Clock = std::chrono::steady_clock;
const auto ts = Clock::now();
const statement_cache_event evt{type, sql, ts};
for (auto& obs : observers_) {
if (obs) {
obs->on_event(evt);
}
}
}
}