Rewriting implementation of LIVE VIEW no users thread.

This commit is contained in:
Vitaliy Zakaznikov 2019-08-24 21:40:24 -04:00
parent f959c29be6
commit 62988800e6
4 changed files with 63 additions and 60 deletions

View File

@ -18,10 +18,13 @@ using NonBlockingResult = std::pair<Block, bool>;
public:
~LiveViewBlockInputStream() override
{
/// Start storage no users thread
/// if we are the last active user
if (!storage->is_dropped && blocks_ptr.use_count() < 3)
storage->startNoUsersThread(temporary_live_view_timeout_sec);
/// Wake up no users thread
{
std::cerr << "DEBUG: live view block input stream ... send wake up thread\n";
std::lock_guard lock(storage->no_users_thread_mutex);
storage->no_users_thread_wakeup = true;
storage->no_users_thread_condition.notify_one();
}
}
LiveViewBlockInputStream(std::shared_ptr<StorageLiveView> storage_,
@ -29,9 +32,12 @@ public:
std::shared_ptr<BlocksMetadataPtr> blocks_metadata_ptr_,
std::shared_ptr<bool> active_ptr_,
const bool has_limit_, const UInt64 limit_,
const UInt64 heartbeat_interval_sec_,
const UInt64 temporary_live_view_timeout_sec_)
: storage(std::move(storage_)), blocks_ptr(std::move(blocks_ptr_)), blocks_metadata_ptr(std::move(blocks_metadata_ptr_)), active_ptr(std::move(active_ptr_)), has_limit(has_limit_), limit(limit_), heartbeat_interval_usec(heartbeat_interval_sec_ * 1000000), temporary_live_view_timeout_sec(temporary_live_view_timeout_sec_)
const UInt64 heartbeat_interval_sec_)
: storage(std::move(storage_)), blocks_ptr(std::move(blocks_ptr_)),
blocks_metadata_ptr(std::move(blocks_metadata_ptr_)),
active_ptr(std::move(active_ptr_)),
has_limit(has_limit_), limit(limit_),
heartbeat_interval_usec(heartbeat_interval_sec_ * 1000000)
{
/// grab active pointer
active = active_ptr.lock();
@ -200,7 +206,6 @@ private:
Int64 num_updates = -1;
bool end_of_blocks = false;
UInt64 heartbeat_interval_usec;
UInt64 temporary_live_view_timeout_sec;
UInt64 last_event_timestamp_usec = 0;
Poco::Timestamp timestamp;
};

View File

@ -37,10 +37,12 @@ using NonBlockingResult = std::pair<Block, bool>;
public:
~LiveViewEventsBlockInputStream() override
{
/// Start storage no users thread
/// if we are the last active user
if (!storage->is_dropped && blocks_ptr.use_count() < 3)
storage->startNoUsersThread(temporary_live_view_timeout_sec);
/// Wake up no users thread
{
std::lock_guard lock(storage->no_users_thread_mutex);
storage->no_users_thread_wakeup = true;
storage->no_users_thread_condition.notify_one();
}
}
/// length default -2 because we want LIMIT to specify number of updates so that LIMIT 1 waits for 1 update
/// and LIMIT 0 just returns data without waiting for any updates
@ -49,9 +51,12 @@ public:
std::shared_ptr<BlocksMetadataPtr> blocks_metadata_ptr_,
std::shared_ptr<bool> active_ptr_,
const bool has_limit_, const UInt64 limit_,
const UInt64 heartbeat_interval_sec_,
const UInt64 temporary_live_view_timeout_sec_)
: storage(std::move(storage_)), blocks_ptr(std::move(blocks_ptr_)), blocks_metadata_ptr(std::move(blocks_metadata_ptr_)), active_ptr(std::move(active_ptr_)), has_limit(has_limit_), limit(limit_), heartbeat_interval_usec(heartbeat_interval_sec_ * 1000000), temporary_live_view_timeout_sec(temporary_live_view_timeout_sec_)
const UInt64 heartbeat_interval_sec_)
: storage(std::move(storage_)), blocks_ptr(std::move(blocks_ptr_)),
blocks_metadata_ptr(std::move(blocks_metadata_ptr_)),
active_ptr(std::move(active_ptr_)), has_limit(has_limit_),
limit(limit_),
heartbeat_interval_usec(heartbeat_interval_sec_ * 1000000)
{
/// grab active pointer
active = active_ptr.lock();
@ -236,7 +241,6 @@ private:
Int64 num_updates = -1;
bool end_of_blocks = false;
UInt64 heartbeat_interval_usec;
UInt64 temporary_live_view_timeout_sec;
UInt64 last_event_timestamp_usec = 0;
Poco::Timestamp timestamp;
};

View File

@ -363,45 +363,49 @@ void StorageLiveView::checkTableCanBeDropped() const
}
}
void StorageLiveView::noUsersThread(const UInt64 & timeout)
void StorageLiveView::noUsersThread(std::shared_ptr<StorageLiveView> storage, const UInt64 & timeout)
{
if (shutdown_called)
return;
bool drop_table = false;
if (storage->shutdown_called || storage->is_dropped)
return;
{
while (1)
{
std::unique_lock lock(no_users_thread_mutex);
if (!no_users_thread_condition.wait_for(lock, std::chrono::seconds(timeout), [&] { return no_users_thread_wakeup; }))
std::unique_lock lock(storage->no_users_thread_mutex);
if(!storage->no_users_thread_condition.wait_for(lock, std::chrono::seconds(timeout), [&] { return storage->no_users_thread_wakeup; }))
{
no_users_thread_wakeup = false;
if (shutdown_called)
storage->no_users_thread_wakeup = false;
if (storage->shutdown_called || storage->is_dropped)
return;
if (hasUsers())
return;
if (!global_context.getDependencies(database_name, table_name).empty())
if (storage->hasUsers())
continue;
if (!storage->global_context.getDependencies(storage->database_name, storage->table_name).empty())
continue;
drop_table = true;
}
else {
storage->no_users_thread_wakeup = false;
continue;
}
break;
}
}
if (drop_table)
{
if (global_context.tryGetTable(database_name, table_name))
if (storage->global_context.tryGetTable(storage->database_name, storage->table_name))
{
try
{
/// We create and execute `drop` query for this table
auto drop_query = std::make_shared<ASTDropQuery>();
drop_query->database = database_name;
drop_query->table = table_name;
drop_query->database = storage->database_name;
drop_query->table = storage->table_name;
drop_query->kind = ASTDropQuery::Kind::Drop;
ASTPtr ast_drop_query = drop_query;
InterpreterDropQuery drop_interpreter(ast_drop_query, global_context);
InterpreterDropQuery drop_interpreter(ast_drop_query, storage->global_context);
drop_interpreter.execute();
}
catch (...)
@ -413,13 +417,6 @@ void StorageLiveView::noUsersThread(const UInt64 & timeout)
void StorageLiveView::startNoUsersThread(const UInt64 & timeout)
{
bool expected = false;
if (!start_no_users_thread_called.compare_exchange_strong(expected, true))
return;
if (is_dropped)
return;
if (is_temporary)
{
if (no_users_thread.joinable())
@ -435,10 +432,9 @@ void StorageLiveView::startNoUsersThread(const UInt64 & timeout)
std::lock_guard lock(no_users_thread_mutex);
no_users_thread_wakeup = false;
}
if (!is_dropped)
no_users_thread = std::thread(&StorageLiveView::noUsersThread, this, timeout);
no_users_thread = std::thread(&StorageLiveView::noUsersThread,
std::static_pointer_cast<StorageLiveView>(shared_from_this()), timeout);
}
start_no_users_thread_called = false;
}
void StorageLiveView::startup()
@ -454,19 +450,19 @@ void StorageLiveView::shutdown()
if (no_users_thread.joinable())
{
std::lock_guard lock(no_users_thread_mutex);
no_users_thread_wakeup = true;
no_users_thread_condition.notify_one();
/// Must detach the no users thread
/// as we can't join it as it will result
/// in a deadlock
no_users_thread.detach(); /// TODO Not viable at all.
{
std::lock_guard lock(no_users_thread_mutex);
no_users_thread_wakeup = true;
no_users_thread_condition.notify_one();
}
}
}
StorageLiveView::~StorageLiveView()
{
shutdown();
if (no_users_thread.joinable())
no_users_thread.detach();
}
void StorageLiveView::drop()
@ -532,8 +528,7 @@ BlockInputStreams StorageLiveView::watch(
if (query.is_watch_events)
{
auto reader = std::make_shared<LiveViewEventsBlockInputStream>(std::static_pointer_cast<StorageLiveView>(shared_from_this()), blocks_ptr, blocks_metadata_ptr, active_ptr, has_limit, limit, context.getSettingsRef().live_view_heartbeat_interval.totalSeconds(),
context.getSettingsRef().temporary_live_view_timeout.totalSeconds());
auto reader = std::make_shared<LiveViewEventsBlockInputStream>(std::static_pointer_cast<StorageLiveView>(shared_from_this()), blocks_ptr, blocks_metadata_ptr, active_ptr, has_limit, limit, context.getSettingsRef().live_view_heartbeat_interval.totalSeconds());
if (no_users_thread.joinable())
{
@ -557,8 +552,7 @@ BlockInputStreams StorageLiveView::watch(
}
else
{
auto reader = std::make_shared<LiveViewBlockInputStream>(std::static_pointer_cast<StorageLiveView>(shared_from_this()), blocks_ptr, blocks_metadata_ptr, active_ptr, has_limit, limit, context.getSettingsRef().live_view_heartbeat_interval.totalSeconds(),
context.getSettingsRef().temporary_live_view_timeout.totalSeconds());
auto reader = std::make_shared<LiveViewBlockInputStream>(std::static_pointer_cast<StorageLiveView>(shared_from_this()), blocks_ptr, blocks_metadata_ptr, active_ptr, has_limit, limit, context.getSettingsRef().live_view_heartbeat_interval.totalSeconds());
if (no_users_thread.joinable())
{

View File

@ -71,11 +71,9 @@ public:
{
return active_ptr.use_count() > 1;
}
/// Background thread for temporary tables
/// which drops this table if there are no users
void startNoUsersThread(const UInt64 & timeout);
/// No users thread mutex, predicate and wake up condition
std::mutex no_users_thread_mutex;
bool no_users_thread_wakeup{false};
bool no_users_thread_wakeup = false;
std::condition_variable no_users_thread_condition;
/// Get blocks hash
/// must be called with mutex locked
@ -149,7 +147,7 @@ private:
String database_name;
ASTPtr inner_query;
Context & global_context;
bool is_temporary {false};
bool is_temporary = false;
mutable Block sample_block;
/// Mutex for the blocks and ready condition
@ -166,10 +164,12 @@ private:
std::shared_ptr<BlocksMetadataPtr> blocks_metadata_ptr;
BlocksPtrs mergeable_blocks;
void noUsersThread(const UInt64 & timeout);
/// Background thread for temporary tables
/// which drops this table if there are no users
void startNoUsersThread(const UInt64 & timeout);
static void noUsersThread(std::shared_ptr<StorageLiveView> storage, const UInt64 & timeout);
std::thread no_users_thread;
std::atomic<bool> shutdown_called{false};
std::atomic<bool> start_no_users_thread_called{false};
std::atomic<bool> shutdown_called = false;
UInt64 temporary_live_view_timeout;
StorageLiveView(