Working on adding AUTO REFRESH to LIVE VIEW tables.

src/Core/Defines.h

@@ -36,6 +36,7 @@
 #define DEFAULT_MERGE_BLOCK_SIZE 8192
 
 #define DEFAULT_TEMPORARY_LIVE_VIEW_TIMEOUT_SEC 5
+#define DEFAULT_AUTO_REFRESH_LIVE_VIEW_INTERVAL_SEC 300
 #define SHOW_CHARS_ON_SYNTAX_ERROR ptrdiff_t(160)
 #define DEFAULT_LIVE_VIEW_HEARTBEAT_INTERVAL_SEC 15
 #define DBMS_DEFAULT_DISTRIBUTED_CONNECTIONS_POOL_SIZE 1024

src/Core/Settings.h

@@ -406,6 +406,7 @@ struct Settings : public SettingsCollection<Settings>
     M(SettingBool, validate_polygons, true, "Throw exception if polygon is invalid in function pointInPolygon (e.g. self-tangent, self-intersecting). If the setting is false, the function will accept invalid polygons but may silently return wrong result.", 0) \
     M(SettingUInt64, max_parser_depth, 1000, "Maximum parser depth.", 0) \
     M(SettingSeconds, temporary_live_view_timeout, DEFAULT_TEMPORARY_LIVE_VIEW_TIMEOUT_SEC, "Timeout after which temporary live view is deleted.", 0) \
+    M(SettingSeconds, auto_refresh_live_view_interval, DEFAULT_AUTO_REFRESH_LIVE_VIEW_INTERVAL_SEC, "The interval in seconds after which auto refreshed live view is refreshed.", 0) \
     M(SettingBool, transform_null_in, false, "If enabled, NULL values will be matched with 'IN' operator as if they are considered equal.", 0) \
     M(SettingBool, allow_nondeterministic_mutations, false, "Allow non-deterministic functions in ALTER UPDATE/ALTER DELETE statements", 0) \
     M(SettingSeconds, lock_acquire_timeout, DBMS_DEFAULT_LOCK_ACQUIRE_TIMEOUT_SEC, "How long locking request should wait before failing", 0) \

src/Parsers/ASTCreateQuery.cpp

@@ -234,9 +234,16 @@ void ASTCreateQuery::formatQueryImpl(const FormatSettings & settings, FormatStat
                 << (if_not_exists ? "IF NOT EXISTS " : "")
             << (settings.hilite ? hilite_none : "")
             << (!database.empty() ? backQuoteIfNeed(database) + "." : "") << backQuoteIfNeed(table);
-        if (live_view_timeout)
+        if (live_view_timeout || live_view_auto_refresh)
-            settings.ostr << (settings.hilite ? hilite_keyword : "") << " WITH TIMEOUT " << (settings.hilite ? hilite_none : "")
+        {
-                          << *live_view_timeout;
+            settings.ostr << (settings.hilite ? hilite_keyword : "") << " WITH " << (settings.hilite ? hilite_none : "");
+            if (live_view_timeout)
+                settings.ostr << (settings.hilite ? hilite_keyword : "") << "TIMEOUT " << (settings.hilite ? hilite_none : "")
+                    << *live_view_timeout;
+            if (live_view_auto_refresh)
+                settings.ostr << (live_view_timeout ? ", " : "")  << (settings.hilite ? hilite_keyword : "") << "AUTO REFRESH " << (settings.hilite ? hilite_none : "")
+                    << *live_view_auto_refresh;
+        }
         formatOnCluster(settings);
     }
     else

src/Parsers/ASTCreateQuery.h

@@ -73,6 +73,7 @@ public:
     ASTSelectWithUnionQuery * select = nullptr;
     ASTDictionary * dictionary = nullptr; /// dictionary definition (layout, primary key, etc.)
     std::optional<UInt64> live_view_timeout;    /// For CREATE LIVE VIEW ... WITH TIMEOUT ...
+    std::optional<UInt64> live_view_auto_refresh;    /// For CREATE LIVE VIEW ... WITH AUTO REFRESH ...
 
     /** Get the text that identifies this element. */
     String getID(char delim) const override { return (attach ? "AttachQuery" : "CreateQuery") + (delim + database) + delim + table; }

src/Parsers/ParserCreateQuery.cpp

@@ -510,6 +510,7 @@ bool ParserCreateLiveViewQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & e
     ASTPtr as_table;
     ASTPtr select;
     ASTPtr live_view_timeout;
+    ASTPtr live_view_auto_refresh;
 
     String cluster_str;
     bool attach = false;
@@ -542,10 +543,27 @@ bool ParserCreateLiveViewQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & e
             return false;
     }
 
-    if (ParserKeyword{"WITH TIMEOUT"}.ignore(pos, expected))
+    if (ParserKeyword{"WITH"}.ignore(pos, expected))
     {
-        if (!ParserNumber{}.parse(pos, live_view_timeout, expected))
+        do
-            live_view_timeout = std::make_shared<ASTLiteral>(static_cast<UInt64>(DEFAULT_TEMPORARY_LIVE_VIEW_TIMEOUT_SEC));
+        {
+            if (!live_view_timeout && ParserKeyword{"TIMEOUT"}.ignore(pos, expected))
+            {
+                if (!ParserNumber{}.parse(pos, live_view_timeout, expected))
+                    live_view_timeout = std::make_shared<ASTLiteral>(static_cast<UInt64>(DEFAULT_TEMPORARY_LIVE_VIEW_TIMEOUT_SEC));
+            }
+            else if (!live_view_auto_refresh && ParserKeyword{"AUTO REFRESH"}.ignore(pos, expected))
+            {
+                if (!ParserNumber{}.parse(pos, live_view_auto_refresh, expected))
+                    live_view_auto_refresh = std::make_shared<ASTLiteral>(static_cast<UInt64>(DEFAULT_AUTO_REFRESH_LIVE_VIEW_INTERVAL_SEC));
+            }
+            else
+                return false;
+        }
+        while ((!live_view_timeout || !live_view_auto_refresh) && ParserToken{TokenType::Comma}.ignore(pos, expected));
+
+        if (!live_view_timeout && !live_view_auto_refresh)
+            return false;
     }
 
     if (ParserKeyword{"ON"}.ignore(pos, expected))
@@ -608,6 +626,8 @@ bool ParserCreateLiveViewQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & e
 
     if (live_view_timeout)
         query->live_view_timeout.emplace(live_view_timeout->as<ASTLiteral &>().value.safeGet<UInt64>());
+    if (live_view_auto_refresh)
+        query->live_view_auto_refresh.emplace(live_view_auto_refresh->as<ASTLiteral &>().value.safeGet<UInt64>());
 
     return true;
 }

src/Parsers/ParserCreateQuery.h

@@ -312,7 +312,7 @@ protected:
     bool parseImpl(Pos & pos, ASTPtr & node, Expected & expected) override;
 };
 
-/// CREATE|ATTACH LIVE VIEW [IF NOT EXISTS] [db.]name [TO [db.]name] AS SELECT ...
+/// CREATE|ATTACH LIVE VIEW [IF NOT EXISTS] [db.]name [TO [db.]name] [WITH {TIMEOUT | AUTO REFRESH} [num]} [,...]] AS SELECT ...
 class ParserCreateLiveViewQuery : public IParserBase
 {
 protected:

src/Storages/LiveView/Events.h

@@ -0,0 +1,14 @@
+#pragma once
+
+namespace DB
+{
+    /// events processed by the events thread
+    enum LiveViewEvent
+    {
+        NONE = 0,
+        LAST_USER = 1,
+        NEW_USER = 2,
+        NEW_BLOCKS = 4,
+        SHUTDOWN = 8
+    };
+}

src/Storages/LiveView/LiveViewBlockInputStream.h

@@ -1,13 +1,13 @@
 #pragma once
 
 #include <DataStreams/IBlockInputStream.h>
-
+#include <Storages/LiveView/Events.h>
 
 namespace DB
 {
 
 /** Implements LIVE VIEW table WATCH input stream.
- *  Keeps stream alive by outputing blocks with no rows
+ *  Keeps stream alive by outputting blocks with no rows
  *  based on period specified by the heartbeat interval.
  */
 class LiveViewBlockInputStream : public IBlockInputStream
@@ -18,10 +18,9 @@ using NonBlockingResult = std::pair<Block, bool>;
 public:
     ~LiveViewBlockInputStream() override
     {
-        /// Start storage no users thread
+        /// Wakeup storage events thread if we are the last active user
-        /// if we are the last active user
         if (!storage->is_dropped && blocks_ptr.use_count() < 3)
-            storage->startNoUsersThread(temporary_live_view_timeout_sec);
+            storage->wakeupEventsThread(LiveViewEvent::LAST_USER);
     }
 
     LiveViewBlockInputStream(std::shared_ptr<StorageLiveView> storage_,
@@ -29,14 +28,12 @@ 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 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),
+          heartbeat_interval_usec(heartbeat_interval_sec_ * 1000000)
-          temporary_live_view_timeout_sec(temporary_live_view_timeout_sec_)
     {
         /// grab active pointer
         active = active_ptr.lock();
@@ -205,7 +202,6 @@ 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;
 };
 

src/Storages/LiveView/LiveViewBlockOutputStream.h

@@ -45,8 +45,8 @@ public:
 
             (*storage.blocks_ptr) = new_blocks;
             (*storage.blocks_metadata_ptr) = new_blocks_metadata;
-
             storage.condition.notify_all();
+            storage.wakeupEventsThread(LiveViewEvent::NEW_BLOCKS);
         }
 
         new_blocks.reset();

src/Storages/LiveView/LiveViewEventsBlockInputStream.h

@@ -19,13 +19,13 @@ limitations under the License. */
 #include <DataStreams/OneBlockInputStream.h>
 #include <DataStreams/IBlockInputStream.h>
 #include <Storages/LiveView/StorageLiveView.h>
-
+#include <Storages/LiveView/Events.h>
 
 namespace DB
 {
 
 /** Implements LIVE VIEW table WATCH EVENTS input stream.
- *  Keeps stream alive by outputing blocks with no rows
+ *  Keeps stream alive by outputting blocks with no rows
  *  based on period specified by the heartbeat interval.
  */
 class LiveViewEventsBlockInputStream : public IBlockInputStream
@@ -36,10 +36,9 @@ using NonBlockingResult = std::pair<Block, bool>;
 public:
     ~LiveViewEventsBlockInputStream() override
     {
-        /// Start storage no users thread
+        /// Wakeup storage events thread if we are the last active user
-        /// if we are the last active user
         if (!storage->is_dropped && blocks_ptr.use_count() < 3)
-            storage->startNoUsersThread(temporary_live_view_timeout_sec);
+            storage->wakeupEventsThread(LiveViewEvent::LAST_USER);
     }
     /// 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
@@ -48,14 +47,12 @@ 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 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),
+          heartbeat_interval_usec(heartbeat_interval_sec_ * 1000000)
-          temporary_live_view_timeout_sec(temporary_live_view_timeout_sec_)
     {
         /// grab active pointer
         active = active_ptr.lock();
@@ -236,7 +233,6 @@ 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;
 };

src/Storages/LiveView/StorageLiveView.cpp

@@ -271,6 +271,11 @@ StorageLiveView::StorageLiveView(
         is_temporary = true;
         temporary_live_view_timeout = *query.live_view_timeout;
     }
+    if (query.live_view_auto_refresh)
+    {
+        is_auto_refreshed = true;
+        auto_refresh_live_view_interval = *query.live_view_auto_refresh;
+    }
 
     blocks_ptr = std::make_shared<BlocksPtr>();
     blocks_metadata_ptr = std::make_shared<BlocksMetadataPtr>();
@@ -371,6 +376,7 @@ bool StorageLiveView::getNewBlocks()
             (*blocks_ptr) = new_blocks;
             (*blocks_metadata_ptr) = new_blocks_metadata;
             updated = true;
+            wakeupEventsThread(LiveViewEvent::NEW_BLOCKS);
         }
     }
     return updated;
@@ -387,34 +393,44 @@ void StorageLiveView::checkTableCanBeDropped() const
     }
 }
 
-void StorageLiveView::noUsersThread(std::shared_ptr<StorageLiveView> storage, const UInt64 & timeout)
+void StorageLiveView::eventsThread(std::shared_ptr<StorageLiveView> storage)
 {
-    bool drop_table = false;
-
     if (storage->shutdown_called)
         return;
 
     auto table_id = storage->getStorageID();
+    UInt64 next_event_timeout = 15;
+    unsigned int event = 0;
+    UInt64 event_timestamp_usec = 0;
+
+    while (true)
     {
-        while (true)
+        std::unique_lock lock(storage->events_thread_wakeup_mutex);
+        if (storage->events_thread_condition.wait_for(lock, std::chrono::seconds(next_event_timeout), [&] { return storage->events_thread_wakeup; }))
         {
-            std::unique_lock lock(storage->no_users_thread_wakeup_mutex);
+            storage->events_thread_wakeup = false;
-            if (!storage->no_users_thread_condition.wait_for(lock, std::chrono::seconds(timeout), [&] { return storage->no_users_thread_wakeup; }))
+            event = storage->events_thread_event;
-            {
+            event_timestamp_usec = storage->events_thread_event_timestamp_usec;
-                storage->no_users_thread_wakeup = false;
+            storage->events_thread_event = 0;
-                if (storage->shutdown_called)
+            storage->events_thread_event_timestamp_usec = 0;
-                    return;
+            std::cerr << "!!!: eventsThread got EVENT " << event << "\n";
-                if (storage->hasUsers())
+
-                    return;
+            if (storage->shutdown_called || event == LiveViewEvent::SHUTDOWN)
-                if (!DatabaseCatalog::instance().getDependencies(table_id).empty())
+                return;
-                    continue;
+
-                drop_table = true;
+            //if (storage->hasUsers())
-            }
+            //    return;
-            break;
+            //if (!DatabaseCatalog::instance().getDependencies(table_id).empty())
+            //    continue;
+            //if (storage->isTemporary())
+            //    drop_table = true;
+            continue;
         }
+        // timeout sleeping
+        std::cerr << "!!!: eventsThread timeout\n";
     }
 
-    if (drop_table)
+    /*if (drop_table)
     {
         if (DatabaseCatalog::instance().tryGetTable(table_id))
         {
@@ -434,46 +450,49 @@ void StorageLiveView::noUsersThread(std::shared_ptr<StorageLiveView> storage, co
                 tryLogCurrentException(__PRETTY_FUNCTION__);
             }
         }
+    }*/
+}
+
+void StorageLiveView::wakeupEventsThread(const LiveViewEvent & event)
+{
+    std::lock_guard events_thread_lock(events_thread_mutex);
+    if (events_thread.joinable())
+    {
+        std::lock_guard lock(events_thread_wakeup_mutex);
+        events_thread_wakeup = true;
+        events_thread_event |= event;
+        events_thread_event_timestamp_usec = static_cast<UInt64>(Poco::Timestamp().epochMicroseconds());
+
+        if (event == LiveViewEvent::NEW_USER)
+            events_thread_event &= ~static_cast<unsigned int>(LiveViewEvent::LAST_USER);
+        else if (event == LiveViewEvent::LAST_USER)
+            events_thread_event &= ~static_cast<unsigned int>(LiveViewEvent::NEW_USER);
+
+        events_thread_condition.notify_one();
     }
 }
 
-void StorageLiveView::startNoUsersThread(const UInt64 & timeout)
+void StorageLiveView::startEventsThread()
 {
-    bool expected = false;
+    if (is_temporary || is_auto_refreshed)
-    if (!start_no_users_thread_called.compare_exchange_strong(expected, true))
-        return;
-
-    if (is_temporary)
     {
-        std::lock_guard no_users_thread_lock(no_users_thread_mutex);
+        std::lock_guard events_thread_lock(events_thread_mutex);
 
-        if (shutdown_called)
+        if (events_thread.joinable())
             return;
 
-        if (no_users_thread.joinable())
         {
-            {
+            std::lock_guard lock(events_thread_wakeup_mutex);
-                std::lock_guard lock(no_users_thread_wakeup_mutex);
+            events_thread_wakeup = false;
-                no_users_thread_wakeup = true;
-                no_users_thread_condition.notify_one();
-            }
-            no_users_thread.join();
         }
-        {
+        events_thread = std::thread(&StorageLiveView::eventsThread,
-            std::lock_guard lock(no_users_thread_wakeup_mutex);
+            std::static_pointer_cast<StorageLiveView>(shared_from_this()));
-            no_users_thread_wakeup = false;
-        }
-        if (!is_dropped)
-            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()
 {
-    startNoUsersThread(temporary_live_view_timeout);
+    startEventsThread();
 }
 
 void StorageLiveView::shutdown()
@@ -484,13 +503,14 @@ void StorageLiveView::shutdown()
         return;
 
     {
-        std::lock_guard no_users_thread_lock(no_users_thread_mutex);
+        std::lock_guard events_thread_lock(events_thread_mutex);
-        if (no_users_thread.joinable())
+        if (events_thread.joinable())
         {
             {
-                std::lock_guard lock(no_users_thread_wakeup_mutex);
+                std::lock_guard lock(events_thread_wakeup_mutex);
-                no_users_thread_wakeup = true;
+                events_thread_wakeup = true;
-                no_users_thread_condition.notify_one();
+                events_thread_event = LiveViewEvent::SHUTDOWN;
+                events_thread_condition.notify_one();
             }
         }
     }
@@ -501,9 +521,9 @@ StorageLiveView::~StorageLiveView()
     shutdown();
 
     {
-        std::lock_guard lock(no_users_thread_mutex);
+        std::lock_guard lock(events_thread_mutex);
-        if (no_users_thread.joinable())
+        if (events_thread.joinable())
-            no_users_thread.detach();
+            events_thread.detach();
     }
 }
 
@@ -572,18 +592,9 @@ BlockInputStreams StorageLiveView::watch(
         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().live_view_heartbeat_interval.totalSeconds());
-            temporary_live_view_timeout);
 
-        {
+        wakeupEventsThread(LiveViewEvent::NEW_USER);
-            std::lock_guard no_users_thread_lock(no_users_thread_mutex);
-            if (no_users_thread.joinable())
-            {
-                std::lock_guard lock(no_users_thread_wakeup_mutex);
-                no_users_thread_wakeup = true;
-                no_users_thread_condition.notify_one();
-            }
-        }
 
         {
             std::lock_guard lock(mutex);
@@ -603,18 +614,9 @@ BlockInputStreams StorageLiveView::watch(
         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().live_view_heartbeat_interval.totalSeconds());
-            temporary_live_view_timeout);
 
-        {
+        wakeupEventsThread(LiveViewEvent::NEW_USER);
-            std::lock_guard no_users_thread_lock(no_users_thread_mutex);
-            if (no_users_thread.joinable())
-            {
-                std::lock_guard lock(no_users_thread_wakeup_mutex);
-                no_users_thread_wakeup = true;
-                no_users_thread_condition.notify_one();
-            }
-        }
 
         {
             std::lock_guard lock(mutex);

src/Storages/LiveView/StorageLiveView.h

@@ -13,6 +13,7 @@ limitations under the License. */
 
 #include <ext/shared_ptr_helper.h>
 #include <Storages/IStorage.h>
+#include <Storages/LiveView/Events.h>
 
 #include <mutex>
 #include <condition_variable>
@@ -72,6 +73,7 @@ public:
     bool supportsFinal() const override { return true; }
 
     bool isTemporary() { return is_temporary; }
+    bool isAutoRefreshed() { return is_auto_refreshed; }
 
     /// Check if we have any readers
     /// must be called with mutex locked
@@ -86,11 +88,14 @@ public:
     {
         return active_ptr.use_count() > 1;
     }
-    /// No users thread mutex, predicate and wake up condition
+
-    void startNoUsersThread(const UInt64 & timeout);
+    /// events thread mutex, predicate and wake up condition
-    std::mutex no_users_thread_wakeup_mutex;
+    void wakeupEventsThread(const LiveViewEvent & event);
-    bool no_users_thread_wakeup = false;
+    std::mutex events_thread_wakeup_mutex;
-    std::condition_variable no_users_thread_condition;
+    bool events_thread_wakeup = false;
+    unsigned int events_thread_event = 0;
+    UInt64 events_thread_event_timestamp_usec = 0;
+    std::condition_variable events_thread_condition;
     /// Get blocks hash
     /// must be called with mutex locked
     String getBlocksHashKey()
@@ -174,6 +179,7 @@ private:
     std::unique_ptr<Context> live_view_context;
 
     bool is_temporary = false;
+    bool is_auto_refreshed = false;
     /// Mutex to protect access to sample block and inner_blocks_query
     mutable std::mutex sample_block_lock;
     mutable Block sample_block;
@@ -192,14 +198,15 @@ private:
     std::shared_ptr<BlocksMetadataPtr> blocks_metadata_ptr;
     MergeableBlocksPtr mergeable_blocks;
 
-    /// Background thread for temporary tables
+    /// Background events thread for temporary and auto refresh tables
-    /// which drops this table if there are no users
+    void startEventsThread();
-    static void noUsersThread(std::shared_ptr<StorageLiveView> storage, const UInt64 & timeout);
+    static void eventsThread(std::shared_ptr<StorageLiveView> storage);
-    std::mutex no_users_thread_mutex;
+    std::mutex events_thread_mutex;
-    std::thread no_users_thread;
+    std::thread events_thread;
     std::atomic<bool> shutdown_called = false;
-    std::atomic<bool> start_no_users_thread_called = false;
+    std::atomic<bool> start_events_thread_called = false;
     UInt64 temporary_live_view_timeout;
+    UInt64 auto_refresh_live_view_interval;
 
     StorageLiveView(
         const StorageID & table_id_,