database_atomic_wait_for_drop_and_detach_synchronously/NO DELAY/SYNC for DROP DATABASE

src/Interpreters/InterpreterDropQuery.cpp

@@ -52,7 +52,7 @@ BlockIO InterpreterDropQuery::execute()
             return executeToDictionary(drop.database, drop.table, drop.kind, drop.if_exists, drop.temporary, drop.no_ddl_lock);
     }
     else if (!drop.database.empty())
-        return executeToDatabase(drop.database, drop.kind, drop.if_exists);
+        return executeToDatabase(drop.database, drop.kind, drop.if_exists, drop.no_delay);
     else
         throw Exception("Nothing to drop, both names are empty", ErrorCodes::LOGICAL_ERROR);
 }
@@ -223,7 +223,7 @@ BlockIO InterpreterDropQuery::executeToTemporaryTable(const String & table_name,
 }
 
 
-BlockIO InterpreterDropQuery::executeToDatabase(const String & database_name, ASTDropQuery::Kind kind, bool if_exists)
+BlockIO InterpreterDropQuery::executeToDatabase(const String & database_name, ASTDropQuery::Kind kind, bool if_exists, bool no_delay)
 {
     auto ddl_guard = DatabaseCatalog::instance().getDDLGuard(database_name, "");
 
@@ -252,8 +252,12 @@ BlockIO InterpreterDropQuery::executeToDatabase(const String & database_name, AS
                 ASTDropQuery query;
                 query.kind = kind;
                 query.database = database_name;
+                query.no_delay = no_delay;
+
                 for (auto iterator = database->getTablesIterator(context); iterator->isValid(); iterator->next())
                 {
+                    /// Reset reference counter of the StoragePtr to allow synchronous drop.
+                    iterator->reset();
                     query.table = iterator->name();
                     executeToTable({query.database, query.table}, query);
                 }

src/Interpreters/InterpreterDropQuery.h

@@ -29,7 +29,7 @@ private:
     ASTPtr query_ptr;
     Context & context;
 
-    BlockIO executeToDatabase(const String & database_name, ASTDropQuery::Kind kind, bool if_exists);
+    BlockIO executeToDatabase(const String & database_name, ASTDropQuery::Kind kind, bool if_exists, bool no_delay);
 
     BlockIO executeToTable(const StorageID & table_id, const ASTDropQuery & query);
 

src/Parsers/ParserDropQuery.cpp

@@ -46,6 +46,9 @@ bool parseDropQuery(IParser::Pos & pos, ASTPtr & node, Expected & expected, bool
             if (!ASTQueryWithOnCluster::parse(pos, cluster_str, expected))
                 return false;
         }
+
+        if (s_no_delay.ignore(pos, expected) || s_sync.ignore(pos, expected))
+            no_delay = true;
     }
     else
     {

tests/queries/0_stateless/01530_drop_database_atomic_sync.sql

@@ -0,0 +1,34 @@
+drop database if exists db_01530_atomic sync;
+
+create database db_01530_atomic Engine=Atomic;
+create table db_01530_atomic.data (key Int) Engine=ReplicatedMergeTree('/clickhouse/tables/db_01530_atomic/data', 'test') order by key;
+drop database db_01530_atomic sync;
+
+create database db_01530_atomic Engine=Atomic;
+create table db_01530_atomic.data (key Int) Engine=ReplicatedMergeTree('/clickhouse/tables/db_01530_atomic/data', 'test') order by key;
+drop database db_01530_atomic sync;
+
+
+set database_atomic_wait_for_drop_and_detach_synchronously=1;
+
+create database db_01530_atomic Engine=Atomic;
+create table db_01530_atomic.data (key Int) Engine=ReplicatedMergeTree('/clickhouse/tables/db_01530_atomic/data', 'test') order by key;
+drop database db_01530_atomic;
+
+create database db_01530_atomic Engine=Atomic;
+create table db_01530_atomic.data (key Int) Engine=ReplicatedMergeTree('/clickhouse/tables/db_01530_atomic/data', 'test') order by key;
+drop database db_01530_atomic;
+
+
+set database_atomic_wait_for_drop_and_detach_synchronously=0;
+
+create database db_01530_atomic Engine=Atomic;
+create table db_01530_atomic.data (key Int) Engine=ReplicatedMergeTree('/clickhouse/tables/db_01530_atomic/data', 'test') order by key;
+drop database db_01530_atomic;
+
+create database db_01530_atomic Engine=Atomic;
+create table db_01530_atomic.data (key Int) Engine=ReplicatedMergeTree('/clickhouse/tables/db_01530_atomic/data', 'test') order by key; -- { serverError 253; }
+-- TODO: SYSTEM FORCE DROP and uncomment the line below to cleanup the data after test
+-- (otherwise the test is not retriable...)
+--
+-- drop database db_01530_atomic sync;