SHOW CREATE for DatabaseMemory

dbms/src/Databases/DatabaseMemory.cpp

@@ -9,6 +9,11 @@
 namespace DB
 {
 
+namespace ErrorCodes
+{
+    extern const int UNKNOWN_TABLE;
+}
+
 DatabaseMemory::DatabaseMemory(const String & name_)
     : DatabaseWithOwnTablesBase(name_, "DatabaseMemory(" + name_ + ")")
     , data_path("data/" + escapeForFileName(database_name) + "/")
@@ -18,16 +23,19 @@ void DatabaseMemory::createTable(
     const Context & /*context*/,
     const String & table_name,
     const StoragePtr & table,
-    const ASTPtr & /*query*/)
+    const ASTPtr & query)
 {
-    attachTable(table_name, table);
+    std::lock_guard lock{mutex};
+    attachTableUnlocked(table_name, table);
+    create_queries.emplace(table_name, query);
 }
 
 void DatabaseMemory::dropTable(
     const Context & /*context*/,
     const String & table_name)
 {
-    auto table = detachTable(table_name);
+    std::lock_guard lock{mutex};
+    auto table = detachTableUnlocked(table_name);
     try
     {
         table->drop();
@@ -37,9 +45,11 @@ void DatabaseMemory::dropTable(
     }
     catch (...)
     {
-        attachTable(table_name, table);
+        attachTableUnlocked(table_name, table);
+        throw;
     }
     table->is_dropped = true;
+    create_queries.erase(table_name);
 }
 
 ASTPtr DatabaseMemory::getCreateDatabaseQuery(const Context & /*context*/) const
@@ -51,4 +61,13 @@ ASTPtr DatabaseMemory::getCreateDatabaseQuery(const Context & /*context*/) const
     return create_query;
 }
 
+ASTPtr DatabaseMemory::getCreateTableQueryImpl(const Context &, const String & table_name, bool throw_on_error) const
+{
+    std::lock_guard lock{mutex};
+    auto it = create_queries.find(table_name);
+    if (it == create_queries.end() && throw_on_error)
+        throw Exception("No table " + table_name + " in database " + database_name, ErrorCodes::UNKNOWN_TABLE);
+    return it->second;
+}
+
 }

dbms/src/Databases/DatabaseMemory.h

@@ -33,6 +33,7 @@ public:
         const Context & context,
         const String & table_name) override;
 
+    ASTPtr getCreateTableQueryImpl(const Context & /*context*/, const String & name, bool throw_on_error) const override;
     ASTPtr getCreateDatabaseQuery(const Context & /*context*/) const override;
 
     /// DatabaseMemory allows to create tables, which store data on disk.
@@ -44,6 +45,8 @@ public:
 
 private:
     String data_path;
+    using NameToASTCreate = std::unordered_map<String, ASTPtr>;
+    NameToASTCreate create_queries;
 };
 
 }

dbms/src/Databases/DatabasesCommon.cpp

@@ -67,9 +67,13 @@ bool DatabaseWithOwnTablesBase::empty(const Context & /*context*/) const
 
 StoragePtr DatabaseWithOwnTablesBase::detachTable(const String & table_name)
 {
-    StoragePtr res;
-    {
     std::lock_guard lock(mutex);
+    return detachTableUnlocked(table_name);
+}
+
+StoragePtr DatabaseWithOwnTablesBase::detachTableUnlocked(const String & table_name)
+{
+    StoragePtr res;
     if (dictionaries.count(table_name))
         throw Exception("Cannot detach dictionary " + database_name + "." + table_name + " as table, use DETACH DICTIONARY query.", ErrorCodes::UNKNOWN_TABLE);
 
@@ -78,14 +82,18 @@ StoragePtr DatabaseWithOwnTablesBase::detachTable(const String & table_name)
         throw Exception("Table " + backQuote(database_name) + "." + backQuote(table_name) + " doesn't exist.", ErrorCodes::UNKNOWN_TABLE);
     res = it->second;
     tables.erase(it);
-    }
 
     return res;
 }
 
-void DatabaseWithOwnTablesBase::attachTable(const String & table_name, const StoragePtr & table, const String &)
+void DatabaseWithOwnTablesBase::attachTable(const String & table_name, const StoragePtr & table, const String & relative_table_path)
 {
     std::lock_guard lock(mutex);
+    attachTableUnlocked(table_name, table, relative_table_path);
+}
+
+void DatabaseWithOwnTablesBase::attachTableUnlocked(const String & table_name, const StoragePtr & table, const String &)
+{
     if (!tables.emplace(table_name, table).second)
         throw Exception("Table " + database_name + "." + table_name + " already exists.", ErrorCodes::TABLE_ALREADY_EXISTS);
 }

dbms/src/Databases/DatabasesCommon.h

@@ -47,6 +47,9 @@ protected:
     Poco::Logger * log;
 
     DatabaseWithOwnTablesBase(const String & name_, const String & logger);
+
+    void attachTableUnlocked(const String & table_name, const StoragePtr & table, const String & relative_table_path = {});
+    StoragePtr detachTableUnlocked(const String & table_name);
 };
 
 }

dbms/tests/queries/0_stateless/01069_database_memory.reference

@@ -5,3 +5,4 @@ CREATE DATABASE memory_01069 ENGINE = Memory()
 4
 3
 4
+CREATE TABLE memory_01069.file (`n` UInt8) ENGINE = File(CSV)

dbms/tests/queries/0_stateless/01069_database_memory.sql

@@ -15,4 +15,7 @@ DROP TABLE memory_01069.mt;
 SELECT * FROM memory_01069.mt ORDER BY n; -- { serverError 60 }
 SELECT * FROM memory_01069.file ORDER BY n;
 
+SHOW CREATE TABLE memory_01069.mt; -- { serverError 60 }
+SHOW CREATE TABLE memory_01069.file;
+
 DROP DATABASE memory_01069;