1 files changed, 14 insertions, 19 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 282b2b1838..ef1eef6b69 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -45,7 +45,6 @@ module ActiveRecord
 
       class StatementPool < ConnectionAdapters::StatementPool # :nodoc:
         private
-
           def dealloc(stmt)
             stmt.close
           end
@@ -176,15 +175,6 @@ module ActiveRecord
       # DATABASE STATEMENTS ======================================
       #++
 
-      def explain(arel, binds = [])
-        sql     = "EXPLAIN #{to_sql(arel, binds)}"
-        start   = Concurrent.monotonic_time
-        result  = exec_query(sql, "EXPLAIN", binds)
-        elapsed = Concurrent.monotonic_time - start
-
-        MySQL::ExplainPrettyPrinter.new.pp(result, elapsed)
-      end
-
       # Executes the SQL statement in the context of this connection.
       def execute(sql, name = nil)
         materialize_transactions
@@ -204,7 +194,7 @@ module ActiveRecord
       end
 
       def begin_db_transaction
-        execute "BEGIN"
+        execute("BEGIN", "TRANSACTION")
       end
 
       def begin_isolated_db_transaction(isolation)
@@ -213,11 +203,11 @@ module ActiveRecord
       end
 
       def commit_db_transaction #:nodoc:
-        execute "COMMIT"
+        execute("COMMIT", "TRANSACTION")
       end
 
       def exec_rollback_db_transaction #:nodoc:
-        execute "ROLLBACK"
+        execute("ROLLBACK", "TRANSACTION")
       end
 
       def empty_insert_statement_value(primary_key = nil)
@@ -298,6 +288,8 @@ module ActiveRecord
       # Example:
       #   rename_table('octopuses', 'octopi')
       def rename_table(table_name, new_name)
+        schema_cache.clear_data_source_cache!(table_name.to_s)
+        schema_cache.clear_data_source_cache!(new_name.to_s)
         execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
         rename_table_indexes(table_name, new_name)
       end
@@ -318,6 +310,7 @@ module ActiveRecord
       # it can be helpful to provide these in a migration's +change+ method so it can be reverted.
       # In that case, +options+ and the block will be used by create_table.
       def drop_table(table_name, options = {})
+        schema_cache.clear_data_source_cache!(table_name.to_s)
         execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
       end
 
@@ -483,12 +476,12 @@ module ActiveRecord
       # distinct queries, and requires that the ORDER BY include the distinct column.
       # See https://dev.mysql.com/doc/refman/5.7/en/group-by-handling.html
       def columns_for_distinct(columns, orders) # :nodoc:
-        order_columns = orders.reject(&:blank?).map { |s|
+        order_columns = orders.compact_blank.map { |s|
           # Convert Arel node to string
           s = s.to_sql unless s.is_a?(String)
           # Remove any ASC/DESC modifiers
           s.gsub(/\s+(?:ASC|DESC)\b/i, "")
-        }.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }
+        }.compact_blank.map.with_index { |column, i| "#{column} AS alias_#{i}" }
 
         (order_columns << super).join(", ")
       end
@@ -522,7 +515,6 @@ module ActiveRecord
       end
 
       private
-
         def initialize_type_map(m = type_map)
           super
 
@@ -627,7 +619,11 @@ module ActiveRecord
           when ER_QUERY_INTERRUPTED
             QueryCanceled.new(message, sql: sql, binds: binds)
           else
-            super
+            if exception.is_a?(Mysql2::Error::TimeoutError)
+              ActiveRecord::AdapterTimeout.new(message, sql: sql, binds: binds)
+            else
+              super
+            end
           end
         end
 
@@ -745,7 +741,7 @@ module ActiveRecord
           end.compact.join(", ")
 
           # ...and send them all in one query
-          execute "SET #{encoding} #{sql_mode_assignment} #{variable_assignments}"
+          execute("SET #{encoding} #{sql_mode_assignment} #{variable_assignments}", "SCHEMA")
         end
 
         def column_definitions(table_name) # :nodoc:
@@ -804,7 +800,6 @@ module ActiveRecord
           end
 
           private
-
             def cast_value(value)
               case value
               when true then "1"