1 files changed, 26 insertions, 15 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index 3fbbb46f73..b2345fd571 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -13,23 +13,25 @@ module MysqlCompat #:nodoc:
     # C driver >= 2.7 returns null values in each_hash
     if Mysql.const_defined?(:VERSION) && (Mysql::VERSION.is_a?(String) || Mysql::VERSION >= 20700)
       target.class_eval <<-'end_eval'
-      def all_hashes
-        rows = []
-        each_hash { |row| rows << row }
-        rows
-      end
+      def all_hashes                     # def all_hashes
+        rows = []                        #   rows = []
+        each_hash { |row| rows << row }  #   each_hash { |row| rows << row }
+        rows                             #   rows
+      end                                # end
       end_eval
 
     # adapters before 2.7 don't have a version constant
     # and don't return null values in each_hash
     else
       target.class_eval <<-'end_eval'
-      def all_hashes
-        rows = []
-        all_fields = fetch_fields.inject({}) { |fields, f| fields[f.name] = nil; fields }
-        each_hash { |row| rows << all_fields.dup.update(row) }
-        rows
-      end
+      def all_hashes                                            # def all_hashes
+        rows = []                                               #   rows = []
+        all_fields = fetch_fields.inject({}) { |fields, f|      #   all_fields = fetch_fields.inject({}) { |fields, f|
+          fields[f.name] = nil; fields                          #     fields[f.name] = nil; fields
+        }                                                       #   }
+        each_hash { |row| rows << all_fields.dup.update(row) }  #   each_hash { |row| rows << all_fields.dup.update(row) }
+        rows                                                    #   rows
+      end                                                       # end
       end_eval
     end
 
@@ -312,6 +314,7 @@ module ActiveRecord
         rows
       end
 
+      # Executes a SQL query and returns a MySQL::Result object. Note that you have to free the Result object after you're done using it.
       def execute(sql, name = nil) #:nodoc:
         log(sql, name) { @connection.query(sql) }
       rescue ActiveRecord::StatementInvalid => exception
@@ -429,7 +432,9 @@ module ActiveRecord
 
       def tables(name = nil) #:nodoc:
         tables = []
-        execute("SHOW TABLES", name).each { |field| tables << field[0] }
+        result = execute("SHOW TABLES", name)
+        result.each { |field| tables << field[0] }
+        result.free
         tables
       end
 
@@ -440,7 +445,8 @@ module ActiveRecord
       def indexes(table_name, name = nil)#:nodoc:
         indexes = []
         current_index = nil
-        execute("SHOW KEYS FROM #{quote_table_name(table_name)}", name).each do |row|
+        result = execute("SHOW KEYS FROM #{quote_table_name(table_name)}", name)
+        result.each do |row|
           if current_index != row[2]
             next if row[2] == "PRIMARY" # skip the primary key
             current_index = row[2]
@@ -449,13 +455,16 @@ module ActiveRecord
 
           indexes.last.columns << row[4]
         end
+        result.free
         indexes
       end
 
       def columns(table_name, name = nil)#:nodoc:
         sql = "SHOW FIELDS FROM #{quote_table_name(table_name)}"
         columns = []
-        execute(sql, name).each { |field| columns << MysqlColumn.new(field[0], field[4], field[1], field[2] == "YES") }
+        result = execute(sql, name)
+        result.each { |field| columns << MysqlColumn.new(field[0], field[4], field[1], field[2] == "YES") }
+        result.free
         columns
       end
 
@@ -536,9 +545,11 @@ module ActiveRecord
       # Returns a table's primary key and belonging sequence.
       def pk_and_sequence_for(table) #:nodoc:
         keys = []
-        execute("describe #{quote_table_name(table)}").each_hash do |h|
+        result = execute("describe #{quote_table_name(table)}")
+        result.each_hash do |h|
           keys << h["Field"]if h["Key"] == "PRI"
         end
+        result.free
         keys.length == 1 ? [keys.first, nil] : nil
       end