From 5baba1fb116b5dbe94869f3894617045b653473a Mon Sep 17 00:00:00 2001 From: =?utf-8?q?Tarmo=20T=C3=A4nav?= Date: Tue, 26 Aug 2008 04:55:57 +0300 Subject: [PATCH] Cache migrated versions list in Migrator and use it to fetch the latest migrated version name [#845 state:resolved] Also optimized Migrator#current_version class method to fetch only the latest version number and not all of them. With this change no matter how many migrations there are the schema_migrations table is only SELECTed from once. --- activerecord/lib/active_record/migration.rb | 14 ++++++++------ 1 files changed, 8 insertions(+), 6 deletions(-) diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb index c7bc762..7a1fd7c 100644 --- a/activerecord/lib/active_record/migration.rb +++ b/activerecord/lib/active_record/migration.rb @@ -407,10 +407,9 @@ module ActiveRecord end def current_version - version = Base.connection.select_values( - "SELECT version FROM #{schema_migrations_table_name}" - ).map(&:to_i).max rescue nil - version || 0 + Base.connection.select_value( + "SELECT MAX(CAST(version AS integer)) FROM #{schema_migrations_table_name}" + ).to_i rescue 0 end def proper_table_name(name) @@ -426,7 +425,7 @@ module ActiveRecord end def current_version - self.class.current_version + migrated.last || 0 end def current_migration @@ -518,16 +517,19 @@ module ActiveRecord def migrated sm_table = self.class.schema_migrations_table_name - Base.connection.select_values("SELECT version FROM #{sm_table}").map(&:to_i).sort + @migrated_versions ||= Base.connection.select_values("SELECT version FROM #{sm_table}").map(&:to_i).sort end private def record_version_state_after_migrating(version) sm_table = self.class.schema_migrations_table_name + @migrated_versions ||= [] if down? + @migrated_versions.delete(version.to_i) Base.connection.update("DELETE FROM #{sm_table} WHERE version = '#{version}'") else + @migrated_versions.push(version.to_i).sort! Base.connection.insert("INSERT INTO #{sm_table} (version) VALUES ('#{version}')") end end -- 1.6.0