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Made migrations transactional for PostgreSQL [#834 state:resolved]

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1 parent 9dac554 commit 707ee0e2695e85186d59aa407f09691ebfcc3125 @tarmo tarmo committed with jeremy Aug 22, 2008
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2 activerecord/CHANGELOG
@@ -1,5 +1,7 @@
*Edge*
+* Transactional migrations for databases which support them. #834 [divoxx, Adam Wiggins, Tarmo Tänav]
+
* Set config.active_record.timestamped_migrations = false to have migrations with numeric prefix instead of UTC timestamp. #446. [Andrew Stone, Nik Wakelin]
* change_column_default preserves the not-null constraint. #617 [Tarmo Tänav]
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7 activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -51,6 +51,13 @@ def supports_count_distinct?
true
end
+ # Does this adapter support DDL rollbacks in transactions? That is, would
+ # CREATE TABLE or ALTER TABLE get rolled back by a transaction? PostgreSQL,
+ # SQL Server, and others support this. MySQL and others do not.
+ def supports_ddl_transactions?
+ false
+ end
+
# Should primary key values be selected from their corresponding
# sequence before the insert statement? If true, next_sequence_value
# is called before each insert to set the record's primary key.
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4 activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -335,6 +335,10 @@ def supports_insert_with_returning?
postgresql_version >= 80200
end
+ def supports_ddl_transactions?
+ true
+ end
+
# Returns the configured supported identifier length supported by PostgreSQL,
# or report the default of 63 on PostgreSQL 7.x.
def table_alias_length
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25 activerecord/lib/active_record/migration.rb
@@ -461,14 +461,22 @@ def migrate
Base.logger.info "Migrating to #{migration.name} (#{migration.version})"
# On our way up, we skip migrating the ones we've already migrated
- # On our way down, we skip reverting the ones we've never migrated
next if up? && migrated.include?(migration.version.to_i)
+ # On our way down, we skip reverting the ones we've never migrated
if down? && !migrated.include?(migration.version.to_i)
migration.announce 'never migrated, skipping'; migration.write
- else
- migration.migrate(@direction)
- record_version_state_after_migrating(migration.version)
+ next
+ end
+
+ begin
+ ddl_transaction do
+ migration.migrate(@direction)
+ record_version_state_after_migrating(migration.version)
+ end
+ rescue => e
+ canceled_msg = Base.connection.supports_ddl_transactions? ? "this and " : ""
+ raise StandardError, "An error has occurred, #{canceled_msg}all later migrations canceled:\n\n#{e}", e.backtrace
end
end
end
@@ -531,5 +539,14 @@ def up?
def down?
@direction == :down
end
+
+ # Wrap the migration in a transaction only if supported by the adapter.
+ def ddl_transaction(&block)
+ if Base.connection.supports_ddl_transactions?
+ Base.transaction { block.call }
+ else
+ block.call
+ end
+ end
end
end
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15 activerecord/test/cases/migration_test.rb
@@ -937,6 +937,21 @@ def test_migrator_double_down
assert_equal(0, ActiveRecord::Migrator.current_version)
end
+ if current_adapter?(:PostgreSQLAdapter)
+ def test_migrator_one_up_with_exception_and_rollback
+ assert !Person.column_methods_hash.include?(:last_name)
+
+ e = assert_raises(StandardError) do
+ ActiveRecord::Migrator.up(MIGRATIONS_ROOT + "/broken", 100)
+ end
+
+ assert_equal "An error has occurred, this and all later migrations canceled:\n\nSomething broke", e.message
+
+ Person.reset_column_information
+ assert !Person.column_methods_hash.include?(:last_name)
+ end
+ end
+
def test_finds_migrations
migrations = ActiveRecord::Migrator.new(:up, MIGRATIONS_ROOT + "/valid").migrations
[['1', 'people_have_last_names'],
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10 activerecord/test/migrations/broken/100_migration_that_raises_exception.rb
@@ -0,0 +1,10 @@
+class MigrationThatRaisesException < ActiveRecord::Migration
+ def self.up
+ add_column "people", "last_name", :string
+ raise 'Something broke'
+ end
+
+ def self.down
+ remove_column "people", "last_name"
+ end
+end

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