1
我在包含大量行的表运行在我的Rails应用程序下面的迁移时:获取死锁改变表
rake db:migrate
*** [] rake aborted!
*** [] An error has occurred, this and all later migrations canceled:
*** []
*** [] PG::Error: ERROR: deadlock detected
*** [] DETAIL: Process 33319 waits for AccessExclusiveLock on relation 18486 of database 16948; blocked by process 29772.
*** [] Process 29772 waits for ShareLock on transaction 8652; blocked by process 33319.
*** [] HINT: See server log for query details.
*** [] : ALTER TABLE "topics" DROP "most_recent_post_id"
*** []
*** [] Tasks: TOP => db:migrate
*** [] (See full trace by running task with --trace)
** [] == RemoveMostRecentPostsColumnsOnTopics: migrating
** [] Updated 56875150 rows out of 568715 tries
** [] -- remove_column(:topics, :most_recent_post_id)
运行的代码是这样的:
def self.up
rows_updated = 0
rows_tried = 0
Topic.find(:all).each do |topic|
rows_tried += 1
rows_updated += 1 if topic.update_attribute :updated_at, topic.most_recent_post_created_at
end
puts "Updated #{rows_updated} rows out of #{rows_tried} tries"
remove_column :topics, :most_recent_post_id
remove_column :topics, :most_recent_post_created_at
end
我然后试图做一个明确的锁,但是当搜索有关问题的信息时,我意识到ALTER TABLE已经用ACCESS EXCLUSIVE锁来锁定表,根据这个:http://www.postgresql.org/docs/9.1/static/explicit-locking.html
我能做些什么来完成我的更改?
你怎样开始你的交易?你多久做一次? – vyegorov 2012-04-26 10:02:41