MySQL触发器。 如何在有限的时间内存储表中的每一行数据？

Question

There is a table in my database every row of which should be stored for a limited time (1 minute). I'm trying to do the ON INSERT trigger like this:

CREATE TRIGGER `temp_data_trig` AFTER INSERT ON `tokens`
FOR EACH ROW 
BEGIN
    DO SLEEP(60);
    DELETE FROM `tokens` WHERE id = NEW.id;
END

But when i'm trying to insert a new row i'm getting this:

Can't update table 'tokens' in stored function/trigger because it is 
already used by statement which invoked this stored function/trigger.

What is wrong with my trigger and what is the right way to store each row of data for a limited time?

Answer 1

In general, you don't want to do sleep in a trigger. That just locks the table.

I would suggest that you take one of the following approaches.

The first is to include the date/time stamp when something is inserted. Then have a job that goes through an deletes records more than a minute old. Do note that this puts a fair amount of load on the database. Alternatively, you could just keep all the records, inserting them at will, and have a view that selects the ones created in the last minute:

create view v_table
    select *
    from table
    where createdat >= now() - interval 1 minute;

The final solution is to partition the data by minute intervals. Then you can drop partitions with minimal impact on the performance of the database ("minimal" relative to other options that might lock the table for longer periods of time).