I recently did a raffle
everyone can only draw once
I want to insert a record for each lucky draw request, and then read the first record for comparison to determine whether he is drawing the lottery for the first time, delete the useless record if not for the first time, and return an error
will there be a large number of innsert delete operations
will these two operations lock the table?
intercept with redis cache, and then use ON DUPLICATE KEY UPDATE to see the number of rows returned. The returned result
innodb engine's insert,update,delete operation adds exclusive locks (row-level locks) to the operation data. No other transaction can operate on this row of data at this time.
1. I feel so troublesome that
2.InnoDB is a row lock
in addition to @ start2004's answer, you can also put the request of each role into a separate queue, so that you can query first and then insert
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