Re: Simulating sequences

[Bonnie Kenison]

>>>last_insert_id() doesn't work with deletion. Any possibility a row was deleted by another process?

This is not a table we do deletions on (except for an overnight clean-up routine), so I can safely say that no threads are deleting.

>>>No error messages after that execute() call? No errors or warnings in the mysql or php logs?

I am using Java, but there are no exceptions or warnings. The only difference is that I sometimes get a "zero rows updated" situation.

>>>Did you try putting the code in a standard transaction block with rollback code?

I have the code in a single transaction - with just the two sql statements (the update and the select last_update_id). I could put in some error handling to simply rollback/retry the update statement when I get a zero rows updated situation, but I want to understand the situation first.

So, back to the original question: Is the update statement SUPPOSED to lock the row for its full execution (read/increment/update) or is that not thread safe?