Re: Understanding Deadlocks in MySQL
Posted by: Peter Brawley
Date: November 22, 2019 02:26PM

Are these transactions coded to retry in the event of deadlock?

What MySQL version is this?

Is the InnoDB Lock Monitor on?

What does information_schema.innodb_locks (performance_schema since 5.7) show?

In the 2nd query, is the app code that generates multiple ...set x=ifnull(some_input_value,x)... sql clauses inciting reads and therefore S locks? Did you try changing the code to something like (pseudocode) ...

if new value is not null then add a set clause for this value

Edited 1 time(s). Last edit at 11/22/2019 02:31PM by Peter Brawley.

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Re: Understanding Deadlocks in MySQL
November 22, 2019 02:26PM

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