Deadlock found when trying to get a lock

Deadlock found when trying to get a lock

Hi,

This situation occurs when two transaction hold on each other to again lock. So, concurrent transactions never try to update a row which creates deadlock.

T1: lock x, then y

T 2: lock y, then x

To avoid the deadlock, change the queries such that transactions would lock at same order.

T 1: locks key x, locks key y;

T 2: locks key x, locks key y;

There can also be problem of missing indexes. Always make sure to have indexes on foreign or primary keys. If not done this way, this could result in table lock instead of row lock.