#include <db.h>

int
DB_TXN->set_priority(DB_TXN *tid, u_int32_t priority);  

The DB_TXN->set_priority() method sets the priority for the transaction. The deadlock detector will reject lock requests from lower priority transactions before those from higher priority transactions.

By default, all transactions are created with a priority of 100.

The DB_TXN->set_priority() method may be called at any time during the life of the transaction.

The DB_TXN->set_priority() method returns a non-zero error value on failure and 0 on success.