Answer 1

Depends on the RDBMS, and how the locking contention works.

The main concern would be locking a table or rows that the erp application is trying to access at the same time. Some RDBMS allow you to access a table or rows via a "dirty read" or a very low-level lock, which bypasses any concurrent read or write locks. This is fine so long as you don't care if the data u retreive changes as/when you access it, or you don't care about the latest state of the data.

Using a "dirty read" lock, prevents the database application from having to retry operations or wait to get a lock before it can do something also