Optimization

You can take certain actions if you feel that the inventory lock contention levels are high to increase optimization.

If the inventory lock contention level is high, relative to your processing concurrency levels, or if you feel that your processing throughput or end-user response times are impacted, we suggest the following course of action.

Look at the lock-holding times. Run each inventory processing transaction with SQLDEBUG traces or possibly VERBOSE traces. VERBOSE traces provides more data but can be more intrusive than SQLDEBUG:

• See how long, on average, the transactions take.
• See when the first inventory locks are obtained (and as a result, how long they are held) within that transaction boundary. The goal is to keep lock-holding times short.
• See if there are places in the transaction that take a long time to process and the processing occurs when inventory item locks are held. For example:
  • The transaction may have a user-exit that calls out to external systems. If that external system slows down or is unable to scale, the user-exit time increases. This elongates the lock-holding times.
  • There may be SQL statements that run for a long time and can be optimized with better database statistics or an additional index.
  • Look at the GC logs - Make sure the transaction is not slowed down by long costly garbage collection pauses.

Reducing lock-holding times can have compounding effects - as lock-holding times decreases, transactions finish faster and, as a result, lower concurrency levels.