CompTIA DataSys+ (DS0-001)Database Management and MaintenanceMedium
A database administrator is setting up monitoring for a new database. They need to track the amount of time queries spend waiting for locks, which is causing intermittent performance issues. Which metric should the administrator prioritize monitoring to identify and troubleshoot these lock-related delays?
- ACPU utilization percentage.
- BLock wait time.
- CDisk I/O latency.
- DBuffer cache hit ratio.
Show answer & explanationAnswer & explanation
Correct answer: B. Lock wait time.
Lock wait time directly measures the duration that queries or transactions spend waiting to acquire a lock on a resource. High lock wait times are a direct indicator of contention and are crucial for troubleshooting intermittent performance issues caused by locking.
Why the other options are wrong
- A. CPU utilization is a general performance metric; while high CPU can impact overall performance, it doesn't directly indicate locking issues.
- C. Disk I/O latency measures how long it takes for disk operations. High latency can cause slow queries, but it's not the primary metric for identifying lock contention.
- D. Buffer cache hit ratio measures how often data is found in memory rather than needing to be read from disk. A low ratio indicates I/O bottlenecks, not necessarily locking.
Lock Wait Time
The cumulative or average time that database processes spend waiting to acquire locks on database resources.
- High lock wait times indicate contention for shared resources.
- A key metric for diagnosing concurrency and blocking issues.
- Monitoring this helps identify queries or transactions causing excessive locking.
Memory trick: Each metric tells a specific story.