Operational best practices
Handling instance restarts and failovers
After a restart or failover, the on-disk cache starts empty, so the first queries run more slowly while they read from Amazon S3, and performance improves once the data is cached again. For latency-sensitive workloads, run a script of representative queries after a restart to populate the cache before production traffic resumes.
Setting up alarms
Create Amazon CloudWatch alarms that signal resource pressure, so you are notified before queries fail. For proactive monitoring, watch the following metrics.
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AuroraAnalyticsMemoryUsage: Memory consumed by foreign table queries. A rising value signals memory pressure and the risk of out-of-memory errors. -
AuroraAnalyticsCacheHitRatio: The share of reads served from the on-disk cache. A falling value means more queries are re-reading from Amazon S3, often because the working set exceeds the cache. -
AuroraAnalyticsDiskSpillSize: How much data queries are spilling to local storage. A rising value means queries are exceeding theirquery_memand can benefit from more memory or tuning. -
FreeLocalStorage(orFreeEphemeralStorageon NVMe instance classes): Local storage available for the cache and spill files. A falling value means the volume is filling up.
For the metric definitions, see Monitoring and troubleshooting.
For how to create alarms, see Using Amazon CloudWatch alarms in the Amazon CloudWatch User Guide.
