Troubleshooting latency issues - AWS Database Migration Service

Troubleshooting latency issues

This section contains troubleshooting steps for replication latency.

To troubleshoot latency, do the following:

  • First, determine the type and amount of latency for the task. Check the task's Table Statistics section from the DMS console or CLI. If the counters are changing, then data transmission is in progress. Check the CDCLatencySource andCDCLatencyTarget metrics together to determine if there's a bottleneck during CDC.

  • If high CDCLatencySource or CDCLatencyTarget metrics indicate a bottleneck in your replication, check the following:

    • If CDCLatencySource is high and CDCLatencyTarget is equal to CDCLatencySource, this indicates that there is a bottleneck in your source endpoint, and AWS DMS is writing data to the target smoothly. See Troubleshooting source latency issues following.

    • If CDCLatencySource is low and CDCLatencyTarget is high, this indicates that there is a bottleneck in your target endpoint, and AWS DMS is reading data from the source smoothly. See Troubleshooting target latency issues following.

    • If CDCLatencySource is high and CDCLatencyTarget is significantly higher than CDCLatencySource, this indicates bottlenecks on both source reads and target writes. Investigate source latency first, and then investigate target latency.

For information about monitoring DMS task metrics, see Monitoring AWS DMS tasks.