#5752 "Container CPU and memory history lives in the one metric store; docker_metrics and docker_metrics_hourly are retired". Container cpu_pct and mem_pct already went to plugin_metrics for alerting; now mem_usage_bytes does too, and every snapshot in an ingest (backlog included) is recorded at its own time. The container history chart, Busiest Containers, a service's history and the MCP container tools read plugin_metrics under resource "<host>/<container>", rolled up and pruned by the shared metric retention. docker_012_drop_metrics drops both tables. Their history is not copied (lesson #5221 "A data migration's cost is set by the live table"); the store already holds 7 days of container CPU and memory %. Docker retention now prunes only lifecycle events, and Settings -> Thresholds has one "Metric retention" card for every source. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>