Real-time metrics and saturation

Answers "which resource is saturated right now, and was it saturated an hour ago?" from system.metrics, system.events, system.asynchronous_metrics, system.metric_log and system.asynchronous_metric_log. Run altinity-expert-clickhouse-connection first if the connection mode, cluster and time window are not yet established.

Query packs

• checks.sql — 12 checks (ids metrics-01 to metrics-12) in 14 statements: saturation summary for memory, running queries and connections; load average versus CPU cores; replication metrics; max parts per partition versus the insert thresholds; background pool utilization; failure and throttling counters since start; memory and load average over the last 6 hours; query rate over the last hour; block device queue depth; uptime and version; Prometheus endpoint configuration. Checks metrics-02 and metrics-10 exist twice with complementary @requires version<26.8 and @requires version>=26.8 headers: run only the one matching the server version. Checks metrics-07 and metrics-08 need system.asynchronous_metric_log, metrics-09 needs system.metric_log.
• reference.md — background (settings, sizing, anti-patterns); read only when you need to explain a recommendation.

How to run the query packs

1. Read each pack file from this skill's directory (the skill loader prints the directory path).
2. Run statements one at a time, never a whole file. Statements end with ; and start with a -- @check <id> <title> header; keep the id with its result.
3. Honor -- @requires: skip the statement when the named table is missing, when keeper is required and the server has no Keeper/ZooKeeper, or when the version condition is not met. List skipped ids with the reason.
4. Keep {cluster} as written when a cluster macro exists; otherwise apply the connection skill's rewrite rule. Any other {placeholder} is a template variable: substitute a real value first or skip the statement.
5. On an error, record the check id and the first line of the error, then continue. Only for UNKNOWN_IDENTIFIER, run DESCRIBE TABLE system.<table> and drop the missing column.
6. A severity column is the verdict for that row. Copy it; do not re-grade.