System log table health

Answers "are the system logs usable and are they eating the disk?" from system.tables, system.parts, system.disks, system.query_thread_log and system.crash_log. Other skills depend on these tables, so run this first when a pack returns no data. Run altinity-expert-clickhouse-connection first if the connection mode, cluster and time window are not yet established.

Query packs

• checks.sql — 6 checks emitting Altinity ids A0.2.01 through A0.2.08: query_log and part_log freshness, query_log data older than 30 days, system log tables without TTL, system logs using more than 20 percent of a disk, system.*_logN leftovers from version upgrades, query_thread_log still enabled, and recent crash_log records. Every statement returns rows only when a rule is broken, so an empty result is OK. Check A0.2.01 needs system.part_log, A0.2.07 needs system.query_thread_log and A0.2.08 needs system.crash_log; skip them when those tables are absent.
• 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.