Reviewed against the ClickHouse Useful queries for troubleshooting page on 2026-07-16. External examples are adapted to bounded, typed, read-only items; they are not copied blindly.
| Diagnostic | Disposition | ch_diag item / reason |
|---|---|---|
| Changed settings | covered | overview.changed_settings |
| Table sizes | covered | db_top_tables and storage breakdown |
| Rows and daily growth | new_item P1 | deferred; requires safe date-range semantics |
| Compression and primary index | new_item P0 | dba_troubleshooting.column_compression, storage_breakdown |
| Queries per client | new_item P1 | deferred bounded historical item |
| Parts by partition | extend_existing P0 | storage_breakdown, partition_part_counts |
| Long-running current queries | covered | activity.proc_current |
| Query stack trace | optional_ad_hoc | deliberately excluded from automatic reports |
| Recent system errors | covered | errors.errors_last, errors.errors_top |
| Top CPU and memory queries | new_item P0 | dba_troubleshooting.top_cpu_memory; no raw query text |
| Projection size | new_item P1 | deferred capability-gated item |
| Disk/parts/rows/marks breakdown | new_item P0 | dba_troubleshooting.storage_breakdown |
| Recent level-0 parts | new_item P1 | deferred bounded item |
| Part creation rate | new_item P0 | optional snapshot_charts_clickhouse.part_creation_rate from system.part_log |
| Merges with ETA | extend_existing P0 | dba_troubleshooting.merges_eta |
| Frequent normalized query hash | new_item P0 | dba_troubleshooting.frequent_queries |
| Part creation errors | new_item P0 | optional dba_troubleshooting.part_log_errors |
| Number of tables by node | covered | cluster distribution items |
| Async insert activity | new_item P1 | deferred bounded historical item |
| Active parts / excessive partitions | extend_existing P0 | partition_part_counts with raw rows and threshold flag |
| Detached parts | covered | databases_objects.db_detached_parts |
| Memory by node from query history | new_item P1 | deferred peak/average item |
| Running queries cluster-wide | covered | activity.proc_current cluster variant |
| Replication queue summary | extend_existing P0 | one-shot summary plus snapshot queue chart |
P1/P2 work does not block the preview release. Before each minor release this map should be rechecked for new official candidates and duplication.