My SQL queries in ClickHouse are suddenly running much slower than they did yesterday, what troubleshooting steps should I check first in the system logs?
Download run
Fan-out diagram
The searches the AI actually ran for this prompt.
SEED QUERY
My SQL queries in ClickHouse are suddenly running much slower than they did yesterday, what troubleshooting steps should I check first in the system logs?
1 real search · 1 real-search pass
ClickHouse official documentation system.query_log system.metrics asynchronous_metrics system.parts merges logs troubleshooting performanceGoogle ↗
OBSERVED
Badge and edge weight = share of passes that produced the query. Hover a query for its intent and routing format.
Query classes
Google's semantic query class for every sub-query: what kind of answer each search is after, simulated vs real.
Classifying 1 queries…
Searches and sources
ChatGPT1 real searches · gpt-6
ClickHouse official documentation system.query_log system.metrics asynchronous_metrics system.parts merges logs troubleshooting performance Google ↗
- clickhouse-docs/knowledgebase/useful-queries-for-troubleshooting.mdx at main · ClickHouse/clickhouse-docs · github.com
- System Tables and a Window into the Internals of ClickHouse · clickhouse.com
- Top 10 best practices tips for ClickHouse · clickhouse.com
- The definitive guide to ClickHouse query optimization (2026) | Engineering | ClickHouse Resource Hub · clickhouse.com
- A simple guide to ClickHouse query optimization: part 1 · clickhouse.com