ClickHouse/docs/en/operations/system-tables/query_cache.md

slug
/en/operations/system-tables/query_cache

query_cache

Shows the content of the query cache.

Columns:

• query (String) — Query string.
• result_size (UInt64) — Size of the query cache entry.
• tag (LowCardinality(String)) — Tag of the query cache entry.
• stale (UInt8) — If the query cache entry is stale.
• shared (UInt8) — If the query cache entry is shared between multiple users.
• compressed (UInt8) — If the query cache entry is compressed.
• expires_at (DateTime) — When the query cache entry becomes stale.
• key_hash (UInt64) — A hash of the query string, used as a key to find query cache entries.

Example

SELECT * FROM system.query_cache FORMAT Vertical;

Row 1:
──────
query:       SELECT 1 SETTINGS use_query_cache = 1
result_size: 128
tag:
stale:       0
shared:      0
compressed:  1
expires_at:  2023-10-13 13:35:45
key_hash:    12188185624808016954

1 row in set. Elapsed: 0.004 sec.