mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-27 10:02:01 +00:00
37 lines
1.3 KiB
Markdown
37 lines
1.3 KiB
Markdown
|
---
|
||
|
|
slug: /en/operations/system-tables/query_cache
|
||
|
|
---
|
||
|
|
# query_cache
|
||
|
|
|
||
|
|
Shows the content of the [query cache](../query-cache.md).
|
||
|
|
|
||
|
|
Columns:
|
||
|
|
|
||
|
|
- `query` ([String](../../sql-reference/data-types/string.md)) — Query string.
|
||
|
|
- `result_size` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Size of the query cache entry.
|
||
|
|
- `stale` ([UInt8](../../sql-reference/data-types/int-uint.md)) — If the query cache entry is stale.
|
||
|
|
- `shared` ([UInt8](../../sql-reference/data-types/int-uint.md)) — If the query cache entry is shared between multiple users.
|
||
|
|
- `compressed` ([UInt8](../../sql-reference/data-types/int-uint.md)) — If the query cache entry is compressed.
|
||
|
|
- `expires_at` ([DateTime](../../sql-reference/data-types/datetime.md)) — When the query cache entry becomes stale.
|
||
|
|
- `key_hash` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — A hash of the query string, used as a key to find query cache entries.
|
||
|
|
|
||
|
|
**Example**
|
||
|
|
|
||
|
|
``` sql
|
||
|
|
SELECT * FROM system.query_cache FORMAT Vertical;
|
||
|
|
```
|
||
|
|
|
||
|
|
``` text
|
||
|
|
Row 1:
|
||
|
|
──────
|
||
|
|
query: SELECT 1 SETTINGS use_query_cache = 1
|
||
|
|
result_size: 128
|
||
|
|
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.
|
||
|
|
```
|