ClickHouse/docs/en/operations/caches.md

Ignoring revisions in .git-blame-ignore-revs. Click here to bypass and see the normal blame view.

27 lines
1.0 KiB
Markdown
Raw Normal View History

2021-01-16 20:00:00 +00:00
---
2022-08-28 14:53:34 +00:00
slug: /en/operations/caches
sidebar_position: 65
sidebar_label: Caches
2022-08-29 16:19:50 +00:00
title: "Cache Types"
2021-01-16 20:00:00 +00:00
---
2022-05-31 15:46:53 +00:00
When performing queries, ClickHouse uses different caches.
2021-01-16 20:00:00 +00:00
Main cache types:
2021-01-16 20:00:00 +00:00
- `mark_cache` — Cache of marks used by table engines of the [MergeTree](../engines/table-engines/mergetree-family/mergetree.md) family.
- `uncompressed_cache` — Cache of uncompressed data used by table engines of the [MergeTree](../engines/table-engines/mergetree-family/mergetree.md) family.
- Operating system page cache (used indirectly, for files with actual data).
2021-01-16 20:00:00 +00:00
Additional cache types:
- DNS cache.
- [Regexp](../interfaces/formats.md#data-format-regexp) cache.
- Compiled expressions cache.
- [Avro format](../interfaces/formats.md#data-format-avro) schemas cache.
- [Dictionaries](../sql-reference/dictionaries/index.md) data cache.
- Schema inference cache.
2022-09-07 11:04:44 +00:00
- [Filesystem cache](storing-data.md) over S3, Azure, Local and other disks.
2021-01-16 20:00:00 +00:00
2022-12-01 22:52:50 +00:00
To drop one of the caches, use [SYSTEM DROP ... CACHE](../sql-reference/statements/system.md#drop-mark-cache) statements.