file_cache_info

Overview

The file_cache_info system table exposes block-level File Cache entries on all alive BE nodes. Use it to analyze cache space by tablet, BE, cache path, or cache type, and to investigate cache skew or unexpected cache growth.

Version

This system table is supported in Doris 4.1 and later. It is not available in Doris 4.0.x.

Each row represents one cached block. The result reflects the current cache state and can change while queries populate or evict cache entries.

caution

Querying this table scans persisted File Cache metadata on the selected BE nodes and can generate additional I/O when the cache contains many blocks. Avoid frequent unfiltered queries. Filter by BE_ID when you only need data from specific BE nodes.

Database

information_schema

Table Information

Column Name	Type	Description
HASH	STRING	Hash of the remote file to which the cached block belongs.
OFFSET	BIGINT	Starting offset of the cached block in the remote file, in bytes.
TABLET_ID	BIGINT	ID of the tablet associated with the cached block. The value is 0 when the block is not associated with a tablet.
SIZE	BIGINT	Size of the cached block, in bytes.
TYPE	STRING	Cache type. Possible values are normal, index, ttl, and disposable.
REMOTE_PATH	STRING	Reserved for the remote file path. Currently returns an empty string.
CACHE_PATH	STRING	Local File Cache root path on the BE node.
BE_ID	BIGINT	ID of the BE node that stores the cached block.

Examples

Query the cache entries of a tablet

SELECT *
FROM information_schema.file_cache_info
WHERE TABLET_ID = 1761571031445;

+----------------------------------+--------+---------------+-------+-------+-------------+------------------------------+---------------+
| HASH                             | OFFSET | TABLET_ID     | SIZE  | TYPE  | REMOTE_PATH | CACHE_PATH                   | BE_ID         |
+----------------------------------+--------+---------------+-------+-------+-------------+------------------------------+---------------+
| 468448215c52334ae5bee147259b1027 |      0 | 1761571031445 | 15120 | index |             | /mnt/disk1/project/filecache | 1761571031251 |
| 71bb73d34cd8ffe280b16dd329df5ba1 |  15120 | 1761571031445 | 13117 | index |             | /mnt/disk1/project/filecache | 1761571031251 |
| 77c6b69d1a7c4fe740a11bab5c1bbaa3 |  28237 | 1761571031445 | 12249 | index |             | /mnt/disk1/project/filecache | 1761571031251 |
+----------------------------------+--------+---------------+-------+-------+-------------+------------------------------+---------------+

Summarize cache usage

The following query summarizes the cache space occupied by a tablet on each BE and for each cache type:

SELECT BE_ID, TABLET_ID, TYPE, SUM(SIZE) AS CACHE_BYTES
FROM information_schema.file_cache_info
WHERE TABLET_ID = 1761571031445
GROUP BY BE_ID, TABLET_ID, TYPE
ORDER BY CACHE_BYTES DESC;

+---------------+---------------+-------+-------------+
| BE_ID         | TABLET_ID     | TYPE  | CACHE_BYTES |
+---------------+---------------+-------+-------------+
| 1761571031251 | 1761571031445 | index |       40486 |
+---------------+---------------+-------+-------------+