Overview

Used to view the metric information related to data cache on each BE node. The metric information is sourced from the monitoring metrics related to BE’s data cache.

tip

This system table is supported from versions 2.1.6 and 3.0.2.

Belongs to Database

information_schema

Table Information

Different Doris version may have different metrics

2.1.x Metrics

Only important metrics are listed.

• normal_queue_curr_elements

  Number of File Blocks currently in the cache.

• normal_queue_max_elements

  Maximum number of File Blocks allowed in the cache.

• normal_queue_curr_size

  Current cache size.

• normal_queue_max_size

  Maximum cache size allowed.

• hits_ratio

  Overall cache hit ratio since BE startup.

• hits_ratio_5m

  Cache hit ratio in the last 5 minutes.

• hits_ratio_1h

  Cache hit ratio in the last 1 hour.

3.0.x Metrics

TODO

Examples

1. Query all cache metrics

   mysql> select * from information_schema.file_cache_statistics;
   +-------+---------------+----------------------------+----------------------------+--------------------+
   | BE_ID | BE_IP         | CACHE_PATH                 | METRIC_NAME                | METRIC_VALUE       |
   +-------+---------------+----------------------------+----------------------------+--------------------+
   | 10003 | 172.20.32.136 | /mnt/output/be/file_cache/ | normal_queue_curr_elements |               1392 |
   | 10003 | 172.20.32.136 | /mnt/output/be/file_cache/ | normal_queue_curr_size     |          248922234 |
   | 10003 | 172.20.32.136 | /mnt/output/be/file_cache/ | normal_queue_max_elements  |             102400 |
   | 10003 | 172.20.32.136 | /mnt/output/be/file_cache/ | normal_queue_max_size      |        21474836480 |
   | 10003 | 172.20.32.136 | /mnt/output/be/file_cache/ | hits_ratio                 | 0.8539634687001242 |
   | 10003 | 172.20.32.136 | /mnt/output/be/file_cache/ | hits_ratio_1h              |                  0 |
   | 10003 | 172.20.32.136 | /mnt/output/be/file_cache/ | hits_ratio_5m              |                  0 |
   +-------+---------------+----------------------------+----------------------------+--------------------+

2. Query cache hit ratio and sort by hit ratio

   select * from information_schema.file_cache_statistics where METRIC_NAME = "hits_ratio" order by METRIC_VALUE desc;