host_summary_by_file_io_type and x$host_summary_by_file_io_type Sys Schema Views

These views provide a breakdown of file I/O events by event type (e.g., read, write) for each host, helping to characterize the I/O workload.

Sys Schema views are available from MariaDB 10.6.

Description

The host_summary_by_file_io_type and x$host_summary_by_file_io_type views summarize file I/O, grouped by host and event type. Rows are sorted by host and descending total I/O latency by default. The host_summary_by_file_io_type view is intended to be easier for human reading, while the x$host_summary_by_file_io_type view provides the data in raw form, intended for tools that process the data.

They contain the following columns:

Column	Description
host	Host that the client connected from, or background for background threads (where the HOST column in the underlying Performance Schema table is NULL).
event_name	File I/O event name.
total	Total number of occurrences of the file I/O event for the host.
total_latency	Total wait time of timed occurrences of the file I/O event for the host.
max_latency	Maximum single wait time of timed occurrences of the file I/O event for the host.

Example

SELECT * FROM sys.host_summary_by_file_io_type;
+------------+----------------------------------------------+-------+---------------+-------------+
| host       | event_name                                   | total | total_latency | max_latency |
+------------+----------------------------------------------+-------+---------------+-------------+
| background | wait/io/file/innodb/innodb_log_file          |    45 | 109.80 ms     | 26.48 ms    |
| background | wait/io/file/innodb/innodb_data_file         |   195 | 29.47 ms      | 1.23 ms     |
| background | wait/io/file/sql/global_ddl_log              |     4 | 4.45 ms       | 4.33 ms     |
...
| localhost  | wait/io/file/csv/data                        |     4 | 25.98 us      | 9.60 us     |
| localhost  | wait/io/file/partition/ha_partition::parfile |     1 | 14.19 us      | 14.19 us    |
| localhost  | wait/io/file/myisam/kfile                    |     1 | 11.95 us      | 11.95 us    |
+------------+----------------------------------------------+-------+---------------+-------------+

SELECT * FROM sys.x$host_summary_by_file_io_type;
+------------+----------------------------------------------+-------+---------------+-------------+
| host       | event_name                                   | total | total_latency | max_latency |
+------------+----------------------------------------------+-------+---------------+-------------+
| background | wait/io/file/innodb/innodb_log_file          |    45 |  109804643160 | 26478157582 |
| background | wait/io/file/innodb/innodb_data_file         |   195 |   29469738630 |  1226986584 |
| background | wait/io/file/sql/global_ddl_log              |     4 |    4447263252 |  4327780456 |
| localhost  | wait/io/file/csv/data                        |     4 |      25978718 |     9603922 |
| localhost  | wait/io/file/partition/ha_partition::parfile |     1 |      14191190 |    14191190 |
| localhost  | wait/io/file/myisam/kfile                    |     1 |      11954300 |    11954300 |
+------------+----------------------------------------------+-------+---------------+-------------+

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