io_global_by_file_by_latency and x$io_global_by_file_by_latency Sys Schema Views

These views summarize global file I/O statistics grouped by file path, sorted by total latency to highlight slow I/O targets.

Sys Schema views are available from MariaDB 10.6.

Description

The io_global_by_file_by_latency and x$io_global_by_file_by_latency views summarize global I/O consumers to display time waiting for I/O, grouped by file. Rows are sorted by descending total latency by default.

The io_global_by_file_by_latency view is intended to be easier for human reading, while the x$io_global_by_file_by_latency view provides the data in raw form, intended for tools that process the data.

They contain the following columns:

Column	Description
file	File path name.
total	Total number of I/O events for the file.
total_latency	Total wait time of timed I/O events for the file.
count_read	Total number of read I/O events for the file.
read_latency	Total wait time of timed read I/O events for the file.
count_write	Total number of write I/O events for the file.
write_latency	Total wait time of timed write I/O events for the file.
count_misc	Total number of other I/O events for the file.
misc_latency	Total wait time of timed other I/O events for the file.

Example

SELECT * FROM sys.io_global_by_file_by_latency\G
*************************** 1. row ***************************
         file: @@datadir/ddl_recovery.log
        total: 222
total_latency: 288.64 ms
   count_read: 0
 read_latency: 0 ps
  count_write: 114
write_latency: 2.59 ms
   count_misc: 108
 misc_latency: 286.05 ms
*************************** 2. row ***************************
         file: @@datadir/ib_logfile0
        total: 95
total_latency: 165.29 ms
   count_read: 6
 read_latency: 61.04 us
  count_write: 43
write_latency: 1.31 ms
   count_misc: 46
 misc_latency: 163.92 ms
...

SELECT * FROM sys.x$io_global_by_file_by_latency\G
*************************** 1. row ***************************
         file: /home/ian/sandboxes/msb_10_6_19/data/ddl_recovery.log
        total: 222
total_latency: 288641408158
   count_read: 0
 read_latency: 0
  count_write: 114
write_latency: 2594925264
   count_misc: 108
 misc_latency: 286046482894
*************************** 2. row ***************************
         file: /home/ian/sandboxes/msb_10_6_19/data/ib_logfile0
        total: 95
total_latency: 165291020006
   count_read: 6
 read_latency: 61040974
  count_write: 43
write_latency: 1310187820
   count_misc: 46
 misc_latency: 163919791212
...

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