Updated on 2023-10-23 GMT+08:00

GS_WLM_INSTANCE_HISTORY

GS_WLM_INSTANCE_HISTORY stores information about resource usage related to CNs or DNs. Each record in this system catalog indicates resource usage of an instance at a specific time point, including the memory, number of CPU cores, disk I/O, physical I/O of the process, and logical I/O of the process. This system catalog can be queried by users with the sysadmin permission only in Postgres.

Table 1 GS_WLM_INSTANCE_HISTORY columns

Name

Type

Description

instancename

text

Instance name

timestamp

timestamp with time zone

Timestamp

used_cpu

integer

CPU usage of the instance

free_mem

integer

Unused memory of the instance, in MB

used_mem

integer

Used memory of the instance, in MB

io_await

real

Average wait time for an I/O operation on the disk used by the instance. The average value is within 10 seconds.

io_util

real

io_util value of the disk used by the instance. The average value is within 10 seconds.

disk_read

real

Disk read rate of the instance, in KB/s. The average value is within 10 seconds.

disk_write

real

Disk write rate of the instance, in KB/s. The average value is within 10 seconds.

process_read

bigint

Read rate (excluding the number of bytes read from the disk pagecache) of the corresponding instance process that reads data from a disk within 10 seconds, in KB/s

process_write

bigint

Write rate (excluding the number of bytes written to the disk pagecache) of the corresponding instance process that writes data to a disk within 10 seconds, in KB/s

logical_read

bigint

CN: N/A

DN: logical read byte rate of the instance within the statistical interval (10 seconds), in KB/s

logical_write

bigint

CN: N/A

DN: logical write byte rate of the instance within the statistical interval (10 seconds), in KB/s

read_counts

bigint

CN: N/A

DN: total number of logical read operations of the instance within the statistical interval (10 seconds)

write_counts

bigint

CN: N/A

DN: total number of logical write operations of the instance within the statistical interval (10 seconds)