Updated at: 2022-08-03 GMT+08:00

GS_WLM_INSTANCE_HISTORY

The GS_WLM_INSTANCE_HISTORY system catalog stores information about resource usage related to CN or DN instances. Each record in the system table indicates the 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.

Table 1 GS_WLM_INSTANCE_HISTORY column

Name

Type

Description

instancename

text

Instance name

timestamp

timestamp with time zone

Timestamp

used_cpu

int

CPU usage of an instance

free_mem

int

Unused memory of an instance (unit: MB)

used_mem

int

Used memory of an instance (unit: MB)

io_await

real

Specifies the io_wait value (average value within 10 seconds) of the disk used by an instance.

io_util

real

Specifies the io_util value (average value within 10 seconds) of the disk used by an instance.

disk_read

real

Specifies the disk read rate (average value within 10 seconds) of an instance (unit: KB/s).

disk_write

real

The disk write rate (average value within 10 seconds) of an instance (unit: KB/s).

process_read

bigint

Specifies the read rate (excluding the number of bytes read from the disk pagecache) of the corresponding instance process that reads data from a disk. (Unit: KB/s)

process_write

bigint

Specifies the 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. (Unit: KB/s)

logical_read

bigint

CN instance: N/A

DN instance: Specifies the logical read byte rate of the instance in the statistical interval (10 seconds). (Unit: KB/s)

logical_write

bigint

CN instance: N/A

DN instance: Specifies the logical write byte rate of the instance within the statistical interval (10 seconds). (Unit: KB/s)

read_counts

bigint

CN instance: N/A

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

write_counts

bigint

CN instance: N/A

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

close