21.6.15.18 The ndbinfo disk_write_speed_aggregate Table

The disk_write_speed_aggregate table provides aggregated information about the speed of disk writes during LCP, backup, and restore operations.

The disk_write_speed_aggregate table contains the following columns:

node_id

Node ID of this node
thr_no

Thread ID of this LDM thread
backup_lcp_speed_last_sec

Number of bytes written to disk by backup and LCP processes in the last second
redo_speed_last_sec

Number of bytes written to REDO log in the last second
backup_lcp_speed_last_10sec

Number of bytes written to disk by backup and LCP processes per second, averaged over the last 10 seconds
redo_speed_last_10sec

Number of bytes written to REDO log per second, averaged over the last 10 seconds
std_dev_backup_lcp_speed_last_10sec

Standard deviation in number of bytes written to disk by backup and LCP processes per second, averaged over the last 10 seconds
std_dev_redo_speed_last_10sec

Standard deviation in number of bytes written to REDO log per second, averaged over the last 10 seconds
backup_lcp_speed_last_60sec

Number of bytes written to disk by backup and LCP processes per second, averaged over the last 60 seconds
redo_speed_last_60sec

Number of bytes written to REDO log per second, averaged over the last 10 seconds
std_dev_backup_lcp_speed_last_60sec

Standard deviation in number of bytes written to disk by backup and LCP processes per second, averaged over the last 60 seconds
std_dev_redo_speed_last_60sec

Standard deviation in number of bytes written to REDO log per second, averaged over the last 60 seconds
slowdowns_due_to_io_lag

Number of seconds since last node start that disk writes were slowed due to REDO log I/O lag
slowdowns_due_to_high_cpu

Number of seconds since last node start that disk writes were slowed due to high CPU usage
disk_write_speed_set_to_min

Number of seconds since last node start that disk write speed was set to minimum
current_target_disk_write_speed

Actual speed of disk writes per LDM thread (aggregated)