MySQL 5.6 Reference Manual Including MySQL NDB Cluster 7.3-7.4 Reference Guide
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 in NDB
7.4.3 and later 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)
Prior to NDB 7.4.3, the standard deviation used in obtaining the
values shown in the
std_dev_backup_lcp_speed_last_10sec,
std_dev_redo_speed_last_10sec,
std_dev_backup_lcp_speed_last_60sec, and
std_dev_redo_speed_last_60sec columns of this
table was not calculated correctly. (Bug #74317, Bug #19795072)
Prior to NDB 7.4.3, some columns of this table showed values in kilobytes or other multiples of bytes. (In NDB 7.4.3 and later, all such columns display values in bytes, as shown previously.) (Bug #74317, Bug #19795072) In NDB 7.4.2 and earlier, this table contained 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 kilobytes written to disk by backup and LCP processes in the last second
redo_speed_last_sec
Number of kilobytes written to REDO log in the last second
backup_lcp_speed_last_10sec
Number of kilobytes written to disk by backup and LCP processes per second, averaged over the last 10 seconds
redo_speed_last_10sec
Number of kilobytes written to REDO log per second, averaged over the last 10 seconds
std_dev_backup_lcp_speed_last_10sec
Standard deviation in number of kilobytes 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 kilobytes written to REDO log per second, averaged over the last 10 seconds
backup_lcp_speed_last_60sec
Number of kilobytes written to disk by backup and LCP processes per second, averaged over the last 60 seconds
redo_speed_last_60sec
Number of kilobytes written to REDO log per second, averaged over the last 10 seconds
std_dev_backup_lcp_speed_last_60sec
Standard deviation in number of kilobytes 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 kilobytes 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)
The disk_write_speed_aggregate table was
added in NDB 7.4.1.