The disk_write_speed_aggregate table provides
aggregated information about the speed of disk writes during
LCP, backup, and restore operations.
The following table provides information about the columns in
the disk_write_speed_aggregate table in NDB
7.4.3 and later; information about
disk_write_speed_aggregate in NDB 7.4.2 and
earlier can be found later in this section. For each column, the
table shows the name, data type, and a brief description.
Additional information can be found in the notes following the
table.
| Column Name | Type | Description |
|---|---|---|
| node_id | integer | Node ID of this node |
| thr_no | integer | Thread ID of this LDM thread |
| backup_lcp_speed_last_sec | integer | Number of bytes written to disk by backup and LCP processes in the last second |
| redo_speed_last_sec | integer | Number of bytes written to REDO log in the last second |
| backup_lcp_speed_last_10sec | integer | Number of bytes written to disk by backup and LCP processes per second, averaged over the last 10 seconds |
| redo_speed_last_10sec | integer | Number of bytes written to REDO log per second, averaged over the last 10 seconds |
| std_dev_backup_lcp_speed_last_10sec | integer | 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 | integer | Standard deviation in number of bytes written to REDO log per second, averaged over the last 10 seconds |
| backup_lcp_speed_last_60sec | integer | Number of bytes written to disk by backup and LCP processes per second, averaged over the last 60 seconds |
| redo_speed_last_60sec | integer | Number of bytes written to REDO log per second, averaged over the last 10 seconds |
| std_dev_backup_lcp_speed_last_60sec | integer | 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 | integer | Standard deviation in number of bytes written to REDO log per second, averaged over the last 60 seconds |
| slowdowns_due_to_io_lag | integer | Number of seconds that disk writes were slowed due to REDO log I/O lag |
| slowdowns_due_to_high_cpu | integer | Number of seconds that disk writes were slowed due to high CPU usage |
| disk_write_speed_set_to_min | integer | Number of seconds that disk write speed was set to minimum |
| current_target_disk_write_speed | integer | 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. (Bug #74317, Bug
#19795072) The following table provides information about
disk_write_speed_aggregate as implemented
previously.
| Column Name | Type | Description |
|---|---|---|
| node_id | integer | Node ID of this node |
| thr_no | integer | Thread ID of this LDM thread |
| backup_lcp_speed_last_sec | integer | Number of kilobytes written to disk by backup and LCP processes in the last second |
| redo_speed_last_sec | integer | Number of kilobytes written to REDO log in the last second |
| backup_lcp_speed_last_10sec | integer | Number of kilobytes written to disk by backup and LCP processes per second, averaged over the last 10 seconds |
| redo_speed_last_10sec | integer | Number of kilobytes written to REDO log per second, averaged over the last 10 seconds |
| std_dev_backup_lcp_speed_last_10sec | integer | 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 | integer | Standard deviation in number of kilobytes written to REDO log per second, averaged over the last 10 seconds |
| backup_lcp_speed_last_60sec | integer | Number of kilobytes written to disk by backup and LCP processes per second, averaged over the last 60 seconds |
| redo_speed_last_60sec | integer | Number of kilobytes written to REDO log per second, averaged over the last 10 seconds |
| std_dev_backup_lcp_speed_last_60sec | integer | 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 | integer | Standard deviation in number of kilobytes written to REDO log per second, averaged over the last 60 seconds |
| slowdowns_due_to_io_lag | integer | Number of seconds since last node start that disk writes were slowed due to REDO log I/O lag |
| slowdowns_due_to_high_cpu | integer | Number of seconds since last node start that disk writes were slowed due to high CPU usage |
| disk_write_speed_set_to_min | integer | Number of seconds since last node start that disk write speed was set to minimum |
| current_target_disk_write_speed | integer | Actual speed of disk writes per LDM thread (aggregated) |
The disk_write_speed_aggregate table was
added in NDB 7.4.1.