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)