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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)