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AdministeringIn addition to administering the database server, you can tune performance, replicate data, and archive data.
System administrationThese topics contain concepts, procedures, and reference information for database and database server administrators to use for managing and tuning HCL OneDB™ database servers.
Performance GuideThe HCL OneDB™ Performance Guide describes how to configure and operate your HCL OneDB™ database server to improve overall system throughput and to improve the performance of SQL queries.
Effect of configuration on I/O activityThe configuration of your database server affects I/O activity.
Background I/O activitiesBackground I/O activities do not service SQL requests directly. Many of these activities are essential to maintain database consistency and other aspects of database server operation. However, they create overhead in the CPU and take up I/O bandwidth.
Configuration parameters that affect page cleaningSeveral configuration parameters, including the CLEANERS and RTO_SERVER_RESTART configuration parameters, affect page cleaning. If pages are not cleaned often enough, an sqlexec thread that performs a query might be unable to find the available pages that it needs.
CLEANERS and its effect on page cleaningThe CLEANERS configuration parameter indicates the number of page-cleaner threads to run. For installations that support fewer than 20 disks, one page-cleaner thread is recommended for each disk that contains database server data. For installations that support between 20 and 100 disks, one page-cleaner thread is recommended for every two disks. For larger installations, one page-cleaner thread is recommended for every four disks.

CLEANERS and its effect on page cleaning

The CLEANERS configuration parameter indicates the number of page-cleaner threads to run. For installations that support fewer than 20 disks, one page-cleaner thread is recommended for each disk that contains database server data. For installations that support between 20 and 100 disks, one page-cleaner thread is recommended for every two disks. For larger installations, one page-cleaner thread is recommended for every four disks.

If you increase the number of LRU queues, you must increase the number of page-cleaner threads proportionally.