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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.
Administrator's ReferenceThe HCL OneDB™ Administrator's Reference includes comprehensive descriptions of HCL OneDB™ configuration parameters, the system-monitoring interface (SMI) tables in the sysmaster database, the syntax of database server utilities such as onmode and onstat, logical-log records, disk structures, event alarms, and unnumbered error messages.
Configuring and monitoring HCL OneDB™
Database configuration parametersThe HCL OneDB™ database server uses a configuration file, which is called the onconfig file, during initialization. This file contains default configuration parameter values. You can modify the parameter values to improve performance and other characteristics of the instance or database.
OFF_RECVRY_THREADS configuration parameterUse the OFF_RECVRY_THREADS configuration parameter to specify the number of recovery threads that are used for logical recovery during a cold restore or fast recovery.

OFF_RECVRY_THREADS configuration parameter

Use the OFF_RECVRY_THREADS configuration parameter to specify the number of recovery threads that are used for logical recovery during a cold restore or fast recovery.

onconfig.std value: OFF_RECVRY_THREADS 10
values: Positive integers
units: Number of recovery threads that run in parallel
takes effect: After you edit your onconfig file and restart the database server.

Usage

Before you perform a cold restore, you can set the value of this parameter to approximately the number of tables that have many transactions against them in the logical log. For single-processor computers or nodes, more than 30 to 40 threads might be too many because the cost of thread management and memory offsets the increase in parallel processing.

Whenever logical recovery begins, the database server creates an LGR memory pool for the recovery threads. The size of the LGR memory pool is approximately equal to the value of OFF_RECVRY_THREADS * 100 KB. This pool is used during fast recovery and during cold restores. Do not set the OFF_RECVRY_THREADS configuration parameter to a value that results in the database server attempting to allocate more memory for the LGR memory pool than is available on your system.

In a high-availability cluster, a secondary server is almost always in fast recovery mode. On secondary servers, set the OFF_RECVRY_THREADS configuration parameter to a value that takes both roll-forward performance and memory usage into account.

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