Database Administrator's Guide

DYNAMIC_DUMP_DEFER

DYNAMIC_DUMP_DEFER <milliseconds>

When a dynamic dump runs, the disk read and write operations of the backup process can slow the performance of other database operations. This option allows an administrator to reduce the performance impact of the dynamic dump.

milliseconds is the time that the dynamic dump thread will sleep after each write of a 64KB block of data to the dump backup file.

An application developer can also use the c-tree ctSETCFG() API function to set the DYNAMIC_DUMP_DEFER value. For example, the following call specifies a 10-millisecond DYNAMIC_DUMP_DEFER time:

ctSETCFG( setcfgDYNAMIC_DUMP_DEFER, "10" );

The DYNAMIC_DUMP_DEFER value set by a call to ctSETCFG() takes effect immediately, so this API call can be used by administrators to adjust the speed of a running dynamic dump depending on the amount of other database activity.

Note: The maximum allowed DYNAMIC_DUMP_DEFER time is 5000 milliseconds, set at compile-time. If a value is specified that exceeds this limit, the DYNAMIC_DUMP_DEFER time is set to DYNAMIC_DUMP_DEFER_MAX.

The FairCom DB Administrator utility, ctadmn, was also updated to support the dump sleep time option to change this value at run time. The "Change Server Settings" menu is available from the main menu of the ctadmn utility.