Product Documentation

Database Administrator's Guide

Previous Topic

Next Topic


TRAN_DATA_FLUSH_SEC <time_limit_in_seconds>

Sets the time limit in seconds that a data cache page can remain dirty before it is written to the file system cache.

  • Specify IMMEDIATE to cause dirty pages to be written immediately.
  • Specify OFF or -1 to disable the time limit-based flushing.
  • In V11.4 and later, a rate limiting parameter can be specified as follows: "rate=<msec> / <number of flushes>"
    For example, to defer for 1 millisecond after every two flushes of updated TRNLOG data cache pages, use this option:
    TRAN_DATA_FLUSH_SEC rate=1/2

System snapshot 19 and later includes fields referencing background flush state structure, BGFLSS, which is in the system snapshot structure, ctGSMS. When a background flush thread is set to flush at a particular rate, the text snapshot shows the rate. For example:

time limit for dirty non-transaction data pages : rate=1/1

This option can be changed using the ctSETCFG() API function or the ctadmn utility.

Note: Enabling this option disables checkpoint flush operations.

Default: -1 (disabled)

See Also