LOGSIZE configuration parameter

Use the LOGSIZE configuration parameter to specify the size that is used when logical-log files are created.

onconfig.std value
LOGSIZE 10000
units
Kilobytes
values
An integer value.

Minimum value = 200

Maximum value when the database server is first initialized = (ROOTSIZE - PHYSFILE - 512 - (63 * pagesize/1024)) / LOGFILES

The pagesize value is the default system page size for the operating system.

If you expand the root dbspace or move logical logs to a different dbspace, the maximum size of logical log files cannot exceed the following page size-dependent value:
  • 1 GiB for page size = 2 KiB
  • 2 GiB for page size = 4 KiB
This limit is the maximum number of pages that the log position can describe for those page sizes.
takes effect
After you edit your onconfig file and restart the database server.
When you reset the value dynamically in your onconfig file by running the onmode -wf command.
When you reset the value in memory by running the onmode -wm command.

Usage

When you change the value of the LOGSIZE configuration parameter, only new log files are affected. The size of existing log files does not change. The total logical-log size is the product of the LOGSIZE configuration parameter setting multiplied by the value of the LOGFILES configuration parameter. However, if you change the value of the LOGSIZE configuration parameter, the total size of all logical log files depends on the number of log files of each size.

If the AUTO_LLOG configuration parameter is enabled, logical log files are added automatically as needed to improve performance, up to a configurable maximum total logical-log size.

To verify the page size that the database server uses on your platform, run the onstat -b command.

If you declare logging for a smart-large-object column, you must ensure that the logical log is considerably larger than the amount of data that is logged during inserts or updates. The database server cannot back up open transactions. If many transactions are active, the total logging activity must not force open transactions to the log backup files. For example, if your log size is 1000 KB and the high-watermark is 60 percent, do not use more than 600 KB of the logical log for the smart-large-object updates. The database server starts rolling back the transaction when it reaches the high-watermark of 600 KB.


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