Managing memory limitations

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You can ignore the memory limitation on Db2 Merge Backup tasks using Db2 Merge Backup configuration files.

Memory limitations on Db2 Merge Backup tasks

For the Db2 Merge Backup task running on the machine which it is launched from, the memory limitations that were applied by default were the "ulimit" ones applying to the associated shell. The MBKI473I message is sent in the execution report of any Db2 Merge Backup execution. This message shows the memory limitations applying to the associated task.

For the Db2 Merge Backup tasks started through Db2 Merge Backup deamons, the limitations applying to them were the "ulimit" ones of the user owning the intetd/xinetd utility, as thus the associated Db2 Merge Backup deamon. These limitations are automatically overridden by the ones of the original task started when launching Db2 Merge Backup, so that all the tasks involved in a given execution have the same limits applying to them: by default, the ones applying to the shell from which Db2 Merge Backup is launched, or unlimited values if the product is explicitly configured this way.

Allowing that memory limitation be ignored

By default, a given Db2 Merge Backup task is limited for its memory consumption by the "ulimit" values applying to the associated shell. It is now possible to allow that these limits be ignored.

Ignoring the memory limitations can be allowed by using a new configuration parameter of the db2mbk.cfg configuration file. This parameter is called allow_unlimited_memory and it can be set to yes or no, its default setting being no. Setting it to yes enables the ability of then choosing if a Db2 Merge Backup task can be executed without taking into account the current memory limitations.

Here is an example of its usage: 
...
allow_unlimited_memory=yes
...

Setting memory limitation to unlimited

When the previous configuration parameter has been set so that current memory limitations can be ignored, it is possible to decide that Db2 Merge Backup tasks be executed with these memory limitations set to unlimited.

This can be decided at a global level, by using a new configuration parameter of the db2mbk.cfg configuration file. This parameter is called memory_limit and it can be set to yes or no, its default setting being yes. Setting it to no allows that Db2 Merge Backup tasks running under its scope be executed with a memory limitations forced to unlimited.

Here is an example of its usage: 
...
memory_limit=no
...
If the option of setting this ability globally is not suitable, it can be applied to specific executions only, by using a new command line option, which is offering the same capability. Specifying this ability in the command line is overriding any setting of this kind made in a configuration file. This command line option syntax is the following one:
-memory-limit no\yes
.