The alterdb command specifies the initial journal size in the format:

where n is a number of blocks from 0 to the current target journal size (which can be obtained using infodb). Only one database name is required. The -init_jnl_blocks=n option allows a measure of control over when journal file disk space allocation takes place, but only for the first journal file created after a ckpdb command.

This alterdb command can be issued at any time, and takes effect when the next database journal file is created. In the case of an offline checkpoint, this can be some time after the ckpdb command is issued. In the case of an online checkpoint, the file allocation occurs during execution of the checkpoint.

Upon successful completion of this command, a message is written to the errlog.log. The updated block value can be observed as the infodb “Initial journal size.”