Hi Ruben,
The question here would be: why do you need to enable the truncate log on checkpoint on your SID database ?
You have a risk with enabling that parameter: your last database backup + transaction log backup won't allow you to restore completely your environment if any disaster situation (please check the Note 1585981 - SYB: Ensuring Recoverability for SAP ASE.
But about your question: the "truncat log on ckpt" is used if you don't want to keep backup of the transaction log, that is, no dump transaction can be performed.
When we enable that database option, the transaction log will be truncated (that is, committed transactions are removed from the log) when automatic checkpoint is done (more or less once a minute), a manual checkpoint (with command "checkpoint") won't truncate the transaction log.
But again, that database option shouldn't be enable for your SID, you'll find this on SAP Note 1581695 - SYB: Configuration Guide for SAP ASE 16.0 :
> trunc log on chkpt = 0 [REQ; S:@SID]
Regards,
Victoria.