Hi,
first, let me say that I cannot offer a solution for your specific question of what has caused the sporadic temp space increase.
But some general thoughts from my side:
1. 'Database Studio' displays the 'command monitor' and 'resource monitor' data (but these can cause some performance drop in 7.5). But this is not an option here since MaxDB 7.5 is not supported by Database Studio.
2. If you have a R/3 system available, I would suggest to integrate that JAVA system into the CCMS monitoring (see SAP FAQ note 990602, question 8 & 9). This way you could work with the resource and command monitor plus you would get the Database Analyzer data displayed much easier to read and you could even aggregate that data to show you daily or monthly aggregates...
Database Analyzer also shows the temp space usage in one of the 'Expert View' files. The Analyzer per default collects data every 15 minutes, but you might want to shorten the interval to 60 seconds for more accurate data. Still, in MaxDB 7.9 the Database analyzer is more sophisticated and can collect more statistics, because the Database monitoring in MaxDB has been improved...
3. If this is a SAP system, you could also open a SAP ticket for assistance.
4. It might be worth a try to let 'x_cons' run while the database is starting and you suspect the temp space increasing. You can configure x_cons to run as 'x_cons <dbname> show tasks 60 60 > out.txt' and it would collect the task states of all tasks at an interval of 60 seconds with a total of 60 calls (which results in one hour runtime...). This would not show you the cause of increasing temp space, but give you a better overview of what happens at task level at that time.
Thorsten