AL02 does not exist now i mean this transaction was used earlier by the users as SAP Alert Monitor. so that they can setup alerts to monitor the system.
Instead of this transaction now a days through RZ20, CCMS agents monitors the system and collects the data of the system.
Where St04 is related to database, basically it's database performance overview. Any information related to database can be found here like top growing tables, jobs, expensive sql etc.
Hope this helps!!
Thanks and Regards
AL02 is used as SAP Alert Monitor. You can setup alerts to monitor your system.
But now a days we are not using AL02. We are using RZ20 to set up CCMS monitor alerts.
ST02 gives you Tune summary. There you can find out all details about Memory parameters & all buffers. It highlights swaps in your system. You can also switch to other transactions also like Database performance, OS06 etc.
So ST02 is really very helpful monitoring transaction. Generally used to monitor system swaps & other buffer parameters
Hope you can get idea..