Starting and Stopping Databases

On occasion, DBAs may need to either start up or shut down their databases. Sometimes it's to forcibly clean up hung or locked server processes. Other times it's to simply effect INIT.ORA parameter file modifications. And some DBAs just like to cycle their databases every now and then because they believe it's good preventive medicine. Whatever the reasons, TOAD can do both database startups and shutdowns via the Instance Manager screen accessible from the main menu at DBAInstance Manager (this screen was also covered in the preceding chapter for the monitoring of your databases).

Figure 6.8 shows TOAD being utilized to shut down a database. One thing happening behind the scenes that later seems to cause some confusion is that TOAD makes a copy of the current Oracle instance parameter settings in the TOAD install directory under the DBA subdirectory. Many TOAD users are only accustomed to working with local databases, and thus this step seems useless (because the INIT.ORA file for local database is already available). But TOAD must also work for DBAs who manage remote databases, whose INIT.ORA files are not on their local PC. So TOAD makes a copy of the settings so that it can start what it stops. By the way, this is exactly how Oracle's Enterprise Manager (OEM) works as well. OEM creates a file under the sysman\ifiles directory.

Figure 6.8. TOAD Instance Manager ”Shutdown Database.

Figure 6.9 shows TOAD being utilized to start up a database. See the option to specify a parameter file? Again, for people working with local databases, you could use either the TOAD-created file or the actual INIT.ORA file on your PC. For people working with remote databases, the only option you have is the TOAD-created parameter file. Note that if you choose a startup level less than open, the Instance Manager screen's Alter button will enable. This would be useful if you wanted to do a startup mount in order to do some recovery tasks , and then later needed to open the database for normal operations.

Figure 6.9. TOAD Instance Manager ”Startup Database.

There is one final issue and it is important to consider when using TOAD for database startups and shutdowns. If you always use TOAD for all database startups and shutdowns, you should never have any problems where parameter settings are an issue. But if you mix methods and tools for doing database startups and shutdowns, you may well run into problems. For example, assume that the database is up, you change some dynamic parameters, and then use TOAD to shut down the database. If you now do a database startup using some other tool such as OEM or SQL*Plus, you'll lose the dynamic parameter modifications you made that were saved in the TOAD parameter file. This scenario would fail using OEM and then SQL*Plus in exactly the same way. Thus this is not a TOAD problem, but merely shows that doing database startups and shutdowns requires consistent methodology in order to avoid such problems. Of course, most DBA tasks should have consistent rules governing their execution for best results.