Checking Status of All Your Instances

One of the most important and routine tasks any DBA does is to check the status of their databases. In fact, what they really want to visually and very quickly ascertain is which:

• Servers are down

• Listeners are down

• Instances are down

Of course, you could wait for the phone to ring or your pager to go off. But it is infinitely more desirable to have a compact and focused way to easily verify all this information. So TOAD provides the Instance Manager screen, which is located on the main menu at DBA, Instance Manager and depicted in Figure 5.1.

Figure 5.1. TOAD Instance Manager screen.

With this one screen, the DBA can quickly see the status of all their database servers, listeners, and instances. If all is well, the Node, Listener, and Database (that is, database instance) cells in the grid displayed on the Status tab will all contain green check marks. If there are any problems, the cells will contain red X's. While the screen is checking for the first time, the cells will contain a red question mark inside a yellow circle. Of course, the goal is to always see all green check marks, as shown in Figure 5.1, meaning that all is well.

One option on this screen that seems to cause minor confusion is the Polling Priority drop-down list. Contrary to common and incorrect belief, polling priority has absolutely nothing to do with your database server. TOAD performs Instance Manager monitoring by creating a Windows background execution thread on your client PC. This drop-down list merely enables you to assign that thread's execution priority. The valid priorities include idle (will only refresh when no other Windows task is running), lowest , lower, normal, higher, highest, and time-critical. If you intend to keep an Instance Manager screen up at all times, the recommendation is to choose a setting of normal or below (the default is lower).

This screen also offers two other very useful DBA functions. First, you can create an INIT.ORA text file with the actual parameter values currently set for that database instance by using the Build Init.Ora button. This would be very useful if you've modified parameter values that are session-modifiable. And second, you can start up, alter, or shut down a database instance by using the Startup, Shutdown, and Alter buttons . So in essence, you can both monitor and control all your database instances from the Instance Manager screen.

Note that there are many options within TOAD related to using the Instance Manager screen, shown in Figures 5.2, 5.3, and 5.4. The TOAD Options screen can be opened either by using the Toolbox icon on the main toolbar or from the main menu at View, Options.

Figure 5.2. TOAD General Options for Instance Manager.

Figure 5.3. TOAD Email Settings options for Instance Manager.

Figure 5.4. TOAD Startup Options for Instance Manager.

Figure 5.1 shows the options category for Instance Manager. You can select which servers to poll and also which servers to post alerts for when they are down. Alerts exhibit themselves in one of two ways: by animating the TOAD tray icon and/or through e-mail messages. Did you notice in Figure 5.1 the TOAD tray icon, which appeared in the lower right-hand corner of the screen? When this option is enabled and a database selected for alerts has problems, the TOAD tray icon will animate. Likewise, if the Enable Email Alerts check box is checked, TOAD will e-mail an appropriate alert message. However, for this to work, you must visit the options category for Email Settings and define all the appropriate information as depicted in Figure 5.3.

One of the most important and routine tasks any DBA does is to check the status of their databases. So this is most likely one of the first things a DBA would want to do when they start their daily, morning routine. Therefore, wouldn't it be useful if TOAD would automatically open this screen when it launched? You can choose that option in the TOAD Options category for DBA as shown in Figure 5.4. You just need to check the box for Open an Instance Manager at Startup. Now TOAD will automatically launch this window, as well as any others indicated under the options category for Startup.

Notice that in Figure 5.4, the check box for Refresh Instance Manager Database Version During Every Poll is not checked. Because it's very unlikely that your database version will change between refresh intervals, it's entirely unnecessary to perform this additional database operation. You'll notice a definite decrease in the refresh performance if you have more than a few database servers to check and leave this one option turned on. Therefore, the recommendation is to keep it turned off at all times.