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database provides us with options. The first that we will discuss is managing your data and the files in which they reside in a manual way. Another option, automatic storage management, is discussed in Chapter 9.
When you put the database in archive logging mode, the redo logs are written out to a directory that is named in your parameter or SPFILE. If that directory becomes full and the database attempts to write another archive log, the database activity will be suspended until sufficient space is made available for the new file. Create a large directory and schedule jobs to move the archive log files from online storage to tape before you encounter a space issue. RMAN does a nice job of helping you manage this. Please see Chapter 5 for more information on this.
Space should be managed at the datafile and tablespace level rather than at a lower level such as a table or index. Using locally managed tablespaces with uniform extent sizes will simplify your management. Do not worry that you have some extents in a tablespace or for an object. This does not create a performance issue since the extents contain a number of blocks that must be contiguous. You can see the amount of space available in your datafiles by selecting Datafiles in OEM, as in Figure 3-8. This shows the amount of free space available in the currently allocated space. If you have used the autoextend feature to allow a datafile to extend in size when more space is needed, the extra space is not shown in this graph. Do not allow temporary tablespaces or undo tablespaces to autoextend since they will grow to use all of the space.
TIP
Do not autoextend temporary and undo tablespaces, since they will quickly grow to use all of the space to which they can autoextend.
What do you do if you run out of space in a datafile? Just enter OEM, click the datafile, and choose the Storage tab. Once there, you can change the autoextend feature and enter the size of the extensions that you would like. Do not forget to limit the size of the datafile so that it does not grow to use all of your space. After you've completed this, click Apply and you're done. If you select the Show SQL button, you can see the alter database syntax, which is also shown next.
alter database datafile '/u01/oradata/ora10g/example01.dbf' autoextend on next 50M maxsize 5000M;
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