Database Reference
In-Depth Information
*.pga_aggregate_target=268435456
*.processes=600
*.remote_login_passwordfile='EXCLUSIVE'
*.resource_limit=TRUE
*.sga_target=268435456
*.undo_tablespace='UNDOTBS1'
As you can see, the double-underscore parameters in bold now include the
__sga_target
and
__pga_aggregate_target
settings as well as the various pools. These values are derived based on the last three
memory parameters shown in bold, as well as the observed server workload. In this fashion, Oracle will remember
your last optimal SGA/PGA settings and use them upon the next restart.
Summary
In this chapter, we took a look at the Oracle memory structures. We started at the process and session level, examining
the PGA and UGA and their relationship. We saw how the mode in which we connect to Oracle dictates how memory
is organized. A dedicated server connection implies more memory used in the server process than under a shared
server connection, but that use of a shared server connection implies there will be the need for a significantly larger
SGA. Then we discussed the main structures of the SGA itself. We discovered the differences between the shared pool
and the large pool, and looked at why we might want a large pool to “save” our shared pool. We covered the Java pool
and how it is used under various conditions, and we looked at the block buffer cache and how that can be subdivided
into smaller, more focused pools.
Now we are ready to move on to the physical processes that make up the rest of an Oracle instance.
