tailieunhanh - Oracle Database Administration for Microsoft SQL Server DBAs part 7

Oracle Database Administration for Microsoft SQL Server DBAs part 7 takes the administration topics with which the SQL Server DBA is familiar, translates them into Oracle terms, and then expands on Oracle functionality. Definitions and comparative terms run throughout the book so the SQL Server DBA can easily leverage existing knowledge. This Oracle Press guide also expands on some of the features in Oracle that do not match up directly with SQL Server, and looks at other processes often performed on an Oracle database that would not typically be a standard practice in SQL Server environments | 42 Oracle Database Administration for Microsoft SQL Server DBAs checkpoints run the database writers would join into the process to write the changed database blocks back to the datafiles. Understanding how Oracle handles transactions will help you in sizing the memory undo tablespaces and redo logs. Being able to have consistent reads in the database and provide a way to access the data without being blocked or needing to wait for transactions to complete is also key in the performance of queries against the database. Summary SQL Server has system databases such as master msdb model and tempdb. Even though Oracle does not have individual system databases that match the ones in SQL Server the platforms share some similar concepts. There is a need for system information there are parameters and options that can be configured and viewed and transaction logging keeps track of changes. Oracle has memory structures for supplying memory to server processes and user processes. There are individual parameters to manually configure memory or dynamic settings that are available in Oracle Database 11g by setting one parameter. Data dictionary views show the system information including the values of the parameters. Oracle offers quite a few parameters for tuning and adjusting to provide the best performance options. We went over only a small portion of them in this chapter but you have a starting point for common requirements. Temporary and undo tablespaces are distinctive features of Oracle. It is able to have more than one temporary area that can be assigned to different users to isolate their sorting and temporary table processing. The undo tablespace keeps track of the before and after copies to provide consistent reads for concurrent users and be able to roll back changes if needed. Changes are written to redo logs and kept in the undo segments to handle transactions. There is also a memory cache for the logs to buffer the log for the log writer to be able to process the