Primary Author - Oracle Performance Tuning tirucamilo.ga database_erp//shtml. StorageXpert for Oracle – Visit us . Oracle Database Performance Tuning Guide, 10g Release 1 () . Introduction to Performance Tuning Features and Tools. Page Oracle Database 11g Release 2 () New Features in Oracle Database Performance .. xviii. Part I Performance Tuning. 1 Performance Tuning.
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Learn to optimize and fine-tune your Oracle system's overall performance. Implement tuning solutions using the proven methodology found inside "Oracle. there within the context of Oracle and performance tuning. So what is Oracle Performance tuning is rocket science and requires “expert knowledge” Oracle Performance Tuning book and various performance management papers on. Based on some experiences of many individuals, it is in fact that reading this Oracle Performance Tuning. By Gaja Krishna Vaidyanatha.
Q 9 What are the different types of backups that are available in Oracle? This can be achieved using either operating system utilities or RMAN. In contrast, logical backup allows taking backup of the database objects like tables, views, indexes, stored procedures etc.
Ans: Hot backup is the process of taking database backup while the database is in running mode. Hence, it is also known as Online Backup.
While cold backup can be taken only when the database is in shut down mode and hence it is known as Offline Backup as well. Hence, DBAs need to take the backup in online mode only. Q 11 What is the difference between restoring a database and recovering a database? Ans: During the restoration process, backup files are copied from the hard disk, media or tapes to the restoration location and later make the database operational.
Recovery has an additional step of updating these data files by applying redo logs so as to recover the changes which are not backed up.
Let me explain with the help of a scenario.
In order to do the same, redo logs can be applied which will bring the database to the point of failure. Q 12 What do you understand by Redo Log file mirroring? Ans: Redo log is the most crucial component of database architecture which records all of the transactions within the database even before it goes to the data file.
Hence, mirroring of these files will be done to protect them. Redo Log file mirroring allows redo logs to be copied to different disks simultaneously. And this can be achieved using Data Guard and other utilities. Q 13 How is incremental backup different from differential backup? Ans: Incremental Backup backs up only the changed data files since the last backup, which might be full or incremental.
The second incremental backup will only have the transactions occurred after Friday 10 AM.
While Differential Backup backs up the files that changed during the last full backup. Further, if the differential backup is taken on Sunday 10 AM, it will take the backup of the files changed since Friday 10 AM. If three tables are being joined, select the intersection tables as the driving table. The intersection table is the table that has many tables dependent on it. However, the WHERE clause should be written in the opposite order, with the driving tables conditions first and the final driven table last example below.
Depending on the number of rows and the presence of indexes, Oracle may now pick "D" as the driving table. This grouping of limiting factors will guide the optimizer more efficiently, making table "D" return relatively few rows, and so making it a more efficient driving table.
Choose the join order so as to join fewer rows to tables later in the join order.
The EXISTS function searches for the presence of a single row that meets the stated criteria, as opposed to the IN statement that looks for all occurrences. This estimation is prone to errors.
In case there is no way that the function can be avoided, use Functional Indexes. If a column is defined as a Varchar2 10 , and if there is an index built on that column, reference the column values within single quotes.
When you need to use SQL functions on filters or join predicates, do not use them on the columns on which you want to have an index, as in the following statement:.
Instead, use them on the opposite side of the predicate, as in the following statement:. Over a million developers have joined DZone. Let's be friends: Statspack is available with Oracle Release 8. Below are a few quick notes to help you get started. Please refer to the. It is suggested that you have your DBA set up Statspack to take a snapshot at regular intervals, and periodically generate a report.
Comparing snapshots taken during similar workloads can help pinpoint bottlenecks. Be sure to read the "When statistics and wait events can be misleading" section on page More support for: Sterling Selling and Fulfillment Suite.