Pdf oracle dba handbook

Almost all activities against the database are tracked in the online redo logs. As transaction are initiated and eventually committed or rolled back, a record of this activity is written to these log files. Log writer writes to redo logs sequentially. A checkpoint is an event that flushes modified data from buffer cache to disk and updates control file and data files. Checkpoint occurs automatically when an online redo log file fills log switch.

There is also an assortment of other cleanup activities that may need to be done, which are SMON's responsibility. The SMON process by itself checks every so often to see whether there are any tasks waiting for its attention. Manageability monitor MMON From 10g, it makes snapshots of the database's health statistics and stores this information in the automatic workload repository. In Vista, you need to run these batch files as administrator.

Please note that Server Manager tool is no longer available from Oracle 9i onwards. You can do everything using SQL Plus! For various day-to-day database works, you may find SQL Plus cumbersome to work with. For this, several 3 rd party GUI tools are available.

Redo log filesRedo entries record data changes that can be used to reconstruct all changes made to database. To operate successfully, an Oracle instance requires at least 2 redo log groups. Each group must have at least 1 redo log file. Usually in production databases, there are at least 3 redo log groups and each group has at least 2 redo log members. Note that, all member files under same group are identical. Members are multiple copies to protect against data loss in case of disk failure.

IfLGWR can write to at least 1 member of the group, database functions normally, but otherwise Oracle shuts down the instance. Blocks are smallest logical unit of storage in Oracle database. An extent is logical storage unit made of contiguous data blocks. Segment is logical storage unit made up of one or more extents. Types of segments are -table, table partition, cluster, nested table, index, index organized table, index partition, temporary, LOB, undo, bootstrap.

Undo segmentWhen a user performs an update or deletes operation, the earlier data is saved to undo segments and then actual data is modified to new value. In case of insert operation, rowid of new rows are stored in undo segments. Undo data is not deleted immediately after commit or rollback. When a transaction is rolled back, Oracle restores the earlier data from undo segments. From Oracle 9i, undo management can be automatically controlled.

To use automatic undo management, set following parameters in initialization file. Object privilege -provides permission to access schema objects. Granted for specific objects.

RolesA role is named set of privileges. Backup and Recovery IntroductionWhen instances crashes for any reason e. Power failure Oracle automatically recovers when database starts next time. The most important decision you need to take for backup is to decide whether the database will run in archive or no archive log mode.

Usually production databases always run in archive log mode. Ideally, each member of archive log groups should reside in different physical disks so that if one disk gets corrupt, identical copies can be retrieved from another disk. If you use RMAN, you can have incremental backups i. RMAN is not discussed in this book. Backup and recovery in no archive log modeWhen the database is running in no archive log mode, only cold back up can be taken.

The steps are Shutdown the database 2. Copy data files, control files, redo log files using OS commands to a backup location. If relocation of files is necessary, you need to open the database in mount stage and issue rename command to specify new location of the files. Then you should open database for normal use. In no archive log mode, you can only recover data, which was taken during back up period. Even if only one file is corrupt, you need to restore all files and recover entire database.

Backup in archive log modeIn archive log mode, backup can be taken while database is running. To take backup of data file, follow these steps Use OS commands to copy data file 3. Ideally, perform hot backup when there is less DML is occurring in the database. User managed complete recoveryIn all the following cases, it is assumed that database is running in archive log mode and backup was already taken. This section highlights the concepts and a general overview of the players that deliver this proprietary database management system.

These oracle dba tutorial players fall into three main categories:. System support infrastructure a mix of background and foreground processes that perform the tasks required to facilitate the application interaction with the 12c database. Operating system files a suite of no less than ten files that play individual roles as the database runs.

This course will help you to achieve excellence in this domain. Shared memory is nothing more than a newfangled name for what was and is sometimes still referred to as RAM—random access memory.

As the 12c database is started, a handful of entries in its system parameter file contribute to the size of memory allocated to the instance. In a recent forum discussion I wrote down a rough outline of the approach I think people should take to become a competent DBA.

This article represents my thoughts on that matter. Remember, this is only an opinion. When you are new to Oracle, you want to minimize the number of unknowns you throw into the mix.

As such, you should probably start the learning process on the operating system you are most familiar with. If you are happiest on Windows, then by all means try the Windows downloads of Oracle Database. It's a good way to get into the product, without having to start learning any new OS technology. Maintain a high-performance Oracle Database using the best practices and expert techniques in this Oracle Press guide. Oracle Database 12c DBA Handbook is thoroughly updated to cover the new features and utilities, including the multitenant architecture, Oracle Database In-Memory option, and cloud enhancements.

Real-world examples for every major configuration are included. This site comply with DMCA digital copyright. We do not store files not owned by us, or without the permission of the owner. We also do not have links that lead to sites DMCA copyright infringement. If You feel that this book is belong to you and you want to unpublish it, Please Contact us.