If cold backups are a norm at your workplace, then this is a sign of a dinosaur. Little to no downtime applies to production instances, but non-production should be mostly up during working hours with only intermittent outages. Each organization has its own Outage Handling Procedures —depending on whether it is planned or unplanned downtime. Most DBAs are assigned a database to be the primary contact when there is an outage issue on call.

Outage handling usually includes something similar to the following:. Initial troubleshooting to determine the type of outage : Evaluate any automatic failover procedures to check for success. Forecasting the amount of time before resolution : This is the point for making the decision if a manual fail over is needed.

Bringing the application or database back online : Not all failures are due to the database being down, even when that is what first appears to be the case. Root cause analysis : What was the real reason for the outage? This is not always evident at first glance. Future preventive actions : Evaluating and rewriting the outage procedures, reassigning team members for outage coverage. Outage handling is an important process and includes quite a few non-DBA team members who must coordinate efforts, and not just point fingers to get this issue resolved.

These types of procedures should be well documented in both print and online form for disasters with a definite line of authority as to who can execute the procedures with administrative approval. Speaking of the human side of things, the following list details how to avoid the really bad things that can happen to even experienced DBAs. Remember if you are a novice or new DBA, you shouldn't have access to certain servers or databases because your superior understands how easy it is to do the wrong thing at the wrong time.

The following list may seem harsh, full of should and don't statements, but I felt it was important to state exactly what others have experienced or witnessed personally. Think of it as an experienced DBA giving someone under them some good advice about what to avoid. It would be even better if you renamed the entire directory and left it in place renamed for a day or two.

Assuming that all of the datafiles in a certain directory only pertain to one database is a recipe for disaster, those files can be created anywhere on the filesystem as long as Oracle has write access. It is best to use the Unix utility called fuser against a database file before using an rm or mv command because it checks if the file is actively being used. Another way would be to force a database checkpoint and check the timestamp before removing.

If it is an active datafile, the timestamp would be current. This will prevent many a disaster by visually checking the prompt before running a script in what you think is a non-production database. Instructions on how to do this come later in the book. This will add more visual clues to ensure that you know exactly what you are modifying. Copy and paste into a text file and run it instead.

Type the word production into the command-line window after you finish using it. This will prevent disasters if you accidentally switch windows and run something you shouldn't have. It will only produce an error because there is no command called production. It is best to run recovery scenarios on a different server from any running production. Also, test operating system restores. Disaster recovery sites should also be located on a different server for true failover capabilities.

Make sure you know how to use the command line for all of the Oracle utilities and Unix vi editor just in case you have nothing else at your disposal. It is suggested to make your production windows, application, or command-line utility like PuTTY a completely different color for production versus non-production, and the scrolling history as large as possible.

Unix has a history capture utility called script. Tell someone else you are modifying something… just in case. Saying it aloud may give someone else time to stop you or at least give you a mental check on what you are doing.

Log rotating scripts can play havoc with naming the online redo logs with a file extension of log. Using the letters rdo would be safer.

Unknown outside consultants won't necessarily give the best advice. Be wary until you are sure of their expertise and ability. If at all possible, ask to do the work under their guidance so that you know what is actually occurring. Double check by tracking the operating system's performance on a server, especially running out of file space. Beware the reuse clause when adding or altering a database file. This command can overwrite an existing datafile, which destroys any existing data.

Be wary of scripts generated by third-party tools, they can be too powerful. A script to recreate an object usually drops it in the first line. This can be disastrous if the data has not been saved. Be sure to investigate the addition of resource limits for any users that have ad hoc SQL access in production.

Make sure the system administrators know not to modify, move, or delete anything that belongs to the Oracle accounts. The Unix root account is not intended for everyday use and especially not suited for Oracle tasks. Investigate the use of sudo for tracking root-authorized activities. This is the most important blunder-avoiding tip—it is wisest not to do anything that you can't undo, reverse, or fix. As a new DBA, one of the hardest things to figure out is the philosophy behind the position.

The best DBAs in the business seem to have an underlying sense or gut feeling when something is wrong, and when to speak up and say no. This feature provides a robust connection pool for Java applications with improved throughput and fast failover in an Oracle Real Application Clusters environment.

UCP for JDBC provides advanced connection pooling functions, improved performance, and better diagnosability of connection issues.

The following sections describe new database features for Oracle Database 11 g Release 2 The following sections provide new feature information for Flashback Data Archive and instance caging. Oracle Database 11 g Release 2 This includes:. The Associate procedure enforces schema integrity after association; the base table and history table schemas must be the same. This feature makes it much easier to use the Total Recall option with complex applications that require the ability to modify the schema.

With Instance Caging, users can partition CPU resources among multiple instances running on a server to ensure predictable performance. This feature improves efficiency by enabling users to be notified of any job activity that is of interest to them without having to constantly monitor the job. This feature improves efficiency and ease-of-use. Jobs with file dependencies are automatically triggered when the specified file is received instead of constantly monitoring for the file.

This is a key feature for Enterprise Manager scheduling. It improves efficiency and ease-of-use by enabling a job to be run on multiple nodes while managing it as one entity from a central location. It improves efficiency and ease-of-use by enabling job scheduling in a distributed environment to be managed centrally. The following features provide improvements to the various utilities in Oracle Database 11 g Release 2 Data Pump Legacy Mode provides backward compatibility for scripts and parameter files used for original Export and Import scripts.

Development time is reduced as new scripts do not have to be created. This allows Java applications running in the database to connect to and accept connections from both IPv4 and IPv6 hosts. Oracle Database Java Developer's Guide for details. The following sections describe diagnosability features for Oracle Database 11 g Release 2 Enterprise Manager Support Workbench is a GUI workbench for customers and support to ease diagnosis and resolution of database errors.

This feature extends the benefit of Enterprise Manager Support Workbench to ASM by helping customers package all necessary diagnostic data for incidents. The following sections describe new information integration features for Oracle Database 11 g Release 2 XStream provides application programming interfaces APIs that enable client applications to receive data changes from an Oracle database and to send data changes to an Oracle database.

These data changes can be shared between Oracle databases and other systems. The client application is designed by the user for specific purposes and use cases. Oracle Database XStream Guide for details. The following sections describe improvements in performance of the database and functionality of performance-related database features. New in Oracle Database 11 g Release 2 By providing a migration path, old applications using stored outlines can be transparently migrated and can instantaneously take advantage of the enhanced functionality of SPM.

Oracle Database Performance Tuning Guide for details. Table annotations support provides the ability to annotate a table as being cache worthy, which enables applications to leverage client and server result caching through deployment time knobs as opposed to making application changes.

In addition, this feature provides automatic client cache invalidation. This feature allows non-intrusive application performance acceleration using client and server result caches. Today, disk drives have byte sectors. Disk drive manufacturers are moving to 4 KB sector drives because it allows them to offer higher capacity with lower overhead. If customers use 4 KB sector drives as byte sector drives, then there is likely to be a performance penalty because they have to run in byte emulation mode.

This feature allows Oracle to work with 4 KB and byte sector drives without a performance penalty. This feature allows customers to take full advantage of new generation, higher capacity disk drives.

The new features discussed in the following section cover areas that include encryption and auditing. Significant new encryption key management functionality has been introduced in Oracle Database 11 g Release 2 to enable complete integration with Hardware Security Modules and increased performance for Transparent Data Encryption. Audit Management has been simplified through the introduction of a new package for managing audit data on the Oracle database.

Automating the periodic deletion of audit records from the database tables and operating system files after they have been securely backed up or are no longer needed. Controlling the size and age of the audit trail written to operating system files before a new operating system audit trail file is created. Audit Trail Cleanup reduces the time and cost required to manage the Oracle database audit content. It enables you to dedicate an optimized tablespace for audit records and move the audit tables out of the SYSTEM tablespace for improved performance.

In addition, it provides automated deletion of audit records from the database tables and operating system files. Encryption key management provides the ability to change the master key associated with transparent data encryption TDE encrypted tablespaces.

The tablespace master key is used to encrypt the encryption keys associated with individual tablespaces. This is commonly referred to as a 2-tier key architecture.

Prior to Oracle Database 11 g Release 2 In Oracle Database 11 g Release 2 This support is now available in this release. Oracle Database Advanced Security Guide for details. The following sections describe server manageability features for Oracle Database 11 g Release 2 These features extend the capabilities of Automatic Storage Management ASM to support all types of data including database files, clusterware files, and file system data such as Oracle homes and binaries.

ACFS provides support for files such as Oracle binaries, report files, trace files, alert logs, and other application data files. ACFS supports large files with bit file and file system data structure sizes leading to exabyte-capable file and file system capacities.

ACFS scales to hundreds of nodes and uses extent-based storage allocation for improved performance. A log-based metadata transaction engine is used for file system integrity and fast recovery. The ACFS on-disk structure supports endian neutral metadata. This eliminates the need for expensive third-party cluster file system solutions while streamlining, automating and simplifying all file type management in a single node as well as Oracle RAC and Oracle Grid infrastructure for a cluster computing environments.

ACFS supports dynamic file system expansion and contraction without any downtime. Oracle database files as well as non-Oracle database files, for example Oracle binaries, can now reside on ACFS eliminating the need for third-party file systems or volume managers to host general purpose files. They may reside in existing ASM FS storage or in an additional storage device and persist following a system restart.

Even as the file system changes, the snapshot does not, giving you the ability to view the file system as it was at the time the snapshot was created. Initially, snapshots are read-only, which preserves their point-in-time capture. The original file system can continue to change but the static nature of the snapshot makes them ideal as a source for backup without keeping the original file system offline.

ASM FS Snapshots can be used as a source for data mining or report applications which need to work on a static, point-in-time data set. Consequently, the OCR tolerates loss of the same number of disks as the underlying disk group. OCR is relocated in response to disk failures.

Should the disk holding the voting disk fail, ASM selects another disk to store this data. Disk drives have higher transfer rates and bytes per track on the outer tracks. This makes it preferable to keep the hotter data closer to the edge of the disk; that is, the lower numbered blocks. This feature enables ASM to identify higher performance disk regions. This release now allows the configuration, monitoring, and management of Optimal Disk Placement with Enterprise Manager which is the graphical user interface GUI for management.

Automatic Storage Management ASM on UNIX platforms implements access control on its files to isolate different database instances from each other and prevent unauthorized access. The new security model and syntax is coherent with those already implemented for the objects represented in Oracle Database. Multiple database instances can store ASM files in the same disk group and, therefore, are able to consolidate multiple databases with security.

This prevents unauthorized database instances from accessing or overwriting each other's files. Enterprise Manager provides a graphical user interface which makes is easier to manage the environment whether it is a standalone server or a cluster deployment of ASM. The centralized console provides a consistent interface for managing volumes, database files, and file systems as well as the Oracle Database.

The following sections describe general database management features to ease database management. Enterprise Manager Configuration Assistant EMCA has been updated to support the new configuration required for Enterprise Manager to support new features of the release. Configuration assistants automate the configuration of the environment ensuring the correct steps are taken. The assistants simplify the configuration of Enterprise Manager in clusters and clustered database settings.

Time stamp with time zone data could become stale in the database tables when the time zone version file is updated. Today, users have to manually fix the affected data. This feature updates the system and user data transparently with minimal downtime and provides automatic and transparent patching of time stamp with time zone data whenever a time zone file is updated. Also, when a server time zone version is patched, all of the clients that communicate with the server need to be patched as well.

This new feature provides automatic and transparent patching of time stamp with time zone data whenever a time zone file is updated. Oracle Database Globalization Support Guide for details. The initial segment creation for nonpartitioned tables and indexes can be delayed until data is first inserted into an object. Several prepackaged applications are delivered with large schemas containing many tables and indexes. Depending on the module usage, only a subset of these objects are really being used.

With delayed segment creation, empty database objects do not consume any space, reducing the installation footprint and speeding up the installation. Unusable indexes and index partitions no longer consume space in the database because they become segmentless. Unusable indexes and index segments are not usable for any data access. Any space allocated by this unusable dead object is freed as soon as an object is marked unusable.

The Metadata API has been enhanced to provide a cross database comparison tool to compare object metadata of the same type from different databases. Full XML is typically complex and opaque. This feature enables users to compare objects between databases to identify drift that is, metadata changes over time in objects of the same type. A Replay Compare Period Report performs a high-level comparison of workload replay to its capture or to another replay of the same capture.

The Replay Compare Period report contains a summary of the most important changes between the two runs in terms of performance, errors and data divergence. This makes it easier for Database Replay users to understand and test the impact of system changes. Replay Compare Period Report simplifies understanding and assessment of the impact of system change in testing by providing summarized information on how the replay performed versus capture or other replays in terms of performance, errors and divergence.

Oracle Database Testing Guide for details. Comparison of two such trials built from two different STSs. A detailed comparison report including any new or missing SQL statements in one and not in another trial and any plan changes noticed in the compared trials is compiled.

The two STSs are captured as follows:. Compare STS feature can also be used in non-Database Replay scenarios where customers already have existing test scripts and can capture the SQL into two STSs; one for before system change and one for after.

Having ASH data available on standby systems for Data Guard environments allows customers to troubleshoot performance problems specific to their standby environments.

Oracle Database High Availability Overview for details. Article Contributed By :. Easy Normal Medium Hard Expert. Writing code in comment? Please use ide. Load Comments. What's New. Most popular in How To. How to Recover a Deleted File in Linux? Most visited in Installation Guide. Installation of Node. Automatic Memory Management in Oracle Database 11g Release 1 - Oracle 11g takes the next step down the road to making manual memory management a thing of the past.

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Database Replay in Oracle Database 11g Release 1 - Capture workloads on a production system and replay them exactly as they happened on a test system. Database Resident Connection Pool DRCP in Oracle Database 11g Release 1 - Use the database resident connection pool to reduce the resource requirements of applications that do not support connection pooling.

Data Recovery Advisor in Oracle Database 11g Release 1 - Automatically identify, diagnose and repair corruption or loss of persistent data on disk using this new feature. Finer Grained Dependency Management in Oracle Database 11g Release 1 - See how finer grained dependency management in 11g reduces the extent of invalidations associated with schema changes.