Category: DATABASE

High CPU usage caused by the SCM0 background process in Oracle RAC

Published May 4, 2020 By Brijesh Gogia

The SCM0 background process in Oracle RAC (Real Application Clusters) is a component of the Oracle Clusterware and is responsible for managing the shared resources…

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SQL Profile and SQL Baseline in Oracle Database

Published April 21, 2020 By Brijesh Gogia

SQL Profile and SQL Baseline are both used to optimize the performance of SQL statements in Oracle databases. However, they work in slightly different ways:…

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PL/SQL lock timer wait event in Oracle Database

Published April 1, 2020 By Brijesh Gogia

PL/SQL lock timer wait event in Oracle occurs when a session is waiting for a lock held by another session to be released. This can…

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Oracle Multitenant DB 3 : Data Dictionary Architecture in CDB-PDB

Published March 20, 2020 By Brijesh Gogia

From the user and application perspective, the data dictionary in each container in a CDB is separate, as it would be in a non-CDB.

For example, the DBA_OBJECTS view in each PDB can show a different number of rows. This dictionary separation enables Oracle Database to manage the PDBs separately from each other and from the root.

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Oracle Multitenant DB 2 : Benefits of the Multitenant Architecture

Published March 19, 2020 By Brijesh Gogia

Oracle Multitenant database can provide few good benefits if we plan carefully and specially by having a non-traditional approach. In the starting it may seem intimidating to the seasoned DBAs as this architecture need some learning and practice. Few of the key benefits which Oracle describes are mentioned below:

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Oracle Multitenant DB 1 : Basics of Oracle Multitenant architecture

Published March 18, 2020 By Brijesh Gogia

The multitenant architecture enables an Oracle database to function as a multitenant container database (CDB).

This feature is available in Oracle Database 12c or later releases so you must install or upgrade to Oracle Database 12c or later releases. The database compatibility level must be set to 12.0.0 or later to utilize the multitenant feature.

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PGA parameters in Oracle database including hidden _pga_max_size

Published February 14, 2020 By Brijesh Gogia

A Program Global Area (PGA) is a memory region that contains data and control information for a server process. It is non-shared memory created by…

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Index Types in Oracle Database 19c

Published February 5, 2020 By Brijesh Gogia

Oracle 19c databases support several different types of indexes, each with its own specific use cases and characteristics. An index in an Oracle database is…

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Result Cache and “enq: RC – Result Cache: Contention” in Oracle Database

Published January 15, 2020 By Brijesh Gogia

The Result Cache is a feature in Oracle 11g and later versions that allow the database to store the results of frequently executed queries in…

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ORA-30036: unable to extend segment by 8 in undo tablespace

Published January 3, 2020 By Brijesh Gogia

The “ORA-30036: unable to extend segment by 8 in undo tablespace” error message in Oracle databases indicates that the undo tablespace has run out of…

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