Oracle Database


This article is about functions and how to get more out of them if you combine them with record structures. Functions are the instrument in the Oracle Database to execute code and return a value. Nothing new here, everybody who develops in PL/SQL on the database knows that. In case you’re just starting with Oracle and want to know more about… Continue Reading →

All Things Oracle Full Articles, Database Development, Oracle Database, PL/SQL

In part 5 of this series I started working through a list of queries designed to demonstrate ways in which the optimizer can produce bad cardinality estimates. In this installment I’m going work through the remainder of the list. The outstanding queries are as follows: select count(*) from t1 where trunc_5 > ( select max(trunc_5) from t1 where mod_200 =… Continue Reading →

12c, All Things Oracle Full Articles, Performance Tuning

It’s been three months since I last published anything in this series on the Cost Based Optimizer, so a thumbnail sketch of the previous installments seems to be in order: In part 1 I gave an informal overview of how the optimizer would “think” about a simple query. In part 2 I created a data set, and ran a few… Continue Reading →

12c, All Things Oracle Full Articles, Performance Tuning

In Oracle Database Releases earlier than 12c, an Automatic Storage Management (ASM) instance runs on every node in the cluster, and ASM Cluster File System (ACFS) Service on a node connects to the local ASM instance running on the same host. If the ASM instance on a node were to fail, then the shared Disk Groups and hence ACFS file… Continue Reading →

12c, All Things Oracle Full Articles

Analytic functions have been part of Oracle for a very long time now – ever since 8i back in 1999. Analytic functions are an ANSI/ISO standard, and so you’ll find that they are similarly-implemented across a number of compliant databases. (This SQL Server article on “window functions” from sister site, Simple Talk, could very well have been talking about Oracle.) Analytic… Continue Reading →

All Things Oracle Full Articles, Database Development, Oracle Database

Introduction: Integrated Replicat is a feature unique to Oracle GoldenGate 12c, for Oracle Database versions starting from Oracle 11g ( and Oracle 12c (12.1.0). Classic Capture Mode: The Oracle GoldenGate Extract process captures data changes from the Oracle redo log files or archive log files on the source database system. Integrated Capture Mode: Oracle GoldenGate Extract process works directly with… Continue Reading →

12c, All Things Oracle Full Articles

Recovery Manager (RMAN) is the preferred tool to backup and recover the Oracle Database. You can use recovery catalog or the control file of the target database for RMAN Repository, but Recovery Catalog is the preferred method as it offers several advantages over the others, like reporting operations, simple recovery in case of control file damage, and more. Generally in… Continue Reading →

11g, 12c, All Things Oracle Full Articles

Introduction For versions of Oracle 11g R2, Oracle Recovery Manager (RMAN) replicates a database to a different Oracle home and opens it with NORESET LOGS option. From Oracle 12cR1, database RMAN introduced an option called ‘NO OPEN’, which duplicates your database to a new location and keeps it in an unopened state. Using this feature we can duplicate a database… Continue Reading →

12c, Backup and Recovery

Starting with Oracle Grid Infrastructure 12c (12.1), Oracle Cloud File system (ASM Cluster File System in cluster environment ) supports database files (database version and up) in addition to general purpose files so that entire Oracle databases can be stored inside Oracle Cloud FS and can leverage the Advanced Data Services such as snapshots, tagging and auditing although replication and… Continue Reading →

12c, All Things Oracle Full Articles

In the second installment of this series we looked at individual access paths for the tables in a simple join query to highlight an important flaw in the default model that the optimizer uses for indexes. Having taken advantage of a recent enhancement that addresses that flaw we are now ready to move onto the problems that appear with the… Continue Reading →

All Things Oracle Full Articles, Oracle Database