Step by Step Upgrading Oracle 10g to Oracle 11g

Recently we did database upgrade from 10g to Oracle 11g.I would like share that activity with you. Pre-Requisite: You should have the Oracle database 10g, which you want to migerate. Also here we are upgrading to Oracle Database 11g – Beta 6 (11.1.0.6) Step 1) Installing Oracle 11g Home We cannot upgrade the existing Oracle [...]

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Oracle 9i Architecture

Introduction This is the basic architecture of Oracle 9i . This is the basic concept about Oracle and this is the backbone of Oracle DB. I that this would be the first which related to Oracle. An Oracle database is a combination of oracle Instance and data files on the file system. Oracle Database = [...]

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How to adjust the high watermark in ORACLE 10g – ALTER TABLE SHRINK

Yesterday my junior team member was confused about fragmentation and High water mark concepts.Also there was good comment on my fragmentation post, so it inspire me to write something about the High Watermark and the Oracle 10gR1 New Feature SEGMENT SHRINKING.About fragmentation I have already disscused in my previous post. The High Watermark is the [...]

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Oracle Backup and Recovery Solutions

When implementing a backup and recovery strategy, you have the following solutions available: – Recovery Manager (RMAN) This tool integrates with sessions running on an Oracle database to perform a range of backup and recovery activities, including maintaining an RMAN repository of historical data about backups. You can access RMAN through the command line or [...]

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What and when Index Scans is used

In case of index scan a row is retrieved by traversing the index, using the indexed column values specified by the statement. An index scan retrieves data from an index based on the value of one or more columns in the index. To perform an index scan, Oracle searches the index for the indexed column [...]

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Index Skip, Full, Fast Full Index, Index Joins Bitmap Indexes Scan

A)Index Skip Scan —————————————- As the name suggest index skip scan does not scan complete index. But it scan of the subindexes. Index skip scan lets a composite index be split logically into smaller subindexes. In skip scanning, the initial column of the composite index is not specified in the query. In other words, it [...]

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Sample Table Scans in Oracle

•A sample table scan retrieves a random sample of data from a simple table or a complex SELECT statement, such as a statement involving joins and views. •This access path is used when a statement’s FROM clause includes the SAMPLE clause or the SAMPLE BLOCK clause. •To perform a sample table scan when sampling by [...]

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When you would make Index and when not

* Create an index if you frequently want to retrieve less than 15% of the rows in a large table. * To improve performance on joins of multiple tables, index columns used for joins. * Small tables do not require indexes. Some columns are strong candidates for indexing. Columns with one or more of the [...]

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