11g

Data Guard Physical Standby Database Best Practices – Part II

Wissem El Khlifi on 27 September 2012 with 14 comments

Read Data Guard Physical Standby Database Best Practices – Part I In this second part we will setup the standby database and enable Fast Start Fail Over. Standby Database Creation Start the standby database instance in NOMOUNT start up mode: SQL> startup nomount pfile=initdg2.ora; Now that the configuration of the standby server is complete, let’s perform the duplication from the… Continue Reading →

Convert Single Instance to RAC – Part 1: Duplicate DB using RMAN

Satishbabu Gunukula on 20 September 2012 with 20 comments

This article is for users of Oracle Database version 10g+ who want to convert their Oracle single instance database to RAC.  I will provide detailed procedure for converting non-RAC database to RAC and we will use Oracle Automatic storage management (ASM) as shared storage. In general, if the database is small then you can consider installing a new RAC database… Continue Reading →

Migrating a 2TB database to a new operating system with different endianness

Steve Harville on 19 September 2012 with 2 comments

I recently moved a 2TB database from Linux, Oracle 11.1 to AIX, Oracle 11.2 using impdp with network_link and parallel options. The data was imported in about two hours and the indexes took another 7 hours. There was no downtime but we kept the users off the system while this was happening. Here is the command I used on the… Continue Reading →

Data Guard Physical Standby Database Best Practices – Part I

Wissem El Khlifi on 07 August 2012 with 20 comments

Introduction Oracle Data Guard is one of the software solutions provided by Oracle Corporation to maximize high availability of Oracle databases. Oracle Data Guard maintains one or many secondary databases as alternatives to the primary production database. Data Guard Architecture Oracle Data Guard supports both physical standby and logical standby sites. Physical Standby: When the primary database transactions generate redo… Continue Reading →

Incremental Partition Statistics Review

Randolf Geist on 01 August 2012 with 0 comments

Here is a summary of the findings while evaluating Incremental Partition Statistics that have been introduced in Oracle 11g. The most important point to understand is that Incremental Partition Statistics are not “cost-free”, so anyone who is telling you that you can gather statistics on the lowest level (partition or sub-partition in case of composite partitioning) without any noticeable overhead… Continue Reading →

Dynamic Sampling (III) – Real-Life Data – Part II

Randolf Geist on 05 July 2012 with 0 comments

In the previous installment of this series we saw that Dynamic Sampling wasn’t of great help when dealing with certain types of data patterns. We tried to add a suitable index to improve the Dynamic Sampling results, but no luck so far. The solution in this case is that with statistics in place the index only gets used when adding… Continue Reading →

Dynamic Sampling (III) – Real-Life Data – Part I

Randolf Geist on 20 June 2012 with 2 comments

In the previous parts of the series I outlined the basics on Dynamic Sampling. Let’s see how Dynamic Sampling deals with typical real-life data patterns. As you might be aware, quite often real data follows certain patterns for how data is clustered together, usually related to how the data arrives. This clustering (or scattering) of data within a table can… Continue Reading →

Nested Loop Join Costing

Randolf Geist on 14 June 2012 with 0 comments

The basic formula for calculating the costs of a Nested Loop Join is pretty straightforward and has been described and published several times. In principle it is the cost of acquiring the driving row source plus the cost of acquiring the inner row source of the Nested Loop as many times as the driving row source dictates via the cardinality… Continue Reading →

Introduction to Oracle Flashback Technology (Part 3: Flashback Database)

David Njoku on 12 June 2012 with 1 comments

In this series of articles, we are discussing the collection of tools that make up the Oracle Flashback Technology suite. They are varied in their purpose and in their implementation, but together they act very much like a morning-after pill for your database, a means by which developers and administrators can protect their database from immediate past errors and indiscretions…. Continue Reading →

Training a new DBA on investigating performance problems

Steve Harville on 30 May 2012 with 5 comments

We have a new DBA in training and part of my job is to mentor and demonstrate good Oracle practices. Here’s a write up I made for him on how I solved a performance issue. Issue: The BI team complained about a large query in out production BI database that had been running slowly for the past few days. Steps to resolve: Action… Continue Reading →