Submitted by saibal on Thu, 2007-05-10 02:05
Oracle 10g’s brilliant alternative to database point in time recovery is the the Flashback Database feature. With this feature in place you can do almost everything that you can with point in time recovery, without actually having to go through all the disruptions and hassle that a PITR necessarily entails.I recently had a first hand opportunity to see the power of this feature, when I ran a scriptfile to drop tables and unwittingly dropped one of the tables containing sensitive information belonging to my employer Creative Infotech. I later recovered the table and was amazed at seeing how easy it had become to get back dropped objects in Oracle 10g, especially Release 2. Below is a simplified version of what I did
Submitted by saibal on Sat, 2007-04-21 00:27
Advanced features of Oracle Net include failover and load balancing. These features are actually interrelated in as much as you usually don’t have one without the other. While they are mostly used in a RAC environment, they can be set up in a single instance environment as well.
In the context of Oracle Net, failover refers to the mechanism of switching over to an alternate resource when connection to the primary resource gets terminated due to any reason. Connection failure may be broadly categorized as:
Submitted by KrishnaBoppana on Mon, 2007-04-16 14:35
“Find out how to use DBMS_SQLTUNE package to tune SQL Statements in Oracle 10g”
Have you ever been frustrated with SQL Tuning?
Did you get lost in the maze of /+ HINTS +/ and analysis paralysis?
Pre-10g you have to be either a SQL tuning expert or should have a license to expensive tuning tools available in the market to effectively tune SQL Statements. Not the case anymore.
In 10g you can use DBMS_SQLTUNE package to get tuning recommendations for SQL Statements.
Tuning of SQL Statements using DBMS_SQLTUNE involves following 4 steps:
Submitted by golak.sarangi on Sun, 2007-04-15 04:46
Every PL/SQl devloper must have tried their hands with dynamic SQl. Its an indelible part of oracle.But its generally used when we dont know at compile time about the object on which we are to perform the task. Suppose we want to insert data into a table but we get the name of the table during the execution of the procedure, in those cases we would use dynamic SQl with the table name passed as bind variable. Dynamic Sql is even used to execute DDl commands inside a PL/SQl block.
Submitted by Kevin Meade on Mon, 2007-04-09 17:07
Been doing a lot with Historical Perspective lately. This has caused me to think a bit about the different variations of lookup that can be called a Point In Time query. My customers have found this discussion useful in understanding the details of how their report programs find specific rows in time. It is helpful to them because it provides an understanding as to why a specific row shows up on a report, and thus allows them to create more exacting definitions of what they want. Plus I find it is a good primer for newbies on staff to read so they don't make the same mistakes we made when we first started doing PIT queries. Maybe you can use it too.
Submitted by abatishchev on Fri, 2007-04-06 08:54
Once upon a time Le Petit Chaperon Rouge (LPCR) decided to change db_files from 200 to 300 on a busy cluster of four nodes.
Soon after the change applications started to block each other, timeout and crash (enq: TX - contention, cursor: pin S wait on X, enq: HW - contention). Those applications which were actively inserting into LOB columns - suffered the most.
Many lock holders were waiting for "DFS lock handle". Thus LPCR learned that DFS stands for "Distributed File System".
As soon as she reversed the changes - everything went back to normal.
Submitted by Kevin Meade on Wed, 2007-03-28 17:15
One of my recent clients had a real data twisting process to validate. It didn't help much that their source had been corrected by many "ONE-SHOTS" over the years to deal with bugs, and accounting methods mandated by Act of Congress. What we needed was a way to see changes in a stream of related rows. In the end I created for them, a solution that allowed developers to pick two rows from a table at random and compare them in SQL with a result set returned showing only differences. Its a simple thing, but kind of neat, and very useful. So I'd like to share it with you.
Submitted by Kevin Meade on Mon, 2007-03-26 17:24
Recently my friends at work saw me doing things with indexes they didn't understand. They saw what looked like unneeded columns in some indexes, and funny expressions they didn't know could be done in an index. So I explained to them the benefits of INDEX ONLY ACCESS, and FUNCTION BASED INDEXES. They had not seen these two techniques before so I figured maybe other people would be interested too. Here is it, a short discussion on what are fast becoming my two favorite tuning techniques.
Submitted by saibal on Sun, 2007-03-25 11:35
To continue with the shared server series, as mentioned in my last post, I will here be taking up the issues of configuration of memory, and the management of shared servers using available data dictionary views and initialization parameters.
How much memory should you configure for shared servers?
Submitted by saibal on Sun, 2007-03-25 11:33
So, to continue with our shared server series, let's begin with how a user connects through a shared server connection: