When you develop an application that uses a database, one of the topics you need to consider is how to connect to the database. Some application use a one-to-one connection,
Tag: performance
High CPU With Queries Without Bind VariablesHigh CPU With Queries Without Bind Variables
Performance problems can be tricky, and everyone has a different method to approach them depending on the exact issue. In this case I’d like to cover a specific case of
Did You Know #35 – New Child Cursor Creation ReasonDid You Know #35 – New Child Cursor Creation Reason
In many cases we see a new child cursor for existing SQL. You can see the children and their information in V$SQL (where CHILD_NUMBER identifies the child). To see the
Strange Index BehaviorStrange Index Behavior
During a performance problem I had with a query I wanted to create an index on the table. Since this was a large table I wanted the index to include
Top-N QueriesTop-N Queries
This is an old story. It started in 2015 when I found a problem with TOP-N query performance. I wrote a blog post about it and later an update. Here
External HDD PerformanceExternal HDD Performance
This is not a technical post and it’s not related to the database world. It’s just a short experience I had with external HDDs as a simple user so I
Order of Predicate Execution #2Order of Predicate Execution #2
In the previous post I talked about the order of predicate execution based on the predicate position and inline view.As promised, in this post I’ll add statistics and see what
Order of Predicate Execution #1Order of Predicate Execution #1
In my previous post, I wrote about the parsing operation and what happens first. In the footnote I said that the order doesn’t affect performance, the cost based optimizer doesn’t
Did You Know #21 – Adaptive FeaturesDid You Know #21 – Adaptive Features
When Oracle are adding a new feature to the database, they usually add a parameter to control it. Sometimes, after adding feature and the parameter, they realize that the parameter
Reading AWR Report – Part 3Reading AWR Report – Part 3
After talking a bit about the AWR report (if you haven’t read the previous posts, you can find part 1 here and part 2 here), I think one of the