Oracle optimizer removing or coalescing subqueries
The Oracle optimizer often changes the query to get better performance. In this article, Jonathan Lewis explains two more optimizations involving subqueries.
2022-05-25
Oracle
Why your PL/SQL needs to be testable – and how to do it: Part 1
Part 1: What is testable code, why is it important, and first glimpses on practices that can help
2022-04-27
Oracle subquery caching and subquery pushing
In this article, Jonathan Lewis discusses why you might want to stop the optimizer from unnesting some subqueries and how to control where the optimizer positions each subquery.
2022-04-11
The effects of NULL with NOT IN on Oracle transformations
IN and NOT IN subqueries are frequently used in Oracle. Jonathan Lewis explains how the optimizer handles NULL with IN and NOT IN.
2022-03-18
Oracle ASM: Migrating from UDEV devices to the ASM Filter Driver
This article looks at the way in which you can convert unmanaged devices to the ASM filter drive in an Oracle system.
2022-03-04
844 reads
Running SQL Server on Oracle and Google Cloud
In this article, we will analyze the various out-of-the-box deployment options Oracle Cloud Infrastructure and Google Cloud Platform offers to host a Microsoft SQL Server database. This information can prove to be handy while deciding on the best cloud provider to host a given application or database.
2022-02-18
4,917 reads
Transformations by the Oracle Optimizer
To troubleshoot poorly performing SQL in Oracle, you must understand which transformations the optimizer has made. Jonathan Lewis demonstrates several possible optimizations for one query.
2022-02-09
Oracle sequences – 12c features including “identity”
Oracle added several enhancements to the sequence object in version 12c, including an “identity” column feature. Jonathan Lewis explains how to work with these new features.
2021-09-10
Typical uses of Oracle sequences
Oracle sequences supply unique numbers that can be used when populating tables. In this article, Jonathan Lewis explains the typical uses of Oracle sequences.
2021-08-04
Oracle Sequences: RAC
Using sequences when scaling up with Oracle RAC presents more issues with contention. In this article, Jonathan Lewis explains how to avoid the problems.
2021-05-31
Blogs
Registered for the Data Community Summit
By Steve Jones
I was reminded this week that I needed to get registered for the Data...
Daily Coping 5 Oct 2022
By Steve Jones
Today’s coping tip is to choose to see your mistakes as steps to help...
Restore HEADERONLY and FILELISTONLY
By gbargsley
Good day reader. This post is coming to you from a busy week in...
Forums
Change tracking - Date a row changed
We have change tracking enabled on one of our databases and I am looking...
Grant user permissions to a view but the base tables live in another database
I have two databases on the same server. I have a service account I...
The ORDER BY clause is invalid in views
Hi, I'm trying to run the below SQL code but I'm getting this error:...
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