Polymorphic Table Functions (PTF) , Part 3 – Row Replication
In the third part of the PTF-series we learn how a PTF can change the cardinality of the input data flow: return more or less rows as in the input. We’ll use the same simple table as in the part 2 and our new task…
Online Statistics Gathering for ETL – Part 3
Preparing my session on Online Statistics Gathering for ETL for the DOAG conference, I noticed some points that I didn’t covered in the previous two blog posts. The first point is showing the problem that may arise if indexes are involved. The second one is…
Polymorphic Table Functions (PTF) , Part 2 – More Basics With Some Deep-Dive
In the first part of PTF series we went through a very basic example removing some columns and adding a new column with a constant value. Starting from the same example we’ll do something more meaningful in the second part. How about concatenating the values…
Polymorphic Table Functions (PTF) – Tinkering with Rowsets
Writing the second „basics“ post on PTF I discovered, that there were much more details worth mentioning, than it would be acceptable for a „basics“ post and would blow it up anyway 😉 So I decided to to separate the tests and finding in this…
Migrating from Windows to Linux with Active Duplicate for standby – problem with 11.2.0.4
Recently I was working on migrating Oracle 11.2.0.4 database running on Windows, to new hardware infrastructure on Linux. This Oracle version is with us for quite a long time, plus migration from Windows to Linux is quite common (fortunately in that direction…;)), so when I…
Star Schema Optimization in Autonomous Data Warehouse Cloud
Oracle Autonomous Data Warehouse Cloud does not allow to create indexes. Is this a problem for star schemas because no Star Transformation can be used? Or are the required bitmap indexes automatically created? A look under the hood of ADWC. A typical recommendation for star…
Polymorphic Table Functions (PTF) , Part 1 – Basics
I have already posted some examples on Polymorphic Table Functions in Oracle 18c in the last months. I quickly realized how difficult it is to explain completely new feature using advanced examples and wanted to write a series of posts starting from very basics. Now…
10 Tips to Improve ETL Performance – Revised for ADWC
The Autonomous Data Warehouse Cloud (ADWC) is a self-configuring, fast, secure and scalable platform for data warehouses. Does this mean we don’t have to take care anymore about performance of our ETL processes? Which performance tips are still important for us, and where can we…
Gathering Statistics in the Autonomous Data Warehouse Cloud
Optimizer statistics are essential for good execution plans and fast performance of the SQL queries. Of course, this is also the case in the Autonomous Data Warehouse Cloud. But the handling of gathering statistics is slightly different from what we know from other Oracle databases….
Bloom filters and parallel execution
Today I want to share with you another interesting example of solving performance problem which happened in the database used for Business Intelligence purposes. Users were complaining that the performance in kind of staging database (STGDB) was much better than the production one (PRDDB), even…
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