Mostly data; on Oracle, Kafka, Python, and whatever I find interesting.

I needed a place where I can publish solutions to problems I’ve met in different areas without worrying about much else.

Docker for Mac - Increase Swap

Building Docker image with Oracle XE

In an attempt to compare how long it will take to build a Docker image of Oracle XE (11.2) vs EE (12.2) on my Mac I ran into a problem. The building of XE failed, it complained that only 1023 MB swap space was available. I thought that adding swap during build with this workaround would do, but it turns out that with Docker things are different. I found suggestions here, but since I was not reading carefully enough, I missed the point that you add swap to the hypervisor Docker for Mac is running on. [Read More]

Slow SQL From Monitoring Software

Queries from monitoring software like BMC are not supposed to be among Top SQL, but that was happening in many databases at one site. This may happen if the dictionary statistics are not updated, leading Oracle to choose the wrong plan. Document with ID 1328789.1 on MOS shows an example of this. So the SQL that came from BMC sometimes took up to a minute and was executed every 5 minutes, easily making it to the Top SQL list in Enterprise Manager / Cloud Control. [Read More]

Flashback Tables

Help your developers to run more tests

It is probably the developers’ responsibility to run tests, but they may not be aware of features in the database that makes the testing easier. Here the other day an ETL developer asked for help with resetting tables after ETL-testing. But there was no need to create complicated scripts to do so. I showed him flashback tables so he could easily fix it himself and run the tests over and over again without any pain. [Read More]

Invisible Tables

A colleague said that he had some tables that showed up in one tool, but not in another, I think it was Enterprise Manager/Cloud Control. This is easy to forget if you don’t work with non-relational tables regularly. What happens is that only relational tables are listed in DBA_TABLES or USER_TABLES, but all tables can be found if you search DBA_OBJECTS / USER_OBJECTS for objects with OBJECT_TYPE=TABLE. The documentation actually says: USER_TABLES describes the relational tables owned by the current user. [Read More]

You should speak at UKOUG Tech17

Statistically there has to be someone like you, who wants to know about your experience

Have you been in a presentation with the feeling that the speaker is talking over your head? As if he is speaking to a select group, maybe trying to impress them? The selection of words and expressions, subject for the talk may sometimes give a feeling of cleverness, yet you can’t relate to it. Instead you walk away thinking you are not remotely smart enough to give a presentation. That is too bad. [Read More]

Normalizing Data Sets

Importing one-file datasets to your relational database

Here the other day I was helping my son with his homework. His task was to create a simple data model, create it in MySQL, and make a simple web page to access the data. I thought that after creating a few INSERT statements on his own I could help him with demo data. Since he had decided to create a movie database I googled for some movie data sets and decided to use the IMDB 5000. [Read More]

Hi there!

I just got started. With a new blogging platform. I was frustrated with the way things went and wanted to start over with something else, something simple and not pretentious at all. Something that let me spend time on writing the post, and not on formatting the code when I had some SQL to show. Just plain and simple. My previous blog used to be mostly about Oracle, but I spend more and more time looking into Hadoop, Spark and related software. [Read More]