Dear readers This time I'm not presenting you any of my own work but instead want to advertise what my CSA colleague Tobias Kaufmann just published here on SCN: Automatic Test of Queries with RS Trace Tool. (really well done Tobias!) Given how important the correctness and well working (concerning results and performance) of SAP … Continue reading Automatic testing of BW queries, anyone? Here you go!
As the fourth quarter of the year started everybody seems to check the goals that had been set for this year and what has already been reached. Looking back on the messages I worked on I found a very clear pattern, when the message was about BW on Oracle and performance. Most messages were solved … Continue reading How most BW performance support messages are solved
Last week a colleague from the WHM (data warehouse management) support team called me to get some assistance with a customer message he was processing. The customer complained about short dumps with the infamous "TSV_TNEW_BLOCKS_NO_ROLL_MEMORY" error, which is basically the way an ABAP work process reports that it ran out of memory. Checking the short … Continue reading SAP Support case “FOR ALL ENTRIES disaster”
Let's have a contest! One of my last blog posts started off a discussion (e.g. Bala posted his thought in a blog) about the importance of the partitioning feature for an SAP BW installation. No doubt about it - partitioning is something we use heavily for SAP BW. Breaking the work down into smaller pieces … Continue reading Partition count contest!
One of the quotes I like most I learned from Tom Kyte from Oracle. It's one from Artemus Ward: "It ain't so much the things we don't know that get us into trouble. It's the things you know that just ain't so." This blog post is about one of those cases. A customer complained about … Continue reading Short note on Line Item and High Cardinality dimensions
Welcome to the problem As usual understanding, the meaning and the scope of the question is key for the answer to this question, recently filed by a customer. So, what is the customer complaining about? What does he mean by "partition pruning"? It's a feature of the query optimizer to figure out, which partitions of … Continue reading Question to SAP Support “Why is partition pruning not working in my BW on Oracle?”
Lately, I've been confronted with several customer messages concerning problems with Infocube compression, change runs or roll-ups. For some reason, these standard BW actions, that worked the day before, now started to fail. The first step in cases like these is, of course, to find out, why the actions fail. The usual starting point for … Continue reading BW/DB Support 101 – Get to know your failing SQL statement
For many BW performance relevant DB-features, it's really all about the details of usage and implementation when it's about the effect of those features. The following are two examples of rather small things that went wrong which had a big impact on the system performance. Two examples for BW on MaxDB The first two examples … Continue reading Small changes with big effects
Ok, once again reproducing a problem takes a lot of (waiting-)time for the query to finish. In the meantime I can also just write a super-short-blog post about a pretty common BW-on-Oracle performance hunch: Inappropriate database optimizer statistics. (yes, 'inappropriate' not 'outdated'!) Usually, that means: if everything runs as it is supposed to, BW will … Continue reading BW on Oracle: a performance hunch I see more and more often…
In the second week working in BW support, I noticed that there was a problem reported by customers again and again. The customers complained about "database statistics update fails in process chains" or "brconnect run returns errors". When checking the relevant log file entries for the actions there was always something like ERROR at line … Continue reading A first (BW) issue…