19. 07. 2017.

Streams AQ: enqueue blocked on low memory while using Data Pump utility in 11.2.0.4

While helping with migration of one Retail production system, I need to export certain schemas by using Data Pump utility. As the database is pretty small (about 3TB), I’ve just execute expdp command and expected it will finish within 2 to 3 hours. When I checked in the evening, on my surprise, Data Pump job […]

09. 07. 2017.

RPM performance issue in push_back_error_rows procedure of rpm_future_retail_sql during the CC (conflict check)

After a while I’ve been called to solve RPM performance issue. While executing conflict check procedure in rpm_future_retail package, duration of one SQL inside the procedure push_back_error_rows takes 36 times longer than average. Here is the SQL text responsible for performance degradation, that I want to expose to be sure it’s not a simple problem: […]

06. 06. 2017.

DDL Against An Object Dependent On By A Synonym Invalidates The Synonym Object

It’s always the time to learn something new. If you missed to learn something during the day, it doesn’t mean you know everything. It just means you stop learning. In this case, I believe if I compile the package, that action won’t invalidate synonyms based on that package/procedure/function, as shown in the following example: create […]

29. 05. 2017.

ORA 7445 error and plsql_optimize_level

This is the typical example when compiler during the compilation of the source code, can introduce bugs, as Oracle has to re-arrange the code and make many modifications (optimizations like inline expansion etc.) of the code to achieve better performance. With higher level of optimization, compiler modifications will make will be more intrusive. The same […]

17. 05. 2017.

To patch or not to patch, that is the question

I’ve modify words spoken by Prince Hamlet (William Shakespeare) a bit to explain one of the most common asked questions regarding the patching strategy especially in today’s complex IT environment. Probably very larger company have their specific policy how often they need to patch their IT infrastructure (for example storage/network/OS/databases/App Servers…). Parts of IT infrastructure […]

08. 05. 2017.

ReIM Consolidated documents cost resolution – performance improvement

After external contractor of the company where I’m working and Oracle Support were not able to find solution that would improve performance of the ReIM consolidated documents functionality, it’s time for me to take that challenge. Very quickly I’ve found the problematic SQL. Here I’ll provide only the important part, as the query is over […]

02. 05. 2017.

Example of how 10x technically faster code is 1000x slower in production

Recently I’ve solved this interesting issue on Oracle Retail production (code is from RPM – Retail Price Management). After upgrading Oracle Retail I found problematic part of code that is running fine in the old version of the RPM. In new version, developer has correctly changed the following part of code with much faster version […]

24. 04. 2017.

RAC One Node and automatic database relocation

I know there are other places where you can find why you don’t want that Oracle cluster automatically relocate RAC One Node from one node to the other (only one node can be active in RAC One Node configuration). First I’d like to explain what reasons can be behind that. Those are the most common […]

10. 04. 2017.

High Performance Computing in Retail Industry

I’d like to invite you at HIPEAC (European Network on High Performance and Embedded Architecture and Compilation) conference in Zagreb, April 27-28, 2017. There I’ll have a presentation about how to build IT system and how HPC technologies like parallelism and clustering can help. This is excerpt from the announcement. Josip Pojatina, Solution Architect, mStart, […]

29. 03. 2017.

AIX ADAPTER HARDWARE OR CABLE error

Here I’ll describe what will happen if your sysadmin are going to restart VIO servers and not co-ordinate activities with DBA. Although you have multipath configured, VIO servers are critical for normal IBM AIX LPAR functionality, as they share HW devices to LPAR VMs. If you are having RAC or RAC One Node configuration, this […]