Oracle

Understanding Oracle Parallel Execution in 11.2 is a pain, not because the topic itself is overly complex, rather because Oracle made it much more complicated than it needed to be. Basically, the main initialization parameter that controls the parallel execution is PARALLEL_DEGREE_POLICY. According to Oracle online documentation, this parameter can be set to: MANUAL: Disables automatic degree of parallelism, statement queuing, and in-memory parallel execution. This reverts the behaviour of parallel execution to what it was prior to Oracle Database 11g Release 2 (11. [Read More]

Some bugs in Oracle’s code are really surprising. Whenever I run into this kind of issue, I can’t help but wonder how nobody else noticed it before. Some days ago I was querying AWR data from DBA_HIST_SYSMETRIC_SUMMARY and I wanted to turn the columns AVERAGE, MAXVAL and MINVAL into rows, in order to fit this result set into a performance graphing application that expects input data formatted as {TimeStamp, SeriesName, Value}. [Read More]