Approximate Query Processing appears to be a major feature of Oracle Database 12c Release 2 SQL. In 12cR1 patchset 2 (188.8.131.52), we saw one approximate query function appear – APPROX_COUNT_DISTINCT to use instead of COUNT(DISTINCT). In 12.2 there are several APPROX functions introduced: APPROX_COUNT_DISTINCT_DETAIL APPROX_COUNT_DISTINCT_AGG TO_APPROX_COUNT_DISTINCT APPROX_MEDIAN APPROX_PERCENTILE APPROX_PERCENTILE_DETAIL APPROX_PERCENTILE_AGG TO_APPROX_PERCENTILE According to Oracle […]
Topic of this blog is a nice new feature in 12c, not the plsql package I built that’s using it. So here’s the story..
For one of our customers we needed to have a simple schema comparison tool that would be able to check, as part of application deployment activity, whether there is any discrepancy between the schema that was used to build the application (.ear) files and the target schema of the deployment. Of (more...)
Changing The Number Of Oracle Database 12c Log Writers
In an Oracle Database 12c instance you will likely see multiple log writer (LGWR) background processes. When you first start the Oracle instance you will likely see a parent and two redo workers. This is a very big deal and something many of us have been waiting for - for many years!
While I'm excited about the change, if I can't control the number of LGWRs (more...)
Off May Not Be Totally Off: Is Oracle In-Memory Database 12c (184.108.40.206.0) Faster?
Most Oracle 12c installations will NOT be using the awesome Oracle Database in-memory features available starting in version 220.127.116.11.0. This experiment is about the performance impact of upgrading to 12c but disabling the in-memory features.
Every experiment I have performed comparing buffer processing rates, clearly shows any version of 12c performs better than 11g. (more...)