Oracle

(DESCRIPTION_LIST=(DESCRIPTION=(ADDRESS_LIST=(FAILOVER=YES)(LOAD_BALANCE=NO)

By Franck Pachot . Do you have complex connection strings with DESCRIPTION_LIST, DESCRIPTION, ADDRESS_LIST, ADDRESS and a nice combination of FAILOVER and LOAD_BALANCE? You probably checked the documentation, telling you that FAILOVER=YES is the default at all levels, but LOAD_BALANCE=YES(…)

Full page logging in Postgres and Oracle

By Franck Pachot . In my opinion, the volume of logging (aka redo log, aka xlog, aka WAL) is the most important factor for OLTP performance, availability and scalability, for several reasons: This is the only structure where disk latency(…)

V$MYSTAT delta values

By Franck Pachot . Here is a little script I use from time to time to look at V$MYSTAT values and displaying on one line a set of statistics with their delta value between two calls.

Server process name in Postgres and Oracle

By Franck Pachot . Every database analysis should start with system load analysis. If the host is in CPU starvation, then looking at other statistics can be pointless. With ‘top’ on Linux, or equivalent such as process explorer on(…)

JAN18: Database 11gR2 PSU, 12cR1 ProactiveBP, 12cR2 RU

By Franck Pachot . If you want to apply the latest patches (and you should), you can go to the My Oracle Support Recommended Patch Advisor. But sometimes it is not up-todate. For example, for 12.1.0.2 only the PSU is(…)

Multitenant, PDB, ‘save state’, services and standby databases

By Franck Pachot . Creating - and using - your own services has always been the recommendation. You can connect to a database without a service name, though the instance SID, but this is not what you should do. Each(…)

Result Cache: when *not* to use it

By Franck Pachot . I encountered recently a case where result cache was incorrectly used, leading to high contention when the application encountered a peak of load. It was not a surprise when I've seen that the function was called(…)

Testing Oracle SQL online

By Franck Pachot . Want to test some DDL, a query, check an execution plan? You need only a browser. And you can copy-paste, or simply link, your test-case in a forum, a tweet, an e-mail, a tweet. Here is(…)

Explain Plan format

By Franck Pachot . The DBMS_XPLAN format accepts a lot of options, which are not all documented. Here is a small recap of available information. The minimum that is displayed is the Plan Line Id, the Operation, and the Object(…)

Unplug an Encrypted PDB (ORA-46680: master keys of the container database must be exported)

By Franck Pachot . In the Oracle Database Cloud DBaaS you provision a multitenant database where tablespaces are encrypted. This means that when you unplug/plug the pluggable databases, you also need to export /import the encryption keys. You cannot just(…)