Weekend Learning: Investigating correct setting of SESSION_CACHED_CURSORS and OPEN_CURSORS parameters

Take a few moments this weekend to visit document ID 208857.1 in My Oracle Support to brush up on this "SCRIPT - to Set the 'SESSION_CACHED_CURSORS' and 'OPEN_CURSORS' Parameters Based on Usage" so that you can help make your databases a bit more proactive by monitoring this on a regular basis!

12c: Cursor wait with In-Memory and Parallel queries running

I think it is interesting that the MOS article "Significant 'Cursor: Pin S Wait On X' Waits When Using In-memory Column Store and Parallel Query" via note ID 1910787.1 is saying there is a serious bug with 12.1.0.2 where you try to query data in parallel with In-Memory options enabled.  I would say the whole point of 12c is the In-Memory store, but remember that In-Memory is an option that came after 12c was introduced so really it is not that surprising that we will start seeing some of these one-off bugs start rattling out of early adopter systems!

R12.2.3: Workflow Java Deferred Listener down due to maximum open cursors

Planning for the future, I am bookmarking article "R12.2: Workflow Java Deferred Listener Goes with java.sql.SQLException: ORA-01000 ,WF_EVENT_OJMSTEXT_QH.ENQUEUE on Maximum Open Cursor" in MOS via ID 1966450.1 so I can make sure to get this problem into our testing suite before we are ready to upgrade onto R12.2.3!  Also, I am going to be using the script provided so I can start looking for open cursors in our system as I never knew about the v$open_cursor table until now!

Weekend Learning: JDBC driver cursor leak on 11.2.0.4

Do you know how sometimes you can stumble across a solution for a problem, when you are not even looking for it?  Well let me introduce you to My Oracle Support document "Cursor Leak After Upgrading to JDBC Driver 11.2.0.4" via note ID 1939530.1 and ask if you have been having problem with "middleware" or "web services" after upgrading to 11.2.0.4?  We are not on 11.2.0.4 YET, but on 11.2.0.3 we have had some issues with memory leaks so this type of issue could be the next condition we encounter so now I am aware of it and can potentially start looking for it when we start upgrading (and testing).  Luckily we have not had the ORA-01000 errors indicated in this article, but forewarned is forearmed.

Cursor sharing and RMAN errors on 11.2.0.2

Tonight I learned that if you have the gv$parameter cursor_sharing set to FORCE or SIMILAR on an 11.2.0.2 platform RMAN may spit out some odd ORA-01008 or ORA-07445 error messages.  My Oracle Support article "ORA-01008: RMAN backup fails with Assorted Errors on 11.2.0.2 if cursor sharing is enabled" via note ID 1472116.1 has all the details including the patch you need to apply in order to avoid "resolving" this by flushing the shared pool all the time.

Child cursors

Christian Antognini presents us with an existential database question asking how many children can a parent cursor have.  What I find the most interesting about this, is how the answer to that question differs based on what database version you have as well as what bug patches you've applied.  Again, I haven't had to encounter issues regarding this but it will be in the back of my mind going forward.