A reader asked an interesting question yesterday with regards to the previous post on the subject: where did you get your service metrics from when you queried v$servicemetric-PDB or CDB$ROOT?
I queried the PDB, but this morning repeated the test to make sure the results are consistent, and they are. This is definitely something you’d hope for: you should not have different results in the same v$-view depending on the container you execute your query (more...)
This is a follow-up on yesterday’s post about services in the new 12c database architecture. After having worked out everything I needed to know about TAF and RAC 12c in CDBs I wanted to check how FCF works with PDBs today. While investigating I found out that the Runtime Load Balancing Advisory does not seem to work as expected. To double-check, I ran the same test against a 12c non-CDB and noticed that the RTLB (more...)
In preparation of the OUGN Spring Seminar and to finally fulfill at least a part of my promise from July I was getting ready to research RAC, PDBs and services for my demos. It turned out to become a lot more interesting than I first assumed.
RAC and Multi-Tenancy
So the first attempt to really look at how this works has started with my 2 node cluster where I created a RAC database: RAC12C, administrator (more...)
I had the great fortune to have had many of my abstract accepted for upcoming conferences and other public appearances, the first ones for this year are these:
The first conference I’ll be attending is in Dublin, for OUG Ireland 2014 on March 11.I’m going to help out with RAC Attack and also present about Technologies for Developing Highly Available Applications in RAC 12c at 14:50 for about 45 minutes. What can you (more...)
I have come across this phenomenon a couple of times now so I thought it was worth writing up.
Consider a scenario where you get an alert because your standby database has an apply lag. The alert is generated by OEM and when you log in and check-it has indeed an apply lag. Even worse, the apply lag increases with every refresh of the page! I tagged this as an 11.2 problem but it’s (more...)
I have been asked to investigate another interesting problem worth writing about. It’s worth mentioning here because it deals with a problem I believed to have long since been solved: tablespace fragmentation. However, in this case it was a locally managed tablespace (LMT) with Automatic Segment Space Management (ASSM) enabled. It should be difficult to have fragmentation on one of these, but as you will see it is not impossible.
So the story started innocently (more...)
In my previous posts about the first RAC Grid Infrastructure Patchset I document a few issues I encountered that were worth noting. But where things work as advertised I am more than happy to document it too. In a way, the January 2014 GI PSU works as you’d hope it would (at least in my lab for my 2 node cluster).
I have a 2 node RAC cluster that hasn’t previously been patched. (more...)
I was actually hoping I had already written enough about applying the PSU for 126.96.36.199.0 but today I tried to apply the patch to my Oracle Restart home in my lab VM and guess what-it wasn’t as automatic as I thought.
I must have performed the classic copy & paste error and applied the patch to the GRID_HOME only. Please don’t do this! The README clearly states you can but if (more...)
Recently I have been asked to investigate the following error on an Exadata system.
ORA-64307: hybrid columnar compression is not supported for tablespaces on this storage type
Well, that’s simple I thought! Must be (d)NFS mounted storage, right? Everyone knows that you can have HCC on Exadata (and a few other storage products). So I looked at the problem and soon found out that the data files in question all resided on the cells. Here (more...)
I have already written about RAC/Grid Infrastructure related patching of 188.8.131.52.0 to 184.108.40.206.1, aka the October 2013 PSU for the database.
This post is a follow-up for pure RDBMS-only installations. I initially thought it wasn’t worth blogging about it (and hence the (more...)