I have been running into some problems recently with 12cR2 databases and Kevin Clossons’ SLOB tool.
The SLOB setup.sh script allows for the concurrent loading of multiple schemas, and if you are loading a large amount of data, being able to load concurrently is a significant time saver.
With LOAD_PARALLEL_DEGREE set to 8, I got the following error:
ORA-27090: Unable to reserve kernel resources for asynchronous disk I/O
Linux-x86_64 Error: 11: Resource temporarily unavailable
Additional information: 3
Additional information: 128
Additional information: 140728056780720
These servers were new Dell R630s with plenty of horsepower, so the idea that just 8 parallel threads would cause this type of a failure was puzzling.
Further investigation of the trace file showed that the problem occured on the index shrink command:
SQL> SQL> ALTER INDEX i_cf1 SHRINK SPACE COMPACT
ERROR at line 1:
ORA-12801: error signaled in parallel query server P13L, instance
After some time investigating, it seems Oracle 12c has a much higher target for PARALLEL_MAX_SERVERS and PARALLEL_SERVERS_TARGET. In my case, PARALLEL_MAX_SERVERS had defaulted to 2240.
Since the SLOB data load uses the parallel query option, Oracle was spawning thousands of slave processes all trying to issue ASYNC IO.
So I set the numbers to what I considered more reasonable:
SQL> alter system set parallel_max_servers=400 sid='*';
SQL> alter system set parallel_min_servers=40 sid='*';
SQL> alter system set parallel_servers_target=400 sid='*';
Now SLOB was able to load data with eight concurrent processes.
Frequently I find I want to check what operating system is certified for which version of the database, and I can never remember the MOS note that explains it.
So here it is: MOS Note 1304727.1
Connect to My Oracle Support to access the note.
The Dell EMC Unity array is a capable mid-market platform able to support a variety of workloads.
In the all-flash configuration it delivers good performance for Oracle databases, and with the ability to support VVols is a good choice for databases virtualized with VMware ESX 6.
The following blog post walks you through adding VVol based shared storage for an Oracle 12c RAC using ASM and virtualized on VMware ESX 6.
Oracle currently ships 12cR1 (126.96.36.199) as the preferred install.
Being the R1 release it needs a lot of patching, and now many patches require OPatch 188.8.131.52, although the OPatch shipped with Grid 184.108.40.206 is in fact OPatch 220.127.116.11.3.
So you need to patch OPatch, before you can apply the patches you need to make 12cR1 work. Follow?
On this blog and elsewhere you will find UDEV rules examples for setting device ownership and naming consistency on older versions of Linux.
With RHEL7 some of the syntax has changed slightly.
This example was created using OEL7 with the Red Hat kernel, but should also work on Red Hat and CentOS.
This is an issue that keeps tripping me up in the development lab.
I create a quick database, and then after some time I go back to try to log in, and get:
ORA-28002: the password will expire within 7 days
And then I spend a while trying to figure out how to disable the password expiry component of the profile.
Here then, for my benefit as much as anyone else, is my quick guide to checking the user profile, and then disabling security components that cause headaches in the development lab.
I have stated this before. I am not a lawyer.
Neither am I an investment expert. Heck I ploughed money into Transocean two months before the Deepwater Horizon sank to the bottom of the Gulf and left a destructive oily mess all over the Gulf Coast.
So don’t take any stock picks from me.
But on a recent trip to the Midwest I met with a customer in an interesting predicament.