I was troubleshooting an issue where the Oracle Database Result Cache did not get used when the RESULT_CACHE hint was specified inside a subquery. As the main query has a sysdate inside, the RESULT_CACHE Hint can not be specified for the main query, but only for the subquery.
SELECT SQ.*, sysdate FROM
(SELECT * FROM tableX, ....) SQ;
When using “/*+ RESULT_CACHE */ inside of Subquery, result cache was not (more...)
During the Upgrade of Oracle Linux 7.2 to 7.3 with “yum update”, when updating the microcode_ctl package, the system crashed and firmware reported an uncorrectable CPU error after reboot.
It turned out that the update of the package in combination with specific Intel CPUs causes the issue. In the meantime, there is a red hat bug and solution available.
- MOS: The system could (more...)
I recently had an issue where a database with 240GB SGA (1 huge shared memory segment) configured with hugepages on a system with 512G RAM was suddenly becoming instable and new logons were denied with these error message:
ORA-01034: ORACLE not available
ORA-27123: unable to attach to shared memory segment
Linux-x86_64 Error: 22: Invalid argument
Additional information: 2667
Additional information: 1736718
Additional information: 215016800256
This was strange because ipcs -a showed all shared memory segments (more...)
In previous versions, it was “best practice” to always get the most current opatch (patch 6880880) from MOS. Unfortunately, with Enterprise Manager Cloud Control 13c, this is problematic at the moment. The reason is that OMS 13.1 is shipped with OPatch 13.6:
[oracle@em13c ~]$ opatch version
OPatch Version: 184.108.40.206.0
Currently, OPatch 13.6 is not available in MOS. Only OUI Nextgen (more...)
When trying to patch OMS 220.127.116.11 in a VirtualBox environment with latest OMS PSU, I came across a strange problem which took quite a while to solve. The opatchauto apply and also -analyze commands failed every time with this error after several minutes of hanging:
opatchauto failed with error code 231
Manual connect to WLS console with relevant protocol/host/port/username/password was working fine. Then I realized that there was an issue with the (more...)
During implementation of AWR Warehouse, I discovered that AWR warehouse is using temporary staging schemas in the AWR warehouse repository database. These schemas life approximately for the duration of a datapump import job and are then dropped again. Due to the fact that the used password is not compliant with customers password verification function, the jobs failed.
v_sql := ‘ CREATE USER ‘ || STAGING_SCHEMA || ‘ IDENTIFIED BY SYS_GUID ‘ ||
‘ DEFAULT TABLESPACE (more...)
For one of my clients, I experienced several issues with applying PSU 18.104.22.168.5 with opatch 22.214.171.124.9.
There were some code changes in opatchauto, which are not yet production-ready. I am looking forward to seeing a new opatch release (maybe 126.96.36.199 or 11) which has these issues fixed.
Bug 22091017 : OPATCHAUTO -ANALYZE COMMAND SHUTS DOWN THE RDBMS HOME IN 12C
“opatchauto apply -analyze” is (more...)
Customers have been waiting for a Standard Edition release for version 188.8.131.52. Then, in July, a support engineer leaked that there will be a whole new type of “Edition”, called “Standard Edition 2″ to replace both “Standard Edition” and “Standard Edition One”. The respective MOS Note disappeared shortly after the accidental publication. Now today the release finally became official and can be downloaded via OTN. The “SE2″ is priced exactly as the (more...)
There is one very interesting feature of Microsoft Hyper-V called Replica, which allows replication of Virtual Machines without shared storage. With Hyper-V Replica, one can set up Oracle Database VMs to replicate between independent nodes. This document (in german) describes the setup in more detail:
Hyper-V Replica für Oracle Database
On the presentations page you can find the my presentation material from DOAG regional meeting September 2014 in Munich about “Enterprise User Security”.
I’m sharing this in the hope of saving someone from an unwelcome surprise.
I recent upgraded an Exadata system from 184.108.40.206.1 to 220.127.116.11.1. Apart from what turns out to be a known bug that resulted in the patching of the InfiniBand switches “failing”, it all seemed to go without a snag. That’s until I decided to do some node failure testing…
Having forced a node (more...)
The following is a list of changes I noted during installation of Oracle Linux 7. I imagine the same will apply to Red Hat Enterprise Linux 7, but I haven’t verified that to be the case.
Setting the Hostname
I was accustomed to updating /etc/sysconfig/network with the hostname of my machine as documented here for Oracle Linux 7. I did this and was then surprised to find that my hostname was not picked up. On returning (more...)
- Enterprise Manager 12c (EM) installed and agents rolled out to database servers
- Access to EM offered to development teams with the primary purpose of allowing them to investigate application related database performance issues
The EM documentation covers a selection of privileges you might want to grant to users in database targets in order to allow them to be used for accessing EM functionality. The privileges mentioned are:
- SELECT ANY DICTIONARY
- CREATE SESSION
- EXECUTE on (more...)
When creating VMs on my laptop I like to configure the minimum number network interfaces. I also tend to end up with environments where I want multiple VMs to be able to see each other, see the internet and see my physical host. It seems many people using VirtualBox use the approach of having a “Host-only Adapter” interface and a “NAT” interface. The only reason I have for not liking this is that it (more...)
I’ve previously written about a problem I encountered when kdump is configured to write to an NFS location with UEK (in Exadata software version 18.104.22.168.1). I’m please to report that the root cause of the problem has been identified and there is a very simple workaround.
There were some frustrating times working this particular SR, the most notable being a response that was effectively, “It works for me (and so I’ll (more...)
I’ve touched on this issue before over at my previous blog and also talked about it at UKOUG Tech13. The presentation at Tech13 was more than 90% demos so hasn’t left a lasting record of the issue and the previous blog post doesn’t go into significant detail. I think it (more...)
Removing a service via srvctl has not historically resulted in the service being fully removed from the database and it would still be visible in DBA_SERVICES as show below in an 22.214.171.124 database:
Create the service:
$ srvctl add service -d orcl -s demo -r "ORCL1,ORCL2"
There were problems that affected UEK and NFS when 126.96.36.199.1 was initially released (as covered by Andy Colvin). As mentioned in the comments of Andy’s post: Oracle released an updated ISO with fixes for this problem (patch 16432033).
There were also problems with kdump not (more...)
If like me, and a couple of others I’ve spoken to recently, you were not previously aware of “sudo -s” then you might be interested to know that you can save yourself two keystokes by switching from:
sudo su -
From the man page:
The -s (shell) (more...)