Delphix support helped me resolve an issue yesterday and the experience gave me the idea of writing this post about several general computer issue troubleshooting tips that I have learned down through the years. Never mind that I ignored these lessons during this particular problem. This is more of a “do as I say” and not a “do as I do” story. Actually, some times I remember these lessons. I didn’t do so well this (more...)
Database performance is in my jeans. Not my genes, I really do mean my jeans – an old pair of denim trousers. I look at my tatty attire keeping my legs warm and it reminds me of Oracle database performance.
You can buy jeans in a range of styles & sizes. Just as you can set up your database in a number of standard ways. When you create a database (more...)
A recent posting on OTN presented a performance anomaly when comparing a parallel “insert /*+ append */” with a parallel “create table as select”. The CTAS statement took about 4 minutes, the insert about 45 minutes. Since the process of getting the data into the data blocks would be the same in both cases something was clearly not working properly. Following Occam’s razor, the first check had to be the execution plans – when (more...)
I agree with many of the concepts and the aims of Agile, DevOps, Continuous Delivery etc. I find it hard to believe anyone wouldn’t see value in what they are trying to promote. As always, it is how people interpret and implement them that makes all the difference.
It’s just like religion. They all seem to (more...)
After we upgraded EM13c, I encountered a problem about automatically promoted listener targets. Since EM12c, I do not add/promote listeners. In earlier versions of EM12c, I had weird problems while monitoring listeners on RAC systems (such as they are detected down although they’re up). Since then, I don’t monitor them (specially SCAN listeners). In EM12c, when I remove a listener, it doesn’t promoted again. With EM13c, I see that listeners are discovered and promoted automatically (more...)
I’ve been discussing for years about the importance of network to database performance, especially once I started working on VLDBs, (Very Large Databases) but its a topic that often is disregarded. Now that I’m working more and more in the cloud, it’s become more evident the importance of the network to our survival.
For each and every cloud project I’ve been involved in, there is evidently going to be multiple challenges that turn to the (more...)
I based this blog post on information that I learned from this Oracle Support document:
Runinstaller And Emctl Do Not Work After Upgrading HP-UX 11.31 To 11.31 Update3 (Sep 2008) (Doc ID 780102.1)
My situation was slightly different from what Oracle’s note describes so I thought it would be helpful to document what I found.
In my case I am cloning an Oracle 10.2.0.3 home on to a fully (more...)
According to the Oracle 12cR1 documentation and concepts, it is 100% clear that there can be only one UNDO tablespace in a multitenant architecture and it is at CDB level; thus, a PDB cannot have any UNDO tablespace.
Are we really sure about that? Let’s test it!
First, we need a PDB with few tablespaces:
FRED_PDB> select NAME, OPEN_MODE, CON_ID from v$pdbs ; NAME OPEN_MODE CON_ID -------------------------------------------------- ---------- ---------- FRED_PDB READ WRITE (more...)
Troubleshooting connection issues with Oracle SQL*Net can be difficult at times due to the many options that can be taken during configuration. One of the options is where the file tnsnames.ora may be found. There are multiple locations available, and at times there is justification for having more than one copy of the file.
Perhaps there is a hybrid database naming configuration. Say there are a number of company-wide databases that are defined (more...)
I was installing another Exadata last month when I got an error on create cell disks step. I’ve seen the same error before when I was extending two to three rack Exadata configuration but thought it was one-off.
The cell disk creation failed as below:
[root@exa01db01 linux-x64]# ./install.sh -cf Customer-exa01.xml -s 8 Initializing Executing Create Cell Disks Checking physical disks for errors before creating celldisks......................... Restarting cell services.................................................... ERROR: Stopping the RS, CELLSRV, (more...)
This is just a little example of thinking about hinting for short-term hacking requirements. It’s the answer to a question that came up on the Oracle-L listserver a couple of months ago (Oct 2015) and is a convenient demonstration of a principle that can often (not ALWAYS) be applied as a response to the problem: “I can make this query work quickly once, how do I make it work quickly when I make it part (more...)
Here’s the latest video on my YouTube channel. This one is a quick run through of RDS for Oracle, a DBaaS offering from Amazon Web Services.
If you are not into the video thing, you can see the article this video was based on here.
Galo Balda has now joined the illustrious list of people who have said “.com” on one of my videos.
This past week the topic of archiving came up - the thing that everyone talks about but no-one does....
One of the topics that came up was that old partitions could be exchanged out of the main table and stored away from the main table to help in certain performance cases - we would still like access to them and the ability to switch it back in if required - we do not want it (more...)
WordPress 4.4.2 has been released.
You can see the list of fixes here. Three of the five installations I maintain had already updated by the time I got to them, so by the time you read this you will probably already have it too.
WordPress 4.4.2 was first posted on February 2, 2016 at 8:30 pm.
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