I’ve gotten a lot of reports of folks branching out into SLOB 2.2 large user count testing with the SLOB 2.2 Think Time feature. I’m also getting reports that some of the same folks are not getting the resultant AWR reports one expects from a SLOB test.
If you are not getting your AWR reports there is the old issue I blogged about here (click here). That old issue was related to a (more...)
This is the second part of a series of blogpost on Oracle database PGA usage. See the first part here. The first part described SGA and PGA usage, their distinction (SGA being static, PGA being variable), the problem (no limitation for PGA allocations outside of sort, hash and bitmap memory), a resolution for Oracle 12 (PGA_AGGREGATE_LIMIT), and some specifics about that (it doesn’t look like a very hard limit).
But this leaves out Oracle version (more...)
The default value of METHOD_OPT from 10g onwards is ‘FOR ALL COLUMNS SIZE AUTO’.
The definition of AUTO as per Oracle documentation is :
AUTO: Oracle determines the columns to collect histograms based on data distribution and the workload of the columns.
This basically implies that Oracle will automatically create histograms on those columns which have skewed data distribution and there are SQL statements referencing those columns.
However, this gives rise to (more...)
It seems that I’m getting more and more drawn into the world of performance analysis, and since I sometimes tend to forget things I need to write them down. I almost enjoy the “getting there” more than ultimately solving the problem. You pick up quite a few things on the way.
This environment is Exadata 126.96.36.199.1/Oracle 188.8.131.52 but as with so many things the fact that the database (more...)
As Turkish Oracle User Group (TROUG), we will organize our second meeting in Ankara on December 23rd. The event will be held at the Chamber of Electrical Engineers (EMO). The main theme of the meeting is Oracle 12c. There will be 4 sessions about new features of Oracle 12c (Database In-Memory, Active Data Guard, RAC and Flex ASM and Multitenancy). I usually do presentations about Enterprise Manager but this time, I have picked a more (more...)
We are discussing the management of Oracle Database 12c in Oracle Enterprise Manager 12c. In our previous blog posts on this topic, we came to the Provision Pluggable Databases page as seen below. This is accessible via the Container Database Home Page in Enterprise Manager 12c, from the Oracle Database menu.
When it comes to licensing for this page, it needs to be clearly understood. The licensing requirements for the Enterprise Manager Database Lifecycle Management (more...)
In the last post, we saw what the discovery of an Oracle 12.1 Container Database (CDB) would look like in Oracle Enterprise Manager 12c, with the CDB and component PDBs all being discovered by the EM Agent that has been installed on the target database server.
Drilling down to a CDB, the following screenshot illustrates how the CDB Home page would appear. The Home Page shows the list of Pluggable Databases in (more...)
A friend from a lovely country in South America wrote to me :
“Hi My Friend!! My colleague has installed an Oracle Database 12c Container database (CDB) and he has created 2 Pluggable databases (PDBs) on it. He is keen to manage the CDB and PDBs in Enterprise Manager.
“But, when he adds the database to Enterprise Manager 12c, he sees it like a non-CDB and there is no way to work with PDB’s (in (more...)
This year the Northwest Oracle User Group created a scholarship for an outstanding female student in the Portland State University Computer Engineering Department. The criteria was straight-forward. In addition to being an outstanding student we asked all the applicants to answer this question:
“How does employee participation in professional communities add value for their employers?”
The arguments for promoting WIT are well-documented elsewhere, and it had a bearing on our decision. But we also (more...)
This post is about memory management on the operating system level of an Oracle database. The first question that might pop in your head is: isn’t this a solved problem? The answer is: yes, if you use Oracle’s AMM (Automatic Memory Management) feature, which let’s you set a limit for the Oracle datababase’s two main memory area’s: SGA and PGA. But in my opinion any serious, real life, usage of an Oracle database on Linux (more...)
A couple of weeks back I received an update on my “4k bug” SR (slow multirow DML performance for small block sizes). As it turns out, the observed behavior is not a bug. It’s actually more interesting than that. It is an undocumented feature that controls the insert mode depending on the estimated row size (the sum of all column sizes). If the estimated column size exceeds the size of the block, then Oracle switches (more...)
I saw a tweet by Simon Haslam at the weekend that read,
“I’m v surprised to read that @Atlassian Stash needs newer git than in the latest RHEL/OL6 repos!”
I had a similar experience at the weekend too, but this time with Oracle REST Data Services (ORDS) 3.0 EA. According to the documentation, it requires the following version of Tomcat.
“Apache Tomcat Release 7.0.56 or later”
So let’s have a look (more...)
Purpose is to demonstrate how to create HA for Bi-Directional Replication Goldengate installed on ACFS with RAC cluster using XAG.
XAG simplifies the process since there are no requirements to create action scripts.
Please review REFERENCE section for versions used in test case and versions requirements.
Goldengate is installed on ACFS for simplicity; otherwise, at a minimum the following directories br, dirchk, dirdat, dirtmp will need to be on shared storage with symbolic links if (more...)
Sorry it’s taken a couple of days to finish off this series of blog posts on UKOUG Tech 14. I had expected to get some time on the trip back to write this, but as you’ll see if you keep reading, that really didn’t happen. So let’s go back to Day 3 of the conference.
I started the day by attending Patrick Hurley’s “Adventures in Database Administration” session. This was quite different to the normal (more...)
Anyone that has ever coded PLSQL will be familiar with the error ORA-4068, where you had some state persisted in a session due to a package variable, and then when you change the package, the state is cleared along with an ORA-4068. Here’s a quick example:
SQL> create or replace
2 package PKG is
3 procedure P;
SQL> create or replace
2 package body (more...)
AZORA is planning a meeting January 20th. Here is the link to RSVP: url
Hope to see you there.
One of the many interesting things I heard at the conference this time around was that Oracle’s future direction includes the use of database files on ACFS. When ACFS came out this was strictly ruled out, but has been possible for a little while now, I believe with 184.108.40.206.0. With the Oracle Database Appliance (ODA) using this deployment option and hearing about it at the conference, a little further investigation was (more...)
Here’s a query (with a few hints to control how I want Oracle to run it) that demonstrates the difficulty of trying to solve problems by hinting (and the need to make sure you know where all your hinted code is):
leading (@main t1@main v1@main t4@main)
select /*+ qb_name(inline) no_merge */
t2.n1, t3.n2, count(*)
from t2, t3
where exists (
select /*+ qb_name(subq) no_unnest push_subq */