The Flash Insider: To POC or Not To POC?

Proof of Concept?

Guest Post

I’m excited announce another guest blog written by my good friend and funny-talking American cousin Nathan Fuzi. Like me, Nate comes from a database background but joined the all-flash storage revolution back in its infancy. Which means, like me, Nate how has a little tombstone on his résumé marked Violin Memory. But even though he has since moved up to working in THE CLOUD, Nate’s experience working for an AFA vendor is invaluable. Over six years, he worked (more...)

Long Parsing and PGA limits

Recently I’ve seen not so smart optimizer behavior: one query took long time to parse, and ended with an error hitting PGA_AGGREGATE_LIMIT in few minutes; another query was just parsed for ages while using reasonable (under 2G :)) amount of PGA and still could hit PGA_AGGREGATE_LIMIT but after way more time – up to an hour.

Both cases were similar and involved queries which were accessing views; and those views’ code is generated by an (more...)

Oracle Database Result Cache Troubleshooting

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...)

MobaXterm 10.0

MobaXterm 10.0 was released a couple of days ago. As well as the usual bug fixes there are a number of enhancements and a new flatter look and feel.

Downloads and changelog in the usual places.

Happy upgrading!



MobaXterm 10.0 was first posted on February 20, 2017 at 8:39 am.
©2012 "The ORACLE-BASE Blog". Use of this feed is for personal non-commercial use only. If you are not reading this (more...)

eDB360 includes now an optional staging repository

eDB360 has always worked under the premise “no installation required”, and still is the case today – it is part of its fundamental essence: give me a 360-degree view of my Oracle database with no installation whatsoever. With that in mind, this free tool helps sites that have gone to the cloud, as well as those with “on-premises” databases; and in both cases not installing anything certainly expedites diagnostics collections. With eDB360, you simply connect to (more...)

How to speed up slow unicode migration of a table with xmltype columns

Recently I have had an issue with slow unicode migration of the database upgraded from 10g to The main problem was a table with xmltype: we spent about 4 hours for this table(~17GB) during test migration, though all other tables (~190GB) migrated just for about 20 minutes.
We used DMU(Database Migration Assistant for Unicode), and the root cause of the problem was update statement generated by DMU for this table:

update   (more...)

Data Pump or Data Pain Part04 – The End

Please take a look at my notes below:
DataPump: Schema/DB Migration Notes

Duplicate constraints are impossible right ?

Here’s a very simple example of a table called PARENT being a (surprise surprise) parent in a referential integrity relationship to a (drum roll for my choice of name) CHILD table

SQL> create table parent ( p int, constraint PAR_PK primary key (p) );

Table created.

SQL> create table child ( c int,
  2        p int
  3      );

Table created.

SQL> alter table child add constraint fk1 foreign key ( p ) references parent (  (more...)

The Great Wall

I went to see The Great Wall last night.


The critics gave it a hard time. The reviews aren’t great. It’s a really cool film!

OK, it doesn’t have the best story. The character development isn’t great. The progression of Matt Damon’s character is quite clumsy. I see the flaws in all that, but my gosh what visuals!

If you are going to watch this film I would suggest watching it on the biggest (more...)

Optimising AWS for Oracle – Licenses

If you're keeping an eye on the Oracle license rules you'll know that you need to make sure that when you're designing in AWS you make the most of every CPU that has an Oracle license attached too it.

Here's our rundown of how to design and use AWS features to maximise those licenses.

  • Design for zero waste. In the past we might have Oracle nodes that didn't do very much. Those DR servers, or (more...)

The real question is … why are you NOT blogging

Colleague Jeff Smith published an interesting post the other day about his “rules and regulations” for blogging, but the overriding theme (Ed: – this is my opinion, I’m not speaking for Jeff)  was that the “what” he blogs about was – anything he’s passionate about, and the “when” was – whenever felt inspired to do so.

That got me thinking about blogging in general.  I think it is safe to say

Simple Python for Oracle database tuning example

I ran across a stackoverflow question and it gave me an idea for a simpler use of Python to graph some Oracle database performance information. I looked at my PythonDBAGraphs scripts and I’m not sure that it is worth modifying them to try to simplify those scripts since I like what they do. But they may make people think that Python scripts to graph Oracle performance data are difficult to write.  But, I think if someone (more...)

Truncate 12c

Here’s one of those little improvements in 12c (including 12.1) that will probably end up being described as “little known features” in about 3 years time. Arguably it’s one of those little things that no-one should care about because it’s not the sort of thing you should do on a production system, but that doesn’t mean it won’t be seen in the wild.

Rather than simply state the feature I’m going to demonstrate it, (more...)

Creating a RAC 12.1 Data Guard Physical Standby environment (4)

In the previous three parts of this series a lot of preparation work, needed for the configuration of Data Guard, was performed. In this part of the mini-series they all come to fruition. Using the Data Guard broker a switchover operation will be performed. A couple of new features in 12c make this easier. According to the “Changes in This Release for Oracle Data Guard Concepts and Administration” chapter of the 12.1 Data Guard (more...)

Oracle Upgrade/Migration : What method are you using?

I tweeted a couple of days ago about an important upgrade/migration I was doing yesterday. I was moving a smallish, but high profile, database from Oracle 11g on HP-UX Itanium to Oracle 12c on Oracle Linux inside a VMware VM. Almost immediately Joey D’Antoni came back with the question, “What method are you using?” I thought it might be worth writing a little something about the decision process.

When you are deciding how to upgrade (more...)

Data Pump or Data Pain Part03 – user/db object

You might be thinking, why is it necessary to specify schemas versus perform full import or why create SQL file?

$ cat impdp_full02_user.par

userid="/ as sysdba"

There are 5 users imported which correspond to EXU8USR view.
If users already exists in the new database, wouldn’t create user just fail?

From demo below #schemas=GGS_ADMIN,DEMO (commented) which will

$ impdp parfile=impdp_full02_user.par

Import: Release 11. (more...)

Log Buffer #504: A Carnival of the Vanities for DBAs

This edition of Log Buffer covers Oracle, Microsoft SQL Server, and MySQL.


Data Pump or Data Pain Part02 – tablespace/user

Monday Spotlight: It’s About Security – Oracle Exadata SL6 copy

OGG Custom Adapters: How to include a unique identifier for every record in custom adapter?

One of the optimizer enhancements that appeared in 12.2 for SQL is the “band join” that makes certain types of merge join much (more...)

Performing in the cloud – network latency

To me, ‘cloud computing’ is renting a compute resource to perform a task. In order to use that compute resource, you need to instruct it to do something, which is typically done via the network. If the task the compute resource needs to fulfil is being an application server or being a client or both in the case of an application server that uses an Oracle database, the network latency between the client of the (more...)

Even More 12.2 Features

A few days ago I was browsing the documentation and suddenly realized that I haven’t gone over the 12.2 books. One of the things I like to do is reading the “New Features” guide, so I did. After writing about the major features, here are some smaller ones, but still important enough to know. Transparent … Continue reading Even More 12.2 Features

Goldengate 12c runInstaller UNIX_GROUP_NAME | INVENTORY_LOCATION

I keep finding ways to break things because the environments are not consistent.

This parameter is the UNIX group name to be set for the inventory on UNIX platforms.
Note: The UNIX group name is used for first-time installations only.

Details for oraInventory

$ cat /etc/oraInst.loc

Notice the group is dba while /etc/oraInst.loc has oinstall.
Probably because I specified UNIX_GROUP_NAME=dba?
Don’t remembered since this environment is really old.

$ ls -ld  (more...)