A quick post to let you know about the two presentations that I’ll be doing at Oracle Open World 2014.
Session ID: UGF4482
Session Title: “Getting Started with SQL Pattern Matching in Oracle Database 12c“
Venue / Room: Moscone South – 301
Date and Time: 9/28/14, 13:30 – 14:15
Session ID: CON4493
Session Title: “Regular Expressions (more...)
A comment on one of my early blogs about the 12c in-memory database option asked how Oracle would deal with read-consistency. I came up with a couple of comments outlining the sort of thing I would look for in a solution, and this note is an outline on how I started to tackle the question – with a couple of the subsequent observations. The data is (nearly) the same as the data I generated for my previous article on the (more...)
Oracle’s 184.108.40.206 was released a few weeks ago (You can download it from OTN here: Oracle 220.127.116.11 Download). While technically a minor point release, it contains a couple of major features that would normally be rolled out in a more substantial version change like 12cR2 or perhaps V13. Of course the most highly anticipated feature is a new option (Oracle In-Memory Option) that provides a column (more...)
One of the really cool new features introduced in 18.104.22.168 is Attribute Clustering. This new table based attribute allows you to very easily cluster data in close physical proximity based on the content of specific columns. As I’ve discussed many times, indexes love table data that is physically clustered in a similar manner to the index […]
Over the last two weeks I’ve been working on a heartbeat monitoring solution for a client. This is not the normal heartbeat solution provided by Oracle as described in note 1299679.1; yet very similar. The approach that I configured is similar to a traditional heartbeat setup but uses the same extract and replicats already being used by the database/application. For simplicity reasons, I like to call this approach an Integrated Application Heartbeat.
In order (more...)
The title of this piece is the name given to a new feature in 22.214.171.124, and since I’ve recently blogged about a limitation of the in-memory option I thought I’d pick this feature as the next obvious thing to blog about. This is a bit of a non sequitur, though, as the feature seems to have nothing whatsoever to do with the in-memory option; instead it’s a cunning mechanism combining aspects of the star-transformation (but without the bitmap indexes), (more...)
If you have done any play with the latest release of Oracle database 12c, you must have come across the concept of Common and Local users. I won’t rewrite what’s already there in the docs but for setting the context of the post, a Common user must be created with a prefix added to the username-C##. Miss that and you won’t be able to create one while being connected to the Container database. On (more...)
OTech Magazine – Summer 2014
The fourth issue of OTech Magazine, the independent magazine for Oracle professionals, is available. For the summer 2014 issue there are some more personal articles included. Titles vary from The Spiritual Programmer to The Next Generation: Oracle SOA Suite 12c and back via How to protect your sensitive data using Oracle Data Vault.
Download OTech Magazine – Summer 2014 here.
In a recent article, I discussed how to configure the SOA Suite 12c for sending emails using GMail: http://technology.amis.nl/2014/08/05/setup-gmail-as-mail-provider-for-soa-suite-12c-configure-smtp-certificate-in-trust-store/. An interesting aspect of that configuration is the loading of the GMail SSL certificate into the Keystore used by WebLogic, in order for the SSL based interaction with GMail to successfully be performed. The configuration of GMail for inbound interactions requires a similar procedure for the certificate for the imap.gmail.com server.
I’ve been struggling to find time to have any interaction with the Oracle community for the last couple of months – partly due to workload, partly due to family matters and (okay, I’ll admit it) I really did have a few days’ holiday this month. So making my comeback with a bang – here’s a quick comment about the 12cR2 in-memory feature, and how it didn’t quite live up to my expectation; but it’s also a comment (more...)
Just a quick post on a new Exadata feature called Zone Maps. They’re similar to storage indexes on Exadata, but with more control (you can define the columns and how the data is refreshed for example). People have complained for years that storage indexes provided no control mechanisms, but now we have a way to exert our God given rights as DBA’s to control yet another aspect of the database. Here’s a link to the (more...)
In enterprises, LDAP servers are often used to store user credentials and groups and share them among applications. Oracle SOA Suite 12c introduces a new technology adapter; the LDAPAdapter which allows easy integration with LDAP servers. In this blog post I will provide a quick and easy howto on installation of an LDAP server and browser (ApacheDS and Apache Directory Studio). I will also describe the configuration required to use the LDAPAdapter and provide an (more...)
Counting the number of distinct values (NDV
) for a table column has important
applications in the database domain, ranging from query optimization to optimizing reports for large data warehouses. However the legacy
SQL method of using SELECT COUNT (DISTINCT <COL>) can be very slow
. This is a well known problem and Oracle 126.96.36.199 provides a new function APPROX_COUNT_DISTINCT implemented with a new-generation algorithm to address this issue by providing (more...)
Every once in awhile when I restart an extract, I see entries in the report file that reference “Bounded Recovery”. What exactly is “Bounded Recovery”?
First, keep in mind that “Bounded Recovery” is only for Oracle databases!
Second, according to the documentation, “Bounded Recovery” is a component of the general extract checkpointing facility. This component of the extract guarantees an efficient recovery after an extract stops for any reason, no matter how many uncommitted transactions (more...)
I suggested a little while ago that thinking about the new in-memory columnar store as a variation on the principle of bitmap indexes was quite a good idea. I’ve had a couple of emails since then asking me to expand on the idea because “it’s wrong” – I will follow that one up as soon as I can, but in the meantime here’s another angle for connecting old technology with new technology:
It is a feature of in-memory column (more...)
I was aware that up to Oracle 11g, a PL/SQL program wasn’t allowed use an associative array in a SQL statement. This is what happens when I try to do it.
SQL> drop table test_array purge;
SQL> create table test_array as
2 select level num_col from dual
3 connect by level <= 10;
SQL> select * from test_array;
On the 22nd of july, patchset 188.8.131.52 for Oracle 12c database was made generally available for Linux x86-64 and Solaris.
This patchset includes the eagerly awaited In-memory option which promises an application transparent performance boost by using column-format data storage in memory.
Database In – Memory uses an In-Memory column store (IM column store), which is a new component of the Oracle Database System Global Area (SGA), called the In-Memory Area. Data (more...)
There seems to me to be a relatively simple choice.
Either you except that the Oracle Optimizer has a wealth of complicated strategies and, in this complex effort to get the best executions it can, will inevitably either get it wrong sometimes (or take some extra executions to realise it’s wrong).
Or you stick your head in the sand and raise a bug for every unexpected poor execution or plan flip.
But let’s say that (more...)