JDeveloper 12c ADF View Token Performance Improvement

There is known limitation in ADF 11g, related to accessing application in the same session from multiple browser tabs. While working with multiple browser tabs, eventually user is going to consume all view tokens, he will get timeout error once he returns back to the previous browser tab. Unused browser tab is producing timeout, because ADF 11g is sharing the same cache of view tokens for all browser tabs in the same session. This means (more...)

BPEL 11g threads in parallel flow

A lot has been written about the transactions, boundaries, threads etc in the Oracle SOA Suite. Clemens has written this piece years ago which explains the basics.I recently had a ‘disagreement’ with the SOA threadpool when I was using a parallel flow in a synchronous BPEL process.

The requirement was to guard the execution time of this BPEL process to a predefined maximum amount of seconds. The environment is as such that tweaking the (more...)

Getting The Users’ Trust – Part 1

Looking back over some of my truly ancient Rittman Mead blogs (so old in fact that they came with me when I joined the company soon after Rittman Mead was launched), I see recurrent themes on why people “do” BI and what makes for successful implementations. After all, why would an organisation wish to invest serious money in a project if it does not give value either in terms of cost reduction or increasing profitability (more...)

12c HCC Row-Level Locking

In Oracle Database 12c we can find many new and shiny things… So many that we can miss the little good things really easy. I think that this one, is one of them. Previously I made a post “All About HCC“, describing how HCC is working and some of the issues that we can hit […]

Querying trace files

SQL trace file provide the highest level of detail possible about SQL execution. The problem with that information is converting it to a convenient format for further analysis. One very good solution is parsetrc tool by Kyle Hailey written in Perl. It gives high-resolution histograms, I/O transfer rates as a function of time, and other very useful info. Unfortunately, I myself am not a Perl expert, so it’s a bit difficult for me to customize (more...)

Oracle IO wait events: db file sequential read

(the details are investigated and specific to Oracle’s database implementation on Linux x86_64)

Exadata IO: This event is not used with Exadata storage, ‘cell single block physical read’ is used instead.
Parameters:
p1: file#
p2: block#
p3: blocks

Despite p3 listing the number of blocks, I haven’t seen a db file sequential read event that read more than one block ever. Of course this could change in a newer release.

Implementation:
One of the important things (more...)

Oracle Cloud Friendly – Red Samurai ADF Performance Audit

I have deployed our tool for ADF performance monitoring to Oracle Java Cloud service. It runs perfectly on the cloud, monitors slow performance and allows to analyse collected performance data. All data is stored in Oracle Database Cloud.

You can access performance monitoring dashboard using this address. Access will be available for a month or so, until my trial account will expire. You would need to use following login credentials - user: redsam, password (more...)

Complément : Analyse des performances sur du long terme

In-memory Aggregation

The title of this piece is the name given to a new feature in 12.1.0.2, 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...)

Scaling up Cardinality Estimates in 12.1.0.2

Topic: 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 12.1.0.2 provides a new function APPROX_COUNT_DISTINCT implemented with a new-generation algorithm to address this issue by providing (more...)

Review: "WildFly Performance Tuning" by Arnold Johansson and Anders Welén

I've had the pleasure to review another book for Packt. This time it is the performance tuning guide for WildFly. Arnold Johansson and Anders Welén took a deeper look into what it takes to develop and run high performance applications on WildFly and collected a bunch of tips and tricks everybody should know.

Abstract
The hugely successful JBoss Application Server has been updated and is now called WildFly. This cutting edge technology provides a free (more...)

Oracle 12c Database In-Memory option generally available

On the 22nd of july, patchset 12.1.0.2 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...)

Oracle Database 12.1.0.2.0 – Turning OFF the In-Memory Database option

So how to turn it the option off/disabled…As a privileged database user: > Just don’t set the INMEMORY_SIZE parameter to a non zero value…(the default...

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Being Right and Proving It

One of the great things about working in IT is that you can often win an argument simply by being right. Not because of who you are or because you are more eloquent than others, but because the facts support your position. Almost every IT person I have ever met respects facts.

In order to win arguments this way, you of course need some facts to work with. And that’s where too many people fail. (more...)

Oracle Database 12.1.0.2.0 – Native JSON Support (1)

Oracle Database 12.1.0.2 has now native support build-in for handling JSON (Javascript Object Notation) data. Oracle Database supports JSON natively with relational database features, including...

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That’s … Huge!

Recently I’ve noticed the occasional thread in Oracle newsgroups and lists asking about hugepages support in Linux, including ‘best practices’ for hugepages configuration. This information is out on that ‘world-wide web’ in various places; I’d rather put a lot of that information in this article to provide an easier way to get to it. I’ll cover what hugepages are, what they do, what they can’t do and how best to allocate them for your particular (more...)

Exadata storage indexes and DML

Last week I’ve gotten a question on how storage indexes (SI) behave when the table for which the SI is holding data is changed. Based on logical reasoning, it can be two things: the SI is invalidated because the data it’s holding is changed, or the SI is updated to reflect the change. Think about this for yourself, and pick a choice. I would love to hear if you did choose the correct one.

First (more...)

New Version Of XPLAN_ASH Utility

A new version 4.1 of the XPLAN_ASH utility is available for download.

As usual the latest version can be downloaded here.

This version in particular supports now the new 12c "Adaptive" plan feature - previous versions don't cope very well with those if you don't add the "ADAPTIVE" formatting option manually.

Here are the notes from the change log:

- GV$SQL_MONITOR and GV$SQL_PLAN_MONITOR can now be customized in the
settings as table names in (more...)

B-tree and nulls

Today while I was scrolling my “WordPress reader” page I saw a post which reminds me to something I had fun before /and find it useful in many situations/: So if we have an index based on null column followed by not null column we can use it to filter the rows with null value. […]

FIRST_ROWS_n Optimizer Mode – What is Wrong with this Statement?

June 8, 2014 It has been nearly two years since I last wrote a review of an Oracle Database related book, although I have recently written reviews of two Microsoft Exchange Server 2013 books and a handful of security cameras in the last two years.  My copy of the second edition of the “Troubleshooting Oracle […]