On CSS/jQuery Selector Performance

My post describing the use of a simple selector identifying page spinners was originally going to be about performance, then I learned something I found very interesting.

I likened what I learned to Tom Kyte's essay (Asktom->Resources->Presentations->FalseKnowledge.htm) on Correlation vs Causation. The essence was that things change over time, and we can't always trust authorities on the topic, and we must always test in our own environments. This aligns with skepticism in general, and (more...)

Improving PL/SQL performance in APEX

One of the simplest tuning techniques to encapsulate PL/SQL used in APEX within packages, minimising the size of anonymous blocks. This applies to any PL/SQL within the page, including computations, processes, plugins, dynamic actions, validations, shortcuts and dynamic PL/SQL regions.

This change can make a big impact in the execution time of PL/SQL as it's processed at compile time instead of interpreted at runtime.

Plug-ins can be wonderful black boxes and consumers may not care (more...)

Analyzing Performance

People ask me quite a lot about how I analyze performance issues. While I have some guidelines, there is no complete answer to this question. The actions I take depend on the situation, and there are many many different scenarios when talking about performance problems. In this post I’ll describe an analysis I did about […]

Monitoring ADF 12c Client Request Time with Click History

You must be excited to read this post, I will describe one very useful feature, available in ADF 12c. This feature - Click History. You can follow steps described by Duncan Mills, to enable and read click history data in server log. There is one more option available - we can read click history data from ADF request (captured by filter class) and log it in custom way (for later analysis). Click history gives such (more...)

Oracle Management Cloud – IT Analytics

In this post I will give you a first glance of a demo environment of…

Oracle Management Cloud – The “Application Performance Monitoring” service

A while ago I created a first post about the Oracle Management Cloud ( #OMC…

New OTN Article – OBIEE Performance Analytics : Analysing the Impact of Suboptimal Design

I’m pleased to have recently had my first article published on the Oracle Technology Network (OTN). You can read it in its full splendour and glory (!) over there, but I thought I’d give a bit of background to it here and the tools demonstrated within.

OBIEE Performance Analytics Dashboards

One of the things that we frequently help our clients with is reviewing and optimising the performance of their OBIEE systems. As part (more...)

How To Be More Productive with JDeveloper 12c Application Redeployment

When you work on larger JDeveloper/ADF 12c project, most likely you will experience issues with application redeployment (rerun). These two issues will be encountered:

1. It doesnt work anymore (it worked on 11g) to simply rerun application (applies for 12.1.3 and 12.2.1), without stopping it and then running again. In most of the cases if you try to rerun application, some strange errors are returned or changes are not visible at (more...)

OFM Forum Session Slides – Oracle JET and WebSocket

I would like to post slides from my session on Oracle Fusion Middleware Forum - Oracle JET and WebSocket. This session was done today.

Slides are available on slideshare:

Sample application used for the demo, can be downloaded from here (it consists of three parts - WebSocker server implementation, ADF BC tester application to generate continuos DB updates and JET application) - Oracle JET Live List with WebSocket.

ADF application with live data DVT component (more...)


Can you spot anything that might appear to be a little surprising about this (continuous) extract from a trace file ? The example is from, but 11g and 12c could produce similar results (or direct path read equivalents):

PARSING IN CURSOR #3 len=23 dep=0 uid=30 oct=3 lid=30 tim=112607775392 hv=4235652837 ad='2f647320'
select count(*) from t1
PARSE #3:c=0,e=53,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=1,tim=112607775385
EXEC #3:c=0,e=99,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=1,tim=112607787370
WAIT #3: nam='SQL*Net message to client' ela= 9 driver id=1111838976 #bytes=1  (more...)

Oracle Cloud – Oracle Management Cloud

Oracle Management Cloud is a new Oracle Cloud offering launched during Oracle Open World 2015,…

OUG_Ireland – Bread, Beer & Playing with the Big Boys

The last banner turned out to be wrong

The last banner turned out to be wrong


Learning, sharing & a small dose of fear – Last week was the OUG Ireland conference 2016. It is the second time I’ve been to the Irish Oracle user group conference and this year it had grown from one day to two days – and that was a great success. The expanded 2-day event, as initially sized, booked up with several weeks still to go. More places (more...)

Oracle JET Live List with WebSocket

I have updated sample - Oracle JET and WebSocket Integration for Live Data, to include live data list. Along with live updates delivered to the chart component, list component displays changed data. I'm displaying five last changes, with new data appearing in the last row:

Watch recorded demo, each 4 seconds new data arrives and chart is updated, along with list records:

JET list component UI structure (data grid) is rendered with a template, (more...)

PerfSheet.js: Oracle AWR Data Visualization in the Browser with JavaScript Pivot Charts

PerfSheet.js is a tool aimed at DBAs and Oracle performance analysts. It provides a simplified interface to extract and visualize AWR time series data in the browser using javascript.

The reason for a tool like PerfSheet.js is to make the analysis of AWR data easier by providing a graphical interactive interface and by automating several repetitive steps of data extraction and chart preparation. Pivot charts provide a flexible and easy to use way to navigate (more...)

Big Data – Tez, MR, Spark Execution Engine : Performance Comparison

| Feb 25, 2016

There is no question that massive data is being generated in greater volumes than ever before. Along with the traditional data set, new data sources as sensors, application logs, IOT devices, and social networks are adding to data growth. Unlike traditional ETL platforms like Informatica, ODI, DataStage that are largely proprietary commercial products, the majority of Big ETL platforms are powered by open source.

With many execution engines, customers are always curious about their usage (more...)


Oracle PARTIAL INDEXES – a new feature in Oracle 12c, initial impression was really good, but the implementation is quite poor. With this feature, you can define INDEXING OFF for a partition so that any index with PARTIAL clause will skip this partition while creating the index. The advantage is you can selectively create indexes on partitions. And for a global index or a global partitioned index, the rows from the INDEXING OFF partitions will (more...)

Oracle JET and WebSocket Integration for Live Data

I was researching how to plugin WebSocket into JET. I would like to share my findings and explain how it works. It is amazing, how scalable and quick it is to send JSON message through WebSocket channel and render it in JET. Luckily WebSocket client is implemented in JavaScript, this integrates perfectly with Oracle JET (also based on JavaScript).

Watch recorded demo, where I'm sending updated data with JSON message through WebSocket. UI chart is (more...)

The Oracle wait interface granularity of measurement

The intention of this blogpost is to show the Oracle wait time granularity and the Oracle database time measurement granularity. One of the reasons for doing this, is the Oracle database switched from using the function gettimeofday() up to version 11.2 to clock_gettime() to measure time.

This switch is understandable, as gettimeofday() is a best guess of the kernel of the wall clock time, while clock_gettime(CLOCK_MONOTONIC,…) is an monotonic increasing timer, which means it (more...)

PL/SQL context switch, part 2

This is the second blogpost on using PL/SQL inside SQL. If you landed on this page and have not read the first part, click this link and read that first. I gotten some reactions on the first article, of which one was: how does this look like with ‘pragma udf’ in the function?

Pragma udf is a way to speed up using PL/SQL functions in (user defined function), starting from version 12. If you want (more...)

Linux Perf Probes for Oracle Tracing

Topic: this post is about Linux perf and uprobes for tracing and profiling Oracle workloads for advanced troubleshooting.


The recent progress and maturity of some of the Linux dynamic tracing tools has raised interest in applying these techniques to Oracle troubleshooting and performance investigations. See Brendan Gregg's web pages for summary and future developments on dynamic traces for Linux. Some recent work on applying these tools and techniques to Oracle can be found (more...)