Archive for the ‘Oracle’ Category

Oracle Event Processing – Pattern Matching Example 2

In previous post I showed off one of the pattern matching feature of Oracle Event Processing and in this section I am gonna show another example of it.

There are many built-in functions which can be used in CQL. I think one of the most important these functions is the prev function. Prev function facilitates accessing the previous elements in the same stream/partition easily.

Consider this scenario, we have stock values as below and I would like to find out the pattern; firstly average value of previous 3 elements should be greater than 10 and the last value greater than the last value of the previous condition.

If we want to write to CQL code of our requirements it would look like:

CQL Example

With numbers lets try to understand how the pattern can be matched ( left side: incoming events; right side: expression about pattern matching):

Events and patterns


Run the application:


As shown in above, after the 13 and 33 pattern has been matched and output was produced.




Oracle Event Processing – Pattern Matching Example

Event processing technologies became famous in recent years. Companies realizes that they need to take real time action in order to satisfy customer requirements or handle several component issues happened in some internal system or advertising etc.

Oracle Event processing has several processing methods in order to process incoming real time data. In this blog post I will show off one of the pattern matching operations.

Consider, you desire to find out which stock firstly increases then decreases three times and increases again. For example;


In the above numbers we will find out the pattern which starts with 6.48 and ends with 6.47. Because it firstly incremented from 6.48 to 6.49 and then decreased three times ( 6.48,6.47,6.46 ) and then increased from 6.46 to 6.47 again.

I am using the Oracle Event Processing for Windows 64bit and Cygwin as windows terminal.

I changed a little bit the HelloWorld default cep application. The most crucial part is the CQL Processor part, how should I implement the CQL in order to find out the patterns?

OCEP Cql Processor Pattern Matching

OCEP Cql Processor Pattern Matching

Let’s look at the clauses in briefly.

StockProcessor is the name of the cql processor.
PARTITION BY shortName: Partition incoming data by shortName ( CQL Engines calculates each partition individually. For example, ORCL, IBM, GOOG prices are computed individually. )
MEASURES : Which values, fields will be in the output
PATTERN : Order of conditions ( Look at regular expression for more details )
DEFINE : Defining the conditions, “A as” means the define condition A.

Run the application and type the stock name and prices as in below:

OCEP Cql Processor Pattern Matching Demo

OCEP Cql Processor Pattern Matching Demo

Just after pattern is matched the output event is produced and in this example I just printed the name and last price value of the stock.

I didn’t specify any performance measurements but if the number of distinct stocks are increased performance will be our first concern. However, I would like to share some performance results in a another blog post later.

The Book: Getting Started with Oracle Event Processing 11g

Packt Publishing is the UK based tech book publishers which will publish an expected book in a few days.

Besides, this book is the my first book which I am the one of the reviewer:

Getting Started with Oracle Event Processing 11g

Getting Started with Oracle Event Processing 11g

The one of the authors is the Robin J. Smith who is a great and much more experienced IT man who I met in the Istanbul at a lunch. The people who are looking for a book which tells the concepts of the Event Processing with really good designed examples and includes much more detail about the Oracle Event Processing 11g product; this book is definitely for you.

Using Variable Based Hints in an ODI Knowledge Module

February 15, 2013 1 comment

In an ODI interface we know that a knowledge module should be chosen. This knowledge module lines up the steps which are executed in order. And also we can add “Options” and “Checks” to make a knowledge module more generic. For more information click here to view documentation . In the knowledge module steps we have been using Oracle sql statements and and also sql hints has been used. How can we implement the hints in the sql statements which are used in the knowledge module?

Since many interfaces use the same knowledge module, it should be generic.

If we add hints directly into the knowledge module as in the below we should prepare a new knowledge module for each interface and as you’ve predicted this method a little bit creepy.


Instead, we can add KM options to that knowledge module as my mentor have explained in his blog, .

That method is really useful when you need to use SQL hints in your sql statements. But we thought that we can enhance a little bit more to make this method more practical. Consider that if we want to change the hint option value such as increase the parallel degree of  select statement, we should change the option in the interface. Even if your production environment has just execution repository, you could not do that.

Gurcan and me  thought about it and developed a new method to make the parallelism more generic. In a database table we will store the hints of each interface. Consider a knowledge module, its name is “INCREMENTAL UPDATE” and it has 10 steps, totally 15 dml statements. Each dml statements contains hint clauses.

This kind of database table like this:


For example the TEST_INTERFACE interface uses the “INCREMENTAL UPDATE” knowledge module and this knowledge module has 9 dml statements which can contain hint clause.

The problem is how to access this database table and how to use hint clauses in knowledge module steps.

We know how to access the database in a knowledge module step but how to assign hint clauses which are in the database to java or jython variables.


Add a step into knowledge module to get the hint clauses from the database. Name the step as “Get Hiints”.



Select “Command on Source” tab and in the text area we should write the sql statement to get hint clauses.:


The sql statement which I wrote seem a little bit complex  but it is not. The point is you should get just ONE ROW with these sql statement however there may be multiple columns it is worthless. In fact, the sql query should return like this row:


The other important part is we use the


method to use interface’s name, we need to this clause because just before when an interface starts to run hints read from the database table by using interface name.


After you’ve completed the query in the source tab, select the target tab and configure the java variables as shown in the below:


We define 9 java variables and each of them contains a hint clause, they are read from the database and assign to the java variables. Pay attention here,

String insertFlow_insertHint=”#HINT_1”;

It means that read the “HINT_1” field (column) of the sql query and assign it to the “insertFlow_insertHint” java variable. Since there is a sql column to java variable assignation, the sql query should not return more than one row.


Now, we have the hint clauses in the java variables the last point is how to use java bean variables in a sql statements.


In a knowledge module step you can use the java variables as shown in the above.

In this blog post I tried to tell how to use variable based sql hints in the ODI knowledge modules. Let’s discuss the things which can be more generic!

Coherence Index Performance

In a traditional database we use the index to access filtered data as quickly as possible. In the coherence, indexes are used for same purpose as well, fast access to filtered data. If you wish to retrieve all the items in the cache, likely index are not appropriate for you same as when you use database index. For example, when using the Oracle database and if you use a filter to retrieve data but its selectivity is close to 1, Oracle cost based optimizer can choose to not use the indexes because it’s not necessary since each index operations requires one more I/O. Likewise, in coherence when you wish the get data you should decide correctly whether use it or not.

Anyway, in this blog post I will carry out basic filter operations with and without index.

NamedCache cache = CacheFactory.getCache("persons");
PersonGenerator pg = new PersonGenerator();

System.out.println("Cache loaded:"+cache.size()+" elements.");

Filter filter = 
	new OrFilter(
		new AndFilter(
			new EqualsFilter("getFirstName", "Hugo"),
			new GreaterFilter("getAge", 50)
		new AndFilter(
			new EqualsFilter("getFirstName","William"),
			new LessFilter("getAge",50)

Firstly, I connected to the cluster and cache, after that 2 millions of people object is generated, they all put into the cache. Then, filter is created, pay a little bit more attention to here, uppermost the orfilter was used and two and filters was used in the filter. If we convert this filter clause to an sql query it would be :

select * from people where ( firstName="Hugo" and age>50 ) or ( ( firstName="William" and age<50 )

As it is seen here, we are just looking for the firstname and age fields for filtering. If these fields can be used in indexes we could improve the query performance.

To get filtered data we use the entrySet method by passing the Filter object as argument like this:

Set filteredData;
filteredData = cache.entrySet(filter);
System.out.println("Without Index:" + Timer.getDurationMSec());

It prints:

Without Index:12091

Time is milliseconds based.

As you know we don’t use index so far, it is the time to add one:

cache.addIndex(new ReflectionExtractor("getFirstName"), false, null);
	filteredData = cache.entrySet(filter);
System.out.println("With Index:" + Timer.getDurationMSec());

AddIndex method has been used to add index and first parameter of this method is the field’s get method which will be indexed. Second parameter gets a boolean variable and it determines the whether index is sorted or not. Sorted index is useful for range queries like ” age > 20 ” . While creating this index we did not use sorted index because we just looking for equalities, but we’ll use sorted index in the next one.
This code part prints:

With Index:5300

As you see, with one index, entrySet method double times faster than the previous one, without index.
We know that our filter uses two fields, one of them is the firstname which was just before indexed and the other one is the age. We can use age field as well in the index:

cache.addIndex(new ReflectionExtractor("getAge"), false, null);
	filteredData = cache.entrySet(filter);
System.out.println("With Two Indexes:" + Timer.getDurationMSec());

It prints:

With Two Indexes:1017

In order to get the filtered data set faster we can use the indexed object fields which are used in the filter. If we index the fields which are not used in the filter we won’t get any performance improvement.

cache.removeIndex(new ReflectionExtractor("getFirstName"));
cache.removeIndex(new ReflectionExtractor("getAge"));

cache.addIndex(new ReflectionExtractor("getCitizenNumber"), true, null);
filteredData = cache.entrySet(filter);
System.out.println("With Index BUT Not in the filter:" + Timer.getDurationMSec());

It prints:

With Index BUT Not in the filter:

11391 milliseconds is almost same duration of without index.

How a member can use the existing cache in Coherence

August 23, 2012 1 comment

In the previous post, I’ve explained how a member can join the existing cluster. Before read this post you should understand what was going on there.

At the final in previous post the new member joined the cluster. In this post I’ll explain how a member can use the existing cache ( customers cache which was created by the Eclipse project in this post )

Let’s go on from previous post.
Cluster Join
At the bottom of this screenshot you see that there is a prompt. To use existing cache ( this is the cache it has already created and it’s name is customers ) we type :

Map(?): cache customers

And it gives this output:

As you see the coherence was reading default cache configuration file instead of our cache config file. To force coherence to read our cache configuration file we should edit the JAVA_OPTS parameter in the file ( it was created in previous post ) and add this clause by changing the real path :

-Dtangosol.coherence.cacheconfig=/home/oracle/labs/Coh_labs/workspace/CohExam_AFSungur/src/config/coherence-cache-config.xml -Dtangosol.pof.config=/home/oracle/labs/Coh_labs/workspace/CohExam_AFSungur/src/config/pof-config.xml

These xml files are under the src/config folder of the Eclipse project which has already been created.
And also you should change the classpath parameters because in the pof-config.xml file there is a class that should be specified in the classpath to use pof configuration.
To edit classpath parameters, edit the file and go to the line which starts with JAVA_EXEC and change the -cp parameter as :

-cp "-classpath /home/oracle/labs/Coh_labs/workspace/CohExam_AFSungur/src/config:/labs/wls1211/coherence_3.7/lib/coherence.jar:/home/oracle/labs/Coh_labs/workspace/CohExam_AFSungur/bin" 

After editing file save this file as file. The file is here:

Run this sh file.
Then type “cache customers” again in the prompt then you’ll see this output:

As shown in above loaded cache configuration file and pof configuration file is as we wanted. When querying the size of the cache it returns the correct answer:

Map (customers): size

Map (customers): 

Joining the Existing Cluster in Coherence

August 21, 2012 3 comments

In previous post I had tried to explain some of the output parameters of Coherence. In this post I will explain how a member can join the existing cluster by setting some parameters.

Before this post you should completed this post:
Running a Coherence Application in Eclipse
We’ve already run this example within Eclipse. Basically it creates a cluster and a cache then put a custom object into the cache. And because of code is over in Coherence Cache automatically closed. To prevent closing automatically we’ll edit the and add the below code to control the application flow.

String dummy;
Scanner user_input = new Scanner( );
dummy = );

And the changed version of is now here:

package com.afsungur.coherence.test;

import java.util.Scanner;

import com.afsungur.coherence.objects.Customer;

public class CustomerTest1 {

        public static void main(String args[])
        Customer cust = new Customer("Ahmet Fuat", "Sungur", "Bahcelievler/Istanbul", "", "5321231231", 34111);
        NamedCache cache = CacheFactory.getCache("customers");
        cache.put(1, cust) ;
        System.out.println("Cache Size:"+cache.size());

        String dummy;
        Scanner user_input = new Scanner( );
        dummy = );



After editing you can run the application inside Eclipse and then you see that application will wait for some input to terminate the cache server. But before terminating we may allow another member to join the cluster.

By the way you can check which parameters were used to start cluster inside the Eclipse as shown in below :

[oracle@localhost bin]$ ps -ef | grep coherence
oracle    6835  2873  8 13:18 ?        00:00:02 /labs/wls1211/jdk160_29/bin/java -Dtangosol.coherence.cacheconfig=src/config/coherence-cache-config.xml -Dtangosol.coherence.cluster=MyFirstCluster -Dtangosol.pof.config=/home/oracle/labs/Coh_labs/workspace/CohExam_AFSungur/src/config/pof-config.xml -Dtangosol.coherence.clusterport=7252 -Dfile.encoding=UTF-8 -classpath /home/oracle/labs/Coh_labs/workspace/CohExam_AFSungur/src/config:/labs/wls1211/coherence_3.7/lib/coherence.jar:/home/oracle/labs/Coh_labs/workspace/CohExam_AFSungur/bin com.afsungur.coherence.test.CustomerTest1
oracle    6874  5387  0 13:19 pts/1    00:00:00 grep coherence
[oracle@localhost bin]$ 

And so, how we can add a member to cluster? We know that there is a cluster which serves from 7252 port and also we now the cluster name ( MyFirstCluster ) and so on. We can check this parameters from Run->Run Configurations->Coherence(Main Tab)->Other(Sub Tab).
And also you can check as shown in above by using “ps” linux command.

Under the bin folder of coherence main folder ( something like coherence3.7/bin ), there are some sh files. and can be used to join cluster. provides an interactive environment to query the cache for putting, getting, listing or something else. Therefore, we use to join cluster.

Just before running the file we edit file and add below arguments to the line which starts with “JAVA_OPTS=” and then save as the file .

-Dtangosol.coherence.cluster=MyFirstCluster -Dtangosol.coherence.clusterport=7252

Then, start the and the analyse the output:
Cluster Join

Most part of output is similar to single member cluster. But there are a few differences.
First of all, at the top of output you see that new member are using the default operational configuration file which is inside the jar file.
And the middle of the output at the MasterMemberSet section you can see that currently how many members are there in the cluster, what is the current member id (ThisMember part), oldest member id and so on.
At the bottom of page you can see the interactive command line and “Map (?):” is written at the left side. Type “help” and then you can see all available commands.

In this post I’ve explained how a member join the existing cluster. In next post I’ll explain how just joined member can use the existing cache.