Monday Dec 08, 2014

Video: Best Practices for Application Performance, Scalability, and Availability

Nancy Ikeda nails it in a great Oracle OpenWorld recording of her Best Practices for Application Performance, Scalability, and Availability session now viewable on the Oracle Call Interface page

The session covered:

Best practice coding samples and techniques show how to resolve connection management, statement execution, and data fetching inefficiencies in applications using APIs such as JDBC, OCI, ODBC, ODP.Net, or higher-level scripting languages. This session shows how the Automatic Workload Repository feature of Oracle Database and Automatic Database Diagnostic Monitor profiling tools help diagnose application design and coding issues. Specific solutions show how to resolve these and other issues to enhance applications for scalability and resilience. Among the solutions discussed are Oracle Database 12c’s new client configuration file. Developers or DBAs can use it to tune and configure applications without modifying code. Examples use JDBC and OCI but are applicable to all APIs.

Nancy is one of Oracle's senior developers working in the call interface group.

Monday Nov 17, 2014

Configuring Python cx_Oracle and mod_wsgi on Oracle Linux

The Web Server Gateway Interface (WSGI) is a standardized interface between web servers and Python web frameworks or applications. Many frameworks including Django support WSGI.

This post is a brief how-to about configuring Apache's mod_wsgi with Python's cx_Oracle driver for Oracle Database. The steps are for Oracle Linux.

  1. Download Instant Client Basic & SDK ZIP files from OTN. For cx_Oracle 5.1, use the ZIPs, not the RPMs.

  2. As root, unzip the files to the same directory, e.g. /opt/oracle/instantclient_12_1:

    mkdir /opt/oracle
    cd /opt/oracle
    unzip /tmp/
    unzip /tmp/
  3. Configure Instant Client:

    cd /opt/oracle/instantclient_12_1
    ln -s
  4. Install the pip package management tool for Python by following and downloading Then run:

  5. Install cx_Oracle:

    export LD_RUN_PATH=/opt/oracle/instantclient_12_1
    export ORACLE_HOME=/opt/oracle/instantclient_12_1
    pip install cx_Oracle

    The key here is the use of LD_RUN_PATH. This obviates the need to later set LD_LIBRARY_PATH or configure ldconfig for cx_Oracle to find the Instant Client libraries. There is a cx_Oracle-specific variable FORCE_RPATH which has the same effect.

    Note the cx_Oracle installer overloads the meaning of ORACLE_HOME. This variable is not normally used with Instant Client.

    Neither ORACLE_HOME or LD_RUN_PATH need to be set at runtime.

    If you don't use LD_RUN_PATH or FORCE_RPATH during installation, you will need to make LD_LIBRARY_PATH available to the Apache process or use ldconfig to add Instant Client to the system wide library search path.

    Configuring ldconfig is an effective and commonly used solution. However it has a potential problem that if multiple Oracle products exist, with possibly differing versions of Oracle libraries on the same machine, then there might be library clashes. If you wish to use it, create a file /etc/ containing:


    Then update the linker cache by running:


    Alternatively set LD_LIBRARY_PATH in Apache's environment file, /etc/sysconfig/httpd. In Oracle Linux 6 use:

    export LD_LIBRARY_PATH=/opt/oracle/instantclient_12_1

    In Oracle Linux 7 use:


    In Oracle Linux 7, don't reference variables on the right-hand side of the equals sign since they won't be expanded.

    [The Apache environment configuration file location varies between Linux distributions. On OpenSUSE see /etc/sysconfig/apache2. On Debian-based distributions look at /etc/apache2/envvars].

  6. Set any other Oracle environment variables in the Apache environment configuration file /etc/sysconfig/httpd. For example:


    (Prefix any variable setting with export in Oracle Linux 6)

  7. Install mod_wsgi:

    yum install mod_wsgi
  8. Add this line to /etc/httpd/conf/httpd.conf:

    WSGIScriptAlias /wsgi_test /var/www/html/
  9. On Oracle Linux 6, start the web server with:

    service httpd start

    On Oracle Linux 7 use:

    systemctl start httpd.service
  10. Create a test file /var/www/html/ that connects to your database:

    #-*- coding: utf-8 -*-
    def query():
        import cx_Oracle
        db = cx_Oracle.connect("hr", "welcome", "localhost/orcl")
        cursor = db.cursor()
        cursor.execute("select city from locations where location_id = 2200")
        return cursor.fetchone()[0]
    def wsgi_test(environ, start_response):
        output = query()
        status = '200 OK'
        headers = [('Content-type', 'text/plain'),
    	       ('Content-Length', str(len(output)))]
        start_response(status, headers)
        yield output
    application = wsgi_test
  11. Load http://localhost/wsgi_test in a browser. The city of the queried location id will be displayed.

That's it. Let me know how it works for you.

Information on cx_Oracle can be found here.

Information on Oracle Linux can be found here.

Information on Oracle Database can be found here.

Wednesday Oct 29, 2014

"PL/SQL: The Scripting Language Liberator" - video recording now available

Oracle University has released a video from Oracle OpenWorld of a great session by Steven Feuerstein and myself. We walked through a PHP application, showed some application tuning techniques for Oracle Database, and then looked at improving the use of Oracle Database features to aid performance and scalability, and also easily add features to the application.

The official blurb was:

PL/SQL: The Scripting Language Liberator: While scripting languages go in and out of favor, Oracle Database and PL/SQL persist, managing data and implementing business logic. This session walks through a web application to show how PL/SQL can be integrated for better logic encapsulation and performance; how Oracle's supplied packages can be used to enhance application functionality and reduce application complexity; and how to efficiently use scripting language connection and statement handling features to get better performance and scalability. Techniques shown in this session are applicable to mobile, web, or midtier applications written in languages such as JavaScript, Python, PHP, Perl, or Ruby on Rails. Using the right tool for the right job can be liberating.

The video is free for everyone. Lots of the other good content in the Oracle Learning Streams is available via subscription, if you're interested.

How to Get the Most out of a Technology Conference (Podcast)

We did good in this recent podcast How to Get the Most out of a Technology Conference (which is cleverly disguised as a video). It has everything the inexperienced conference-goer needs to know. I'm pleased to have been able to give a shout out to PHPWomen! Despite the official blurb, the content applies to all technology conferences and there is very little that is specific to Oracle.

Friday Sep 26, 2014

Oracle OpenWorld is Upon Us! Application Developers Unite!

It's a super, extra, enormously busy time of the year at Oracle because our big Oracle OpenWorld Conference is next week. We have all been working on new products and new presentations.

I have a full mix of events, meetings, presentations and booth duty. If you're at the conference drop by to say Hi. I'll be at the Application Development booth (Left - SLD-163) in Moscone South on Monday morning, Tuesday lunchtime and Wednesday morning (plus other odd times).

Also lookout for me onstage with Tom Kyte on Monday and with Steven Feuerstein on Wednesday.

The session details, and other sessions you might find interesting are listed on my Focus On Application Development page.

If you are a developer, I recommend coming to the Programming and Scripting "Meet the Expert" session at 6pm Tuesday evening (Moscone South - 307). I cannot stress enough how valuable it is to have a dialog and relationship with the developers who create the software and APIs you use.

Tuesday Aug 19, 2014

Routing PHP memcached calls to Oracle Coherence

A new post Getting Started with the Coherence Memcached Adaptor from David Felcey shows how PHP memcached calls can automatically be routed to store data in Oracle Coherence 12c. This is possible now Coherence 12.1.3 supports Memcached clients using the Binary Memcached protocol. David's post shows how the Coherence Memcached adaptor can be configured as a proxy service that runs in the Coherence cluster. There's nothing particular to configure in the PHP application, except to enable memcached.use_sasl = 1

So what is Coherence? It is an "in-memory data grid solution", with a number of advanced features. You can read more in the Oracle Coherence 12C Data Sheet.

Thursday Jul 31, 2014

New Oracle Technology Network PHP Forum URL

The Oracle Technology Network (which promotes the development community) is upgrading its software platform and reorganizing some content. The PHP Oracle forum is now at The top level "PHP Developer Center" is at I notice my old bookmarks for the Developer Center redirect to its current location, but this doesn't seem true of some very old URLs for the forum.

Thursday Apr 24, 2014

Installing PHP on Oracle HTTP Server 12c

OTN have posted an updated guide for installing PHP on Oracle HTTP Server. Check it out!

Using PHP-FPM is a great way to integrate with Oracle Fusion Middleware.

Friday Mar 14, 2014

Performance improvement for OCI_RETURN_LOBS in PHP OCI8 2.0.8

Reducing "round trips" to the database server is important for performance and ultimately for system scalability. A server round-trip is defined as the trip from PHP to the database server and back to PHP.

Reducing round trips makes everything more efficient: PHP is faster, there is less network overhead, the database doesn't have to do a context switch or do any processing for you. Applications have some control over round trips, for example by effectively using prefetching or by using an appropriate execute mode to minimize unneccessary rollbacks at the end of a script.

The bug filer of Bug 66875 noticed that PHP OCI8's implementation itself could reduce round trips if a particular LOB column meta data value was cached for the duration of a query instead of being re-requested for each row of the query result set.

So, now with OCI8 2.0.8, you should see a performance increase if you are doing multi-row queries involving LOB columns returned as OCI_RETURN_LOBS:

$s = oci_parse($c, "select mylobcol from mylobtab");
while (($row = oci_fetch_array($s, OCI_ASSOC+OCI_RETURN_LOBS)) !== false) {
    echo $row['MYLOBCOL'], "\n";

The bug filer tested the patch and added his performance improvement benchmark results to the bug report. The benefit in your environment will vary greatly with the network setup, schema, and how many LOB columns are queried. Test it out and let me know how the new version helps you.

There is no immediate change for LOBs fetched with OCI-Lob::read() and OCI-Lob::load(). This would require a more complex patch than I want to apply at this time. Queries that don't use LOBs are not affected in any way by the patch.

OCI8 2.0 is included in the forthcoming PHP 5.6 code base. For PHP 5.2 to PHP 5.5 you can install it from PECL. PHP 5.5 RPMs with PHP OCI8 2.0.8 are available from

Finally, if your LOB queries return multiple rows, you might also like this tip to reduce PHP memory usage.

Monday Mar 03, 2014

The Oracle Database Access Group is hiring

Over the years I've worked very closely with the Oracle Database Access Group and have a lot of respect for them. I'm happy to share that they are hiring C developers.

To apply, go to and enter the code IRC2401606 or IRC2403582 (depending where you want to work) in the Keyword search box.

Here is an excerpt from the job posting:

The Database Access group at Oracle is responsible for providing functionally comprehensive, reliable, high performance, secure and highly available access to the Oracle Database from various client drivers, including proprietary, standards-based and open-source drivers. The group works on the high level drivers, the Oracle Call Interface (OCI) layer, the Oracle wire protocol (TTC) and highly scalable server side protocol handlers that together connect an application written in any language securely to the Oracle Database Server to provide full featured access to the Oracle Database.

Some of the listed requirements are:

  • Strong C programming experience.

  • Knowledge and experience with latest application development technologies including open source and web technologies (e.g. PHP, Ruby, Python, Node.js, HTML5, JavaScript)

I believe it when they also say "Work is non-routine and very complex, involving the application of advanced technical/business skills in area of specialization". Check out the postings for all the details. I look forward to working with you.

Addendum: IRC2401606 is also available.

Tuesday Feb 11, 2014

Support for binding Oracle PL/SQL BOOLEAN introduced in PHP OCI8 2.0.7

I've released PHP OCI8 2.0.7 which has oci_bind_by_name() support for binding PL/SQL's BOOLEAN type to PHP's boolean. The feature is available when PHP OCI8 2.0.7 is linked-with and connects-to Oracle Database 12c. (The necessary Oracle C library support for binding BOOLEAN was introduced in 12c).

Following the existing PHP OCI8 convention, there are two new constants usable with oci_bind_by_name(): SQLT_BOL and OCI_B_BOL. They have identical values. The former mirrors the underlying Oracle library constant's name (yes, it only has one "O"). The latter follows the PHP OCI8 style of having OCI_B_-prefixed names for bind constants. Note the constants can't be used for array binding with oci_bind_array_by_name().

An example usng the new PHP OCI8 2.0.7 feature is:


  Precreate this PL/SQL function:
    create or replace function is_valid(p in number) return boolean as
      if (p < 10) then
        return true;
        return false;
      end if;


$c = oci_connect('hr', 'welcome', 'localhost/pdborcl');

$sql = "begin :r := is_valid(40); end;";
$s = oci_parse($c, $sql);
oci_bind_by_name($s, ':r', $r, -1, SQLT_BOL);  // no need to give length
var_dump($r);                                  // Outputs: bool(false)


Prior to OCI8 2.0.7 you had to write a wrapper PL/SQL block that mapped the PL/SQL true or false values to 1 or 0.

Code without using OCI8 2.0.7:

$sql = "begin if (is_valid(40) = true) then :r := 1; else :r := 0; end if; end;";
$s = oci_parse($c, $sql);
oci_bind_by_name($s, ':r', $r, -1, SQLT_INT);
echo "Result is " . ($r ? "true" : "false") . "\n";  // Outputs: Result is false

The new functionality removes one small pain point and makes your interaction with Oracle Database 12c PL/SQL cleaner and easier.

Tuesday Dec 10, 2013

Tracing PHP with DTrace - Five Minute Lightning Talk is on Youtube

I gave a 5 minute talk on DTrace in PHP at the SF PHP Meetup Lightning Talk session last night. You can watch it here. It starts at the 14:10 mark.

Tuesday Dec 03, 2013

DTrace and Perl from @GregoryGuillou

Grégory Guillou (@GregoryGuillou) has a post on using DTrace with Perl: Custom DTrace Probes for Perl on Oracle Linux 6. He uses libusdt developed by Chris Andrews (@chrisandrews). Check it out!

Monday Dec 02, 2013

PHP Examples in New "Oracle Linux 6 DTrace Tutorial"

My colleague, Gavin Bowe, has released a new Oracle Linux 6 DTrace Tutorial. It is available in HTML, PDF and ePub from

Chapter 3 on "Tracing User-Space Applications" has some PHP examples.

Tuesday Nov 05, 2013

Tracing Silex from PHP to the OS with DTrace

In this blog post I show the full stack tracing of Brendan Gregg's php_syscolors.d script in the DTrace Toolkit. The Toolkit contains a dozen very useful PHP DTrace scripts and many more scripts for other languages and the OS.

For this example, I'll trace the PHP micro framework Silex, which was the topic of the second of two talks by Dustin Whittle at a recent SF PHP Meetup. His slides are at Silex: From Micro to Full Stack.

Installing DTrace and PHP

The php_syscolors.d script uses some static PHP probes and some kernel probes. For Oracle Linux I discussed installing DTrace and PHP in DTrace PHP Using Oracle Linux 'playground' Pre-Built Packages. On other platforms with DTrace support, follow your standard procedures to enable DTrace and load the correct providers. The sdt and systrace providers are required in addition to fasttrap.

On Oracle Linux, I loaded the DTrace modules like:

# modprobe fasttrap
# modprobe sdt
# modprobe systrace
# chmod 666 /dev/dtrace/helper

Installing the DTrace Toolkit

I download DTraceToolkit-0.99.tar.gz and extracted it:

$ tar -zxf DTraceToolkit-0.99.tar.gz

The PHP scripts are in the Php directory and examples in the Examples directory.

Installing Silex

I downloaded the "fat" Silex .tgz file from the download page and extracted it:

$ tar -zxf silex_fat.tgz

I changed the demonstration silex/web/index.php so I could use the PHP development web server:


// web/index.php

$filename = __DIR__.preg_replace('#(\?.*)$#', '', $_SERVER['REQUEST_URI']);
if (php_sapi_name() === 'cli-server' && is_file($filename)) {
    return false;

require_once __DIR__.'/../vendor/autoload.php';

$app = new Silex\Application();

//$app['debug'] = true;

$app->get('/hello', function() {
        return 'Hello!';



Running DTrace

The php_syscolors.d script uses the -Z option to dtrace, so it can be started before PHP, i.e. when there are zero of the requested probes available to be traced. I ran DTrace like:

# cd DTraceToolkit-0.99/Php
# ./php_syscolors.d

Next, I started the PHP developer web server in a second terminal:

$ cd silex
$ php -S localhost:8080 -t web web/index.php

At this point, the web server is idle, waiting for requests. DTrace is idle, waiting for the probes in php_syscolors.d to be fired, at which time the action associated with each probe will run.

I then loaded the demonstration page in a browser:


When the request was fulfilled and the simple output of "Hello" was displayed, I ^C'd php and dtrace in their terminals to stop them.

DTrace output over a thousand lines long had been generated. Here is one snippet from when run() was invoked:

C    PID/TID   DELTA(us)              FILE:LINE TYPE     -- NAME
1   4765/4765         21   Application.php:487  func     -> run
1   4765/4765         29   ClassLoader.php:182  func       -> loadClass
1   4765/4765         17   ClassLoader.php:198  func         -> findFile
1   4765/4765         31                 ":-    syscall        -> access
1   4765/4765         26                 ":-    syscall        <- access
1   4765/4765         16   ClassLoader.php:198  func         <- findFile
1   4765/4765         25                 ":-    syscall      -> newlstat
1   4765/4765         15                 ":-    syscall      <- newlstat
1   4765/4765         13                 ":-    syscall      -> newlstat
1   4765/4765         13                 ":-    syscall      <- newlstat
1   4765/4765         22                 ":-    syscall      -> newlstat
1   4765/4765         14                 ":-    syscall      <- newlstat
1   4765/4765         15                 ":-    syscall      -> newlstat
1   4765/4765         60                 ":-    syscall      <- newlstat
1   4765/4765         13                 ":-    syscall      -> newlstat
1   4765/4765         13                 ":-    syscall      <- newlstat
1   4765/4765         20                 ":-    syscall      -> open
1   4765/4765         16                 ":-    syscall      <- open
1   4765/4765         26                 ":-    syscall      -> newfstat
1   4765/4765         12                 ":-    syscall      <- newfstat
1   4765/4765         17                 ":-    syscall      -> newfstat
1   4765/4765         12                 ":-    syscall      <- newfstat
1   4765/4765         12                 ":-    syscall      -> newfstat
1   4765/4765         12                 ":-    syscall      <- newfstat
1   4765/4765         20                 ":-    syscall      -> mmap
1   4765/4765         14                 ":-    syscall      <- mmap
1   4765/4765       3201                 ":-    syscall      -> mmap
1   4765/4765         27                 ":-    syscall      <- mmap
1   4765/4765       1233                 ":-    syscall      -> munmap
1   4765/4765         53                 ":-    syscall      <- munmap
1   4765/4765         15                 ":-    syscall      -> close
1   4765/4765         13                 ":-    syscall      <- close
1   4765/4765         34       Request.php:32   func         -> main
1   4765/4765         22       Request.php:32   func         <- main
1   4765/4765         31   ClassLoader.php:182  func       <- loadClass
1   4765/4765         33       Request.php:249  func       -> createFromGlobals
1   4765/4765         29       Request.php:198  func         -> __construct
1   4765/4765         24       Request.php:218  func           -> initialize
1   4765/4765         26   ClassLoader.php:182  func             -> loadClass
1   4765/4765         89   ClassLoader.php:198  func               -> findFile
1   4765/4765         43                 ":-    syscall              -> access

The output shows PHP functions being called and returning (and where they are located) and which system calls the PHP functions in turn invoked. The time each line took from the previous one is displayed in the third column.

The first column is the CPU number. In this example, the process was always on CPU 1 so the output is naturally ordered without requiring post-processing, or the D script requiring to be modified to display a time stamp.

On a terminal, the output of php_syscolors.d is color-coded according to whether each function is a PHP or system one, hence the file name.


With one tool, I was able to trace the interaction of a user application with the operating system. I was able to do this to an application running "live" in a web context.

The DTrace Toolkit provides a very handy repository of DTrace information. Even though the PHP scripts were created in the time frame of the original PHP DTrace PECL extension, which only had PHP function entry and return probes, the scripts provide core examples for custom investigation and resolution scripts. You can easily adapt the ideas and create scripts using the other PHP static probes, which are listed in the PHP Manual.

Because DTrace is "always on", you can take advantage of it to resolve development questions or fix production situations.


Tourists looking out over an Opal mine
I'm a Product Manager in Server Technologies, working on scripting languages and developer-access.
Links: OTN Node.js Developer Center
OTN PHP Developer Center
Book: Free PHP Oracle book

Blaine Carter
Dan McGhan


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