Application Diagnosis with Zend Server Tracing

Application Diagnosis with Zend Server Tracing
Kevin Schroeder
Zend Technologies

About me
Kevin Schroeder
Consultant for Zend
Programmer
Sys Admin
Author
Etc.
Me!

"As soon as we started programming, we found to our surprise that it wasn't as easy to get programs right as we had thought. Debugging had to be discovered. I can remember the exact instant when I realized that a large part of my life from then on was going to spent in finding mistakes in my own programs"
- Maurice Wilkes, 1949

Why do we need diagnostic tools?

Let’s see that again in slow motion

The point
NOT to highlight an individual company
Why not?
How many web-based applications look like this when an error occurs?
Answer
All of them
Web requests are intended to be short and quick
If an error occurs, recover, quit and go on to the next request

Debugging the old way
var_dump($var)(I still use this occasionally)
Some obvious problems
What if you forget to remove it?
Are you doing this in a production environment? If you are …
Very limited scope

Debugging the better way – ZS Debugging
You can see what the variable values are at run time and modify them too
Good for development
Not good for production

Monitoring
MUCH better for production systems
You get a lot of really good information to help replay the issue

Monitoring
You are able to debug or profile the event on a remote machine

Events that can be monitored

Instrumentation on the next level
Zend Code Tracing

Code Tracing: Rapid Problem Resolution
Similar in concept to a black box flight recorder - Eliminates the need to reproduce problems in order to find root cause
Activated automatically (through rules) or manually
Records live application execution
Function calls
Arguments and return values
Errors
Duration
Useful in all parts of the software development lifecycle

Practical Code Tracing Functionality
By capturing PHP applications code in real time:
Code Tracing enables to capture problems when they occur.
Code Tracing recorded data eliminate the need to reproduce the steps led up to a failure.
Code Tracing enables to analyze PHP applications execution both in production and in test lab environments, by that, it enables to quickly find the root cause of problems.
14
Insert->Header & Footer

Supported Workflows
Manual workflow:
Used while performing unit tests during development or when running functional tests in QA.
Calling URLs as part of the testing process
Monitoring events workflow
Used when running automated tests and load tests and when running your application in staging or production environments.
Code tracing extends the monitoring rules mechanism by enabling to save trace data when a monitoring event is generated.
Suitable for production in Standby mode

Detailed Runtime Instrumentation
Pinpoint root cause by viewing the sequence of events that led up to an error

Detailed Runtime Instrumentation
Optimize your code by analyzing application performance at the function level

Code Tracing – Monitoring Level Modes
Always on
Collects trace data when monitoring event is kicked off
Collects trace data for manual requests.
Inactive
Collects data only for manual requests.
Standby
Off (turn code tracing extension off)

Code Tracing – Operating Modes
Standby mode
A monitoring event activates code tracing
Trace mode:
On
Standby
Tracing switches back for “Standby” mode
Tracing is activated for X minutes
Time
A monitoring event with an “Activate Trace” action is generated
Collect trace data according to the monitoring set of rules

The basics
Trace a Request

Interpreting the results
Screenshots are boring. Let’s look at live data

Setup
Attaching traces to events
Tracing can be attached to any PHP-specific events

Tracing Events – Standby Mode
Set zend_monitor.event_tracing_mode
Active, Inactive or Standby
Determines integration with tracer mechanism in case of events that require a trace data dump
Create an Event Action – “Enable Tracing” will change

Tracing Process Signals
Tracing can also be initiated upon a fatal signal

Tracing Log
Step 1 – Make sure that you have it set to log
Step 2 – Set the verbosity between 1 and 5
Restart

Example log file
[Tracing Log 08.10.2009 14:14:56 DBG1] 5387 Tracer request startup
[Tracing Log 08.10.2009 14:14:56 DBG3] 5387 Setting dump reason to 0
[Tracing Log 08.10.2009 14:14:56 DBG3] 5387 Dump reason is now 0
[Tracing Log 08.10.2009 14:14:56 DBG1] 5387 Remote address is 127.0.0.1
[Tracing Log 08.10.2009 14:14:56 DBG2] 5387 Allow hostmask is 127.0.0.1/32,10.0.0.0/8,192.168.0.0/16,172.16.0.0/12
[Tracing Log 08.10.2009 14:14:56 DBG2] 5387 Deny hostmask is
[Tracing Log 08.10.2009 14:14:56 DBG1] 5387 Remote access allowed
[Tracing Log 08.10.2009 14:14:56 DBG1] 5387 Request parameter requires dump
[Tracing Log 08.10.2009 14:14:56 DBG3] 5387 Setting dump reason to 2
[Tracing Log 08.10.2009 14:14:56 NOTICE] 5387 Installing signal handler
[Tracing Log 08.10.2009 14:14:56 DBG2] 5387 Staring trace generation
[Tracing Log 08.10.2009 14:14:56 DBG2] 5387 Tracer request startup done
[Tracing Log 08.10.2009 14:14:56 DBG3] 5387 Options updated to 7FFF
[Tracing Log 08.10.2009 14:14:57 DBG1] 5387 Tracer request shutdown
[Tracing Log 08.10.2009 14:14:57 WARNING] 5387 Code tracing buffer full
[Tracing Log 08.10.2009 14:14:57 DBG1] Using socket /usr/local/zend/tmp/monitor_events.sock rules /usr/local/zend/etc/events_rules.xml
[Tracing Log 08.10.2009 14:14:58 NOTICE] Event type 1 (0) reported
[Tracing Log 08.10.2009 14:14:58 NOTICE] 5387 Generating trace dump, format 2
[Tracing Log 08.10.2009 14:14:58 DBG2] 5387 Dump name is /usr/local/zend/var/codetracing/dump.5387.1
Monitoring Event was triggered

Functional Examples
Uncaught exceptions
Destructor being called
Prepared Statements

Where did all my memory go?
Memory usage
Large variable going out of scope

Impact

The all-important question…
“Where should I use this?”
Development – Possibly, though profiling and debugging may be more pertinent
Testing – Absolutely
Staging – Absolutely
Production - Absolutely
In Standby mode
Activated on a subset of servers

Questions?
Want to join in the public beta? Go to
http://www.zend.com/en/products/server/zend-server-5-new
for more information
kevin@zend.com

Additional Information

What happens when you have too much data
Need to up the zend_codetracing.buffer_size setting

Increasing the buffer size to 5MB
That’s better

Settings

Application Diagnosis with Zend Server Tracing

by ZendCon on Nov 02, 2009

Accessibility

Categories

Tags

Upload Details

Usage Rights

1 Embed 4

Statistics

Application Diagnosis with Zend Server Tracing — Presentation Transcript