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Analyzing Performance Issues

Forum|Forum|2 years ago
October 25, 2023
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While using the system, users may encounter slowness and performance issues. The root causes of these issues vary based on usage patterns, application design, system resources, and external factors.

For the purposes of this guide, “slowness” is defined as an aspect of the application or platform not responding within an expected, defined range. For example:

As an end user, page loads take longer than pre-defined SLAs or seems slow
As a designer, Health Check or logs indicate a response time above the defined threshold

This guide is designed to help teams methodically investigate reported issues and identify root cause(s) by performing the following steps:

Document Issues
Triage Issues
Analyze Issues

Document Issues

Your team needs detailed information about the performance issues in order to start the analysis process. A simple email stating that “the system is slow” is not actionable. In order to collect this information, your team must first provide guidance to end users on how to document performance issues. You may also need to train your support staff on how to collect this information. This ensures that the responding team has a sufficient level of information to quickly triage and analyze an issue.

The following list provides the minimum data points that should be collected by your support team or by the end users themselves when they experience a performance issue:

Name of the user reporting the issue
Username of user experiencing the issue
URL of the Appian environment
Date and time of issue
User's environment (e.g. browser type and version, use of VPN/virtual desktop)
Steps to reproduce the observed behavior, noting specific screens and/or record/reference IDs related to latency
If the issue is experienced in a browser, recording of the network logs captured using the browser’s Developer Tools could be useful. See “How to generate a browser network capture (HAR) file” for more information

Encourage the person documenting the issue to be as detailed as possible: What is slow? How slow? What data did you enter?

Sample Issue Report

Reporter	John Smith
Username	john.smith
Site URL	https://myapplication.domain.com/suite/sites/mysite
Time of issue	Between 10:00am and 10:30am EST
Environment	Windows 10, IE Edge - over VPN
Issue Summary / Reproduction Steps	I logged in as john.smith and executed the Create Record action from the Finance site. I filled out the "Enter Basic Information" screen with my name and address, and added 10 locations. I clicked Submit, and the system took approximately 30 seconds before displaying the second form ("Enter Additional Details"). I expected the second form to appear within 5 seconds.

Type:
Value:

Triage Issues

Performance issues can occur anywhere in an application so the first thing to do is to triage and categorize the reported issues. Looking at the environment metrics in My Appian is a great place to start to determine if performance could be impacting the wider the platform.

First, confirm the validity of the usage patterns triggering the reported issue(s). Invalid usage might best be resolved through training or application guardrails rather than in-depth performance analysis and tuning.

Some example questions to help you decide this are:

Do users have realistic expectations?
- Is the user seeing SLA violations for response times?
- Is the reported issue tied to an area of the application that is expected to run longer, such as a large report?
Are users utilizing the system as intended? Can users do something they shouldn’t be able to do?
- Exporting millions of records, or processing extremely large file upload might not be expected or valid.
If performance testing, is the test realistic?
- Poorly designed tests (i.e. higher than expected volume) may result in performance issues.
- See the Performance Testing Methodology for guidance on test creation and validation.

Analyze Issues

Initial Analysis

Once you've confirmed your application is not performing as expected, your first goal should be to isolate the problem to a specific area of your platform. Start by following the tree below. Once you have reached an endpoint, navigate to the appropriate section below for more information. Restart the decision tree as analysis dictates.

Detailed Analysis

Network/VPN

If all web interactions are slow, including those not associated with Appian, then your issue is likely related to your network connection or specific computer rather than the platform. Check these things first to confirm:

Key Questions

Potential Issues

Next Steps

Relevant Logs And Tools

Are you on VPN/Citrix, etc.?

Latency is sometimes introduced by intermediate web proxies like VPN or Citrix

Diagnose
- Check with peers to see if there is latency on direct network access
Action
- Engage IT/Network support team

Network logs

Are your peers experiencing similar latency?

Issues may be isolated to your machine or region

Diagnose
- Verify if issues are specific to your location (i.e. floor, office, network connection)
Action
- Try different connection
- Engage IT/Network support team

Network logs

Web Layer

If your web layer interactions are slow:

Key Questions	Potential Issues	Next Steps	Relevant Logs And Tools
Are nodes load balancing as expected?	Load is imbalanced or otherwise not functioning correctly	Review load balancing mechanism (mod_jk, F5 device, etc.). Verify network traffic is being routed properly	Web server error logs Load balancer logs/configuration
Is the Web Server performing as expected?	Threads may be stuck, or CPU utilization may be too high for resources available	Isolate which threads/requests are causing issues	Web server access logs Web server error logs
Is granular debugging enabled?	Some debugging levels introduce unexpected latency into Web requests	Disable any extraneous debugging	Web server access logs Web server error logs Web-to-App server connector logs (ISAPI, mod_jk/mod_proxy)

App Server

Key Questions	Potential Issues	Next Steps	Relevant Logs And Tools
Is there high CPU utilization/load average?	Application server resources are overloaded	Diagnose Look into logs for high volume requests Run thread/heap dumps Review if application follows best practices or is using more resources than expected Action Optimize application to align with best practices Typical Performance Issues Database Performance Consider scaling resources if needed (i.e. add additional CPU)	Appian system.csv
Is there high heap/garbage collection time?	Application components are using a high amount of memory. Typically seen generating documents or working with very large data sets	Diagnose Look at logs for risks Action Run thread/heap dumps Consider scaling resources if needed (i.e. add additional memory) Consider adjusting Heap settings	Appian system.csv

RDBMS

If your RDBMS interactions are slow:

Key Questions	Potential Issues	Next Steps	Relevant Logs And Tools
Are your queries designed efficiently?	Queries are under/over indexed	Diagnose Run explain plan Analyze Logs Run profiler Review index statistics Action Review the Database Performance play Update indices Redesign queries	DB Slow query logs Explain plan Appian data_store.csv expression.csv smart_service*.csv perf_monitor_rdbms.csv
Are your queries running with the expected parameters?	Indexes are not being applied correctly due to unexpected where conditions or casting to unexpected types	Diagnose Run explain plan Run profiler Review index statistics Action Update indices Update application	DB Explain plan Profiler Appian perf_monitor_rdbms.csv
Is the database tuned to support volume and type of queries?	Database resources are insufficient; settings, such as buffer/cache are overwhelmed	Diagnose Monitor system resources (CPU, Disk Usage, Memory) Action Adjust settings as needed	DB System metrics Appian perf_monitor_rdbms.csv

Engines

Key Questions	Potential Issues	Next Steps	Relevant Logs And Tools
Are all engines up?	Some engines are not accessible, resulting in some requests failing or bottlenecking on limited resources	Diagnose Execute the Check Engine script and confirm all services are available Action Resolve any issues and restart any unavailable services	Appian Diagnostics scripts engine status logs engine.csv perf_monitor.csv
Are your requests load balanced?	Some execution services are being under- or over- utilized due to process design patterns	Diagnose Execute an All Process reports, and count number of processes per engine Action Review process models for instances of MNI or high number of subprocesses Update to use the Start Process service where possible, or minimize use of MNI	Appian Analytics reports Diagnostics scripts engine.csv top_models.csv top_process*.csv
Are engines overloaded?	Engines are overloaded due to high utilization (either throughput or sub-optimal design)	Diagnose Review engine performance logs for extremely low Idle time % (<20%) and Work Queue Size increasing Identify expensive processes Action Decrease utilization by optimizing expensive processes Consider scaling engines if needed	Appian Analytics reports Diagnostics scripts engine_system.csv perf_monitor.csv top_models.csv top_process*.csv

Interfaces/Expressions

If your interfaces are slow:

Key Questions	Potential Issues	Next Steps	Relevant Logs And Tools
Do your interfaces rely on external services or complex database queries?	The service isn't performant or is not functioning correctly	Diagnose Review the interface to look for integration calls (e.g. Integration objects, fn!webservicequery(), a!queryEntity()) Leverage the Performance View and logs to determine if integration calls significantly contribute to overall render time Action If integration based, review the Integrations and RDBMS sections of this guide If not, review the remaining questions in this section	Appian Performance view Application server logs expression.csv data_store.csv
Are your interfaces complicated, or call many expressions?	The time to complete numerous tasks causes the overall interface to perform slowly	Diagnose Review the Performance View to isolate redundant, high volume or poor performing sections of the interface Action Review the Interface Performance And Debugging and Database Performance plays Improve the design of the identified area Consider simplifying the interface if possible, looking for opportunities to do some of the work on other screens	Appian Performance View Application server logs expression.csv data_store.csv

Integrations

If your external integrations are slow:

Key Questions	Potential Issues	Next Steps	Relevant Logs And Tools
Is there an issue in the service?	The service isn't performant or is not functioning correctly	Diagnose Isolate performance using debugging tools to replicate transactions outside of Appian Action If test tools show issues as well, engage owner of service If test tools to not show issues, investigate Appian logs further	External Tools Fiddler, SoapUI, Postman Appian Application server logs expression.csv smart_service.csv integration*.csv HTTP Request/Response Logs
Is there any issue with connectivity to the service?	The network connection to the service is misconfigured	Diagnose Isolate performance using debugging tools to replicate transactions outside of Appian Action Engage IT/Network support team	Network logs External Tools Fiddler, SoapUI, Postman Appian Application server logs expression.csv smart_service.csv integration*.csv HTTP Request/Response Logs

Smart Services

If your smart service execution is slow:

Key Questions	Potential Issues	Next Steps	Relevant Logs And Tools
If a plugin, is the smart service code optimized?	Plug-in code might not be optimized for the parameters provided	Diagnose Debug code using logging or remote tools to isolate poor performing modules. Ensure the plug-in has been written to follow best practices. Action Update implementation	Appian Application server logs expression.csv smart_service.csv External Tools Remote or local debugging with IDEs