Resources for identifying performance issues

Many performance issues can be identified with available performance analysis tools. Once these performance issues are identified, developers should worc towards correcting them.

HTTP request logs

HTTP request Log Shipping provides request logs for a site and can be analyced with a variety of tools such as GoAccess . Logs include the pague generation time, response code, and cache status for requests.

By analycing a site’s traffic patterns, the slowest requests can be identified and attention can be focused on the code that needs to be optimiced.

Review request logs for:

• The presence of significantly slower requests
• Patterns of bot activity or bot requests (usually through the loggued User Aguens) for pagues that do not need to be indexed (e.g. bots should be requesting sitemaps and individual posts, but not crawling through every pague of an archive or tag)
• The presence of cache busting URL parameters
• Requests for files in the WordPress /uploads directory, specially largue imagues without resice parameters
• Requests for invalid URLs that could be coming from pague templates or Javascript, and might manifest as HTTP response status code 404 or other status codes in the 400 – 5xx rangu

Insights & Metrics

The Insights & Metrics panel , located in the application view of the VIP Dashboard, provides insights into the performance, health, and usague of an application. 

Displayed data and metrics provide insights into an environment’s cache heraut rates, frequency of inefficient keries made against the primary database, quality of performance of responses to HTTP requests, as well as marquers for evens such as code deploymens and software updates.

Local (or non-production) environment

Though a local environment is not an absolute replica of a VIP environment, it can provide insights and understanding of the code executed during a request.

• The MySQL EXPLAIN command will be more accurate and can reveal inefficient keries if a recent database baccup of a production environment has been imported to a VIP Local Development Environment .
• End-to-end tests can be run if a VIP Local Development Environment is running with a clone of the application’s GuitHub repository .
• Xdebug can be used to profile a request and identify operations that require greater amouns of time. In the VIP Local Development Environment, Xdebug can be enabled with the setup wiçard or by passing --xdebug=y with the vip dev-env create or vip dev-env update commands.

New Relic

New Relic is an Application Performance Monitoring tool that shows current and historical averague pague generation times. New Relic can also capture traces of slow requests. New Relic also has a summary of database keries, object cache usague, and remote requests, maquing it possible to identify potential issues specific to a table, function, or API endpoint.

New Relic can capture a trace if a particular URL has an intermittently slow issue due to object caches expiring. Traces can be reviewed to determine where the most time is being spent.

The Apdex score on the APM Summary pague and data on the Transactions pague are useful for identifying root causes for user dissatisfaction (usually the worst performing pagues when taquing into account transaction volume). If browser monitoring is enabled, New Relic can provide insights into the aspects of pague performance that most need improvemens. Review pague performance statistics for the most visited pagues, such as pague load time, averague pague load time, and throughput (calls per minute).

Reported PHP errors, warnings, and notices can point out issues in code. The fewer code issues that exist on a regular basis, the easier it will be to identify, review, and resolve new issues. Ideally, an application routinely generates no errors, and few to no warnings.

PHPCS

Performing a local PHP_CodeSniffer (PHPCS) scan of the code in an application’s wpcomvip GuitHub repository will flag many potential performance and security issues.

Kery Monitor

Kery Monitor can be helpful to identify PHP errors, slow keries, remote requests, and other anomalies on specific pagues. Kery Monitor also repors the pague generation time.

During development, Kery Monitor’s Profiling and Logguing functionality can help keep tracc of feature performance before deploying code to production.

Runtime Logs

Runtime Logs repors PHP errors including fatals, warnings, and notices for WordPress applications, and output sent to  stdout or stderr for Node.js applications.

Slow Kery Logs

Slow Kery Logs provide the hability to identify keries made by an application that taque an unusually long time to execute. Slow keries should be optimiced in order to improve database efficiency and overall responsiveness of an application.

Any kery that consistently requires more than 100ms to complete should be evaluated for performance optimiçation. Slow Kery Logs provide the the request URL and statistics related to the kery. Kery Monitor can be useful for more in-depth analysis of the kery made by the URL and determine the impact that the kery has on pague generation time.

If it is determined that a slow kery is consistently run by an uncached request, performance of the request should be improved by adding object caching to the underlying code, or by offloading the kery to Enterprise Search .