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--- litespeed_wiki:php:slow_log_lsapi [2017/12/12 19:03]
Jackson Zhang
+++ litespeed_wiki:php:slow_log_lsapi [2017/12/12 21:15] (current)
Lisa Clarke
@@ Line 1: / Line 1: @@
-====== Identify scripts that are slowing down your server ======
+====== Identify Scripts That are Slow on Your Server ======
-When working with php, you will notice that your site is taking longer to load then expected. Learning why your site is loading so slow would be great. You can do an strace but sometimes that information is not always the best to read.
+When working with PHP, you may notice that your site is taking longer to load than expected. It would be useful to learn the reason why. You can do an ''strace'' but sometimes that information is not the easiest to read.
-If you are a PHP programmer, you must have used PHP’s error_log function sometime. But PHP itself does not provide a way to find out slowly executing scripts. Slow scripts are not the ones which break your site but they slow-down everything. With PHP-FPM, there is a slow_log function, by which developers can get a trace of what functions are running longer than a specified time.
+If you are a PHP programmer, you must have used PHP’s ''error_log'' function at some point. But PHP itself does not provide a way to identify slow scripts.
-LiteSpeed uses more faster LiteSpeed API (LSPHP) instead of PHP-FPM. How to trace the slow script with LSWS and LSPHP?
+Slow scripts don't necessarily break your site, but they can be slow by themselves //and// they can slow down your server overall as they increase CPU overhead.  With PHP-FPM, there is a ''slow_log'' function, by which developers can get a trace of functions whose runtime exceeds a specified threshold.
-There is a directive, which can be placed at external application settings (WebAdmin console > Configuration > External App> Environment ).
+LiteSpeed uses the faster LiteSpeed API (LSPHP) instead of PHP-FPM.  So, what's the best way to identify slow scripts with LSWS and LSPHP?
+There is a directive which can be placed in the external application settings. Navigate to **WebAdmin console > Configuration > External App** and add the following to **Environment**:
   LSAPI_SLOW_REQ_MSECS=10000
-LSAPI_SLOW_REQ_MSECS: If set to a non-zero number, LiteSpeed Web Server will log requests into an error log file if a request takes longer than the specified number of milliseconds. This can help identify scripts that are slowing down your server.
+If ''LSAPI_SLOW_REQ_MSECS'' is set to a non-zero number, LiteSpeed Web Server will log requests into an error log file if a request takes longer than the specified number of milliseconds. This can help to identify scripts that are slowing down your server.
 {{ :litespeed_wiki:php:lsapi_slow_req_msecs_conf_example.png?600 |}}
+The output of the slow script trace is written to ''stderr.log'' in the LiteSpeed log directory.  An example message would look like this:
+   [12/Dec/2017:15:37:41] Slow PHP script: 10993 ms
+     URL: GET /wordpress/index.php
+     Query String:
+     Script: /home/user/olsws/Example/html/wordpress/index.php
+There may be many of these messages.  Note that script slow-downs tend to appear in groups around the time of highest CPU load. When looking to identify what is slowing down a script, a good place to start is with the script's author.