Will enabling XDebug on a production server make PHP slower?

user_261251 0
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The title pretty much says it all...is it a bad idea ? I'd like to have the enhanced debug messages that XDebug provides on the server.

[edit] Just to make things clear. I'm aware there are security risks involved. Perhaps I should complement my question and give more precise reasons why I would want to do this.

Our production server hosts a testing platform also. Sometimes we use it to test things on a environment as close to production as possible. The main thing I'm looking for is using XDebug's enhanced var_dump().

This is not an app server for high traffic apps and performance is not that big of an issue. I was just curious if performance would be noticeably impacted by XDebug.

Besides, I guess I could enable it only for the VirtualHost that defines the testing sites.

xdebug production-environment php performance
11 Answers

Removing xdebug completely (even when it was not enabled) gave us 50% in page load boost (down from 60ms to 30ms). We had xdebug sitting "dormant" (waiting for trigger). We thought that since it's dormant it won't cause any harm, but boy were we wrong.

We commented out the zend_extension line in the php config at around 21:43. Average load dropped from 0.4 to 0.2 per core as well:

enter image description here

user_17081240

You could always clone your live server with the exactly same configuration, except that it wouldn't be public. Then you can install XDebug on it and debug things with the almost exactly the same conditions (well, load will be different between real life and the clone, but the rest will be the same). In that case you debug things on a live environment, but real live is not affected.

Note: Obviously it does not apply to anyone. Not everyone can easily clone a server. If you use cloud services like AWS etc. it would be very easy. If you use server configuration tools like Ansible, Chef, Puppet for building your server this is a piece of cake as well.

user_22633950

I know this is an old post, but since the issue with Xdebug is still there 10 years on, I'd like to point to the relevant bug report (closed as WONTFIX NOTABUG): https://bugs.xdebug.org/view.php?id=1668

Tl;dr:

Just installing xdebug will (on linux @least) slow all php on the site to a crawl, with hits anywhere from 2x to 20x, even if all flags are set to OFF. DO NOT INSTALL xdebug IN PRODUCTION - EVER. Better yet, investigate less intrusive debug options.

user_2796000

I tested the performance impact using this php benchmark tool. Disclaimer I built the tool.

The answer is the xdebug module significantly slows down code execution: from 2x to 7x times depending on the test. Here are my results:

# env information
php version        :     7.4.5
platform           : WINNT x64

# disable xdebug extension in php.ini
$ php src/benchmark.php --iterations 1000 --time-per-iteration 50 --save xdebug_off

# enable xdebug extension
$ php src/benchmark.php --iterations 1000 --time-per-iteration 50 --save xdebug_on

# compare
$ php src/compare.php --file1 benchmark_xdebug_off_20201127-0946.txt --file2 benchmark_xdebug_on_20201127-0939.txt
------------------------------------------------
test_math                  OFF       ON
mean               :      3762      531   -85.9%
median             :      4226      568   -86.6%
mode               :      4655      596   -87.2%
minmum             :       918      188   -79.5%
maximum            :      4722      612   -87.0%
quartile 1         :      3081      490   -84.1%
quartile 3         :      4580      595   -87.0%
IQ range           :      1498      105   -93.0%
std deviation      :       984       87   -91.1%
normality          :     11.0%    11.0%
------------------------------------------------
test_strings
mean               :      1419      677   -52.3%
median             :      1521      688   -54.7%
mode               :      1580      974   -38.4%
minmum             :       537       90   -83.2%
maximum            :      1629     1071   -34.3%
quartile 1         :      1319      452   -65.7%
quartile 3         :      1582      892   -43.6%
IQ range           :       262      440    67.8%
std deviation      :       226      248     9.8%
normality          :      6.6%     6.6%
------------------------------------------------
test_loops
mean               :      8131     1208   -85.1%
median             :      8617     1240   -85.6%
mode               :      9109     1407   -84.6%
minmum             :      3167      589   -81.4%
maximum            :      9666     1435   -85.2%
quartile 1         :      7390     1116   -84.9%
quartile 3         :      9253     1334   -85.6%
IQ range           :      1863      217   -88.3%
std deviation      :      1425      164   -88.4%
normality          :      5.6%     5.6%
------------------------------------------------
test_if_else
mean               :    279630    31263   -88.8%
median             :    293553    31907   -89.1%
mode               :    303706    37696   -87.6%
minmum             :    104279    12560   -88.0%
maximum            :    322143    37696   -88.3%
quartile 1         :    261977    28386   -89.2%
quartile 3         :    307904    34773   -88.7%
IQ range           :     45927     6387   -86.1%
std deviation      :     39034     4405   -88.7%
normality          :      4.7%     4.7%
------------------------------------------------
test_arrays
mean               :      5705     3275   -42.6%
median             :      5847     3458   -40.9%
mode               :      6040     3585   -40.6%
minmum             :      3366     1609   -52.2%
maximum            :      6132     3645   -40.6%
quartile 1         :      5603     3098   -44.7%
quartile 3         :      5965     3564   -40.3%
IQ range           :       361      465    28.8%
std deviation      :       404      394    -2.5%
normality          :      2.4%     2.4%
------------------------------------------------
user_101264790
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