How to determine if I have runaway memory usage

[DannyVarley]

I am having an issue with the following:
PHP Fatal error: Out of memory (allocated 37748736) (tried to allocate 16384 bytes) in ....../public_html/includes/classes/db/mysql/query_factory.php on line 44

I am trying to figure out exactly what is causing the extreme memory usage as I have 1028mb set of PHP in the server settings which I believe to be quite large.

For this reason I think its possible a plugin I am using which could be causing the error.

What would be the best method for determining the memory problem

Thanks!

[Shop Suey]

if possible start watching the php process with top / htop

[DannyVarley]

Thanks, I will take a look!

I am trying to understand more of the log error file
PHP Fatal error: Out of memory (allocated 37748736) (tried to allocate 16384 bytes)

If I convert this value to Megabytes we get:
PHP Fatal error: Out of memory (allocated 37.748736) (tried to allocate 0.016384 bytes)

If my php.ini is currently set to 1024MB how im not sure how I am getting this fatal error as I believe there should be memory left over?

Can someone explain where I am going wrong with my thoughts?

[carlwhat]

....Can someone explain where I am going wrong with my thoughts?

trying to fix this error by expanding available memory is never a good idea.

fixing the script that is using memory without care is always a better solution.

that is what is wrong with your thoughts.

best.

[DannyVarley]

Thanks Carl,

I totally agree however Im not really an experienced developer so I have come to the forum to see if I can gain some help! See my initial question:
"What would be the best method for determining the memory problem?"

Expanding the memory was something that was done by my host after trying to get help from them for the same issue. I am aware that I have an issue with a script somewhere but how would be the best method of finding the culprit?

Cheers

[lat9]

That out-of-memory condition can be caused by a never-ending loop. The most common is a while loop that fails to increment the condition it's looking to finish.

For example:

while (!$query_results->EOF) {
//- Do stuff
$query_results->MoveNext();
}

... but missing the $query_results->MoveNext, so that the loop never reaches its completion.

[lat9]

The root-cause of this issue (IMO) was a collection of known attackers (as identified by https://ipdata.co) hammering on the site.

The issue was exacerbated by the site's setting of the SQL_CACHE_METHOD to 'database', so that every hit was resulting in a database insert/update.