What is tmp/assets/asset_manager_core_js.js?

Hi all,

Last friday, my web application piwik went down ! I restored the directory web/html in the previous night situation, and all come back fine !
I searched the difference between before and after the restoration. It seems the file tmp/assets/asset_manager_core_js.js was missing just before the restoration.
What is the function of this file ? and what can be the origin of its lost ?
I already had exactly the same problem, one week before (friday too), at about the same hour.
I still have 4 days to prevent the next occurrence :slight_smile:
Thx for your help



Matomo merges all JS files used by the core application and all plugins into a single file, which gets loaded by the browser.
But I am not sure why this breaks for you. Every file in tmp/ simply gets regenerated when you delete it (you could try deleting everything in tmp/)
Maybe check the php error log or other system logs if something happend when the file disappeared.

Hello all,

Thx Lukas, for your answer. I tried to examine my logs files, but without result… And always the same problem : once or twice a week, the file tmp/assets/asset_manager_core_js.js disappear, and piwik go down ! When it works, and I check system under piwik admin, I have a warning, to indicate that this file has an integrity problem, and recommand to delete it… and wait it re-create it. But, it never happen !

Is there anybody can tell me what is the event to create this file ? What program or circumstance triggs the creation of this file ? How to force it ?

This problem has occured in 3.0.4. We hoped to resolve it with upgrade in 3.2.1… but exactly same behaviour with the 2 versions


The file will be created as soon as you load the UI and the JS file is requested by the browser. If this does not work, there might be likely write permission issues or maybe memory or timeout issues. Maybe check how long the request in the browser takes. Possible your server is maybe slow or does not have enough memory .