The SimpleBatchUpload  extension uses the MW API to batch-upload files. In the simplest
case the user just goes to Special:BatchUpload, dumps a bunch of files and they are
uploaded in parallel.
I got a bug report recently  where I am not sure what to do:
"Our group has been using Extension:SimpleBatchUpload (1.5.0) extensively, but
unfortunately we are running into an issue where files are uploaded but fail to be written
as a row in the _fileData MW db table or saved to our Cargo db table."
"The problem with server communication error seems to occur more frequently when
uploading many files (20 or more) at once via drag & drop and tends to be more
problematic on faster network speeds compared to a slower one."
"No MW errors are thrown in the debug log and no glaring apache errors are seen when
the communication problem happens."
"Here is the error I see in the console for the two files showing server
communication error when trying to upload 50 images. Not sure how helpful this is:
Notice: Uncommitted DB writes (transaction from Wikimedia\Rdbms\Database::begin). in
/var/www/html/includes/libs/rdbms/database/Database.php on line 4543
In addition, I also see many files with another error: Could not store file
"/tmp/phpaFwbHh" at "mwstore://local-backend/local-public/
These problems are worse when uploading very quickly on a 1 gigabit network in our office
vs when I do it at home on a slower connection.
Is this an API bug or should the extension somehow react to the Notice from the server?
Does anyboody have an idea how to mitigate the DB issues?
Any insight greatly appreciated