'MySql server has gone away'

darrenm

Getting this error when trying to upload a reasonably large (1mb) binary into our database via a web form. The system is working just fine with smaller files.

I think that the PHP settings for uploads are fine - plenty of execution time, uploads and POST set to 25mb.

Are there similar settings for MySQL? I've had upload problems before but it usually results in a PHP error or white screen. For me to get my error screen returned with MySQL message the PHP script must have completed it's execution, so I'm thinking the problem is with mysql somewhere...

Any help appreciated.

Roger_Ramjet

Certainly are:

upload_max_filesize
max_execution_time
max_input_time

any one of them could be the problem

darrenm

Thank you - but those are PHP settings are they not?

The uploads are set to 25Mb and the execution time must be sufficient as the script completes. The page I have captures any MySQL errors and displays them as part of the completed output. So I know PHP hasn't timed-out.

It's the MySQL error "mysql server has gone away" that interests me - unless you believe it's possible for that to be caused by PHP rather than MySQL settings?

Darren

darrenm

Our ISP found the solution to this one in the MySQL documentation in case anyone else has the same problem:

"you can also get these errors if you send a query to the server that is incorrect or too large. If mysqld receives a packet that is too large or out of order, it assumes that something has gone wrong with the client and closes the connection. If you need big queries (for example, if you are working with big BLOB columns), you can increase the query limit by setting the server's max_allowed_packet variable, which has a default value of 1MB"

Sxooter

Note that, at least in the past, there was a 1 meg limit for MySQL queries. Later versions may be able to handle more. The limit for PostgreSQL was wrongly reported by the crash me test as being 16 megs because that was the max size the test could create. The actual limit for PostgreSQL is infinite, limited only by your hardware.

If you're mucking about with data with rows that big, you might want to just save it to the file system.