Mysql server goes away when Idiorm's record updates

[tashemi]

I have a script where user can attach file to the record. File is stored separately (not in a database). When user does not attach file and click on "Save record" it works fine. When user attaches file it does next steps:

1. File uploads correct
2. Script takes from DB record details using Idiorm ($dbItem)
3. Script updates field "filesize" on the record ($dbItem->Size = "28 Mb")

4. Script tries to save record, and I get this:

   PDOException
   
   Code: HY000
   
   Message: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away
   
   File: /home/../includes/idiorm.php
   
   Line: 1675

I found out 2 things:

1. script returns "General error: 2006 MySQL server has gone away" only when uploaded file is bigger than 20 Mb and I try to update database with $dbRecord->save(). Sql query generated by Idiorm:

UPDATE `downloads` SET `Text` = 'Product caption', `Status` = 'Normal', `Type` = 'Demoversion / Release', `Size` = '28.05 MB' WHERE `downloadID` = '14'

1. script does not return "General error: 2006 MySQL server has gone away" when uploaded file is bigger than 20 Mb and I do not try to update record.
2. I can upload file bigger than 20 Mb and run raw query with Idiorm::raw_exec() and catch no error.

Does Idiorm do something wrong?

[tashemi]

The Problem was the "wait timeout" setting in MySQL. But still it is interesting why plain sql via raw_exec() works fine and update via save method on Idiorm object causes delay that Mysql goes away. Is it so big difference in performance?

[treffynnon]

No. This is because Idiorm opens a connection (https://github.com/j4mie/idiorm/blob/master/idiorm.php#L225) for all it's interactions and re-uses (https://github.com/j4mie/idiorm/blob/master/idiorm.php#L1592) that connection. raw_execute() on the other hand opens a connection each time it is called (https://github.com/j4mie/idiorm/blob/master/idiorm.php#L373).

[tashemi]

@treffynnon thanks for response. now reason of this error looks completely clear for me.