Importing Structure and Data - Mastering phpMyAdmin 2.8 for Effective MySQL Management - page 126

Instead of using HTTP, we can upload our file to the server using a protocol like FTP,
as described in the Web Server Upload Directories section. This method circumvents
the web server's PHP upload limits.

Time Limits
First, let's consider the time limit. In config.inc.php , the $cfg['ExecTimeLimit']
configuration directive assigns, by default, a maximum execution time of 300 seconds
(five minutes) for any phpMyAdmin script, including the scripts that process data
after the file has been uploaded. A value of 0 removes the limit and in theory gives
us infinite time to complete the import operation. If the PHP server is running in safe
mode, modifying $cfg['ExecTimeLimit'] will have no effect, because the limits
set in php.ini or in user-related web server configuration file (such as .htaccess or
virtual host configuration files) take precedence over this parameter.

Of course, the time it effectively takes depends on two key factors:

•
•

Web server load
MySQL server load

The time taken by the file as it travels between the client and
the server does not count as execution time, because the PHP
script only starts to execute after the file has been received
on the server. So the $cfg['ExecTimeLimit'] parameter
has an impact only on the time used to process data (like
decompression or sending it to the MySQL server).

Other Limits
The system administrator can use the php.ini file or the web server's virtual host
configuration file to control uploads on the server.

The upload_max_filesize parameter specifies the upper limit or the maximum file
size that can be uploaded via HTTP. This one is obvious, but another less obvious
parameter is post_max_size . Since HTTP uploading is done via the POST method,
this parameter may limit our transfers. For more details about the POST method,
please refer to http://en.wikipedia.org/wiki/Http#Request_methods .

The memory_limit parameter is provided to avoid web server child processes
from grabbing too much of the server memory—phpMyAdmin also runs as a child
process. Thus, the handling of normal file uploads, especially compressed dumps,
can be compromised by giving this parameter a small value. Here, no preferred