Importing Structure and Data - Mastering phpMyAdmin 3.4 for Effective MySQL Management - page 145

The time taken by the file, as it travels between the client and
the server, does not count as execution time as the PHP script
only starts to execute after the file has been received on the
server. Therefore, the $cfg['ExecTimeLimit'] parameter
has an impact only on the time used to process data (such as
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 maximum file
size that can be uploaded via HTTP. This one is obvious, but another less obvious
parameter is post_max_size . As 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 prevent web server child processes
from grabbing too much of the server's memory—phpMyAdmin runs inside 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
value can be recommended; the value depends on the size of uploaded data we
want to handle and on the size of the physical memory. The memory limit can also
be tuned via the $cfg['MemoryLimit'] parameter in config.inc.php , as seen
in Chapter 6 .
Finally, file uploads must be allowed by setting file_uploads to On ; otherwise,
phpMyAdmin won't even show a dialog to choose a file. It would be useless to
display this dialog as the connection would be refused later by the PHP component
of the web server.
Handling big export files
If the file is too big, there are ways in which we can resolve the situation. If the
original data is still accessible via phpMyAdmin, we could use phpMyAdmin to
generate smaller export files, choosing the Dump some row(s) dialog. If this were
not possible, we could use a spreadsheet program or a text editor to split the file
into smaller sections. Another possibility is to use the upload directory mechanism ,
which accesses the directory defined in $cfg['UploadDir'] . This feature is
explained later in this chapter.