Exporting Structure and Data (Backup) - Mastering phpMyAdmin 3.1 for Effective MySQL Management - page 121

• __DB__ would generate marc_book.sql

__DB__-%Y%m%d

• would give marc_book-20071206.sql

The remember template option, when activated, stores the entered template settings
into cookies (for database, table, or server exports) and brings them back the next
time we use the same kind of export.

The default templates are configurable, via the following parameters:

$cfg['Export']['file_template_table'] = '__TABLE__';
$cfg['Export']['file_template_database'] = '__DB__';
$cfg['Export']['file_template_server'] = '__SERVER__';

Compression
To save transmission time and get a smaller export file, phpMyAdmin can compress
to ZIP, GZIP, or BZIP2 formats. phpMyAdmin has native support for the ZIP format.
However, the GZIP and BZIP2formats work only if the PHP server has been compiled
with the --with-zlib or --with-bz2 configuration option respectively. The following
parameters control which compression choices are presented in the panel:

$cfg['ZipDump'] = TRUE;
$cfg['GZipDump'] = TRUE;
$cfg['BZipDump'] = TRUE;

A system administrator installing phpMyAdmin for a number of users could choose
to set all these parameters to FALSE , so as to avoid the potential overhead incurred
by a lot of users compressing their exports at the same time. This situation usually
causes more overhead than if all the users were transmitting their uncompressed
files at the same time.

In older phpMyAdmin versions, the compression file was built in the web server
memory. Some problems caused by this were:

• File generation depended on the memory limits assigned to running

PHP scripts.
During the time the file was generated and compressed, no transmission

•

occurred. Hence, users were inclined to think that the operation was not
working and that something had crashed.
Compression of large databases was impossible to achieve. •

The $cfg['CompressOnFly'] parameter (set to TRUE by default) was added to
generate (for gzip and bzip2 formats) a compressed file containing more headers.
Now, the transmission starts almost immediately. The file is sent in smaller chunks
so that the whole process consumes much lesser memory.