man DBM_Filter::compress () -
DBM_Filter::compress
SYNOPSIS
use SDBM_File; # or DB_File, or GDBM_File, or NDBM_File, or ODBM_File use DBM_Filter ;
$db = tie %hash, ... $db->Filter_Push('compress');
DESCRIPTION
This DBM filter will compress all data before it is written to the database and uncompressed it on reading.
A fatal error will be thrown if the Compress::Zlib module is not available.
SEE ALSO
DBM_Filter, perldbmfilter, Compress::Zlib
AUTHOR
Paul Marquess pmqs@cpan.org