2.4. Expiring Sessions

If Interchange is using DBM capability to store the sessions, periodically expire old sessions to keep the session database file from growing too large.

   expire -c catalog

There is also an expireall script which reads all catalog entries in interchange.cfg and runs expire on them. The expire script accepts a -r option which tells it to recover lost disk space.

On a UNIX server, add a crontab entry such as the following:

   # once a day at 4:40 am
   40 4 * * *    perl /home/interchange/bin/expireall -r

Interchange will wait until the current transaction is finished before expiring, so this can be done at any time without disabling web access. Any search paging files for the affected session (kept in ScratchDir) will be removed as well.

If not running DBM sessions, use a Perl script to delete all files not modified in the last one or two days. The following will work if given an argument of a session directory or session files:

   # expire_sessions.pl -- delete files 2 days old or older

   my @files;
   my $dir;
   foreach $dir (@ARGV) {
       # just push files on the list
       if (-f $dir) { push @files, $_; next; }

       next unless -d $dir;

       # get all the file names in the directory
       opendir DIR, $dir or die "opendir $dir: $!\n";
       push @files, ( map { "$dir/$_" } grep(! /^\.\.?$/, readdir DIR));

   for (@files) {
       unless (-f $_) {
           warn "skipping $_, not a file.\n";
       next unless -M $_ >= 2;
       unlink $_ or die "unlink $_: $!\n";

It would be run with a command invocation like:

   perl expire_sessions.pl /home/you/catalogs/simple/session

Multiple directory names are acceptable, if there is more than one catalog.

This script can be adjusted as necessary. Refinements might include reading the file to "eval" the session reference and expire only customers who are not members.