Re: Tie, DBM's, HoH and Sparse Keys

[TheoPetersen]

I tried this (Perl 5.6.1, RedHat 6.0) and found something wierd.

checkdbm \%terms,$db;
print "hashref =", tied($terms{$db}), "\n";

prints "hashref =" and the use of uninitialized value warning. So the tiedness of the hash reference is getting lost somewhere.

[mr.nick]

Yeah, that didn't work quite as expected, so I followed runrigs suggestion and changed it to:

sub checkdbm {
  my $hashref=shift;
  my $key=shift;
  
  if (-f "$key-dbm.db") {
    return;
  }

  my %hash;

  tie (%hash,'NDBM_File',"$key-dbm",O_RDWR|O_CREAT,0640);

  $hashref->{$key}=\%hash;
}

which works .. sorta. The DB files fill with the correct information, but my memory usage isn't any less. Odd, no?

Well, off to Storable I suppose (and I was really trying to get THIS to work ... for stubborness sake).

[TheoPetersen]

If speed is not of the essence...

Could you try untying the hashes in between operations on particular top-level keys? That should release the NDBM_File buffers and what-not.