in reply to Re: hash on memory or disk?
in thread hash on memory or disk?

Does this test for an empty hash use a lot of memory if the hash is big?
$nmail->relay('<>',1) unless keys %$hash_ref;

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Re: hash on memory or disk?
by Abigail-II (Bishop) on Jan 14, 2004 at 11:30 UTC
    No, keys in scalar context just returns the number of elements of the hash; and the hash keeps score in its internal datastructure.

    This is of course assuming we are talking about a normal hash. If the hash is tied, then it will depend on the implementation.

    Abigail

[reply]

      Thanks for your reply.

      I have managed to reduce some of the memory usage (because I'm able to process more of the log now) but my program is still crashing. I'm having a problem tying the hashes whose elements are arrays e.g. 

      tie %recipientqids, 'MLDBM', "/home/u752359/recipientqids.db", O_CREAT
+|O_RDWR, 0640 or die $!;
push(@{$recipientqids{$hostqid}},$recipient);
..
..
foreach $hostqid( @{$msgidqids{$msgid}}){
        foreach $recipient (@{$recipientqids{$hostqid}}){
                print STDERR "\nrecip= $recipient";
        }
}

      [download]

      doesn't print anything if I tie the recipientqids hash.

      Is my syntax wrong, or can you not store these structures with MLDBM?

      Thanks,

      js1

[reply]
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