Re: How to drop an email and have global history

On Thu, Oct 28, 2010 at 10:20 AM,
<[email protected]> wrote:
> Matt Sergeant - [email protected] wrote:

>>> I'm guessing memcached would be useful here or a sqlite db?
>>
>> Yes or some sort of db file like BDB, though lots of people seem to have
>> reliability problems with those (myself included).
>>
> Ah ok.

this is exactly the kind of thing that DirDB is designed for and good
at. Expirations can be efficiently effected by having two DirDB hashes
like so:

     tie my %Issues0 => DirDB => "issueDB/issues0";
     tie my %Issues1 => DirDB => "issueDB/issues1";

and when you are looking something up, sanitize they key (as it will
be going into a file name) and fall back to the second one

    my $issue = do {
             my $_key = $key;
             $_key =~ s/\W/X/g; # or something -- be creative
             sleep 1 until !mkdir ("issueDB/LOCK", 0700);
             $Issues0{$_key} or $Issues1{$_key}
             rmdir "issueDB/LOCK";
    };

and do expirations by running from cron a script containing something like

     while true
     do
       mkdir issueDB/LOCK  && break
       sleep 1
     done
     mv issueDB/issues1 issueDB/issuesX$$
     mv issueDB/issues0 issueDB/issues1
     mkdir issueDB/issues0
     rmdir "issueDB/LOCK";
     rm -rf  issueDB/issuesX$$