in reply to flocking databases

You should read turnstep's File Locking tutorial. While databases are not mentioned, the concept is same - your database (which you didn't mention, but i happen to know is a DBM_File *) is a single file, which can be locked just like an 'ordinary' file (whatever that is ;)).

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

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Re: (jeffa) Re: flocking databases
by sulfericacid (Deacon) on Apr 14, 2003 at 09:10 UTC
    Thanks for your help everyone. I spent days looking for documentation on flocking databases but literally found nothing because I was told it was totally different than flocking just a basic filehandle. In any case the link jeffa tossed up was the solution to my problem.

    Who would have thought flocking a file could be so easy? All you do is add the line flock(FILEHANDLE, NUM) || die; :)

    "Age is nothing more than an inaccurate number bestowed upon us at birth as just another means for others to judge and classify us"

    sulfericacid

[reply]
[d/l]

      And that is bad advice for this context. Working with dbm style files isn't like working with plain files. Originally the Perl Cookbook used such an approach and while I can't find an exact mention of the problem there's a quick overview at What about table and file locking?.

      So - if you follow only the advice in the link jeffa gave you then you'll be only part way there. In general, if you've got flock() in your code and you're working with a database then you did something wrong.

      jeffa didn't help you here at all. Bad jeffa.

[reply]
        Usually i am good about saying stuff like "here is some more advice to go along with diotalevi's even more excellent advice." This time i didn't. bad jeffa.

        diotalevi, if you are upset that sulfericacid did not take your advice to use BerkeleyDB, then i am sorry that i carved a "path of least resistance" for sulfericacid. That is not what i meant at all. Since sulfericacid did not (apparantly) know about anything about file locking at all, i thought "why not ask him to read one of our tutorials?" I think you would rather sulfericacid had read that tutorial than not ... now sulfericacid has some background to work with. That's good.

        sulfericacid ... now that you know about file locking, you really should give BerkeleyDB a whirl. Then, once you have mastered that, try out the even cooler SQLite (by the way ... DBD::SQLite is merely the Perl driver for SQLite). SQL is indeed a hurdle you have to spend time to overcome ... but once you learn it, when the time comes to start using a real RDMS (Postgres, MySQL, Oracle, etc.) you will already be ready for it.

        Oh, and since no one has said it yet ... turnstep++ for her excellent tutorial. ;)

        jeffa

        "The path of least resistance always leads you to the least everytime." -- Ty Hagar
[reply]

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