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Think about Loose Coupling

Re^3: Saving and Loading of Variables

by idsfa (Vicar)
on Jul 18, 2006 at 23:47 UTC ( #562161=note: print w/replies, xml ) Need Help??

in reply to Re^2: Saving and Loading of Variables
in thread Saving and Loading of Variables

me elides a long post which was made totally wrong by your clarification of the data

The updated data is much more helpful, but still leaves some significant questions. For instance, the order in the hash keys of your combined tests does not seem to be related to the order in which they appear in the log file (compare "BAYES_99+URIBL_SBL" v. "URIBL_SBL+SPF_HELO_SOFTFAIL"). The "Totals" seem to imply that they are gathered over multiple runs, while "Value" is obviously the sum of the conditions matched by the current message only. And to be fair, this is the first time you mentioned wanting to record the combined score. I think your requirements need better definition: exactly what are you trying to measure?

There is no way to guarantee that all of your processed data will be saved (think power failure). You need to decide what an acceptable level of data loss is. You will need to write out the current state to a checkpoint file (whether through a database, Storable, Data::Dumper or whatever) at least once before you exit. The more often you checkpoint, the less data you risk losing. The truly paranoid will note that you need some sort of transactional locking to protect against interruption in mid-update.

You could install a signal handler to catch most of the things that could kill your program and have it checkpoint your current status. It won't work for non-maskable signals (or power cuts), but might help with your stated aversion.

For the task you describe, you might want to consider just rotating your logs nightly (or hourly, depending upon your volume) and processing them "offline" rather than tailing the live log file. It avoids most of these concerns.

The intelligent reader will judge for himself. Without examining the facts fully and fairly, there is no way of knowing whether vox populi is really vox dei, or merely vox asinorum. — Cyrus H. Gordon

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Re^4: Saving and Loading of Variables
by madbombX (Hermit) on Jul 19, 2006 at 16:28 UTC
    Your correct about the data loss thing. I am ok with slight loss (meaning about 100 messages or so) and my plan was to write the information out to a file every 100 messages. I can deal with some data loss.

    Its not so much that multiple runs are made, but that the message tests will be iterated a few times in order to get the combination values needed. Meaning aside from the BAYES_XX+TEST_X combination (which will be counted every time, I will specify which test(s) I want to catch in combination (which will require multiple iterations over a message). For instance, if I find that URIBL_SBL hits frequently in SPAM messages, then I will want to see what also hits frequently in SPAM messages and I will have a URIBL_SBL+TEST_Y category that will be created and "Totaled". The "Value" will always be the same is more for reference purposes than anything else.

    This all again brings me back to my question of what is the best way to store all this information on disk? Data::Dumper, Storable, FreezeThaw (amongst others) have been suggested, but I am curious as to the most efficient method for large amounts of data considering that it isn't just hashes and arrays but semi-complex data structures as well.

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[jedikaiti]: Hi Monks
[GrandFather]: HI jedikaiti. Collected more 73p data this morning. Rubbish sky though. Seeing was between 5 and 9 arc seconds FWHM with thin cloud drifting through :(
[GrandFather]: Still, at least some of the images are good enough to get reasonable astrometry. Well, good enough for a good plate solve anyway

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