Just had a thought...

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Just had a thought...

Postby Bazza » Wed Nov 21, 2012 6:14 pm

Does deleting all the spammers from the database cause memory leaks and/or memory fragmentation and would this be a method of attempting to cause a system crash?

Just a thought...
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Postby bobthebob1234 » Wed Nov 21, 2012 6:59 pm

Why would deleting things cause cause memory leaks and/or memory fragmentation?? :shock:

PHPBB usually runs on PHP&MySQL, last time I checked deleting things from MySQL doesn't cause memory leaks...

Updating and deleting lots can cause a little overhead on the MySQL tables, but that is very quick and easy to get rid of...
For certain you have to be lost to find the places that can't be found. Elseways, everyone would know where it was
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Postby nelz » Wed Nov 21, 2012 7:21 pm

Also, this is a very small number of transactions, each one has to be done manually.
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Postby Bazza » Fri Nov 23, 2012 6:47 pm

Is the database not stored in RAM then for sheer speed?

It was only a passing thought, I am not a database man
but a HW oriented man instead.
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Postby guy » Fri Nov 23, 2012 8:14 pm

It may all be loaded into RAM if it is small enough and there is enough RAM. But even so, every change (commit) must be saved to a non-volatile medium such as a hard disc, so that the system can recover it following an outage.

But you are right that deleting direct from the database can cause a crash. When say a user account is deleted directly, any post by that user will still link back to the account. and if someone views the post & clicks through, the software will probably assume that the account is still there to be linked to. If it isn't, expect the unexpected, such as a crash. Safer to delete posts & other fingerprints first, then the account. GUI tool designers tend to think of these sorts of things, so mandraulic GUIs tend to be more robust than direct database queries (e.g. allowing admins to lock the account but leaving out a "delete" button). And usually mandraulics is the only way to drive the GUI.
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Postby Bazza » Fri Nov 23, 2012 9:50 pm

Thanks Guy...

I am purely a hobbyist computer user and......

The only reason why I asked the question in the first place was
because of the recent attack of spammers. As I wrote earlier I
am no expert on database related stuff but I can see events
that might occur on large sized database files loaded into
memory.

By adding new spammers, then, them being deleted just
increases memory load which eventually overruns into a disk
based swapfile and/or causes system lock up or crash due to
out of memory error. Much akin to a buffer overrun, but on
a much larger scale...

Thanks a lot, you answered my question admirably.

CYA...
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Postby nelz » Fri Nov 23, 2012 11:11 pm

guy wrote:But you are right that deleting direct from the database can cause a crash. When say a user account is deleted directly, any post by that user will still link back to the account. and if someone views the post & clicks through, the software will probably assume that the account is still there to be linked to.


When a user is deleted their posts still appear with their username, but there is no profile link, so you can't try to view a non-existent user that way. If you load the page while they are still a user but follow the link after they have been deleted, you just get a no such user page.
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Postby 1slipperyfish » Sat Nov 24, 2012 5:30 pm

Bazza wrote: but a HW oriented man instead.

hard work??
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Postby nelz » Sat Nov 24, 2012 9:23 pm

1slipperyfish (troll) wrote:hard work??


Yes, you are :P
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Postby 1slipperyfish » Sun Nov 25, 2012 12:51 pm

nelz wrote:
1slipperyfish (troll) (troll) wrote:hard work??


Yes, you are :P

sudo apt-get i'm-lost
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Postby heiowge » Sun Nov 25, 2012 2:17 pm

1slipperyfish (troll) (troll) wrote:
nelz wrote:
1slipperyfish (troll) (troll) (troll) wrote:hard work??


Yes, you are :P

sudo apt-get i'm-lost


sudo apt-get lost.


Sorry. Couldn't resist! :twisted:
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Postby 1slipperyfish » Mon Nov 26, 2012 5:12 pm

heiowge wrote:
1slipperyfish (troll) (troll) (troll) wrote:
nelz wrote:
1slipperyfish (troll) (troll) (troll) (troll) wrote:hard work??


Yes, you are :P

sudo apt-get i'm-lost


sudo apt-get lost.


Sorry. Couldn't resist! :twisted:

that's what i said but these pesky moderators keep changing my posts :x
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Postby Dutch_Master » Mon Nov 26, 2012 5:53 pm

Gee, I wonder why.... :roll:

It was so nice and quiet here with you absent fishy one, what have we done wrong to get you back? Or rather: what went wrong elsewhere that made you come back, gotten your ar*e kicked around in that place? :twisted:
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Postby Rhakios » Mon Nov 26, 2012 7:34 pm

Dutch_Master wrote:Gee, I wonder why.... :roll:

It was so nice and quiet here with you absent fishy one, what have we done wrong to get you back? Or rather: what went wrong elsewhere that made you come back, gotten your ar*e kicked around in that place? :twisted:


Surely you noticed that 1sf (troll) reappeared just around the time of the spam flood? Coincidence? I think not!


:wink:
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Postby 1slipperyfish » Mon Nov 26, 2012 7:46 pm

yo dm always a pleasure :P i haven't been anywhere else but here :? where i belong :D
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