WTF ? A transaction is either committed or not comitted... how can a transaction be "half-comitted", while other users are trying to access the same data supposedly under the impression that they are seeing the state of the database either before or after (but NOT in the middle) of any other transaction ?
Why does this scare me ? Maybe I'm just a Linux Dweeb who doesn't like terminology like half-committed.
Correct me if I'm wrong, but transactions are usually implemented using a transaction log as an intermediate queue... i.e. a transaction that does an UPDATE will end up queued on the transaction log, because another transaction is already performing a "SELECT * FROM", and as it encompasses thw whole dataset of the table, it cannot be changed by another transaction until that transaction has completed.
My original point is that backups are always bound by disk I/O, and while hotcopies can speed this up by simply doing a cp *.MYD, *.MYI etc, rather than converting the files back into raw SQL that essentially reloads the table from scratch, I still feel that using replication allows a zero downtime solution, and allows much better control of the exact snapshot point of the backup itself.
Sorry if my knowledge it limited predominently to MyISAM tables, this has been my domain for a lot of years, and somehow I've never quite trusted InnoDB tables due to the reported time needed to do things like adding columns etc (it's bad enough on MyISAM).
The thing with hot backups, is that for one or two tables, it's great... try 200 or 300, with all tables locked while the raw database files are copied, and we are talking longer than 2 or 3 minutes. And believe me, you MUST stop all writes to ANY table during the hotcopy process, otherwise all you'll end up with is a bunch of tables with screwed up referential integrity.
Also, as the GP stated, gzipped raw SQL dumps compress very nicely. Try compressing a mysql MYI (index file), and you'll save nothing, as it's already in compressed b-tree format.
Doing a true dump from a replicated copy means zero downtime, as you can simply disable the replication slave, do the dump, bring replication back up and let it catch up on the statements still in the log. And in case your server really is fried, you can even load the SQL dumps back into a different (more modern) version of the database system on a newer server.
Try using hotcopied files, and you may run into version incompatibility problems...
Yes well it cures-all aspects of culpability when shit gets left in public places... "Oh, sorry, we realise that it was us who wanted to know every aspect of your online habits (for the children doncha-know), but it wasn't us who lost it, it was the (non prosecutable) corporates we outsourced to.
Unless you fancy killing your production server for 45 minutes while he dumps out a 1.5GB table with numerous indexes (thus locking the table for any writes), I'd suggest this policy.
Replicate the database onto a second server, and on that server, do all of the above. Believe me, it saves a lot of pain and disk grinding on your production server.
Splitting what could essentially be a 1 page article into 15 pages, just to cram in needless advertising and SEO links to blogs and social networks does NOT a slideshow make.
Just call a spade a damn spade, please.
Bread Knives cut bread, but they can ALSO kill people. Cars take people to work, but they can ALSO kill people. Dogs are nice pets, but they can ALSO kill people.
With that logic, maybe we should just ban everything, just in case ?
US Bailout = 700 billion dollars mostly to banks and financial institutions who have been putting profit over people for years.
US Population = circa 300 million.
So let's just give every man woman and child a nice Christmas Gift of $2,333 (that they can use to pay their mortgage or buy food or whatever), and let those useless fatcats declare bankrupcy, and start over with a more regulated model.
There is no way to politely respond to this statement because it presents only two alternatives.
Either the writer is a linux nerd who thinks that trawling though newsgroups and forums just to find source for a driver for a damn USB camera and then compiling with the kernal 1.2.3.4 and gcc compiler 2.3.4 is normal (as opposed to the windows method which is "plug it in and it works").
Or the writer is lying... it usually takes closer to two weeks, and even then he is happy to accept that only 90% of everything works properly, because "hey it's free, what do you expect".
Didn't they ALREADY jack up prices and reap insanely great profits ? I thought selling overpriced hardware together with locked in software was their entire business model ?
The market share of Apple is directly proportional to the number of people with more money than sense, a number which in this current global crisis is fortunately decreasing.
Yes, in principle, real time video streaming NEEDs higher priority because of the nature of "real time" as opposed to "deferred" file transfer.
But in practice, this implys that "User A's video is MORE important than User B's file".
I'm sorry, but some asshole who simply MUST view a movie in "HD 1080" realtime, when there's plenty of compressed alternatives that take up a fraction of the bandwidth AND still deliver a reasonable quality video does not get any more sympathy than an asshole sharing a torrent on max ul/dl 24/7.
Then put a big goddamn disclaimer at the top of the website, that
"This site requires you to load all the ads, to support it's existence - if you don't wish to view the ads, please leave now"
Let's see how much traffic you get...
Don't make something free, and then accuse me of stealing because I don't support your financing model.
It's like those damn "historical centres that are free to enter, but then you get mugged by some well-meaning 50-somthing biddy with a collection box on the way out".
Now, I'm not saying that people shouldn't play games or that these people are necessarily addicts, but the internet should not replace all social interaction.
Have you actually SEEN a group of teens socially interacting ?
Just last week, myself and a couple of mates were out at a bar (bear in mind we're all late 30's)... and on the next table were 6 tweenies... every damn one of them with their heads down, thumbing away on their cellphones to god knows who ? The only time they'd even acknowledge the other members of the table was when their was a break in the incessant beep beep beep, and they'd be forced to actually look at each other and perhap mutter a few words.
This isn't just the internet, it's a general symptom of technology, and maybe people's inborn lack of decency... the minute someone interrupts you mid-sentence because they HAVE to answer a bloody text message... it's like being told "you are not important to me, I'd much rather talk to this anonymous person" on gadget XYZ.
If we go out, cellphones are on silent, and usually ignored... we go out to spend time with our mates, not with our gadgets.
In other words, watch your creations live out their lives with a certain degree of indirect influence.
Sound just like the typical Parent-Child relationship - at least if my 20 year old daughter (who is driving me crazy with her choice of boyfriends), is anything to go by.
Slashdot Mirror
"unwind any transactions that got half-committed"
WTF ? A transaction is either committed or not comitted ... how can a transaction be "half-comitted", while other users are trying to access the same data supposedly under the impression that they are seeing the state of the database either before or after (but NOT in the middle) of any other transaction ?
Why does this scare me ? Maybe I'm just a Linux Dweeb who doesn't like terminology like half-committed.
Correct me if I'm wrong, but transactions are usually implemented using a transaction log as an intermediate queue ... i.e. a transaction that does an UPDATE will end up queued on the transaction log, because another transaction is already performing a "SELECT * FROM", and as it encompasses thw whole dataset of the table, it cannot be changed by another transaction until that transaction has completed.
My original point is that backups are always bound by disk I/O, and while hotcopies can speed this up by simply doing a cp *.MYD, *.MYI etc, rather than converting the files back into raw SQL that essentially reloads the table from scratch, I still feel that using replication allows a zero downtime solution, and allows much better control of the exact snapshot point of the backup itself.
Sorry if my knowledge it limited predominently to MyISAM tables, this has been my domain for a lot of years, and somehow I've never quite trusted InnoDB tables due to the reported time needed to do things like adding columns etc (it's bad enough on MyISAM).
The thing with hot backups, is that for one or two tables, it's great ... try 200 or 300, with all tables locked while the raw database files are copied, and we are talking longer than 2 or 3 minutes. And believe me, you MUST stop all writes to ANY table during the hotcopy process, otherwise all you'll end up with is a bunch of tables with screwed up referential integrity.
Also, as the GP stated, gzipped raw SQL dumps compress very nicely. Try compressing a mysql MYI (index file), and you'll save nothing, as it's already in compressed b-tree format.
Doing a true dump from a replicated copy means zero downtime, as you can simply disable the replication slave, do the dump, bring replication back up and let it catch up on the statements still in the log. And in case your server really is fried, you can even load the SQL dumps back into a different (more modern) version of the database system on a newer server.
Try using hotcopied files, and you may run into version incompatibility problems ...
I'll stick with my method anyway.
Yes well it cures-all aspects of culpability when shit gets left in public places ... "Oh, sorry, we realise that it was us who wanted to know every aspect of your online habits (for the children doncha-know), but it wasn't us who lost it, it was the (non prosecutable) corporates we outsourced to.
Unless you fancy killing your production server for 45 minutes while he dumps out a 1.5GB table with numerous indexes (thus locking the table for any writes), I'd suggest this policy.
Replicate the database onto a second server, and on that server, do all of the above. Believe me, it saves a lot of pain and disk grinding on your production server.
Splitting what could essentially be a 1 page article into 15 pages, just to cram in needless advertising and SEO links to blogs and social networks does NOT a slideshow make. Just call a spade a damn spade, please.
There is no spoon !
You ARE a lemming ...
Bread Knives cut bread, but they can ALSO kill people.
Cars take people to work, but they can ALSO kill people.
Dogs are nice pets, but they can ALSO kill people.
With that logic, maybe we should just ban everything, just in case ?
Yes, the whole thing would have been FAR more accessible as a 40000 character perl regex.
Dumbass, go troll your anti-ms propaganda elsewhere :-(
When did Microsoft go into the disk drive business ?
Go spread your anti-ms bs somewhere else please.
Silvio owns EVERYTHING !!!
Hmm let's see ...
US Bailout = 700 billion dollars mostly to banks and financial institutions who have been putting profit over people for years.
US Population = circa 300 million.
So let's just give every man woman and child a nice Christmas Gift of $2,333 (that they can use to pay their mortgage or buy food or whatever), and let those useless fatcats declare bankrupcy, and start over with a more regulated model.
Linux NATIVELY supports more devices than Vista ?
Or Linux simply wraps the Windows version driver and then claims it counts as "1 more we support" ?
FUD works both ways.
There is no way to politely respond to this statement because it presents only two alternatives.
Either the writer is a linux nerd who thinks that trawling though newsgroups and forums just to find source for a driver for a damn USB camera and then compiling with the kernal 1.2.3.4 and gcc compiler 2.3.4 is normal (as opposed to the windows method which is "plug it in and it works").
Or the writer is lying ... it usually takes closer to two weeks, and even then he is happy to accept that only 90% of everything works properly, because "hey it's free, what do you expect".
Didn't they ALREADY jack up prices and reap insanely great profits ? I thought selling overpriced hardware together with locked in software was their entire business model ?
The market share of Apple is directly proportional to the number of people with more money than sense, a number which in this current global crisis is fortunately decreasing.
About 27 nanoseconds after the first blogging software was created.
Yes, in principle, real time video streaming NEEDs higher priority because of the nature of "real time" as opposed to "deferred" file transfer.
But in practice, this implys that "User A's video is MORE important than User B's file".
I'm sorry, but some asshole who simply MUST view a movie in "HD 1080" realtime, when there's plenty of compressed alternatives that take up a fraction of the bandwidth AND still deliver a reasonable quality video does not get any more sympathy than an asshole sharing a torrent on max ul/dl 24/7.
Then put a big goddamn disclaimer at the top of the website, that
"This site requires you to load all the ads, to support it's existence - if you don't wish to view the ads, please leave now"
Let's see how much traffic you get ...
Don't make something free, and then accuse me of stealing because I don't support your financing model.
It's like those damn "historical centres that are free to enter, but then you get mugged by some well-meaning 50-somthing biddy with a collection box on the way out".
Yes, I know preview is my friend ... and I know how to close a tag ... I just had a temporary brain fart and forgot, okay ?
Not just run right out (literally) and buy it because it looked fast and shiny in a commercial.
Erm, this IS Apple we are talking about. Their fanbois' mantra is "ooo, shiny".
"fast AND shiny" is definately worth another $100 on the retail.
Oh, the possibilities ...
"The iPhone ... so simple any cunt can use it !!!"
In Soviet Russia, Advertised Burger Photoshops You !
Sorry, just couldn't resist ...
Surely
"Duh" = "OMG! You are so stupid and you don't even see it. [Looks around] Is everyone with me here?"
"Uh" = Something French people say when trying to speak English because they can't think quietly ? ...)
(Ooops, now I've done it
Now, I'm not saying that people shouldn't play games or that these people are necessarily addicts, but the internet should not replace all social interaction.
Have you actually SEEN a group of teens socially interacting ?
Just last week, myself and a couple of mates were out at a bar (bear in mind we're all late 30's) ... and on the next table were 6 tweenies ... every damn one of them with their heads down, thumbing away on their cellphones to god knows who ? The only time they'd even acknowledge the other members of the table was when their was a break in the incessant beep beep beep, and they'd be forced to actually look at each other and perhap mutter a few words.
This isn't just the internet, it's a general symptom of technology, and maybe people's inborn lack of decency ... the minute someone interrupts you mid-sentence because they HAVE to answer a bloody text message ... it's like being told "you are not important to me, I'd much rather talk to this anonymous person" on gadget XYZ.
If we go out, cellphones are on silent, and usually ignored ... we go out to spend time with our mates, not with our gadgets.
In other words, watch your creations live out their lives with a certain degree of indirect influence.
Sound just like the typical Parent-Child relationship - at least if my 20 year old daughter (who is driving me crazy with her choice of boyfriends), is anything to go by.