Mon, 17 Dec 2007 09:48:57 +0000
Every month or two someone in the CEP community makes a statement like “Hey, there is more to complex event processing than processing simple streams!” or “SQL and rules are not the final chapter in the saga of event processing!”
Everytime, there are a few voices in the CEP community who argue that there is really nothing more than stream processing and they give the same simple examples to prove their case.** It is obvious, at least to me, that*they have*never worked in large scale network management or cybersecurity; yet they claim to have most, if not all*of,*the answers, a very simple construct which applies to all complex problems.* They seemingly argue and debate every point or detail that they do not understand.
This reminds me of the*age old*story of the fish, famous in Asian studies.
This fish lives in a vast ocean, wide and deep, full of life.** In fact, the entire world of the fish is the deep blue*sea.** The*fish does not know of the land and understands very little, if anything,*about the sky.*** The fish is quite content in*its beautiful world of the sea.* Why would it know of the land?
One day a*frog*tells this very happy*fish about incredible wonders beyond the sea*and air breathing creatures that live on the land.****
The fish strong denies any possibility and discounts the entire story by his friend the*frog.* In fact, the fish says there is only water, and only sea creatures, and only vast oceans and deep blue seas.* The fish goes on to say*it has never seen this dry place called land, or met any of these funny creatures that move freely on the land with legs and without gills.* “What a ridiculous story,” says the fish!
Regardless of the frogs good intentions to inform our good friend the fish about the wonders of the land, the fish simply cannot accept the frog’s story about the land, because the entire world of the fish is this beautiful deep and vast ocean.** There is no dry land!*
The same is true in the CEP community.** The world is full of complex event processing applications than cannot be solved by rules, time-ordered stream processing and strict determinism.* In fact, most of the more interesting problems are simply too complex to fit neatly into some rigid set of rules with strict determinism.
There is complexity and complexity theory, probability and statistics.** There are tradeoffs between detection sensitivity and false alarms, very difficult problems without solutions.
The fish*cries out*“don’t waste my time with folly about this nonexistant place called land!”
Likewise, a small group of folks in the CEP community who*are steadfast in their*debate in the idea that there is more than simple event processing, and we call this,
Complex Event Processing (CEP)
I've a situation here, I have a big file which contains about 20Million line as shown as below
I want to fish out some lines according to the line position of the big file, for example here line number 3,4,7 ...
so the expected output will be like this
currently I manage to... (3 Replies)
Originally, we only had one shell on unix. When ran a command, the shell would attempt to invoke one of the exec() system calls on it. It the command was an executable, the exec would succeed and the command would run. If the exec() failed, the shell would not give up, instead it... (3 Replies)