Indeed, and there are edge cases, like Facebook, or Google, or whatever. The edge cases are gigantic databases that are accessed in certain specific way.
It's true that many people attempt to prematurely optimize by using Cassandra first instead of something they are already familiar with. However, when faced with some of the pains of growing an RDMBS beyond what a single box can handle, it's worth it to consider your other options. Keep in mind that if it's easy to store and make use of a huge pile of data, you're more tempted to gather that data in the first place, where 10 years ago it might have been prohibitively expensive or difficult.
There are probably less edge cases than actual NoSQL codebases, which is pretty surreal. There are more actual products then the number of people who need the products. And 99.99% of the people playing with them don't need them at all.
I can assure you that you're incorrect, but since you don't have any data to back this up, I won't bother either.
The real joke is people using them in ways that are actually slower than any RDBMS, but they think it's 'easier', usually because they never bothered to learn how JOINs work, and don't understand that it's perfectly fine to make a dozen SQL queries on a web page...that's what indexes are for.
Yes, only knuckle-dragging imbeciles are interested in new systems... *sigh*. This is an often-touted piece of flamebait that has little basis in reality. Some of the largest Cassandra users are companies who already have extensive experience scaling MySQL and other RDMBS.
While some might find that document stores like MongoDB are "easier" and use it for that reason, Cassandra has a reputation for being difficult to get started with; the reason it gets used nevertheless is because the benefits outweigh the steep learning curve.
Here are some of the actual reasons why you use Cassandra:
- No single point of failure. Every node in the cluster has the same role. This is also nice for maintenance purposes.
- Linearly scalable. Increasing the size of your cluster by N times increases the total ops/second N times.
- Tunable consistency per operation. For every read and write, you can specify how many replicas for a piece of data must respond for the operation to be considered a success. A typical strategy is requiring a quorum of replicas to respond for both reads and writes, ensuring a strongly consistent view of your data (by the pigeonhole principle) while still tolerating the failure of up to half of your replicas. If you're familiar with the CAP theorem, this lets you trade off some amount of C and A for every operation.
- It's fast (while still durable). Sub-millisecond write latencies, read latencies typically 1ms to 10ms, depending on caching, write patterns, and other factors. Pretty standard hardware with cheap rotating media drives work very well, so you don't have to buy any super-boxes.
- Multi-datacenter replication. Cassandra really does a good job of making this transparent while still giving good latencies and tunable availability/consistency.
Basing the clustering aspects of Cassandra off of Amazon Dynamo is what really brings a lot to the table here. The BigTable data model just happens to work really well with this.
Columns in Cassandra aren't analogous to columns in an RDBMS. Every row is basically a list of (key, value) pairs. This is referred to as a column, with the key being the column name. There's no requirement that rows have the same set of column names.
Typically large rows are used for indexes or timelines. In a timeline example, you might use a timestamp for every column name and store the entry as the column value. Cassandra keeps the row sorted by column name, so all of the entries in the row (timeline) will be in chronological order.
In the case of indexes, you may use one row for every indexed value (say, one row for all users from Utah, one for all from Texas, etc). Here, each column would store the row key (primary key) of a row in another column family (table) that matches that indexed value; in this case, every column might hold a userId.
The difference is the perception of competition among corporations. With the federal government, you know you don't even begin to have an option. With corporations, at least you can pretend for a while...
I ended up going with the MSG-free variety (the sodium content was roughly 1/8 that of the standard beef stock from any other brand, and 1/4 the sodium in the "low sodium" varieties), but the free market wouldn't let me avoid corn syrup as well.
It could be argued that the free-market was working correctly as despite the product range not being ideal you were still willing to buy one of them.
The free market also prioritizes making special "varieties" of products about the same way that the general population does. Consider that you might look for some of the following: organic, low sodium, MSG-free, HFCS-free, sugar-free, low-fat, made from free-range cows, gluten-free, BPA-free, locally made, and vegetarian-friendly (vegetable-based).
It's not generally cost-effective to make, ship, store, and sell all of these varieties; mandating that they all exist would be hugely expensive. So, the free market instead serves as much of the population as it profitably can. It would be too much to ask them to operate at a loss, so this is the most you could hope for. The only way to change this is to increase demand by raising awareness of issues like BPA.
No, no. Cache is orders of magnitude more expensive than RAM, and that is why we get very little.
Partially correct.
The size of cache dictates how quickly it can be accessed. This is why L1 caches are always tiny. In fact, the smaller == faster is why you see the idea of a cache repeated endlessly in both hardware and software. Eventually, you end up with regsisters -> L1 -> L2 -> [L3] -> RAM -> [SSD] -> HDD.
The cache is typically puny because that allows it to be faster. You see cache increases for the same price when it becomes afordable to have a bigger cache without latency issues.
This. The fine should be their profits from the affected products from the time they started price fixing to the time they stopped.
Even that is not enough. Even if they are caught 50% of the time, that's still a good deal for them. You have to make the expected profit (in probability terms) negative for price-fixing. In other words, (fine * probability_of_being_caught) > profits.
The Leidenfrost effect has an upper bound -- it only has maximal effect at a specific temperature. If I remember correctly, anything above ~200 C decreases the effect. So, if the ball of plasma is well over that, the effect will be minor.
I do think the Prisoner's Dilemma is a very good model for the global warming situation. If you think of it strictly in those terms, the only way to change the Nash equilibrium is to alter the benefits of the different strategies for all players. This could either mean some type of guaranteed punishment for defectors or some type of guaranteed benefit for cooperators. I think most people instinctively realize this -- but enforcing the benefits/penalties on a global scale is the difficult part.
How is such accuracy possible? What Bueno de Mesquita is not doing is predicting random events such as lottery draws. Nor does he claim to be able to forecast the movement of stock markets, the outcome of general elections or the onset of financial crises - events where millions of people have a small influence, but none is able to move the market on their own.
Rather, he confines himself to "strategic situations" where relatively small numbers of people are haggling over a contentious decision. "I can predict events and decisions that involve negotiation or coercion, cooperation or bullying," he says. That includes domestic politics, foreign policy, conflicts, business decisions and social interactions.
Now, that's not to say that he couldn't make money using the predictions, but maybe he's actually more interested in the science/mathematics side of it than the business potential?
Private schools are not the answer. I went to public and private schools. The only reason private schools perform better imo was because the students in private schools were handpicked, low risk students who came from supporting homes.
I also attended both private and public schools. The "handpicked" students were not always in private school just because they were smart or wealthy; many were there because they had one form or another of a personality disorder and needed the special attention.
The quality of teaching was pretty comparable in both schools.
I disagree. My average class size was 15 students in private school. Even assuming the same curriculum and teacher quality as a public school class, the smaller size will give better results. That said, I certainly felt that both the curricula and teachers were of a higher quality than in my public school classes.
But, assuming that the kids in private schools are, on average, brighter than those in public schools, what's the problem? Bright students do better when they work with (and compete against) other bright students. Private schools can be another way to get the "gifted" classes that many of us would like to see. I know that this (currently) would be an advantage for kids from upper and middle class families that can afford it, but maybe that's where vouchers come in?
Anyway, this isn't the point I was focusing on, so these are just my thoughts on the topic.
How about hiring some charismatic, experienced teachers who will inspire the kids on a daily basis? And they won't need higher salaries - just a nice bureaucracy and politics-free workplace.
Sure, I can agree with the feel-good part of that -- but you have to pay them a higher salary. I'm not talking about $39k instead of $34k. You can make that much interning as a software developer. People who are both charismatic and experienced are already commanding high salaries elsewhere; I doubt that hardly any of them are willing to stomach that type of pay cut unless they are reaching old age.
Now, as to whether or not public schools are the best method for educating students in general, that's a different story... but currently, widespread homeschooling and private schools are unfortunately not an option.
I wonder if the low density of these skulls will affect the on-going debate about the whether or not the sauropods held their necks and heads erect or horizontally? It will be interesting to see.
See here for info on the debate.
Now, instead of including all of the sciences that would benefit in no way from controlling an avatar on the moon, restrict that number to the *much* smaller number of geologists, astronomers, etc whose field of study would directly benefit from this. My estimate would put that around 1,000 people in the U.S. That's 1/3 of a day per year each. When they collaborate (like scientists tend to do), this could add up to quite a bit of time very quickly.
It's not only very likely, it's guaranteed that it did not form in an eruption. The rock they are considering is basically a form of granite. You can find granites in a few places, but a very common place for them to form is in a magma chamber beneath a volcano. Those may stay hot for years, allowing the magma to cool very slowly and crystals to form.
So, I would say that there are a few things that could be interesting about this. First, our granites are typically micah, quartz, and feldspar (within the continents); I wonder what ones on Mars consist of? Second, this could possibly help us to understand a bit more about the history of plate tectonics on mars. As far as I know, evidence points to tectonic activity in the past, but it's not decided.
Although the article does contain some overtones of negativity, I think this quote does really present the key importance of the issue:
"When children are spending this much time doing anything, we need to understand how it's affecting them -- for good and bad," Drew Altman, president and chief executive of the foundation.
Here are my thoughts on each item:
TV 4:29 - Almost entirely negative, I suspect; surely the overwhelming advertisements alone cancel out any benefits the few educational shows.
Music/Audio 2:31 - As a musician, I have a hard time knocking this. Premature deafness from blasting those headphones is no good, though.
Computer 1:29 - As a computer scientist, well, let's just say I'm about 10x this. It can range from really good (research) to horrible (4chan).
Video Games 1:13 - I think this is a healthy dose. Games with physical activity and (gasp) sunlight are better, but this could be worse.
Print 0:38 - I'm surprised this number even exists. I assume the majority of it is beneficial in some ways -- exposure to articulating an idea in writing, if nothing else.
Movies 0:25 - Movies are usually a bit more thought provoking than TV. A slight negative here, but it's still a small number.
Overall, I do believe there is reason for concern, but not outright panic. Let the psychologists do their work and we will only understand the effects of this better.
Obviously straight from the hors^W MS marketing department mouth.
Probably not.
Have you never heard the argument that if Microsoft were to successfully prevent piracy of Windows, it would result in a massive worldwide adoption of Linux?
This reminds me of the time that I was shooting a BB gun in a empty coul-de-sac.
A lady about a block away called the police saying that I had a shotgun and that there were shots fired (wtf? Has she ever heard a shotgun before?). The police were not particularly friendly to me either, when four cops in two cars appeared out of nowhere with their weapons drawn.
So, it's not surprising to me in the least bit that this could have happened.
Slashdot Mirror
Indeed, and there are edge cases, like Facebook, or Google, or whatever. The edge cases are gigantic databases that are accessed in certain specific way.
It's true that many people attempt to prematurely optimize by using Cassandra first instead of something they are already familiar with. However, when faced with some of the pains of growing an RDMBS beyond what a single box can handle, it's worth it to consider your other options. Keep in mind that if it's easy to store and make use of a huge pile of data, you're more tempted to gather that data in the first place, where 10 years ago it might have been prohibitively expensive or difficult.
There are probably less edge cases than actual NoSQL codebases, which is pretty surreal. There are more actual products then the number of people who need the products. And 99.99% of the people playing with them don't need them at all.
I can assure you that you're incorrect, but since you don't have any data to back this up, I won't bother either.
The real joke is people using them in ways that are actually slower than any RDBMS, but they think it's 'easier', usually because they never bothered to learn how JOINs work, and don't understand that it's perfectly fine to make a dozen SQL queries on a web page...that's what indexes are for.
Yes, only knuckle-dragging imbeciles are interested in new systems... *sigh*. This is an often-touted piece of flamebait that has little basis in reality. Some of the largest Cassandra users are companies who already have extensive experience scaling MySQL and other RDMBS.
While some might find that document stores like MongoDB are "easier" and use it for that reason, Cassandra has a reputation for being difficult to get started with; the reason it gets used nevertheless is because the benefits outweigh the steep learning curve.
2B columns in a row isn't why you use Cassandra.
Here are some of the actual reasons why you use Cassandra:
- No single point of failure. Every node in the cluster has the same role. This is also nice for maintenance purposes.
- Linearly scalable. Increasing the size of your cluster by N times increases the total ops/second N times.
- Tunable consistency per operation. For every read and write, you can specify how many replicas for a piece of data must respond for the operation to be considered a success. A typical strategy is requiring a quorum of replicas to respond for both reads and writes, ensuring a strongly consistent view of your data (by the pigeonhole principle) while still tolerating the failure of up to half of your replicas. If you're familiar with the CAP theorem, this lets you trade off some amount of C and A for every operation.
- It's fast (while still durable). Sub-millisecond write latencies, read latencies typically 1ms to 10ms, depending on caching, write patterns, and other factors. Pretty standard hardware with cheap rotating media drives work very well, so you don't have to buy any super-boxes.
- Multi-datacenter replication. Cassandra really does a good job of making this transparent while still giving good latencies and tunable availability/consistency.
Basing the clustering aspects of Cassandra off of Amazon Dynamo is what really brings a lot to the table here. The BigTable data model just happens to work really well with this.
Columns in Cassandra aren't analogous to columns in an RDBMS. Every row is basically a list of (key, value) pairs. This is referred to as a column, with the key being the column name. There's no requirement that rows have the same set of column names.
Typically large rows are used for indexes or timelines. In a timeline example, you might use a timestamp for every column name and store the entry as the column value. Cassandra keeps the row sorted by column name, so all of the entries in the row (timeline) will be in chronological order.
In the case of indexes, you may use one row for every indexed value (say, one row for all users from Utah, one for all from Texas, etc). Here, each column would store the row key (primary key) of a row in another column family (table) that matches that indexed value; in this case, every column might hold a userId.
The difference is the perception of competition among corporations. With the federal government, you know you don't even begin to have an option. With corporations, at least you can pretend for a while...
I ended up going with the MSG-free variety (the sodium content was roughly 1/8 that of the standard beef stock from any other brand, and 1/4 the sodium in the "low sodium" varieties), but the free market wouldn't let me avoid corn syrup as well.
It could be argued that the free-market was working correctly as despite the product range not being ideal you were still willing to buy one of them.
The free market also prioritizes making special "varieties" of products about the same way that the general population does. Consider that you might look for some of the following: organic, low sodium, MSG-free, HFCS-free, sugar-free, low-fat, made from free-range cows, gluten-free, BPA-free, locally made, and vegetarian-friendly (vegetable-based).
It's not generally cost-effective to make, ship, store, and sell all of these varieties; mandating that they all exist would be hugely expensive. So, the free market instead serves as much of the population as it profitably can. It would be too much to ask them to operate at a loss, so this is the most you could hope for. The only way to change this is to increase demand by raising awareness of issues like BPA.
No, no. Cache is orders of magnitude more expensive than RAM, and that is why we get very little.
Partially correct.
The size of cache dictates how quickly it can be accessed. This is why L1 caches are always tiny. In fact, the smaller == faster is why you see the idea of a cache repeated endlessly in both hardware and software. Eventually, you end up with regsisters -> L1 -> L2 -> [L3] -> RAM -> [SSD] -> HDD.
The cache is typically puny because that allows it to be faster. You see cache increases for the same price when it becomes afordable to have a bigger cache without latency issues.
This. The fine should be their profits from the affected products from the time they started price fixing to the time they stopped.
Even that is not enough. Even if they are caught 50% of the time, that's still a good deal for them. You have to make the expected profit (in probability terms) negative for price-fixing. In other words, (fine * probability_of_being_caught) > profits.
Thanks for the info. That was an interesting read. :)
That's called the Leidenfrost effect.
The Leidenfrost effect has an upper bound -- it only has maximal effect at a specific temperature. If I remember correctly, anything above ~200 C decreases the effect. So, if the ball of plasma is well over that, the effect will be minor.
I do think the Prisoner's Dilemma is a very good model for the global warming situation. If you think of it strictly in those terms, the only way to change the Nash equilibrium is to alter the benefits of the different strategies for all players. This could either mean some type of guaranteed punishment for defectors or some type of guaranteed benefit for cooperators. I think most people instinctively realize this -- but enforcing the benefits/penalties on a global scale is the difficult part.
Well, actually, they say 90%. From TFA:
According to research by the CIA, Bueno de Mesquita's model is more than 90 per cent accurate (British Journal of Political Science, vol 26, p 441).
Is that independent enough for you?
From TFA:
How is such accuracy possible? What Bueno de Mesquita is not doing is predicting random events such as lottery draws. Nor does he claim to be able to forecast the movement of stock markets, the outcome of general elections or the onset of financial crises - events where millions of people have a small influence, but none is able to move the market on their own.
Rather, he confines himself to "strategic situations" where relatively small numbers of people are haggling over a contentious decision. "I can predict events and decisions that involve negotiation or coercion, cooperation or bullying," he says. That includes domestic politics, foreign policy, conflicts, business decisions and social interactions.
Now, that's not to say that he couldn't make money using the predictions, but maybe he's actually more interested in the science/mathematics side of it than the business potential?
Private schools are not the answer. I went to public and private schools. The only reason private schools perform better imo was because the students in private schools were handpicked, low risk students who came from supporting homes.
I also attended both private and public schools. The "handpicked" students were not always in private school just because they were smart or wealthy; many were there because they had one form or another of a personality disorder and needed the special attention.
The quality of teaching was pretty comparable in both schools.
I disagree. My average class size was 15 students in private school. Even assuming the same curriculum and teacher quality as a public school class, the smaller size will give better results. That said, I certainly felt that both the curricula and teachers were of a higher quality than in my public school classes.
But, assuming that the kids in private schools are, on average, brighter than those in public schools, what's the problem? Bright students do better when they work with (and compete against) other bright students. Private schools can be another way to get the "gifted" classes that many of us would like to see. I know that this (currently) would be an advantage for kids from upper and middle class families that can afford it, but maybe that's where vouchers come in?
Anyway, this isn't the point I was focusing on, so these are just my thoughts on the topic.
How about hiring some charismatic, experienced teachers who will inspire the kids on a daily basis? And they won't need higher salaries - just a nice bureaucracy and politics-free workplace.
Sure, I can agree with the feel-good part of that -- but you have to pay them a higher salary. I'm not talking about $39k instead of $34k. You can make that much interning as a software developer. People who are both charismatic and experienced are already commanding high salaries elsewhere; I doubt that hardly any of them are willing to stomach that type of pay cut unless they are reaching old age.
Now, as to whether or not public schools are the best method for educating students in general, that's a different story... but currently, widespread homeschooling and private schools are unfortunately not an option.
I wonder if the low density of these skulls will affect the on-going debate about the whether or not the sauropods held their necks and heads erect or horizontally? It will be interesting to see. See here for info on the debate.
Thanks a lot for the info! They're sold out currently, but I'll check back in on them.
Most of the places I've looked at for these are pretty seedy. Where do you get yours from and what kind do you recommend?
Now, instead of including all of the sciences that would benefit in no way from controlling an avatar on the moon, restrict that number to the *much* smaller number of geologists, astronomers, etc whose field of study would directly benefit from this. My estimate would put that around 1,000 people in the U.S. That's 1/3 of a day per year each. When they collaborate (like scientists tend to do), this could add up to quite a bit of time very quickly.
You don't see Dick Channey out running charity organizations.
Well, he's not running them, and it's at least somewhat dirty money in my book, but there is this
It's not only very likely, it's guaranteed that it did not form in an eruption. The rock they are considering is basically a form of granite. You can find granites in a few places, but a very common place for them to form is in a magma chamber beneath a volcano. Those may stay hot for years, allowing the magma to cool very slowly and crystals to form.
So, I would say that there are a few things that could be interesting about this. First, our granites are typically micah, quartz, and feldspar (within the continents); I wonder what ones on Mars consist of? Second, this could possibly help us to understand a bit more about the history of plate tectonics on mars. As far as I know, evidence points to tectonic activity in the past, but it's not decided.
Although the article does contain some overtones of negativity, I think this quote does really present the key importance of the issue:
"When children are spending this much time doing anything, we need to understand how it's affecting them -- for good and bad," Drew Altman, president and chief executive of the foundation.
Here are my thoughts on each item:
TV 4:29 - Almost entirely negative, I suspect; surely the overwhelming advertisements alone cancel out any benefits the few educational shows.
Music/Audio 2:31 - As a musician, I have a hard time knocking this. Premature deafness from blasting those headphones is no good, though.
Computer 1:29 - As a computer scientist, well, let's just say I'm about 10x this. It can range from really good (research) to horrible (4chan).
Video Games 1:13 - I think this is a healthy dose. Games with physical activity and (gasp) sunlight are better, but this could be worse.
Print 0:38 - I'm surprised this number even exists. I assume the majority of it is beneficial in some ways -- exposure to articulating an idea in writing, if nothing else.
Movies 0:25 - Movies are usually a bit more thought provoking than TV. A slight negative here, but it's still a small number.
Overall, I do believe there is reason for concern, but not outright panic. Let the psychologists do their work and we will only understand the effects of this better.
Just don't try native compilation!
Seriously though, I believe Ubuntu currently natively compiles all of their packages for ARM ... and it takes them about 6 months.
Hah, yes, that is an accurate assumption.
Obviously straight from the hors^W MS marketing department mouth.
Probably not.
Have you never heard the argument that if Microsoft were to successfully prevent piracy of Windows, it would result in a massive worldwide adoption of Linux?
This reminds me of the time that I was shooting a BB gun in a empty coul-de-sac.
A lady about a block away called the police saying that I had a shotgun and that there were shots fired (wtf? Has she ever heard a shotgun before?). The police were not particularly friendly to me either, when four cops in two cars appeared out of nowhere with their weapons drawn.
So, it's not surprising to me in the least bit that this could have happened.