performance

问题 During working on sockets and serializing objects over them, I noticed that there are some 3rd party libraries for faster object serialization on Java such as Kryo and FST. Up to now, I expected that Java's serialization is optimized and the fastest. Because, it is language dependent and gives a low level solution that is expected to be faster. However, the considered libraries claim that they are faster than Java. Can someone explain why Java could not provide the fastest serialization

问题 I am writing some quiz game and need computer to solve 1 game in the quiz if players fail to solve it. Given data : List of 6 numbers to use, for example 4, 8, 6, 2, 15, 50. Targeted value, where 0 < value < 1000, for example 590. Available operations are division, addition, multiplication and division. Parentheses can be used. Generate mathematical expression which evaluation is equal, or as close as possible, to the target value. For example for numbers given above, expression could be : (6

问题 I am writing some quiz game and need computer to solve 1 game in the quiz if players fail to solve it. Given data : List of 6 numbers to use, for example 4, 8, 6, 2, 15, 50. Targeted value, where 0 < value < 1000, for example 590. Available operations are division, addition, multiplication and division. Parentheses can be used. Generate mathematical expression which evaluation is equal, or as close as possible, to the target value. For example for numbers given above, expression could be : (6

问题 I am writing some quiz game and need computer to solve 1 game in the quiz if players fail to solve it. Given data : List of 6 numbers to use, for example 4, 8, 6, 2, 15, 50. Targeted value, where 0 < value < 1000, for example 590. Available operations are division, addition, multiplication and division. Parentheses can be used. Generate mathematical expression which evaluation is equal, or as close as possible, to the target value. For example for numbers given above, expression could be : (6

问题 I am writing some quiz game and need computer to solve 1 game in the quiz if players fail to solve it. Given data : List of 6 numbers to use, for example 4, 8, 6, 2, 15, 50. Targeted value, where 0 < value < 1000, for example 590. Available operations are division, addition, multiplication and division. Parentheses can be used. Generate mathematical expression which evaluation is equal, or as close as possible, to the target value. For example for numbers given above, expression could be : (6

问题 I am writing some quiz game and need computer to solve 1 game in the quiz if players fail to solve it. Given data : List of 6 numbers to use, for example 4, 8, 6, 2, 15, 50. Targeted value, where 0 < value < 1000, for example 590. Available operations are division, addition, multiplication and division. Parentheses can be used. Generate mathematical expression which evaluation is equal, or as close as possible, to the target value. For example for numbers given above, expression could be : (6

问题 C++ style vs. performance - is using C-style things, that are faster the some C++ equivalents, that bad practice ? For example: Don't use atoi() , itoa() , atol() , etc. ! Use std::stringstream <- probably sometimes it's better, but always? What's so bad using the C functions? Yep, C-style, not C++, but whatever? This is C++, we're looking for performance all the time.. Never use raw pointers, use smart pointers instead - OK, they're really useful, everyone knows that, I know that, I use the

问题 Is it possible to get a history of queries made in postgres? and is it be possible to get the time it took for each query? I'm currently trying to identify slow queries in the application I'm working on. I'm using Postgres 8.3.5 回答1: There's no history in the database itself, if you're using psql you can use "\s" to see your command history there. You can get future queries or other types of operations into the log files by setting log_statement in the postgresql.conf file. What you probably

问题 The target for us to achieve is 500 concurrent users. We have tried running a test for 100 users over 3 machines. And it ran fine without any errors. When i tried running the test for 150 or More users with same number of machines, i started getting the following response code Response code:Non Http Response code:java.net.socketException Response message:Connection Reset I have also tried increasing the number of machines to 8 machines. Still it is of no help. Response time is also very high

问题 The target for us to achieve is 500 concurrent users. We have tried running a test for 100 users over 3 machines. And it ran fine without any errors. When i tried running the test for 150 or More users with same number of machines, i started getting the following response code Response code:Non Http Response code:java.net.socketException Response message:Connection Reset I have also tried increasing the number of machines to 8 machines. Still it is of no help. Response time is also very high