I have the need to relatively quickly be able to determine if a set of files on a user's machine has been processed before by my application. The app in question uploads the files for the user to a server, and if the files have been uploaded before, it skips the upload. My plan so far has been to hash the files and then store the results...
I need to convert an open delegate (one in which the Target is not specified) into a closed one efficiently. I have profiled my code, and the cost of using CreateDelegate() to produce a closed delegate for an instance method is a significant fraction (>60%) of the overall run time (as it takes place for each new instance of the type). ...
Hello, we have migrated from gwtext to smartgwt and overall the experience is ok. However, we have big problems with the ListGrid component of SmartGWT. It is very slow if both of the following conditions are met: Internet Explorer is used 5 or more columns the speed will decrease if you add more columns up to the point where the ...
Hey, I'm trying to optimize my C++ code. I've searched the internet on using dynamically allocated C++ arrays vs using std::vector and have generally seen a recommendation in favor of std::vector and that the difference in performance between the two is negligible. For instance here - http://stackoverflow.com/questions/381621/using-array...
Here is the issue. On a site I've recently taken over it tracks "miles" you ran in a day. So a user can log into the site, add that they ran 5 miles. This is then added to the database. At the end of the day, around 1am, a service runs which calculates all the miles, all the users ran in the day and outputs a text file to App_Data. ...
Hey, I've got an performance issue in my application using a MSSQL DB. I have a Database Architecture with the following tables: Job (Primary Key: Job ID) Jobitem(Primary Key: Jobitem ID, Foreign Key: Job ID) Job2Property (Foreign Key: Job ID <-> Property ID) Jobitem2Property(Foreign Key: Jobitem ID <-> Property ID) Property (Primary ...
I'm iterating over a set of instantiations of a LINQ-to-SQL class. During this iteration, I'm making changes, flagging some for deletion and even inserting new ones in the datacontext. When I'm done iterating, I fire context.SubmitChanges() - it works, but it's amazingly slow. I'm running an express version of MSSQL 2008 locally. Also,...
Historically I've been completely against using ORMS for all but the most basics applications. My reasoning has and always has been that it's a very leaky abstraction ... mostly because SQL provides a very powerful way to retreive data from a relational source which usually gets messed up by the ORM so that you lost a lot of performance...
Is System.currentTimeMillis() the best measure of time performance in Java? Are there any gotcha's when using this to compare the time before action is taken to the time after the action is taken? Is there a better alternative? ...
I've started to use mysql_data_seek () as an easy way to roll pagination transparently into my database class by shifting the pointer and reading the current 'page'. What are the performance implications of doing this? I am only reading the data I need into PHP itself, but in most cases the SELECT covers the whole table - is this bad...
Hi, I've read that the StringBuilder type has a limit (the default is 16 characters), and when you append some text to it, beyond its limit, a new instance is created with a higher limit and the data is copied to it. I tried that using the following code : StringBuilder test = new StringBuilder("ABCDEFGHIJKLMNOP",16); test.Append("ABC")...
Hi all, I'm currently benchmarking partitioned tables with SQL Server 2005 to compare them to using two tables (a "live" table and an "archive" table) for a processing queue. The partitioning's being performed on a bit column 'archive', so that when the archive bit is set, the row automagically moves. Initial testing seems to show that...
We have some performance problems with one of our applications. I thought about using something like dotTrace to find out where the problems are, but dotTrace would probably degrade performance even more. What's the best way to profile an application that's on a prod environment w/o affecting performance too much? ...
I'm writing a plug-in for another program in C#.NET, and am having performance issues where commands take a lot longer then I would. The plug-in reacts to events in the host program, and also depends on utility methods of the the host program SDK. My plug-in has a lot of recursive functions because I'm doing a lot of reading and writing ...
What's the best in terms of speed and performance? To call the function each time you need the value (e.g mysql_num_rows, time) or to copy the return value to a local variable and use that instead. Example: Let's say that I call the time() function ten times to get the current time, would it be faster to use a local variable those ten ...
I've been using a pattern in an application where I'm setting arbitrary attributes on Expando class models in an App Engine app. This works as expected, but hasn't yet been tested with a really large data set. And over time, the number of attributes might get to be > 1000. It also makes the table in the administration console scroll fa...
This is not a question about optimizing a SQL command. I'm wondering what ways there are to ensure that a SQL connection is kept open and ready to handle a command as efficiently as possible. What I'm seeing right now is I can execute a SQL command and that command will take ~1s, additional executions will take ~300ms. This is after t...
I never got the idea of asserts -- why should you ever use them? I mean, let's say I were a formula driver and all the asserts were things like security belt, helmet, etc. The tests (in debug) were all okay, but now we want to do racing (release)! Should we drop all security, because there were no issues while testing? I will never...
Oracle START WITH ... CONNECT BY clause is applied before applying WHERE condition in the same query. Thus, WHERE constraints won't help optimize CONNECT BY. For example, the following query will likely perform full table scan (ignoring selectivity on dept_id): SELECT * FROM employees WHERE dept_id = 'SALE' START WITH manager_id is n...
I have a UITableView that show a long list of data. Use sections and follow the sugestion of http://stackoverflow.com/questions/695814/how-solve-slow-scrolling-in-uitableview . The flow is load a main UITableView & push a second selecting a row from there. However, with 3000 items take 11 seconds to show. I suspect first from the load ...