performance

Does beginTransaction in Hibernate allocate a new DB connection?

Hi folks - Just wondering if beginning a new transaction in Hibernate actually allocates a connection to the DB? I'm concerned b/c our server begins a new transaction for each request received, even if that request doesn't interact with the DB. We're seeing DB connections as a major bottleneck, so I'm wondering if I should take the t...

Problem with room/screen/menu controller in python game: old rooms are not removed from memory

I'm literally banging my head against a wall here (as in, yes, physically, at my current location, I am damaging my cranium). Basically, I've got a Python/Pygame game with some typical game "rooms", or "screens." EG title screen, high scores screen, and the actual game room. Something bad is happening when I switch between rooms: the old...

WPF performance for large number of elements on the screen

Im currently trying to create a Scene in WPF where I have around 250 controls on my screen and the user can Pan and Zoom in and out of these controls using the mouse. I have run the WPF Performance Suite tools on the application when there are a large number of these controls on the screen (i.e. when the user has zoomed right out) the F...

Was Joel right about XML being slow?

A long time ago Joel explained how various every-day coding things were slow, and this led to XML as a data store being slow: Back to Basics Are those every-day coding things - strcat and malloc - still slow in a std::string and dlmalloc world? What else has changed in modern processors and mainstream frameworks? And is XML still slow...

Rails upload to s3 performance issue

Hello, I'm building an app to store files on my s3 account. I use Rails 3.0.0beta A lot of files can be uploaded at the same time, and the cost (from a performance point of view) of an upload is quite heavy, my app will be busy handling uploads all the time! Maybe a solution is to upload directly to s3, but I still need a submit to my...

Using Large Lists

In an Outlook AddIn I'm working on, I use a list to grab all the messages in the current folder, then process them, then save them. First, I create a list of all messages, then I create another list from the list of messages, then finally I create a third list of messages that need to be moved. Essentially, they are all copies of each ...

Loading only part of a bitmap file in Android

Hi all, I would like to load a cropped version of a bitmap image into a Bitmap object, without loading the original bitmap as well. Is this at all possible without writing custom loading routines to handle the raw data? Thanks, Sandor ...

Reporting System architecture for better performance

Hi, We have a product that runs Sql Server Express 2005 and uses mainly ASP.NET. The database has around 200 tables, with a few (4 or 5) that can grow from 300 to 5000 rows per day and keep a history of 5 years, so they can grow to have 10 million rows. We have built a reporting platform, that allows customers to build reports based on t...

Delphi Performance: Case Versus If

I guess there might be some overlapping with previous SO questions, but I could not find a Delphi-specific question on this topic. Suppose that you want to check if an unsigned 32-bit integer variable "MyAction" is equal to any of the constants ACTION1, ACTION2, ..., ACTIONn, where n is - say 1000. I guess that, besides being more elega...

Impact of ordering of correlated subqueries within a projection

I'm noticing something a bit unexpected with how SQL Server (SQL Server 2008 in this case) treats correlated subqueries within a select statement. My assumption was that a query plan should not be affected by the mere order in which subqueries (or columns, for that matter) are written within the projection clause of the select statement...

What's the difference between reflow and repaint?

I'm a little unclear on the difference between reflow + repaint (if there's any difference at all) Seems like reflow might be shifting the position of various DOM elements, where repaint is just rendering a new object. E.g. reflow would occur when removing an element and repaint would occur when changing its color. Is this true? ...

What's the fastest way to check if a word from one string is in another string?

I have a string of words; let's call them bad: bad = "foo bar baz" I can keep this string as a whitespace separated string, or as a list: bad = bad.split(" "); If I have another string, like so: str = "This is my first foo string" What's the fasted way to check if any word from the bad string is within my comparison string, and ...

Overhead of calling tiny functions from a tight inner loop? [C++]

Say you see a loop like this one: for(int i=0; i<thing.getParent().getObjectModel().getElements(SOME_TYPE).count(); ++i) { thing.getData().insert( thing.GetData().Count(), thing.getParent().getObjectModel().getElements(SOME_TYPE)[i].getName() ); } if this was Java I'd probably not think twice. But in performance-...

Data in two databases, eager spool resulting in query

I have two databases in SQL2k5: one that holds a large amount of static data (SQL Database 1) (never updated but frequently inserted into) and one that holds relational data (SQL Database 2) related to the static data. They're separated mainly because of corporate guidelines and business requirements: assume for the following problem th...

Need help tuning a SQL statement

I've got a table that has two fields (custno and custno2) that need to be searched from a query. I didn't design this table, so don't scream at me. :-) I need to find all records where either the custno or custno2 matches the value returned from a query on the same table based on a titleno. In other words, the user types in 1234 for th...

C++ Performance/memory optimization guidelines

Hi All, Does anyone have a resource for C++ memory optimization guidelines? Best practices, tuning, etc? As an example: Class xxx { public: xxx(); virtual ~xxx(); protected: private: }; Would there be ANY benefit on the compiler or memory allocation to get rid of protected and private since there the...

Do fluent interfaces significantly impact runtime performance of a .NET application?

I'm currently occupying myself with implementing a fluent interface for an existing technology, which would allow code similar to the following snippet: using (var directory = Open.Directory(@"path\to\some\directory")) { using (var file = Open.File("foobar.html").In(directory)) { // ... } } In order to implement su...

PHP: What is an efficient way to parse a text file containing very long lines?

I'm working on a parser in php which is designed to extract MySQL records out of a text file. A particular line might begin with a string corresponding to which table the records (rows) need to be inserted into, followed by the records themselves. The records are delimited by a backslash and the fields (columns) are separated by commas. ...

Java - When to use Iterators?

Hi all, I am trying to better understand when I should and should not use Iterators. To me, whenever I have a potentially large amount of data to iterate through, I write an Iterator for it. If it also lends itself to the Iterator interface, then it seems like a win. I was reading a little bit that there is a lot of overhead with usi...

How to utilize my computation resources.

Hi all, I wrote a program to solve a complicated problem. This program is just a c# console application and doesn't do console.write until the computation part is finished, so output won't affect the performance. The program is like this: static void Main(string[] args) { Thread WorkerThread = new Thread(new Thread...