performance

Performance of setting img src to unchanged value?

If I have an img tag like <img src="example.png" /> and I set it via myImg.src = "example.png"; to the same value again, will this be a no-op, or will browsers unnecessarily redraw the image? (I'm mainly interested in the behaviour of IE6-8, FF3.x, Safari 4-5 and Chrome.) I need to change many (hundreds of) images at once, and man...

Core Data not returning NSMutableArray property

Dear all I'm starting to feel rather stupid - I've browsed the site and found a few things that come close to my problem but just can't figure it out (help M. Zarra, after reading your book I felt pretty good about Core Data but now I'm at my wits' end!). Despite the expert's advice I've chosen to store an NSMutableArray as a transforma...

Performance testing. How to increase hdd operations stability

I try to simulate application load to measure application performance. Dozens of clients send requests to server and significant part of request processing is random data loaded from HDD (random file, random file offset). I use 15 Gb in 400 files. HDD does its best to cache reading operations so overall performance is very unstable f...

New project Python 3x PostgreSQL 9x and pg8000 1x DBAPI?

I'm starting some new projects and want to know if pg8000 is considered a good choice for a production project? Obviously Python and PostgreSQL are mature products, but I'm concerned about pg8000 both when it comes to maturity and performance. Will my DB access suffer or will it be acceptable? So, please take some latitude in respondin...

Performance of WPF Image rendering

I have a ListBox containing a large number of Image controls. The Source of each Image is set to a URI on a remote server. About 20 images are visible at a time (the panel is a VirtualizingStackPanel), and each time the ListBox is scrolled it takes a few seconds to render the images, resulting in extremely sluggish scrolling. The images ...

Steps involved in the running of an exe.

Question: When we run an exe(assume by double clicking), where all the time is spent before it actually starts executing ? a) Loading of the exe onto the memory b) ? c) ? Background of the question: I am profiling the execution of an application(App.exe) and trying to improve its performance. I have a test that does something li...

Mixing percent and fixed CSS

This is a duplicate from UI.StackExchange.com: http://ui.stackexchange.com/questions/1004/mixing-percent-and-fixed-css Should you ever apply percentage and fixed CSS together? Will it cause problems, and if so what kinds? Does mixing degrade browser render performance? Will mixing give you weird results on initial load with progress...

JPA+Hibernate(J2SE) @OneToMany - Millions of records slows adding a new object down.

Hello, I'm using JPA+Hibernate with a PostGre SQL database in a J2SE project. I have 2 entities A and B. A has a @OneToMany relationship to B. In my domain model A might reference millions of B's. When I add a new object to the collection it takes minutes to complete. @OneToMany(cascade=CascadeType.PERSIST) Collection<B> foo = new Arra...

How expensive is committing a hibernate transaction?

Hi, I have a the following use case where I'm receiving a message via JMS regarding an entity, via a unique property of it (not PK) and it requires me to update the state of the entity: HibernateUtil.beginSession(); HibernateUtil.beginTransaction(); try{ Entity entity = dao.getEntityByUniqueProperty(propertyValue); if (ent...

Is there a more efficient way to get the length of a 32bit integer in bytes?

I'd like a shortcut for the following little function, where performance is very important (the function is called more than 10.000.000 times): inline int len(uint32 val) { if(val <= 0x000000ff) return 1; if(val <= 0x0000ffff) return 2; if(val <= 0x00ffffff) return 3; return 4; } Does anyone have any idea... a cool bi...

Hibernate tuning for high rate of inserts and selects per second

Hello, We have a data acquisition application with two primary modules interfacing with DB (via Hibernate) - one for writing the collected data into DB and one for reading/presenting the collected data from DB. Average rate of inserts is 150-200 per second, average rate of selects is 50-80 per second. Performance requirements for both...

SSRS Performance when first opening Browser....

I have a set of reports using SSRS on a dedicated Reports server. Our reports are launched via hyper links on an aspx page. The hyper links open a report (in a new broswer) with selectable paramaters. There is no data when the reports initially load. However, the first time loading a report in the browser takes a significant amount o...

Is there any way to see what part of a code is making a webpage slower?

It is all of the sudden much slower then it was. Is there any way I could use some sort of tool that will tell me what part of my code is making my page slow? Thanks ...

MySQL Multiple databases schemas to update => performance

Hi you all, I have thousands of databases schema to update (add a column, update some rows and add 3 rows in 2 different tables). I have 2 different approaches to do so: 1) Put the name of each schema before table names # database A01be91a86 UPDATE A01be91a86.ACTION set CODE_QUALIFICATION.... ALTER table A01e02a697.IMPRESSION add co...

Will TFS performance be degraded by having too many user workspaces?

Will TFS performance be degraded by having too many user workspaces? Our IT group observed that development has many workspaces leftover from users who have moved on, and would like development to clean them up. We currently have about 30 active users in TFS. There are probably 10 inactive users with workspaces. I didn't think worksp...

Creating & Editing performance counters in a powershell script or command line

Hello, I'm trying to move the verification & creation of my performance counter groups, and the counters themselves, out of my web service and into a powershell script that's run during deployment. Can this be done? Or am I stuck using a simple app to build the groups & counters? Thanks much :) ...

When to return values in PHP?

Hello there! Given this ugly method: public function convert_cell_value( $val, $type ) { if($type == 'String') { return $val; } elseif($type == 'Number') { if($val - intval($val) > 0) { return $val; } else { return intval($val); } } ...

Max number of Activities!

Is there any design guideline on the number of Activities an application could have? If there is a limit, what would be the ideal number of Activities that can be bundled in an Android application. ...

Which query will execute faster in MySql

Hi folks, I created indexing on my tables and then I fire same queries using two different ways:I run those queries on MySql but always got different execution time sometimes first one is faster and sometimes second..Thats why I want experts opinion on this.Queries are First one is select t1.field from table1 as t1 w...

Why would you use an HTTP Module over ASP.NET Health Monitoring or visa versa?

I have come across this question several times, you need to do some performance testing (request process times, load times, etc) or track unhanded exceptions. The answers usually come down to writing a HTTP Module, hook into specific events and log them somewhere, or use the built in health monitoring? Why would we use one over the othe...