I am writing a client-side .NET application which is expected to use a lot of threads. I was warned that .NET performance is very bad when it comes to concurrency. While I am not writing a real-time application, I want to make sure my application is scalable (i.e. allows many threads) and is somehow comparable to an equivalent C++ applic...
Hello, I have an empty table that previously had a large amount of rows. The table has about 10 columns and indexes on many of them, as well as indexes on multiple columns. DELETE FROM item WHERE 1=1 This takes approximately 40 seconds to complete SELECT * FROM item this takes 4 seconds. The execution plan of SELECT * FROM ITEM ...
I have a cron job that updates a large number of rows in a database. Some of the rows are new and therefore inserted and some are updates of existing ones and therefore update. I use insert on duplicate key update for the whole data and get it done in one call. But- I actually know which rows are new and which are updated so I can also...
I have a C# application that adds some performance counters when it starts up. But if the registry HKEY_LOCAL_MACHINE->SOFTWARE->Microsoft->Windows NT->CurrentVersion->Perflib is corrupted (missing or invalid data), the operation of checking the existence of the performance counters (PerformanceCounterCategory.Exists(category) takes a re...
Hi, I'm using latest version of Xampp on 64bit Win7. The problem is that, when I use mysql_connect with "bool $new_link" set to true like so: mysql_connect('localhost', 'root', 'my_password', TRUE); script execution time increases dramatically (about 0,5 seconds per connection, and when I have 4 diffirent objects using different conne...
The following query takes more than 3 minutes to run because tables contain massive amounts of data: SELECT RTRIM(LTRIM(A.HEAD)), A.EFFECTIVE_DATE, FROM TABLE_1 A WHERE A.TYPE_OF_ACTION='6' AND A.EFFECTIVE_DATE >= ADD_MONTHS(SYSDATE,-15) MINUS SELECT RTRIM(LTRIM(B.head)), B.EFFECTIVE_DATE, ...
Hi, following the text book, I do measure performance whenever I try optimizing my code. Sometimes, however, the performance gain is rather small and I can't decisively decide whether I should implement that optimization. For example, when a fix shortens an average response time of 100ms to 90ms under some conditions, should I impleme...
I have a website that makes heavy use of AJAX. There is an almost constant transfer of sensitive data. Because of this I was thinking of running my full website in HTTPS, making it secure throughout your stay. I was wondering if there are any downsides doing this. Performance is a huge issue for me, the faster the app runs the better. ...
I am working on a wpf application. In which I am working with a TreeView, each node represents different datatypes, these datatypes are having properties defined and using data template to show their properties. My application reads from xml and create tree accordingly. My problem is that when I load it, it is too slow, I want to know ab...
I have many (>600) EPS files(300 KB - 1 MB) in database. In my ASP.NET application (using ASP.NET 4.0) I need to retrieve them one by one and call a web service which would convert the content to the JPEG file and update the database (JPEGContent column with the JPEG content). However, retrieving the content for 600 of them itself takes...
I have been searching the web for recent benchmarks measuring Grails overall performance compared to its competitors (Rails, Django, ASP.NET MVC...), but I didn't find anything more recent than a 3 years-old article with obsolete grails version (0.5). See here and here. So, starting from grails 1.2, are there any more recent grails ben...
How to find the worst performing queries in SQL Server 2008? I found the following example but it does not seem to work: SELECT TOP 5 obj.name, max_logical_reads, max_elapsed_time FROM sys.dm_exec_query_stats a CROSS APPLY sys.dm_exec_sql_text(sql_handle) hnd INNER JOIN sys.sysobjects obj on hnd.objectid = obj.id ORDER BY max_logical_r...
I want to calculate the execution time of my ASP.NET pages and display it on the page. Currently I'm calculating the execution time using a System.Diagnostics.Stopwatch and then store the value in a log database. The stopwatch is started in OnInit and stopped in OnPreRenderComplete. This seems to be working quite fine, and it's giving ...
If all that you're doing is a simple one-pass iteration (i.e. only hasNext() and next(), no remove()), are you guaranteed linear time performance and/or amortized constant cost per operation? Is this specified in the Iterator contract anywhere? Are there data structures/Java Collection which cannot be iterated in linear time? java.uti...
I'm using Sybase 12.5.3 (ASE); I'm new to Sybase though I've worked with MSSQL pretty extensively. I'm running into a scenario where a stored procedure is really very slow. I've traced the issue to a single SELECT stmt for a relatively large table. Modifying that statement dramatically improves the performance of the procedure (and rever...
I use std::tr1::shared_ptr extensively throughout my application. This includes passing objects in as function arguments. Consider the following: class Dataset {...} void f( shared_ptr< Dataset const > pds ) {...} void g( shared_ptr< Dataset const > pds ) {...} ... While passing a dataset object around via shared_ptr guarantees its e...
I am wondering about the performance of this index: I have an "Invalid" varchar(1) column that has 2 values: NULL or 'Y' I have an index on (invalid), as well as (invalid, last_validated) Last_validated is a datetime (this is used for a unrelated SELECT query) I am flagging a small amount of items (1-5%) of rows in the table with thi...
I asked a question yesterday which got answers but didnt answer the main point. I wanted to reduce amount of time it took to do a MINUS operation. Now, I'm thinking about doing MINUS operation in blocks of 5000, appending each iterations results to the cursor and finally returning the cursor. I have following: V_CNT NUMBER ...
Trying to answer a question to come up with a testing plan. It has to do with using a website and/or webservice that queries a sql server to get data and display to user. * Solution must be able to handle an estimated 2000 users, approximately 700 concurrent users, 10,000 + website hits a month. Database calls should handle ...
I am developing large data collecting ASP.Net/Windows service application-pair that uses Microsoft SQL Server 2005 through LINQ2Sql. Performance is always the issue. Currently the application is divided into multiple larger processing parts, each logging the duration of their work. This is not detailed and does not help us with anything...