I've Googled this question and can't seem to find a consistent opinion, or many opinions that are based on solid data. I simply would like to know if using the wildcard in a SQL SELECT statement incurs additional overhead than calling each item out individually. I have compared the execution plans of both in several different test querie...
I currently have a query that ends ORDER BY RAND(HOUR(NOW())) LIMIT 40 to get 40 random results. The list of results changes each hour. This kills the query cache, which is damaging performance. Can you suggest an alternative way of getting a random(ish) set of results that changes from time to time? It does not have to be every hour ...
I apologize if this has been asked before, but I haven't quite found the specific question I have in my head. For the website I am building (using ASP.NET MVC) - performance is an important feature. Also, there is a chance that the site could be hosted in an environment where the Application Pool gets recycled every 20 minutes (or soone...
HTTP 1.1 allows 2 connections per host name. On the other hand, yahoo performance rules suggest to reduce the number of DNS look ups. how does one balance this? thanks ...
I need a fast replacement for the System.Collections.Generic.Dictionary<TKey, TValue>. My application should be really fast. So, the replacement should support: Generics Add Get Contains ... and that's it. I don't need any support in LINQ or anything. And it should be fast. A simple code like: Stopwatch stopWatch = Stopwatch.StartN...
Continuing some themes in this question, I would like to know if I could get a performance of O(log n) on the size of the table from somes sqlite queries. The first would get the mth element of a table ordered by weight: select id, weight from items order by weight limit 1 offset m The second would do the opposite, get mth position o...
Hello all, I have read some articles about this matter... and it seems that the Repeater is the one with best performance as explained in this other question: I know that the GridView is the heaviest of them all, and that it weights a lot in the ViewState. So the DataList has been the "best" option for some situations. But how about D...
I have the following click event. protected void btnUpdate_Click(object sender, EventArgs e) { foreach (GridViewRow gvr in gvEditBulletins.Rows) { RadEditor re = (RadEditor)gvr.FindControl("reBulletin"); DropDownList ddl = (DropDownList)gvr.FindControl("ddlPosition"); // Business logic ...
I am reading up on Linq and the author uses both query expressions and dot notation. He says that the query expression is translated to the dot notation. So is it true that dot notation is faster? ...
how set sort_area_size in oracle 10g and what size should be as i have more than 2.2m rows in single table. and please tell me the suggested size of SORT_AREA_RETAINED_SIZE as my queries are too much slow they takes more than 1 hours to complete. (mostly) please suggest me the way by which i can optimize my queries and tune the database...
I've got a simple select query which executes in under 1 second normally, but when I add in a contains(column, 'text') into the where clause, suddenly it's running for 20 seconds up to a minute. The table it's selecting from has around 208k rows. Any ideas what would cause this query to run so slow with just the addition of the contains...
What are the best tools for profiling C/C++ applications on *nix? (I'm hoping to profile a server that is a mix of (blocking) file IO, epoll for network and fork()/execv() for some heavy lifting; but general help and more general tools are all also appreciated.) Can you get the big system picture of RAM, CPU, network and disk all in on...
I have written this program for connecting and fetching the data into file, but this program is so slow in fetching . is there is any way to improve the performance and faster way to load the data into the file . iam targeting around 100,000 to million of records so thats why iam worried about performance and also can i use array fetch s...
Java garbage collector runs with priority 1, due to which it is not guaranteed that System.gc() will actually execute if called. Is there any way to change its priority? This shall enable me to run if I want. ...
If I had a single server and I had two process types A(Many processes many threads) and B(one process n-threads with n-cpu's), and I wanted to send a LARGE amount of one-way messages from A to B. Is MPI a better implementation for this than a custom implementation using: Unix Domain Sockets Windows Named Pipes Shared Memory I was thi...
Hello I have heard that we should avoid Default ASP.Net Controls, because they are heavy regarding Viewstate and etc... So I was thinkink in using , , HTML tags whenever I want to only show information, and use the Eval function to insert server-side code in a href or src atribute. But I have also heard that the Eval function is not ...
I have a query in which I am ordering a league table by a number of fields to handle the situation that some fields in the result may have the same value. I am curious as to why when subsequent fields aren't required for secondary ordering the query is still conciderably slower. Case in point is a table of items that are voted on. It co...
I have rebuilt indexes and updated statistics. The query is straightforward, with a subquery in the WHERE clause. SELECT TOP 1 * from MeetingPost_reg WHERE userid = 1234 AND meetingpost_regid <> 9999 AND DateStart < (SELECT DateStart FROM MeetingPost_reg WHERE meetingpost_regid = 9999) ORDER BY DateStart desc There is an index on da...
Do anyone come across a performance issue when deleting a first row in a 20,000+ rows Excel file using OpenXML SDK v2.0? I am using the delete row coding suggested in the Open XML SDK document. It takes me several minutes just to delete the first row using Open XML SDK, but it only takes just a second in Excel applicaton. I eventually ...
I want to know few things about ASP.NET MVC with NHibernate. Is NHibernate the best ORM used with ASP.NET MVC? If so, will NHibernate slow down the application? What can be done to improve performance of an ASP.NET MVC application with NHibernate? ...