I have a update query that runs slow (see first query below). I have an index created on the table PhoneStatus and column PhoneID that is named IX_PhoneStatus_PhoneID. The Table PhoneStatus contains 20 million records. When I run the following query, the index is not used and a Clustered Index Scan is used and in-turn the update runs ...
I am suffering from abysmal INSERT times on my MacPro (quad-core 6G memory) running mysql 5.1.49 on snow leopard 10.6.4. I tried to figure out where the problem is and finally came to the conclusion that it must have to do with Mac OS X. Here is the test I ran. I have an old dell with a single pentium cpu and 256M memory and mysql 5.1.4...
I've heard a lot about the importance of using sprites in order to get your request count down. But my thinking is that rather than use sprites, you can use URIs to accomplish the same thing, and much easier (no sprite creation needed). Is it better to use sprites or uris? ...
I'm working with a legacy database that stores GUID values as a varchar(36) data type: CREATE TABLE T_Rows ( RowID VARCHAR(36) NOT NULL PRIMARY KEY, RowValue INT NOT NULL ) INSERT T_Rows (RowID, RowValue) VALUES (NEWID(), 1) I would assume that storing a GUID as a uniqueidentifier would be preferable since it's o...
I have a query that runs in about 5 seconds on Postgres 8.4. It selects data from a view joined to some other tables, but also uses the lag() window function, ie. SELECT *, lag(column1) OVER (PARTITION BY key1 ORDER BY ...), lag(...) FROM view1 v JOIN othertables USING (...) WHERE ... For convenience I created a new view that simply h...
I've been told by my company's support team that some versions of java have a significant performance impact when we turn on -verbose:gc. However I can't figure out if this is the case or not. Was this logging slow(ish) at some point, and when did it stop? The reason I ask is that there's some hesitation about applying this to a produ...
The important technologies i use are: Glassfish v3, JSF 2.0, JPA 2.0, EclipseLink 2.0.2, log4j 1.2.16, commons-logging 1.1.1. My problem is that some parts of the application are pretty slow. I analysed this with the netbeans 6.8 Profiling capabilities. I. Logging - i use log4j and apache commons logging to generate logs in a logging ...
Hi! I have an F# quotation that I manipulate (I add object pools everywhere to recycle short lived objects that get created and deleted very often). I would like to run the resulting quotation; for now I have used the F# PowerPack which offers methods to convert a quotation to an expression tree and the to a delegate, which I run. Having...
There is any difference in performance between the operator IS NULL and the function ISNULL() ? ...
I'm trying to get a better handle on how threads work in ASP.NET, so I have a test site with a few pages, and I have a test WinForms client that creates 40 roughly concurrent requests to the test site. The requests take about 5-10 seconds to complete--they call a web service on another server. When I run the test client, I can use Fiddle...
Hello! Is adding tablespaces to a database decrease the performance of an Oracle 9 database? We consider that the number of request remains constant. Thx, Eric ...
I'm about to use func_get_args for reading additional arguments of a function call. How does this affect the performance? Should I rather use an array for passing additional arguments instead of reading them with the function above? ...
I have a general question about WPF performance. We have a relatively simple forms application. Some team members believe that redesigning the templates for basic controls will improve performance and maintainability. One preferred technique is to create multiple control templates for a control, and swap them out with triggers. The belie...
Working on different projects I have the choice of selecting different programming languages, as long as the task is done. I was wondering what the real difference is, in terms of performance, between writing a program in Python, versus doing it in C. The tasks to be done are pretty varied, e.g. sorting textfiles, disk access, network...
Hi, I have written a module. I wanted to test the run-time performance of the module (processor and other resource utilization) on various platforms, like on a Netbook, Laptop, Android Mobile Phone etc. I would like to monitor the performance of only the thread that is running my module and not the overall resource/processor utilizati...
I have a table that contains a few columns and one of them is an md5 hash which is a unique key in the table. What would be the most efficient engine and index type (hash/b-tree) for the purposes of determining if a hash already exists in the table or not? I expect to have billions of rows across 200 partitions (mysql5.1) Right now I ...
Given a binary application running on linux PC. Is it possible to determine if it disables the Nagle's algorithm. One way could be to see the output in wireshark and depending on the time differences. Could you please tell me a reliable way of finding it out from the wireshark output? Is there a more direct way? Can I trace the system c...
I've been using OpenLink Virtuoso as an RDF store for some time now and although it's great with large data, I'm not satisfied with the graph traversal performance using SPARQL. Recently I've heard a lot about Neo4j's traversal performance and thought it's worth a try. So, for the purpose of having a large RDF store with good traversal ...
Considering the following model: @Entity public class User { @Id @Column(name = "USER_ID") private Long userId; @Column(name = "FIRST_NAME") private String firstName; @Column(name = "LAST_NAME") private String lastName; @OneToOne @PrimaryKeyJoinColumn private UserExt userExt; ... //getters...
Hi, I want to export my instruments data. But the menu item is gray. I tried everything. How does it work? Is there any way to export CPU Sampler data? Thanks! ...