The title says it all. It never happened to me. In Visual Studio, I have a part of code that is executed 300 times, I time it every iteration with the performance counter, and then average it. If I'm running the code in the debugger I get an average of 1.01 ms if I run it without the debugger I get 1.8 ms. I closed all other apps, I re...
I've been trying to increase performance and diagnose deadlocks on a SQL Server 2005 instance. It had been running SQL Server 2000 until a month ago, when an in situ upgrade was done. After the upgrade, we've experienced a number of issues- performance is down and deadlocks are way up. MS suggested we use 2005's Database Engine Tuning Ad...
I read ConcurrentHashMap works better in multi threading than Hashtable due to having locks at bucket level rather than map wide lock. It is at max 32 locks possible per map. Want to know why 32 and why not more than 32 locks. ...
I have a query that pulls 5 records from a table of ~10,000. The order clause isn't covered by an index, but the where clause is. The query scans about 7,700 rows to pull these 5 results, and that seems like a bit much. I understand, though, that the complexity of the ordering criteria complicates matters. How, if at all, can i reduce ...
Recent JVM's have a lot of XX parameters for garbage collection (see here for example), but what are the options which can make a client side Swing application really perform better? I should note that one of the things that really annoys me on client side java applications is the large delay in stop-the-world garbage collection. In Int...
I just got this quite large CakePHP app (about 20k lines of code), which isn't very clean and there is no documentation at all. The app is running in production, but it has really major problems with performance. Server is Quad core with 8GB RAM, but the app can serve only about 3-4 requests/s, which is very very bad. Each request take...
I have a MySQL database. I store homes in the database and perform literally just 1 query against the database, but I need this query to be performed super fast, and that's to return all homes within a square box geo latitude & longitude. SELECT * FROM homes WHERE geolat BETWEEN ??? AND ??? AND geolng BETWEEN ??? AND ??? How is the b...
Oracle creates nicely HTML-formatted workload reports (AWR) that list things like instance statistics, wait events, the top ten heavy SQL statements (by number of executions, number of disk reads, and so on). Is there a similar tool for Postgresql? ...
The following queries are taking 70 minutes and 1 minute respectively on a standard machine for 1 million records. What could be the possible reasons? Query [01:10:00] SELECT * FROM cdc.fn_cdc_get_net_changes_dbo_PartitionTest( CASE WHEN sys.fn_cdc_increment_lsn(0x00)<sys.fn_cdc_get_min_lsn('dbo_PartitionTest') THEN sys.fn_...
Can anyone explain the science behind the sampling functionality of visualvm ? I would have thought that collecting the amount of CPU spent on each particular method would require instrumenting the application to be profiled, but it doesnt look like visualvm is doing any kind of instrumenting, so I'm curious to know how it's done... ...
I've been tasked with stress/load testing our company web site out of the blue and know nothing about doing so. Every search I make on google for "how to load test a web site" just comes back with various companies and software to physically do the load testing. For now I'm more interested in how to actually go about setting up a load t...
So I'm having serious speed problems using a left join to count ticket comments from another table. I've tried using a sub-select in the count field and had precisely the same performance. With the count, the query takes about 1 second on maybe 30 tickets, and 5 seconds for 19000 tickets (I have both a production and a development serve...
We have an application that generates around 100 animations at runtime and they are all added to a single storyboard and then played. The problem is that the animation is extremely slow. The objects that are being animated are shapes and splines and a good amount of computation is done in the backend for generating the custom splines. Th...
I have oracle 10g installed on windows server 2003. I have 22,000,000 records in single table and this is a transactional table, increasing of records in same table approx. 50,000 per month. My question is that whenever I run query on it always my query too slow. Is there any method by which I can improve the performance of the query, l...
Hi, we are having an application which is completely written in C. for table accessing inside the code like fetching some values from atable we use pro*C and for increasing the performance of the application we also preload some tables for fetching the data.we take some input fields and fetch the output fields from the table in general....
I want to convert a table storing in Name-Value pair data to relational form in SQL Server 2008. Source table Strings ID Type String 100 1 John 100 2 Milton 101 1 Johny 101 2 Gaddar Target required Customers ID FirstName LastName 100 John Milton 101 Johny Gaddar I am following the strategy given below, Populate the Customer t...
I'm still investigating issues I have with GC tuning (see prior question), which involves lots of reading and experimentation. Sun Java5+ JVMs attempt to automatically select the optimal GC strategy and parameters based on their environment, which is great, but I can't figure out how to query the running JVM to find out what those param...
I've used YSlow add in for Firefox and found it useful, does the new new google addin for Chrome give me anything extra? http://googleblog.blogspot.com/2009/12/faster-apps-for-faster-web-introducing.html ...
Given two arrays hashes and table, for each value in hashes I want to store the position of the element at the element's value's offset in the array table. Here is the naïve algorithm: def insert_n(table,hashes): for x in xrange(len(hashes)): table[hashes[x]]=x This is extremely slow. Psyco helps some here, but hardly. N...
I've been having it analyze my queries and pushing the recommendations for some time now. Are there any potential pitfalls with doing this? Would I be better of creating my own indexes by hand? ...