I am writing a client-side Swing application (graphical font designer) on Java 5. Recently, I am running into "java.lang.OutOfMemoryError: Java heap space" error because I am not being conservative on memory usage. The user can open unlimited number of files, and the program keeps the opened objects in the memory. After a quick research ...
I've been reading up on Linux's "swappiness" tuneable, which controls how aggressive the kernel is about swapping applications' memory to disk when they're not being used. If you Google the term, you get a lot of pages like this discussing the pros and cons. In a nutshell, the argument goes like this: If your swappiness is too low, i...
Anyone have any idea? And any open source sofware which also seens to perform this kind of functionality? ...
Oracle FAQ defines temp table space as follows: Temporary tablespaces are used to manage space for database sort operations and for storing global temporary tables. For example, if you join two large tables, and Oracle cannot do the sort in memory, space will be allocated in a temporary tablespace for doing the sort o...
We have recently migrated a large, high demand web application to Tomcat 5.5 from Tomcat 4 and have noticed some peculiar slowdown behavior that appears to be related to JVM pauses. In order to run our application and support increased load over time on Tomcat 4, many not so standard JVM parameters were set and tuned as per the below, a...
"We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil." (Donald Knuth). My SQL tables are unlikely to contain more than a few thousand rows each (and those are the big ones!). SQL Server Database Engine Tuning Advisor dismisses the amount of data as irrelevant. So I shouldn'...
I need to increase the max_allowed_packet param, to fit some theoretically very large items. If I set this param to say 10M, what price if any am I paying compared to setting it to 1M or 4M. Thanks for any input! Tomas ...
Coming from a java background, one of the things I am used to is telling the JVM what the maximum heap size should be. If the running program tries to swallow more than is allowed, and the garbage collector cannot free any more resources, then OutOfMemoryError is thrown and it all goes bang. So setting the maximum heap size is importan...
Are there any tuning knobs that one can apply for Oracle BPEL Process Manager? ...
Hi, Simple question, but I haven't found a good explanation on google. When using Set Statistics IO ON, the logical reads and scan count is provided in the message window of management studio. If I have: tblExample, scan count 5, logical reads 20 What does scan count signify? ...
I need lessons in memory management. I have an application that uses multiple views (around 10), some of these are attached to tab controller. Problem is that I'm using images (many images that I load from a web service). I'm facing the following issues. The memory keeps increasing when I scroll in the table view (why?) - I checked the...
Hello everyone, I found when I turn off (un-select) automatically detect proxies setting in Internet Options, my application (which involves a lot of Http based network communication) performance will boost a lot. Now I want to prove that performance issue is actually caused by automatically proxy detection. Any ideas from debugger o...
Sometime soon we will need to make schema changes to our production database. We need to minimize downtime for this effort, however, the ALTER TABLE statements are going to run for quite a while. Our largest tables have 150 million records, largest table file is 50G. All tables are InnoDB, and it was set up as one big data file (instead ...
how does the query optimizer determine estimated row size when we execute any query? ...
How do we insert data about 2 million rows into a oracle database table where we have many indexes on it? I know that one option is disabling index and then inserting the data. Can anyone tell me what r the other options? ...
I have a program I ported from C to Java. Both apps use quicksort to order some partitioned data (genomic coordinates). The Java version runs fast, but I'd like to get it closer to the C version. I am using the Sun JDK v6u14. Obviously I can't get parity with the C application, but I'd like to learn what I can do to eke out as much pe...
I am doing some tuning in a very large application. Is there a way to measure number of events fired in an application? For example using something in System.Diagnostics? Adding code inside events is NOT an acceptable solution due to the size of the application. There are profiling tools, but the fast and simple approach for me would b...
I'm runnning MySQL 5.0.45/ PHP Version 5.2.6 / CentOS with Plesk. I get occasionaly a burst of "Can't create a new thread (errno 12); if you are not out of available memory, you can consult the manual for a possible OS-dependent bug" Global memory is not the issue since I have about 620M free. Anyone know what could be the cause for t...
Given these two commands A: $ java -Xms10G -Xmx10G myjavacode input.txt B: $ java -Xms5G -Xmx5G myjavacode input.txt I have two questions: Since command A reserves more memory with its parameters, will A run faster than B? How do -Xmx and -Xms affect the running process and the output of my program? ...
See this screenshot from Firebug's Net tab: I know that: The time between 1 and 2 is the time taken by my app to generate the HTML and for the data to make its way to the browser. The time between 3 and 4 is the time taken by my JavaScript initialization code which runs on DOMContentLoaded. But what about the time between 2 and 3?...