I have a LAMP server with 256MB RAM (poor man's server in cloud). I have an app written to run on this machine. Currently people upload images and they go straight into mysql as BLOB. There are concerns that this might be very memory consuming operation and we move over it to simple plain files. Can some one tell me if these concerns a...
Hi, I'm having some performance issues when querying a table in a production database. While the query runs in 2.1 seconds in the test database (returning 8640 of 28 million records), at production, it takes 2.05 minutes (returning 8640 of 31 million records). I'm having a hard time to find the problem since I'm not an oracle expert. S...
Why is Eclipse so slow to load a file? I double click a file in the Project Explorer and it takes as long as 5 seconds before it appears as a new editor tab! I hear people complaining about Eclipse's speed but it hasn't been true for me -- everything else generally runs fine except for this. Computer has 8 procs at 2.8GHz and 16 gigs ...
I am using the App Engine Bulk loader (Python Runtime) to bulk upload entities to the data store. The data that i am uploading is stored in a proprietary format, so i have implemented by own connector (registerd it in bulkload_config.py) to convert it to the intermediate python dictionary. import google.appengine.ext.bulkload import con...
Hi we have a load balanced environment where same J2EE application is running on two VMWare based servers, hosted on same ESX Host. Hence, the OS/Platform/Hardware and everything else is same. Issue is that application deployed on one server responds faster than application deployed on the other server. The difference is response time is...
I have a cursor that selects all rows in a table, a little over 500,000 rows. Read a row from cursor, INSERT into other table, which has two indexes, neither unique, one numeric, one 'DATE' type. COMMIT. Read next row from Cursor, INSERT...until Cursor is empty. All my DATE column's values are the same, from a timestamp initialized at t...
Hi, I have a DTS package, which after running daily with no problems for a couple of years, has started to play up. Originally it was inserting data into a table which would then fire an insert trigger. The trigger used [inserted] to update three columns in the table. Usually, it was updating about 500,000 rows of inserted data. When t...
I run my project within VS and from time to time I run it with VS profiler. The question is how to detect the second case? The reason: I would like to trigger GUI events from program when profiling -- this way I would avoid manually clicking on widgets every time I do profiling. I am explaining this, because maybe is smarter way then d...
I have implemented an A* search algorithm for finding a shortest path between two states. Algorithm uses a hash-map for storing best known distances for visited states. And one hash-map for storing child-parent relationships needed for reconstruction of the shortest path. Here is the code. Implementation of the algorithm is generic (st...
We've a stored procedure that happens to build up some dynamic SQL and execute via a parametrised call to sp_executesql. Under normal conditions, this works wonderfully, and has made a large benefit in execution times for the procedure (~8 seconds to ~1 second), however, under some unknown conditions, something strange happens, and perf...
Hi, Well We have situation to decide now. I thought stackoverflow is best place to discuss. Background: We have 2 JVMs Enterprise Application server and one application deployed on each of them. we need to enable the business functionality invocation from one machine to other. Let assume one is client and another is server. Now from ...
I am querying database with follwing query. This query takes 21 seconds to execute. I have check it by explain query. I have index on fields groupId , batchId separately. EXPLAIN SELECT message, sentOn, maskId, isDndCheck, contentType FROM sms_histories WHERE groupId = 1750 GROUP BY batchId ORDER BY batchId DESC LIMIT 0 , 1 I am gett...
I'm working with a huge table which has 250+ million rows. The schema is simple. CREATE TABLE MyTable ( id BIGINT PRIMARY KEY AUTO_INCREMENT, oid INT NOT NULL, long1 BIGINT NOT NULL, str1 VARCHAR(30) DEFAULT NULL, str2 VARCHAR(30) DEFAULT NULL, str2 VARCHAR(200) DEFAULT NULL, str4...
I have a query that has appropriate indexes and is shown in the query plan with an estimated subtree cost of circa 1.5. The plan shows an Index Seek, followed by Key Lookup - which is fine for a query expected to return 1 row from a set of between 5 and 20 rows (i.e. the Index Seek should find between 5 and 20 rows, and after 5 - 20 Key...
Hi, i'm writing a C# class to perform 2D separable convolution using integers to obtain better performance than double counterpart. The problem is that i don't obtain a real performance gain. This is the X filter code (it is valid both for int and double cases): foreach (pixel) { int value = 0; for (int k = 0; k < filterO...
In old versions of tomcat (like 3.2) you can find the recomendation to serve static content in a apache web server and leave the dynamic content to the tomcat itself. At the new versions of the tomcat docs you cannot find any reference to this practice even at the mod_jk configuration tutorial. So I am wondering. Is still true that tom...
I’m running some performance tests on an ASP.NET MVC application. I see a high contention rate and the number of threads increasing overtime. I believe the two to be related, as threads are blocked new threads are created by the thread pool to handle incoming requests. I believe this in turn is making the contention worse (i.e. more thre...
I'm currently profiling an ASP.NET MVC application. We're seeing that the "% Time in RT Checks" counter is very high. I understand this means we are passing a lot of time in CAS checks, but I'm having difficultly pin pointing what code is making this CAS checks. We do very little native interop, so it does come from that. What other fram...
How does: dict = {} if key not in dict: dict[key] = foo Compare to: try: dict[key] except KeyError: dict[key] = foo ie, is the look up of a key in anyway faster than the linear search through dict.keys(), that I assume the first form will do? ...
We were having a performance issue in a C# while loop. The loop was super slow doing only one simple math calc. Turns out that parmIn can be a huge number anywhere from 999999999 to MaxInt. We hadn't anticipated the giant value of parmIn. We have fixed our code using a different methodology. The loop, coded for simplicity below, d...