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• Why can't decimal numbers be represented exactly in binary?

  - by Barry Brown

  There have been several questions posted to SO about floating-point representation. For example, the decimal number 0.1 doesn't have an exact binary representation, so it's dangerous to use the == operator to compare it to another floating-point number. I understand the principles behind floating-point representation. What I don't understand is why, from a mathematical perspective, are the numbers to the right of the decimal point any more "special" that the ones to the left? For example, the number 61.0 has an exact binary representation because the integral portion of any number is always exact. But the number 6.10 is not exact. All I did was move the decimal one place and suddenly I've gone from Exactopia to Inexactville. Mathematically, there should be no intrinsic difference between the two numbers -- they're just numbers. By contrast, if I move the decimal one place in the other direction to produce the number 610, I'm still in Exactopia. I can keep going in that direction (6100, 610000000, 610000000000000) and they're still exact, exact, exact. But as soon as the decimal crosses some threshold, the numbers are no longer exact. What's going on? Edit: to clarify, I want to stay away from discussion about industry-standard representations, such as IEEE, and stick with what I believe is the mathematically "pure" way. In base 10, the positional values are: ... 1000 100 10 1 1/10 1/100 ... In binary, they would be: ... 8 4 2 1 1/2 1/4 1/8 ... There are also no arbitrary limits placed on these numbers. The positions increase indefinitely to the left and to the right.

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• Why have or haven't you moved to ASP.NET MVC yet?

  - by Jason

  I find myself on the edge of trying out ASP.NET MVC but there is still "something" holding me back. Are you still waiting to try it, and if so, why? If you finally decided to use it, what helped you get over your hesitation? I'm not worried about it from a technical point of view; I know the pros and cons of web forms vs MVC. My concerns are more on the practical side. Will Microsoft continue to support ASP.NET MVC if they don't reach some critical threshold of developers/customers using it? Are customers willing to try ASP.NET MVC? Have you had to convince a customer to use it? How did that go? Are there major sites using ASP.NET MVC (besides SO)? Could you provide links if you have them? Did you try ASP.NET MVC and found yourself regretting it? If so, what do you regret? If you have any other concerns preventing you from using MVC.NET, what are they? If you had concerns but felt they were addressed and now use MVC.NET, could you list them as well? Thanks

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• why does entity framework+mysql provider enumeration returns partial results with no exceptions

  - by Freddy Rios

  I'm trying to make sense of a situation I have using entity framework on .net 3.5 sp1 + MySQL 6.1.2.0 as the provider. It involves the following code: Response.Write("Products: " + plist.Count() + "<br />"); var total = 0; foreach (var p in plist) { //... some actions total++; //... other actions } Response.Write("Total Products Checked: " + total + "<br />"); Basically the total products is varying on each run, and it isn't matching the full total in plist. Its varies widely, from ~ 1/5th to half. There isn't any control flow code inside the foreach i.e. no break, continue, try/catch, conditions around total++, anything that could affect the count. As confirmation, there are other totals captured inside the loop related to the actions, and those match the lower and higher total runs. I don't find any reason to the above, other than something in entity framework or the mysql provider that causes it to end the foreach when retrieving an item. The body of the foreach can have some good variation in time, as the actions involve file & network access, my best shot at the time is that when the .net code takes beyond certain threshold there is some type of timeout in the underlying framework/provider and instead of causing an exception it is silently reporting no more items for enumeration. Can anyone give some light in the above scenario and/or confirm if the entity framework/mysql provider has the above behavior? Update: I can't reproduce the behavior by using Thread.Sleep in a simple foreach in a test project, not sure where else to look for this weird behavior :(.

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• How to track the touch vector?

  - by mystify

  I need to calculate the direction of dragging a touch, to determine if the user is dragging up the screen, or down the screen. Actually pretty simple, right? But: 1) Finger goes down, you get -touchesBegan:withEvent: called 2) Must wait until finger moves, and -touchesMoved:withEvent: gets called 3) Problem: At this point it's dangerous to tell if the user did drag up or down. My thoughts: Check the time and accumulate calculates vectors until it's secure to tell the direction of touch. Easy? No. Think about it: What if the user holds the finger down for 5 minutes on the same spot, but THEN decides to move up or down? BANG! Your code would fail, because it tried to determine the direction of touch when the finger didn't move really. Problem 2: When the finger goes down and stays at the same spot for a few seconds because the user is a bit in the wind and thinks about what to do now, you'll get a lot of -touchesMoved:withEvent: calls very likely, but with very minor changes in touch location. So my next thought: Do the accumulation in -touchesMoved:withEvent:, but only if a certain threshold of movement has been exceeded. I bet you have some better concepts in place?

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• does entity framework or mysql provider swallows timeout exceptions on enumeration of result?!

  - by Freddy Rios

  I'm trying to make sense of a situation I have using entity framework on .net 3.5 sp1 + MySQL 6.1.2.0 as the provider. It involves the following code: Response.Write("Products: " + plist.Count() + "<br />"); var total = 0; foreach (var p in plist) { //... some actions total++; //... other actions } Response.Write("Total Products Checked: " + total + "<br />"); Basically the total products is varying on each run, and it isn't matching the full total in plist. Its varies widely, from ~ 1/5th to half. There isn't any control flow code inside the foreach i.e. no break, continue, try/catch, conditions around total++, anything that could affect the count. As confirmation, there are other totals captured inside the loop related to the actions, and those match the lower and higher total runs. I don't find any reason to the above, other than something in entity framework or the mysql provider that causes it to end the foreach when retrieving an item. The body of the foreach can have some good variation in time, as the actions involve file & network access, my best shot at the time is that when it takes beyond certain threshold there is some type of timeout in the underlying framework/provider and instead of causing an exception it is silently reporting no more items for enumeration. Can anyone give some light in the above scenario and/or confirm if the entity framework/mysql provider has the above behavior?

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• .NET Remoting: Getting underlying socket?

  - by Alan

  Hi, I'm writing a light remoting app to assist in debugging a problem with remoting communication. This app mimics much of what a larger application does: Periodically sends a heartbeat to another peer application, and periodically verifies that a heartbeat has been received within some time threshold. What we're seeing is in our big application, the heartbeats seem to get dropped. One peer will go for long periods of time without seeing heartbeats from another peer, until the peer that is "dead" is restarted. The big application is responsive in all other ways. We believe it has something to do with the network setup. We were able to repro the problem locally, and fixed it by making some configuration changes to our test environment. To help our customer diagnose the issue, the mini-remoting app needs to log as much information as possible. So, is there a way to get the underlying socket for the remoting connection? I'm aware that I could write a custom sink for this, but I'd like to keep the actual remoting process as close to what is implemented in the big app as possible. Also as an aside, any ideas why the big-app might be "dropping" heartbeats?

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• How to generate a monotone MART ROC in R?

  - by user1521587

  I am using R and applying MART (Alg. for multiple additive regression trees) on a training set to build prediction models. When I look at the ROC curve, it is not monotone. I would be grateful if someone can help me with how I should fix this. I am guessing the issue is that initially, MART generates n trees and if these trees are not the same for all the models I am building, the results will not be comparable. Here are the steps I take: 1) Fix the false-negative cost, c_fn. Let cost = c(0, 1, c_fn, 0). 2) use the following line to build the mart model: mart(x, y, lx, martmode='class', niter=2000, cost.mtx=cost) where x is the matrix of training set variables, y is the observation matrix, lx is the matrix which specifies which of the variables in x is numerical, which one categorical. 3) I predict the test set observations using the mart model found in step 2 using this line: y_pred = martpred(x_test, probs=T) 4) I compute the false-positive and false-negative errors as follows: t = 1/(1+c_fn) %threshold based on Bayes optimal rule where c_fp=1 and c_fn. p_0 = length(which(y_test==1))/dim(y_test)[1] p_01 = sum(1*(y_pred[,2]t & y_test==0))/dim(y_test)[1] p_11 = sum(1*(y_pred[,2]t & y_test==1))/dim(y_test)[1] p_fp = p_01/(1-p_0) p_tp = p_11/p_0 5) repeat step 1-4 for a new false-negative cost.

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• How to alter Postgres table data based on its contents?

  - by williamjones

  This is probably a super simple question, but I'm struggling to come up with the right keywords to find it on Google. I have a Postgres table that has among its contents a column of type text named content_type. That stores what type of entry is stored in that row. There are only about 5 different types, and I decided I want to change one of them to display as something else in my application (I had been directly displaying these). It struck me that it's funny that my view is being dictated by my database model, and I decided I would convert the types being stored in my database as strings into integers, and enumerate the possible types in my application with constants that convert them into their display names. That way, if I ever got the urge to change any category names again, I could just change it with one alteration of a constant. I also have the hunch that storing integers might be somewhat more efficient than storing text in the database. First, a quick threshold question of, is this a good idea? Any feedback or anything I missed? Second, and my main question, what's the Postgres command I could enter to make an alteration like this? I'm thinking I could start by renaming the old content_type column to old_content_type and then creating a new integer column content_type. However, what command would look at a row's old_content_type and fill in the new content_type column based off of that?

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• c++ overloading delete, retrieve size

  - by user300713

  Hi, I am currently writing a small custom memory Allocator in c++, and want to use it together with operator overloading of new/delete. Anyways, my memory Allocator basicall checks if the requested memory is over a certain threshold, and if so uses malloc to allocate the requested memory chunk. Otherwise the memory will be provided by some fixedPool allocators. that generally works, but for my deallocation function looks like this: void MemoryManager::deallocate(void * _ptr, size_t _size){ if(_size heapThreshold) deallocHeap(_ptr); else deallocFixedPool(_ptr, _size); } so I need to provide the size of the chunk pointed to, to deallocate from the right place. No the problem is that the delete keyword does not provide any hint on the size of the deleted chunk, so I would need something like this: void operator delete(void * _ptr, size_t _size){ MemoryManager::deallocate(_ptr, _size); } But as far as I can see, there is no way to determine the size inside the delete operator.- If I want to keep things the way it is right now, would I have to save the size of the memory chunks myself? Any ideas on how to solve this are welcome! Thanks!

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• What is the fastest way to insert 100 000 records from one database to another?

  - by Pentium10

  I have a mobile application. My client has a large data set ~100.000 records. It's updated frequently. When we sync we need to copy from one database to another. I have attached the second database to the main, and run an insert into table select * from sync.table. This is extremely slow, it takes about 10 minutes I think. I noticed that the journal file gets increased step by step. How can I speed this up? EDITED 1 I have indexes off, and I have journal off. Using insert into table select * from sync.table it still takes 10 minutes. EDITED 2 If I run a query like select id,invitem,invid,cost from inventory where itemtype = 1 order by invitem limit 50 it takes 15-20 seconds. The table schema is: CREATE TABLE inventory ('id' INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, 'serverid' INTEGER NOT NULL DEFAULT 0, 'itemtype' INTEGER NOT NULL DEFAULT 0, 'invitem' VARCHAR, 'instock' FLOAT NOT NULL DEFAULT 0, 'cost' FLOAT NOT NULL DEFAULT 0, 'invid' VARCHAR, 'categoryid' INTEGER DEFAULT 0, 'pdacategoryid' INTEGER DEFAULT 0, 'notes' VARCHAR, 'threshold' INTEGER NOT NULL DEFAULT 0, 'ordered' INTEGER NOT NULL DEFAULT 0, 'supplier' VARCHAR, 'markup' FLOAT NOT NULL DEFAULT 0, 'taxfree' INTEGER NOT NULL DEFAULT 0, 'dirty' INTEGER NOT NULL DEFAULT 1, 'username' VARCHAR, 'version' INTEGER NOT NULL DEFAULT 15 ) Indexes are created like CREATE INDEX idx_inventory_categoryid ON inventory (pdacategoryid); CREATE INDEX idx_inventory_invitem ON inventory (invitem); CREATE INDEX idx_inventory_itemtype ON inventory (itemtype); I am wondering, the insert into ... select * from isn't the fastest built-in way to do massive data copy? EDITED 3 SQLite is serverless, so please stop voting a particular answer, because that is not the answer I'm sure.

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• Quickly generate junk data of certain size in Javascript

  - by user1357607

  I am writing an upload speed test in Javascript. I am using Jquery (and Ajax) to send chunks of data to a server in order to time how long it takes to get a response. This should, in theory give an estimation, of the upload speed. Of course to cater for different bandwidths of the user I sequentially upload larger and larger amounts of junk data until a threshold duration is reached. Currently I generate the junk data using the following function, however, it is very slow when generation megabytes of data. function generate_random_data(size){ var chars = "abcdefghijklmnopqrstuvwxyz"; var random_data = ""; for (var i = 0; i < size; i++){ var random_num = Math.floor(Math.random() * char.length); random_data = random_data + chars.substring(random_num,random_num+1); } return random_data; Really all I am doing is generating a chunk of bytes to send to the server, however, this is the only way I could find out how in Javascript. Any help would be appreciated.

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• How to efficiently use LOCK_ESCALATION mssql 2008

  - by Avias

  I'm currently having troubles with frequent deadlocks with a specific user table in MS SQL 2008. Here are some facts about this particular table: Has a large amount of rows (1 to 2 million) All the indexes used on this table only has "use row lock" ticked on its option rows are frequently updated by multiple transactions but are unique (e.g. probably a thousand or more update statements are executed to different unique rows every hour) the table does not use partitions. Upon checking the table on sys.tables, I found that the lock_escalation is set to TABLE I'm very tempted to turn the lock_escalation for this table to DISABLE but I'm not really sure what side effect this would incur. From What I understand, using DISABLE will minimize escalating locks to TABLE level which if combined with the row lock settings of the indexes should theoretically minimize the deadlocks I am encountering.. From what I have read in Determining threshold for lock escalation it seems that locking automatically escalates when a single transaction fetches 5000 rows.. What does a single transaction mean in this sense? A single session/connection getting 5000 rows thru individual update/select statements? Or is it a single sql update/select statement that fetches 5000 or more rows? Any insight is appreciated, btw, n00b DBA here Thanks

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• SQL SERVER – Introduction to Wait Stats and Wait Types – Wait Type – Day 1 of 28

  - by pinaldave

  I have been working a lot on Wait Stats and Wait Types recently. Last Year, I requested blog readers to send me their respective server’s wait stats. I appreciate their kind response as I have received  Wait stats from my readers. I took each of the results and carefully analyzed them. I provided necessary feedback to the person who sent me his wait stats and wait types. Based on the feedbacks I got, many of the readers have tuned their server. After a while I got further feedbacks on my recommendations and again, I collected wait stats. I recorded the wait stats and my recommendations and did further research. At some point at time, there were more than 10 different round trips of the recommendations and suggestions. Finally, after six month of working my hands on performance tuning, I have collected some real world wisdom because of this. Now I plan to share my findings with all of you over here. Before anything else, please note that all of these are based on my personal observations and opinions. They may or may not match the theory available at other places. Some of the suggestions may not match your situation. Remember, every server is different and consequently, there is more than one solution to a particular problem. However, this series is written with kept wait stats in mind. While I was working on various performance tuning consultations, I did many more things than just tuning wait stats. Today we will discuss how to capture the wait stats. I use the script diagnostic script created by my friend and SQL Server Expert Glenn Berry to collect wait stats. Here is the script to collect the wait stats: -- Isolate top waits for server instance since last restart or statistics clear WITH Waits AS (SELECT wait_type, wait_time_ms / 1000. AS wait_time_s, 100. * wait_time_ms / SUM(wait_time_ms) OVER() AS pct, ROW_NUMBER() OVER(ORDER BY wait_time_ms DESC) AS rn FROM sys.dm_os_wait_stats WHERE wait_type NOT IN ('CLR_SEMAPHORE','LAZYWRITER_SLEEP','RESOURCE_QUEUE','SLEEP_TASK' ,'SLEEP_SYSTEMTASK','SQLTRACE_BUFFER_FLUSH','WAITFOR', 'LOGMGR_QUEUE','CHECKPOINT_QUEUE' ,'REQUEST_FOR_DEADLOCK_SEARCH','XE_TIMER_EVENT','BROKER_TO_FLUSH','BROKER_TASK_STOP','CLR_MANUAL_EVENT' ,'CLR_AUTO_EVENT','DISPATCHER_QUEUE_SEMAPHORE', 'FT_IFTS_SCHEDULER_IDLE_WAIT' ,'XE_DISPATCHER_WAIT', 'XE_DISPATCHER_JOIN', 'SQLTRACE_INCREMENTAL_FLUSH_SLEEP')) SELECT W1.wait_type, CAST(W1.wait_time_s AS DECIMAL(12, 2)) AS wait_time_s, CAST(W1.pct AS DECIMAL(12, 2)) AS pct, CAST(SUM(W2.pct) AS DECIMAL(12, 2)) AS running_pct FROM Waits AS W1 INNER JOIN Waits AS W2 ON W2.rn <= W1.rn GROUP BY W1.rn, W1.wait_type, W1.wait_time_s, W1.pct HAVING SUM(W2.pct) - W1.pct < 99 OPTION (RECOMPILE); -- percentage threshold GO This script uses Dynamic Management View sys.dm_os_wait_stats to collect the wait stats. It omits the system-related wait stats which are not useful to diagnose performance-related bottleneck. Additionally, not OPTION (RECOMPILE) at the end of the DMV will ensure that every time the query runs, it retrieves new data and not the cached data. This dynamic management view collects all the information since the time when the SQL Server services have been restarted. You can also manually clear the wait stats using the following command: DBCC SQLPERF('sys.dm_os_wait_stats', CLEAR); Once the wait stats are collected, we can start analysis them and try to see what is causing any particular wait stats to achieve higher percentages than the others. Many waits stats are related to one another. When the CPU pressure is high, all the CPU-related wait stats show up on top. But when that is fixed, all the wait stats related to the CPU start showing reasonable percentages. It is difficult to have a sure solution, but there are good indications and good suggestions on how to solve this. I will keep this blog post updated as I will post more details about wait stats and how I reduce them. The reference to Book On Line is over here. Of course, I have selected February to run this Wait Stats series. I am already cheating by having the smallest month to run this series. :) Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: DMV, Pinal Dave, PostADay, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• How To Clear An Alert - Part 2

  - by werner.de.gruyter

  There were some interesting comments and remarks on the original posting, so I decided to do a follow-up and address some of the issues that got raised... Handling Metric Errors First of all, there is a significant difference between an 'error' and an 'alert'. An 'alert' is the violation of a condition (a threshold) specified for a given metric. That means that the Agent is collecting and gathering the data for the metric, but there is a situation that requires the attention of an administrator. An 'error' on the other hand however, is a failure to collect metric data: The Agent is throwing the error because it cannot determine the value for the metric Whereas the 'alert' guarantees continuity of the metric data, an 'error' signals a big unknown. And the unknown aspect of all this is what makes an error a lot more serious than a regular alert: If you don't know what the current state of affairs is, there could be some serious issues brewing that nobody is aware of... The life-cycle of a Metric Error Clearing a metric error is pretty much the same workflow as a metric 'alert': The Agent signals the error after it failed to execute the metric The error is uploaded to the OMS/repository, where it becomes visible in the Console The error will remain active until the Agent is able to execute the metric successfully. Even though the metric is still getting scheduled and executed on a regular basis, the error will remain outstanding as long as the Agent is not capable of executing the metric correctly Knowing this, the way to fix the metric error should be obvious: Take the 'problem' away, and as soon as the metric is executed again (based on the frequency of the metric), the error will go away. The same tricks used to clear alerts can be used here too: Wait for the next scheduled execution. For those metrics that are executed regularly (like every 15 minutes or so), it's just a matter of waiting those minutes to see the updates. The 'Reevaluate Alert' button can be used to force a re-execution of the metric. In case a metric is executed once a day, this will be a better way to make sure that the underlying problem has been solved. And if it has been, the metric error will be removed, and the regular data points will be uploaded to the repository. And just in case you have to 'force' the issue a little: If you disable and re-enable a metric, it will get re-scheduled. And that means a new metric execution, and an update of the (hopefully) fixed problem. Database server-generated alerts and problem checkers There are various ways the Agent can collect metric data: Via a script or a SQL statement, reading a log file, getting a value from an SNMP OID or listening for SNMP traps or via the DBMS_SERVER_ALERTS mechanism of an Oracle database. For those alert which are generated by the database (like tablespace metrics for 10g and above databases), the Agent just 'waits' for the database to report any new findings. If the Agent has lost the current state of the server-side metrics (due to an incomplete recovery after a disaster, or after an improper use of the 'emctl clearstate' command), the Agent might be still aware of an alert that the database no longer has (or vice versa). The same goes for 'problem checker' alerts: Those metrics that only report data if there is a problem (like the 'invalid objects' metric) will also have a problem if the Agent state has been tampered with (again, the incomplete recovery, and after improper use of 'emctl clearstate' are the two main causes for this). The best way to deal with these kinds of mismatches, is to simple disable and re-enable the metric again: The disabling will clear the state of the metric, and the re-enabling will force a re-execution of the metric, so the new and updated results can get uploaded to the repository. Starting 10gR5, the Agent performs additional checks and verifications after each restart of the Agent and/or each state change of the database (shutdown/startup or failover in case of DataGuard) to catch these kinds of mismatches.

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• To sample or not to sample...

  - by [email protected]

  Ideally, we would know the exact answer to every question. How many people support presidential candidate A vs. B? How many people suffer from H1N1 in a given state? Does this batch of manufactured widgets have any defective parts? Knowing exact answers is expensive in terms of time and money and, in most cases, is impractical if not impossible. Consider asking every person in a region for their candidate preference, testing every person with flu symptoms for H1N1 (assuming every person reported when they had flu symptoms), or destructively testing widgets to determine if they are "good" (leaving no product to sell). Knowing exact answers, fortunately, isn't necessary or even useful in many situations. Understanding the direction of a trend or statistically significant results may be sufficient to answer the underlying question: who is likely to win the election, have we likely reached a critical threshold for flu, or is this batch of widgets good enough to ship? Statistics help us to answer these questions with a certain degree of confidence. This focuses on how we collect data. In data mining, we focus on the use of data, that is data that has already been collected. In some cases, we may have all the data (all purchases made by all customers), in others the data may have been collected using sampling (voters, their demographics and candidate choice). Building data mining models on all of your data can be expensive in terms of time and hardware resources. Consider a company with 40 million customers. Do we need to mine all 40 million customers to get useful data mining models? The quality of models built on all data may be no better than models built on a relatively small sample. Determining how much is a reasonable amount of data involves experimentation. When starting the model building process on large datasets, it is often more efficient to begin with a small sample, perhaps 1000 - 10,000 cases (records) depending on the algorithm, source data, and hardware. This allows you to see quickly what issues might arise with choice of algorithm, algorithm settings, data quality, and need for further data preparation. Instead of waiting for a model on a large dataset to build only to find that the results don't meet expectations, once you are satisfied with the results on the initial sample, you can  take a larger sample to see if model quality improves, and to get a sense of how the algorithm scales to the particular dataset. If model accuracy or quality continues to improve, consider increasing the sample size. Sampling in data mining is also used to produce a held-aside or test dataset for assessing classification and regression model accuracy. Here, we reserve some of the build data (data that includes known target values) to be used for an honest estimate of model error using data the model has not seen before. This sampling transformation is often called a split because the build data is split into two randomly selected sets, often with 60% of the records being used for model building and 40% for testing. Sampling must be performed with care, as it can adversely affect model quality and usability. Even a truly random sample doesn't guarantee that all values are represented in a given attribute. This is particularly troublesome when the attribute with omitted values is the target. A predictive model that has not seen any examples for a particular target value can never predict that target value! For other attributes, values may consist of a single value (a constant attribute) or all unique values (an identifier attribute), each of which may be excluded during mining. Values from categorical predictor attributes that didn't appear in the training data are not used when testing or scoring datasets. In subsequent posts, we'll talk about three sampling techniques using Oracle Database: simple random sampling without replacement, stratified sampling, and simple random sampling with replacement.

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• Algorithm to Find the Aggregate Mass of "Granola Bar"-Like Structures?

  - by Stuart Robbins

  I'm a planetary science researcher and one project I'm working on is N-body simulations of Saturn's rings. The goal of this particular study is to watch as particles clump together under their own self-gravity and measure the aggregate mass of the clumps versus the mean velocity of all particles in the cell. We're trying to figure out if this can explain some observations made by the Cassini spacecraft during the Saturnian summer solstice when large structures were seen casting shadows on the nearly edge-on rings. Below is a screenshot of what any given timestep looks like. (Each particle is 2 m in diameter and the simulation cell itself is around 700 m across.) The code I'm using already spits out the mean velocity at every timestep. What I need to do is figure out a way to determine the mass of particles in the clumps and NOT the stray particles between them. I know every particle's position, mass, size, etc., but I don't know easily that, say, particles 30,000-40,000 along with 102,000-105,000 make up one strand that to the human eye is obvious. So, the algorithm I need to write would need to be a code with as few user-entered parameters as possible (for replicability and objectivity) that would go through all the particle positions, figure out what particles belong to clumps, and then calculate the mass. It would be great if it could do it for "each" clump/strand as opposed to everything over the cell, but I don't think I actually need it to separate them out. The only thing I was thinking of was doing some sort of N2 distance calculation where I'd calculate the distance between every particle and if, say, the closest 100 particles were within a certain distance, then that particle would be considered part of a cluster. But that seems pretty sloppy and I was hoping that you CS folks and programmers might know of a more elegant solution? Edited with My Solution: What I did was to take a sort of nearest-neighbor / cluster approach and do the quick-n-dirty N2 implementation first. So, take every particle, calculate distance to all other particles, and the threshold for in a cluster or not was whether there were N particles within d distance (two parameters that have to be set a priori, unfortunately, but as was said by some responses/comments, I wasn't going to get away with not having some of those). I then sped it up by not sorting distances but simply doing an order N search and increment a counter for the particles within d, and that sped stuff up by a factor of 6. Then I added a "stupid programmer's tree" (because I know next to nothing about tree codes). I divide up the simulation cell into a set number of grids (best results when grid size ˜7 d) where the main grid lines up with the cell, one grid is offset by half in x and y, and the other two are offset by 1/4 in ±x and ±y. The code then divides particles into the grids, then each particle N only has to have distances calculated to the other particles in that cell. Theoretically, if this were a real tree, I should get order N*log(N) as opposed to N2 speeds. I got somewhere between the two, where for a 50,000-particle sub-set I got a 17x increase in speed, and for a 150,000-particle cell, I got a 38x increase in speed. 12 seconds for the first, 53 seconds for the second, 460 seconds for a 500,000-particle cell. Those are comparable speeds to how long the code takes to run the simulation 1 timestep forward, so that's reasonable at this point. Oh -- and it's fully threaded, so it'll take as many processors as I can throw at it.

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• SQL SERVER – Speed Up! – Parallel Processes and Unparalleled Performance – TechEd 2012 India

  - by pinaldave

  TechEd India 2012 is just around the corner and I will be presenting there on two different session. SQL Server Performance Tuning is a very challenging subject that requires expertise in Database Administration and Database Development. I always have enjoyed talking about SQL Server Performance tuning subject. Just like doctors I like to call my every attempt to improve the performance of SQL Server queries and database server as a practice too. I have been working with SQL Server for more than 8 years and I believe that many of the performance tuning concept I have mastered. However, performance tuning is not a simple subject. However there are occasions when I feel stumped, there are occasional when I am not sure what should be the next step. When I face situation where I cannot figure things out easily, it makes me most happy because I clearly see this as a learning opportunity. I have been presenting in TechEd India for last three years. This is my fourth time opportunity to present a technical session on SQL Server. Just like every other year, I decided to present something different, something which I have spend years of learning. This time, I am going to present about parallel processes. It is widely believed that more the CPU will improve performance of the server. It is true in many cases. However, there are cases when limiting the CPU usages have improved overall health of the server. I will be presenting on the subject of Parallel Processes and its effects. I have spent more than a year working on this subject only. After working on various queries on multi-CPU systems I have personally learned few things. In coming TechEd session, I am going to share my experience with parallel processes and performance tuning. Session Details Title: Speed Up! – Parallel Processes and Unparalleled Performance (Add to Calendar) Abstract: “More CPU More Performance” – A  very common understanding is that usage of multiple CPUs can improve the performance of the query. To get maximum performance out of any query – one has to master various aspects of the parallel processes. In this deep dive session, we will explore this complex subject with a very simple interactive demo. An attendee will walk away with proper understanding of CX_PACKET wait types, MAXDOP, parallelism threshold and various other concepts. Date and Time: March 23, 2012, 12:15 to 13:15 Location: Hotel Lalit Ashok - Kumara Krupa High Grounds, Bengaluru – 560001, Karnataka, India. Add to Calendar Please submit your questions in the comments area and I will be for sure discussing them during my session. If I pick your question to discuss during my session, here is your gift I commit right now – SQL Server Interview Questions and Answers Book. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology Tagged: TechEd, TechEdIn

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• links for 2010-12-08

  - by Bob Rhubart

  What's a data architect? A comic dialog by one who knows: Oracle ACE Director Lewis Cunningham. Webcast: Oracle Business Intelligence Forum - December 15, 2010 at 9:00 am PT "The Oracle Business Intelligence Online Forum is a half-day virtual event that offers you a unique opportunity to see, in one place, the full portfolio of Oracle’s Business Intelligence (BI) offerings, and to learn what sets Oracle apart from the rest. Hear Oracle executives and industry analyst, Howard Dresner, present the current state of Business Intelligence, along with a series of customers who will share their case studies of putting analytics in action." Oracle Rolls Out Private Cloud Architecture And World-Record Transaction Performance | Forrester Blogs "Exadata has been dealt with extensively in other venues, both inside Forrester and externally, and appears to deliver the goods for I&O groups who require efficient consolidation and maximum performance from an Oracle database environment." -- Richard Fichera, Forrester Seven ways to get things started: Java EE Startup Classes with GlassFish and WebLogic "This is a blog about a topic that I realy don't like. But it comes across my ways over and over again and it's no doubt that you need it from time to time. Enough reasons for me to collect some information about it and publish it for your reference. I am talking about Startup-/Shutdown classes with Java EE applications or servers." -- Oracle ACE Director Markus "@myfear" Eisele." Monitoring Undelivered Messages in BPEL in SOA 10g (Antony Reynolds' Blog) "I am currently working with a client that wants to know how many undelivered messages they have, and if it reaches a certain threshold then they wants to alert the operator. To do this they plan on using the Enterprise Manager alert functions, but first they needs to know how many undelivered instances are out there." SOA author Antony Reynolds VirtualBox Appliances for Developers "Developers can simply download a few files, assemble them with a script , and then import and run the resulting pre-built VM in VirtualBox. This makes starting with these technologies even easier. Each appliance contains some Hands-On-Labs to start learning." -- Peter Paul van de Beek Oracle UCM 11g Remote Intradoc Client (RIDC) Integration with Oracle ADF 11g "It's great we have out of the box WebCenter ADF task flows for document management in UCM. However, for complete business scenario implementations, usually it's not enough and we need to manage Content Repository programmatically. This can be achieved through Remote Intradoc Client (RIDC) API. It's quite hard to find any practical information about this API, but I managed to get code for UCM folder creation/removal and folder information." -- Oracle ACE Director Andrejus Baranovskis Interview with Java Champion Matjaz B. Juric on Cloud Computing, SOA, and Java EE 6 "Matjaz Juric of Slovenia, head of the Cloud Computing and SOA Competence Centre at the University of Maribor, and professor at the University of Ljubljana, shares insights about cloud computing, SOA and Java EE 6." White Paper: Oracle Complex Event Processing High Availability "This whitepaper describes the high availability (HA) solutions available in Oracle CEP 11g Release 1 Patch Set 2 and  presents the results of a benchmark study demonstrating the performance of the Oracle CEP HA solutions."

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• Taking Your Business Scorecard Golfing

  - by tobyehatch

  Our workplace world is definitely changing. Not only are we taking work home, but we are working during odd hours in some very strange places.  I had the pleasure of interviewing Jacques Vigeant, Product Strategy Manager for Oracle Business Intelligence and Enterprise Performance Management, on a Podcast, and he enlightened me about how our mobile devices and business scorecards are enabling us to be more accountable and keep a watchful eye on business – even while on the golf course.Business scorecards have been around for many years - so I asked Jacques if he felt they had changed significantly due to technology. His answer was, “Yes, and no.”  Jacques agreed that scorecard enthusiasts are still passionate about executing the company strategy and monitoring Key Performance Indicators (KPIs), but scorecards and Business Intelligence (BI) as a whole have changed.  He explained that five to six years ago, people did BI work at the office and, for the most part, disconnected from their computer and workplace when they went home – with the exception of checking email and making a phone call or two. But now, that is no longer the case. People are virtually always connected with work and, more importantly, expect their BI and scorecards to be ‘always on,’ regardless of whether they are at their desk or somewhere else.Basically, the BI paradigm has changed from a 'pull' model, where employees are at their desks querying or pulling information from the system, to a 'push' model where employees expect their BI and scorecard systems to reach out (or push information) to them when there is something of note to learn or something on which they need to take action. I found this very interesting. However mobile devices do have their limitations with respect to screen sizes – does it really make sense to look at your strategy/scorecard on tiny devices? What kind of scorecard activities can you really expect to be able to do? Jacques’ answer was very logical. “When you think of a scorecard, it is really comprised of an organization of KPIs that are aligned with the strategic objectives of your company. KPIs are the heart of how you will execute your strategy. So, if you decompose that a little more, each KPI is well defined with the thresholds that you should keep an eye on and who is responsible for them. When we talk about scorecarding on a phone, we aren’t talking about surfing the strategy and exploring the strategy map like we do on the desktop. In a scorecarding context, we use the phone more as an alerting mechanism or simple monitoring device for your KPIs.”Jacques gave a great example of an inventory manager who took part of an afternoon off to go golfing before winter finally hit, and while on the front nine holes, his phone vibrated. His scorecard was alerting him that the inventory levels for one of the products was below some threshold that he had set.  From his phone, he had set up three options within Oracle Scorecard and Strategy Management (OSSM) for this type of situation:  1. Contact the warehouse manager directly by phone and work it out (standard phone function)  2. Tap/hold the KPI and add an annotation to the KPI in OSSM using the dictation capabilities of the phone and deal with it more fully when he gets back to the office  3. Tap/hold the KPI and invoke a business process from OSSM to transfer product from another warehouse with higher stock levels to the one that needs it  Being on a phone should still give you options to quickly deal with situations as needed, but mobile phones are not designed for nor should try to replicate the full desktop experience. We covered other interesting subjects in the interview, including how Oracle is keeping pace with mobile innovation and new devices such as Google Glasses, Galaxy Gear, Pebble Watches and more, and how Oracle is handling mobile security– which is great news for our mobile workforce. To listen to the entire Podcast, click here.To learn more about Oracle Scorecard and Strategy Management, click here.

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• SQL SERVER – #TechEdIn – Presenting Tomorrow on Speed Up! – Parallel Processes and Unparalleled Performance at TechEd India 2012

  - by pinaldave

  Performance tuning is always a very hot topic when it is about SQL Server. SQL Server Performance Tuning is a very challenging subject that requires expertise in Database Administration and Database Development. I always have enjoyed talking about SQL Server Performance tuning subject. However, in India, it’s actually the very first time someone is presenting on this interesting subject, so this time I had the biggest challenge to present this session. Frequently enough, we get these two kind of questions: How to turn off parallelism as it is reducing performance? How to turn on parallelism as I want more performance? The reality is that not everyone knows what exactly is needed by their system. In this session, I have attempted to answer this very question. I’ve decided to provide a balanced view but stay away from theory, which leads us to say “It depends”. The session will have a clear message about this towards its end. Deck Details Slides: 45+ Demos: 7+ Bonus Quiz: 5 Images: 10+ Session delivery time: 52 Mins + 8 Mins of Q & A I have presented this session a couple of times to my friends and so far have received good feedback. Oftentimes, when people hear that I am going to present 45 slides, they all say it is too much to cover. However, when I am done with the session the usual reaction is that I truly gave justice to those slides. Action Item Here are a few of the action items for all of those who are going to attend this session: If you want to attend the session, just come early. There’s a good chance that you may not get a seat because right before me, there is a session from SQL Guru Vinod Kumar. He performs a powerful delivery of million concepts in just a little time. Quiz. I will be asking few questions during the session as well as before the session starts. If you get the correct answer, I will give unique learning material for you. You may not want to miss this learning opportunity at any cosst. Session Details Title: Speed Up! – Parallel Processes and Unparalleled Performance (Add to Calendar) Abstract: “More CPU, More Performance” – A  very common understanding is that usage of multiple CPUs can improve the performance of the query. To get a maximum performance out of any query, one has to master various aspects of the parallel processes. In this deep-dive session, we will explore this complex subject with a very simple interactive demo. Attendees will walk away with proper understanding of CX_PACKET wait types, MAXDOP, parallelism threshold and various other concepts. Date and Time: March 23, 2012, 12:15 to 13:15 Location: Hotel Lalit Ashok - Kumara Krupa High Grounds, Bengaluru – 560001, Karnataka, India. Add to Calendar Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Interview Questions and Answers, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• Functional/nonfunctional requirements VS design ideas

  - by Nicholas Chow

  Problem domain Functional requirements defines what a system does. Non-Functional requirements defines quality attributes of what the system does as a whole.(performance, security, reliability, volume, useability, etc.) Constraints limits the design space, they restrict designers to certain types of solutions. Solution domain Design ideas , defines how the system does it. For example a stakeholder need might be we want to increase our sales, therefore we must improve the usability of our webshop so more customers will purchase, a requirement can be written for this. (problem domain) Design takes this further into the solution domain by saying "therefore we want to offer credit card payments in addition to the current prepayment option". My problem is that the transition phase from requirement to design seems really vague, therefore when writing requirements I am often confused whether or not I incorporated design ideas in my requirements, that would make my requirement wrong. Another problem is that I often write functional requirements as what a system does, and then I also specify in what timeframe it must be done. But is this correct? Is it then a still a functional requirement or a non functional one? Is it better to seperate it into two distinct requirements? Here are a few requirements I wrote: FR1 Registration of Organizer FR1 describes the registration of an Organizer on CrowdFundum FR1.1 The system shall display a registration form on the website. FR1.2 The system shall require a Name, Username, Document number passport/ID card, Address, Zip code, City, Email address, Telephone number, Bank account, Captcha code on the registration form when a user registers. FR1.4 The system shall display an error message containing: “Registration could not be completed” to the subscriber within 1 seconds after the system check of the registration form was unsuccessful. FR1.5 The system shall send a verification email containing a verification link to the subscriber within 30 seconds after the system check of the registration form was successful. FR1.6 The system shall add the newly registered Organizer to the user base within 5 seconds after the verification link was accessed. FR2 Organizer submits a Project FR2 describes the submission of a Project by an Organizer on CrowdFundum - FR2 The system shall display a submit Project form to the Organizer accounts on the website.< - FR2.3 The system shall check for completeness the Name of the Project, 1-3 Photo’s, Keywords of the Project, Punch line, Minimum and maximum amount of people, Funding threshold, One or more reward tiers, Schedule of when what will be organized, Budget plan, 300-800 Words of additional information about the Project, Contact details within 1 secondin after an Organizer submits the submit Project form. - FR2.8 The system shall add to the homepage in the new Projects category the Project link within 30 seconds after the system made a Project webpage - FR2.9 The system shall include in the Project link for the homepage : Name of the Project, 1 Photo, Punch line within 30 seconds after the system made a Project webpage. Questions: FR 1.1 : Have I incorporated a design idea here, would " the system shall have a registration form" be a better functional requirement? F1.2 ,2.3 : Is this not singular? Would the conditions be better written for each its own separate requirement FR 1.4: Is this a design idea? Is this a correct functional requirement or have I incorporated non functional(performance) in it? Would it be better if I written it like this: FR1 The system shall display an error message when check is unsuccessful. NFR: The system will respond to unsuccesful registration form checks within 1 seconds. Same question with FR 2.8 and 2.9. FR2.3: The system shall check for "completeness", is completeness here used ambigiously? Should I rephrase it? FR1.2: I added that the system shall require a "Captcha code" is this a functional requirement or does it belong to the "security aspect" of a non functional requirement. I am eagerly waiting for your response. Thanks!

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• To SYNC or not to SYNC – Part 4

  - by AshishRay

  This is Part 4 of a multi-part blog article where we are discussing various aspects of setting up Data Guard synchronous redo transport (SYNC). In Part 1 of this article, I debunked the myth that Data Guard SYNC is similar to a two-phase commit operation. In Part 2, I discussed the various ways that network latency may or may not impact a Data Guard SYNC configuration. In Part 3, I talked in details regarding why Data Guard SYNC is a good thing, and the distance implications you have to keep in mind. In this final article of the series, I will talk about how you can nicely complement Data Guard SYNC with the ability to failover in seconds. Wait - Did I Say “Seconds”? Did I just say that some customers do Data Guard failover in seconds? Yes, Virginia, there is a Santa Claus. Data Guard has an automatic failover capability, aptly called Fast-Start Failover. Initially available with Oracle Database 10g Release 2 for Data Guard SYNC transport mode (and enhanced in Oracle Database 11g to support Data Guard ASYNC transport mode), this capability, managed by Data Guard Broker, lets your Data Guard configuration automatically failover to a designated standby database. Yes, this means no human intervention is required to do the failover. This process is controlled by a low footprint Data Guard Broker client called Observer, which makes sure that the primary database and the designated standby database are behaving like good kids. If something bad were to happen to the primary database, the Observer, after a configurable threshold period, tells that standby, “Your time has come, you are the chosen one!” The standby dutifully follows the Observer directives by assuming the role of the new primary database. The DBA or the Sys Admin doesn’t need to be involved. And - in case you are following this discussion very closely, and are wondering … “Hmmm … what if the old primary is not really dead, but just network isolated from the Observer or the standby - won’t this lead to a split-brain situation?” The answer is No - It Doesn’t. With respect to why-it-doesn’t, I am sure there are some smart DBAs in the audience who can explain the technical reasons. Otherwise - that will be the material for a future blog post. So - this combination of SYNC and Fast-Start Failover is the nirvana of lights-out, integrated HA and DR, as practiced by some of our advanced customers. They have observed failover times (with no data loss) ranging from single-digit seconds to tens of seconds. With this, they support operations in industry verticals such as manufacturing, retail, telecom, Internet, etc. that have the most demanding availability requirements. One of our leading customers with massive cloud deployment initiatives tells us that they know about server failures only after Data Guard has automatically completed the failover process and the app is back up and running! Needless to mention, Data Guard Broker has the integration hooks for interfaces such as JDBC and OCI, or even for custom apps, to ensure the application gets automatically rerouted to the new primary database after the database level failover completes. Net Net? To sum up this multi-part blog article, Data Guard with SYNC redo transport mode, plus Fast-Start Failover, gives you the ideal triple-combo - that is, it gives you the assurance that for critical outages, you can failover your Oracle databases: very fast without human intervention, and without losing any data. In short, it takes the element of risk out of critical IT operations. It does require you to be more careful with your network and systems planning, but as far as HA is concerned, the benefits outweigh the investment costs. So, this is what we in the MAA Development Team believe in. What do you think? How has your deployment experience been? We look forward to hearing from you!

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• Stale statistics on a newly created temporary table in a stored procedure can lead to poor performance

  - by sqlworkshops

  When you create a temporary table you expect a new table with no past history (statistics based on past existence), this is not true if you have less than 6 updates to the temporary table. This might lead to poor performance of queries which are sensitive to the content of temporary tables.I was optimizing SQL Server Performance at one of my customers who provides search functionality on their website. They use stored procedure with temporary table for the search. The performance of the search depended on who searched what in the past, option (recompile) by itself had no effect. Sometimes a simple search led to timeout because of non-optimal plan usage due to this behavior. This is not a plan caching issue rather temporary table statistics caching issue, which was part of the temporary object caching feature that was introduced in SQL Server 2005 and is also present in SQL Server 2008 and SQL Server 2012. In this customer case we implemented a workaround to avoid this issue (see below for example for workarounds).When temporary tables are cached, the statistics are not newly created rather cached from the past and updated based on automatic update statistics threshold. Caching temporary tables/objects is good for performance, but caching stale statistics from the past is not optimal.We can work around this issue by disabling temporary table caching by explicitly executing a DDL statement on the temporary table. One possibility is to execute an alter table statement, but this can lead to duplicate constraint name error on concurrent stored procedure execution. The other way to work around this is to create an index.I think there might be many customers in such a situation without knowing that stale statistics are being cached along with temporary table leading to poor performance.Ideal solution is to have more aggressive statistics update when the temporary table has less number of rows when temporary table caching is used. I will open a connect item to report this issue.Meanwhile you can mitigate the issue by creating an index on the temporary table. You can monitor active temporary tables using Windows Server Performance Monitor counter: SQL Server: General Statistics->Active Temp Tables. The script to understand the issue and the workaround is listed below:set nocount onset statistics time offset statistics io offdrop table tab7gocreate table tab7 (c1 int primary key clustered, c2 int, c3 char(200))gocreate index test on tab7(c2, c1, c3)gobegin trandeclare @i intset @i = 1while @i <= 50000begininsert into tab7 values (@i, 1, ‘a’)set @i = @i + 1endcommit trangoinsert into tab7 values (50001, 1, ‘a’)gocheckpointgodrop proc test_slowgocreate proc test_slow @i intasbegindeclare @j intcreate table #temp1 (c1 int primary key)insert into #temp1 (c1) select @iselect @j = t7.c1 from tab7 t7 inner join #temp1 t on (t7.c2 = t.c1)endgodbcc dropcleanbuffersset statistics time onset statistics io ongo–high reads as expected for parameter ’1'exec test_slow 1godbcc dropcleanbuffersgo–high reads that are not expected for parameter ’2'exec test_slow 2godrop proc test_with_recompilegocreate proc test_with_recompile @i intasbegindeclare @j intcreate table #temp1 (c1 int primary key)insert into #temp1 (c1) select @iselect @j = t7.c1 from tab7 t7 inner join #temp1 t on (t7.c2 = t.c1)option (recompile)endgodbcc dropcleanbuffersset statistics time onset statistics io ongo–high reads as expected for parameter ’1'exec test_with_recompile 1godbcc dropcleanbuffersgo–high reads that are not expected for parameter ’2'–low reads on 3rd execution as expected for parameter ’2'exec test_with_recompile 2godrop proc test_with_alter_table_recompilegocreate proc test_with_alter_table_recompile @i intasbegindeclare @j intcreate table #temp1 (c1 int primary key)–to avoid caching of temporary tables one can create a constraint–but this might lead to duplicate constraint name error on concurrent usagealter table #temp1 add constraint test123 unique(c1)insert into #temp1 (c1) select @iselect @j = t7.c1 from tab7 t7 inner join #temp1 t on (t7.c2 = t.c1)option (recompile)endgodbcc dropcleanbuffersset statistics time onset statistics io ongo–high reads as expected for parameter ’1'exec test_with_alter_table_recompile 1godbcc dropcleanbuffersgo–low reads as expected for parameter ’2'exec test_with_alter_table_recompile 2godrop proc test_with_index_recompilegocreate proc test_with_index_recompile @i intasbegindeclare @j intcreate table #temp1 (c1 int primary key)–to avoid caching of temporary tables one can create an indexcreate index test on #temp1(c1)insert into #temp1 (c1) select @iselect @j = t7.c1 from tab7 t7 inner join #temp1 t on (t7.c2 = t.c1)option (recompile)endgoset statistics time onset statistics io ondbcc dropcleanbuffersgo–high reads as expected for parameter ’1'exec test_with_index_recompile 1godbcc dropcleanbuffersgo–low reads as expected for parameter ’2'exec test_with_index_recompile 2go

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• Upcoming Carbon Tax in South Africa

  - by Evelyn Neumayr

  By Elena Avesani, Principal Product Strategy Manager, Oracle In 2012, the South Africa National Treasury announced the plan to impose a carbon tax to cut carbon emissions that are blamed for climate change. South Africa is ranked among the top 20 countries measured by absolute carbon dioxide emissions, with emissions per capita in the region of 10 metric tons per annum and over 90% of South Africa's energy produced by burning fossil fuels. The top 40 largest companies in the country are responsible for 207 million tons of carbon dioxide, directly emitting 20 percent of South Africa’s carbon output. The legislation, originally scheduled to be implemented from January 2015 to 31 December 2019, is now delayed to January 2016. It will levy a carbon tax of R120 (US$11) per ton of CO2, rising then by 10 percent a year until 2020, while all sectors bar electricity will be able to claim additional relief of at least 10 percent. The South African treasury proposed a 60 percent tax-free threshold on emissions for all sectors, including electricity, petroleum, iron, steel and aluminum. Oracle Environmental Accounting and Reporting (EA&R) supports these needs and guarantees consistency across organizations in how data is collected, retained, controlled, consolidated and used in calculating and reporting emissions inventory. EA&R also enables companies to develop an enterprise-wide data view that includes all 5 of the key sustainability categories: carbon emissions, energy, water, materials and waste. Thanks to its native integration with Oracle E-Business Suite and JD Edwards EnterpriseOne ERP Financials and Inventory Systems and the capability of capturing environmental data across business silos, Oracle Environmental Accounting and Reporting is uniquely positioned to support a strategic approach to carbon management that drives business value. Sources: Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} African Utility Week BDlive Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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• Rotating WebLogic Server logs to avoid large files using WLST.

  - by adejuanc

  By default, when WebLogic Server instances are started in development mode, the server automatically renames (rotates) its local server log file as SERVER_NAME.log.n.  For the remainder of the server session, log messages accumulate in SERVER_NAME.log until the file grows to a size of 500 kilobytes.Each time the server log file reaches this size, the server renames the log file and creates a new SERVER_NAME.log to store new messages. By default, the rotated log files are numbered in order of creation filenamennnnn, where filename is the name configured for the log file. You can configure a server instance to include a time and date stamp in the file name of rotated log files; for example, server-name-%yyyy%-%mm%-%dd%-%hh%-%mm%.log.By default, when server instances are started in production mode, the server rotates its server log file whenever the file grows to 5000 kilobytes in size. It does not rotate the local server log file when the server is started. For more information about changing the mode in which a server starts, see Change to production mode in the Administration Console Online Help.You can change these default settings for log file rotation. For example, you can change the file size at which the server rotates the log file or you can configure a server to rotate log files based on a time interval. You can also specify the maximum number of rotated files that can accumulate. After the number of log files reaches this number, subsequent file rotations delete the oldest log file and create a new log file with the latest suffix.  Note: WebLogic Server sets a threshold size limit of 500 MB before it forces a hard rotation to prevent excessive log file growth. To Rotate via WLST : #invoke WLSTC:\>java weblogic.WLST#connect WLST to an Administration Serverawls:/offline> connect('username','password')#navigate to the ServerRuntime MBean hierarchywls:/mydomain/serverConfig> serverRuntime()wls:/mydomain/serverRuntime>ls()#navigate to the server LogRuntimeMBeanwls:/mydomain/serverRuntime> cd('LogRuntime/myserver')wls:/mydomain/serverRuntime/LogRuntime/myserver> ls()-r-- Name myserver-r-- Type LogRuntime-r-x forceLogRotation java.lang.Void :#force the immediate rotation of the server log filewls:/mydomain/serverRuntime/LogRuntime/myserver> cmo.forceLogRotation()wls:/mydomain/serverRuntime/LogRuntime/myserver> The server immediately rotates the file and prints the following message: <Mar 2, 2012 3:23:01 PM EST> <Info> <Log Management> <BEA-170017> <The log file C:\diablodomain\servers\myserver\logs\myserver.log will be rotated. Reopen the log file if tailing has stopped. This can happen on some platforms like Windows.><Mar 2, 2012 3:23:01 PM EST> <Info> <Log Management> <BEA-170018> <The log file has been rotated to C:\diablodomain\servers\myserver\logs\myserver.log00001. Log messages will continue to be logged in C:\diablodomain\servers\myserver\logs\myserver.log.> To specify the Location of the archived Log Files The following command specifies the directory location for the archived log files using the -Dweblogic.log.LogFileRotationDir Java startup option: java -Dweblogic.log.LogFileRotationDir=c:\foo-Dweblogic.management.username=installadministrator-Dweblogic.management.password=installadministrator weblogic.Server For more information read the following documentation ; Using the WebLogic Scripting Tool http://download.oracle.com/docs/cd/E13222_01/wls/docs103/config_scripting/using_WLST.html Configuring WebLogic Logging Services http://download.oracle.com/docs/cd/E12840_01/wls/docs103/logging/config_logs.html

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