multiple schema - Page 340

Oracle Shcema Name

- by Keith

How can I include the schema into my connection string inside my web.config.

how rspec creates database between specs

This is a bit of a naive / simple question. I'm having a hard time finding this info online. Basically, does rspec run rake db:test:prepare between every rspec group? Or is it between every example or model? Or does the schema get loaded once and then truncated between each. I need to add a rake task directly after this call to create a view since they are not supported in schema.rb. Either a link or explanation would be greatly appreciated so that I know where to insert my rake task to create a view. Or whether there is a callback like rake db:test:after_prepare thx

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Validation against 10K XSD - performance problem

- by stck777

I have an XSD scheme which has 10K lines. It takes 5 seconds to validate my XML with 500 lines. I get dynamically XML via POST from external server, on every click of the user on my homepage. The validation takes 5+ seconds, which is very much for every click of the user. PHP Example: $doc = new DOMDocument(); $doc->load('file.xml'); //100 to 500 lines $doc->schemaValidate('schema.xsd'); //schema.xsd 10 000 lines Do you have any idea how I can validate the XML against the XSD faster?

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Mongoose Not Creating Indexes

- by wintzer

I have been trying all afternoon to get my node.js application to create MongoDB indexes properly. I am using the Mongoose ODM and in my schema definition below I have the username field set to a unique index. The collection and document all get created properly, it's just the indexes that aren't working. All the documentation says that the ensureIndex command should be run at startup to create any indexes, but none are being made. I'm using MongoLab for hosting if that matters. I have also repeatedly dropped the collection. Please tell me what I'm doing wrong. var schemaUser = new mongoose.Schema({ username: {type: String, index: { unique: true }, required: true}, hash: String, created: {type: Date, default: Date.now} }, { collection:'Users' }); var User = mongoose.model('Users', schemaUser); var newUser = new Users({username:'wintzer'}) newUser.save(function(err) { if (err) console.log(err); });

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Lithium: Run filter after find() to format output

- by Housni

I wanted to specify the output of a field from within my model so I added a date key to my $_schema: models/Tags.php <?php protected $_schema = array( 'id' => array('type' => 'integer', 'key' => 'primary'), 'title' => array('type' => 'string'), 'created' => array('type' => 'integer', 'date' => 'F jS, Y - g:i a'), 'modified' => array('type' => 'integer') ); ?> I store my time as an unsigned integer in the db (output of time()). I want my base model to format any field that has the date key for output. I thought the best place to do that would be right after a find: extensions/data/Model.php <?php static::applyFilter('find', function($self, $params, $chain) { $schema = $self::schema(); $entity = $chain->next($self, $params, $chain); foreach ($schema as $field => $options) { if (array_key_exists('date', $options)) { //format as a date $params['data'][$field] = $entity->formatDate($field, $options['date']); } } return $entity; }); public function formatdate($entity, $field, $format, $timezone = 'Asia/Colombo') { $dt = new \DateTime(); $tz = new \DateTimeZone($timezone); $dt->setTimestamp($entity->$field); $dt->setTimezone($tz); return $dt->format($format); } ?> This doesn't seem to be working. When I execute a find all, this filter seems to get hit twice. The first time, $entity contains a count() of the results and only on the second hit does it contain the Records object. What am I doing wrong? How do I alter this so that simply doing <?= $tag->created; ?> in my view will format the date the way I want? This, essentially, needs to be an 'after filter', of sorts. EDIT If I can find a way to access the current model entity object (not the full namespaced path, $self contains that), I can probably solve my problem.

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Dynamically set the option values

- by user281180

I have 2 different lists: EmployeeNames and Names I read the values in Names and that of EmployeeNames. If EmployeeNames exists in Names, I must not add that value to "ToSelectBox" but to "FromSelectBox". If EmployeeNames doesn`t exist in Names, I must add that value to "ToSelectBox" but not to "FromSelectBox". How can I do that dynamically? I have 2 option values as follows: <select id="fromSelectBox" multiple="multiple" > <% foreach (var item in Model.EmployeeNames) { %> <option value="<%=Html.Encode(Item.Text)%>"><%=Html.Encode(item.Text)%></option> <%} %> </select> select id="ToSelectBox" multiple="multiple" > <% foreach (var item in Model.Names) { %> <option value="<%=Html.Encode(Item.Text)%>"><%=Html.Encode(item.Text)%></option> <%} %> </select>

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What's the best way to store custom objects in relational database?

- by user342610

I have my objects with their properties. Objects could change their structure: properties may be added/removed/changed. Objects could be absolutely dropped. So object's metadata (description, classes, call them like you want :) )could be changed. The database should store objects schemas and instances of these objects. What's the best way to organise a relational database structure to store data mentioned above? Currently I see only two ways: 1) Store objects schemas in a few tables: schema general data,schema properties, possible properties types. Store instances in their tables: instance general data, a few tables - per each type from possible properties types table to store instance properties data. And so on. 2) store objects schemas like in p1 but store instances like XML files in one table: one table for general instance info and one table with instance XML. please, don't ask why/for what I need this. Just need to store custom objects and DB should work fast :)

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How (and if) to write a single-consumer queue using the task parallel library?

- by Eric

I've heard a bunch of podcasts recently about the TPL in .NET 4.0. Most of them describe background activities like downloading images or doing a computation, using tasks so that the work doesn't interfere with a GUI thread. Most of the code I work on has more of a multiple-producer / single-consumer flavor, where work items from multiple sources must be queued and then processed in order. One example would be logging, where log lines from multiple threads are sequentialized into a single queue for eventual writing to a file or database. All the records from any single source must remain in order, and records from the same moment in time should be "close" to each other in the eventual output. So multiple threads or tasks or whatever are all invoking a queuer: lock( _queue ) // or use a lock-free queue! { _queue.enqueue( some_work ); _queueSemaphore.Release(); } And a dedicated worker thread processes the queue: while( _queueSemaphore.WaitOne() ) { lock( _queue ) { some_work = _queue.dequeue(); } deal_with( some_work ); } It's always seemed reasonable to dedicate a worker thread for the consumer side of these tasks. Should I write future programs using some construct from the TPL instead? Which one? Why?

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XSLT ... I can'f find a (working) find minimum value in XML and set variable

- by Bob

I've search for hours and not found an example that allows for the very first position to be the lowest. I'm getting 'False' instead of the value returned .... EDIT: Oddly enough if I run a 2nd instance as MAX_Landed with ascending it returns a value just fine. If I switch the order in the XSLT the first instance will return 'False' and the 2nd will work. Hope I'm making sense ..... Example XML which I can't get formatted to show correctly and in a hurry so you get the gist I hope: <?xml version="1.0"?> <GetLowestOfferListingsForASINResponse xmlns="http://mws.amazonservices.com/schema/Products/2011-10-01"> <GetLowestOfferListingsForASINResult ASIN="0470067802" status="Success"> <AllOfferListingsConsidered>false</AllOfferListingsConsidered> <Product xmlns="http://mws.amazonservices.com/schema/Products/2011-10-01" xmlns:ns2="http://mws.amazonservices.com/schema/Products/2011-10-01/default.xsd"> <LowestOfferListings> <LowestOfferListing> <Qualifiers> <ItemCondition>Used</ItemCondition> <ItemSubcondition>Good</ItemSubcondition> </Qualifiers> <Price> <LandedPrice> <Amount>15.71</Amount> </LandedPrice> </Price> </LowestOfferListing> <LowestOfferListing> <Qualifiers> <ItemCondition>Used</ItemCondition> <ItemSubcondition>Good</ItemSubcondition> </Qualifiers> <Price> <LandedPrice> <Amount>16.71</Amount> </LandedPrice> </Price> </LowestOfferListing> <LowestOfferListing> <Qualifiers> <ItemCondition>Used</ItemCondition> <ItemSubcondition>Good</ItemSubcondition> </Qualifiers> <Price> <LandedPrice> <Amount>18.71</Amount> </LandedPrice> </Price> </LowestOfferListing> </LowestOfferListings> </Product> </GetLowestOfferListingsForASINResult> </GetLowestOfferListingsForASINResponse> Example XSLT : <?xml version="1.0" encoding="utf-8"?> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0" xmlns:amz="http://mws.amazonservices.com/schema/Products/2011-10-01" exclude-result-prefixes="amz"> <xsl:output method="xml" version="1.0" encoding="utf-8" indent="yes"/> <xsl:template match="/"> <xsl:variable name="MIN_Landed"> <xsl:for-each select="//Amount"> <xsl:sort data-type="number" order="ascending"/> <xsl:if test="position()=1"><xsl:value-of select="."/></xsl:if> </xsl:for-each> </xsl:variable> <FMPXMLRESULT xmlns="http://www.filemaker.com/fmpxmlresult"> <ERRORCODE>0</ERRORCODE> <PRODUCT BUILD="" NAME="" VERSION=""/> <DATABASE DATEFORMAT="M/d/yyyy" LAYOUT="" NAME="" RECORDS="1" TIMEFORMAT="h:mm:ss a"/> <METADATA> <FIELD EMPTYOK="YES" MAXREPEAT="1" NAME="DATA" TYPE="TEXT"/> <FIELD EMPTYOK="YES" MAXREPEAT="1" NAME="Min_Landed" TYPE="TEXT"/> </METADATA> <RESULTSET> <xsl:attribute name="FOUND">1</xsl:attribute> <xsl:for-each select="amz:GetLowestOfferListingsForASINResponse/amz:GetLowestOfferListingsForASINResult/amz:Product/amz:LowestOfferListings/amz:LowestOfferListing"> <ROW> <xsl:attribute name="MODID">0</xsl:attribute> <xsl:attribute name="RECORDID">1</xsl:attribute> <COL> <DATA> <xsl:value-of select="amz:Qualifiers/amz:ItemCondition"/> </DATA> </COL> <COL> <DATA> <xsl:value-of select="$MIN_Landed"/> </DATA> </COL> </ROW> </xsl:for-each> </RESULTSET> </FMPXMLRESULT> </xsl:template> </xsl:stylesheet> HELP PLEASE! I really didn't want to post so much Amazon code but here it is stripped down to a bare bones response

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simple GET validation

- by Andrew

I have GET[] input and would like to carry out their validation. The input data is always a number by. Schema. I want to make sure that the pass number and the appropriate amount - not to throw the sql query. at this moment I am using the procedures $cc = $_GET['cc']; if ($cc=='') $cc='9012';$find=array("..", "/", "\\"); $replace=array("", "", ""); $cc=str_replace($find, $replace, $cc); $eic = $_GET['eic']; .... ect. // where f.ex. 9012 is an real existing data (in dbase) to generate sucure sql question GET[] variable data schema $_GET[$cc] - always 4 digits $_GET[$eic] - always 4 digits $_GET[$iy] - always 4 digits $_GET[$ir] - always 1 digit Can you show me a better way to secure my GET?

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Core Data to-many relationship in code

- by Jan Bezemer

I have three entities: Session, User and Test. A session has 0-many users and a user can perform 0-6 tests. (I say 0 but in the real application always at least 1 is required, at least 1 user for a session and at least 1 test for a user. But I say 0 to express an empty start.) All entities have their own specific data attributes too. A user has a name, A session has a name, a test has six values to be filled in by the user, and so on. But my issue is with the relationships. How do I set multiple users and have them added to one session (same goes for multiple tests for one user). How do I show the content in a right way? How do I show a session that has multiple users and these users having completed multiple tests? Here's my code so far with regard to issue 1: Session *session = [NSEntityDescription insertNewObjectForEntityForName:@"Session" inManagedObjectContext:context]; session.name = @"Session 1"; User *users = [NSEntityDescription insertNewObjectForEntityForName:@"User" inManagedObjectContext:context]; users.age = [NSNumber numberWithInt:28]; users.session = session; //sessie.users = users; [sessie addUserObject:users]; With regard to issue 2: I can log the session, but I can't get the user(s) logged from a session. NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"Session" inManagedObjectContext:context]; [fetchRequest setEntity:entity]; NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error]; for (Session *info in fetchedObjects) { NSLog(@"Name: %@", info.name); NSLog(@"Having problems with this: %@",info.user); //User *details = info.user; //NSLog(@"User: %@", details.age); }

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.NET project: unified wrapper for object databases.

- by Steve

I am considering doing a project which would provide unified API and tools (import/export, etc.) for object databases (e.g. Caché, Objectivity) for .NET. It would provide: schema generation from CLR classes, generation of C# classes from given OODBMs schema, API for deleting, creating and updating objects, Linq provider, API for calling object's methods on DB server, some of OODBMs provide some kind of SQL support, so API for this, providers for Caché and Objectivity in first phase. Does any project which implements any of above exist? Can this be achieved with NHibernate dialects? or are OODBMs so different than RDBMs that it worth doing separate framework for them?

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Membership provider to use or not to use?????

- by Shekhar_Pro

Hi every one , Wish u all a Happy New Year. I am developing a website that uses facebook. Now for managing user i thought Using membrship provider. and choose'd to develop a Custom membership provider. Now my problem is that My data base schema dosn't match the Standred membership schema and the functions provided to Override take different argument than i expect. Like membership uses username as a username to log in. But i haev to use User email ID as the user name, also its searching functions is based on using Username as way to serach but i want it to search by UserID. Same Goes for User insertion, deletion, Updation.. please help me .... Edit Its just an idea, Would it be feasible to forcefully pass my values in the arguments and then handle them in my code.

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Copying just the data from one Database to another

- by monksy

I'm not sure if this is the site for this question or not [if so put in the comment or vote to move it] How can I copy only the data from one database to another within the same server on SQL Server 2005? The two databases have the same schema but not the same data. I'm trying to get the data from one database to another. I am not able to restore from a snapshot [that screws over the security settings on the database]. I'm not able to use the import data wizard, because that is trying to copy over schema data as well.

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Launching a WPF Window in a Separate Thread, Part 1

- by Reed

Typically, I strongly recommend keeping the user interface within an application’s main thread, and using multiple threads to move the actual “work” into background threads. However, there are rare times when creating a separate, dedicated thread for a Window can be beneficial. This is even acknowledged in the MSDN samples, such as the Multiple Windows, Multiple Threads sample. However, doing this correctly is difficult. Even the referenced MSDN sample has major flaws, and will fail horribly in certain scenarios. To ease this, I wrote a small class that alleviates some of the difficulties involved. The MSDN Multiple Windows, Multiple Threads Sample shows how to launch a new thread with a WPF Window, and will work in most cases. The sample code (commented and slightly modified) works out to the following: // Create a thread Thread newWindowThread = new Thread(new ThreadStart( () => { // Create and show the Window Window1 tempWindow = new Window1(); tempWindow.Show(); // Start the Dispatcher Processing System.Windows.Threading.Dispatcher.Run(); })); // Set the apartment state newWindowThread.SetApartmentState(ApartmentState.STA); // Make the thread a background thread newWindowThread.IsBackground = true; // Start the thread newWindowThread.Start(); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This sample creates a thread, marks it as single threaded apartment state, and starts the Dispatcher on that thread. That is the minimum requirements to get a Window displaying and handling messages correctly, but, unfortunately, has some serious flaws. The first issue – the created thread will run continuously until the application shuts down, given the code in the sample. The problem is that the ThreadStart delegate used ends with running the Dispatcher. However, nothing ever stops the Dispatcher processing. The thread was created as a Background thread, which prevents it from keeping the application alive, but the Dispatcher will continue to pump dispatcher frames until the application shuts down. In order to fix this, we need to call Dispatcher.InvokeShutdown after the Window is closed. This would require modifying the above sample to subscribe to the Window’s Closed event, and, at that point, shutdown the Dispatcher: // Create a thread Thread newWindowThread = new Thread(new ThreadStart( () => { Window1 tempWindow = new Window1(); // When the window closes, shut down the dispatcher tempWindow.Closed += (s,e) => Dispatcher.CurrentDispatcher.BeginInvokeShutdown(DispatcherPriority.Background); tempWindow.Show(); // Start the Dispatcher Processing System.Windows.Threading.Dispatcher.Run(); })); // Setup and start thread as before This eliminates the first issue. Now, when the Window is closed, the new thread’s Dispatcher will shut itself down, which in turn will cause the thread to complete. The above code will work correctly for most situations. However, there is still a potential problem which could arise depending on the content of the Window1 class. This is particularly nasty, as the code could easily work for most windows, but fail on others. The problem is, at the point where the Window is constructed, there is no active SynchronizationContext. This is unlikely to be a problem in most cases, but is an absolute requirement if there is code within the constructor of Window1 which relies on a context being in place. While this sounds like an edge case, it’s fairly common. For example, if a BackgroundWorker is started within the constructor, or a TaskScheduler is built using TaskScheduler.FromCurrentSynchronizationContext() with the expectation of synchronizing work to the UI thread, an exception will be raised at some point. Both of these classes rely on the existence of a proper context being installed to SynchronizationContext.Current, which happens automatically, but not until Dispatcher.Run is called. In the above case, SynchronizationContext.Current will return null during the Window’s construction, which can cause exceptions to occur or unexpected behavior. Luckily, this is fairly easy to correct. We need to do three things, in order, prior to creating our Window: Create and initialize the Dispatcher for the new thread manually Create a synchronization context for the thread which uses the Dispatcher Install the synchronization context Creating the Dispatcher is quite simple – The Dispatcher.CurrentDispatcher property gets the current thread’s Dispatcher and “creates a new Dispatcher if one is not already associated with the thread.” Once we have the correct Dispatcher, we can create a SynchronizationContext which uses the dispatcher by creating a DispatcherSynchronizationContext. Finally, this synchronization context can be installed as the current thread’s context via SynchronizationContext.SetSynchronizationContext. These three steps can easily be added to the above via a single line of code: // Create a thread Thread newWindowThread = new Thread(new ThreadStart( () => { // Create our context, and install it: SynchronizationContext.SetSynchronizationContext( new DispatcherSynchronizationContext( Dispatcher.CurrentDispatcher)); Window1 tempWindow = new Window1(); // When the window closes, shut down the dispatcher tempWindow.Closed += (s,e) => Dispatcher.CurrentDispatcher.BeginInvokeShutdown(DispatcherPriority.Background); tempWindow.Show(); // Start the Dispatcher Processing System.Windows.Threading.Dispatcher.Run(); })); // Setup and start thread as before This now forces the synchronization context to be in place before the Window is created and correctly shuts down the Dispatcher when the window closes. However, there are quite a few steps. In my next post, I’ll show how to make this operation more reusable by creating a class with a far simpler API…

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Combination of Operating Mode and Commit Strategy

- by Kevin Yang

If you want to populate a source into multiple targets, you may also want to ensure that every row from the source affects all targets uniformly (or separately). Let’s consider the Example Mapping below. If a row from SOURCE causes different changes in multiple targets (TARGET_1, TARGET_2 and TARGET_3), for example, it can be successfully inserted into TARGET_1 and TARGET_3, but failed to be inserted into TARGET_2, and the current Mapping Property TLO (target load order) is “TARGET_1 -> TARGET_2 -> TARGET_3”. What should Oracle Warehouse Builder do, in order to commit the appropriate data to all affected targets at the same time? If it doesn’t behave as you intended, the data could become inaccurate and possibly unusable. Example Mapping In OWB, we can use Mapping Configuration Commit Strategies and Operating Modes together to achieve this kind of requirements. Below we will explore the combination of these two features and how they affect the results in the target tables Before going to the example, let’s review some of the terms we will be using (Details can be found in white paper Oracle® Warehouse Builder Data Modeling, ETL, and Data Quality Guide11g Release 2): Operating Modes: Set-Based Mode: Warehouse Builder generates a single SQL statement that processes all data and performs all operations. Row-Based Mode: Warehouse Builder generates statements that process data row by row. The select statement is in a SQL cursor. All subsequent statements are PL/SQL. Row-Based (Target Only) Mode: Warehouse Builder generates a cursor select statement and attempts to include as many operations as possible in the cursor. For each target, Warehouse Builder inserts each row into the target separately. Commit Strategies: Automatic: Warehouse Builder loads and then automatically commits data based on the mapping design. If the mapping has multiple targets, Warehouse Builder commits and rolls back each target separately and independently of other targets. Use the automatic commit when the consequences of multiple targets being loaded unequally are not great or are irrelevant. Automatic correlated: It is a specialized type of automatic commit that applies to PL/SQL mappings with multiple targets only. Warehouse Builder considers all targets collectively and commits or rolls back data uniformly across all targets. Use the correlated commit when it is important to ensure that every row in the source affects all affected targets uniformly. Manual: select manual commit control for PL/SQL mappings when you want to interject complex business logic, perform validations, or run other mappings before committing data. Combination of the commit strategy and operating mode To understand the effects of each combination of operating mode and commit strategy, I’ll illustrate using the following example Mapping. Firstly we insert 100 rows into the SOURCE table and make sure that the 99th row and 100th row have the same ID value. And then we create a unique key constraint on ID column for TARGET_2 table. So while running the example mapping, OWB tries to load all 100 rows to each of the targets. But the mapping should fail to load the 100th row to TARGET_2, because it will violate the unique key constraint of table TARGET_2. With different combinations of Commit Strategy and Operating Mode, here are the results ¦ Set-based/ Correlated Commit: Configuration of Example mapping: Result: What’s happening: A single error anywhere in the mapping triggers the rollback of all data. OWB encounters the error inserting into Target_2, it reports an error for the table and does not load the row. OWB rolls back all the rows inserted into Target_1 and does not attempt to load rows to Target_3. No rows are added to any of the target tables. ¦ Row-based/ Correlated Commit: Configuration of Example mapping: Result: What’s happening: OWB evaluates each row separately and loads it to all three targets. Loading continues in this way until OWB encounters an error loading row 100th to Target_2. OWB reports the error and does not load the row. It rolls back the row 100th previously inserted into Target_1 and does not attempt to load row 100 to Target_3. Then, if there are remaining rows, OWB will continue loading them, resuming with loading rows to Target_1. The mapping completes with 99 rows inserted into each target. ¦ Set-based/ Automatic Commit: Configuration of Example mapping: Result: What’s happening: When OWB encounters the error inserting into Target_2, it does not load any rows and reports an error for the table. It does, however, continue to insert rows into Target_3 and does not roll back the rows previously inserted into Target_1. The mapping completes with one error message for Target_2, no rows inserted into Target_2, and 100 rows inserted into Target_1 and Target_3 separately. ¦ Row-based/Automatic Commit: Configuration of Example mapping: Result: What’s happening: OWB evaluates each row separately for loading into the targets. Loading continues in this way until OWB encounters an error loading row 100 to Target_2 and reports the error. OWB does not roll back row 100th from Target_1, does insert it into Target_3. If there are remaining rows, it will continue to load them. The mapping completes with 99 rows inserted into Target_2 and 100 rows inserted into each of the other targets. Note: Automatic Correlated commit is not applicable for row-based (target only). If you design a mapping with the row-based (target only) and correlated commit combination, OWB runs the mapping but does not perform the correlated commit. In set-based mode, correlated commit may impact the size of your rollback segments. Space for rollback segments may be a concern when you merge data (insert/update or update/insert). Correlated commit operates transparently with PL/SQL bulk processing code. The correlated commit strategy is not available for mappings run in any mode that are configured for Partition Exchange Loading or that include a Queue, Match Merge, or Table Function operator. If you want to practice in your own environment, you can follow the steps: 1. Import the MDL file: commit_operating_mode.mdl 2. Fix the location for oracle module ORCL and deploy all tables under it. 3. Insert sample records into SOURCE table, using below plsql code: begin for i in 1..99 loop insert into source values(i, 'col_'||i); end loop; insert into source values(99, 'col_99'); end; 4. Configure MAPPING_1 to any combinations of operating mode and commit strategy you want to test. And make sure feature TLO of mapping is open. 5. Deploy Mapping “MAPPING_1”. 6. Run the mapping and check the result.

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SQL SERVER – Weekly Series – Memory Lane – #048

- by Pinal Dave

Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Order of Result Set of SELECT Statement on Clustered Indexed Table When ORDER BY is Not Used Above theory is true in most of the cases. However SQL Server does not use that logic when returning the resultset. SQL Server always returns the resultset which it can return fastest.In most of the cases the resultset which can be returned fastest is the resultset which is returned using clustered index. Effect of TRANSACTION on Local Variable – After ROLLBACK and After COMMIT One of the Jr. Developer asked me this question (What will be the Effect of TRANSACTION on Local Variable – After ROLLBACK and After COMMIT?) while I was rushing to an important meeting. I was getting late so I asked him to talk with his Application Tech Lead. When I came back from meeting both of them were looking for me. They said they are confused. I quickly wrote down following example for them. 2008 SQL SERVER – Guidelines and Coding Standards Complete List Download Coding standards and guidelines are very important for any developer on the path of a successful career. A coding standard is a set of guidelines, rules and regulations on how to write code. Coding standards should be flexible enough or should take care of the situation where they should not prevent best practices for coding. They are basically the guidelines that one should follow for better understanding. Download Guidelines and Coding Standards complete List Download Get Answer in Float When Dividing of Two Integer Many times we have requirements of some calculations amongst different fields in Tables. One of the software developers here was trying to calculate some fields having integer values and divide it which gave incorrect results in integer where accurate results including decimals was expected. Puzzle – Computed Columns Datatype Explanation SQL Server automatically does a cast to the data type having the highest precedence. So the result of INT and INT will be INT, but INT and FLOAT will be FLOAT because FLOAT has a higher precedence. If you want a different data type, you need to do an EXPLICIT cast. Renaming SP is Not Good Idea – Renaming Stored Procedure Does Not Update sys.procedures I have written many articles about renaming a tables, columns and procedures SQL SERVER – How to Rename a Column Name or Table Name, here I found something interesting about renaming the stored procedures and felt like sharing it with you all. The interesting fact is that when we rename a stored procedure using SP_Rename command, the Stored Procedure is successfully renamed. But when we try to test the procedure using sp_helptext, the procedure will be having the old name instead of new names. 2009 Insert Values of Stored Procedure in Table – Use Table Valued Function It is clear from the result set that , where I have converted stored procedure logic into the table valued function, is much better in terms of logic as it saves a large number of operations. However, this option should be used carefully. The performance of the stored procedure is “usually” better than that of functions. Interesting Observation – Index on Index View Used in Similar Query Recently, I was working on an optimization project for one of the largest organizations. While working on one of the queries, we came across a very interesting observation. We found that there was a query on the base table and when the query was run, it used the index, which did not exist in the base table. On careful examination, we found that the query was using the index that was on another view. This was very interesting as I have personally never experienced a scenario like this. In simple words, “Query on the base table can use the index created on the indexed view of the same base table.” Interesting Observation – Execution Plan and Results of Aggregate Concatenation Queries Working with SQL Server has never seemed to be monotonous – no matter how long one has worked with it. Quite often, I come across some excellent comments that I feel like acknowledging them as blog posts. Recently, I wrote an article on SQL SERVER – Execution Plan and Results of Aggregate Concatenation Queries Depend Upon Expression Location, which is well received in the community. 2010 I encourage all of you to go through complete series and write your own on the subject. If you write an article and send it to me, I will publish it on this blog with due credit to you. If you write on your own blog, I will update this blog post pointing to your blog post. SQL SERVER – ORDER BY Does Not Work – Limitation of the View 1 SQL SERVER – Adding Column is Expensive by Joining Table Outside View – Limitation of the View 2 SQL SERVER – Index Created on View not Used Often – Limitation of the View 3 SQL SERVER – SELECT * and Adding Column Issue in View – Limitation of the View 4 SQL SERVER – COUNT(*) Not Allowed but COUNT_BIG(*) Allowed – Limitation of the View 5 SQL SERVER – UNION Not Allowed but OR Allowed in Index View – Limitation of the View 6 SQL SERVER – Cross Database Queries Not Allowed in Indexed View – Limitation of the View 7 SQL SERVER – Outer Join Not Allowed in Indexed Views – Limitation of the View 8 SQL SERVER – SELF JOIN Not Allowed in Indexed View – Limitation of the View 9 SQL SERVER – Keywords View Definition Must Not Contain for Indexed View – Limitation of the View 10 SQL SERVER – View Over the View Not Possible with Index View – Limitations of the View 11 2011 Startup Parameters Easy to Configure If you are a regular reader of this blog, you must be aware that I have written about SQL Server Denali recently. Here is the quickest way to reach into the screen where we can change the startup parameters. Go to SQL Server Configuration Manager >> SQL Server Services >> Right Click on the Server >> Properties >> Startup Parameters 2012 Validating Unique Columnname Across Whole Database I sometimes come across very strange requirements and often I do not receive a proper explanation of the same. Here is the one of those examples. For example “Our business requirement is when we add new column we want it unique across current database.” Read the solution to this strange request in this blog post. Excel Losing Decimal Values When Value Pasted from SSMS ResultSet It is very common when users are coping the resultset to Excel, the floating point or decimals are missed. The solution is very much simple and it requires a small adjustment in the Excel. By default Excel is very smart and when it detects the value which is getting pasted is numeric it changes the column format to accommodate that. Basic Calculation and PEMDAS Order of Operation Read this interesting blog post for fantastic conversation about the subject. Copy Column Headers from Resultset – SQL in Sixty Seconds #027 – Video http://www.youtube.com/watch?v=x_-3tLqTRv0 Delete From Multiple Table – Update Multiple Table in Single Statement There are two questions which I get every single day multiple times. In my gmail, I have created standard canned reply for them. Let us see the questions here. I want to delete from multiple table in a single statement how will I do it? I want to update multiple table in a single statement how will I do it? Read the answer in the blog post. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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SQL SERVER – Weekly Series – Memory Lane – #032

- by Pinal Dave

Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Complete Series of Database Coding Standards and Guidelines SQL SERVER Database Coding Standards and Guidelines – Introduction SQL SERVER – Database Coding Standards and Guidelines – Part 1 SQL SERVER – Database Coding Standards and Guidelines – Part 2 SQL SERVER Database Coding Standards and Guidelines Complete List Download Explanation and Example – SELF JOIN When all of the data you require is contained within a single table, but data needed to extract is related to each other in the table itself. Examples of this type of data relate to Employee information, where the table may have both an Employee’s ID number for each record and also a field that displays the ID number of an Employee’s supervisor or manager. To retrieve the data tables are required to relate/join to itself. Insert Multiple Records Using One Insert Statement – Use of UNION ALL This is very interesting question I have received from new developer. How can I insert multiple values in table using only one insert? Now this is interesting question. When there are multiple records are to be inserted in the table following is the common way using T-SQL. Function to Display Current Week Date and Day – Weekly Calendar Straight blog post with script to find current week date and day based on the parameters passed in the function. 2008 In my beginning years, I have almost same confusion as many of the developer had in their earlier years. Here are two of the interesting question which I have attempted to answer in my early year. Even if you are experienced developer may be you will still like to read following two questions: Order Of Column In Index Order of Conditions in WHERE Clauses Example of DISTINCT in Aggregate Functions Have you ever used DISTINCT with the Aggregation Function? Here is a simple example about how users can do it. Create a Comma Delimited List Using SELECT Clause From Table Column Straight to script example where I explained how to do something easy and quickly. Compound Assignment Operators SQL SERVER 2008 has introduced new concept of Compound Assignment Operators. Compound Assignment Operators are available in many other programming languages for quite some time. Compound Assignment Operators is operator where variables are operated upon and assigned on the same line. PIVOT and UNPIVOT Table Examples Here is a very interesting question – the answer to the question can be YES or NO both. “If we PIVOT any table and UNPIVOT that table do we get our original table?” Read the blog post to get the explanation of the question above. 2009 What is Interim Table – Simple Definition of Interim Table The interim table is a table that is generated by joining two tables and not the final result table. In other words, when two tables are joined they create an interim table as resultset but the resultset is not final yet. It may be possible that more tables are about to join on the interim table, and more operations are still to be applied on that table (e.g. Order By, Having etc). Besides, it may be possible that there is no interim table; sometimes final table is what is generated when the query is run. 2010 Stored Procedure and Transactions If Stored Procedure is transactional then, it should roll back complete transactions when it encounters any errors. Well, that does not happen in this case, which proves that Stored Procedure does not only provide just the transactional feature to a batch of T-SQL. Generate Database Script for SQL Azure When talking about SQL Azure the most common complaint I hear is that the script generated from stand-along SQL Server database is not compatible with SQL Azure. This was true for some time for sure but not any more. If you have SQL Server 2008 R2 installed you can follow the guideline below to generate a script which is compatible with SQL Azure. Convert IN to EXISTS – Performance Talk It is NOT necessary that every time when IN is replaced by EXISTS it gives better performance. However, in our case listed above it does for sure give better performance. You can read about this subject in the associated blog post. Subquery or Join – Various Options – SQL Server Engine Knows the Best Every single time whenever there is a performance tuning exercise, I hear the conversation from developer where some prefer subquery and some prefer join. In this two part blog post, I explain the same in the detail with examples. Part 1 | Part 2 Merge Operations – Insert, Update, Delete in Single Execution MERGE is a new feature that provides an efficient way to do multiple DML operations. In earlier versions of SQL Server, we had to write separate statements to INSERT, UPDATE, or DELETE data based on certain conditions; however, at present, by using the MERGE statement, we can include the logic of such data changes in one statement that even checks when the data is matched and then just update it, and similarly, when the data is unmatched, it is inserted. 2011 Puzzle – Statistics are not updated but are Created Once Here is the quick scenario about my setup. Create Table Insert 1000 Records Check the Statistics Now insert 10 times more 10,000 indexes Check the Statistics – it will be NOT updated – WHY? Question to You – When to use Function and When to use Stored Procedure Personally, I believe that they are both different things - they cannot be compared. I can say, it will be like comparing apples and oranges. Each has its own unique use. However, they can be used interchangeably at many times and in real life (i.e., production environment). I have personally seen both of these being used interchangeably many times. This is the precise reason for asking this question. 2012 In year 2012 I had two interesting series ran on the blog. If there is no fun in learning, the learning becomes a burden. For the same reason, I had decided to build a three part quiz around SEQUENCE. The quiz was to identify the next value of the sequence. I encourage all of you to take part in this fun quiz. Guess the Next Value – Puzzle 1 Guess the Next Value – Puzzle 2 Guess the Next Value – Puzzle 3 Guess the Next Value – Puzzle 4 Simple Example to Configure Resource Governor – Introduction to Resource Governor Resource Governor is a feature which can manage SQL Server Workload and System Resource Consumption. We can limit the amount of CPU and memory consumption by limiting /governing /throttling on the SQL Server. If there are different workloads running on SQL Server and each of the workload needs different resources or when workloads are competing for resources with each other and affecting the performance of the whole server resource governor is a very important task. Tricks to Replace SELECT * with Column Names – SQL in Sixty Seconds #017 – Video Retrieves unnecessary columns and increases network traffic When a new columns are added views needs to be refreshed manually Leads to usage of sub-optimal execution plan Uses clustered index in most of the cases instead of using optimal index It is difficult to debug SQL SERVER – Load Generator – Free Tool From CodePlex The best part of this SQL Server Load Generator is that users can run multiple simultaneous queries again SQL Server using different login account and different application name. The interface of the tool is extremely easy to use and very intuitive as well. A Puzzle – Swap Value of Column Without Case Statement Let us assume there is a single column in the table called Gender. The challenge is to write a single update statement which will flip or swap the value in the column. For example if the value in the gender column is ‘male’ swap it with ‘female’ and if the value is ‘female’ swap it with ‘male’. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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Partner Blog Series: PwC Perspectives - "Is It Time for an Upgrade?"

- by Tanu Sood

Is your organization debating their next step with regard to Identity Management? While all the stakeholders are well aware that the one-size-fits-all doesn’t apply to identity management, just as true is the fact that no two identity management implementations are alike. Oracle’s recent release of Identity Governance Suite 11g Release 2 has innovative features such as a customizable user interface, shopping cart style request catalog and more. However, only a close look at the use cases can help you determine if and when an upgrade to the latest R2 release makes sense for your organization. This post will describe a few of the situations that PwC has helped our clients work through. “Should I be considering an upgrade?” If your organization has an existing identity management implementation, the questions below are a good start to assessing your current solution to see if you need to begin planning for an upgrade: Does the current solution scale and meet your projected identity management needs? Does the current solution have a customer-friendly user interface? Are you completely meeting your compliance objectives? Are you still using spreadsheets? Does the current solution have the features you need? Is your total cost of ownership in line with well-performing similar sized companies in your industry? Can your organization support your existing Identity solution? Is your current product based solution well positioned to support your organization's tactical and strategic direction? Existing Oracle IDM Customers: Several existing Oracle clients are looking to move to R2 in 2013. If your organization is on Sun Identity Manager (SIM) or Oracle Identity Manager (OIM) and if your current assessment suggests that you need to upgrade, you should strongly consider OIM 11gR2. Oracle provides upgrade paths to Oracle Identity Manager 11gR2 from SIM 7.x / 8.x as well as Oracle Identity Manager 10g / 11gR1. The following are some of the considerations for migration: Check the end of product support (for Sun or legacy OIM) schedule There are several new features available in R2 (including common Helpdesk scenarios, profiling of disconnected applications, increased scalability, custom connectors, browser-based UI configurations, portability of configurations during future upgrades, etc) Cost of ownership (for SIM customers)\ Customizations that need to be maintained during the upgrade Time/Cost to migrate now vs. waiting for next version If you are already on an older version of Oracle Identity Manager and actively maintaining your support contract with Oracle, you might be eligible for a free upgrade to OIM 11gR2. Check with your Oracle sales rep for more details. Existing IDM infrastructure in place: In the past year and half, we have seen a surge in IDM upgrades from non-Oracle infrastructure to Oracle. If your organization is looking to improve the end-user experience related to identity management functions, the shopping cart style access request model and browser based personalization features may come in handy. Additionally, organizations that have a large number of applications that include ecommerce, LDAP stores, databases, UNIX systems, mainframes as well as a high frequency of user identity changes and access requests will value the high scalability of the OIM reconciliation and provisioning engine. Furthermore, we have seen our clients like OIM's out of the box (OOB) support for multiple authoritative sources. For organizations looking to integrate applications that do not have an exposed API, the Generic Technology Connector framework supported by OIM will be helpful in quickly generating custom connector using OOB wizard. Similarly, organizations in need of not only flexible on-boarding of disconnected applications but also strict access management to these applications using approval flows will find the flexible disconnected application profiling feature an extremely useful tool that provides a high degree of time savings. Organizations looking to develop custom connectors for home grown or industry specific applications will likewise find that the Identity Connector Framework support in OIM allows them to build and test a custom connector independently before integrating it with OIM. Lastly, most of our clients considering an upgrade to OIM 11gR2 have also expressed interest in the browser based configuration feature that allows an administrator to quickly customize the user interface without adding any custom code. Better yet, code customizations, if any, made to the product are portable across the future upgrades which, is viewed as a big time and money saver by most of our clients. Below are some upgrade methodologies we adopt based on client priorities and the scale of implementation. For illustration purposes, we have assumed that the client is currently on Oracle Waveset (formerly Sun Identity Manager). Integrated Deployment: The integrated deployment is typically where a client wants to split the implementation to where their current IDM is continuing to handle the front end workflows and OIM takes over the back office operations incrementally. Once all the back office operations are moved completely to OIM, the front end workflows are migrated to OIM. Parallel Deployment: This deployment is typically done where there can be a distinct line drawn between which functionality the platforms are supporting. For example the current IDM implementation is handling the password reset functionality while OIM takes over the access provisioning and RBAC functions. Cutover Deployment: A cutover deployment is typically recommended where a client has smaller less complex implementations and it makes sense to leverage the migration tools to move them over immediately. What does this mean for YOU? There are many variables to consider when making upgrade decisions. For most customers, there is no ‘easy’ button. Organizations looking to upgrade or considering a new vendor should start by doing a mapping of their requirements with product features. The recommended approach is to take stock of both the short term and long term objectives, understand product features, future roadmap, maturity and level of commitment from the R&D and build the implementation plan accordingly. As we said, in the beginning, there is no one-size-fits-all with Identity Management. So, arm yourself with the knowledge, engage in industry discussions, bring in business stakeholders and start building your implementation roadmap. In the next post we will discuss the best practices on R2 implementations. We will be covering the Do's and Don't's and share our thoughts on making implementations successful. Meet the Writers: Dharma Padala is a Director in the Advisory Security practice within PwC. He has been implementing medium to large scale Identity Management solutions across multiple industries including utility, health care, entertainment, retail and financial sectors. Dharma has 14 years of experience in delivering IT solutions out of which he has been implementing Identity Management solutions for the past 8 years. Scott MacDonald is a Director in the Advisory Security practice within PwC. He has consulted for several clients across multiple industries including financial services, health care, automotive and retail. Scott has 10 years of experience in delivering Identity Management solutions. John Misczak is a member of the Advisory Security practice within PwC. He has experience implementing multiple Identity and Access Management solutions, specializing in Oracle Identity Manager and Business Process Engineering Language (BPEL). Praveen Krishna is a Manager in the Advisory Security practice within PwC. Over the last decade Praveen has helped clients plan, architect and implement Oracle identity solutions across diverse industries. His experience includes delivering security across diverse topics like network, infrastructure, application and data where he brings a holistic point of view to problem solving. Jenny (Xiao) Zhang is a member of the Advisory Security practice within PwC. She has consulted across multiple industries including financial services, entertainment and retail. Jenny has three years of experience in delivering IT solutions out of which she has been implementing Identity Management solutions for the past one and a half years.

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J2EE Applications, SPARC T4, Solaris Containers, and Resource Pools

- by user12620111

I've obtained a substantial performance improvement on a SPARC T4-2 Server running a J2EE Application Server Cluster by deploying the cluster members into Oracle Solaris Containers and binding those containers to cores of the SPARC T4 Processor. This is not a surprising result, in fact, it is consistent with other results that are available on the Internet. See the "references", below, for some examples. Nonetheless, here is a summary of my configuration and results. (1.0) Before deploying a J2EE Application Server Cluster into a virtualized environment, many decisions need to be made. I'm not claiming that all of the decisions that I have a made will work well for every environment. In fact, I'm not even claiming that all of the decisions are the best possible for my environment. I'm only claiming that of the small sample of configurations that I've tested, this is the one that is working best for me. Here are some of the decisions that needed to be made: (1.1) Which virtualization option? There are several virtualization options and isolation levels that are available. Options include: Hard partitions: Dynamic Domains on Sun SPARC Enterprise M-Series Servers Hypervisor based virtualization such as Oracle VM Server for SPARC (LDOMs) on SPARC T-Series Servers OS Virtualization using Oracle Solaris Containers Resource management tools in the Oracle Solaris OS to control the amount of resources an application receives, such as CPU cycles, physical memory, and network bandwidth. Oracle Solaris Containers provide the right level of isolation and flexibility for my environment. To borrow some words from my friends in marketing, "The SPARC T4 processor leverages the unique, no-cost virtualization capabilities of Oracle Solaris Zones" (1.2) How to associate Oracle Solaris Containers with resources? There are several options available to associate containers with resources, including (a) resource pool association (b) dedicated-cpu resources and (c) capped-cpu resources. I chose to create resource pools and associate them with the containers because I wanted explicit control over the cores and virtual processors. (1.3) Cluster Topology? Is it best to deploy (a) multiple application servers on one node, (b) one application server on multiple nodes, or (c) multiple application servers on multiple nodes? After a few quick tests, it appears that one application server per Oracle Solaris Container is a good solution. (1.4) Number of cluster members to deploy? I chose to deploy four big 64-bit application servers. I would like go back a test many 32-bit application servers, but that is left for another day. (2.0) Configuration tested. (2.1) I was using a SPARC T4-2 Server which has 2 CPU and 128 virtual processors. To understand the physical layout of the hardware on Solaris 10, I used the OpenSolaris psrinfo perl script available at http://hub.opensolaris.org/bin/download/Community+Group+performance/files/psrinfo.pl: test# ./psrinfo.pl -pv The physical processor has 8 cores and 64 virtual processors (0-63) The core has 8 virtual processors (0-7) The core has 8 virtual processors (8-15) The core has 8 virtual processors (16-23) The core has 8 virtual processors (24-31) The core has 8 virtual processors (32-39) The core has 8 virtual processors (40-47) The core has 8 virtual processors (48-55) The core has 8 virtual processors (56-63) SPARC-T4 (chipid 0, clock 2848 MHz) The physical processor has 8 cores and 64 virtual processors (64-127) The core has 8 virtual processors (64-71) The core has 8 virtual processors (72-79) The core has 8 virtual processors (80-87) The core has 8 virtual processors (88-95) The core has 8 virtual processors (96-103) The core has 8 virtual processors (104-111) The core has 8 virtual processors (112-119) The core has 8 virtual processors (120-127) SPARC-T4 (chipid 1, clock 2848 MHz) (2.2) The "before" test: without processor binding. I started with a 4-member cluster deployed into 4 Oracle Solaris Containers. Each container used a unique gigabit Ethernet port for HTTP traffic. The containers shared a 10 gigabit Ethernet port for JDBC traffic. (2.3) The "after" test: with processor binding. I ran one application server in the Global Zone and another application server in each of the three non-global zones (NGZ): (3.0) Configuration steps. The following steps need to be repeated for all three Oracle Solaris Containers. (3.1) Stop AppServers from the BUI. (3.2) Stop the NGZ. test# ssh test-z2 init 5 (3.3) Enable resource pools: test# svcadm enable pools (3.4) Create the resource pool: test# poolcfg -dc 'create pool pool-test-z2' (3.5) Create the processor set: test# poolcfg -dc 'create pset pset-test-z2' (3.6) Specify the maximum number of CPU's that may be addd to the processor set: test# poolcfg -dc 'modify pset pset-test-z2 (uint pset.max=32)' (3.7) bash syntax to add Virtual CPUs to the processor set: test# (( i = 64 )); while (( i < 96 )); do poolcfg -dc "transfer to pset pset-test-z2 (cpu $i)"; (( i = i + 1 )) ; done (3.8) Associate the resource pool with the processor set: test# poolcfg -dc 'associate pool pool-test-z2 (pset pset-test-z2)' (3.9) Tell the zone to use the resource pool that has been created: test# zonecfg -z test-z1 set pool=pool-test-z2 (3.10) Boot the Oracle Solaris Container test# zoneadm -z test-z2 boot (3.11) Save the configuration to /etc/pooladm.conf test# pooladm -s (4.0) Results. Using the resource pools improves both throughput and response time: (5.0) References: System Administration Guide: Oracle Solaris Containers-Resource Management and Oracle Solaris Zones Capitalizing on large numbers of processors with WebSphere Portal on Solaris WebSphere Application Server and T5440 (Dileep Kumar's Weblog) http://www.brendangregg.com/zones.html Reuters Market Data System, RMDS 6 Multiple Instances (Consolidated), Performance Test Results in Solaris, Containers/Zones Environment on Sun Blade X6270 by Amjad Khan, 2009.

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DTracing TCP congestion control

- by user12820842

In a previous post, I showed how we can use DTrace to probe TCP receive and send window events. TCP receive and send windows are in effect both about flow-controlling how much data can be received - the receive window reflects how much data the local TCP is prepared to receive, while the send window simply reflects the size of the receive window of the peer TCP. Both then represent flow control as imposed by the receiver. However, consider that without the sender imposing flow control, and a slow link to a peer, TCP will simply fill up it's window with sent segments. Dealing with multiple TCP implementations filling their peer TCP's receive windows in this manner, busy intermediate routers may drop some of these segments, leading to timeout and retransmission, which may again lead to drops. This is termed congestion, and TCP has multiple congestion control strategies. We can see that in this example, we need to have some way of adjusting how much data we send depending on how quickly we receive acknowledgement - if we get ACKs quickly, we can safely send more segments, but if acknowledgements come slowly, we should proceed with more caution. More generally, we need to implement flow control on the send side also. Slow Start and Congestion Avoidance From RFC2581, let's examine the relevant variables: "The congestion window (cwnd) is a sender-side limit on the amount of data the sender can transmit into the network before receiving an acknowledgment (ACK). Another state variable, the slow start threshold (ssthresh), is used to determine whether the slow start or congestion avoidance algorithm is used to control data transmission" Slow start is used to probe the network's ability to handle transmission bursts both when a connection is first created and when retransmission timers fire. The latter case is important, as the fact that we have effectively lost TCP data acts as a motivator for re-probing how much data the network can handle from the sending TCP. The congestion window (cwnd) is initialized to a relatively small value, generally a low multiple of the sending maximum segment size. When slow start kicks in, we will only send that number of bytes before waiting for acknowledgement. When acknowledgements are received, the congestion window is increased in size until cwnd reaches the slow start threshold ssthresh value. For most congestion control algorithms the window increases exponentially under slow start, assuming we receive acknowledgements. We send 1 segment, receive an ACK, increase the cwnd by 1 MSS to 2*MSS, send 2 segments, receive 2 ACKs, increase the cwnd by 2*MSS to 4*MSS, send 4 segments etc. When the congestion window exceeds the slow start threshold, congestion avoidance is used instead of slow start. During congestion avoidance, the congestion window is generally updated by one MSS for each round-trip-time as opposed to each ACK, and so cwnd growth is linear instead of exponential (we may receive multiple ACKs within a single RTT). This continues until congestion is detected. If a retransmit timer fires, congestion is assumed and the ssthresh value is reset. It is reset to a fraction of the number of bytes outstanding (unacknowledged) in the network. At the same time the congestion window is reset to a single max segment size. Thus, we initiate slow start until we start receiving acknowledgements again, at which point we can eventually flip over to congestion avoidance when cwnd ssthresh. Congestion control algorithms differ most in how they handle the other indication of congestion - duplicate ACKs. A duplicate ACK is a strong indication that data has been lost, since they often come from a receiver explicitly asking for a retransmission. In some cases, a duplicate ACK may be generated at the receiver as a result of packets arriving out-of-order, so it is sensible to wait for multiple duplicate ACKs before assuming packet loss rather than out-of-order delivery. This is termed fast retransmit (i.e. retransmit without waiting for the retransmission timer to expire). Note that on Oracle Solaris 11, the congestion control method used can be customized. See here for more details. In general, 3 or more duplicate ACKs indicate packet loss and should trigger fast retransmit . It's best not to revert to slow start in this case, as the fact that the receiver knew it was missing data suggests it has received data with a higher sequence number, so we know traffic is still flowing. Falling back to slow start would be excessive therefore, so fast recovery is used instead. Observing slow start and congestion avoidance The following script counts TCP segments sent when under slow start (cwnd ssthresh). #!/usr/sbin/dtrace -s #pragma D option quiet tcp:::connect-request / start[args[1]-cs_cid] == 0/ { start[args[1]-cs_cid] = 1; } tcp:::send / start[args[1]-cs_cid] == 1 && args[3]-tcps_cwnd tcps_cwnd_ssthresh / { @c["Slow start", args[2]-ip_daddr, args[4]-tcp_dport] = count(); } tcp:::send / start[args[1]-cs_cid] == 1 && args[3]-tcps_cwnd args[3]-tcps_cwnd_ssthresh / { @c["Congestion avoidance", args[2]-ip_daddr, args[4]-tcp_dport] = count(); } As we can see the script only works on connections initiated since it is started (using the start[] associative array with the connection ID as index to set whether it's a new connection (start[cid] = 1). From there we simply differentiate send events where cwnd ssthresh (congestion avoidance). Here's the output taken when I accessed a YouTube video (where rport is 80) and from an FTP session where I put a large file onto a remote system. # dtrace -s tcp_slow_start.d ^C ALGORITHM RADDR RPORT #SEG Slow start 10.153.125.222 20 6 Slow start 138.3.237.7 80 14 Slow start 10.153.125.222 21 18 Congestion avoidance 10.153.125.222 20 1164 We see that in the case of the YouTube video, slow start was exclusively used. Most of the segments we sent in that case were likely ACKs. Compare this case - where 14 segments were sent using slow start - to the FTP case, where only 6 segments were sent before we switched to congestion avoidance for 1164 segments. In the case of the FTP session, the FTP data on port 20 was predominantly sent with congestion avoidance in operation, while the FTP session relied exclusively on slow start. For the default congestion control algorithm - "newreno" - on Solaris 11, slow start will increase the cwnd by 1 MSS for every acknowledgement received, and by 1 MSS for each RTT in congestion avoidance mode. Different pluggable congestion control algorithms operate slightly differently. For example "highspeed" will update the slow start cwnd by the number of bytes ACKed rather than the MSS. And to finish, here's a neat oneliner to visually display the distribution of congestion window values for all TCP connections to a given remote port using a quantization. In this example, only port 80 is in use and we see the majority of cwnd values for that port are in the 4096-8191 range. # dtrace -n 'tcp:::send { @q[args[4]-tcp_dport] = quantize(args[3]-tcps_cwnd); }' dtrace: description 'tcp:::send ' matched 10 probes ^C 80 value ------------- Distribution ------------- count -1 | 0 0 |@@@@@@ 5 1 | 0 2 | 0 4 | 0 8 | 0 16 | 0 32 | 0 64 | 0 128 | 0 256 | 0 512 | 0 1024 | 0 2048 |@@@@@@@@@ 8 4096 |@@@@@@@@@@@@@@@@@@@@@@@@@@ 23 8192 | 0

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Master-slave vs. peer-to-peer archictecture: benefits and problems

- by Ashok_Ora

Normal 0 false false false EN-US X-NONE X-NONE Almost two decades ago, I was a member of a database development team that introduced adaptive locking. Locking, the most popular concurrency control technique in database systems, is pessimistic. Locking ensures that two or more conflicting operations on the same data item don’t “trample” on each other’s toes, resulting in data corruption. In a nutshell, here’s the issue we were trying to address. In everyday life, traffic lights serve the same purpose. They ensure that traffic flows smoothly and when everyone follows the rules, there are no accidents at intersections. As I mentioned earlier, the problem with typical locking protocols is that they are pessimistic. Regardless of whether there is another conflicting operation in the system or not, you have to hold a lock! Acquiring and releasing locks can be quite expensive, depending on how many objects the transaction touches. Every transaction has to pay this penalty. To use the earlier traffic light analogy, if you have ever waited at a red light in the middle of nowhere with no one on the road, wondering why you need to wait when there’s clearly no danger of a collision, you know what I mean. The adaptive locking scheme that we invented was able to minimize the number of locks that a transaction held, by detecting whether there were one or more transactions that needed conflicting eyou could get by without holding any lock at all. In many “well-behaved” workloads, there are few conflicts, so this optimization is a huge win. If, on the other hand, there are many concurrent, conflicting requests, the algorithm gracefully degrades to the “normal” behavior with minimal cost. We were able to reduce the number of lock requests per TPC-B transaction from 178 requests down to 2! Wow! This is a dramatic improvement in concurrency as well as transaction latency. The lesson from this exercise was that if you can identify the common scenario and optimize for that case so that only the uncommon scenarios are more expensive, you can make dramatic improvements in performance without sacrificing correctness. So how does this relate to the architecture and design of some of the modern NoSQL systems? NoSQL systems can be broadly classified as master-slave sharded, or peer-to-peer sharded systems. NoSQL systems with a peer-to-peer architecture have an interesting way of handling changes. Whenever an item is changed, the client (or an intermediary) propagates the changes synchronously or asynchronously to multiple copies (for availability) of the data. Since the change can be propagated asynchronously, during some interval in time, it will be the case that some copies have received the update, and others haven’t. What happens if someone tries to read the item during this interval? The client in a peer-to-peer system will fetch the same item from multiple copies and compare them to each other. If they’re all the same, then every copy that was queried has the same (and up-to-date) value of the data item, so all’s good. If not, then the system provides a mechanism to reconcile the discrepancy and to update stale copies. So what’s the problem with this? There are two major issues: First, IT’S HORRIBLY PESSIMISTIC because, in the common case, it is unlikely that the same data item will be updated and read from different locations at around the same time! For every read operation, you have to read from multiple copies. That’s a pretty expensive, especially if the data are stored in multiple geographically separate locations and network latencies are high. Second, if the copies are not all the same, the application has to reconcile the differences and propagate the correct value to the out-dated copies. This means that the application program has to handle discrepancies in the different versions of the data item and resolve the issue (which can further add to cost and operation latency). Resolving discrepancies is only one part of the problem. What if the same data item was updated independently on two different nodes (copies)? In that case, due to the asynchronous nature of change propagation, you might land up with different versions of the data item in different copies. In this case, the application program also has to resolve conflicts and then propagate the correct value to the copies that are out-dated or have incorrect versions. This can get really complicated. My hunch is that there are many peer-to-peer-based applications that don’t handle this correctly, and worse, don’t even know it. Imagine have 100s of millions of records in your database – how can you tell whether a particular data item is incorrect or out of date? And what price are you willing to pay for ensuring that the data can be trusted? Multiple network messages per read request? Discrepancy and conflict resolution logic in the application, and potentially, additional messages? All this overhead, when all you were trying to do was to read a data item. Wouldn’t it be simpler to avoid this problem in the first place? Master-slave architectures like the Oracle NoSQL Database handles this very elegantly. A change to a data item is always sent to the master copy. Consequently, the master copy always has the most current and authoritative version of the data item. The master is also responsible for propagating the change to the other copies (for availability and read scalability). Client drivers are aware of master copies and replicas, and client drivers are also aware of the “currency” of a replica. In other words, each NoSQL Database client knows how stale a replica is. This vastly simplifies the job of the application developer. If the application needs the most current version of the data item, the client driver will automatically route the request to the master copy. If the application is willing to tolerate some staleness of data (e.g. a version that is no more than 1 second out of date), the client can easily determine which replica (or set of replicas) can satisfy the request, and route the request to the most efficient copy. This results in a dramatic simplification in application logic and also minimizes network requests (the driver will only send the request to exactl the right replica, not many). So, back to my original point. A well designed and well architected system minimizes or eliminates unnecessary overhead and avoids pessimistic algorithms wherever possible in order to deliver a highly efficient and high performance system. If you’ve every programmed an Oracle NoSQL Database application, you’ll know the difference! /* 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-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; 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;}

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AdPrep logs show an LDAP error

- by Omar

What I am trying to do is transition our domain from Server 2003 Enterprise x32 to Server 2008 R2 Enterprise x64. Here is what I have done thus far. The 2003 server is a physical machine, the 2008 server is a virtual machine Built a virtual machine that has Server 2008 R2 Enterprise x64 and joined it to the domain as a domain member On the 2003 DC, Raised Domain Functional Level and Forest Functional Level to Windows Server 2003 On the 2003 DC, went into the registry and navigated to HKLM\SYSTEM\CurrentControlSet\Services\NTDS\Parameters and verified that the Schema Version is 30 On the 2003 DC, inserted the Windows Server 2008 Enterprise x32 Edition to copy over the adprep folder. This version is the only one that seemed to work On the 2003 DC, opened command prompt and went to adprep directory and ran adprep /forestprep , adprep /domainprep , and adprep /domainprep /gpprep On the 2008 server, Installed the Active Directory Domain Services role from Server Manager On the 2003 DC, went into the registry and navigated to HKLM\SYSTEM\CurrentControlSet\Services\NTDS\Parameters and verified that the Schema Version is now 44 When I go to run dcpromo on the 2008 server, I get a message that says: "To install a domain controller into this Active Directory forest, you must first prepare using adprep /forestprep" I went back to the 2003 DC server and went through the adprep logs and I came across this: Adprep was unable to modify the security descriptor on object CN=DomainControllerAuthentication,CN=Certificate Templates,CN=Public Key Services,CN=Services,CN=Configuration,DC=xeroxtoledo,DC=com. [Status/Consequence] ADPREP was unable to merge the existing security descriptor with the new access control entry (ACE). [User Action] Check the log file ADPrep.log in the C:\WINDOWS\debug\adprep\logs\20100327143517 directory for more information. Adprep encountered an LDAP error. *Error code: 0x20. Server extended error code: 0x208d, Server error message: 0000208D: NameErr: DSID-031001CD, problem 2001 (NO_OBJECT), data 0, best match of: 'CN=Certificate Templates,CN=Public Key Services,CN=Services,CN=Configuration,DC=xeroxtoledo,DC=com* In fact, I got three of these errors. The LDAP error is consistent with all three, but the top part where it says "Adprep was unable to modify the security descriptor on object" are different. They are the following: CN=DomainControllerAuthentication,CN=Certificate Templates,CN=Public Key Services,CN=Services,CN=Configuration,DC=xeroxtoledo,DC=com. CN=DirectoryEmailReplication,CN=Certificate Templates,CN=Public Key Services,CN=Services,CN=Configuration,DC=xeroxtoledo,DC=com. CN=KerberosAuthentication,CN=Certificate Templates,CN=Public Key Services,CN=Services,CN=Configuration,DC=xeroxtoledo,DC=com. The credentials I am using on the 2008 server when running dcpromo is my domain account. My account is part of the domain and enterprise admin groups. I've tried various quick fixes that I've came across through Google searches that include: Disabling AntiVirus on current DCs Pointing DNS on PDC to point to itself Changing the Schema Update Allowed key to 1 and tried rerunning adprep - when rerunning adprep, told me that Forest-wide information has already been updated Disabled Windows Firewall on the Server 2008 box On the 2003 DC, went to Domain Controller Security Policy Local Policies User Rights Assignment and added Domain Admins to the Enable computer and user accounts to be trusted for delegation policy setting Both our PDC and BDC are Global Catalog Servers. Not sure if this matters or not I ran the command netdom query fsmo and verified that the FSMO role holder is the current 2003 PDC I ran dcdiag /v on the 2003 PDC and the only thing that failed was Services. Dnscache Service is stopped on the PDC I even went as far as deleting the virtual machine and recreating it from scratch - no avail... Help :(

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windows 2003 server : can't join domain

- by phill

I originally tried to rejoin a computer to a network which led to a "cannot find domain" error. The username/password box don't even come up. some tests i ran: I can ping the server, however I can't ping the domain name domain1.local. nslookup can't find the domain either. It looks to the isp's dns instead of my own to resolve the local machines. So i go to the dns and run netdiag.exe and gives me this error. DNS test . . . . . . . . . . . . . : Failed [WARNING] Cannot find a primary authoritative DNS server for the name 'stmartinsrv.stmartin.local.'. [RCODE_SERVER_FAILURE] The name 'srv.domain1.local.' may not be registered in DNS. [WARNING] The DNS entries for this DC are not registered correctly on DNS se rver '68.94.156.1'. Please wait for 30 minutes for DNS server replication. [WARNING] The DNS entries for this DC are not registered correctly on DNS se rver '68.94.157.1'. Please wait for 30 minutes for DNS server replication. [FATAL] No DNS servers have the DNS records for this DC registered. Redir and Browser test . . . . . . : Passed List of NetBt transports currently bound to the Redir NetBT_Tcpip_{04BB0F6B-06AE-4D60-80C8-2A7A24C1D87B} The redir is bound to 1 NetBt transport. List of NetBt transports currently bound to the browser NetBT_Tcpip_{04BB0F6B-06AE-4D60-80C8-2A7A24C1D87B} The browser is bound to 1 NetBt transport. then running dcdiag C:\Program Files\Support Toolsdcdiag Domain Controller Diagnosis Performing initial setup: Done gathering initial info. Doing initial required tests Testing server: Default-First-Site-Name\SRV Starting test: Connectivity The host 1c99f63c-49ec-40db-b3d3-6265c00fbd3e._msdcs.domain1.local cou ld not be resolved to an IP address. Check the DNS server, DHCP, server name, etc Although the Guid DNS name (1c99f63c-49ec-40db-b3d3-6265c00fbd3e._msdcs.domain1.local) couldn't be resolved, the server name (srv.domain1.local) resolved to the IP address (192.168.1.21) and was pingable. Check that the IP address is registered correctly with the DNS server. ......................... SRV failed test Connectivity Doing primary tests Testing server: Default-First-Site-Name\SRV Skipping all tests, because server SRV is not responding to directory service requests Running partition tests on : ForestDnsZones Starting test: CrossRefValidation ......................... ForestDnsZones passed test CrossRefValidation Starting test: CheckSDRefDom ......................... ForestDnsZones passed test CheckSDRefDom Running partition tests on : DomainDnsZones Starting test: CrossRefValidation ......................... DomainDnsZones passed test CrossRefValidation Starting test: CheckSDRefDom ......................... DomainDnsZones passed test CheckSDRefDom Running partition tests on : Schema Starting test: CrossRefValidation ......................... Schema passed test CrossRefValidation Starting test: CheckSDRefDom ......................... Schema passed test CheckSDRefDom Running partition tests on : Configuration Starting test: CrossRefValidation ......................... Configuration passed test CrossRefValidation Starting test: CheckSDRefDom ......................... Configuration passed test CheckSDRefDom Running partition tests on : domain1 Starting test: CrossRefValidation ......................... domain1 passed test CrossRefValidation Starting test: CheckSDRefDom ......................... domain1 passed test CheckSDRefDom Running enterprise tests on : domain1.local Starting test: Intersite ......................... domain1.local passed test Intersite Starting test: FsmoCheck ......................... domain1.local passed test FsmoCheck from previous postings, I've tried adding the domain suffix to the nic ip properties to both the client machine and the dc server which didn't help. note: there is only one nic on the server any ideas? thanks in advance

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problem in run oracle server please help

- by rima

I used Oracle 11g, from few days ago I face below error: SQL*Plus: Release 11.2.0.1.0 Production on Thu Apr 7 07:33:19 2011 Copyright (c) 1982, 2010, Oracle. All rights reserved. Enter user-name: pentacms Enter password: ERROR: ORA-01033: ORACLE initialization or shutdown in progress Process ID: 0 Session ID: 0 Serial number: 0 Enter user-name: I try to solve the error, but it raised an other error, I try to open log file but I receive below error(last line) "ERROR at line 1: ORA-00600: internal error code, arguments: [kcratr_nab_less_than_odr], [1], [46], [32689], [32690], [], [], [], [], [], [], [] " please advice me, It's an emergency case. FIXED_TABLE_SEQUENCE ROW_WAIT_OBJ# ROW_WAIT_FILE# ROW_WAIT_BLOCK# ROW_WAIT_ROW# -------------------- ------------- -------------- --------------- ------------- TOP_LEVEL_CALL# LOGON_TIM LAST_CALL_ET PDM FAILOVER_TYPE FAILOVER_M FAI --------------- --------- ------------ --- ------------- ---------- --- RESOURCE_CONSUMER_GROUP PDML_STA PDDL_STA PQ_STATU -------------------------------- -------- -------- -------- CURRENT_QUEUE_DURATION ---------------------- CLIENT_IDENTIFIER BLOCKING_SE ---------------------------------------------------------------- ----------- BLOCKING_INSTANCE BLOCKING_SESSION FINAL_BLOCK FINAL_BLOCKING_INSTANCE ----------------- ---------------- ----------- ----------------------- FINAL_BLOCKING_SESSION SEQ# EVENT# ---------------------- ---------- ---------- EVENT ---------------------------------------------------------------- P1TEXT P1 ---------------------------------------------------------------- ---------- P1RAW ---------------- P2TEXT P2 ---------------------------------------------------------------- ---------- P2RAW ---------------- P3TEXT P3 ---------------------------------------------------------------- ---------- P3RAW WAIT_CLASS_ID WAIT_CLASS# ---------------- ------------- ----------- WAIT_CLASS WAIT_TIME ---------------------------------------------------------------- ---------- SECONDS_IN_WAIT STATE WAIT_TIME_MICRO TIME_REMAINING_MICRO --------------- ------------------- --------------- -------------------- TIME_SINCE_LAST_WAIT_MICRO -------------------------- SERVICE_NAME SQL_TRAC SQL_T ---------------------------------------------------------------- -------- ----- SQL_T SQL_TRACE_ SESSION_EDITION_ID CREATOR_ADDR CREATOR_SERIAL# ----- ---------- ------------------ ---------------- --------------- ECID ---------------------------------------------------------------- SYS$USERS DISABLED FALSE SADDR SID SERIAL# AUDSID PADDR USER# ---------------- ---------- ---------- ---------- ---------------- ---------- USERNAME COMMAND OWNERID TADDR ------------------------------ ---------- ---------- ---------------- LOCKWAIT STATUS SERVER SCHEMA# SCHEMANAME ---------------- -------- --------- ---------- ------------------------------ OSUSER PROCESS ------------------------------ ------------------------ MACHINE PORT ---------------------------------------------------------------- ---------- TERMINAL ---------------- PROGRAM TYPE ---------------------------------------------------------------- ---------- SQL_ADDRESS SQL_HASH_VALUE SQL_ID SQL_CHILD_NUMBER SQL_EXEC_ ---------------- -------------- ------------- ---------------- --------- SQL_EXEC_ID PREV_SQL_ADDR PREV_HASH_VALUE PREV_SQL_ID PREV_CHILD_NUMBER ----------- ---------------- --------------- ------------- ----------------- PREV_EXEC PREV_EXEC_ID PLSQL_ENTRY_OBJECT_ID PLSQL_ENTRY_SUBPROGRAM_ID --------- ------------ --------------------- ------------------------- PLSQL_OBJECT_ID PLSQL_SUBPROGRAM_ID --------------- ------------------- MODULE MODULE_HASH ------------------------------------------------ ----------- ACTION ACTION_HASH -------------------------------- ----------- CLIENT_INFO ---------------------------------------------------------------- FIXED_TABLE_SEQUENCE ROW_WAIT_OBJ# ROW_WAIT_FILE# ROW_WAIT_BLOCK# ROW_WAIT_ROW# -------------------- ------------- -------------- --------------- ------------- TOP_LEVEL_CALL# LOGON_TIM LAST_CALL_ET PDM FAILOVER_TYPE FAILOVER_M FAI --------------- --------- ------------ --- ------------- ---------- --- RESOURCE_CONSUMER_GROUP PDML_STA PDDL_STA PQ_STATU -------------------------------- -------- -------- -------- CURRENT_QUEUE_DURATION ---------------------- CLIENT_IDENTIFIER BLOCKING_SE ---------------------------------------------------------------- ----------- BLOCKING_INSTANCE BLOCKING_SESSION FINAL_BLOCK FINAL_BLOCKING_INSTANCE ----------------- ---------------- ----------- ----------------------- FINAL_BLOCKING_SESSION SEQ# EVENT# ---------------------- ---------- ---------- EVENT ---------------------------------------------------------------- P1TEXT P1 ---------------------------------------------------------------- ---------- P1RAW ---------------- P2TEXT P2 ---------------------------------------------------------------- ---------- P2RAW ---------------- P3TEXT P3 ---------------------------------------------------------------- ---------- P3RAW WAIT_CLASS_ID WAIT_CLASS# ---------------- ------------- ----------- WAIT_CLASS WAIT_TIME ---------------------------------------------------------------- ---------- SECONDS_IN_WAIT STATE WAIT_TIME_MICRO TIME_REMAINING_MICRO --------------- ------------------- --------------- -------------------- TIME_SINCE_LAST_WAIT_MICRO -------------------------- SERVICE_NAME SQL_TRAC SQL_T ---------------------------------------------------------------- -------- ----- SQL_T SQL_TRACE_ SESSION_EDITION_ID CREATOR_ADDR CREATOR_SERIAL# ----- ---------- ------------------ ---------------- --------------- ECID ---------------------------------------------------------------- FALSE FIRST EXEC 0 000007FF5D4D8D70 2 SADDR SID SERIAL# AUDSID PADDR USER# ---------------- ---------- ---------- ---------- ---------------- ---------- USERNAME COMMAND OWNERID TADDR ------------------------------ ---------- ---------- ---------------- LOCKWAIT STATUS SERVER SCHEMA# SCHEMANAME ---------------- -------- --------- ---------- ------------------------------ OSUSER PROCESS ------------------------------ ------------------------ MACHINE PORT ---------------------------------------------------------------- ---------- TERMINAL ---------------- PROGRAM TYPE ---------------------------------------------------------------- ---------- SQL_ADDRESS SQL_HASH_VALUE SQL_ID SQL_CHILD_NUMBER SQL_EXEC_ ---------------- -------------- ------------- ---------------- --------- SQL_EXEC_ID PREV_SQL_ADDR PREV_HASH_VALUE PREV_SQL_ID PREV_CHILD_NUMBER ----------- ---------------- --------------- ------------- ----------------- PREV_EXEC PREV_EXEC_ID PLSQL_ENTRY_OBJECT_ID PLSQL_ENTRY_SUBPROGRAM_ID --------- ------------ --------------------- ------------------------- PLSQL_OBJECT_ID PLSQL_SUBPROGRAM_ID --------------- ------------------- MODULE MODULE_HASH ------------------------------------------------ ----------- ACTION ACTION_HASH -------------------------------- ----------- CLIENT_INFO ---------------------------------------------------------------- FIXED_TABLE_SEQUENCE ROW_WAIT_OBJ# ROW_WAIT_FILE# ROW_WAIT_BLOCK# ROW_WAIT_ROW# -------------------- ------------- -------------- --------------- ------------- TOP_LEVEL_CALL# LOGON_TIM LAST_CALL_ET PDM FAILOVER_TYPE FAILOVER_M FAI --------------- --------- ------------ --- ------------- ---------- --- RESOURCE_CONSUMER_GROUP PDML_STA PDDL_STA PQ_STATU -------------------------------- -------- -------- -------- CURRENT_QUEUE_DURATION ---------------------- CLIENT_IDENTIFIER BLOCKING_SE ---------------------------------------------------------------- ----------- BLOCKING_INSTANCE BLOCKING_SESSION FINAL_BLOCK FINAL_BLOCKING_INSTANCE ----------------- ---------------- ----------- ----------------------- FINAL_BLOCKING_SESSION SEQ# EVENT# ---------------------- ---------- ---------- EVENT ---------------------------------------------------------------- P1TEXT P1 ---------------------------------------------------------------- ---------- P1RAW ---------------- P2TEXT P2 ---------------------------------------------------------------- ---------- P2RAW ---------------- P3TEXT P3 ---------------------------------------------------------------- ---------- P3RAW WAIT_CLASS_ID WAIT_CLASS# ---------------- ------------- ----------- WAIT_CLASS WAIT_TIME ---------------------------------------------------------------- ---------- SECONDS_IN_WAIT STATE WAIT_TIME_MICRO TIME_REMAINING_MICRO --------------- ------------------- --------------- -------------------- TIME_SINCE_LAST_WAIT_MICRO -------------------------- SERVICE_NAME SQL_TRAC SQL_T ---------------------------------------------------------------- -------- ----- SQL_T SQL_TRACE_ SESSION_EDITION_ID CREATOR_ADDR CREATOR_SERIAL# ----- ---------- ------------------ ---------------- --------------- ECID ---------------------------------------------------------------- SADDR SID SERIAL# AUDSID PADDR USER# ---------------- ---------- ---------- ---------- ---------------- ---------- USERNAME COMMAND OWNERID TADDR ------------------------------ ---------- ---------- ---------------- LOCKWAIT STATUS SERVER SCHEMA# SCHEMANAME ---------------- -------- --------- ---------- ------------------------------ OSUSER PROCESS ------------------------------ ------------------------ MACHINE PORT ---------------------------------------------------------------- ---------- TERMINAL ---------------- PROGRAM TYPE ---------------------------------------------------------------- ---------- SQL_ADDRESS SQL_HASH_VALUE SQL_ID SQL_CHILD_NUMBER SQL_EXEC_ ---------------- -------------- ------------- ---------------- --------- SQL_EXEC_ID PREV_SQL_ADDR PREV_HASH_VALUE PREV_SQL_ID PREV_CHILD_NUMBER ----------- ---------------- --------------- ------------- ----------------- PREV_EXEC PREV_EXEC_ID PLSQL_ENTRY_OBJECT_ID PLSQL_ENTRY_SUBPROGRAM_ID --------- ------------ --------------------- ------------------------- PLSQL_OBJECT_ID PLSQL_SUBPROGRAM_ID --------------- ------------------- MODULE MODULE_HASH ------------------------------------------------ ----------- ACTION ACTION_HASH -------------------------------- ----------- CLIENT_INFO ---------------------------------------------------------------- FIXED_TABLE_SEQUENCE ROW_WAIT_OBJ# ROW_WAIT_FILE# ROW_WAIT_BLOCK# ROW_WAIT_ROW# -------------------- ------------- -------------- --------------- ------------- TOP_LEVEL_CALL# LOGON_TIM LAST_CALL_ET PDM FAILOVER_TYPE FAILOVER_M FAI --------------- --------- ------------ --- ------------- ---------- --- RESOURCE_CONSUMER_GROUP PDML_STA PDDL_STA PQ_STATU -------------------------------- -------- -------- -------- CURRENT_QUEUE_DURATION ---------------------- CLIENT_IDENTIFIER BLOCKING_SE ---------------------------------------------------------------- ----------- BLOCKING_INSTANCE BLOCKING_SESSION FINAL_BLOCK FINAL_BLOCKING_INSTANCE ----------------- ---------------- ----------- ----------------------- FINAL_BLOCKING_SESSION SEQ# EVENT# ---------------------- ---------- ---------- EVENT ---------------------------------------------------------------- P1TEXT P1 ---------------------------------------------------------------- ---------- P1RAW ---------------- P2TEXT P2 ---------------------------------------------------------------- ---------- P2RAW ---------------- P3TEXT P3 ---------------------------------------------------------------- ---------- P3RAW WAIT_CLASS_ID WAIT_CLASS# ---------------- ------------- ----------- WAIT_CLASS WAIT_TIME ---------------------------------------------------------------- ---------- SECONDS_IN_WAIT STATE WAIT_TIME_MICRO TIME_REMAINING_MICRO --------------- ------------------- --------------- -------------------- TIME_SINCE_LAST_WAIT_MICRO -------------------------- SERVICE_NAME SQL_TRAC SQL_T ---------------------------------------------------------------- -------- ----- SQL_T SQL_TRACE_ SESSION_EDITION_ID CREATOR_ADDR CREATOR_SERIAL# ----- ---------- ------------------ ---------------- --------------- ECID ---------------------------------------------------------------- 16 rows selected. SQL> desc dba_user; ERROR: ORA-04043: object dba_user does not exist SQL> desc dba_users; ERROR: ORA-04043: object dba_users does not exist SQL> desc v$user; ERROR: ORA-04043: object v$user does not exist SQL> desc v$users ERROR: ORA-04043: object v$users does not exist SQL> seleect * from dba_users; SP2-0734: unknown command beginning "seleect * ..." - rest of line ignored. SQL> select * from dba_users; select * from dba_users * ERROR at line 1: ORA-01219: database not open: queries allowed on fixed tables/views only SQL> alter database open; alter database open * ERROR at line 1: ORA-00600: internal error code, arguments: [kcratr_nab_less_than_odr], [1], [46], [32689], [32690], [], [], [], [], [], [], [] SQL> alter database mount; alter database mount * ERROR at line 1: ORA-01100: database already mounted SQL> alter database mount;

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