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  • LINQ Normalizing data

    - by Brennan Mann
    I am using an OMS that stores up to three line items per record in the database. Below is an example of an order containing five line items. Order Header Order Detail Prod 1 Prod 2 Prod 3 Order Detail Prod 4 Prod 5 One order header record and two detail records. My goal is have a one to one relation for details records(i.e., one detail record per line item). In the past, I used an UNION ALL SQL statement to extract the data. Is there a better approcach to this problem using LINQ? Below is my first attempt at using LINQ. Any feedback, suggestions or recommendations would greatly be appreciated. For what I have read, an UNION statement can tax the process? var orderdetail = (from o in context.ORDERSUBHEADs select new { edpNo = o.EDPNOS_001, price = o.EXTPRICES_001, qty = o.ITEMQTYS_001 } ).Union(from o in context.ORDERSUBHEADs select new { edpNo = o.EDPNOS_002, price = o.EXTPRICES_002, qty = o.ITEMQTYS_002 } ).Union(from o in context.ORDERSUBHEADs select new { edpNo = o.EDPNOS_003, price = o.EXTPRICES_003, qty = o.ITEMQTYS_003 });

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  • Improve mysql JDBC insert call

    - by richs
    i have a legacy Java system that every time it gets an order it makes a JDBC call to a stored procedure for each field in the order. Generally the stored procedure will get called 20 to 30 times for each order. The store procedure is just doing an insert into a table for each field. i need to improve the performance of this operation. one thought i had was to create an insert query string that does multiple inserts in one JDBC call. MySql supports a multiple insert string. INSERT INTO PersonAge (name, age) VALUES ('Helen', 24), ('Katrina', 21), ('Samia', 22), ('Hui Ling', 25), ('Yumie', 29) This has the advantage of only requiring one JDBC call per order. Any other ideas on how to improve performance?

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  • Non-linear regression models in PostgreSQL using R

    - by Dave Jarvis
    Background I have climate data (temperature, precipitation, snow depth) for all of Canada between 1900 and 2009. I have written a basic website and the simplest page allows users to choose category and city. They then get back a very simple report (without the parameters and calculations section): The primary purpose of the web application is to provide a simple user interface so that the general public can explore the data in meaningful ways. (A list of numbers is not meaningful to the general public, nor is a website that provides too many inputs.) The secondary purpose of the application is to provide climatologists and other scientists with deeper ways to view the data. (Using too many inputs, of course.) Tool Set The database is PostgreSQL with R (mostly) installed. The reports are written using iReport and generated using JasperReports. Poor Model Choice Currently, a linear regression model is applied against annual averages of daily data. The linear regression model is calculated within a PostgreSQL function as follows: SELECT regr_slope( amount, year_taken ), regr_intercept( amount, year_taken ), corr( amount, year_taken ) FROM temp_regression INTO STRICT slope, intercept, correlation; The results are returned to JasperReports using: SELECT year_taken, amount, year_taken * slope + intercept, slope, intercept, correlation, total_measurements INTO result; JasperReports calls into PostgreSQL using the following parameterized analysis function: SELECT year_taken, amount, measurements, regression_line, slope, intercept, correlation, total_measurements, execute_time FROM climate.analysis( $P{CityId}, $P{Elevation1}, $P{Elevation2}, $P{Radius}, $P{CategoryId}, $P{Year1}, $P{Year2} ) ORDER BY year_taken This is not an optimal solution because it gives the false impression that the climate is changing at a slow, but steady rate. Questions Using functions that take two parameters (e.g., year [X] and amount [Y]), such as PostgreSQL's regr_slope: What is a better regression model to apply? What CPAN-R packages provide such models? (Installable, ideally, using apt-get.) How can the R functions be called within a PostgreSQL function? If no such functions exist: What parameters should I try to obtain for functions that will produce the desired fit? How would you recommend showing the best fit curve? Keep in mind that this is a web app for use by the general public. If the only way to analyse the data is from an R shell, then the purpose has been defeated. (I know this is not the case for most R functions I have looked at so far.) Thank you!

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  • Release another user's lock obtained with sp_getapplock on SQL Server

    - by joshperry
    We have a system that uses sp_getapplock to create an exclusive mutex any time someone opens an order in the GUI. This is used to prevent multiple people from making changes to an order simultaneously. Sometimes people will open an order and go home, leaving it open. This effectively blocks anyone from being able to make changes to the order. I then get emails, calls and end up doing a kill <spid> in enterprise manager. Obviously I've gotten sick of this and want to make a quick self-service webform. The main problem I've run into is that kill requires sysadmin privileges, which I do not want to give to the user that the our website runs as. I have tried sp_releaseapplock but this doesn't let you release another user's lock (even when calling it as a sysadmin). So, finally my question; does anyone know of an alternative method to release a lock that was obtained by another user using sp_getapplock?

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  • Heroku Push Problem part 2 - Postgresql - PGError Relations does not exist - Ruby on Rails

    - by bgadoci
    Ok so got through my last problem with the difference between Postgresql and SQLite and seems like Heroku is telling me I have another one. I am new to ruby and rails so a lot of this stuff I can't decipher at first. Looking for a little direction here. The error message and PostsController Index are below. I checked my routes.rb file and all seems well there but I could be missing something. I will post if you need. Processing PostsController#index (for 99.7.50.140 at 2010-04-23 15:19:22) [GET] ActiveRecord::StatementInvalid (PGError: ERROR: relation "tags" does not exist : SELECT a.attname, format_type(a.atttypid, a.atttypmod), d.adsrc, a.attnotnull FROM pg_attribute a LEFT JOIN pg_attrdef d ON a.attrelid = d.adrelid AND a.attnum = d.adnum WHERE a.attrelid = '"tags"'::regclass AND a.attnum > 0 AND NOT a.attisdropped ORDER BY a.attnum ): PostsController#index def index @tag_counts = Tag.count(:group => :tag_name, :order => 'count_all DESC', :limit => 20) conditions, joins = {}, :votes @ugtag_counts = Ugtag.count(:group => :ugctag_name, :order => 'count_all DESC', :limit => 20) conditions, joins = {}, :votes @vote_counts = Vote.count(:group => :post_title, :order => 'count_all DESC', :limit => 20) conditions, joins = {}, :votes unless(params[:tag_name] || "").empty? conditions = ["tags.tag_name = ? ", params[:tag_name]] joins = [:tags, :votes] end @posts=Post.paginate( :select => "posts.*, count(*) as vote_total", :joins => joins, :conditions=> conditions, :group => "votes.post_id, posts.id ", :order => "created_at DESC", :page => params[:page], :per_page => 5) @popular_posts=Post.paginate( :select => "posts.*, count(*) as vote_total", :joins => joins, :conditions=> conditions, :group => "votes.post_id, posts.id", :order => "vote_total DESC", :page => params[:page], :per_page => 3) respond_to do |format| format.html # index.html.erb format.xml { render :xml => @posts } format.json { render :json => @posts } format.atom end end

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  • please clarify some aspects of AJAX with ASP.NET web forms for a beginner

    - by citrus
    Im familiar with asp.net web forms. I would now like to move on to writing web applications that use AJAX. I would like to get to the stage where I can create an app: that has "edit in place" (no page reload) where i can reorder images using drag and drop (also saves the order to DB) that has google like search suggestions while typing on the fly 1)So do I need to learn how to use AJAX.net and Jquery(my JS library of choice)? Can I make do using only AJAX.net or only Jquery? 2)As far a I know, Jquery will allow me to perform client side manipulations/actions and AJAX.net is the part that will allow me to connect some of my actions to the Server. EG. if I wanted to re-order elements using drag and drop, I would use Jquery, but in order to save the result of the re-order to the DB I would have to use AJAX.net correct? 2a)So In order to learn how to do the above Im thinking I should first learn Jquery so I know how to manipulate/ select elements, and then I can lean how to save these changes to the DB. 3)I searched the books titled "ASP.net AJAX in action" and ASP.net 3.5 AJAX, both of these books did not contain any references to "Jquery". Is this because they may be using a different JS library, or perhaps the book focuses on the AJAX user controls? I just found it confusing that 2 popular AJAX books dont make any reference to Jquery. Thanks for any help.

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  • Eclipselink read complex oject model in an ordered way

    - by Raven
    Hi, I need to read a complex model in an ordered way with eclipselink. The order is mandantory because it is a huge database and I want to have an output of a small portion of the database in a jface tableview. Trying to reorder it in the loading/quering thread takes too long and ordering it in the LabelProvider blocks the UI thread too much time, so I thought if Eclipselink could be used that way, that the database will order it, it might give me the performance I need. Unfortunately the object model can not be changed :-( The model is something like: @SuppressWarnings("serial") @Entity public class Thing implements Serializable { @Id @GeneratedValue(strategy = GenerationType.TABLE) private int id; private String name; @OneToMany(cascade=CascadeType.ALL) @PrivateOwned private List<Property> properties = new ArrayList<Property>(); ... // getter and setter following here } public class Property implements Serializable { @Id @GeneratedValue(strategy = GenerationType.TABLE) private int id; @OneToOne private Item item; private String value; ... // getter and setter following here } public class Item implements Serializable { @Id @GeneratedValue(strategy = GenerationType.TABLE) private int id; private String name; .... // getter and setter following here } // Code end In the table view the y-axis is more or less created with the query Query q = em.createQuery("SELECT m FROM Thing m ORDER BY m.name ASC"); using the "name" attribute from the Thing objects as label. In the table view the x-axis is more or less created with the query Query q = em.createQuery("SELECT m FROM Item m ORDER BY m.name ASC"); using the "name" attribute from the Item objects as label. Each cell has the value Things.getProperties().get[x].getValue() Unfortunately the list "properties" is not ordered, so the combination of cell value and x-axis column number (x) is not necessarily correct. Therefore I need to order the list "properties" in the same way as I ordered the labeling of the x-axis. And exactly this is the thing I dont know how it is done. So querying for the Thing objects should return the list "properties" "ORDER BY name ASC" but of the "Item"s objects. My ideas are something like having a query with two JOINs. Joing Things with Property and with Item but somehow I was unable to get it to work yet. Thank you for your help and your ideas to solve this riddle.

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  • Subsonic 3 ActiveRecord nested select for NotIn bug?

    - by Junto
    I have the following Subsonic 3.0 query, which contains a nested NotIn query: public List<Order> GetRandomOrdersForNoReason(int shopId, int typeId) { // build query var q = new SubSonic.Query.Select().Top("1") .From("Order") .Where("ShopId") .IsEqualTo(shopId) .And(OrderTable.CustomerId).NotIn( new Subsonic.Query.Select("CustomerId") .From("Customer") .Where("TypeId") .IsNotEqualTo(typeId)) .OrderDesc("NewId()"); // Output query Debug.WriteLine(q.ToString()); // returned typed list return q.ExecuteTypedList<Order>(); } The internal query appears to be incorrect: SELECT TOP 1 * FROM [Order] WHERE ShopId = @0 AND CustomerId NOT IN (SELECT CustomerId FROM [Customer] WHERE TypeId = @0) ORDER BY NewId() ASC You'll notice that both parameters are @0. I'm assuming that the parameters are enumerated (starting at zero), for each "new" Select query. However, in this case where the two Select queries are nested, I would have expected the output to have two parameters named @0 and @1. My query is based on one that Rob Conery gave on his blog as a preview of the "Pakala" query tool that became Subsonic 3. His example was: int records = new Select(Northwind.Product.Schema) .Where("productid") .In( new Select("productid").From(Northwind.Product.Schema) .Where("categoryid").IsEqualTo(5) ) .GetRecordCount(); Has anyone else seen this behavior? Is it a bug, or is this an error or my part? Since I'm new to Subsonic I'm guessing that this probably programmer error on my part but I'd like confirmation if possible.

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  • Get list of Unique many-to-many records from a queryset

    - by rsp
    My models: class Order(models.Model): ordered_by = models.ForeignKey(User) reasons = models.ManyToManyField(Reason) class Reason(models.Model): description = models.CharField() Basically a user creates an order and gives reasons for that order. ie, john has two orders (one for pencils because he is out AND because he doesn't like his current stock. a second order for pens because he is out). I want to print a list out of all reasons a user has placed his orders. So under john, it should print "he is out", "he doesn't like his current stock"; those two lines only. If I simply select all of john's orders, iterate through them and print out their "reasons" it'll print "he is out", "he doesn't like his current stock" and then "he is out" again. I don't want these duplicate values. How do I select a list of his reasons for ALL his orders so that the list has all unique rows?

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  • myth about factory pattern

    - by leiz
    This has bothered me for awhile, and I have no clues if this is a myth. It seems that a factory pattern can ease the pain of adding a dependency for a class. For example, in a book, it has something like this Suppose that you have a class named Order. Initially it did not depend on anything. Therefore you didn't bother using a factory to create Order objects and you just used plain new to instantiate the objects. However, you now have a requirement that Order has to be created in association with a Customer. There are million places you need to change to add this extra parameter. If only you had de?ned a factory for the Order class, you would have met the new requirement without the same pain. How is this not same pain as adding an extra parameter to the constructor? I mean you would still need to provide an extra argument for the factory and that is also used by million places, right?

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  • MS SQL datetime precision problem

    - by Nailuj
    I have a situation where two persons might work on the same order (stored in an MS SQL database) from two different computers. To prevent data loss in the case where one would save his copy of the order first, and then a little later the second would save his copy and overwrite the first, I've added a check against the lastSaved field (datetime) before saving. The code looks roughly like this: private bool orderIsChangedByOtherUser(Order localOrderCopy) { // Look up fresh version of the order from the DB Order databaseOrder = orderService.GetByOrderId(localOrderCopy.Id); if (databaseOrder != null && databaseOrder.LastSaved > localOrderCopy.LastSaved) { return true; } else { return false; } } This works for most of the time, but I have found one small bug. If orderIsChangedByOtherUser returns false, the local copy will have its lastSaved updated to the current time and then be persisted to the database. The value of lastSaved in the local copy and the DB should now be the same. However, if orderIsChangedByOtherUser is run again, it sometimes returns true even though no other user has made changes to the DB. When debugging in Visual Studio, databaseOrder.LastSaved and localOrderCopy.LastSaved appear to have the same value, but when looking closer they some times differ by a few milliseconds. I found this article with a short notice on the millisecond precision for datetime in SQL: Another problem is that SQL Server stores DATETIME with a precision of 3.33 milliseconds (0. 00333 seconds). The solution I could think of for this problem, is to compare the two datetimes and consider them equal if they differ by less than say 10 milliseconds. My question to you is then: are there any better/safer ways to compare two datetime values in MS SQL to see if they are exactly the same?

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  • problem with iterate over java.util.Map using "JSF" OR JSTL TAGS

    - by New-To-Java
    I'm using Richfaces jsf and I want to iterate over an Map<Object,Object>. I see many examples on sun forums and other sites but in my case it doesn't work ! here is my xhtml code : <c:forEach items="#{order.customOptions}" var="option"> <h:outputText value="this text does not print"/> <h:outputText value="#{option.value.name}" /> <h:outputText value="#{option.value.key}" /> </c:forEach> and the "order" object is of type "Order". "customOptios" is of type Map<CustomOption,CustomOptionValue> and when I create an javascript alert on to print '#{order.customeOptions}' it's content is true. but it's not even enter in c:forEach loop. please heeeeelp me :(

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  • How do I install ASP.NET MVC 2 Futures?

    - by Zack Peterson
    I want to use the DataAnnotations.DisplayAttribute.Order property to arrange my fields when using the DisplayForModel and EditorForModel methods. Related question: Does the DataAnnotations.DisplayAttribute.Order property not work with ASP.NET MVC 2? I think that I need to use the ASP.NET MVC 2 Futures. But I can't get it to work. How do I install ASP.NET MVC 2 Futures? Why are my fields still out of order?

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  • Linq join with an inner collection

    - by bronze
    Hi, I am trying a LINQ to Object query on 2 collections Customer.Orders Branches.Pending.Orders (Collection within a collection) I want to output each branch which is yet to deliver any order of the customer. var match = from order in customer.Orders join branch in Branches on order equals branch.Pending.Orders select branch; This does not work, I get : The type of one of the expressions in the join clause is incorrect. Type inference failed in the call to 'GroupJoin'. From my search, I think this is because Order or collection of Orders does not implement equals. If this query worked, it will still be wrong, as it will return a branch if the customer's and pending orders match exactly. I want a result if any of the order matches. I am learning Linq, and looking for a approach to address such issues, rather than the solution itself. I would have done this in SQL like this; SELECT b.branch_name from Customers c, Branches b, Orders o WHERE c.customer_id = o.customer_id AND o.branch_id = b.branch_id AND c.customer_id = 'my customer' AND o.order_status = 'pending'

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  • How to get SQL Function run a different query and return value from either query?

    - by RoguePlanetoid
    I need a function, but cannot seem to get it quite right, I have looked at examples here and elsewhere and cannot seem to get this just right, I need an optional item to be included in my query, I have this query (which works): SELECT TOP 100 PERCENT SKU, Description, LEN(CONVERT(VARCHAR (1000),Description)) AS LenDesc FROM tblItem WHERE Title = @Title AND Manufacturer = @Manufacturer ORDER BY LenDesc DESC This works within a Function, however the Manufacturer is Optional for this search - which is to find the description of a similar item, if none is present, the other query is: SELECT TOP 100 PERCENT SKU, Description, LEN(CONVERT(VARCHAR (1000),Description)) AS LenDesc FROM tblItem WHERE Title = @Title ORDER BY LenDesc DESC Which is missing the Manufacturer, how to I get my function to use either query based on the Manufacturer Value being present or not. The reason is I will have a function which first checks an SKU for a Description, if it is not present - it uses this method to get a Description from a Similar Product, then updates the product being added with the similar product's description. Here is the function so far: ALTER FUNCTION [dbo].[GetDescriptionByTitleManufacturer] ( @Title varchar(400), @Manufacturer varchar(160) ) RETURNS TABLE AS RETURN ( SELECT TOP 100 PERCENT SKU, Description, LEN(CONVERT(VARCHAR (1000),Description)) AS LenDesc FROM tblItem WHERE Title = @Title AND Manufacturer = @Manufacturer ORDER BY LenDesc DESC ) I've tried adding BEGINs and IF...ELSEs but get errors or syntax problems each way I try it, I want to be able to do something like this pseudo-function (which does not work): ALTER FUNCTION [dbo].[GetDescriptionByTitleManufacturer] ( @Title varchar(400), @Manufacturer varchar(160) ) RETURNS TABLE AS BEGIN IF (@Manufacturer = Null) RETURN ( SELECT TOP 100 PERCENT SKU, Description, LEN(CONVERT(VARCHAR (1000),Description)) AS LenDesc FROM tblItem WHERE Title = @Title ORDER BY LenDesc DESC ) ELSE RETURN ( SELECT TOP 100 PERCENT SKU, Description, LEN(CONVERT(VARCHAR (1000),Description)) AS LenDesc FROM tblItem WHERE Title = @Title AND Manufacturer = @Manufacturer ORDER BY LenDesc DESC ) END

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  • Mysql ninja tricks

    - by alexn
    Hi, what are your mysql ninja tricks? What features are extra special? I'm starting with ORDER BY FIELD which enables you to sort in a particular order, like this: SELECT url FROM customer ORDER BY FIELD(customer.priority, 1, 2, 3, 0) Features like this is hard to find in the mysql documentation. Bring it!

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  • Benchmarking MySQL Replication with Multi-Threaded Slaves

    - by Mat Keep
    0 0 1 1145 6530 Homework 54 15 7660 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:EN-US;} The objective of this benchmark is to measure the performance improvement achieved when enabling the Multi-Threaded Slave enhancement delivered as a part MySQL 5.6. As the results demonstrate, Multi-Threaded Slaves delivers 5x higher replication performance based on a configuration with 10 databases/schemas. For real-world deployments, higher replication performance directly translates to: · Improved consistency of reads from slaves (i.e. reduced risk of reading "stale" data) · Reduced risk of data loss should the master fail before replicating all events in its binary log (binlog) The multi-threaded slave splits processing between worker threads based on schema, allowing updates to be applied in parallel, rather than sequentially. This delivers benefits to those workloads that isolate application data using databases - e.g. multi-tenant systems deployed in cloud environments. Multi-Threaded Slaves are just one of many enhancements to replication previewed as part of the MySQL 5.6 Development Release, which include: · Global Transaction Identifiers coupled with MySQL utilities for automatic failover / switchover and slave promotion · Crash Safe Slaves and Binlog · Optimized Row Based Replication · Replication Event Checksums · Time Delayed Replication These and many more are discussed in the “MySQL 5.6 Replication: Enabling the Next Generation of Web & Cloud Services” Developer Zone article  Back to the benchmark - details are as follows. Environment The test environment consisted of two Linux servers: · one running the replication master · one running the replication slave. Only the slave was involved in the actual measurements, and was based on the following configuration: - Hardware: Oracle Sun Fire X4170 M2 Server - CPU: 2 sockets, 6 cores with hyper-threading, 2930 MHz. - OS: 64-bit Oracle Enterprise Linux 6.1 - Memory: 48 GB Test Procedure Initial Setup: Two MySQL servers were started on two different hosts, configured as replication master and slave. 10 sysbench schemas were created, each with a single table: CREATE TABLE `sbtest` (    `id` int(10) unsigned NOT NULL AUTO_INCREMENT,    `k` int(10) unsigned NOT NULL DEFAULT '0',    `c` char(120) NOT NULL DEFAULT '',    `pad` char(60) NOT NULL DEFAULT '',    PRIMARY KEY (`id`),    KEY `k` (`k`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 10,000 rows were inserted in each of the 10 tables, for a total of 100,000 rows. When the inserts had replicated to the slave, the slave threads were stopped. The slave data directory was copied to a backup location and the slave threads position in the master binlog noted. 10 sysbench clients, each configured with 10 threads, were spawned at the same time to generate a random schema load against each of the 10 schemas on the master. Each sysbench client executed 10,000 "update key" statements: UPDATE sbtest set k=k+1 WHERE id = <random row> In total, this generated 100,000 update statements to later replicate during the test itself. Test Methodology: The number of slave workers to test with was configured using: SET GLOBAL slave_parallel_workers=<workers> Then the slave IO thread was started and the test waited for all the update queries to be copied over to the relay log on the slave. The benchmark clock was started and then the slave SQL thread was started. The test waited for the slave SQL thread to finish executing the 100k update queries, doing "select master_pos_wait()". When master_pos_wait() returned, the benchmark clock was stopped and the duration calculated. The calculated duration from the benchmark clock should be close to the time it took for the SQL thread to execute the 100,000 update queries. The 100k queries divided by this duration gave the benchmark metric, reported as Queries Per Second (QPS). Test Reset: The test-reset cycle was implemented as follows: · the slave was stopped · the slave data directory replaced with the previous backup · the slave restarted with the slave threads replication pointer repositioned to the point before the update queries in the binlog. The test could then be repeated with identical set of queries but a different number of slave worker threads, enabling a fair comparison. The Test-Reset cycle was repeated 3 times for 0-24 number of workers and the QPS metric calculated and averaged for each worker count. MySQL Configuration The relevant configuration settings used for MySQL are as follows: binlog-format=STATEMENT relay-log-info-repository=TABLE master-info-repository=TABLE As described in the test procedure, the slave_parallel_workers setting was modified as part of the test logic. The consequence of changing this setting is: 0 worker threads:    - current (i.e. single threaded) sequential mode    - 1 x IO thread and 1 x SQL thread    - SQL thread both reads and executes the events 1 worker thread:    - sequential mode    - 1 x IO thread, 1 x Coordinator SQL thread and 1 x Worker thread    - coordinator reads the event and hands it to the worker who executes 2+ worker threads:    - parallel execution    - 1 x IO thread, 1 x Coordinator SQL thread and 2+ Worker threads    - coordinator reads events and hands them to the workers who execute them Results Figure 1 below shows that Multi-Threaded Slaves deliver ~5x higher replication performance when configured with 10 worker threads, with the load evenly distributed across our 10 x schemas. This result is compared to the current replication implementation which is based on a single SQL thread only (i.e. zero worker threads). Figure 1: 5x Higher Performance with Multi-Threaded Slaves The following figure shows more detailed results, with QPS sampled and reported as the worker threads are incremented. The raw numbers behind this graph are reported in the Appendix section of this post. Figure 2: Detailed Results As the results above show, the configuration does not scale noticably from 5 to 9 worker threads. When configured with 10 worker threads however, scalability increases significantly. The conclusion therefore is that it is desirable to configure the same number of worker threads as schemas. Other conclusions from the results: · Running with 1 worker compared to zero workers just introduces overhead without the benefit of parallel execution. · As expected, having more workers than schemas adds no visible benefit. Aside from what is shown in the results above, testing also demonstrated that the following settings had a very positive effect on slave performance: relay-log-info-repository=TABLE master-info-repository=TABLE For 5+ workers, it was up to 2.3 times as fast to run with TABLE compared to FILE. Conclusion As the results demonstrate, Multi-Threaded Slaves deliver significant performance increases to MySQL replication when handling multiple schemas. This, and the other replication enhancements introduced in MySQL 5.6 are fully available for you to download and evaluate now from the MySQL Developer site (select Development Release tab). You can learn more about MySQL 5.6 from the documentation  Please don’t hesitate to comment on this or other replication blogs with feedback and questions. Appendix – Detailed Results

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  • Re-indexing table; update with from

    - by David Thorisson
    The query says it all, I can't find out the right syntax without without using a for..next UPDATE Webtree SET Webtree.Sorting=w2.Sorting FROM ( SELECT BranchID, CASE WHEN @Index>=ROW_NUMBER() OVER(ORDER BY Sorting ASC) THEN ROW_NUMBER() OVER(ORDER BY Sorting ASC) ELSE ROW_NUMBER() OVER(ORDER BY Sorting ASC)+1 END AS Sorting FROM Webtree w2 WHERE w2.ParentID=@ParentID ) WHERE Webtree.BranchID=w2.BranchID

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  • How to add if statement in SQL ?

    - by shin
    I have a following MySQL with two parameters, $catname and $limit=1. And it is working fine. SELECT P.*, C.Name AS CatName FROM omc_product AS P LEFT JOIN omc_category AS C ON C.id = P.category_id WHERE C.Name = '$catname' AND p.status = 'active' ORDER BY RAND() LIMIT 0, $limit Now I want to add another parameter $order. $order can be either ODER BY RAND() or ORDER BY product_order in the table omc_product. Could anyone tell me how to write this query please? Thanks in advance.

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  • SQL: Need help with query construction.

    - by Geeknidas
    Hi Guys, I am relatively new with sql and I need some help with some basic query construction. Problem: To retrieve the number of orders and the customer id from a table based on a set of parameters. I want to write a query to figure out the number of orders under each customer (Column: Customerid) along with the CustomerID where the number of orders should be greater or equal to 10 and the status of the order should be Active. Moreover, I also want to know the first transaction date of an order belonging to each customerid. Table Description: product_orders Orderid CustomerId Transaction_date Status ------- ---------- ---------------- ------- 1 23 2-2-10 Active 2 22 2-3-10 Active 3 23 2-3-10 Deleted 4 23 2-3-10 Active Query that I have written: select count(*), customerid from product_orders where status = 'Active' GROUP BY customerid ORDER BY customerid; The above statement gives me the sum of all order under a customer id but does not fulfil the condition of atleast 10 orders. I donot know how to display the first transaction date along with the order under a customerid (status: could be active or delelted doesn't matter) Ideal solutions should look like: Total Orders CustomerID Transaction Date (the first transaction date) ------------ ---------- ---------------- 11 23 1-2-10 Thanks in advance. I hope you guys would be kind enough to stop by and help me out. Cheers, Leonidas

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  • ASP.NET MVC: Triggering an action before posting to Paypal payment gateway

    - by ajbeaven
    I'm in the middle of developing an e-commerce site that is using Paypal as it's payment gateway. All I want to do is run some code before the user heads off to Paypal to pay for their order, but I have no idea how to do it. The user should click a submit button, changes are made (in this case, the status of the order), and then the user is redirected to the payment gateway. Eg: [AcceptVerbs(HttpVerbs.Post)] public ActionResult GoToPaypal(FormCollection collection) { //change order status //send user to paypal where they pay for their order } So my question is how do you do application stuff and then redirect to paypal's payment gateway? Example HTML and C# would be lovely :)

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  • Need some help understanding this problem about maximizing graph connectivity

    - by Legend
    I was wondering if someone could help me understand this problem. I prepared a small diagram because it is much easier to explain it visually. Problem I am trying to solve: 1. Constructing the dependency graph Given the connectivity of the graph and a metric that determines how well a node depends on the other, order the dependencies. For instance, I could put in a few rules saying that node 3 depends on node 4 node 2 depends on node 3 node 3 depends on node 5 But because the final rule is not "valuable" (again based on the same metric), I will not add the rule to my system. 2. Execute the request order Once I built a dependency graph, execute the list in an order that maximizes the final connectivity. I am not sure if this is a really a problem but I somehow have a feeling that there might exist more than one order in which case, it is required to choose the best order. First and foremost, I am wondering if I constructed the problem correctly and if I should be aware of any corner cases. Secondly, is there a closely related algorithm that I can look at? Currently, I am thinking of something like Feedback Arc Set or the Secretary Problem but I am a little confused at the moment. Any suggestions? PS: I am a little confused about the problem myself so please don't flame on me for that. If any clarifications are needed, I will try to update the question.

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  • LIKE query for DateTime in NHibernate

    - by Anry
    For a column of type varchar I could write such a query: public IList<Order> GetByName(string orderName) { using (ISession session = NHibernateHelper.OpenSession()) { return session.CreateCriteria<Order>(). Add(Restrictions.Like("Name", string.Format("%{0}%", orderName))). List<Order>(); } } How do I write a similar LIKE-query for a column that has type datetime? public IList<Order> GetByDateTime(DateTime dateTime) { using (ISession session = NHibernateHelper.OpenSession()) { return //LIKE-query } } That is, if the method is passed the date and part-time (eg "25.03.2010 19"), then displays all orders are carried out in this period of time.

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  • Remove another user's lock obtained with sp_getapplock on SQL Server

    - by joshperry
    We have a system that uses sp_getapplock to create an exclusive mutex any time someone opens an order in the GUI. This is used to prevent multiple people from making changes to an order simultaneously. Sometimes people will open an order and go home, leaving it open. This effectively blocks anyone from being able to make changes to the order. I then get emails, calls and end up doing a kill <spid> in enterprise manager. Obviously I've gotten sick of this and want to make a quick self-service webform. The main problem I've run into is that kill requires sysadmin privileges, which I do not want to give to the user that the our website runs as. I have tried sp_releaseapplock but this doesn't let you release another user's lock (even when calling it as a sysadmin). So, finally my question; does anyone know of an alternative method to release a lock that was obtained by another user using sp_getapplock?

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