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  • Query performance difference pl/sql forall insert and plain SQL insert

    - by user289429
    We have been using temporary table to store intermediate results in pl/sql Stored procedure. Could anyone tell if there is a performance difference between doing bulk collect insert through pl/sql and a plain SQL insert. Insert into or Cursor for open cursor fetch cursor bulk collect into collection Use FORALL to perform insert Which of the above 2 options is better to insert huge amount of temporary data?

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  • JUnit Rule TemporaryFolder

    - by Jeff Storey
    I'm creating a TemporaryFolder using the @Rule annotation in JUnit 4.7. I've tried to create a new folder that is a child of the temp folder using tempFolder.newFolder("someFolder") in the @Before (setup) method of my test. It seems as though the temporary folder gets initialized after the setup method runs, meaning I can't use the temporary folder in the setup method. Is this correct (and predictable) behavior? thanks, Jeff

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  • PHP: How to get creation date from uploaded file?

    - by Haemp
    Problem: I want to determine the original file creation time from a file uploaded to my server via PHP. My understanding is that the file is copied from the client to a temporary file on my server, which then is referenced in the $_FILES var. The temporary file is of course of no use because it was just created. Is there any way I could get the creation date from the clients original file? Thanks

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  • Question regarding to value/reference type of events

    - by Petr
    Hi, On the MSDN, I have found following: public event EventHandler<MyEventArgs> SampleEvent; public void DemoEvent(string val) { // Copy to a temporary variable to be thread-safe. EventHandler<MyEventArgs> temp = SampleEvent; if (temp != null) temp(this, new MyEventArgs(val)); } I do not understand, "copy to temporary variable", isnt it reference type?

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  • SQL swap field values

    - by Silence
    I have a SQL table (MYSQL 4.0 to be precise) composed of the following : int no (primary) int field1 int field2 I would like to swap the values of field1 with the values of field2 and vice-versa. Ex.: 1;2.5;3.76 becomes 1;3.76;2.5 I need a swapping temporary variable of some sort. But I don't think I can use something like Set @var1 = field1 inside my update statement. And I don't think altering the table to add a temporary column is my best best either.

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  • How can I save shell output to a variable in LaTeX?

    - by Frank
    I need to be able to execute a shell command through LaTeX [*] and have the resulting output available for use later on in the form of a LaTeX 'variable' (e.g., via a subsequent \newcommand command). If necessary a temporary file could be used to hold the output, although I would like to avoid this. I have been able to use \immediate\write18 to invoke a bash command before, but this was only used to write to a temporary file. [*] I realise that the -shell-escape flag must be set for this to be allowed

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  • Is this correct about ajax POST?

    - by Tommy
    Could you confirm I understand this correctly. Using POST, the file specified in xmlhttp.open("GET","ajax_test.asp",true); will not be cached (sent to \Temporary Internet Files) ? It will stay on the server only? If this is true, is the updated html file after calling ajax POST, being updated in the \Temporary Internet Files ? Am I missing any other important information of this mechanism? Thank You.

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  • Sorting Algorithms

    - by MarkPearl
    General Every time I go back to university I find myself wading through sorting algorithms and their implementation in C++. Up to now I haven’t really appreciated their true value. However as I discovered this last week with Dictionaries in C# – having a knowledge of some basic programming principles can greatly improve the performance of a system and make one think twice about how to tackle a problem. I’m going to cover briefly in this post the following: Selection Sort Insertion Sort Shellsort Quicksort Mergesort Heapsort (not complete) Selection Sort Array based selection sort is a simple approach to sorting an unsorted array. Simply put, it repeats two basic steps to achieve a sorted collection. It starts with a collection of data and repeatedly parses it, each time sorting out one element and reducing the size of the next iteration of parsed data by one. So the first iteration would go something like this… Go through the entire array of data and find the lowest value Place the value at the front of the array The second iteration would go something like this… Go through the array from position two (position one has already been sorted with the smallest value) and find the next lowest value in the array. Place the value at the second position in the array This process would be completed until the entire array had been sorted. A positive about selection sort is that it does not make many item movements. In fact, in a worst case scenario every items is only moved once. Selection sort is however a comparison intensive sort. If you had 10 items in a collection, just to parse the collection you would have 10+9+8+7+6+5+4+3+2=54 comparisons to sort regardless of how sorted the collection was to start with. If you think about it, if you applied selection sort to a collection already sorted, you would still perform relatively the same number of iterations as if it was not sorted at all. Many of the following algorithms try and reduce the number of comparisons if the list is already sorted – leaving one with a best case and worst case scenario for comparisons. Likewise different approaches have different levels of item movement. Depending on what is more expensive, one may give priority to one approach compared to another based on what is more expensive, a comparison or a item move. Insertion Sort Insertion sort tries to reduce the number of key comparisons it performs compared to selection sort by not “doing anything” if things are sorted. Assume you had an collection of numbers in the following order… 10 18 25 30 23 17 45 35 There are 8 elements in the list. If we were to start at the front of the list – 10 18 25 & 30 are already sorted. Element 5 (23) however is smaller than element 4 (30) and so needs to be repositioned. We do this by copying the value at element 5 to a temporary holder, and then begin shifting the elements before it up one. So… Element 5 would be copied to a temporary holder 10 18 25 30 23 17 45 35 – T 23 Element 4 would shift to Element 5 10 18 25 30 30 17 45 35 – T 23 Element 3 would shift to Element 4 10 18 25 25 30 17 45 35 – T 23 Element 2 (18) is smaller than the temporary holder so we put the temporary holder value into Element 3. 10 18 23 25 30 17 45 35 – T 23   We now have a sorted list up to element 6. And so we would repeat the same process by moving element 6 to a temporary value and then shifting everything up by one from element 2 to element 5. As you can see, one major setback for this technique is the shifting values up one – this is because up to now we have been considering the collection to be an array. If however the collection was a linked list, we would not need to shift values up, but merely remove the link from the unsorted value and “reinsert” it in a sorted position. Which would reduce the number of transactions performed on the collection. So.. Insertion sort seems to perform better than selection sort – however an implementation is slightly more complicated. This is typical with most sorting algorithms – generally, greater performance leads to greater complexity. Also, insertion sort performs better if a collection of data is already sorted. If for instance you were handed a sorted collection of size n, then only n number of comparisons would need to be performed to verify that it is sorted. It’s important to note that insertion sort (array based) performs a number item moves – every time an item is “out of place” several items before it get shifted up. Shellsort – Diminishing Increment Sort So up to now we have covered Selection Sort & Insertion Sort. Selection Sort makes many comparisons and insertion sort (with an array) has the potential of making many item movements. Shellsort is an approach that takes the normal insertion sort and tries to reduce the number of item movements. In Shellsort, elements in a collection are viewed as sub-collections of a particular size. Each sub-collection is sorted so that the elements that are far apart move closer to their final position. Suppose we had a collection of 15 elements… 10 20 15 45 36 48 7 60 18 50 2 19 43 30 55 First we may view the collection as 7 sub-collections and sort each sublist, lets say at intervals of 7 10 60 55 – 20 18 – 15 50 – 45 2 – 36 19 – 48 43 – 7 30 10 55 60 – 18 20 – 15 50 – 2 45 – 19 36 – 43 48 – 7 30 (Sorted) We then sort each sublist at a smaller inter – lets say 4 10 55 60 18 – 20 15 50 2 – 45 19 36 43 – 48 7 30 10 18 55 60 – 2 15 20 50 – 19 36 43 45 – 7 30 48 (Sorted) We then sort elements at a distance of 1 (i.e. we apply a normal insertion sort) 10 18 55 60 2 15 20 50 19 36 43 45 7 30 48 2 7 10 15 18 19 20 30 36 43 45 48 50 55 (Sorted) The important thing with shellsort is deciding on the increment sequence of each sub-collection. From what I can tell, there isn’t any definitive method and depending on the order of your elements, different increment sequences may perform better than others. There are however certain increment sequences that you may want to avoid. An even based increment sequence (e.g. 2 4 8 16 32 …) should typically be avoided because it does not allow for even elements to be compared with odd elements until the final sort phase – which in a way would negate many of the benefits of using sub-collections. The performance on the number of comparisons and item movements of Shellsort is hard to determine, however it is considered to be considerably better than the normal insertion sort. Quicksort Quicksort uses a divide and conquer approach to sort a collection of items. The collection is divided into two sub-collections – and the two sub-collections are sorted and combined into one list in such a way that the combined list is sorted. The algorithm is in general pseudo code below… Divide the collection into two sub-collections Quicksort the lower sub-collection Quicksort the upper sub-collection Combine the lower & upper sub-collection together As hinted at above, quicksort uses recursion in its implementation. The real trick with quicksort is to get the lower and upper sub-collections to be of equal size. The size of a sub-collection is determined by what value the pivot is. Once a pivot is determined, one would partition to sub-collections and then repeat the process on each sub collection until you reach the base case. With quicksort, the work is done when dividing the sub-collections into lower & upper collections. The actual combining of the lower & upper sub-collections at the end is relatively simple since every element in the lower sub-collection is smaller than the smallest element in the upper sub-collection. Mergesort With quicksort, the average-case complexity was O(nlog2n) however the worst case complexity was still O(N*N). Mergesort improves on quicksort by always having a complexity of O(nlog2n) regardless of the best or worst case. So how does it do this? Mergesort makes use of the divide and conquer approach to partition a collection into two sub-collections. It then sorts each sub-collection and combines the sorted sub-collections into one sorted collection. The general algorithm for mergesort is as follows… Divide the collection into two sub-collections Mergesort the first sub-collection Mergesort the second sub-collection Merge the first sub-collection and the second sub-collection As you can see.. it still pretty much looks like quicksort – so lets see where it differs… Firstly, mergesort differs from quicksort in how it partitions the sub-collections. Instead of having a pivot – merge sort partitions each sub-collection based on size so that the first and second sub-collection of relatively the same size. This dividing keeps getting repeated until the sub-collections are the size of a single element. If a sub-collection is one element in size – it is now sorted! So the trick is how do we put all these sub-collections together so that they maintain their sorted order. Sorted sub-collections are merged into a sorted collection by comparing the elements of the sub-collection and then adjusting the sorted collection. Lets have a look at a few examples… Assume 2 sub-collections with 1 element each 10 & 20 Compare the first element of the first sub-collection with the first element of the second sub-collection. Take the smallest of the two and place it as the first element in the sorted collection. In this scenario 10 is smaller than 20 so 10 is taken from sub-collection 1 leaving that sub-collection empty, which means by default the next smallest element is in sub-collection 2 (20). So the sorted collection would be 10 20 Lets assume 2 sub-collections with 2 elements each 10 20 & 15 19 So… again we would Compare 10 with 15 – 10 is the winner so we add it to our sorted collection (10) leaving us with 20 & 15 19 Compare 20 with 15 – 15 is the winner so we add it to our sorted collection (10 15) leaving us with 20 & 19 Compare 20 with 19 – 19 is the winner so we add it to our sorted collection (10 15 19) leaving us with 20 & _ 20 is by default the winner so our sorted collection is 10 15 19 20. Make sense? Heapsort (still needs to be completed) So by now I am tired of sorting algorithms and trying to remember why they were so important. I think every year I go through this stuff I wonder to myself why are we made to learn about selection sort and insertion sort if they are so bad – why didn’t we just skip to Mergesort & Quicksort. I guess the only explanation I have for this is that sometimes you learn things so that you can implement them in future – and other times you learn things so that you know it isn’t the best way of implementing things and that you don’t need to implement it in future. Anyhow… luckily this is going to be the last one of my sorts for today. The first step in heapsort is to convert a collection of data into a heap. After the data is converted into a heap, sorting begins… So what is the definition of a heap? If we have to convert a collection of data into a heap, how do we know when it is a heap and when it is not? The definition of a heap is as follows: A heap is a list in which each element contains a key, such that the key in the element at position k in the list is at least as large as the key in the element at position 2k +1 (if it exists) and 2k + 2 (if it exists). Does that make sense? At first glance I’m thinking what the heck??? But then after re-reading my notes I see that we are doing something different – up to now we have really looked at data as an array or sequential collection of data that we need to sort – a heap represents data in a slightly different way – although the data is stored in a sequential collection, for a sequential collection of data to be in a valid heap – it is “semi sorted”. Let me try and explain a bit further with an example… Example 1 of Potential Heap Data Assume we had a collection of numbers as follows 1[1] 2[2] 3[3] 4[4] 5[5] 6[6] For this to be a valid heap element with value of 1 at position [1] needs to be greater or equal to the element at position [3] (2k +1) and position [4] (2k +2). So in the above example, the collection of numbers is not in a valid heap. Example 2 of Potential Heap Data Lets look at another collection of numbers as follows 6[1] 5[2] 4[3] 3[4] 2[5] 1[6] Is this a valid heap? Well… element with the value 6 at position 1 must be greater or equal to the element at position [3] and position [4]. Is 6 > 4 and 6 > 3? Yes it is. Lets look at element 5 as position 2. It must be greater than the values at [4] & [5]. Is 5 > 3 and 5 > 2? Yes it is. If you continued to examine this second collection of data you would find that it is in a valid heap based on the definition of a heap.

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  • How to add new filters to CAML queries in SharePoint 2007

    - by uruit
    Normal 0 21 false false false ES-UY X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; 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-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} One flexibility SharePoint has is CAML (Collaborative Application Markup Language). CAML it’s a markup language like html that allows developers to do queries against SharePoint lists, it’s syntax is very easy to understand and it allows to add logical conditions like Where, Contains, And, Or, etc, just like a SQL Query. For one of our projects we have the need to do a filter on SharePoint views, the problem here is that the view it’s a list containing a CAML Query with the filters the view may have, so in order to filter the view that’s already been filtered before, we need to append our filters to the existing CAML Query. That’s not a trivial task because the where statement in a CAML Query it’s like this: <Where>   <And>     <Filter1 />     <Filter2 />   </And> </Where> If we want to add a new logical operator, like an OR it’s not just as simple as to append the OR expression like the following example: <Where>   <And>     <Filter1 />     <Filter2 />   </And>   <Or>     <Filter3 />   </Or> </Where> But instead the correct query would be: <Where>   <Or>     <And>       <Filter1 />       <Filter2 />     </And>     <Filter3 />   </Or> </Where> Notice that the <Filter# /> tags are for explanation purpose only. In order to solve this problem we created a simple component, it has a method that receives the current query (could be an empty query also) and appends the expression you want to that query. Example: string currentQuery = @“ <Where>    <And>     <Contains><FieldRef Name='Title' /><Value Type='Text'>A</Value></Contains>     <Contains><FieldRef Name='Title' /><Value Type='Text'>B</Value></Contains>   </And> </Where>”; currentQuery = CAMLQueryBuilder.AppendQuery(     currentQuery,     “<Contains><FieldRef Name='Title' /><Value Type='Text'>C</Value></Contains>”,     CAMLQueryBuilder.Operators.Or); The fist parameter this function receives it’s the actual query, the second it’s the filter you want to add, and the third it’s the logical operator, so basically in this query we want all the items that the title contains: the character A and B or the ones that contains the character C. The result query is: <Where>   <Or>      <And>       <Contains><FieldRef Name='Title' /><Value Type='Text'>A</Value></Contains>       <Contains><FieldRef Name='Title' /><Value Type='Text'>B</Value></Contains>     </And>     <Contains><FieldRef Name='Title' /><Value Type='Text'>C</Value></Contains>   </Or> </Where>     The code:   First of all we have an enumerator inside the CAMLQueryBuilder class that has the two possible Options And, Or. public enum Operators { And, Or }   Then we have the main method that’s the one that performs the append of the filters. public static string AppendQuery(string containerQuery, string logicalExpression, Operators logicalOperator){   In this method the first we do is create a new XmlDocument and wrap the current query (that may be empty) with a “<Query></Query>” tag, because the query that comes with the view doesn’t have a root element and the XmlDocument must be a well formatted xml.   XmlDocument queryDoc = new XmlDocument(); queryDoc.LoadXml("<Query>" + containerQuery + "</Query>");   The next step is to create a new XmlDocument containing the logical expression that has the filter needed.   XmlDocument logicalExpressionDoc = new XmlDocument(); logicalExpressionDoc.LoadXml("<root>" + logicalExpression + "</root>"); In these next four lines we extract the expression from the recently created XmlDocument and create an XmlElement.                  XmlElement expressionElTemp = (XmlElement)logicalExpressionDoc.SelectSingleNode("/root/*"); XmlElement expressionEl = queryDoc.CreateElement(expressionElTemp.Name); expressionEl.InnerXml = expressionElTemp.InnerXml;   Below are the main steps in the component logic. The first “if” checks if the actual query doesn’t contains a “Where” clause. In case there’s no “Where” we add it and append the expression.   In case that there’s already a “Where” clause, we get the entire statement that’s inside the “Where” and reorder the query removing and appending elements to form the correct query, that will finally filter the list.   XmlElement whereEl; if (!containerQuery.Contains("Where")) { queryDoc.FirstChild.AppendChild(queryDoc.CreateElement("Where")); queryDoc.SelectSingleNode("/Query/Where").AppendChild(expressionEl); } else { whereEl = (XmlElement)queryDoc.SelectSingleNode("/Query/Where"); if (!containerQuery.Contains("<And>") &&                 !containerQuery.Contains("<Or>"))        {              XmlElement operatorEl = queryDoc.CreateElement(GetName(logicalOperator)); XmlElement existingExpression = (XmlElement)whereEl.SelectSingleNode("/Query/Where/*"); whereEl.RemoveChild(existingExpression);                 operatorEl.AppendChild(existingExpression);               operatorEl.AppendChild(expressionEl);                 whereEl.AppendChild(operatorEl);        }        else        {              XmlElement operatorEl = queryDoc.CreateElement(GetName(logicalOperator)); XmlElement existingOperator = (XmlElement)whereEl.SelectSingleNode("/Query/Where/*");                 whereEl.RemoveChild(existingOperator);               operatorEl.AppendChild(existingOperator);               operatorEl.AppendChild(expressionEl);                 whereEl.AppendChild(operatorEl);         }  }  return queryDoc.FirstChild.InnerXml }     Finally the GetName method converts the Enum option to his string equivalent.   private static string GetName(Operators logicalOperator) {       return Enum.GetName(typeof(Operators), logicalOperator); }        Normal 0 21 false false false ES-UY X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; 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-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Normal 0 21 false false false ES-UY X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; 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-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} This component helped our team a lot using SharePoint 2007 and modifying the queries, but now in SharePoint 2010; that wouldn’t be needed because of the incorporation of LINQ to SharePoint. This new feature enables the developers to do typed queries against SharePoint lists without the need of writing any CAML code.  But there is still much development to the 2007 version, so I hope this information is useful for other members.  Post Normal 0 21 false false false ES-UY X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-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:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;} written by Sebastian Rodriguez - Portals and Collaboration Solutions @ UruIT

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  • Simple GET operation with JSON data in ADF Mobile

    - by PadmajaBhat
    Usecase: This sample uses a RESTful service which contains a GET method that fetches employee details for an employee with given employee ID along with other methods. The data is fetched in JSON format. This RESTful service is then invoked via ADF Mobile and the JSON data thus obtained is parsed and rendered in mobile in a table. Prerequisite: Download JDev build JDEVADF_11.1.2.4.0_GENERIC_130421.1600.6436.1 or higher with mobile support.  Steps: Run EmployeeService.java in JSONService.zip. This is a simple service with a method, getEmpById(id) that takes employee ID as parameter and produces employee details in JSON format. Copy the target URL generated on running this service. The target URL will be as shown below: http://127.0.0.1:7101/JSONService-Project1-context-root/jersey/project1 Now, let us invoke this service in our mobile application. For this, create an ADF Mobile application.  Name the application JSON_SearchByEmpID and finish the wizard. Now, let us create a connection to our service. To do this, we create a URL Connection. Invoke new gallery wizard on ApplicationController project.  Select URL Connection option. In the Create URL Connection window, enter connection name as ‘conn’. For URL endpoint, supply the URL you copied earlier on running the service. Remember to use your system IP instead of localhost. Test the connection and click OK. At this point, a connection to the REST service has been created. Since JSON data is not supported directly in WSDC wizard, we need to invoke the operation through Java code using RestServiceAdapter. For this, in the ApplicationController project, create a Java class called ‘EmployeeDC’. We will be creating DC from this class. Add the following code to the newly created class to invoke the getEmpById method. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 public Employee fetchEmpDetails(){ RestServiceAdapter restServiceAdapter = Model.createRestServiceAdapter(); restServiceAdapter.clearRequestProperties(); restServiceAdapter.setConnectionName("conn"); //URL connection created with this name restServiceAdapter.setRequestType(RestServiceAdapter.REQUEST_TYPE_GET); restServiceAdapter.addRequestProperty("Content-Type", "application/json"); restServiceAdapter.addRequestProperty("Accept", "application/json; charset=UTF-8"); restServiceAdapter.setRetryLimit(0); restServiceAdapter.setRequestURI("/getById/"+inputEmpID); String response = ""; JSONBeanSerializationHelper jsonHelper = new JSONBeanSerializationHelper(); try { response = restServiceAdapter.send(""); //Invoke the GET operation System.out.println("Response received!"); Employee responseObject = (Employee) jsonHelper.fromJSON(Employee.class, response); return responseObject; } catch (Exception e) { } return null; } Here, in lines 2 to 9, we create the RestServiceAdapter and set various properties required to invoke the web service. At line 4, we are pointing to the connection ‘conn’ created previously. Since we want to invoke getEmpById method of the service, which is defined by the URL http://IP:7101/REST_Sanity_JSON-Project1-context-root/resources/project1/getById/{id} we are updating the request URI to point to this URI at line 9. inputEmpID is a variable that will hold the value input by the user for employee ID. This we will be creating in a while. As the method we are invoking is a GET operation and consumes json data, these properties are being set in lines 5 through 7. Finally, we are sending the request in line 13. In line 15, we use jsonHelper.fromJSON to convert received JSON data to a Java object. The required Java objects' structure is defined in class Employee.java whose structure is provided later. Since the response from our service is a simple response consisting of attributes like employee Id, name, design etc, we will just return this parsed response (line 16) and use it to create DC. As mentioned previously, we would like the user to input the employee ID for which he/she wants to perform search. So, in the same class, define a variable inputEmpID which will hold the value input by the user. Generate accessors for this variable. Lastly, we need to create Employee class. Employee class will define how we want to structure the JSON object received from the service. To design the Employee class, run the services’ method in the browser or via analyzer using path parameter as 1. This will give you the output JSON structure. Ours is a simple service that returns a JSONObject with a set of data. Hence, Employee class will just contain this set of data defined with the proper data types. Create Employee.java in the same project as EmployeeDC.java and write the below code: package application; import oracle.adfmf.java.beans.PropertyChangeListener; import oracle.adfmf.java.beans.PropertyChangeSupport; public class Employee { private String dept; private String desig; private int id; private String name; private int salary; private PropertyChangeSupport propertyChangeSupport = new PropertyChangeSupport(this); public void setDept(String dept) {         String oldDept = this.dept; this.dept = dept; propertyChangeSupport.firePropertyChange("dept", oldDept, dept); } public String getDept() { return dept; } public void setDesig(String desig) { String oldDesig = this.desig; this.desig = desig; propertyChangeSupport.firePropertyChange("desig", oldDesig, desig); } public String getDesig() { return desig; } public void setId(int id) { int oldId = this.id; this.id = id; propertyChangeSupport.firePropertyChange("id", oldId, id); } public int getId() { return id; } public void setName(String name) { String oldName = this.name; this.name = name; propertyChangeSupport.firePropertyChange("name", oldName, name); } public String getName() { return name; } public void setSalary(int salary) { int oldSalary = this.salary; this.salary = salary; propertyChangeSupport.firePropertyChange("salary", oldSalary, salary); } public int getSalary() { return salary; } public void addPropertyChangeListener(PropertyChangeListener l) { propertyChangeSupport.addPropertyChangeListener(l); } public void removePropertyChangeListener(PropertyChangeListener l) { propertyChangeSupport.removePropertyChangeListener(l);     } } Now, let us create a DC out of EmployeeDC.java.  DC as shown below is created. Now, you can design the mobile page as usual and invoke the operation of the service. To design the page, go to ViewController project and locate adfmf-feature.xml. Create a new feature called ‘SearchFeature’ by clicking the plus icon. Go the content tab and add an amx page. Call it SearchPage.amx. Call it SearchPage.amx. Remove primary and secondary buttons as we don’t need them and rename the header. Drag and drop inputEmpID from the DC palette onto Panel Page in the structure pane as input text with label. Next, drop fetchEmpDetails method as an ADF button. For a change, let us display the output in a table component instead of the usual form. However, you will notice that if you drag and drop Employee onto the structure pane, there is no option for ADF Mobile Table. Hence, we will need to create the table on our own. To do this, let us first drop Employee as an ADF Read -Only form. This step is needed to get the required bindings. We will be deleting this form in a while. Now, from the Component palette, search for ‘Table Layout’. Drag and drop this below the command button.  Within the tablelayout, insert ‘Row Layout’ and ‘Cell Format’ components. Final table structure should be as shown below. Here, we have also defined some inline styling to render the UI in a nice manner. <amx:tableLayout id="tl1" borderWidth="2" halign="center" inlineStyle="vertical-align:middle;" width="100%" cellPadding="10"> <amx:rowLayout id="rl1" > <amx:cellFormat id="cf1" width="30%"> <amx:outputText value="#{bindings.dept.hints.label}" id="ot7" inlineStyle="color:rgb(0,148,231);"/> </amx:cellFormat> <amx:cellFormat id="cf2"> <amx:outputText value="#{bindings.dept.inputValue}" id="ot8" /> </amx:cellFormat> </amx:rowLayout> <amx:rowLayout id="rl2"> <amx:cellFormat id="cf3" width="30%"> <amx:outputText value="#{bindings.desig.hints.label}" id="ot9" inlineStyle="color:rgb(0,148,231);"/> </amx:cellFormat> <amx:cellFormat id="cf4" > <amx:outputText value="#{bindings.desig.inputValue}" id="ot10"/> </amx:cellFormat> </amx:rowLayout> <amx:rowLayout id="rl3"> <amx:cellFormat id="cf5" width="30%"> <amx:outputText value="#{bindings.id.hints.label}" id="ot11" inlineStyle="color:rgb(0,148,231);"/> </amx:cellFormat> <amx:cellFormat id="cf6" > <amx:outputText value="#{bindings.id.inputValue}" id="ot12"/> </amx:cellFormat> </amx:rowLayout> <amx:rowLayout id="rl4"> <amx:cellFormat id="cf7" width="30%"> <amx:outputText value="#{bindings.name.hints.label}" id="ot13" inlineStyle="color:rgb(0,148,231);"/> </amx:cellFormat> <amx:cellFormat id="cf8"> <amx:outputText value="#{bindings.name.inputValue}" id="ot14"/> </amx:cellFormat> </amx:rowLayout> <amx:rowLayout id="rl5"> <amx:cellFormat id="cf9" width="30%"> <amx:outputText value="#{bindings.salary.hints.label}" id="ot15" inlineStyle="color:rgb(0,148,231);"/> </amx:cellFormat> <amx:cellFormat id="cf10"> <amx:outputText value="#{bindings.salary.inputValue}" id="ot16"/> </amx:cellFormat> </amx:rowLayout>     </amx:tableLayout> The values used in the output text of the table come from the bindings obtained from the ADF Form created earlier. As we have used the bindings and don’t need the form anymore, let us delete the form.  One last thing before we deploy. When user changes employee ID, we want to clear the table contents. For this we associate a value change listener with the input text box. Click New in the resulting dialog to create a managed bean. Next, we create a method within the managed bean. For this, click on the New button associated with method. Call the method ‘empIDChange’. Open myClass.java and write the below code in empIDChange(). public void empIDChange(ValueChangeEvent valueChangeEvent) { // Add event code here... //Resetting the values to blank values when employee id changes AdfELContext adfELContext = AdfmfJavaUtilities.getAdfELContext(); ValueExpression ve = AdfmfJavaUtilities.getValueExpression("#{bindings.dept.inputValue}", String.class); ve.setValue(adfELContext, ""); ve = AdfmfJavaUtilities.getValueExpression("#{bindings.desig.inputValue}", String.class); ve.setValue(adfELContext, ""); ve = AdfmfJavaUtilities.getValueExpression("#{bindings.id.inputValue}", int.class); ve.setValue(adfELContext, ""); ve = AdfmfJavaUtilities.getValueExpression("#{bindings.name.inputValue}", String.class); ve.setValue(adfELContext, ""); ve = AdfmfJavaUtilities.getValueExpression("#{bindings.salary.inputValue}", int.class); ve.setValue(adfELContext, ""); } That’s it. Deploy the application to android emulator or device. Some snippets from the app.

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  • High Load mysql on Debian server stops every day. Why?

    - by Oleg Abrazhaev
    I have Debian server with 32 gb memory. And there is apache2, memcached and nginx on this server. Memory load always on maximum. Only 500m free. Most memory leak do MySql. Apache only 70 clients configured, other services small memory usage. When mysql use all memory it stops. And nothing works, need mysql reboot. Mysql configured use maximum 24 gb memory. I have hight weight InnoDB bases. (400000 rows, 30 gb). And on server multithread daemon, that makes many inserts in this tables, thats why InnoDB. There is my mysql config. [mysqld] # # * Basic Settings # default-time-zone = "+04:00" user = mysql pid-file = /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp language = /usr/share/mysql/english skip-external-locking default-time-zone='Europe/Moscow' # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. # # * Fine Tuning # #low_priority_updates = 1 concurrent_insert = ALWAYS wait_timeout = 600 interactive_timeout = 600 #normal key_buffer_size = 2024M #key_buffer_size = 1512M #70% hot cache key_cache_division_limit= 70 #16-32 max_allowed_packet = 32M #1-16M thread_stack = 8M #40-50 thread_cache_size = 50 #orderby groupby sort sort_buffer_size = 64M #same myisam_sort_buffer_size = 400M #temp table creates when group_by tmp_table_size = 3000M #tables in memory max_heap_table_size = 3000M #on disk open_files_limit = 10000 table_cache = 10000 join_buffer_size = 5M # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP #myisam_use_mmap = 1 max_connections = 200 thread_concurrency = 8 # # * Query Cache Configuration # #more ignored query_cache_limit = 50M query_cache_size = 210M #on query cache query_cache_type = 1 # # * Logging and Replication # # Both location gets rotated by the cronjob. # Be aware that this log type is a performance killer. #log = /var/log/mysql/mysql.log # # Error logging goes to syslog. This is a Debian improvement :) # # Here you can see queries with especially long duration log_slow_queries = /var/log/mysql/mysql-slow.log long_query_time = 1 log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. #server-id = 1 #log_bin = /var/log/mysql/mysql-bin.log server-id = 1 log-bin = /var/lib/mysql/mysql-bin #replicate-do-db = gate log-bin-index = /var/lib/mysql/mysql-bin.index log-error = /var/lib/mysql/mysql-bin.err relay-log = /var/lib/mysql/relay-bin relay-log-info-file = /var/lib/mysql/relay-bin.info relay-log-index = /var/lib/mysql/relay-bin.index binlog_do_db = 24avia expire_logs_days = 10 max_binlog_size = 100M read_buffer_size = 4024288 innodb_buffer_pool_size = 5000M innodb_flush_log_at_trx_commit = 2 innodb_thread_concurrency = 8 table_definition_cache = 2000 group_concat_max_len = 16M #binlog_do_db = gate #binlog_ignore_db = include_database_name # # * BerkeleyDB # # Using BerkeleyDB is now discouraged as its support will cease in 5.1.12. #skip-bdb # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! # You might want to disable InnoDB to shrink the mysqld process by circa 100MB. #skip-innodb # # * Security Features # # Read the manual, too, if you want chroot! # chroot = /var/lib/mysql/ # # For generating SSL certificates I recommend the OpenSSL GUI "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem [mysqldump] quick quote-names max_allowed_packet = 500M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 32M key_buffer_size = 512M # # * NDB Cluster # # See /usr/share/doc/mysql-server-*/README.Debian for more information. # # The following configuration is read by the NDB Data Nodes (ndbd processes) # not from the NDB Management Nodes (ndb_mgmd processes). # # [MYSQL_CLUSTER] # ndb-connectstring=127.0.0.1 # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/ Please, help me make it stable. Memory used /etc/mysql # free total used free shared buffers cached Mem: 32930800 32766424 164376 0 139208 23829196 -/+ buffers/cache: 8798020 24132780 Swap: 33553328 44660 33508668 Maybe my problem not in memory, but MySQL stops every day. As you can see, cache memory free 24 gb. Thank to Michael Hampton? for correction. Load overage on server 3.5. Maybe hdd or another problem? Maybe my config not optimal for 30gb InnoDB ? I'm already try mysqltuner and tunung-primer.sh , but they marked all green. Mysqltuner output mysqltuner >> MySQLTuner 1.0.1 - Major Hayden <[email protected]> >> Bug reports, feature requests, and downloads at http://mysqltuner.com/ >> Run with '--help' for additional options and output filtering -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.5.24-9-log [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in MyISAM tables: 112G (Tables: 1528) [--] Data in InnoDB tables: 39G (Tables: 340) [--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17) [!!] Total fragmented tables: 344 -------- Performance Metrics ------------------------------------------------- [--] Up for: 8h 18m 33s (14M q [478.333 qps], 259K conn, TX: 9B, RX: 5B) [--] Reads / Writes: 84% / 16% [--] Total buffers: 10.5G global + 81.1M per thread (200 max threads) [OK] Maximum possible memory usage: 26.3G (83% of installed RAM) [OK] Slow queries: 1% (259K/14M) [!!] Highest connection usage: 100% (201/200) [OK] Key buffer size / total MyISAM indexes: 1.5G/5.6G [OK] Key buffer hit rate: 100.0% (6B cached / 1M reads) [OK] Query cache efficiency: 74.3% (8M cached / 11M selects) [OK] Query cache prunes per day: 0 [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 247K sorts) [!!] Joins performed without indexes: 106025 [!!] Temporary tables created on disk: 49% (351K on disk / 715K total) [OK] Thread cache hit rate: 99% (249 created / 259K connections) [!!] Table cache hit rate: 15% (2K open / 13K opened) [OK] Open file limit used: 15% (3K/20K) [OK] Table locks acquired immediately: 99% (4M immediate / 4M locks) [!!] InnoDB data size / buffer pool: 39.4G/5.9G -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance MySQL started within last 24 hours - recommendations may be inaccurate Reduce or eliminate persistent connections to reduce connection usage Adjust your join queries to always utilize indexes Temporary table size is already large - reduce result set size Reduce your SELECT DISTINCT queries without LIMIT clauses Increase table_cache gradually to avoid file descriptor limits Variables to adjust: max_connections (> 200) wait_timeout (< 600) interactive_timeout (< 600) join_buffer_size (> 5.0M, or always use indexes with joins) table_cache (> 10000) innodb_buffer_pool_size (>= 39G) Mysql primer output -- MYSQL PERFORMANCE TUNING PRIMER -- - By: Matthew Montgomery - MySQL Version 5.5.24-9-log x86_64 Uptime = 0 days 8 hrs 20 min 50 sec Avg. qps = 478 Total Questions = 14369568 Threads Connected = 16 Warning: Server has not been running for at least 48hrs. It may not be safe to use these recommendations To find out more information on how each of these runtime variables effects performance visit: http://dev.mysql.com/doc/refman/5.5/en/server-system-variables.html Visit http://www.mysql.com/products/enterprise/advisors.html for info about MySQL's Enterprise Monitoring and Advisory Service SLOW QUERIES The slow query log is enabled. Current long_query_time = 1.000000 sec. You have 260626 out of 14369701 that take longer than 1.000000 sec. to complete Your long_query_time seems to be fine BINARY UPDATE LOG The binary update log is enabled Binlog sync is not enabled, you could loose binlog records during a server crash WORKER THREADS Current thread_cache_size = 50 Current threads_cached = 45 Current threads_per_sec = 0 Historic threads_per_sec = 0 Your thread_cache_size is fine MAX CONNECTIONS Current max_connections = 200 Current threads_connected = 11 Historic max_used_connections = 201 The number of used connections is 100% of the configured maximum. You should raise max_connections INNODB STATUS Current InnoDB index space = 214 M Current InnoDB data space = 39.40 G Current InnoDB buffer pool free = 0 % Current innodb_buffer_pool_size = 5.85 G Depending on how much space your innodb indexes take up it may be safe to increase this value to up to 2 / 3 of total system memory MEMORY USAGE Max Memory Ever Allocated : 23.46 G Configured Max Per-thread Buffers : 15.84 G Configured Max Global Buffers : 7.54 G Configured Max Memory Limit : 23.39 G Physical Memory : 31.40 G Max memory limit seem to be within acceptable norms KEY BUFFER Current MyISAM index space = 5.61 G Current key_buffer_size = 1.47 G Key cache miss rate is 1 : 5578 Key buffer free ratio = 77 % Your key_buffer_size seems to be fine QUERY CACHE Query cache is enabled Current query_cache_size = 200 M Current query_cache_used = 101 M Current query_cache_limit = 50 M Current Query cache Memory fill ratio = 50.59 % Current query_cache_min_res_unit = 4 K MySQL won't cache query results that are larger than query_cache_limit in size SORT OPERATIONS Current sort_buffer_size = 64 M Current read_rnd_buffer_size = 256 K Sort buffer seems to be fine JOINS Current join_buffer_size = 5.00 M You have had 106606 queries where a join could not use an index properly You have had 8 joins without keys that check for key usage after each row join_buffer_size >= 4 M This is not advised You should enable "log-queries-not-using-indexes" Then look for non indexed joins in the slow query log. OPEN FILES LIMIT Current open_files_limit = 20210 files The open_files_limit should typically be set to at least 2x-3x that of table_cache if you have heavy MyISAM usage. Your open_files_limit value seems to be fine TABLE CACHE Current table_open_cache = 10000 tables Current table_definition_cache = 2000 tables You have a total of 1910 tables You have 2151 open tables. The table_cache value seems to be fine TEMP TABLES Current max_heap_table_size = 2.92 G Current tmp_table_size = 2.92 G Of 366426 temp tables, 49% were created on disk Perhaps you should increase your tmp_table_size and/or max_heap_table_size to reduce the number of disk-based temporary tables Note! BLOB and TEXT columns are not allow in memory tables. If you are using these columns raising these values might not impact your ratio of on disk temp tables. TABLE SCANS Current read_buffer_size = 3 M Current table scan ratio = 2846 : 1 read_buffer_size seems to be fine TABLE LOCKING Current Lock Wait ratio = 1 : 185 You may benefit from selective use of InnoDB. If you have long running SELECT's against MyISAM tables and perform frequent updates consider setting 'low_priority_updates=1'

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  • How SQL Server 2014 impacts Red Gate’s SQL Compare

    - by Michelle Taylor
    SQL Compare 10.7 successfully connects to SQL Server 2014, but it doesn’t yet cover the SQL Server 2014 features which would require us to make major changes to SQL Compare to support. In this post I’m going to talk about the SQL Server 2014 features we’ve already begun supporting, and which ones we’re working on for the next release of SQL Compare (v11). From SQL Compare’s perspective, the new memory-optimized table functionality (some might know it as ‘Hekaton’) has been the most important change. It can’t be described as its own object type, but the new functionality is split across two existing object types (three if you count indexes), as it also comes with native stored procedures and inline indexes. Along with connectivity support, the SQL Compare team has already implemented the first part of the puzzle – inline specification of indexes. These are essential for memory-optimized tables because it’s not possible to alter the memory optimized table’s structure, and so indexes can’t be added after the fact without dropping the table. Books Online  shows this in more detail in the table_index and column_index clauses of http://msdn.microsoft.com/en-us/library/ms174979(v=sql.120).aspx. SQL Compare 10.7 currently supports reading the new inline index specification from script folders and source control repositories, and will write out inline indexes where it’s necessary to do so (i.e. in UDDTs or when attempting to write projects compatible with the SSDT database project format). However, memory-optimized tables themselves are not yet supported in 10.7. The team is actively working on making them available in the v11 release with full support later in the year, and in a beta version before that. Fortunately, SQL Compare already has some ways of handling tables that have to be dropped and created rather than altered, which are being adapted to handle this new kind of table. Because it’s one of the largest new database engine features, there’s an equally large Books Online section on memory-optimized tables, but for us the most important parts of the documentation are the normal table features that are changed or unsupported and the new syntax found in the T-SQL reference pages. We are treating SQL Compare’s support of Natively Compiled Stored Procedures as a separate unit of work, which will be available in a subsequent beta and also feed into the v11 release. This new type of stored procedure is designed to work with memory-optimized tables to maintain the performance improvements gained by them – but you can still also access memory-optimized tables from normal stored procedures and ad-hoc queries. To us, they’re essentially a limited-syntax stored procedure with a few extra options in the create statement, embodied in the updated CREATE PROCEDURE documentation and with the detailed limitations. They should be easier to handle than memory-optimized tables simply because the handling of stored procedures is less sensitive to dropping the object than the handling of tables. However, both share an incompatibility with DDL triggers and Event Notifications which mean we’ll need to temporarily disable these during the specific deployment operations that involve them – don’t worry, we’ll supply a warning if this is the case so that you can check your auditing arrangements can handle the situation. There are also a handful of other improvements in SQL Server 2014 which affect SQL Compare and SQL Data Compare that are not connected to memory optimized tables. The largest of these are the improvements to columnstore indexes, with the capability to create clustered columnstore indexes and update columnstore tables through them – for more detail, take a look at the new syntax reference. There’s also a new index option for better compression of columnstores (COLUMNSTORE_ARCHIVE) and a new statistics option for incremental per-partition statistics, plus the 90 compatibility level is being retired. We’re planning to finish up these small clean-up features last, and be ready to release SQL Compare 11 with full SQL 2014 support early in Q3 this year. For a more thorough overview of what’s new in SQL Server 2014, Books Online’s What’s New section is a good place to start (although almost all the changes in this version are in the Database Engine).

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  • SQL SERVER – Fix: Error : 402 The data types ntext and varchar are incompatible in the equal to operator

    - by pinaldave
    Some errors are very simple to understand but the solution of the same is not easy to figure out. Here is one of the similar errors where it clearly suggests where the problem is but does not tell what is the solution. Additionally, there are multiple solutions so developers often get confused with which one is correct and which one is not correct. Let us first recreate scenario and understand where the problem is. Let us run following USE Tempdb GO CREATE TABLE TestTable (ID INT, MyText NTEXT) GO SELECT ID, MyText FROM TestTable WHERE MyText = 'AnyText' GO DROP TABLE TestTable GO When you run above script it will give you following error. Msg 402, Level 16, State 1, Line 1 The data types ntext and varchar are incompatible in the equal to operator. One of the questions I often receive is that voucher is for sure compatible to equal to operator, then why does this error show up. Well, the answer is much simpler I think we have not understood the error message properly. Please see the image below. The next and varchar are not compatible when compared with each other using equal sign. Now let us change the data type on the right side of the string to nvarchar from varchar. To do that we will put N’ before the string. USE Tempdb GO CREATE TABLE TestTable (ID INT, MyText NTEXT) GO SELECT ID, MyText FROM TestTable WHERE MyText = N'AnyText' GO DROP TABLE TestTable GO When you run above script it will give following error. Msg 402, Level 16, State 1, Line 1 The data types ntext and nvarchar are incompatible in the equal to operator. You can see that error message also suggests that now we are comparing next to nvarchar. Now as we have understood the error properly, let us see various solutions to the above problem. Solution 1: Convert the data types to match with each other using CONVERT function. Change the datatype of the MyText to nvarchar. SELECT ID, MyText FROM TestTable WHERE CONVERT(NVARCHAR(MAX), MyText) = N'AnyText' GO Solution 2: Convert the data type of columns from NTEXT to NVARCHAR(MAX) (TEXT to VARCHAR(MAX) ALTER TABLE TestTable ALTER COLUMN MyText NVARCHAR(MAX) GO Now you can run the original query again and it will work fine. Solution 3: Using LIKE command instead of Equal to command. SELECT ID, MyText FROM TestTable WHERE MyText LIKE 'AnyText' GO Well, any of the three of the solutions will work. Here is my suggestion if you can change the column data type from ntext or text to nvarchar or varchar, you should follow that path as text and ntext datatypes are marked as deprecated. All developers any way to change the deprecated data types in future, it will be a good idea to change them right early. If due to any reason you can not convert the original column use Solution 1 for temporary fix. Solution 3 is the not the best solution and use it as a last option. Did I miss any other method? If yes, please let me know and I will add the solution to original blog post with due credit. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Speed up SQL Server queries with PREFETCH

    - by Akshay Deep Lamba
    Problem The SAN data volume has a throughput capacity of 400MB/sec; however my query is still running slow and it is waiting on I/O (PAGEIOLATCH_SH). Windows Performance Monitor shows data volume speed of 4MB/sec. Where is the problem and how can I find the problem? Solution This is another summary of a great article published by R. Meyyappan at www.sqlworkshops.com.  In my opinion, this is the first article that highlights and explains with working examples how PREFETCH determines the performance of a Nested Loop join.  First of all, I just want to recall that Prefetch is a mechanism with which SQL Server can fire up many I/O requests in parallel for a Nested Loop join. When SQL Server executes a Nested Loop join, it may or may not enable Prefetch accordingly to the number of rows in the outer table. If the number of rows in the outer table is greater than 25 then SQL will enable and use Prefetch to speed up query performance, but it will not if it is less than 25 rows. In this section we are going to see different scenarios where prefetch is automatically enabled or disabled. These examples only use two tables RegionalOrder and Orders.  If you want to create the sample tables and sample data, please visit this site www.sqlworkshops.com. The breakdown of the data in the RegionalOrders table is shown below and the Orders table contains about 6 million rows. In this first example, I am creating a stored procedure against two tables and then execute the stored procedure.  Before running the stored proceudre, I am going to include the actual execution plan. --Example provided by www.sqlworkshops.com --Create procedure that pulls orders based on City --Do not forget to include the actual execution plan CREATE PROC RegionalOrdersProc @City CHAR(20) AS BEGIN DECLARE @OrderID INT, @OrderDetails CHAR(200) SELECT @OrderID = o.OrderID, @OrderDetails = o.OrderDetails       FROM RegionalOrders ao INNER JOIN Orders o ON (o.OrderID = ao.OrderID)       WHERE City = @City END GO SET STATISTICS time ON GO --Example provided by www.sqlworkshops.com --Execute the procedure with parameter SmallCity1 EXEC RegionalOrdersProc 'SmallCity1' GO After running the stored procedure, if we right click on the Clustered Index Scan and click Properties we can see the Estimated Numbers of Rows is 24.    If we right click on Nested Loops and click Properties we do not see Prefetch, because it is disabled. This behavior was expected, because the number of rows containing the value ‘SmallCity1’ in the outer table is less than 25.   Now, if I run the same procedure with parameter ‘BigCity’ will Prefetch be enabled? --Example provided by www.sqlworkshops.com --Execute the procedure with parameter BigCity --We are using cached plan EXEC RegionalOrdersProc 'BigCity' GO As we can see from the below screenshot, prefetch is not enabled and the query takes around 7 seconds to execute. This is because the query used the cached plan from ‘SmallCity1’ that had prefetch disabled. Please note that even if we have 999 rows for ‘BigCity’ the Estimated Numbers of Rows is still 24.   Finally, let’s clear the procedure cache to trigger a new optimization and execute the procedure again. DBCC freeproccache GO EXEC RegionalOrdersProc 'BigCity' GO This time, our procedure runs under a second, Prefetch is enabled and the Estimated Number of Rows is 999.   The RegionalOrdersProc can be optimized by using the below example where we are using an optimizer hint. I have also shown some other hints that could be used as well. --Example provided by www.sqlworkshops.com --You can fix the issue by using any of the following --hints --Create procedure that pulls orders based on City DROP PROC RegionalOrdersProc GO CREATE PROC RegionalOrdersProc @City CHAR(20) AS BEGIN DECLARE @OrderID INT, @OrderDetails CHAR(200) SELECT @OrderID = o.OrderID, @OrderDetails = o.OrderDetails       FROM RegionalOrders ao INNER JOIN Orders o ON (o.OrderID = ao.OrderID)       WHERE City = @City       --Hinting optimizer to use SmallCity2 for estimation       OPTION (optimize FOR (@City = 'SmallCity2'))       --Hinting optimizer to estimate for the currnet parameters       --option (recompile)       --Hinting optimize not to use histogram rather       --density for estimation (average of all 3 cities)       --option (optimize for (@City UNKNOWN))       --option (optimize for UNKNOWN) END GO Conclusion, this tip was mainly aimed at illustrating how Prefetch can speed up query execution and how the different number of rows can trigger this.

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  • Stretch in multiple components using af:popup, af:region, af:panelTabbed

    - by Arvinder Singh
    Case study: I have a pop-up(dialogue) that contains a region(separate taskflow) showing a tab. The contents of this tab is in a region having a separate taskflow. The jsff page of this taskflow contains a panelSplitter which in turn contains a table. In short the components are : pop-up(dialogue) --> region(separate taskflow) --> tab --> region(separate taskflow) --> panelSplitter --> table At times the tab is not displayed with 100% width or the table in panelSplitter is not 100% visible or the splitter is not visible. Maintaining the stretch for all the components is difficult......not any more!!! Below is the solution that you can make use of in many similar scenarios. I am mentioning the major code snippets affecting the stretch and alignment. pop-up: <af:popup> <af:dialog id="d2" type="none" title="" inlineStyle="width:1200px"> <af:region value="#{bindings.PriceChangePopupFlow1.regionModel}" id="r1"/> </af:dialog> The above region is a jsff containing multiple tabs. I am showing code for a single tab. I kept the tab in a panelStretchLayout. <af:panelStretchLayout id="psl1" topHeight="300px" styleClass="AFStretchWidth"> <af:panelTabbed id="pt1"> <af:showDetailItem text="PO Details" id="sdi1" stretchChildren="first" > <af:region value="#{bindings.PriceChangePurchaseOrderFlow1.regionModel}" id="r1" binding="# {pageFlowScope.priceChangePopupBean.poDetailsRegion}" /> This "region" displays a .jsff containing a table in a panelSplitter. <af:panelSplitter id="ps1"  orientation="horizontal" splitterPosition="700"> <f:facet name="first"> <af:panelHeader text="PurchaseOrder" id="ph1"> <af:table id="md1" rows="#{bindings.PurchaseOrderVO.rangeSize}" That's it!!! We're done... Note the stretchChildren="first" attribute in the af:showDetailItem. That does the trick for us. Oracle docs say the following about stretchChildren :  Valid Values: none, first The stretching behavior for children. Acceptable values include: "none": does not attempt to stretch any children (the default value and the value you need to use if you have more than a single child; also the value you need to use if the child does not support being stretched) "first": stretches the first child (not to be used if you have multiple children as such usage will produce unreliable results; also not to be used if the child does not support being stretched)

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  • Inappropriate Updates?

    - by Tony Davis
    A recent Simple-talk article by Kathi Kellenberger dissected the fastest SQL solution, submitted by Peter Larsson as part of Phil Factor's SQL Speed Phreak challenge, to the classic "running total" problem. In its analysis of the code, the article re-ignited a heated debate regarding the techniques that should, and should not, be deemed acceptable in your search for fast SQL code. Peter's code for running total calculation uses a variation of a somewhat contentious technique, sometimes referred to as a "quirky update": SET @Subscribers = Subscribers = @Subscribers + PeopleJoined - PeopleLeft This form of the UPDATE statement, @variable = column = expression, is documented and it allows you to set a variable to the value returned by the expression. Microsoft does not guarantee the order in which rows are updated in this technique because, in relational theory, a table doesn’t have a natural order to its rows and the UPDATE statement has no means of specifying the order. Traditionally, in cases where a specific order is requires, such as for running aggregate calculations, programmers who used the technique have relied on the fact that the UPDATE statement, without the WHERE clause, is executed in the order imposed by the clustered index, or in heap order, if there isn’t one. Peter wasn’t satisfied with this, and so used the ingenious device of assuring the order of the UPDATE by the use of an "ordered CTE", based on an underlying temporary staging table (a heap). However, in either case, the ordering is still not guaranteed and, in addition, would be broken under conditions of parallelism, or partitioning. Many argue, with validity, that this reliance on a given order where none can ever be guaranteed is an abuse of basic relational principles, and so is a bad practice; perhaps even irresponsible. More importantly, Microsoft doesn't wish to support the technique and offers no guarantee that it will always work. If you put it into production and it breaks in a later version, you can't file a bug. As such, many believe that the technique should never be tolerated in a production system, under any circumstances. Is this attitude justified? After all, both forms of the technique, using a clustered index to guarantee the order or using an ordered CTE, have been tested rigorously and are proven to be robust; although not guaranteed by Microsoft, the ordering is reliable, provided none of the conditions that are known to break it are violated. In Peter's particular case, the technique is being applied to a temporary table, where the developer has full control of the data ordering, and indexing, and knows that the table will never be subject to parallelism or partitioning. It might be argued that, in such circumstances, the technique is not really "quirky" at all and to ban it from your systems would server no real purpose other than to deprive yourself of a reliable technique that has uses that extend well beyond the running total calculations. Of course, it is doubly important that such a technique, including its unsupported status and the assumptions that underpin its success, is fully and clearly documented, preferably even when posting it online in a competition or forum post. Ultimately, however, this technique has been available to programmers throughout the time Sybase and SQL Server has existed, and so cannot be lightly cast aside, even if one sympathises with Microsoft for the awkwardness of maintaining an archaic way of doing updates. After all, a Table hint could easily be devised that, if specified in the WITH (<Table_Hint_Limited>) clause, could be used to request the database engine to do the update in the conventional order. Then perhaps everyone would be satisfied. Cheers, Tony.

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  • Entity Framework - Single EMDX Mapping Multiple Database

    - by michaelalisonalviar
    Because of my recent craze on Entity Framework thanks to Sir Humprey, I have continuously searched the Internet for tutorials on how to apply it to our current system. So I've come to learn that with EF, I can eliminate the numerous coding of methods/functions for CRUD operations, my overly used assigning of connection strings, Data Adapters or Data Readers as Entity Framework will map my desired database and will do its magic to create entities for each table I want (using EF Powertool) and does all the methods/functions for my Crud Operations. But as I begin applying it to a new project I was assigned to, I realized our current server is designed to contain each similar entities in different databases. For example Our lookup tables are stored in LookupDb, Accounting-related tables are in AccountingDb, Sales-related tables in SalesDb. My dilemma is I have to use an existing table from LookupDB and use it as a look-up for my new table. Then I have found Miss Rachel's Blog (here)Thank You Miss Rachel!  which enables me to let EF think that my TableLookup1 is in the AccountingDB using the following steps. Im on VS 2010, I am using C# , Using Entity Framework 5, SQL Server 2008 as our DB ServerStep 1:Creating A SQL Synonym. If you want a more detailed discussion on synonyms, this was what i have read -> (link here). To simply put it, A synonym enabled me to simplify my query for the Look-up table when I'm using the AccountingDB fromSELECT [columns] FROM LookupDB.dbo.TableLookup1toSELECT [columns] FROM TableLookup1Syntax: CREATE SYNONYM  TableLookup1(1) FOR LookupDB.dbo.TableLookup1 (2)1. What you want to call the table on your other DB2. DataBaseName.schema.TableNameStep 2: We will now follow Miss Rachel's steps. you can either visit the link on the original topic I posted earlier or just follow the step I made.1. I created a Visual Basic Solution that will contain the 4 projects needed to complete the merging2. First project will contain the edmx file pointing to the AccountingDB3. Second project will contain the edmx file pointing to the LookupDB4. Third Project will will be our repository of the merged edmx file. Create an edmx file pointing To AccountingDB as this the database that we created the Synonym on.Reminder: Aside from using the same name for the Entities, please make sure that you have the same Model Namespace for all your Entities  5. Fourth project that will contain the beautiful EDMX merger that Miss Rachel created that will free you from Hard coding of the merge/recoding the Edmx File of the third project everytime a change is done on either one of the first two projects' Edmx File.6. Run the solution, but make sure that on the solutions properties Single startup project is selected and the project containing the EDMX merger is selected.7. After running the solution, double click on the EDMX file of the 3rd project and set Lazy Loading Enabled = False. This will let you use the tables/entities that you see in that EDMX File.8. Feel free to do your CRUD Operations.I don't know if EF 5 already has a feature to support synonyms as I am still a newbie on that aspect but I have seen a linked where there are supposed suggestions on Entity Framework upgrades and one is the "Support for multiple databases"  So that's it! Thanks for reading!

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  • SQL Server Transaction Marks: Restoring multiple databases to a common relative point

    - by Mladen Prajdic
    We’re all familiar with the ability to restore a database to point in time using the RESTORE WITH STOPAT statement. But what if we have multiple databases that are accessed from one application or are modifying each other? And over multiple instances? And all databases have different workloads? And we want to restore all of the databases to some known common relative point? The catch here is that this common relative point isn’t the same point in time for all databases. This common relative point in time might be now in DB1, now-1 hour in DB2 and yesterday in DB3. And we don’t know the exact times. Let me introduce you to Transaction Marks. When we run a marked transaction using the WITH MARK option a flag is set in the transaction log and a row is added to msdb..logmarkhistory table. When restoring a transaction log backup we can restore to either before or after that marked transaction. The best thing is that we don’t even need to have one database modifying another database. All we have to do is use a marked transaction with the same name in different database. Let’s see how this works with an example. The code comments say what’s going on. USE master GOCREATE DATABASE TestTxMark1GOUSE TestTxMark1GOCREATE TABLE TestTable1( ID INT, VALUE UNIQUEIDENTIFIER) -- insert some data into the table so we can have a starting pointINSERT INTO TestTable1SELECT ROW_NUMBER() OVER(ORDER BY number) AS RN, NULLFROM master..spt_valuesORDER BY RNSELECT *FROM TestTable1GO-- TAKE A FULL BACKUP of the databseBACKUP DATABASE TestTxMark1 TO DISK = 'c:\TestTxMark1.bak'GO USE master GOCREATE DATABASE TestTxMark2GOUSE TestTxMark2GOCREATE TABLE TestTable2( ID INT, VALUE UNIQUEIDENTIFIER)-- insert some data into the table so we can have a starting pointINSERT INTO TestTable2SELECT ROW_NUMBER() OVER(ORDER BY number) AS RN, NEWID()FROM master..spt_valuesORDER BY RNSELECT *FROM TestTable2GO-- TAKE A FULL BACKUP of our databseBACKUP DATABASE TestTxMark2 TO DISK = 'c:\TestTxMark2.bak'GO -- start a marked transaction that modifies both databasesBEGIN TRAN TxDb WITH MARK -- update values from NULL to random value UPDATE TestTable1 SET VALUE = NEWID(); -- update first 100 values from random value -- to NULL in different DB UPDATE TestTxMark2.dbo.TestTable2 SET VALUE = NULL WHERE ID <= 100;COMMITGO     -- some time goes by here -- with various database activity... -- We see two entries for marks in each database. -- This is just informational and has no bearing on the restore itself.SELECT * FROM msdb..logmarkhistory USE masterGO-- create a log backup to restore to mark pointBACKUP LOG TestTxMark1 TO DISK = 'c:\TestTxMark1.trn'GO-- drop the database so we can restore it backDROP DATABASE TestTxMark1GO USE masterGO-- create a log backup to restore to mark pointBACKUP LOG TestTxMark2 TO DISK = 'c:\TestTxMark2.trn'GO-- drop the database so we can restore it backDROP DATABASE TestTxMark2GO -- RESTORE THE DATABASE BACK BEFORE OUR TRANSACTION-- restore the full backup RESTORE DATABASE TestTxMark1 FROM DISK = 'c:\TestTxMark1.bak' WITH NORECOVERY;-- restore the log backup to the transaction markRESTORE LOG TestTxMark1 FROM DISK = 'c:\TestTxMark1.trn' WITH RECOVERY, -- recover to state before the transaction STOPBEFOREMARK = 'TxDb'; -- recover to state after the transaction -- STOPATMARK = 'TxDb';GO -- RESTORE THE DATABASE BACK BEFORE OUR TRANSACTION-- restore the full backup RESTORE DATABASE TestTxMark2 FROM DISK = 'c:\TestTxMark2.bak' WITH NORECOVERY;-- restore the log backup to the transaction markRESTORE LOG TestTxMark2 FROM DISK = 'c:\TestTxMark2.trn' WITH RECOVERY, -- recover to state before the transaction STOPBEFOREMARK = 'TxDb'; -- recover to state after the transaction -- STOPATMARK = 'TxDb';GO USE TestTxMark1-- we restored to time before the transaction -- so we have NULL values in our tableSELECT * FROM TestTable1 USE TestTxMark2-- we restored to time before the transaction -- so we DON'T have NULL values in our tableSELECT * FROM TestTable2   Transaction marks can be used like a crude sync mechanism for cross database operations. With them we can mark our databases with a common “restore to” point so we know we have a valid state between all databases to restore to.

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  • Recent improvements in Console Performance

    - by loren.konkus
    Recently, the WebLogic Server development and support organizations have worked with a number of customers to quantify and improve the performance of the Administration Console in large, distributed configurations where there is significant latency in the communications between the administration server and managed servers. These improvements fall into two categories: Constraining the amount of time that the Console stalls waiting for communication Reducing and streamlining the amount of data required for an update A few releases ago, we added support for a configurable domain-wide mbean "Invocation Timeout" value on the Console's configuration: general, advanced section for a domain. The default value for this setting is 0, which means wait indefinitely and was chosen for compatibility with the behavior of previous releases. This configuration setting applies to all mbean communications between the admin server and managed servers, and is the first line of defense against being blocked by a stalled or completely overloaded managed server. Each site should choose an appropriate timeout value for their environment and network latency. In the next release of WebLogic Server, we've added an additional console preference, "Management Operation Timeout", to the Console's shared preference page. This setting further constrains how long certain console pages will wait for slowly responding servers before returning partial results. While not all Console pages support this yet, key pages such as the Servers Configuration and Control table pages and the Deployments Control pages have been updated to support this. For example, if a user requests a Servers Table page and a Management Operation Timeout occurs, the table is displayed with both local configuration and remote runtime information from the responding managed servers and only local configuration information for servers that did not yet respond. This means that a troublesome managed server does not impede your ability to manage your domain using the Console. To support these changes, these Console pages have been re-written to use the Work Management feature of WebLogic Server to interact with each server or deployment concurrently, which further improves the responsiveness of these pages. The basic algorithm for these pages is: For each configuration mbean (ie, Servers) populate rows with configuration attributes from the fast, local mbean server Find a WorkManager For each server, Create a Work instance to obtain runtime mbean attributes for the server Schedule Work instance in the WorkManager Call WorkManager.waitForAll to wait WorkItems to finish, constrained by Management Operation Timeout For each WorkItem, if the runtime information obtained was not complete, add a message indicating which server has incomplete data Display collected data in table In addition to these changes to constrain how long the console waits for communication, a number of other changes have been made to reduce the amount and scope of managed server interactions for key pages. For example, in previous releases the Deployments Control table looked at the status of a deployment on every managed server, even those servers that the deployment was not currently targeted on. (This was done to handle an edge case where a deployment's target configuration was changed while it remained running on previously targeted servers.) We decided supporting that edge case did not warrant the performance impact for all, and instead only look at the status of a deployment on the servers it is targeted to. Comprehensive status continues to be available if a user clicks on the 'status' field for a deployment. Finally, changes have been made to the System Status portlet to reduce its impact on Console page display times. Obtaining health information for this display requires several mbean interactions with managed servers. In previous releases, this mbean interaction occurred with every display, and any delay or impediment in these interactions was reflected in the display time for every page. To reduce this impact, we've made several changes in this portlet: Using Work Management to obtain health concurrently Applying the operation timeout configuration to constrain how long we will wait Caching health information to reduce the cost during rapid navigation from page to page and only obtaining new health information if the previous information is over 30 seconds old. Eliminating heath collection if this portlet is minimized. Together, these Console changes have resulted in significant performance improvements for the customers with large configurations and high latency that we have worked with during their development, and some lesser performance improvements for those with small configurations and very fast networks. These changes will be included in the 11g Rel 1 patch set 2 (10.3.3.0) release of WebLogic Server.

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  • Indexing data from multiple tables with Oracle Text

    - by Roger Ford
    It's well known that Oracle Text indexes perform best when all the data to be indexed is combined into a single index. The query select * from mytable where contains (title, 'dog') 0 or contains (body, 'cat') 0 will tend to perform much worse than select * from mytable where contains (text, 'dog WITHIN title OR cat WITHIN body') 0 For this reason, Oracle Text provides the MULTI_COLUMN_DATASTORE which will combine data from multiple columns into a single index. Effectively, it constructs a "virtual document" at indexing time, which might look something like: <title>the big dog</title> <body>the ginger cat smiles</body> This virtual document can be indexed using either AUTO_SECTION_GROUP, or by explicitly defining sections for title and body, allowing the query as expressed above. Note that we've used a column called "text" - this might have been a dummy column added to the table simply to allow us to create an index on it - or we could created the index on either of the "real" columns - title or body. It should be noted that MULTI_COLUMN_DATASTORE doesn't automatically handle updates to columns used by it - if you create the index on the column text, but specify that columns title and body are to be indexed, you will need to arrange triggers such that the text column is updated whenever title or body are altered. That works fine for single tables. But what if we actually want to combine data from multiple tables? In that case there are two approaches which work well: Create a real table which contains a summary of the information, and create the index on that using the MULTI_COLUMN_DATASTORE. This is simple, and effective, but it does use a lot of disk space as the information to be indexed has to be duplicated. Create our own "virtual" documents using the USER_DATASTORE. The user datastore allows us to specify a PL/SQL procedure which will be used to fetch the data to be indexed, returned in a CLOB, or occasionally in a BLOB or VARCHAR2. This PL/SQL procedure is called once for each row in the table to be indexed, and is passed the ROWID value of the current row being indexed. The actual contents of the procedure is entirely up to the owner, but it is normal to fetch data from one or more columns from database tables. In both cases, we still need to take care of updates - making sure that we have all the triggers necessary to update the indexed column (and, in case 1, the summary table) whenever any of the data to be indexed gets changed. I've written full examples of both these techniques, as SQL scripts to be run in the SQL*Plus tool. You will need to run them as a user who has CTXAPP role and CREATE DIRECTORY privilege. Part of the data to be indexed is a Microsoft Word file called "1.doc". You should create this file in Word, preferably containing the single line of text: "test document". This file can be saved anywhere, but the SQL scripts need to be changed so that the "create or replace directory" command refers to the right location. In the example, I've used C:\doc. multi_table_indexing_1.sql : creates a summary table containing all the data, and uses multi_column_datastore Download link / View in browser multi_table_indexing_2.sql : creates "virtual" documents using a procedure as a user_datastore Download link / View in browser

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  • SQL SERVER – Asynchronous Update and Timestamp – Check if Row Values are Changed Since Last Retrieve

    - by pinaldave
    Here is the question received just this morning. “Pinal, Our application is much different than other application you might have come across. In simple words, I would like to call it Asynchronous Updated Application. We need your quick opinion about one of the situation which we are facing. From business side: We have bidding system (similar to eBay but not exactly) and where multiple parties bid on one item, during the last few minutes of bidding many parties try to bid at the same time with the same price. When they hit submit, we would like to check if the original data which they retrieved is changed or not. If the original data which they have retrieved is the same, we will accept their new proposed price. If original data are changed, they will have to resubmit the data with new price. From technical side: We have a row which we retrieve in our application. Multiple users are retrieving the same row. Some of the users will update the value of the row and submit. However, only the very first user should be allowed to update the row and remaining all the users will have to re-fetch the row and updated it once again. We do not want to lock any record as that will create other problems. Do you have any solution for this kind of situation?” Fantastic Question. I believe there is good chance that we can use timestamp datatype in this kind of application. Before we continue let us see following simple example. USE tempdb GO CREATE TABLE SampleTable (ID INT, Col1 VARCHAR(100), TimeStampCol TIMESTAMP) GO INSERT INTO SampleTable (ID, Col1) VALUES (1, 'FirstVal') GO SELECT ID, Col1, TimeStampCol FROM SampleTable st GO UPDATE SampleTable SET Col1 = 'NextValue' GO SELECT ID, Col1, TimeStampCol FROM SampleTable st GO DROP TABLE SampleTable GO Now let us see the resultset. Here is the simple explanation of the scenario. We created a table with simple column with TIMESTAMP datatype. When we inserted a very first value the timestamp was generated. When we updated any value in that row, the timestamp was updated with the new value. Every single time when we update any value in the row, it will generate new timestamp value. Now let us apply this in an original question’s scenario. In that case multiple users are retrieving the same row. Everybody will have the same now same TimeStamp with them. Before any user update any value they should once again retrieve the timestamp from the table and compare with the timestamp they have with them. If both of the timestamp have the same value – the original row has not been updated and we can safely update the row with the new value. After initial update, now the row will contain a new timestamp. Any subsequent update to the same row should also go to the same process of checking the value of the timestamp they have in their memory. In this case, the timestamp from memory will be different from the timestamp in the row. This indicates that row in the table has changed and new updates should not be allowed. I believe timestamp can be very very useful in this kind of scenario. Is there any better alternative? Please leave a comment with the suggestion and I will post on the blog with due credit. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Detect Unicode Usage in SQL Column

    One optimization you can make to a SQL table that is overly large is to change from nvarchar (or nchar) to varchar (or char).  Doing so will cut the size used by the data in half, from 2 bytes per character (+ 2 bytes of overhead for varchar) to only 1 byte per character.  However, you will lose the ability to store Unicode characters, such as those used by many non-English alphabets.  If the tables are storing user-input, and your application is or might one day be used internationally, its likely that using Unicode for your characters is a good thing.  However, if instead the data is being generated by your application itself or your development team (such as lookup data), and you can be certain that Unicode character sets are not required, then switching such columns to varchar/char can be an easy improvement to make. Avoid Premature Optimization If you are working with a lookup table that has a small number of rows, and is only ever referenced in the application by its numeric ID column, then you wont see any benefit to using varchar vs. nvarchar.  More generally, for small tables, you wont see any significant benefit.  Thus, if you have a general policy in place to use nvarchar/nchar because it offers more flexibility, do not take this post as a recommendation to go against this policy anywhere you can.  You really only want to act on measurable evidence that suggests that using Unicode is resulting in a problem, and that you wont lose anything by switching to varchar/char. Obviously the main reason to make this change is to reduce the amount of space required by each row.  This in turn affects how many rows SQL Server can page through at a time, and can also impact index size and how much disk I/O is required to respond to queries, etc.  If for example you have a table with 100 million records in it and this table has a column of type nchar(5), this column will use 5 * 2 = 10 bytes per row, and with 100M rows that works out to 10 bytes * 100 million = 1000 MBytes or 1GB.  If it turns out that this column only ever stores ASCII characters, then changing it to char(5) would reduce this to 5*1 = 5 bytes per row, and only 500MB.  Of course, if it turns out that it only ever stores the values true and false then you could go further and replace it with a bit data type which uses only 1 byte per row (100MB  total). Detecting Whether Unicode Is In Use So by now you think that you have a problem and that it might be alleviated by switching some columns from nvarchar/nchar to varchar/char but youre not sure whether youre currently using Unicode in these columns.  By definition, you should only be thinking about this for a column that has a lot of rows in it, since the benefits just arent there for a small table, so you cant just eyeball it and look for any non-ASCII characters.  Instead, you need a query.  Its actually very simple: SELECT DISTINCT(CategoryName)FROM CategoriesWHERE CategoryName <> CONVERT(varchar, CategoryName) Summary Gregg Stark for the tip. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Cannot Start Nginx Compiled from Source

    - by Jason Alan Kennedy
    I am trying to compile Nginx from source based on the original compiled Nginx server running on my DigitalOcean server ( Ubuntu-14.04 64x ) but with a few extra modules. I can get everything installed smoothly but I can not get it to start. I am sure the ini is correct because I copied the original source off the current running Nginx server [ Even though I see that Nginx now adds the ini when compiling fron source ]. Below is the [ lengthy process ] that I am performing - add sorry but I wanted to be thorough for those who are in need of the info ]. Because I am a newB to Nginx, I am sure I am missing something or just have it all wrong. If you may look over what I have done and see if you spot anything I need/need to change, I will greatly appreciate it. Thnx! With the original Nginx server still running: I check the current/running Nginx configuration so I can build the new Nginx instance the same but with the added modules: nginx -V # The out-put: configure arguments: --with-cc-opt='-g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-Bsymbolic-functions -Wl,-z,relro' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug --with-pcre-jit --with-ipv6 --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_addition_module --with-http_dav_module --with-http_geoip_module --with-http_gzip_static_module --with-http_image_filter_module --with-http_spdy_module --with-http_sub_module --with-http_xslt_module NOTE: The configure arguments below return errors during 'make' so I removed them. I don't know what they are - could this be related to my issue??? --with-cc-opt='-g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-Bsymbolic-functions -Wl,-z,relro' Moving on: # So I don't have to sudo every line: sudo bash # Check for updates first thing: apt-get update # Install various prerequisites needed to compile Nginx: apt-get install build-essential libgd2-xpm-dev lsb-base zlib1g-dev libpcre3 libpcre3-dev libbz2-dev libxslt1-dev libxml2 libssl-dev libgeoip-dev tar unzip openssl # Create System users [ if it doesn't exist - but I see its there on DigitalOceans' Droplets all-ready ]: adduser --system --no-create-home --disabled-login --disabled-password --group www-data # Download NGINX wget http://nginx.org/download/nginx-1.7.4.tar.gz tar -xvzf nginx-1.7.4.tar.gz # Then Google PageSpeed: wget https://github.com/pagespeed/ngx_pagespeed/archive/release-1.8.31.4-beta.zip unzip release-1.8.31.4-beta.zip # cd into the PageSpeed Directory cd ngx_pagespeed-release-1.8.31.4-beta/ # and add the PSOL files in there: wget https://dl.google.com/dl/page-speed/psol/1.8.31.4.tar.gz tar -xzvf 1.8.31.4.tar.gz # Get back to the root directory: cd # I add the ngx_cache_purge module and will install the Nginx Helper plugin for WP later: wget https://github.com/FRiCKLE/ngx_cache_purge/archive/2.1.zip unzip 2.1.zip # Add the headers-more-nginx-module: wget https://github.com/openresty/headers-more-nginx-module/archive/v0.25.zip unzip v0.25.zip # and the naxsi module for added security: wget https://github.com/nbs-system/naxsi/archive/0.53-2.tar.gz tar -xvzf 0.53-2.tar.gz # cd to the new Nginx directory cd nginx-1.7.4 # Set up the configuration build based on the current running Nginx config args and add my additional modules: ./configure \ --add-module=$HOME/naxsi-0.53-2/naxsi_src \ --prefix=/usr/share/nginx \ --conf-path=/etc/nginx/nginx.conf \ --http-log-path=/var/log/nginx/access.log \ --error-log-path=/var/log/nginx/error.log \ --lock-path=/var/lock/nginx.lock \ --pid-path=/run/nginx.pid \ --http-client-body-temp-path=/var/lib/nginx/body \ --http-fastcgi-temp-path=/var/lib/nginx/fastcgi \ --http-proxy-temp-path=/var/lib/nginx/proxy \ --http-scgi-temp-path=/var/lib/nginx/scgi \ --http-uwsgi-temp-path=/var/lib/nginx/uwsgi \ --user=www-data \ --group=www-data \ --with-debug \ --with-pcre-jit \ --with-ipv6 \ --with-http_ssl_module \ --with-http_stub_status_module \ --with-http_realip_module \ --with-http_addition_module \ --with-http_dav_module \ --with-http_geoip_module \ --with-http_gzip_static_module \ --with-http_image_filter_module \ --with-http_spdy_module \ --with-http_sub_module \ --with-http_xslt_module \ --with-mail \ --with-mail_ssl_module \ --add-module=$HOME/ngx_pagespeed-release-1.8.31.4-beta \ --add-module=$HOME/ngx_cache_purge-2.1 \ --add-module=$HOME/headers-more-nginx-module-0.25 [ENTER] Configuration Summary: Configuration summary + using system PCRE library + using system OpenSSL library + md5: using OpenSSL library + sha1: using OpenSSL library + using system zlib library nginx path prefix: "/usr/share/nginx" nginx binary file: "/usr/share/nginx/sbin/nginx" nginx configuration prefix: "/etc/nginx" nginx configuration file: "/etc/nginx/nginx.conf" nginx pid file: "/run/nginx.pid" nginx error log file: "/var/log/nginx/error.log" nginx http access log file: "/var/log/nginx/access.log" nginx http client request body temporary files: "/var/lib/nginx/body" nginx http proxy temporary files: "/var/lib/nginx/proxy" nginx http fastcgi temporary files: "/var/lib/nginx/fastcgi" nginx http uwsgi temporary files: "/var/lib/nginx/uwsgi" nginx http scgi temporary files: "/var/lib/nginx/scgi" Next step: I cd to root and I check the old Nginx folder locations and double checked the 'make' output to see that they are the same: whereis nginx #Output: nginx: /usr/sbin/nginx /etc/nginx /usr/share/nginx NOTE: Not sure about the '/usr/sbin/nginx' - Possible issue??? Next I copy the old /etc/nginx/nginx.conf, /etc/nginx/sites-available/default, /etc/nginx/sites-enabled/default, /etc/init.d/nginx to a text file locally for safe keeping to use in the new Nginx server. Then stop the running Nginx server: service nginx stop , verify it's stopped: service --status-all and the output is: [ - ] nginx To verify that there are two Nginx directories, I cd to: cd nginx* and the output is an error indicating there are two nginx folders - Cool Beans! :) Now Install the new Nginx server: cd nginx-1.7.4 make install # INSTALL OUTPUT ######################################## make -f objs/Makefile install make[1]: Entering directory `/home/walkingfish/nginx-1.7.4' test -d '/usr/share/nginx' || mkdir -p '/usr/share/nginx' test -d '/usr/share/nginx/sbin' || mkdir -p '/usr/share/nginx/sbin' test ! -f '/usr/share/nginx/sbin/nginx' || mv '/usr/share/nginx/sbin/nginx' '/usr/share/nginx/sbin/nginx.old' cp objs/nginx '/usr/share/nginx/sbin/nginx' test -d '/etc/nginx' || mkdir -p '/etc/nginx' cp conf/koi-win '/etc/nginx' cp conf/koi-utf '/etc/nginx' cp conf/win-utf '/etc/nginx' test -f '/etc/nginx/mime.types' || cp conf/mime.types '/etc/nginx' cp conf/mime.types '/etc/nginx/mime.types.default' test -f '/etc/nginx/fastcgi_params' || cp conf/fastcgi_params '/etc/nginx' cp conf/fastcgi_params '/etc/nginx/fastcgi_params.default' test -f '/etc/nginx/fastcgi.conf' || cp conf/fastcgi.conf '/etc/nginx' cp conf/fastcgi.conf '/etc/nginx/fastcgi.conf.default' test -f '/etc/nginx/uwsgi_params' || cp conf/uwsgi_params '/etc/nginx' cp conf/uwsgi_params '/etc/nginx/uwsgi_params.default' test -f '/etc/nginx/scgi_params' || cp conf/scgi_params '/etc/nginx' cp conf/scgi_params '/etc/nginx/scgi_params.default' test -f '/etc/nginx/nginx.conf' || cp conf/nginx.conf '/etc/nginx/nginx.conf' cp conf/nginx.conf '/etc/nginx/nginx.conf.default' test -d '/run' || mkdir -p '/run' test -d '/var/log/nginx' || mkdir -p '/var/log/nginx' test -d '/usr/share/nginx/html' || cp -R html '/usr/share/nginx' test -d '/var/log/nginx' || mkdir -p '/var/log/nginx' ######################################################### I copy/create the files that I saved earlier to txt files in sites-available, the config, default and ini files then symlink them to sites-enabled, and so on. And now to start the server: service nginx start And this is where s#!+ hits the fan - Nada. I check to see if Nginx is running with service --status-all and its not. Also with nginx -V and its not installed??? I reboot the system too and still nothing. So I am not sure what is wrong here. The ini was copied over from the old server along with all the other config files after deleting the old files. When I opened the new compiled files, the nginx default data was present so I replaced them with my old original data prior to starting the new server for the first time. Also to be safe, I rm /etc/nginx/sites-enabled/default and symlinked with ln -s /etc/nginx/sites-available/default /etc/nginx/sites-enabled/default with no errors and I verified that the data was in the sites-enabled/default file. I don't think the server really/fully installed because of the nginx -V result: The program 'nginx' can be found in the following packages: * nginx-core * nginx-extras * nginx-full * nginx-light * nginx-naxsi Try: apt-get install <selected package> Do/should I apt-get install nginx-1.7.4 ?? Or what package do I use being that its a custom package and make install earlier did nothing?? If you need to see the conf files I copied over from the old to the custom server, LMK and I'll post them. Again your help here would be appreciated!

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  • --log-slave-updates is OFF but some updates are still logged to the slave binary log?

    - by quanta
    MySQL version 5.5.14 According to the document, by the default, slave does not log to its binary log any updates that are received from a master server. Here are my config. on the slave: # egrep 'bin|slave' /etc/my.cnf relay-log=mysqld-relay-bin log-bin = /var/log/mysql/mysql-bin binlog-format=MIXED sync_binlog = 1 log-bin-trust-function-creators = 1 mysql> show global variables like 'log_slave%'; +-------------------+-------+ | Variable_name | Value | +-------------------+-------+ | log_slave_updates | OFF | +-------------------+-------+ 1 row in set (0.01 sec) mysql> select @@log_slave_updates; +---------------------+ | @@log_slave_updates | +---------------------+ | 0 | +---------------------+ 1 row in set (0.00 sec) but slave still logs the some changes to its binary logs, let's see the file size: -rw-rw---- 1 mysql mysql 37M Apr 1 01:00 /var/log/mysql/mysql-bin.001256 -rw-rw---- 1 mysql mysql 25M Apr 2 01:00 /var/log/mysql/mysql-bin.001257 -rw-rw---- 1 mysql mysql 46M Apr 3 01:00 /var/log/mysql/mysql-bin.001258 -rw-rw---- 1 mysql mysql 115M Apr 4 01:00 /var/log/mysql/mysql-bin.001259 -rw-rw---- 1 mysql mysql 105M Apr 4 18:54 /var/log/mysql/mysql-bin.001260 and the sample query when reading these binary files with mysqlbinlog utility: #120404 19:08:57 server id 3 end_log_pos 110324763 Query thread_id=382435 exec_time=0 error_code=0 SET TIMESTAMP=1333541337/*!*/; INSERT INTO norep_SplitValues VALUES ( NAME_CONST('cur_string',_utf8'118212' COLLATE 'utf8_general_ci')) /*!*/; # at 110324763 Did I miss something? Reply to @RolandoMySQLDBA: If replication brought this over, then the same query has to be in the relay logs. Please go find the relay log that has the INSERT query with the same TIMESTAMP (1333541337). There is no such query with the same TIMESTAMP in the relay logs. If you cannot find it in the relay logs, then look and see if Infobright is posting the INSERT query. In that instance, the INSERT should be recorded in the binary logs of the Slave. Looking more deeply into the binary logs, I see that almost of the queries are CREATE/INSERT/UPDATE/DROP "temporary" tables, something like this: # at 123873315 #120405 0:42:04 server id 3 end_log_pos 123873618 Query thread_id=395373 exec_time=0 error_code=0 SET TIMESTAMP=1333561324/*!*/; SET @@session.pseudo_thread_id=395373/*!*/; CREATE TEMPORARY TABLE `norep_tmpcampaign` ( `campaignid` INTEGER(11) NOT NULL DEFAULT '0' , `status` INTEGER(11) NOT NULL DEFAULT '0' , `updated` DATETIME, KEY `campaignid` (`campaignid`) )ENGINE=MEMORY /*!*/; # at 123873618 #120405 0:42:04 server id 3 end_log_pos 123873755 Query thread_id=395373 exec_time=0 error_code=0 SET TIMESTAMP=1333561324/*!*/; DROP TABLE IF EXISTS `norep_tmpcampaign1` /* generated by server */ "temporary" here means that they are dropped after calculation is done. I also tells the slave not to replicate any statement matches the norep_ wildcard pattern: replicate-wild-ignore-table=%.norep_% But there is an exception table in the binary logs: # at 123828094 #120405 0:37:21 server id 3 end_log_pos 123828495 Query thread_id=395209 exec_time=0 error_code=0 SET TIMESTAMP=1333561041/*!*/; INSERT INTO sessions (SessionId, ApplicationName, Created, Expires, LockDate, LockId, Timeout, Locked, SessionItems, Fla gs) Values('pgv2exo4y4vo4ccz44vwznu0', '/', '2012-04-05 00:37:21', '2012-04-05 00:57:21', '2012-04-05 00:37:21', 0, 20, 0, 'AwAAAP////8IdXNlcm5hbWUGdXNlcmlkCHBlcm1pdGlkAgAAAAQAAAAGAAAAAQABAAEA', 0) /*!*/; Description: mysql> desc reportingdb.sessions; +-----------------+------------------+------+-----+---------------------+-------+ | Field | Type | Null | Key | Default | Extra | +-----------------+------------------+------+-----+---------------------+-------+ | SessionId | varchar(64) | NO | PRI | | | | ApplicationName | varchar(255) | NO | | | | | Created | timestamp | NO | | 0000-00-00 00:00:00 | | | Expires | timestamp | NO | | 0000-00-00 00:00:00 | | | LockDate | timestamp | NO | | 0000-00-00 00:00:00 | | | LockId | int(11) unsigned | NO | | NULL | | | Timeout | int(11) unsigned | NO | | NULL | | | Locked | bit(1) | NO | | NULL | | | SessionItems | varchar(255) | YES | | NULL | | | Flags | int(11) | NO | | NULL | | +-----------------+------------------+------+-----+---------------------+-------+ I'm sure all these queries are posting by MySQL, not Infobright: $ mysql-ib -u root -p Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 48971 Server version: 5.1.40 build number (revision)=IB_4.0.5_r15240_15370(ice) (static) Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> select * from information_schema.tables where table_name='sessions'; Empty set (0.02 sec) I've been trying some INSERT/UPDATE queries with testing tables on the master, it is copied to the relay logs, not binary logs on slave: # at 311664029 #120405 0:15:23 server id 1 end_log_pos 311664006 Query thread_id=10458250 exec_time=0 error_code=0 use testuser/*!*/; SET TIMESTAMP=1333559723/*!*/; update users set email2='[email protected]' where id=22 /*!*/; Pay attention to the server id, in the relay logs, server id is master's (1) and in the binary log, server id is slave's (3 in this case). Reply to @RolandoMySQLDBA: Thu Apr 5 10:06:00 ICT 2012 Run CREATE DATABASE quantatest; on the Master now, please. Tell me if CREATE DATABASE quantatest; showed up in the Slave's Binary Logs. As I said above: I've been trying some INSERT/UPDATE queries with testing tables on the master, it is copied to the relay logs, not binary logs and you can guess, IO thread copied it to the relay logs, not binary logs. #120405 10:07:25 server id 1 end_log_pos 347573819 Query thread_id=10480775 exec_time=0 error_code=0 SET TIMESTAMP=1333595245/*!*/; /*!\C latin1 *//*!*/; SET @@session.character_set_client=8,@@session.collation_connection=8,@@session.collation_server=8/*!*/; create database quantatest /*!*/; The question must probably change to: why some update queries still logged to the slave binary logs althrough --log-slave-updates is disabled? Where they come from? Here are few last: /*!*/; # at 27492197 #120405 10:12:45 server id 3 end_log_pos 27492370 Query thread_id=410353 exec_time=0 error_code=0 SET TIMESTAMP=1333595565/*!*/; CREATE TEMPORARY TABLE norep_SplitValues ( value VARCHAR(1000) NOT NULL ) ENGINE=MEMORY /*!*/; # at 27492370 #120405 10:12:45 server id 3 end_log_pos 27492445 Query thread_id=410353 exec_time=0 error_code=0 SET TIMESTAMP=1333595565/*!*/; BEGIN /*!*/; # at 27492445 #120405 10:12:45 server id 3 end_log_pos 27492619 Query thread_id=410353 exec_time=0 error_code=0 SET TIMESTAMP=1333595565/*!*/; INSERT INTO norep_SplitValues VALUES ( NAME_CONST('cur_string',_utf8'119577' COLLATE 'utf8_general_ci')) /*!*/; # at 27492619 #120405 10:12:45 server id 3 end_log_pos 27492695 Query thread_id=410353 exec_time=0 error_code=0 SET TIMESTAMP=1333595565/*!*/; COMMIT /*!*/; # at 27492918 #120405 10:12:46 server id 3 end_log_pos 27493115 Query thread_id=410353 exec_time=0 error_code=0 SET TIMESTAMP=1333595566/*!*/; SELECT `reportingdb`.`selfserving_get_locationad`(_utf8'3' COLLATE 'utf8_general_ci',_utf8'' COLLATE 'utf8_general_ci') /*!*/; # at 27493199 #120405 10:12:46 server id 3 end_log_pos 27493353 Query thread_id=410353 exec_time=0 error_code=0 SET TIMESTAMP=1333595566/*!*/; /*!\C utf8 *//*!*/; SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=8/*!*/; DROP TEMPORARY TABLE IF EXISTS `norep_SplitValues` /* generated by server */ /*!*/;

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