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  • VB dataset issue

    - by Gabriel
    Hi. The idea was to create a message box that stores my user name, message, and post datetime into the database as messages are sent. Soon came to realise, what if the user changed his name? So I decided to use the user id (icn) to identify the message poster instead. However, my chunk of codes keep giving me the same error. Says that there are no rows in the dataset ds2. I've tried my Query on my SQL and it works perfectly so I really really need help to spot the error in my chunk of codes here. Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim name As String Dim icn As String Dim message As String Dim time As String Dim tags As String = "" Dim strConn As System.Configuration.ConnectionStringSettings strConn = ConfigurationManager.ConnectionStrings("ufadb") Dim conn As SqlConnection = New SqlConnection(strConn.ToString()) Dim cmd As New SqlCommand("Select * From Message", conn) Dim daMessages As SqlDataAdapter = New SqlDataAdapter(cmd) Dim ds As New DataSet cmd.Connection.Open() daMessages.Fill(ds, "Messages") cmd.Connection.Close() If ds.Tables("Messages").Rows.Count > 0 Then Dim n As Integer = ds.Tables("Messages").Rows.Count Dim i As Integer For i = 0 To n - 1 icn = ds.Tables("Messages").Rows(i).Item("icn") Dim cmd2 As New SqlCommand("SELECT name FROM Member inner join Message ON Member.icn = Message.icn WHERE message.icn = @icn", conn) cmd2.Parameters.AddWithValue("@icn", icn) Dim daName As SqlDataAdapter = New SqlDataAdapter(cmd2) Dim ds2 As New DataSet cmd2.Connection.Open() daName.Fill(ds2, "PosterName") cmd2.Connection.Close() name = ds2.Tables("PosterName").Rows(0).Item("name") message = ds.Tables("Messages").Rows(i).Item("message") time = ds.Tables("Messages").Rows(i).Item("timePosted") tags = time + vbCrLf + name + ": " + vbCrLf + message + vbCrLf + tags Next txtBoard.Text = tags Else txtBoard.Text = "nothing to display" End If End Sub Help will be very much appreciated as I have been on this simple problem for 2 days.

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  • DO NOT BOTHER. THE PROBLEM IS NOT TRANSACTIONS. DUNNO HOW TO CLOSE / DELETE

    - by matti
    THE PROBLEM IS SOLVED. I DUNNO HOW TO CLOSE THIS QUESTION. ANOTHER SERVICE IS PROPABLY RUNNING AT ALMOST SAME SYNC THAT DOES THE THING. MY WORK "MATE" WILL HEAR A THING OR TWO IN THE MORNING. I have following code in windows service: data is in the dataset and it has been populated earlier and then rows are updated and inserted to dataset tables before calling code below. using (dataSetTxn = _cnctn.BeginTransaction()) { try { _somePlanAdptr.UpdateCommand.Transaction = dataSetTxn; _someLogAdptr.InsertCommand.Transaction = dataSetTxn; _someLinkAdptr.InsertCommand.Transaction = dataSetTxn; _someDataAdptr.InsertCommand.Transaction = dataSetTxn; _log.WriteDebug("Updating SomePlanAction"); _somePlanAdptr.Update(_ofDataSet, "SomePlanAction"); _log.WriteDebug(string.Format("Inserting {0} rows to SomeLog")); //error _someLogAdptr.Update(_ofDataSet, "SomeLog"); _log.WriteDebug(string.Format("Updating SomeLink with {0} rows", _ofDataSet.Tables["SomeLink"].Rows.Count)); _someLinkAdptr.Update(_ofDataSet, "SomeLink"); _log.WriteDebug(string.Format("Updating SomeData with {0} rows", _ofDataSet.Tables["SomeData"].Rows.Count)); _someDataAdptr.Update(_ofDataSet, "SomeData"); _log.WriteDebug("Commiting all changes to database."); dataSetTxn.Commit(); } catch (Exception e) { _log.WriteError("Updating database failed -> rollback", e); if (dataSetTxn != null && _cnctn.State == ConnectionState.Open) dataSetTxn.Rollback(); throw e; } } so one of the lines causes an exception log.WriteDebug(string.Format("Inserting {0} rows to SomeLog")); //error still the first adapter's data is updated to database. when debugged the data is not yet updated until the method that calls all (including this bit) exits. The method that does all is timed with System.Threading.Timer. Thanks & BR -Matti

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  • Rails nested attributes with a join model, where one of the models being joined is a new record

    - by gzuki
    I'm trying to build a grid, in rails, for entering data. It has rows and columns, and rows and columns are joined by cells. In my view, I need for the grid to be able to handle having 'new' rows and columns on the edge, so that if you type in them and then submit, they are automatically generated, and their shared cells are connected to them correctly. I want to be able to do this without JS. Rails nested attributes fail to handle being mapped to both a new record and a new column, they can only do one or the other. The reason is that they are a nested specifically in one of the two models, and whichever one they aren't nested in will have no id (since it doesn't exist yet), and when pushed through accepts_nested_attributes_for on the top level Grid model, they will only be bound to the new object created for whatever they were nested in. How can I handle this? Do I have to override rails handling of nested attributes? My models look like this, btw: class Grid < ActiveRecord::Base has_many :rows has_many :columns has_many :cells, :through => :rows accepts_nested_attributes_for :rows, :allow_destroy => true, :reject_if => lambda {|a| a[:description].blank? } accepts_nested_attributes_for :columns, :allow_destroy => true, :reject_if => lambda {|a| a[:description].blank? } end class Column < ActiveRecord::Base belongs_to :grid has_many :cells, :dependent => :destroy has_many :rows, :through => :grid end class Row < ActiveRecord::Base belongs_to :grid has_many :cells, :dependent => :destroy has_many :columns, :through => :grid accepts_nested_attributes_for :cells end class Cell < ActiveRecord::Base belongs_to :row belongs_to :column has_one :grid, :through => :row end

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  • trying to redirect the php page is get id is empty ir does not exists.

    - by user570782
    <? include..... if ($picid != $_GET['picid']) || (empty($picid)) { echo "page not working"; } else { $picid = $_GET['picid']; $query = mysql_query("SELECT * FROM pic_info WHERE picid = 'picid1' ");// problem while($rows = mysql_fetch_assoc($query)): $picid = $rows['picid']; $title = $rows['title']; $link = $rows['link']; $description = $rows['description']; $movie_pic = $rows['movie_pic']; $source = $rows['source']; } $get_comment = mysql_query("SELECT * FROM comment WHERE picid ='$picid'");// work partially $comment_count = mysql_num_rows($get_comment); if ($comment_count>0) { messages = " "; while ($com = mysql_fetch_array($get_comment)){ $comment_id = $com['comment_id']; $name = $com['name']; $message = $com['message']; $time_post= $com['time_post']; $messages .= '<em> on ' .$time_post.'</em><b> '.$name.' said.....</b><br/> '.$message.'<hr/>'; // line with problem } } ?> i am stuck i am trying to say that if $_GET['picid']; is empty echo out error message or if the movid does not exist in the db echo out error message. when i run it i get an error. not sure if i am calling the correct function. what am i doing wrong please help

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  • SQL -- How is DISTINCT so fast without an index?

    - by Jonathan
    Hi, I have a database with a table called 'links' with 600 million rows in it in SQLite. There are 2 columns in the database - a "src" column and a "dest" column. At present there are no indices. There are a fair number of common values between src and dest, but also a fair number of duplicated rows. The first thing I'm trying to do is remove all the duplicate rows, and then perform some additional processing on the results, however I've been encountering some weird issues. Firstly, SELECT * FROM links WHERE src=434923 AND dest=5010182. Now this returns one result fairly quickly and then takes quite a long time to run as I assume it's performing a tablescan on the rest of the 600m rows. However, if I do SELECT DISTINCT * FROM links, then it immediately starts returning rows really quickly. The question is: how is this possible?? Surely for each row, the row must be compared against all of the other rows in the table, but this would require a tablescan of the remaining rows in the table which SHOULD takes ages! Any ideas why SELECT DISTINCT is so much quicker than a standard SELECT?

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  • Python performance: iteration and operations on nested lists

    - by J.J.
    Problem Hey folks. I'm looking for some advice on python performance. Some background on my problem: Given: A mesh of nodes of size (x,y) each with a value (0...255) starting at 0 A list of N input coordinates each at a specified location within the range (0...x, 0...y) Increment the value of the node at the input coordinate and the node's neighbors within range Z up to a maximum of 255. Neighbors beyond the mesh edge are ignored. (No wrapping) BASE CASE: A mesh of size 1024x1024 nodes, with 400 input coordinates and a range Z of 75 nodes. Processing should be O(x*y*Z*N). I expect x, y and Z to remain roughly around the values in the base case, but the number of input coordinates N could increase up to 100,000. My goal is to minimize processing time. Current results I have 2 current implementations: f1, f2 Running speed on my 2.26 GHz Intel Core 2 Duo with Python 2.6.1: f1: 2.9s f2: 1.8s f1 is the initial naive implementation: three nested for loops. f2 is replaces the inner for loop with a list comprehension. Code is included below for your perusal. Question How can I further reduce the processing time? I'd prefer sub-1.0s for the test parameters. Please, keep the recommendations to native Python. I know I can move to a third-party package such as numpy, but I'm trying to avoid any third party packages. Also, I've generated random input coordinates, and simplified the definition of the node value updates to keep our discussion simple. The specifics have to change slightly and are outside the scope of my question. thanks much! f1 is the initial naive implementation: three nested for loops. 2.9s def f1(x,y,n,z): rows = [] for i in range(x): rows.append([0 for i in xrange(y)]) for i in range(n): inputX, inputY = (int(x*random.random()), int(y*random.random())) topleft = (inputX - z, inputY - z) for i in xrange(max(0, topleft[0]), min(topleft[0]+(z*2), x)): for j in xrange(max(0, topleft[1]), min(topleft[1]+(z*2), y)): if rows[i][j] <= 255: rows[i][j] += 1 f2 is replaces the inner for loop with a list comprehension. 1.8s def f2(x,y,n,z): rows = [] for i in range(x): rows.append([0 for i in xrange(y)]) for i in range(n): inputX, inputY = (int(x*random.random()), int(y*random.random())) topleft = (inputX - z, inputY - z) for i in xrange(max(0, topleft[0]), min(topleft[0]+(z*2), x)): l = max(0, topleft[1]) r = min(topleft[1]+(z*2), y) rows[i][l:r] = [j+1 for j in rows[i][l:r] if j < 255]

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  • webservice method is not accessible from jquery ajax

    - by Abhisheks.net
    Hello everyone.. i am using jqery ajax to calling a web service method but is is not doing and genrating error.. the code is here for jquery ajax in asp page var indexNo = 13; //pass the value $(document).ready(function() { $("#a1").click(function() { $.ajax({ type: "POST", url: "myWebService.asmx/GetNewDownline", data: "{'indexNo':user_id}", contentType: "application/json; charset=utf-8", dataType: "json", success: function(msg) { $("#divResult").text(msg.d); } }); }); }); and this is the is web service method using System; using System.Collections; using System.Linq; using System.Web; using System.Web.Services; using System.Web.Services.Protocols; using System.Xml.Linq; using System.Data; using System.Web.Script.Serialization; using TC.MLM.DAL; using TC.MLM.BLL.AS; /// /// Summary description for myWebService /// [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. [System.Web.Script.Services.ScriptService] public class myWebService : System.Web.Services.WebService { public myWebService() { //Uncomment the following line if using designed components //InitializeComponent(); } [WebMethod] public string HelloWorld() { return "Hello World"; } [WebMethod] public string GetNewDownline(string indexNo) { IndexDetails indexDtls = new IndexDetails(); indexDtls.IndexNo = "13"; DataSet ds = new DataSet(); ds = TC.MLM.BLL.AS.Index.getIndexDownLineByIndex(indexDtls); indexNoDownline[] newDownline = new indexNoDownline[ds.Tables[0].Rows.Count]; for (int count = 0; count <= ds.Tables[0].Rows.Count - 1; count++) { newDownline[count] = new indexNoDownline(); newDownline[count].adjustedid = ds.Tables[0].Rows[count]["AdjustedID"].ToString(); newDownline[count].name = ds.Tables[0].Rows[count]["name"].ToString(); newDownline[count].structPostion = ds.Tables[0].Rows[count]["Struct_Position"].ToString(); newDownline[count].indexNo = ds.Tables[0].Rows[count]["IndexNo"].ToString(); newDownline[count].promoterId = ds.Tables[0].Rows[count]["PromotorID"].ToString(); newDownline[count].formNo = ds.Tables[0].Rows[count]["FormNo"].ToString(); } JavaScriptSerializer serializer = new JavaScriptSerializer(); JavaScriptSerializer js = new JavaScriptSerializer(); string resultedDownLine = js.Serialize(newDownline); return resultedDownLine; } public class indexNoDownline { public string adjustedid; public string name; public string indexNo; public string structPostion; public string promoterId; public string formNo; } } please help me something.

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  • How to change the divider height of listview dynamically?

    - by sunil
    Hi, I have a listview in which there should be different divider height between different rows. So, how can we set the divider height dynamically? Suppose, I have 10 rows and there should be a divider height of 5 between first 2 rows and then there should be a divider height of 1 between next 5 rows and so on. Can someone let me know the way of doing this? Regards Sunil

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  • Matrix Transpose TSQL

    - by rmdussa
    Can we do matrix transpose (rows become columns and columns become rows) in standard SQL? 1 2 3 4 5 4 5 6 6 7 7 8 9 8 9 1 3 4 5 6 2 4 5 6 7 changes to 1 4 7 1 2 2 5 8 3 4 3 6 9 5 6 4 6 8 5 6 5 7 9 6 7 how about no of rows < no of column ? let's consider the no of rows it's fixed.

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  • How to increment counters based on a printed array

    - by Sam Liew
    I managed to developed a simple board of 5x5 using random numbers and array. Big achievement for someone like me! :) Now I have to increment the counters depending on the frequency of the numbers. If the value within 0-49 is printed..then nCounter++ If the value within 50-75 is printed..then pCounter++ something like that. The problem is that I don't know how to increase the counters based on the printed board. Here is the code: #include <stdio.h> #include <stdlib.h> #include <time.h> int main() { //Initialize Variables int randomNumber; int rows; int columns; int hdCounter =0; int hCounter = 0; int cCounter = 0; int pCounter = 0; int nCounter = 0; //Declare board size int board[5][5]; //size of board is 5 x 5 //Create the random number generator seed srand(time(NULL)); //Assign the random numbers from 1 - 25 into variable randomNumber //Create the rows for the board for ( rows = 1; rows <= 5 ; rows++ ) { //Create the colimns for the board for ( columns = 1; columns <= 5 ; columns++ ) { //Assign variable randomNumber into variable board randomNumber = rand() %100 + 1; board[rows][columns] = randomNumber; //print the board printf("%d\t", board[rows][columns]); //calculate the frequency of numbers on the printed board if (randomNumber >= 85 && randomNumber <= 100 ) hdCounter++; else if ( randomNumber >= 75 ) hCounter++; else if ( randomNumber >= 65 ) cCounter++; else if ( randomNumber >= 50 ) pCounter++; else if ( randomNumber >= 1 ) nCounter++; else continue; } //Newline after the end of 5th column. printf("\n\n"); } printf( "N \t P \t C \t H \t HD\n\n" ); printf("%d \t %d \t %d \t %d \t %d \t", nCounter, pCounter, cCounter, hCounter, hdCounter); }//end main I tried replacing randomNumber in the if-statement with board[rows][columns] but I seem to get the same undesired results.

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  • Is there a problem when I call SqlAdapter.Update and at the same time call SqlDataReader.Read

    - by Ahmed Said
    I have two applications, one updates a single table which has constant number of rows (128 rows) using SqlDataAdapter.Update method , and another application that select from this table periodically using SqlDataReader. sometimes the DataReader returns only 127 rows not 128, and the update application does not remove or even insert any new rows, it just update. I am asking what is the cause of this behaviour?

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  • Row insertion order entity framework

    - by Wouter
    I'm using a transaction to insert multiple rows in multiple tables. For these rows I would like to add these rows in order. Upon calling SaveChanges all the rows are inserted out of order. When not using a transaction and saving changes after each insertion does keep order, but I really need a transaction for all entries.

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  • When running UPDATE ... datetime = NOW(); will all rows updated have the same date/time?

    - by Darryl Hein
    When you run something similar to: UPDATE table SET datetime = NOW(); on a table with 1 000 000 000 records and the query takes 10 seconds to run, will all the rows have the exact same time (minutes and seconds) or will they have different times? In other words, will the time be when the query started or when each row is updated? I'm running MySQL, but I'm thinking this applies to all dbs.

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  • How to delete child table records during the update of parent table using Hibernate

    - by Harsha
    I have a Parent Table A and child tables B,C with many to one relations. Lets say I have data like, for primary key 1 in parent table A I have 3 rows in child table B and 4 rows in child table C. Now if I want to delete the rows of the child table during an update of the parent table(that means Now, I want to update the table only with one row in each child tables and delete the other rows in them) then how to handle this scenario in hibernate?

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  • continuously fetch data from database using JAVA

    - by deathcaller
    Hi all, I've a scenario where my java program has to continuously communicate with the database table, example my java program has to get the data of my table when new rows are added to it at runtime. There should be continuous communication between my program and database. if the table has 10 rows initially and 2 rows are added by the user, it must detect this and return the rows. My program shouldn't use AJAX and timers. Please Help.

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  • I need a row Added event for a DataGridView

    - by tizzyfoe
    What i want to do is set the background of a row based on some criteria, but the datagrid will be fairly large so i don't want to have to loop over all the rows again. The rows get created me doing something like "myDataGridView.DataSource = MyDataSource, so the only way i can think to edit rows is by using an event. there is a row*s* added event, but that gives me a list of rows that i'd have to iterate over. Thanks in advance for any help.

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  • Create excel files with GemBox.Spreadsheet .NET component

    - by hajan
    Generating excel files from .NET code is not always a very easy task, especially if you need to make some formatting or you want to do something very specific that requires extra coding. I’ve recently tried the GemBox Spreadsheet and I would like to share my experience with you. First of all, you can install GemBox Spreadsheet library from VS.NET 2010 Extension manager by searching in the gallery: Go in the Online Gallery tab (as in the picture bellow) and write GemBox in the Search box on top-right of the Extension Manager, so you will get the following result: Click Download on GemBox.Spreadsheet and you will be directed to product website. Click on the marked link then you will get to the following page where you have the component download link Once you download it, install the MSI file. Open the installation folder and find the Bin folder. There you have GemBox.Spreadsheet.dll in three folders each for different .NET Framework version. Now, lets move to Visual Studio.NET. 1. Create sample ASP.NET Web Application and give it a name. 2. Reference The GemBox.Spreadsheet.dll file in your project So you don’t need to search for the dll file in your disk but you can simply find it in the .NET tab in ‘Add Reference’ window and you have all three versions. I chose the version for 4.0.30319 runtime. Next, I will retrieve data from my Pubs database. I’m using Entity Framework. Here is the code (read the comments in it):             //get data from pubs database, tables: authors, titleauthor, titles             pubsEntities context = new pubsEntities();             var authorTitles = (from a in context.authors                                join tl in context.titleauthor on a.au_id equals tl.au_id                                join t in context.titles on tl.title_id equals t.title_id                                select new AuthorTitles                                {                                     Name = a.au_fname,                                     Surname = a.au_lname,                                     Title = t.title,                                     Price = t.price,                                     PubDate = t.pubdate                                }).ToList();             //using GemBox library now             ExcelFile myExcelFile = new ExcelFile();             ExcelWorksheet excWsheet = myExcelFile.Worksheets.Add("Hajan's worksheet");             excWsheet.Cells[0, 0].Value = "Pubs database Authors and Titles";             excWsheet.Cells[0, 0].Style.Borders.SetBorders(MultipleBorders.Bottom,System.Drawing.Color.Red,LineStyle.Thin);             excWsheet.Cells[0, 1].Style.Borders.SetBorders(MultipleBorders.Bottom, System.Drawing.Color.Red, LineStyle.Thin);                                      int numberOfColumns = 5; //the number of properties in the authorTitles we have             //for each column             for (int c = 0; c < numberOfColumns; c++)             {                 excWsheet.Columns[c].Width = 25 * 256; //set the width to each column                             }             //header row cells             excWsheet.Rows[2].Cells[0].Value = "Name";             excWsheet.Rows[2].Cells[1].Value = "Surname";             excWsheet.Rows[2].Cells[2].Value = "Title";             excWsheet.Rows[2].Cells[3].Value = "Price";             excWsheet.Rows[2].Cells[4].Value = "PubDate";             //bind authorTitles in the excel worksheet             int currentRow = 3;             foreach (AuthorTitles at in authorTitles)             {                 excWsheet.Rows[currentRow].Cells[0].Value = at.Name;                 excWsheet.Rows[currentRow].Cells[1].Value = at.Surname;                 excWsheet.Rows[currentRow].Cells[2].Value = at.Title;                 excWsheet.Rows[currentRow].Cells[3].Value = at.Price;                 excWsheet.Rows[currentRow].Cells[4].Value = at.PubDate;                 currentRow++;             }             //stylizing my excel file look             CellStyle style = new CellStyle(myExcelFile);             style.HorizontalAlignment = HorizontalAlignmentStyle.Left;             style.VerticalAlignment = VerticalAlignmentStyle.Center;             style.Font.Color = System.Drawing.Color.DarkRed;             style.WrapText = true;             style.Borders.SetBorders(MultipleBorders.Top                 | MultipleBorders.Left | MultipleBorders.Right                 | MultipleBorders.Bottom, System.Drawing.Color.Black,                 LineStyle.Thin);                                 //pay attention on this, we set created style on the given (firstRow, firstColumn, lastRow, lastColumn)             //in my example:             //firstRow = 2; firstColumn = 0; lastRow = authorTitles.Count+1; lastColumn = numberOfColumns-1; variable             excWsheet.Cells.GetSubrangeAbsolute(3, 0, authorTitles.Count+2, numberOfColumns-1).Style = style;             //save my excel file             myExcelFile.SaveXls(Server.MapPath(".") + @"/myFile.xls"); The AuthorTitles class: public class AuthorTitles {     public string Name { get; set; }     public string Surname { get; set; }     public string Title { get; set; }     public decimal? Price { get; set; }     public DateTime PubDate { get; set; } } The excel file will be generated in the root of your ASP.NET Web Application. The result is: There is a lot more you can do with this library. A set of good examples you have in the GemBox.Spreadsheet Samples Explorer application which comes together with the installation and you can find it by default in Start –> All Programs –> GemBox Software –> GemBox.Spreadsheet Samples Explorer. Hope this was useful for you. Best Regards, Hajan

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  • DTGridView losing content while scrolling

    - by Wim Haanstra
    I am using DTGridView from the DTKit by Daniel Tull. I implemented it in a very simple ViewController and the test I am doing is to place a button in the last row of the grid, which should add another row to the grid (and therefor moving the button to a row beneath it). The problem is, when I click the button a couple of times and then start scrolling, the grid seems to lose its content. As I am not completly sure this is a bug in the grid, but more in my code, I hope you guys can help me out and track down the bug. First I have my header file, which is quite simple, because this is a test: #import <UIKit/UIKit.h> #import "DTGridView.h" @interface TestController : UIViewController <DTGridViewDelegate, DTGridViewDataSource> { DTGridView* thumbGrid; } @end I declare a DTGridView, which will be my grid, where I want to put content in. Now, my code file: #import "TestController.h" @implementation TestController int rows = 1; - (NSInteger)numberOfRowsInGridView:(DTGridView *)gridView { return rows; } - (NSInteger)numberOfColumnsInGridView:(DTGridView *)gridView forRowWithIndex:(NSInteger)index { if (index == rows - 1) return 1; else return 3; } - (CGFloat)gridView:(DTGridView *)gridView heightForRow:(NSInteger)rowIndex { return 57.0f; } - (CGFloat)gridView:(DTGridView *)gridView widthForCellAtRow:(NSInteger)rowIndex column:(NSInteger)columnIndex { if (rowIndex == rows - 1) return 320.0f; else return 106.6f; } - (DTGridViewCell *)gridView:(DTGridView *)gridView viewForRow:(NSInteger)rowIndex column:(NSInteger)columnIndex { DTGridViewCell *view = [[gridView dequeueReusableCellWithIdentifier:@"thumbcell"] retain]; if (!view) view = [[DTGridViewCell alloc] initWithReuseIdentifier:@"thumbcell"]; if (rowIndex == rows - 1) { UIButton* btnLoadMoreItem = [[UIButton alloc] initWithFrame:CGRectMake(10, 0, 301, 57)]; [btnLoadMoreItem setTitle:[NSString stringWithFormat:@"Button %d", rowIndex] forState:UIControlStateNormal]; [btnLoadMoreItem.titleLabel setFont:[UIFont boldSystemFontOfSize:20]]; [btnLoadMoreItem setBackgroundImage:[[UIImage imageNamed:@"big-green-button.png"] stretchableImageWithLeftCapWidth:10.0 topCapHeight:0.0] forState:UIControlStateNormal]; [btnLoadMoreItem addTarget:self action:@selector(selectLoadMoreItems:) forControlEvents:UIControlEventTouchUpInside]; [view addSubview:btnLoadMoreItem]; [btnLoadMoreItem release]; } else { UILabel* label = [[UILabel alloc] initWithFrame:CGRectMake(10,0,100,57)]; label.text = [NSString stringWithFormat:@"%d x %d", rowIndex, columnIndex]; [view addSubview:label]; [label release]; } return [view autorelease]; } - (void) selectLoadMoreItems:(id) sender { rows++; [thumbGrid setNeedsDisplay]; } - (void)viewDidLoad { [super viewDidLoad]; thumbGrid = [[DTGridView alloc] initWithFrame:CGRectMake(0,0, 320, 320)]; thumbGrid.dataSource = self; thumbGrid.gridDelegate = self; [self.view addSubview:thumbGrid]; } - (void)viewDidUnload { [super viewDidUnload]; } - (void)dealloc { [super dealloc]; } @end I implement all the methods for the DataSource, which seem to work. The grid is filled with as many rows as my int 'rows' ( +1 ) has. The last row does NOT contain 3 columns, but just one. That cell contains a button which (when pressed) adds 1 to the 'rows' integer. The problem starts, when it starts reusing cells (I am guessing) and content start disappearing. When I scroll back up, the UILabels I am putting in the cells are gone. Is there some bug, code error, mistake, dumb-ass-move I am missing here? Hope anyone can help.

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  • tcpdf table header in each page

    - by DragoN
    i am using tcpdf to create pdf files with rows of table in the first page of pdf i display some info like : List of table .... and header of table after that i display the rows in table if there much rows it contiunes in the next page without the info [List of table... and header of table] i want to display the header of table only in the next pages here is my code $pdf->SetFont('aefurat', '', 15); $pdf->AddPage('P', 'A4'); $pdf->SetFontSize(17); $pdf->Cell(0, 13, 'List of the Byan Table,'C'); $pdf->SetFont('dejavusans', '', 14); $htmlpersian = 'In / Out List'; $pdf->WriteHTML($htmlpersian, true, 0, true, 0); $pdf->setRTL(false); $pdf->SetFontSize(11); $pdf->setRTL(true); Connect(); $resultsc = mysql_query("SELECT * FROM byan Order By Date "); while($r = mysql_fetch_array($resultsc)) { $printresult .= ' <tr> <td ><center>'.$r['Date'].'</center></td> <td ><center>'.$r['In'].'</center></td> <td ><center>'.$r['Out'].'</center></td> <td ><center>'.$r['Balance'].'</center></td> <td ><center>'.$r['Info'].'</center></td> <td ><center>'.$r['Number'].'</center></td> </tr>'; } $tbl = ' <table cellspacing="0" cellpadding="1" border="1" align="center"> <tr> <td style="width: 13%; background-color:black; color:white;"><center>Date</center></td> <td style="width: 11%; background-color:black; color:white;"><center>In</center></td> <td style="width: 11%; background-color:black; color:white;"><center>Out</center></td> <td style="width: 12%; background-color:black; color:white;"><center>Balance</center></td> <td style="width: 45%; background-color:black; color:white;"><center>Info</center></td> <td style="width: 11%; background-color:black; color:white;"><center>Number</center></td> </tr> '.$printresult.' </table> '; $pdf->writeHTML($tbl, true, false, true, false, ''); the output is First Page: List of the Byan Table In / Out List Table Header rows Second Page: Rows Third Page: Rows i want the output to be like that First Page: List of the Byan Table In / Out List Table Header Rows Second Page: Table Header Rows Third Page: Table Header Rows

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  • DTGridView losting content while scrolling

    - by Wim Haanstra
    I am using DTGridView from the DTKit by Daniel Tull. I implemented it in a very simple ViewController and the test I am doing is to place a button in the last row of the grid, which should add another row to the grid (and therefor moving the button to a row beneath it). The problem is, when I click the button a couple of times and then start scrolling, the grid seems to lose its content. As I am not completly sure this is a bug in the grid, but more in my code, I hope you guys can help me out and track down the bug. First I have my header file, which is quite simple, because this is a test: #import <UIKit/UIKit.h> #import "DTGridView.h" @interface TestController : UIViewController <DTGridViewDelegate, DTGridViewDataSource> { DTGridView* thumbGrid; } @end I declare a DTGridView, which will be my grid, where I want to put content in. Now, my code file: #import "TestController.h" @implementation TestController int rows = 1; - (NSInteger)numberOfRowsInGridView:(DTGridView *)gridView { return rows; } - (NSInteger)numberOfColumnsInGridView:(DTGridView *)gridView forRowWithIndex:(NSInteger)index { if (index == rows - 1) return 1; else return 3; } - (CGFloat)gridView:(DTGridView *)gridView heightForRow:(NSInteger)rowIndex { return 57.0f; } - (CGFloat)gridView:(DTGridView *)gridView widthForCellAtRow:(NSInteger)rowIndex column:(NSInteger)columnIndex { if (rowIndex == rows - 1) return 320.0f; else return 106.6f; } - (DTGridViewCell *)gridView:(DTGridView *)gridView viewForRow:(NSInteger)rowIndex column:(NSInteger)columnIndex { DTGridViewCell *view = [[gridView dequeueReusableCellWithIdentifier:@"thumbcell"] retain]; if (!view) view = [[DTGridViewCell alloc] initWithReuseIdentifier:@"thumbcell"]; if (rowIndex == rows - 1) { UIButton* btnLoadMoreItem = [[UIButton alloc] initWithFrame:CGRectMake(10, 0, 301, 57)]; [btnLoadMoreItem setTitle:[NSString stringWithFormat:@"Button %d", rowIndex] forState:UIControlStateNormal]; [btnLoadMoreItem.titleLabel setFont:[UIFont boldSystemFontOfSize:20]]; [btnLoadMoreItem setBackgroundImage:[[UIImage imageNamed:@"big-green-button.png"] stretchableImageWithLeftCapWidth:10.0 topCapHeight:0.0] forState:UIControlStateNormal]; [btnLoadMoreItem addTarget:self action:@selector(selectLoadMoreItems:) forControlEvents:UIControlEventTouchUpInside]; [view addSubview:btnLoadMoreItem]; [btnLoadMoreItem release]; } else { UILabel* label = [[UILabel alloc] initWithFrame:CGRectMake(10,0,100,57)]; label.text = [NSString stringWithFormat:@"%d x %d", rowIndex, columnIndex]; [view addSubview:label]; [label release]; } return [view autorelease]; } - (void) selectLoadMoreItems:(id) sender { rows++; [thumbGrid setNeedsDisplay]; } - (void)viewDidLoad { [super viewDidLoad]; thumbGrid = [[DTGridView alloc] initWithFrame:CGRectMake(0,0, 320, 320)]; thumbGrid.dataSource = self; thumbGrid.gridDelegate = self; [self.view addSubview:thumbGrid]; } - (void)viewDidUnload { [super viewDidUnload]; } - (void)dealloc { [super dealloc]; } @end I implement all the methods for the DataSource, which seem to work. The grid is filled with as many rows as my int 'rows' ( +1 ) has. The last row does NOT contain 3 columns, but just one. That cell contains a button which (when pressed) adds 1 to the 'rows' integer. The problem starts, when it starts reusing cells (I am guessing) and content start disappearing. When I scroll back up, the UILabels I am putting in the cells are gone. Is there some bug, code error, mistake, dumb-ass-move I am missing here? Hope anyone can help.

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  • Make c# matrix code faster

    - by Wam
    Hi all, Working on some matrix code, I'm concerned of performance issues. here's how it works : I've a IMatrix abstract class (with all matrices operations etc), implemented by a ColumnMatrix class. abstract class IMatrix { public int Rows {get;set;} public int Columns {get;set;} public abstract float At(int row, int column); } class ColumnMatrix : IMatrix { private data[]; public override float At(int row, int column) { return data[row + columns * this.Rows]; } } This class is used a lot across my application, but I'm concerned with performance issues. Testing only read for a 2000000x15 matrix against a jagged array of the same size, I get 1359ms for array access agains 9234ms for matrix access : public void TestAccess() { int iterations = 10; int rows = 2000000; int columns = 15; ColumnMatrix matrix = new ColumnMatrix(rows, columns); for (int i = 0; i < rows; i++) for (int j = 0; j < columns; j++) matrix[i, j] = i + j; float[][] equivalentArray = matrix.ToRowsArray(); TimeSpan totalMatrix = new TimeSpan(0); TimeSpan totalArray = new TimeSpan(0); float total = 0f; for (int iteration = 0; iteration < iterations; iteration++) { total = 0f; DateTime start = DateTime.Now; for (int i = 0; i < rows; i++) for (int j = 0; j < columns; j++) total = matrix.At(i, j); totalMatrix += (DateTime.Now - start); total += 1f; //Ensure total is read at least once. total = total > 0 ? 0f : 0f; start = DateTime.Now; for (int i = 0; i < rows; i++) for (int j = 0; j < columns; j++) total = equivalentArray[i][j]; totalArray += (DateTime.Now - start); } if (total < 0f) logger.Info("Nothing here, just make sure we read total at least once."); logger.InfoFormat("Average time for a {0}x{1} access, matrix : {2}ms", rows, columns, totalMatrix.TotalMilliseconds); logger.InfoFormat("Average time for a {0}x{1} access, array : {2}ms", rows, columns, totalArray.TotalMilliseconds); Assert.IsTrue(true); } So my question : how can I make this thing faster ? Is there any way I can make my ColumnMatrix.At faster ? Cheers !

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  • Why is SQLite3 using covering indices instead of the indices I created?

    - by Geoff
    I have an extremely large database (contacts has ~3 billion entries, people has ~280 million entries, and the other tables have a negligible number of entries). Most other queries I've run are really fast. However, I've encountered a more complicated query that's really slow. I'm wondering if there's any way to speed this up. First of all, here is my schema: CREATE TABLE activities (id INTEGER PRIMARY KEY, name TEXT NOT NULL); CREATE TABLE contacts ( id INTEGER PRIMARY KEY, person1_id INTEGER NOT NULL, person2_id INTEGER NOT NULL, duration REAL NOT NULL, -- hours activity_id INTEGER NOT NULL -- FOREIGN_KEY(person1_id) REFERENCES people(id), -- FOREIGN_KEY(person2_id) REFERENCES people(id) ); CREATE TABLE people ( id INTEGER PRIMARY KEY, state_id INTEGER NOT NULL, county_id INTEGER NOT NULL, age INTEGER NOT NULL, gender TEXT NOT NULL, -- M or F income INTEGER NOT NULL -- FOREIGN_KEY(state_id) REFERENCES states(id) ); CREATE TABLE states ( id INTEGER PRIMARY KEY, name TEXT NOT NULL, abbreviation TEXT NOT NULL ); CREATE INDEX activities_name_index on activities(name); CREATE INDEX contacts_activity_id_index on contacts(activity_id); CREATE INDEX contacts_duration_index on contacts(duration); CREATE INDEX contacts_person1_id_index on contacts(person1_id); CREATE INDEX contacts_person2_id_index on contacts(person2_id); CREATE INDEX people_age_index on people(age); CREATE INDEX people_county_id_index on people(county_id); CREATE INDEX people_gender_index on people(gender); CREATE INDEX people_income_index on people(income); CREATE INDEX people_state_id_index on people(state_id); CREATE INDEX states_abbreviation_index on states(abbreviation); CREATE INDEX states_name_index on states(name); Note that I've created an index on every column in the database. I don't care about the size of the database; speed is all I care about. Here's an example of a query that, as expected, runs almost instantly: SELECT count(*) FROM people, states WHERE people.state_id=states.id and states.abbreviation='IA'; Here's the troublesome query: SELECT * FROM contacts WHERE rowid IN (SELECT contacts.rowid FROM contacts, people, states WHERE contacts.person1_id=people.id AND people.state_id=states.id AND states.name='Kansas' INTERSECT SELECT contacts.rowid FROM contacts, people, states WHERE contacts.person2_id=people.id AND people.state_id=states.id AND states.name='Missouri'); Now, what I think would happen is that each subquery would use each relevant index I've created to speed this up. However, when I show the query plan, I see this: sqlite> EXPLAIN QUERY PLAN SELECT * FROM contacts WHERE rowid IN (SELECT contacts.rowid FROM contacts, people, states WHERE contacts.person1_id=people.id AND people.state_id=states.id AND states.name='Kansas' INTERSECT SELECT contacts.rowid FROM contacts, people, states WHERE contacts.person2_id=people.id AND people.state_id=states.id AND states.name='Missouri'); 0|0|0|SEARCH TABLE contacts USING INTEGER PRIMARY KEY (rowid=?) (~25 rows) 0|0|0|EXECUTE LIST SUBQUERY 1 2|0|2|SEARCH TABLE states USING COVERING INDEX states_name_index (name=?) (~1 rows) 2|1|1|SEARCH TABLE people USING COVERING INDEX people_state_id_index (state_id=?) (~5569556 rows) 2|2|0|SEARCH TABLE contacts USING COVERING INDEX contacts_person1_id_index (person1_id=?) (~12 rows) 3|0|2|SEARCH TABLE states USING COVERING INDEX states_name_index (name=?) (~1 rows) 3|1|1|SEARCH TABLE people USING COVERING INDEX people_state_id_index (state_id=?) (~5569556 rows) 3|2|0|SEARCH TABLE contacts USING COVERING INDEX contacts_person2_id_index (person2_id=?) (~12 rows) 1|0|0|COMPOUND SUBQUERIES 2 AND 3 USING TEMP B-TREE (INTERSECT) In fact, if I show the query plan for the first query I posted, I get this: sqlite> EXPLAIN QUERY PLAN SELECT count(*) FROM people, states WHERE people.state_id=states.id and states.abbreviation='IA'; 0|0|1|SEARCH TABLE states USING COVERING INDEX states_abbreviation_index (abbreviation=?) (~1 rows) 0|1|0|SEARCH TABLE people USING COVERING INDEX people_state_id_index (state_id=?) (~5569556 rows) Why is SQLite using covering indices instead of the indices I created? Shouldn't the search in the people table be able to happen in log(n) time given state_id which in turn is found in log(n) time?

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  • Hello Operator, My Switch Is Bored

    - by Paul White
    This is a post for T-SQL Tuesday #43 hosted by my good friend Rob Farley. The topic this month is Plan Operators. I haven’t taken part in T-SQL Tuesday before, but I do like to write about execution plans, so this seemed like a good time to start. This post is in two parts. The first part is primarily an excuse to use a pretty bad play on words in the title of this blog post (if you’re too young to know what a telephone operator or a switchboard is, I hate you). The second part of the post looks at an invisible query plan operator (so to speak). 1. My Switch Is Bored Allow me to present the rare and interesting execution plan operator, Switch: Books Online has this to say about Switch: Following that description, I had a go at producing a Fast Forward Cursor plan that used the TOP operator, but had no luck. That may be due to my lack of skill with cursors, I’m not too sure. The only application of Switch in SQL Server 2012 that I am familiar with requires a local partitioned view: CREATE TABLE dbo.T1 (c1 int NOT NULL CHECK (c1 BETWEEN 00 AND 24)); CREATE TABLE dbo.T2 (c1 int NOT NULL CHECK (c1 BETWEEN 25 AND 49)); CREATE TABLE dbo.T3 (c1 int NOT NULL CHECK (c1 BETWEEN 50 AND 74)); CREATE TABLE dbo.T4 (c1 int NOT NULL CHECK (c1 BETWEEN 75 AND 99)); GO CREATE VIEW V1 AS SELECT c1 FROM dbo.T1 UNION ALL SELECT c1 FROM dbo.T2 UNION ALL SELECT c1 FROM dbo.T3 UNION ALL SELECT c1 FROM dbo.T4; Not only that, but it needs an updatable local partitioned view. We’ll need some primary keys to meet that requirement: ALTER TABLE dbo.T1 ADD CONSTRAINT PK_T1 PRIMARY KEY (c1);   ALTER TABLE dbo.T2 ADD CONSTRAINT PK_T2 PRIMARY KEY (c1);   ALTER TABLE dbo.T3 ADD CONSTRAINT PK_T3 PRIMARY KEY (c1);   ALTER TABLE dbo.T4 ADD CONSTRAINT PK_T4 PRIMARY KEY (c1); We also need an INSERT statement that references the view. Even more specifically, to see a Switch operator, we need to perform a single-row insert (multi-row inserts use a different plan shape): INSERT dbo.V1 (c1) VALUES (1); And now…the execution plan: The Constant Scan manufactures a single row with no columns. The Compute Scalar works out which partition of the view the new value should go in. The Assert checks that the computed partition number is not null (if it is, an error is returned). The Nested Loops Join executes exactly once, with the partition id as an outer reference (correlated parameter). The Switch operator checks the value of the parameter and executes the corresponding input only. If the partition id is 0, the uppermost Clustered Index Insert is executed, adding a row to table T1. If the partition id is 1, the next lower Clustered Index Insert is executed, adding a row to table T2…and so on. In case you were wondering, here’s a query and execution plan for a multi-row insert to the view: INSERT dbo.V1 (c1) VALUES (1), (2); Yuck! An Eager Table Spool and four Filters! I prefer the Switch plan. My guess is that almost all the old strategies that used a Switch operator have been replaced over time, using things like a regular Concatenation Union All combined with Start-Up Filters on its inputs. Other new (relative to the Switch operator) features like table partitioning have specific execution plan support that doesn’t need the Switch operator either. This feels like a bit of a shame, but perhaps it is just nostalgia on my part, it’s hard to know. Please do let me know if you encounter a query that can still use the Switch operator in 2012 – it must be very bored if this is the only possible modern usage! 2. Invisible Plan Operators The second part of this post uses an example based on a question Dave Ballantyne asked using the SQL Sentry Plan Explorer plan upload facility. If you haven’t tried that yet, make sure you’re on the latest version of the (free) Plan Explorer software, and then click the Post to SQLPerformance.com button. That will create a site question with the query plan attached (which can be anonymized if the plan contains sensitive information). Aaron Bertrand and I keep a close eye on questions there, so if you have ever wanted to ask a query plan question of either of us, that’s a good way to do it. The problem The issue I want to talk about revolves around a query issued against a calendar table. The script below creates a simplified version and adds 100 years of per-day information to it: USE tempdb; GO CREATE TABLE dbo.Calendar ( dt date NOT NULL, isWeekday bit NOT NULL, theYear smallint NOT NULL,   CONSTRAINT PK__dbo_Calendar_dt PRIMARY KEY CLUSTERED (dt) ); GO -- Monday is the first day of the week for me SET DATEFIRST 1;   -- Add 100 years of data INSERT dbo.Calendar WITH (TABLOCKX) (dt, isWeekday, theYear) SELECT CA.dt, isWeekday = CASE WHEN DATEPART(WEEKDAY, CA.dt) IN (6, 7) THEN 0 ELSE 1 END, theYear = YEAR(CA.dt) FROM Sandpit.dbo.Numbers AS N CROSS APPLY ( VALUES (DATEADD(DAY, N.n - 1, CONVERT(date, '01 Jan 2000', 113))) ) AS CA (dt) WHERE N.n BETWEEN 1 AND 36525; The following query counts the number of weekend days in 2013: SELECT Days = COUNT_BIG(*) FROM dbo.Calendar AS C WHERE theYear = 2013 AND isWeekday = 0; It returns the correct result (104) using the following execution plan: The query optimizer has managed to estimate the number of rows returned from the table exactly, based purely on the default statistics created separately on the two columns referenced in the query’s WHERE clause. (Well, almost exactly, the unrounded estimate is 104.289 rows.) There is already an invisible operator in this query plan – a Filter operator used to apply the WHERE clause predicates. We can see it by re-running the query with the enormously useful (but undocumented) trace flag 9130 enabled: Now we can see the full picture. The whole table is scanned, returning all 36,525 rows, before the Filter narrows that down to just the 104 we want. Without the trace flag, the Filter is incorporated in the Clustered Index Scan as a residual predicate. It is a little bit more efficient than using a separate operator, but residual predicates are still something you will want to avoid where possible. The estimates are still spot on though: Anyway, looking to improve the performance of this query, Dave added the following filtered index to the Calendar table: CREATE NONCLUSTERED INDEX Weekends ON dbo.Calendar(theYear) WHERE isWeekday = 0; The original query now produces a much more efficient plan: Unfortunately, the estimated number of rows produced by the seek is now wrong (365 instead of 104): What’s going on? The estimate was spot on before we added the index! Explanation You might want to grab a coffee for this bit. Using another trace flag or two (8606 and 8612) we can see that the cardinality estimates were exactly right initially: The highlighted information shows the initial cardinality estimates for the base table (36,525 rows), the result of applying the two relational selects in our WHERE clause (104 rows), and after performing the COUNT_BIG(*) group by aggregate (1 row). All of these are correct, but that was before cost-based optimization got involved :) Cost-based optimization When cost-based optimization starts up, the logical tree above is copied into a structure (the ‘memo’) that has one group per logical operation (roughly speaking). The logical read of the base table (LogOp_Get) ends up in group 7; the two predicates (LogOp_Select) end up in group 8 (with the details of the selections in subgroups 0-6). These two groups still have the correct cardinalities as trace flag 8608 output (initial memo contents) shows: During cost-based optimization, a rule called SelToIdxStrategy runs on group 8. It’s job is to match logical selections to indexable expressions (SARGs). It successfully matches the selections (theYear = 2013, is Weekday = 0) to the filtered index, and writes a new alternative into the memo structure. The new alternative is entered into group 8 as option 1 (option 0 was the original LogOp_Select): The new alternative is to do nothing (PhyOp_NOP = no operation), but to instead follow the new logical instructions listed below the NOP. The LogOp_GetIdx (full read of an index) goes into group 21, and the LogOp_SelectIdx (selection on an index) is placed in group 22, operating on the result of group 21. The definition of the comparison ‘the Year = 2013’ (ScaOp_Comp downwards) was already present in the memo starting at group 2, so no new memo groups are created for that. New Cardinality Estimates The new memo groups require two new cardinality estimates to be derived. First, LogOp_Idx (full read of the index) gets a predicted cardinality of 10,436. This number comes from the filtered index statistics: DBCC SHOW_STATISTICS (Calendar, Weekends) WITH STAT_HEADER; The second new cardinality derivation is for the LogOp_SelectIdx applying the predicate (theYear = 2013). To get a number for this, the cardinality estimator uses statistics for the column ‘theYear’, producing an estimate of 365 rows (there are 365 days in 2013!): DBCC SHOW_STATISTICS (Calendar, theYear) WITH HISTOGRAM; This is where the mistake happens. Cardinality estimation should have used the filtered index statistics here, to get an estimate of 104 rows: DBCC SHOW_STATISTICS (Calendar, Weekends) WITH HISTOGRAM; Unfortunately, the logic has lost sight of the link between the read of the filtered index (LogOp_GetIdx) in group 22, and the selection on that index (LogOp_SelectIdx) that it is deriving a cardinality estimate for, in group 21. The correct cardinality estimate (104 rows) is still present in the memo, attached to group 8, but that group now has a PhyOp_NOP implementation. Skipping over the rest of cost-based optimization (in a belated attempt at brevity) we can see the optimizer’s final output using trace flag 8607: This output shows the (incorrect, but understandable) 365 row estimate for the index range operation, and the correct 104 estimate still attached to its PhyOp_NOP. This tree still has to go through a few post-optimizer rewrites and ‘copy out’ from the memo structure into a tree suitable for the execution engine. One step in this process removes PhyOp_NOP, discarding its 104-row cardinality estimate as it does so. To finish this section on a more positive note, consider what happens if we add an OVER clause to the query aggregate. This isn’t intended to be a ‘fix’ of any sort, I just want to show you that the 104 estimate can survive and be used if later cardinality estimation needs it: SELECT Days = COUNT_BIG(*) OVER () FROM dbo.Calendar AS C WHERE theYear = 2013 AND isWeekday = 0; The estimated execution plan is: Note the 365 estimate at the Index Seek, but the 104 lives again at the Segment! We can imagine the lost predicate ‘isWeekday = 0’ as sitting between the seek and the segment in an invisible Filter operator that drops the estimate from 365 to 104. Even though the NOP group is removed after optimization (so we don’t see it in the execution plan) bear in mind that all cost-based choices were made with the 104-row memo group present, so although things look a bit odd, it shouldn’t affect the optimizer’s plan selection. I should also mention that we can work around the estimation issue by including the index’s filtering columns in the index key: CREATE NONCLUSTERED INDEX Weekends ON dbo.Calendar(theYear, isWeekday) WHERE isWeekday = 0 WITH (DROP_EXISTING = ON); There are some downsides to doing this, including that changes to the isWeekday column may now require Halloween Protection, but that is unlikely to be a big problem for a static calendar table ;)  With the updated index in place, the original query produces an execution plan with the correct cardinality estimation showing at the Index Seek: That’s all for today, remember to let me know about any Switch plans you come across on a modern instance of SQL Server! Finally, here are some other posts of mine that cover other plan operators: Segment and Sequence Project Common Subexpression Spools Why Plan Operators Run Backwards Row Goals and the Top Operator Hash Match Flow Distinct Top N Sort Index Spools and Page Splits Singleton and Range Seeks Bitmaps Hash Join Performance Compute Scalar © 2013 Paul White – All Rights Reserved Twitter: @SQL_Kiwi

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  • Performance Enhancement in Full-Text Search Query

    - by Calvin Sun
    Ever since its first release, we are continuing consolidating and developing InnoDB Full-Text Search feature. There is one recent improvement that worth blogging about. It is an effort with MySQL Optimizer team that simplifies some common queries’ Query Plans and dramatically shorted the query time. I will describe the issue, our solution and the end result by some performance numbers to demonstrate our efforts in continuing enhancement the Full-Text Search capability. The Issue: As we had discussed in previous Blogs, InnoDB implements Full-Text index as reversed auxiliary tables. The query once parsed will be reinterpreted into several queries into related auxiliary tables and then results are merged and consolidated to come up with the final result. So at the end of the query, we’ll have all matching records on hand, sorted by their ranking or by their Doc IDs. Unfortunately, MySQL’s optimizer and query processing had been initially designed for MyISAM Full-Text index, and sometimes did not fully utilize the complete result package from InnoDB. Here are a couple examples: Case 1: Query result ordered by Rank with only top N results: mysql> SELECT FTS_DOC_ID, MATCH (title, body) AGAINST ('database') AS SCORE FROM articles ORDER BY score DESC LIMIT 1; In this query, user tries to retrieve a single record with highest ranking. It should have a quick answer once we have all the matching documents on hand, especially if there are ranked. However, before this change, MySQL would almost retrieve rankings for almost every row in the table, sort them and them come with the top rank result. This whole retrieve and sort is quite unnecessary given the InnoDB already have the answer. In a real life case, user could have millions of rows, so in the old scheme, it would retrieve millions of rows' ranking and sort them, even if our FTS already found there are two 3 matched rows. Apparently, the million ranking retrieve is done in vain. In above case, it should just ask for 3 matched rows' ranking, all other rows' ranking are 0. If it want the top ranking, then it can just get the first record from our already sorted result. Case 2: Select Count(*) on matching records: mysql> SELECT COUNT(*) FROM articles WHERE MATCH (title,body) AGAINST ('database' IN NATURAL LANGUAGE MODE); In this case, InnoDB search can find matching rows quickly and will have all matching rows. However, before our change, in the old scheme, every row in the table was requested by MySQL one by one, just to check whether its ranking is larger than 0, and later comes up a count. In fact, there is no need for MySQL to fetch all rows, instead InnoDB already had all the matching records. The only thing need is to call an InnoDB API to retrieve the count The difference can be huge. Following query output shows how big the difference can be: mysql> select count(*) from searchindex_inno where match(si_title, si_text) against ('people')  +----------+ | count(*) | +----------+ | 666877 | +----------+ 1 row in set (16 min 17.37 sec) So the query took almost 16 minutes. Let’s see how long the InnoDB can come up the result. In InnoDB, you can obtain extra diagnostic printout by turning on “innodb_ft_enable_diag_print”, this will print out extra query info: Error log: keynr=2, 'people' NL search Total docs: 10954826 Total words: 0 UNION: Searching: 'people' Processing time: 2 secs: row(s) 666877: error: 10 ft_init() ft_init_ext() keynr=2, 'people' NL search Total docs: 10954826 Total words: 0 UNION: Searching: 'people' Processing time: 3 secs: row(s) 666877: error: 10 Output shows it only took InnoDB only 3 seconds to get the result, while the whole query took 16 minutes to finish. So large amount of time has been wasted on the un-needed row fetching. The Solution: The solution is obvious. MySQL can skip some of its steps, optimize its plan and obtain useful information directly from InnoDB. Some of savings from doing this include: 1) Avoid redundant sorting. Since InnoDB already sorted the result according to ranking. MySQL Query Processing layer does not need to sort to get top matching results. 2) Avoid row by row fetching to get the matching count. InnoDB provides all the matching records. All those not in the result list should all have ranking of 0, and no need to be retrieved. And InnoDB has a count of total matching records on hand. No need to recount. 3) Covered index scan. InnoDB results always contains the matching records' Document ID and their ranking. So if only the Document ID and ranking is needed, there is no need to go to user table to fetch the record itself. 4) Narrow the search result early, reduce the user table access. If the user wants to get top N matching records, we do not need to fetch all matching records from user table. We should be able to first select TOP N matching DOC IDs, and then only fetch corresponding records with these Doc IDs. Performance Results and comparison with MyISAM The result by this change is very obvious. I includes six testing result performed by Alexander Rubin just to demonstrate how fast the InnoDB query now becomes when comparing MyISAM Full-Text Search. These tests are base on the English Wikipedia data of 5.4 Million rows and approximately 16G table. The test was performed on a machine with 1 CPU Dual Core, SSD drive, 8G of RAM and InnoDB_buffer_pool is set to 8 GB. Table 1: SELECT with LIMIT CLAUSE mysql> SELECT si_title, match(si_title, si_text) against('family') as rel FROM si WHERE match(si_title, si_text) against('family') ORDER BY rel desc LIMIT 10; InnoDB MyISAM Times Faster Time for the query 1.63 sec 3 min 26.31 sec 127 You can see for this particular query (retrieve top 10 records), InnoDB Full-Text Search is now approximately 127 times faster than MyISAM. Table 2: SELECT COUNT QUERY mysql>select count(*) from si where match(si_title, si_text) against('family‘); +----------+ | count(*) | +----------+ | 293955 | +----------+ InnoDB MyISAM Times Faster Time for the query 1.35 sec 28 min 59.59 sec 1289 In this particular case, where there are 293k matching results, InnoDB took only 1.35 second to get all of them, while take MyISAM almost half an hour, that is about 1289 times faster!. Table 3: SELECT ID with ORDER BY and LIMIT CLAUSE for selected terms mysql> SELECT <ID>, match(si_title, si_text) against(<TERM>) as rel FROM si_<TB> WHERE match(si_title, si_text) against (<TERM>) ORDER BY rel desc LIMIT 10; Term InnoDB (time to execute) MyISAM(time to execute) Times Faster family 0.5 sec 5.05 sec 10.1 family film 0.95 sec 25.39 sec 26.7 Pizza restaurant orange county California 0.93 sec 32.03 sec 34.4 President united states of America 2.5 sec 36.98 sec 14.8 Table 4: SELECT title and text with ORDER BY and LIMIT CLAUSE for selected terms mysql> SELECT <ID>, si_title, si_text, ... as rel FROM si_<TB> WHERE match(si_title, si_text) against (<TERM>) ORDER BY rel desc LIMIT 10; Term InnoDB (time to execute) MyISAM(time to execute) Times Faster family 0.61 sec 41.65 sec 68.3 family film 1.15 sec 47.17 sec 41.0 Pizza restaurant orange county california 1.03 sec 48.2 sec 46.8 President united states of america 2.49 sec 44.61 sec 17.9 Table 5: SELECT ID with ORDER BY and LIMIT CLAUSE for selected terms mysql> SELECT <ID>, match(si_title, si_text) against(<TERM>) as rel  FROM si_<TB> WHERE match(si_title, si_text) against (<TERM>) ORDER BY rel desc LIMIT 10; Term InnoDB (time to execute) MyISAM(time to execute) Times Faster family 0.5 sec 5.05 sec 10.1 family film 0.95 sec 25.39 sec 26.7 Pizza restaurant orange county califormia 0.93 sec 32.03 sec 34.4 President united states of america 2.5 sec 36.98 sec 14.8 Table 6: SELECT COUNT(*) mysql> SELECT count(*) FROM si_<TB> WHERE match(si_title, si_text) against (<TERM>) LIMIT 10; Term InnoDB (time to execute) MyISAM(time to execute) Times Faster family 0.47 sec 82 sec 174.5 family film 0.83 sec 131 sec 157.8 Pizza restaurant orange county califormia 0.74 sec 106 sec 143.2 President united states of america 1.96 sec 220 sec 112.2  Again, table 3 to table 6 all showing InnoDB consistently outperform MyISAM in these queries by a large margin. It becomes obvious the InnoDB has great advantage over MyISAM in handling large data search. Summary: These results demonstrate the great performance we could achieve by making MySQL optimizer and InnoDB Full-Text Search more tightly coupled. I think there are still many cases that InnoDB’s result info have not been fully taken advantage of, which means we still have great room to improve. And we will continuously explore the area, and get more dramatic results for InnoDB full-text searches. Jimmy Yang, September 29, 2012

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  • ???Past Image(pi)

    - by todd.bao(at)oracle.com
    Past Image???RAC??????????,????????????????????????????????,Past Image??????????,?????????????????,?????????????????,??????????????(pi)?????????????????Past Image,????????????:HR.EMPLOYEES??100????101?????5????88???????????????,???????????# ??1: ?????????SYS@RAC1//scripts> select inst_id,status from gv$bh where file#=5 and block#=88;no rows selected# ??1???(???Steve King, ????24000????)SYS@RAC1//scripts> update hr.employees set salary=1 where employee_id=100;1 row updated.# ??2: ????1??xcur????????????,?????????SYS@RAC1//scripts> select inst_id,dirty,status from gv$bh where file#=5 and  block#=88;   INST_ID + D + STATUS---------- + - + -------         1 + Y + xcur1 row selected.# ??2???SYS@RAC2//scripts> update hr.employees set salary=2 where employee_id=101;1 row updated.# ??3: ????2?,?????1??pi??Past Image,???????????????????????SYS@RAC1//scripts> select inst_id,dirty,status from gv$bh where file#=5 and  block#=88;   INST_ID + D + STATUS---------- + - + -------         1 + Y + pi         2 + Y + xcur2 rows selected.# ??1???SYS@RAC1//scripts> update hr.employees set salary=3 where employee_id=100;1 row updated.# ??4: ????1?,?????2???1???????2???????1???????SYS@RAC1//scripts> select inst_id,dirty,status from gv$bh where file#=5 and  block#=88;   INST_ID + D + STATUS---------- + - + -------         1 + Y + pi         1 + Y + xcur         2 + Y + pi3 rows selected.# ??2????SYS@RAC2//scripts> update hr.employees set salary=4 where employee_id=101;1 row updated.# ??5: ????2?,??????????????,DBWR??,??????,??(pi)?????????????(cr)??????????????????????????SYS@RAC1//scripts> select inst_id,dirty,status from gv$bh where file#=5 and  block#=88;   INST_ID + D + STATUS---------- + - + -------         1 + N + cr         1 + N + cr         2 + Y + xcur3 rows selected.# ?????1???SYS@RAC1//scripts> update hr.employees set salary=5 where employee_id=100;1 row updated.# ??6: ????1?,?????2????????????????,?????????SYS@RAC1//scripts> select inst_id,dirty,status from gv$bh where file#=5 and  block#=88;   INST_ID + D + STATUS---------- + - + -------         1 + Y + xcur         1 + N + cr         1 + N + cr         2 + Y + pi4 rows selected.# ??2???SYS@RAC2//scripts> update hr.employees set salary=6 where employee_id=101;1 row updated.# ??7: ????2?,?????1?2????1???????2?????????????4,????????????????SYS@RAC1//scripts> select inst_id,dirty,status from gv$bh where file#=5 and  block#=88;   INST_ID + D + STATUS---------- + - + -------         1 + Y + pi         2 + Y + pi         2 + Y + xcur3 rows selected.# ??1???SYS@RAC1//scripts> update hr.employees set salary=7 where employee_id=100;1 row updated.# ??8: ????1?,?????2?1????2???????1????????????2????????????????????????????????????(????????)????SYS@RAC1//scripts> select inst_id,dirty,status from gv$bh where file#=5 and  block#=88;   INST_ID + D + STATUS---------- + - + -------         1 + Y + pi         1 + Y + xcur         2 + Y + pi         2 + N + cr4 rows selected.??????????, ?xcur??????????:??????xcur????pi?????pi?(?????)???cr?,???cr?????,pi????????????????????????????:?????????????A?B?A:SYS@RAC1//scripts> run  1  begin  2  for i in 1..100000 loop  3  update hr.employees set salary=i where employee_id=100;  4  end loop;  5* end;B:SYS@RAC2//scripts> run  1  begin  2  for i in 1..100000 loop  3  update hr.employees set salary=i where employee_id=101;  4  end loop;  5* end;?????????,???5???88?????buffer cache???????:SYS@RAC2//scripts> select count(*) from gv$bh where file#=5 and block#=88;  COUNT(*)----------       4121 row selected.??409?????????(cur):SYS@RAC2//scripts> select count(*) from gv$bh where file#=5 and block#=88 where status='cr';  COUNT(*)----------       4091 row selected.1????????(xcur):SYS@RAC2//scripts> select count(*) from gv$bh where file#=5 and block#=88 where status='xcur';  COUNT(*)----------           11 row selected.??...2??????--????(pi)??????????SYS@RAC1//scripts> select inst_id,dirty,status from gv$bh where file#=5 and block#=88 and status='pi';   INST_ID + D + STATUS---------- + - + -------         1 + Y + pi         2 + Y + pi2 rows selected.????,???RAC??????????????(cr)?,????????????????????????xcur?pi??cr??????pi?????? ?????????,???????????pi???cr?,?????????cr???,???xcur???????,pi??????xcur?,[email protected]

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