Load Method Of A Datatable Sometimes So Slow
Jun 27, 2011
The project is a web app in ASP/VB.net. The issue is that some pages are mind-boggingly slow. After trying to track down the bottleneck, it was discovered to be the load method when filling a datatable with query results.
We are using an Oracle database and queries are executed in stored procedures. As an example, we have a relatively simple select statement within a procedure which returns 2 columns with 6 rows which was determined to take about 0.015 seconds to execute. However it takes on average 7 seconds to load the OracleDataReader into a datatable - a ridiculous amount of time for such a small record set. After messing around with the query, I found that a simple decode statement appeared to be causing the issue. The decode statement is used similar to as follows[code]...
The iBln variable is simply a number being passed in to act as a boolean variable for determining which column should be between two dates. If I comment this decode statement out and make it simply "column1 BETWEEN iDate1 and iDate2" then the load method takes no time at all as it should, signifying that it is indeed the decode statement causing issues.
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Mar 2, 2010
rsReturn = New DataSet()
objCommand.CommandTimeout = 240
Using objadapter As New OleDbDataAdapter(objCommand)
[code].....
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Jan 19, 2010
I fill a dataset using fill() method of sqldataadapter. The select query call a user defined function in it. My problem is that when I run this query in sqlDataAdapter , the fill() method take about 70 Sec. to give output but if I run the same query in Enterprise Manager or in Query Analyzer it gives output within a 1 or 2 Sec.
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Mar 16, 2009
I have a program in where I need to loop though the entire dataset.datatable. I takes a long time. What is the alternative I can use to do the some job but faster?
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Oct 13, 2009
Something happened to my VS2005 setup and now the first time load for F1 can take a full minute to load. I think the last significant thing I did was install an add-in for ESRI ArcExplorer. I uninstalled that add-in but help is stil VERY slow to start.Does anyone recognize the problem and have a simple fix?
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Jul 1, 2010
I am using VB.Net with Access DB. Main form is a Parent MDI. Each form when open first time is slow. It takes noticible time. But, from second time it becomes very fast.
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May 10, 2011
I am loading data from query into a dataadapter and then into a dataset.the datadridview datasource is the set to the dataset.but it takes too long to load the data into the datagridview.
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Nov 13, 2009
I'm working on a larger VB application (framework v3.5) where the compile time continues to get slower and slower the larger it grows. It currently takes about 7 minutes to compile just the extensions project. We have other similar projects in C# that don't experience the slow compile time.
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Mar 22, 2012
After I RemoveAt my payList, it appear very slow in edit form, but in new form no problem.How to make it faster. [code]
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May 20, 2010
I am trying to create an application. I am using MDI forms method to navigate throughout the application. However, when a user clicks a button to create a new child or when the application execute this code
[Code]...
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Nov 9, 2010
I wrote last week about a problem with an MDI program that had a large number of forms (each with a large number of controls on it) that was "sluggish" in loading and in switching between the child forms.I've attached an example program in VS2008 (though the actual app is VB2010)Rather than show the hardware control application with all of the text fields, and picture boxes acting as indicators, I made a simple program to show the point. This is exaggerated as this just loads 2000 or so text boxes on a form. In the real app I have ~ 200 assorted controls per form of picture boxes, scroll bars, text boxes, labels etc. Also, there is a large full screen .jpeg as the back ground of each form. All are generated at run time and are placed on the form in the New call of each form. (as in the sample attached)main issue seems to be the methodology I use to switch between child forms. I make the current form .visible = false, and the next.visible = true. I have used this as it "keeps the place" on each page if the user has scrolled or is looking at one section of the form. When the next form .visible = true happens I see the controls added in a "machine gun" fashion instead of all at once.
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Feb 24, 2012
I'm trying to get value from Datatable after Select Method.Select Method should return only one record.
Dim y As DataTable = CType(HttpContext.Current.Session("tb"), DataTable)
Dim products = y.[Select]("StnID" = "'" + stnID + "'")
Dim size = DirectCast(Products(0)("Shape"), String)
if I replace products with y--(DirectCast(y.Rows(0)("Shape"), String), it works.(which is before Select method, so it's useless) products is datarow object and I can't seem to get the value same way as datatable.How do I get value from datarows?
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Apr 21, 2009
I have this function that returns a DataTable :
Public Shared Function GetDataTable(ByVal PageSize As Integer, ByVal CurrentPagea As Integer) As DataTable
Dim dtData As New DataTable
dtData = da_Book_Content.GetDataContent()[code].....
On a page, I have DataList to display the data. It works but I want to implement the paging feature. How do I do that with so I be able to use Linq lazy loading feature ?
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Feb 19, 2012
Is there a function to write this in DataTable Select method in VB.net?SQL Query that I would like useSELECT id from mytable where id in ('a','b','c')
I have this code to create query but it would be nice if I can use IN clause
For Each typeitem In shapecb.Items
If Stntypeitem.Selected = True Then
[code].....
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Mar 28, 2010
I want to filter a virtual table (DataTable) and return only matching items into another datatable which eventualy is the datasource of a datagrid. The datagrid displays the result. The purpose is to reduce the network traffic while still providing the function. So as type on the textbox provided, the virtual table which was earlier populated by a disconnected Ado ADO connection, is re-queried and filtered into the new datatable.
how to go about this. It is a windows application and i am using dot net 3.5, VB 2008.
Here is my code:
Dim filtDT
If MYQDT.Rows.Count <= 0 Then
MsgBox("The data is been cleared")
[Code]....
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Jun 5, 2011
how to create ascending order datatable in asp.net without sorting method
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Sep 9, 2011
How do i use Datatable.select method to select only those rows where a specific column value is blank?
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Nov 22, 2011
I'm having the datatable with three columns, i need to return the rows in which the third column having the null values.
ie., I need to do like this below mentioned coding,
Dim rows As DataRow() = ds.Tables("Tablename").Select("col3 is null")
Is it possible? if no, anyone tell me the way to get the results.
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Apr 16, 2009
I found the following example on [URL] Unfortunately, I need it in VB and it's using some constructs that neither I nor the automated code converters reciognize. Anyone out there know how this should be written in VB.Net? (the problem spot is the "select new {...")
PeopleDataSet ds = new PeopleDataSet();
using (PeopleDataContext context = new PeopleDataContext())
{
[Code].....
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Jul 7, 2009
[code]...Load DataReader into DataTable
This code return an error, and with breakpoint i get this error on the items line:
"Item = In order to evaluate an indexed property, the property must be qualified and the arguments must be explicitly supplied by the user."
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Jul 14, 2010
vb.net 2005
Here is one attempt:
Dim myRow As BurnerService.OEBSContractBatchesRow
Dim myDate As Nullable(Of DateTime)
myRow = Me.BurnerService.OEBSContractBatches.AddOEBSContractBatchesRow( _
[Code].....
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Feb 3, 2011
ds.Tables.Add("OpenTickets") ds.Tables("OpenTickets") = ds.Tables("AllTickets").Copy()
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Jan 21, 2012
I have some VB code like
Dim data As DataTable = DataAccess.ExecuteDataSet("AuthenticateWebServiceClient" _
, New SqlParameter("@ClientID", ClientId) _
, New SqlParameter("@Password", Password) _[code]....
Except PrepareSPCommand isn't recognized by VS. Does anyone know the correct way to convert this function to C#.
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Apr 9, 2009
Jst recently i came across the select() method of data table and felli n love with it instantaneously.
Basically I want query the data table on a date field, unfortunately the format of the date string returned from y database in to data-table and the date string i'm passing as inputs are different.
How can i make sure that the data is compared irrespective of the formats ? Can I use something like SqlParameters whoes data type is date for comparison ??
this is what i'm tying :
dim dat as date = "#1/3/2009#"
dt.select("StzDate ='" & dat "'")
entry in datateable dt : StzDate : 3/1/2009 12:00:000
Am I do'in something wrong ??
Also, can anyone redirect me to some site where I can learn a bit more about passing parameters to the select statement,etc...
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Dec 17, 2009
VB.Net 2005 SQL server 2005
I have a project I have a dataset that contains tables In the dataset designer, each table has a defaiult FILL command set. I have draged and droped my table as a grid onto my form VB automatically sets up the table adapter, and binding source to make it all work.
in my code, is placed in the form load routine, a tableadapter.fill(dataset.datatable)
Here is my dilemma. The data in my table may have 100's of thousands or rows.
I have presented the user with a front end that allows for filterring and selecting based on several columns. reguardless of how many rows the result set contains, there will always be the same columns in the dataset.
Because there are so many combinations of select query, i do not want to make 20 or 30 custom fillby's in the dataset. I want to make an addhoc select query and have the binding source and table adapters work as expected. I have created a query called "FillByCustom" in the dataset designer attached to the DataTable Adapter section.
My question is this.
If i build a select query that returns the desired rows, how do i place it into the adapter in place of the FILLBYCUSTOM select command, such that it all works as expected?
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Apr 19, 2010
I want to use FindBy method to return record in a datatable and show the fields in the corresponding textboxes and other controls. The DataTable in which i am looking is already bound to these controls, maybe when I use the following code (which is not working correctly, hence this thread) the fields will show up rightaway?
{
Dim MoviesRow As New_Movie_DatabaseDataSet.My_Movies_TableRow
MoviesRow = New_Movie_DatabaseDataSet.My_Movies_TableDataTable.FindByID(ComboBox1.Text)
}
This is the error:
reference to a non-shared member requires an object reference.
I wanted to import Microsoft.Practices.ObjectBuilder2 but that does not work either.
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Apr 6, 2010
Scenario is this; I've a sqldatareader query that seems to be returning nothing when I try to convert the sqldatareader to a datatable using datatable.load.So I debug into it, I grab the verbose SQL query before it goes into the sqldatareader, just to make sure it's formatted correctly. I copy and paste this into SQL server to run it and see if it returns anything. It does, one row.I go back to visual studio and let the program continue, I create a datatable and try to load the sqldatareader but it just returns an empty reader. I'm baffled as to what's going on. [code] Ok I've done a loop to count the rows of the datareader before using the datatable.load method. In my test query I'm getting 4 rows (the correct amount) in the datareader, as soon as I use the datatable.load method it says the datatable is empty, what's going on?! So it seems a datareader is a one-way thing, iterate through it to get the row count and it's essentially empty as far as any other bit of code is concerned. Didn't realise it was forward only and wouldn't 'reset' once read through.
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May 7, 2012
I'm trying to load a datable into a datagridview, but column1 ("date") should be converted to a datetime, so I can sort it when I click on the datagridview header
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Mar 27, 2009
I have returned xml data in a variable and need to loop through the returned xml and pull certain data from select nodes.
I was thinking the best way would be to load into a dataset (or datatable) and loop through that.
I also have the xmlschema. What's the best way to code this?
I thought I could do something like so but it gives me the following error: DataTable 'newdt' does not match to any DataTable in source.
[Code].....
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Feb 17, 2011
I'm getting this error on a datatable.Load() :
Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.
If I use a DataAdapter it works fine, using the same SQL query.
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