Number Of Columns And Performance
Apr 25, 2007
Hi,
I'm designing a new database and I have a doubt in which surely you
can help me.
I'm storing in this database historical data of some measurements and
the system in constantly growing, new measurements are added every
day.
So, I have to set some extra columns in advance, so space is available
whenever is needed and the client doesn't have to modify the structure
in SQL server.
The question is: the more columns I add "just in case", the slower the
SQL reads the table?
Of course the "empty" columns are not included in any query until they
have some valid data inside.
Will I have better performance if I configure only the columns being
used at the moment, without any empty columns?
Thanks in advance.
Ignacio
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Dec 28, 2007
Hi,
I have a denormalized table (done so with reason) with around 40 columns. I would never have to retrieve data for all of those columns together.
I haven't done any performance measurements yet but just wondering if anyone has ready answer to this: Will there be a performance degradation if I retrieve data from a table with many columns, even if not all columns are referred in the query? (for making it simple, lets assume that all or varchar type of columns, I just want to find out if performance degrades if there are too many columns in table)
Thanks in advance,
Sandeep
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Sep 24, 2007
Hi
I want to enter rows into a table having more number of columns
For example : I have one employee table having columns (name ,address,salary etc )
then, how can i enter 100 employees data at a time ?
Suppose i am having my data in .txt file (or ) in .xls
( SQL Server 2005)
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Jun 5, 2007
Hi,
I am currently designing a SSIS package to integrate data into a data warehouse fact table. This fact table has about 70 columns among which 17 are foreign keys for dimension tables.
To insert data in that table, I have to make several transformations and lookups. Given the fact that the lookups I have to make are a little complicated, I have about 70 tasks in my Data Flow.
I know it's a lot, but I can't find a way to make it simpler. It seems I really need all these tasks.
Now, the problem is that every new action I try to make on the package takes a lot of time. At design time, everything is very slow. My processor is eavily loaded each time I change a single setting in one of the tasks, and executing the package in debug mode takes for ages. If I take a look at the size of my package file on disk, it's more than 3MB.
Hence my question : Are there any limitations in terms of number of columns or number of tasks that can be processed within a Data Flow ?
If not, then do you have any idea why it's so slow ?
Thanks in advance for any answer.
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Sep 10, 2007
I am working on a Statistical Reporting system where:
Data Repository: SQL Server 2005
Business Logic Tier: Views, User Defined Functions, Stored Procedures
Data Access Tier: Stored Procedures
Presentation Tier: Reporting ServicesThe end user will be able to slice & dice the data for the report by
different organizational hierarchies
different number of layers within a hierarchy
select a organization or select All of the organizations with the organizational hierarchy
combinations of selection criteria, where this selection criteria is independent of each other, and also differeBelow is an example of 2 Organizational Hierarchies:
Hierarchy 1
Country -> Work Group -> Project Team (Project Team within Work Group within Country)
Hierarchy 2
Client -> Contract -> Project (Project within Contract within Client)Based on 2 different Hierarchies from above - here are a couple of use cases:
Country = "USA", Work Group = "Network Infrastructure", Project Team = all teams
Country = "USA", Work Group = all work groups
Client = "Client A", Contract = "2007-2008 Maint", Project = "Accounts Payable Maintenance"
Client = "Client A", Contract = "2007-2008 Maint", Project = all
Client = "Client A", Contract = allI am totally stuck on:
How to implement the data interface (Stored Procs) to the Reports
Implement the business logic to handle the different hierarchies & different number of levelsI did get help earlier in this forum for how to handle a parameter having a specific value or NULL value (to select "all")
(WorkGroup = @argWorkGroup OR @argWorkGrop is NULL)
Any Ideas? Should I be doing this in SQL Statements or should I be looking to use Analysis Services.
Thanks for all your help!
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Apr 11, 2008
Hi guys,
I have 2 tables:
Unit( unit_id integer, unit_name varchar(20) )
Part( part_id integer, part_name varchar(20) )
Then I have a join table between the two
Unit_Part( unit_id, part_id )
Each unit NAME and part NAME is unique. So what kind of performance would I be losing if I were to do something like:
PROCEDURE addPartToUnit( VARCHAR(20) sPartName, VARCHAR(20) sUnitName )
-- Now in this procedure i'll just get the id's via the names from a select statement
Versus
PROCEDURE addPartToUnit( nPartId INTEGER, nUnitId INTEGER )
-- In this proc, i directly input the primary keys of the table so no lookup is necessary
The reason is that I would like for developers to be able to write code without having to know the id's.
What do you think?
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Jan 25, 2008
Hi gurus, I'm creating a web application where I will have a large number of tables (between 10k and 20k), this is done for the sake of scalability as tables will be moved to different database servers as the application grows and also for performance (smaller indexes). I'm worried though how having a large number of tables could affect the performance of SQL Server as the application will start on one single database server. I tried to find some resources on that on the internet but couldn't find any.
I would really appreciate if you can give me some advice and if you have any good links that would be great...
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Jan 25, 2008
Hi gurus, I'm creating a web application where I will have a large number of tables (between 10k and 20k), this is done for the sake of scalability as tables will be moved to different database servers as the application grows and also for performance (smaller indexes). I'm worried though how having a large number of tables could affect the performance of SQL Server as the application will start on one single database server. I tried to find some resources on that on the internet but couldn't find any.
I would really appreciate if you can give me some advice and if you have any good links that would be great...
Waleed Eissa
http://www.waleedeissa.com
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May 21, 2007
does anyone know what the maximum number of columns is that an SQL table can contain ?
i seem to remember that in the past it was something like 200 columns max, but i don't know whether that has changed with newer versions of SQL Server
looking at the spec for SQL Server 2000 i see a maximum of 1024 columns per base table - am i right in interpreting this to mean the maximum is now 1024 columns or is a base table different from an SQL table ?
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Oct 1, 2014
Is there a performance limit on the number of indexes per table / database ? With Filtered indexes there appear to be many more opportunities for more finely defined, and therefore smaller indexes resulting in many more indexes on a single table.
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Jun 2, 2005
when using sorred procedure to create a temporary table is it possable to base the number of columns in that table on another variable?
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Jan 11, 2006
How can I determine the number of columns in a table?
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Sep 4, 2007
While Running a SSIS package after migrating it from DTS to SSIS , in MS SQL Server 2005 ,
it gives error while execution :
DTS_DTSTASK_DATAPUMPTASK_2
The number of columns is incorrect.verify the column metadata is valid.
"OLEDB Destination "(22) Failed the pre execution phase and returned error code 0xC0202025
Thanks for the response .....
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Sep 11, 2007
Hi,
I'm using ADO 2.8 in a vb.net code. The .Net framework version is 1.1 and windows server 2003.
I'm firing a query that result in 256 columns and few hundred rows. Here is the snapshot of the code
adoRs = New ADODB.Recordset
With adoRs
.CursorLocation = CursorLocationEnum.adUseClient ' adUseClient
.ActiveConnection = adoCn
.CursorType = CursorTypeEnum.adOpenStatic ' adOpenStatic
.LockType = LockTypeEnum.adLockBatchOptimistic ' adLockBatchOptimistic
.Open(strSQL)
End With
The returned record set is empty with all the the 256 columns name. Could anyone shed light why it is returning empty recordset. Is there any limitation on number of columns that a recordset can hold.
Thanks in advance.
With regards
Ganesh
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May 4, 2001
I have a db which I have little control over most of it's makeup because of the vendor supplied tools. We currently have over 700 tables and 19000 columns. Has anyone seen a problem or saturation pont with these kinds of numbers? The database delivered to the clients will be from 2-50 gig depending on the site. I can probably through hardware at problems, but if anyone has been down this road any suggestions are appreciated.
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Dec 12, 2007
Hi
We are using the SQL Server 2005 Full Text Service. The data is not huge, but the kind of data is that each record is small and there are a large number of records. There are 35 million records now with 11 GB of data and about 1.6 GB of FT catalog on the table. This is expected to grow to at least 10 times the size of this data. The issue is with FTS taking a long time to return results when the number of hits (rows) getting returned from FTS is large for some searches, it takes a very long time. With the same data & catalog, those full text queries for less common words return timely. The nature of the problem doesnt allow us to only have top results. We need all the results. So it’s not about the size of data but the number of results getting returned from FT. (As the catalog is inverted). The machine is dual processor with 4 GB RAM.
I am considering splitting the table and hence the catalog and using multiple servers to do full text searches in smaller catalogs. Is there any other way this issue can be solved ?
If splitting is the only way, can you give me an idea as to what is a statistical/standard limit to the number of search results/cataog size as which FTS gives good results
Thanks in advance
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Jun 29, 2006
hi.i am using ms sql server 2000. can somebody tell me what the code would be to remove all the values in a given column and replace them with the associated number of the row with each execution. so, if i have a column:nums|1||2||3||4|and somebody deletes record |2|i would like the nums colum to update to|1||2||3|not:|1||3||4|it seems simple but i am having a hard time with this. how is it done?thanks.
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Jul 16, 2001
We are looking at developing a new app with a SQL Server db. As such, we're all newbies.
What is the maximum number of columns I can put in a SQL Server table?
Thanks in advance.
Bob Anderson
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Jun 15, 2005
Hi,
I have a sql query which gives me the result set with lots of columns and rows.
a b c allocated unallocated
- ------ 75458702 0484095809
------- 534534 8743857
------- 953459034 90584395
i have to find of which is the smallest number in both allocated and unallocated columns -
here in this case
it would be 534534.
how do i do this ?
Thanks
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Apr 24, 2008
Hi,
In short:
I want my following problem to work with a LIKE instead of exact match and if possible be faster. (currently 4s)
Problem:
I got a set of rows with varchar(50), spread out over multiple tables.
All those tables relate to a central Colour table.
For each of the columns, I want to match the values with a set of strings I insert and then return a set of Colour.Id
E.g: input: 'BLACK', 'MERCEDES', '1984'
Would return colour ids "025864", 45987632", "65489" and "63249"
Because they have a colour name containing 'BLACK' or are on a car from 'MERCEDES' or are used in '1984'.
Current Situation:
I) Create a table containing all possible values
CREATE TABLE dbo.CommonSearch(
id int IDENTITY (1, 1) NOT NULL,
clr_id int,
keyWord varchar(40),
fieldType varchar(25)
And fill it with all the values (671694 rows)
)
II) Stored Procedure to cut a string up into a table:
CREATE FUNCTION dbo.SplitString
(
@param varchar(50),
@splitChar char = ''
)
RETURNS
@T TABLE (keyWord varchar(50))
AS
BEGIN
WHILE LEN( @param ) > 0 BEGIN
declare @val varchar(50)
IF CHARINDEX( @splitChar, @param ) > 0
SELECT @val = LEFT( @param, CHARINDEX( @splitChar, @param ) - 1 ) ,
@param = RIGHT( @param, LEN( @param ) - CHARINDEX( @splitChar, @param ) )
ELSE
SELECT @val = @param, @param = SPACE(0)
INSERT INTO @T values (@val)
END
RETURN
END
III)Stored Procedure to query the first table with the second one
CREATE PROCEDURE [dbo].[GetCommonSearchResultForTabDelimitedStrings]
@keyWords varchar(255) = ''
AS
BEGIN
SET NOCOUNT ON;
select clr_id, keyWord, fieldType
from dbo.commonSearch
where keyWord in (select * from splitString(@keyWords, ''))
END
So, how can I use a LIKE statement in the IN statement of the last query.
Furthermore, I was wondering if this is the best sollution to go for.
Are there any better methods? Got any tuning tips to squeeze out an extra second?
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Mar 20, 2007
Keshka writes "I'm using function fnParseString form http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=76033 in some of my sp.
it's very helpfull, but my question is if there is a way to split variable into columns if I don't know how many columns I'll have? It could be 1 or 2 or 3 and etc.
Thanks"
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Jul 20, 2005
I have table1 and table2.In table1 I have a column of numbers, numbers1.In table2 I have a column of numbers, numbers2.I'd like to select the highest number represented in either column.Example:table1:column1--------------345565643656555676table2:column2--------------3456564556456456456456The number I would want would be 56456 since it's the largest numberout of all combined.How can I get that number with one select statement?--[ Sugapablo ][ http://www.sugapablo.com <--music ][ http://www.sugapablo.net <--personal ][ Join Bytes! <--jabber IM ]
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May 2, 2007
We are trying to use the Import/export wizard to load a text file to a SQL Server 2005 database. The input file has a variable number of columns per row. For example, the first row has 3 columns, the second has 7, the third has 3, etc. The number of columns varies from 2 to 9 in the input file. The columns are separated by an uptick (`) and the rows are terminated by {CR}{LF}. We are using code page 1252. On processing, the wizard reads the first row (with 3 columns) ok, but then assumes all the other rows have 3 columns and parses the rows accordingly, ignoring the field and row terminators.
The process worked fine with SQL Server 2000. Is there some setting that we are missing, or some configuration on the database that we should be checking?
Thank You
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Feb 6, 2008
Hi, I need to update a number of columns in a number of tables - I just don't know how many. In this case, I am updating all varchar fields and nvarchar fields to be converted to lower case. The problem is that the table structure is amended over time as columns are added programmatically, so I do not know which tables have which columns and if so which of them are varchars.
I can get a table of which fields I need to update using:
SELECT TABLE_NAME, COLUMN_NAME, ORDINAL_POSITION, DATA_TYPE
INTO tblTempLCase
FROM information_schema.columns
WHERE DATA_TYPE LIKE '%varchar'
and I can do the update with UPDATE tblxxx SET column = LOWER(column)
But what I don't know is how to step through my temporary table and do the updates. I can do it in ASP.NET, but that involves pushing commands and data between ASP and SQL, and will be too slow. How do I do it in SQL?
Thanks,
Dave Stephens
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Feb 6, 2008
Hi,
I need to update a number of columns within a number of tables - I just don't know how many. In this case, I want to convert all varchar and nvarchar columns to lower-case versions of themselves. The problem is that the table structure is changed programatically, and so at any point in time I cannot be certain what fields are in which table, and what data type they are.
I know that I can get a lit of columns using:
SELECT TABLE_NAME, COLUMN_NAME, ORDINAL_POSITION, DATA_TYPE
INTO tblTempLCase
FROM information_schema.columns
WHERE DATA_TYPE LIKE '%varchar'
and do the update using:
UPDATE tblABCDE SET column = LOWER(column).
In ASP.NET I can pull in this temporary table using a SQL Data Adapter, and then step through the records to formulate the UPDATE statements and execute them all. However, I hope that this is possible in SQL too, so that I do not have to keep firing data/commands between ASP and SQL, as it should be quicker, and is also neater.
If so, how do you do it?
Thanks,
Dave Stephens
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Feb 6, 2008
Hi,
I need to update a number of columns within a number of tables - I just don't know how many. In this case, I want to convert all varchar and nvarchar columns to lower-case versions of themselves. The problem is that the table structure is changed programatically, and so at any point in time I cannot be certain what fields are in which table, and what data type they are.
I know that I can get a lit of columns using:
SELECT TABLE_NAME, COLUMN_NAME, ORDINAL_POSITION, DATA_TYPE
INTO tblTempLCase
FROM information_schema.columns
WHERE DATA_TYPE LIKE '%varchar'
and do the update using:
UPDATE tblABCDE SET column = LOWER(column).
In ASP.NET I can pull in this temporary table using a SQL Data Adapter, and then step through the records to formulate the UPDATE statements and execute them all. However, I hope that this is possible in SQL too, so that I do not have to keep firing data/commands between ASP and SQL, as it should be quicker, and is also neater.
If so, how do you do it?
Thanks,
Dave Stephens
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Apr 7, 2008
I have a database hosted by GoDaddy. Recently they made some changes to the interface and upgraded to SQL Server 2008. One or the other has made it impossible to access my data in one table.
The table is quite large in terms of the numbers of elements. Each row describes a dog and all the elements are components of the description. There are (I would guess) more than 50 elements all together.
When I try to search the database, the query form goes beyond the top and bottom of the page. I can scroll the database but the search tool (which lies atop the data) does not scroll. The result is that I can't activate the search.
I've tried about 10 machines. All with IE6 display this fault. Machines with IE7 do not. I've tried various screen resolutions on the machines with IE6. That doesn't help.
I've checked other tables in the database. No problem.
In short, there's nothing I can do. I can't edit my data and GoDaddy says, "Tough."
Is there a limit on the number of columns (elements) in a table in SQL Server 2008?
Eric
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Jun 20, 2007
I am upgrading from Access, where you can only have 10 fields in a primary key or unique index. Is this also the limit in SQL Server? If not, what is the limit?
Thanks for any help on this.
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Mar 21, 2007
HI all !
I am having a bit of a problem trying to limit a number of columns in a matrix appearing on a page.
At the moment, I have a dataset that lists the month and the mail packages that were sent during the month
The matrix works great HOWEVER, if there were more than 8 months in the matrix columns, it does not break and would make the page look like a huge landscape page.
I am trying to limit the number of columns appearing (this is the months column) on the matrix so that the pages stay in a potrait position. IE: every 8 columns appear on one page. Is there an option or an expression I could use in the Matrix ?
Thanks!
BErnard Ong
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Jun 3, 2015
I am adding a table within my vb.net program using New datatable(tblname) function, then adding 22 columns (col01 to col22) to this table using .columns.add (colname) function without any error.The program however throws an exception when trying to assign a value to column number 14 (col14) saying this column does not belong to table tblname. Assigning a value from col01 to col13 is working fine.Is there a limitation on number of columns can be added to a table using code?
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Jul 17, 2007
I am creating a report that uses the Matrix control. I need to display a fixed number of columns (5). In my query, I am returning the top 5 rows of data. However, in some cases there are less than 5 rows of data returned from the dataset. Is there a way to force the number of columns displayed in the matrix control and to populate with some text (such as "n/a") if no data is available?
Thanks!
ads
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Jan 6, 2006
I am doing a mass update of our SQL script files by adding dbo.to all references to the tables.The code is also adding dbo. in front of existing lines of codethat are like this:SELECT CLIENT.FIRSTNAME,CLIENT.LASTNAMEFROM CLIENT....The mass update is causing this to become:SELECT dbo.CLIENT.FIRSTNAME,dbo.CLIENT.LASTNAMEFROM dbo.CLIENT....My goal is to see FROM dbo.CLIENTbut even the column names are getting the "dbo."added, so my question is if there's any performanceloss or any other side effect if I end up all my columnswith a preceeding "dbo."?Thank you
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Aug 14, 2001
I've got a database with an unknown number of columns. Hence, the column names are also unknown. What's the easiest SQL to present the values in each column and the column headings?
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