I am trying to understand how the data in sql server is stored and
also regarding fill factor and page splitting.
1) My first question what is the difference between Index pages and
Data pages.
and how are they different for clustered and non clustered indexes and
heap tables.
2) What is the relation between index and data pages.
2) BOL says that fill factor is used to define the amount of free
space on each page of index. I am confused here what does index pages
and data pages contain
for clustered/non clustered/heap tables.
3) Why does page splits occur and do they occur due to the lack of
space in index or data pages?
Hello all,SQL 2000 on Windows 2000. If I go into all tasks, maintenance plan, itgives me an option to reorganize data and index pages. When I check onit, it populates the line "change free space per page percentage to" andputs in 10 in there. Is this the default for free space? Is it thedata pages that will have 10% free space or just the index pages? Aredata and index on the same pages?Thanks,Raziq.*** Sent via Developersdex http://www.developersdex.com ***
in microsoft doc there is written on the topic of BP Extensions with SSD's in SQL Server 2014: only clean pages are written to disk... does this mean data pages that have not been modified yet? or also those data pages that have already been modified, and where log has finished writing and the transaction has been marked as commited??
why are there clean data pages being written to L2 cache to make space for other not modified pages? I mean, shoudnt they be modified first, before letting other unmodified data pages into the Cache? I mean they have still to be modified..that makes no sense to me to page them out and page them in again just for other data pages...
GreetingsFor performance reasons I am trying to determine how often the pages inthe index split due to inserts. Are there any records in the 'sys' tables,etc. Thanx
is there a step by step paper to get there? here is what i need to consider. I Iwill have many customers that will need their own set of records and access pages "branded for their company" each customer will have many clients. I am hosting this application on a windows 2003 server with SQL 2005 server enterprise.
I am using windows authentication, I have created a username in windows, then i added the windows user in SQL management studio in security, granted "DB Read" and "DB write" and again under the database security tab. still from the web authentication fails. i must be nissing a step or two?
I expect to set up a username for each database as i setup new customers.
Dear All,I have developed a Data Access Page with Access as a project. It isconnected to a SQL-Server database. I try to edit the data in the table andam not able to do so. I might be missing some permissions. I have changeda number. What am I missing?Thanks in advance.Jeff Magouirk
I in a table or partition, the first page is an IAM-Page if I'm not wrong, this page keeps track of the extents. In the first extent to where the "first_iam_page" points to, the extent is a mixed extent, therefore the pages can be from different tables or partitions, correct? How does my IAM-Page map the right pages to the corresponding table? the following extents are all uniform of one table type, so I guess it doesnt matter then. But n, how does it keep track of which pages belong to which tables in the first extent?
My second question is, the first IAM-Page is obviously an IAM-Page, but there are also GAM , SGAM and PFS Page files... where are they stored? Because when I create a table and insert a big value(8000) into it, it reserves 16KB for that table, one for the IAM-page, and one for the first data-page. But where can I find the GAM,SGAM and PFS page files? or are they not page files, just some other structures?
I have a question about loading data on the page lode event. The question is more conceptual then how to.
Using C#, I would like to make a call to a SQL 2000 Server, with the use of a stored procedure return one row with eleven fields. Then use the data to fill five different controls. There is no manipulation of the data it is just presented as information. With a DataReader and the GetValues method using the resultant array I can fill the controls (or can I), or with a DataSet and the Load method do the same thing. Now this code can be placed in the code behind page or it can be implemented in a class. This is the only page that uses this combination of fields and controls; however I would think a more generic call to the data could be made then pick and chose the fields as needed. What process makes the most sense? Is what I just described even possible (as yet I haven’t tried it)?
As always thanks in advance for any thoughts, comments, and suggestions.
IF (SELECT OBJECT_ID('t1')) IS NOT NULLDROP TABLE t1GOCREATE TABLE t1 (c1 INT, c2 INT)DECLARE @n INTSET @n = 1WHILE @n <= 454BEGININSERT INTO t1 VALUES (@n, @n)SET @n = @n + 1ENDSELECT name, indid, CASE indidWHEN 0 THEN 'Table'WHEN 1 THEN 'Clustered Index'ELSE 'Nonclustered Index'END AS Type,dpages, rowcntFROM sysindexesWHERE id = OBJECT_ID('T1')name indid Type dpages rowcnt---- ----- ---- ------ ------NULL 0 Table 2 454I have a table containing 454 rows of two columnsof type INT with each being 4 bytesc1 int = 4 bytes+c2 int = 4 bytes=8 bytes per rowIf I entered 454 rows : 454 * 8 = 3,632 byteseach SQL Page is 8KB = 8 * 1024 bytes= 8,192 bytesa data page header takes the first 96 bytesleaving 8096 bytes for data and row offsets.Each record uses a row offset at the end of the pageconsisting of 2 bytes. 454 * 2 = 908 bytes.8096 - 3632 - 908 = 3,556 bytes. Should this befree data bytes?For a heap table, does SQL add an internal uniqueidentifiercolumn also? or my question is when does SQL adda uniqueidentifier? I am reading Inside SQL 2000 andtrying to understand a few things.A uniqueidentifier of 4 bytes gets added when a clustered indexexists but it is NOT a UNIQUE clustered index. AND onlyif duplicate record is added those two records only geta uniqueidentifier value.But in my example it's a heap table with no indexes. Evenon a heap table with no indexes a ROWID or Uniqueidentifierget added? Based on the INSERT statement above allvalues are unique.So what am I missing to understand why 453 rowsmake one data page to be used whereas 454 rowsmake two data pages to be used?Thank you
please explain the differences btween this logical & phisicall operations that we can see therir graphical icons in execution plan tab in Management Studio
Hello All,I have a SQLDataSource "sdsX" which has four records. There is a DataList "dlX" which is binded to this SQLDataSource "sdsX". Now I want that my datalist "dlX" take third record of "sdsX" as its first element. Is there any property which can be used.Thanks
Hi all,I have a table called PTRANS with few columns (see create script below).I have created a view on top that this table VwTransaction (See below)I can now run this query without a problem:select * from dbo.VwTransactionwhereAssetNumber = '101001' andTransactionDate <= '7/1/2003'But when I create an index on the PTRANS table using the command below:CREATE INDEX IDX_PTRANS_CHL# ON PTRANS(CHL#)The same query that ran fine before, fails with the error:Server: Msg 242, Level 16, State 3, Line 1The conversion of a char data type to a datetime data type resulted inan out-of-range datetime value.I can run the same query by commeting out the AssetNumber clause and itworks fine. I can also run the query commenting out the TransactionDatecolumn and it works fine. But when I have both the conditions in theWHERE clause, it gives me this error. Dropping the index solves theproblem.Can anyone tell me why an index would cause a query to fail?Thanks a lot in advance,AmirCREATE TABLE [PTRANS] ([CHL#] [varchar] (100) COLLATE SQL_Latin1_General_CP1_CI_AS NULL ,[CHCENT] [numeric](2, 0) NOT NULL ,[CHYYMM] [numeric](4, 0) NOT NULL ,[CHDAY] [numeric](2, 0) NOT NULL ,[CHTC] [char] (2) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL) ON [PRIMARY]GOCREATE VIEW dbo.vwTransactionsASSELECT CONVERT(datetime, dbo.udf_AddDashes(REPLICATE('0', 2 -LEN(CHCENT)) + CONVERT(varchar, CHCENT) + REPLICATE('0', 4 -LEN(CHYYMM))+ CONVERT(varchar, CHYYMM) + REPLICATE('0', 2 -LEN(CHDAY)) + CONVERT(varchar, CHDAY)), 20) AS TransactionDate,CHL# AS AssetNumber,CHTC AS TransactionCodeFROM dbo.PTRANSWHERE (CHCENT <> 0) AND (CHTC <> 'RA')*** Sent via Developersdex http://www.developersdex.com ***Don't just participate in USENET...get rewarded for it!
Hi there, I'm using a query to fetch data from a table where one of the criteria is IN(...) clause for the key column of the table.Now the data being retrieved is ordered by the key column of the table even though I haven't specified any order by clause. I want to know if there a way in which the data being fetched is in the order of my IN(...) clause.
Hi Champs I am importing huge amout of row into a DW, that I then want to build Cubes from.
This process is slow, as SQL insists of concurrently building an index, whil loading. Is there a possebility to delay the build of Index to After the data is loaded into the DW?
Hi, I want to ask a basic question, that is IN WHAT ORDER A CLUSTERED INDEX SORT THE DATA IN THE COLUMN????
Somewhere in the MSDN library I read the following line: "A clustered index physically sorts the table's contents in the order of the specified index columns"
But Sorting means it will be in ASCENDING ORDER (ASC) or It will be in DESCENDING ORDER (DESC) So my question is lets suppose a column on which the cluistered index is defined and it contains character data liek abcd so in wht order it will sort the data alphabetically ASC or DESC or If the same above case with integer type of values, if column having integer values then in wht order the data in the table will be sorted.
If I have a table that I want to create a clustered index on. For example sake, say that I have 2 columns in the table. Col1 is char(2), col2 is text (or image). If I create a clustered index on col1, the database needs 1.2% times the size of the table to create the clustered index. Does this include the size of col2, being that text and image data is stored in a separate page chain....?
I was going through the book by Kalen Delaney where she has mentioned the following paragpraph in Chapter 7 (Index Internals):
Many documents describing SQL Server indexes will tell you that the clustered index physically stores the data in sorted order. This can be misleading if you think of physical storage as the disk itself. If a clustered index had to keep the data on the actual disk in a particular order, it could be prohibitively expensive to make changes. If a page got too full and had to be split in two, all the data on all the succeeding pages would have to be moved down. Sorted order in a clustered index simply means that the data page chain is logically in order.
Then I read the book on SQL Server 2000 (on Perf Tuning) by Ken England. He says the clustered index stores data in physical order and any insert means moving the data physically. Also the same statement is echoed on the net by many articles.
What is the truth? How are really clustered index stored? What does physical order in the above statement really mean?
Anyone know the syntax and function to create a self incrementing index whilst extracting data? I'm using the Derived Column tool. The extract will be a full extract everytime, not incremental. Thanks.
I have read recommendations about searching encrypted data. Typically, they involve creating a MAC (message authentication code) table. One of the elements of that table is a HASH of the encrypted data (plus a Mac key) that is used as an index for searching. Is that HASH as secure as the encrypted data itself, or is this approach less secure? If it is less secure, then may I assume that approach is the only feasible way to search data encrypted by nondeterministic algorithms?
Hi everyone, If I have a table with some indexes on the foriegn keys and these indexes are heavily fragmented (80%+), is it normal for queries to return incorrect results?
For example if I had a table called Customer( CustID, Name) and Orders (OrderID, CustID, Product, Date). Lets say I have a non clustered index on CustID in Orders table, and the clustered indexes are Customer.CustID and Orders.OrderID
If the non clusterd index on Orders.CustID becomes heavily fragmented and I am querying the Orders table with TSQL "SELECT * FROM Orders where CustID = @CustID" I sometimes get missing data or incorrect results. In one case all orders for a particular year were missing, but if I queried using OderID they were returned. Rebuilding the index fixed the problem.
I know the index should be rebuilt or reorganized depending on the fragmentation but if one happened to become this fragmented should it start returning incorrect data?
i have one col in a nonclusted index which is bigint 8 bytes follwoing result shows min_record_size_in_bytes and max_record_size_in_bytes is 20 that is 12+8 page size is 8 kB. does that mean a record will use 20 bytes in a page or it will only use the space equalent to data stored in the col.what i have seen is page count is same weather i put some data in the col or null
We have a typical issue with Column Store Index, we have a procedure which does 2 activities - Switch & Reverse Switch
Switch: 1. Fetch the Partitions needed to be switched 2. Switch the data from Main Table to Switch table 2. Disable the Column store on Switch table
SSIS Package: 3. Load data to Switch (Insert / Update)
Reverse Switch: 4. Enable the Switch 5. Switch back the data from Switch table to Main table
Issue: Some time the Column store is not getting disabled, and the package fails complaining try disabling the Column store index and try loading data.
If we re-run the procedure, the column store gets disabled.
I am trying to create a sample table in the Azure SQL Data warehouse but its giving me a syntax error Incorrect syntax near the keyword 'CLUSTERED'.
CREATE TABLE [dbo].[FactInternetSales] ( [ProductKey] int NOT NULL , [OrderDateKey] int NOT NULL , [CustomerKey] int NOT NULL , [PromotionKey] int NOT NULL
I am using Full Text Index to index emails stored in BLOB column in a table. Index process parses stored emails, and, if there is one or more files attached to the email these documents get indexed too. In result when I'm querying the full text index for a word or phrase I am getting reference to the email containing the word of phrase if interest if the word was used in the email body OR if it was used in any document attached to the email.
How to distinguish in a Full Text query that the result came from an embedded document rather than from "main" document? Or if that's not possible how to disable indexing of embedded documents?
My goal is either to give a user an option if he or she wants to search emails (email bodies only) OR emails AND documents attached to them, or at least clearly indicate in the returned result the real source where the word or phrase has been found.
Web Base application or PDA devices use to initiate the order from all over the country. The issue is this table is not Partioned but good HP with 30 GB RAM is installed. this is main table that receive 18,0000 hits or more. All brokers and users are using this table to see the status of their order.
The always search by OrderID, or ClientID or order_SubNo, or enter any two like (Client_ID+Order_Sub_ID) or any combination.
Query takes to much time when ever server receive more querys. some orther indexes are also created on the same table like (OrderDate, OrdCreate Date and Status)
My Question are:-
Q1. IF Person "A" query to DB on Client_ID, then what Index will use ? (If any one do Query on any two combination like Client_ID+Order_ID, So what index will be uesd.? How does MS-SQL SERVER deal with these kind of issues.?
Q2. If i create 3 more indexes on ClientID, ORderID and OrdersubID. will this improve the performance of query.if person "A" search record on orderNo so what index will be used. (Mind it their would be 3 seprate indexes for Each PK columns) and composite-Clustered index is also available.?
Q3. I want to check what indexes has been used? on what search?
Q4. How can i check what table was populated when, or last date of update (DML)?
My Limitation is i Dont Create a Partioned table. I dont have permission to do it.
In Teradata we had more than 4 tb record of CRM data with no issue. i am not new baby in db line but not expert in sql server 2003.
My SSIS package is running very slow taking so much time to execute, One task is taking 2hr for inserting 100k records, i have disabled unused index still it is taking time.I am rebuilding/Refreshing indexes and stats once in month if i try to execute on daily basis will it improve my SSIS Package performance?
hello friends i have table1 and 200 coulumn of table1 :) i have 647.600 records. i entered my records to table1 with for step to code lines in one day :) i select category1 category2 and category3 with select code but i have just one index.. it is productnumber and it is primarykey..So my select code lines is so slow.. it is 7-9 second.. how can i select in 0.1 second ? Should i create index for category1 and category2 and category3 ? But i dont know create index.. My select code lines is below.. Could you learn me and show me index for it ?? or Could you learn me and show me fast Select code lines and index or etc ??? Also my search code line have a dangerous releated to attaching table1 with hackers :) cheersi send 3 value of treview1 node and childnode and child.childnode to below page.aspx :) Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load If Not Me.IsPostBack Then If Request("TextBox1") IsNot Nothing ThenTextBox1.Text = Request("TextBox1") End If If Request("TextBox2") IsNot Nothing ThenTextBox2.Text = Request("TextBox2") End If If Request("TextBox3") IsNot Nothing ThenTextBox3.Text = Request("TextBox3") End If End If Dim searchword As String If Request("TextBox3") = "" And Request("TextBox2") = "" Then searchword = "Select * from urunlistesi where kategori= '" & Request("TextBox1") & "'" End If If Request("TextBox3") = "" Then searchword = "Select * from urunlistesi where kategori= '" & Request("TextBox1") & "' and kategori1= '" & Request("TextBox2") & "'" End If If Request("TextBox3") <> "" And Request("TextBox2") <> "" And Request("TextBox1") <> "" Then searchword = "Select * from urunlistesi where kategori= '" & Request("TextBox1") & "' and kategori1= '" & Request("TextBox2") & "' and kategori2= '" & Request("TextBox3") & "'" End If SqlDataSource1.SelectCommand = searchword End Sub
I'm running a merge replication on a sql2k machine to 6 sql2k subscribers. Since a few day's only one of the merge agents fail's with the following error:
The merge process could not retrieve generation information at the 'Subscriber'. The index entry for row ID was not found in index ID 3, of table 357576312, in database 'PBB006'.
All DBCC CHECKDB command's return 0 errors :confused: I'm not sure if the table that's referred to in the message is on the distribution side or the subscribers side? A select * from sysobjects where id=357576312 gives different results on both sides . .
Hi everyone, When we create a clustered index firstly, and then is it advantageous to create another index which is nonclustered ?? In my opinion, yes it is. Because, since we use clustered index first, our rows are sorted and so while using nonclustered index on this data file, finding adress of the record on this sorted data is really easier than finding adress of the record on unsorted data, is not it ??
