I'm currently using a system where the number of column in any given table is so great that the columns are often split into additonal tables. I know it's a wierd design but there you go. So I have to deal with tables looking like: MathResult, MathResult_2, MathResult_3, etcEach table is basically the same entity, i.e. it has the same number of rows and each row has the same key value as its peer tables. My question is that should I create a view to bring the tables together, given that a View doesn't seem to have any sort of row-size restriction? Normally I shy away from Views because I've always found them to bring performance down. Any thoughts?
I want to use VIEWS to filter records using a stored procedure to call the VIEW. Will I get a performance boost from using a VIEW, or should I just use the SQL statement that I used to create the VIEW, in my SP and forget about calling a VIEW at all?
I have a query which retrieves data from 4-5 tables. To restrict the acess directly to the tables, views have been created on all these tables. These views are just select * from the tables. Two of these 5 tables have 700 Million and 8 Million rows respectively. And all the tables are having indexes. My issue here is that my query on views take three times more then the duration it takes to retrive data directly from tables. e.g. To retrieve 1 Miliion rows, it takes just 7-10 minutes on tables but on views it takes more than 30 minutes. When I check the query plan for both the options, I can see that indexes are being picked up but still the views are very slow.
Creating indexes on views is not feasible option for me as it requires DDL changes and so much testing efforts.
I'm have a table which is filled daily by a procedure. This procedure executes for around 2 hours. Now i also want to create a clustered index view on this table.
Now during the time data is being inserted in this table, would the performance of server get hit.? Since it think it would continiously be updating this view during this duration.
Is there a way i can temporarily disconnect the view?
When working with databases containing myriad of huge tables, I am very much tempted to create categorized views on those tables in order to simplify and facilitate data query programming? Some developers I talk to say such views generally slow down query performance. Is this true? Thanks.
Over the years I've read and experienced where joining more then 5 tables can lead to performance problems. This number can vary based upon the amount of data in each table, if and how indexes are used and the complexity of the query, but 5 has always been a good rule of thumb. Unfortunately I do not know what rule to apply in regards to joing views.
A developer has experienced timeout problems periodically when opening a view in EM or when running the code which makes-up the view. I decided to look at the view and noticed it references tables and views, which reference more views, which in turn reference other views. In all the initial view references 5 tables and 8 views directly and indirectly, with some of the views containing function calls. What are your thoughts on how many views and tables are too many when it comes to joins and query performance.
OK so I have this EAV system on a server that is old enough for kindergarten. Insanely enough, this company that makes more money than any of your gods can not buy me a new box.
Before you say "redesign", I need funding allocated for that. See my first statement.
Anywho, I have this page that touches the dreaded Value table and does a clustered index seek on it. Can't search faster than that, right? Well I am getting some funding for "performance tuning". I am wondering if maybe incorporating some clustered index views involving the value table and producing a smaller clustered index for it to seek may alleviate some of this. Any thoughts?
Dear All, i've tried with indexed views, but because the view is referenceing another view, i was unable to create a clustered index on that view. so please let me know how can i improve the performance of the view.
thank you very much
Vinod Even you learn 1%, Learn it with 100% confidence.
I posted this same question couple of times in the news groups but no answers. I have a 2 tables and i am doing a union query using a view. each has 250 rows. The query takes 20 seconds to return the results. no joins or anything. the create view simply looks like this:
create view myview as select id, name from table1 union select id,name from table2
Where as if i write a stored procedure like below, it returns the rows in 4 seconds. create table #mytable ( id int, name varchar(30)) insert into #mytable (id, name) select id, name from table1 insert into #mytable (id, name) select id, name from table2 select id,name from #mytable.
I prefer doing in the view since both returns the same result. I tried running dbcc, update statistics. but no luck. Can anyone please help me in this issue.
I wonder if anyone has any hard fact based pro or contra, especially onperformance, about having views as opposed to tables when the object isbeing accessed for read only by multiple sessions/users/spids. I amparticularly concerned about the multiple instantiations of the view.Relevant thoughts on this are much appreciated.Thanks,Caveman
The code below is from a nested view, which I've read should be avoided. I've also noticed GETDATE() is used, which I believe causes GETDATE() to be executed for every record selected (correct me if I'm wrong). I'm also guessing a JOIN containing a UNION against a SELECT statement is not a good idea. What other problems do you notice?
SELECT trans.Entry_Code, trans.D_C, trans.ADP_Security_# , trans.TRID, trans.Batch_Code, trans.Last_Money, null as Shares, Settle_date as Process_Date, null as Closing_Price, trans.Dwnld_Date, trans.Acnt, null as Mktval, cast(Null as varchar(20)) as Cusip_#, ACT.dbo.account.account_key AS account_key FROM (SELECT * FROM ADPDBBOOK.dbo.YTD05B WHERE (DATEDIFF(mm, Process_Date, GETDATE()) <= 15) UNION SELECT * FROM ADPDBBOOK.dbo.YTD06B) trans INNER JOIN ACT_DATA.dbo.account ON ACT_DATA.dbo.account.account_key = RIGHT(trans.Acnt, 5) INNER JOIN tbl_Accounts_TransactionalData ON trans.Acnt = tbl_Accounts_TransactionalData.Acnt
I have come across this problem with SQL server both on 2000 and 2005. I am stating an example here.
I have two partitioned tables and a view on top of both tables as below: create table [dbo].[Table_1] ( [TableID] INTEGER PRIMARY KEY NONCLUSTERED CHECK NOT FOR REPLICATION ([TableID] BETWEEN 1 AND 999), [AnyOtherColumn] int NOT NULL , ) ON [Primary] GO
create table [dbo].[Table_2] ( [TableID] INTEGER PRIMARY KEY NONCLUSTERED CHECK NOT FOR REPLICATION ([TableID] BETWEEN 1000 AND 1999), [AnyOtherColumn] int NOT NULL , ) ON [Primary] GO create view TableView as select * from Table_1 union all select * from Table_2 GO
Note the NOT FOR REPLICATION clause on the check constraint on the TableID column.
I then ran the query execution plan for the following query on both SQL server 2000 and 2005. select * from TableView where TableID = 10
On both the versions the execution plan shows and Index seek on both the tables in the view. This means that my partitioning is not working. If I remove the primary key constraint from the TableID column, the same query on the view shows a table scan on all the underlying tables. This is even worse.
Next, create the same tables and views again, now without the NOT FOR REPLICATION clause on the check constraint as show below: create table [dbo].[Table_1] ( [TableID] INTEGER PRIMARY KEY NONCLUSTERED CHECK ([TableID] BETWEEN 1 AND 999), [AnyOtherColumn] int NOT NULL , ) ON [Primary] GO
create table [dbo].[Table_2] ( [TableID] INTEGER PRIMARY KEY NONCLUSTERED CHECK ([TableID] BETWEEN 1000 AND 1999), [AnyOtherColumn] int NOT NULL , ) ON [Primary] GO
create view TableView as select * from Table_1 union all select * from Table_2 GO
Now run the query execution plan for the same query again.
select * from TableView where TableID = 10
This time you would see that it does an index scan only on the first parititon table. This time it proves that the partitioning works.
I would like to know why does the NOT FOR REPLICATION clause in the check constraint make such a huge difference?
Fellow database developers,I would like to draw on your experience with views. I have a databasethat includes many views. Sometimes, views contains other views, andthose views in turn may contain views. In fact, I have some views inmy database that are a product of nested views of up to 6 levels deep!The reason we did this was.1. Object-oriented in nature. Makes it easy to work with them.2. Changing an underlying view (adding new fields, removing etc),automatically the higher up views inherit this new information. Thismake maintenance very easy.3. These nested views are only ever used for the reporting side of ourapplication, not for the day-to-day database use by the application.We use Crystal Reports and Crystal is smart enough (can't believe Ijust said that about Crystal) to only pull back the fields that arebeing accessed by the report. In other words, Crystal will issue aSelect field1, field2, field3 from ReportingView Where .... eventhough "ReportingView" contains a long list of fields.Problems I can see.1. Parent views generally use "Select * From childview". This meansthat we have to execute a "sp_refreshview" command against all viewswhenever child views are altered.2. Parent views return a lot of information that isn't necessarilyused.3. Makes it harder to track down exactly where the information iscoming from. You have to drill right through to the child view to seethe raw table joins etc.Does anyone have any comments on this database design? I would love tohear your opinions and tales from the trenches.Best regards,Rod.
Newbie here. I've only been using SQL for about a year now and have some minor questions about sql objects that reference other objects.
We have some views which reference other views in the joins. I will call one the primary view and the one being referenced in the joins as the secondary view.
Recently we made changes to the secondary view.
After which the primary views which referenced it would not work because of this change and had to be 'refreshed' by using drop/create scripts which essentially just dropped it and recreated the exact same view. I do not recall the exact error message that was returned other than it seemed to suggest that it could no longer see the secondary view since it had been changed. Nothing in the primary view was changed in any way, just the secondary.
Some here where I work have suggested off hand that this was a recompile of the primary view because the contents of the secondary changed.
My questions are:
1. Exactly why did this happen and is there a proper name for it when it does?
2. The same problem does not seem to occur when we have stored procedures referencing views in the joins which had just been changed. Why is that?
Thanks for any help on the matter. I greatly appreciate it.
Hello There,I'm trying to create a view that has calculations dependent oncalculations, where the problem resides is that each time I make acalculation I must create an intermediate view so I can reference aprevious calculation.for example lets say I have my_table that has columns a & b. now I wanta view that has a & b, c = a + b, and d = c + 1.this is grossly simplified, the calculations I actually use are fairlycomplex and copying / pasting them is out of the question.so what I have is my_view_a which makes column c, and my my_view_finalwhich makes column d (however, in my real application I have 5 of theseviews, a/b/c/d/e/)is there anyway I can consolidate all these views into one? I wasthinking of using a stored procedure with temp tables or somethingalong those lines.I just which I can use the aliases that I create for c in d in onestep.any insight would be greatly appreciated.
Hello Everyone,I have a very complex performance issue with our production database.Here's the scenario. We have a production webserver server and adevelopment web server. Both are running SQL Server 2000.I encounted various performance issues with the production server with aparticular query. It would take approximately 22 seconds to return 100rows, thats about 0.22 seconds per row. Note: I ran the query in singleuser mode. So I tested the query on the Development server by taking abackup (.dmp) of the database and moving it onto the dev server. I ranthe same query and found that it ran in less than a second.I took a look at the query execution plan and I found that they we'rethe exact same in both cases.Then I took a look at the various index's, and again I found nodifferences in the table indices.If both databases are identical, I'm assumeing that the issue is relatedto some external hardware issue like: disk space, memory etc. Or couldit be OS software related issues, like service packs, SQL Serverconfiguations etc.Here's what I've done to rule out some obvious hardware issues on theprod server:1. Moved all extraneous files to a secondary harddrive to free up spaceon the primary harddrive. There is 55gb's of free space on the disk.2. Applied SQL Server SP4 service packs3. Defragmented the primary harddrive4. Applied all Windows Server 2003 updatesHere is the prod servers system specs:2x Intel Xeon 2.67GHZTotal Physical Memory 2GB, Available Physical Memory 815MBWindows Server 2003 SE /w SP1Here is the dev serers system specs:2x Intel Xeon 2.80GHz2GB DDR2-SDRAMWindows Server 2003 SE /w SP1I'm not sure what else to do, the query performance is an order ofmagnitude difference and I can't explain it. To me its is a hardware oroperating system related issue.Any Ideas would help me greatly!Thanks,Brian T*** Sent via Developersdex http://www.developersdex.com ***
Hello Everyone,I have a very complex performance issue with our production database.Here's the scenario. We have a production webserver server and adevelopment web server. Both are running SQL Server 2000.I encounted various performance issues with the production server witha particular query. It would take approximately 22 seconds to return100 rows, thats about 0.22 seconds per row. Note: I ran the query insingle user mode. So I tested the query on the Development server bytaking a backup (.dmp) of the database and moving it onto the devserver. I ran the same query and found that it ran in less than asecond.I took a look at the query execution plan and I found that they we'rethe exact same in both cases.Then I took a look at the various index's, and again I found nodifferences in the table indices.If both databases are identical, I'm assumeing that the issue isrelated to some external hardware issue like: disk space, memory etc.Or could it be OS software related issues, like service packs, SQLServer configuations etc.Here's what I've done to rule out some obvious hardware issues on theprod server:1. Moved all extraneous files to a secondary harddrive to free up spaceon the primary harddrive. There is 55gb's of free space on the disk.2. Applied SQL Server SP4 service packs3. Defragmented the primary harddrive4. Applied all Windows Server 2003 updatesHere is the prod servers system specs:2x Intel Xeon 2.67GHZTotal Physical Memory 2GB, Available Physical Memory 815MBWindows Server 2003 SE /w SP1Here is the dev serers system specs:2x Intel Xeon 2.80GHz2GB DDR2-SDRAMWindows Server 2003 SE /w SP1I'm not sure what else to do, the query performance is an order ofmagnitude difference and I can't explain it. To me its is a hardware oroperating systemrelated issue.Any Ideas would help me greatly!Thanks,Brian T
Hi everyone, I have a problem like this . I have tables Coursegroupcode, which has groupname, codeI have Courses That has Coursename, its code(group code),Term, Course Number Enrollment table which has Foreign keys Term,Course NUmber , SSN I need to get a view like thisI should list all the coursecodes and people enrolled for each course code for selected terms Course Table Primary keys(TERM,COUSE Number)Enrollment Table(Foreign keys) TERM ,COURSE NUMBER, SSNplease help
Can SQL Views insert to the tables they are created from?I have a database that is not well structured. It has a lot of redundency. What I want to do is create a SQL View that brings in all the data I need and have my application use that new SQL View instead of the data tables. Then I want to be able to insert new information to a SQL View that actualy gets inserted into the tables that the SQL Viewer is created from.Can this be done?Does this make any sense?
I have a query which unions the four select statements.....
the select statements are joined with other tables and views.....
When i execute the query i get ODBC timeout error........
But the strange thing is that if i execute the view individually once and again execute the query it works fine.......and later it justs works fine....
Is there a performance hit running a sp against a view versus a base table. The view just excludes several of the records based on some criteria, and all the data I will be retreiving is included in the view. Or should I just stick my criteria in the SP to exclude the data?
I have some rather complex views to work with. Do they slow you down? Would it be better to move a view into a stored procedure? Is there any difference between these three solutions? <B>1.Using views:</b> Create view X As Select Col1, Col2, Col3 from Table1 Go
Create view Y As Select Col1, Col2, Col3 from Table2 Go
Create proc Z As Select X.Col2, X.Col3, Y.Col2, Y.Col3 From X inner join Y on X.Col1 = X.Col1 GO
<b>2.Using just a stored proc:</b> Create proc Z As Select X.Col2, X.Col3, Y.Col2, Y.Col3 from (Select Col1, Col2, Col3 from Table1) X inner join (Select Col1, Col2, Col3 from Table2) Y on X.Col1 = Y.Col1
<b>.Joining tables</b> Create proc Z As Select Table1.Col2, Table1.Col3, Table2.Col1, Table2.Col3 FromTable1 inner join Table2 on Table1.Col1 = Table2.Col1 go
My First time building "Views" in SQL...... I'm trying to figure out how to return a 1 instead of a two when I Count the number of records that return inn my view.
here's what I have;
SELECT TOP 100 PERCENT dbo.tbl_ProcTimesheet.idCalendar, dbo.tbl_ProcTimesheet.erNum, dbo.tbl_ProcTimesheet.PayDate, COUNT(dbo.tbl_ProcTimesheet.TransAmt) AS Shifts, dbo.tbl_ProcTimesheet.[Employee Number], dbo.tbl_ProcTimesheet.YCode, dbo.tbl_ProcTimesheet.XCode, dbo.tbl_ProcTimesheet.ZCode, dbo.tbl_ProcTimesheet.eeLink FROM dbo.tbl_ProcTimesheet INNER JOIN dbo.tbl_SysVarRestEeShiftPayCodes ON dbo.tbl_ProcTimesheet.Code = dbo.tbl_SysVarRestEeShiftPayCodes.PayCode INNER JOIN dbo.tbl_SysVarRestEeShiftRules ON dbo.tbl_ProcTimesheet.YCode = dbo.tbl_SysVarRestEeShiftRules.YCode AND dbo.tbl_ProcTimesheet.ZCode = dbo.tbl_SysVarRestEeShiftRules.ZCode WHERE (dbo.tbl_ProcTimesheet.Sequence <> N'0') AND (dbo.tbl_ProcTimesheet.Week < 3) GROUP BY dbo.tbl_ProcTimesheet.idCalendar, dbo.tbl_ProcTimesheet.erNum, dbo.tbl_ProcTimesheet.PayDate, dbo.tbl_ProcTimesheet.TransAmt, dbo.tbl_SysVarRestEeShiftRules.DailyHours, dbo.tbl_ProcTimesheet.[Employee Number], dbo.tbl_ProcTimesheet.XCode, dbo.tbl_ProcTimesheet.YCode, dbo.tbl_ProcTimesheet.ZCode, dbo.tbl_ProcTimesheet.eeLink, dbo.tbl_ProcTimesheet.Sequence, dbo.tbl_ProcTimesheet.Week HAVING ('IIf' > '1,1,0') AND ('if' > '1,1') AND (dbo.tbl_ProcTimesheet.erNum LIKE N'5648 ') AND (SUM(dbo.tbl_ProcTimesheet.TransAmt) >= dbo.tbl_SysVarRestEeShiftRules.DailyHours) AND (dbo.tbl_ProcTimesheet.PayDate = CONVERT(DATETIME, '2005-09-06 00:00:00', 102)) AND (COUNT(dbo.tbl_ProcTimesheet.TransAmt) > 0) ORDER BY dbo.tbl_ProcTimesheet.PayDate, dbo.tbl_ProcTimesheet.[Employee Number]
When it counts shifts, I only want to return a maximum of i, as in either you had a shoft that day, or not. I gave up trying to figure out the "IF" string in SQL, and for the life of me I can not figure this out.
Does anyone know a good site with info on how to construct an SQL View?