hey guys, i need your help please.
here is the scenario:
1. I need to return a data back to client (result set varies 20-10,000)
2. I only want to show 20 records at a time
3. To get info i need to display i need to join 10 tables
When there are small #s of records it works but when i get over 8000 then it becomes a problem:
1. The first version was:
Get all data using big query and return everything back to client and display only 20 at a time (not very proficient).
Takes around 15 seconds to view 20 records.
2. Inspired by 4GuysFromRolla (http://www.4guysfromrolla.com/webtech/062899-1.shtml)
Use Stored Procedure w/ server side paging logic to get 20 records at the time. I had to pass every filter parameter and stuff. SP had to sort resultset and return only 20 records i need to display.
Takes around 5 seconds to view 20 records.
I still think it's slow, i know this is a very broad question but is there any other way to do it, logically?
Any help is appreciated.
Wojo.You coud try running a few instances of the search in anticipation of the Next/Prev scenario.
While users are reading 20 in their window the application is downloading a further 20 behind the scenes asynchronously. I couldn't give an example. At least they wouldn't be aware of the 5 seconds if it took longer to read 20.
The only other example I have is for Delphi, sorry.|||Well...you need to order by something...and you need to know what page your on...
How about..
USE Northwind
GO
DECLARE @.Page int, @.sql varchar(8000)
SELECT @.Page = 2
SELECT @.sql = 'SELECT * FROM (SELECT TOP 20 * FROM (SELECT TOP '
+ CONVERT(varchar(10),@.Page * 20)
+ ' * FROM Orders ORDER by OrderId) AS A '
+ ' ORDER By OrderID Desc) AS B '
+ ' ORDER BY OrderId'
EXEC(@.sql)|||Thanks guys,
Brett, how does this work?|||To see it work...go to QA...cut and paste the code and execute it...
What it does roughly is that if you want page x, the inner query will select the TOP x * 20 rows (last 20 will be page x...
Then order by a key descending to get the last 20 rows..the reorder those by the key, so page 20 will be in the correct order to be displayed...
test it, let me know if it works for you...
Oh, and btw, this will only transmit the 20 rows across..you don't want to be moving large chunks for no reason...especially since data is fluid and may change at any time...|||Hmm,
What if i want to sort by other columns, plus my IDs aren't sequential :(|||You have to order by something...
The order of data in a database is meaningless....
And yes can can order by more than 1 thing...
And it doesn't have to be an int...
Look at a phonebook...they don't order by phone number...|||Thanks Brett,
it looks like it works preety well, i'm getting 1-2 seconds on couple of first pages!
One last question: is there any way to get total number of records from the inner query? and i would rather not requery this, any way to get the count while doing what we are doing?
thanks|||What's the total row count?
Did you try it for the last page yet?
And...
One last question: is there any way to get total number of records from the inner query? and i would rather not requery this, any way to get the count while doing what we are doing?
Why does this matter to you? Remembering the page number should be more important...no?
And cool site btw...do you sell just parts or whole systems...where are you based out of?|||The row count was ~9k
I did and it took 6-7 seconds, which is not that bad considering almost nobody looks at last pages :)
It matters to me because i'm displaying total number of records and i need this number to drive my paging logic (ex. page 1 out of 12)
Re: my site, its just my personal project, this question is for work :) and no i actually don't sell anything in there, i wrote this site to allow people to sell buy hardware for no charge...
thanks again for all your help man!|||What are you SELECTING, and what's the ORDER BY on?
Are they all indexed?
I don't like 6/7 seconds....|||i will look into indexes later, i would like to get this running first, so i need total count of records...|||Wouldn't that just be @.Pages*20?|||lol, i need to know what @.PAGES is don't i?
i don't think i made myself clear, i want to know the total number of records i'm gonna page myself though, ex:
Found 100 records, you are on page number 1 out of 5 (since there is 20 recs per page)
thanks.|||"i will look into indexes later"
If you are concerned about performance NOW, then you need to look into indexes NOW. I wondered what kind of indexes you had when I read that it started getting slow at 8000 records. 8000 records is peanuts.
Doing a select count(*) to get the rowcount should not be too expensive. Another method is to select the rowcount from the sysindexes table.|||I should have mentined before but I do this instinctivly, you may already be doing it.
When you join yuor tables dont use * and avoid large text fields. can be quite a surprise how long they take.
Try a skeleton version of the query that just selects and joins the keys. Then work up to include fields you need.
Sorry if you are allready doing that. And nice site you have there.
