performance issue in a select query from a single table

Posted by daedlus on Stack Overflow See other posts from Stack Overflow or by daedlus
Published on 2010-03-16T07:14:13Z Indexed on 2010/03/16 7:16 UTC
Read the original article Hit count: 431

Filed under:

sql

|

select

|

sybase

|

query-optimization

Hi ,

I have a table as below

dbo.UserLogs

-------------------------------------
Id | UserId |Date | Name| P1 | Dirty
-------------------------------------

There can be several records per userId[even in millions]

I have clustered index on Date column and query this table very frequently in time ranges. The column 'Dirty' is non-nullable and can take either 0 or 1 only so I have no indexes on 'Dirty'

I have several millions of records in this table and in one particular case in my application i need to query this table to get all UserId that have at least one record that is marked dirty.

I tried this query - select distinct(UserId) from UserLogs where Dirty=1

I have 10 million records in total and this takes like 10min to run and i want this to run much faster than this.

[i am able to query this table on date column in less than a minute.]

Any comments/suggestion are welcome.

my env 64bit,sybase15.0.3,Linux

© Stack Overflow or respective owner

Related posts about sql

SQL SERVER – Concat Strings in SQL Server using T-SQL – SQL in Sixty Seconds #035 – Video

as seen on SQL Authority - Search for 'SQL Authority'
Concatenating string is one of the most common tasks in SQL Server and every developer has to come across it. We have to concat the string when we have to see the display full name of the person by first name and last name. In this video we will see various methods to concatenate the strings. SQL… >>> More
SQL SERVER – Concat Function in SQL Server – SQL Concatenation

as seen on SQL Authority - Search for 'SQL Authority'
Earlier this week, I was delivering Advanced BI training on the subject of “SQL Server 2008 R2″. I had great time delivering the session. During the session, we talked about SQL Server 2010 Denali. Suddenly one of the attendees suggested his displeasure for the product. He said, even though… >>> More
Error with SQL Server Setup 2012 on Windows 2012

as seen on Server Fault - Search for 'Server Fault'
I am trying to install SQL Server on Windows 2012. I was able to finally get the wizard up and running after making some changes on the server, but now it fails no matter what I do with the following error: TITLE: SQL Server Setup failure. SQL Server Setup has encountered the following error: … >>> More
How can I detect which version of SQL (eg SQL 2008 or SQL Azure)

as seen on Stack Overflow - Search for 'Stack Overflow'
I need to detect which version of SQL I am dealing with to perorm various tasks, I need specifically detect if I am on SQL 2008 or SQL Azure. How can I do this with detection code written in SQL? >>> More
Nested SQL Select statement fails on SQL Server 2000, ok on SQL Server 2005

as seen on Stack Overflow - Search for 'Stack Overflow'
Here is the query: INSERT INTO @TempTable SELECT UserID, Name, Address1 = (SELECT TOP 1 [Address] FROM (SELECT TOP 1 [Address] FROM [UserAddress] ua INNER JOIN UserAddressOrder uo ON ua.UserID = uo.UserID WHERE ua.UserID = u.UserID ORDER BY uo.AddressOrder ASC) q ORDER BY AddressOrder… >>> More

Related posts about select

HTML muliple select should look like HTML select

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi I am trying to use a HTML select box with 'multiple' select options and size to 1 as below ` <SELECT NAME="toppings" MULTIPLE SIZE=5> <OPTION VALUE="mushrooms">mushrooms <OPTION VALUE="greenpeppers">green peppers </SELECT> When the size is set to 1 small scrollbar appears… >>> More
MySQL Query Select using sub-select takes too long

as seen on Stack Overflow - Search for 'Stack Overflow'
I noticed something strange while executing a select from 2 tables: SELECT * FROM table_1 WHERE id IN ( SELECT id_element FROM table_2 WHERE column_2=3103); This query took approximatively 242 seconds. But when I executed the subquery SELECT id_element FROM table_2 WHERE column_2=3103 it… >>> More
SQL SERVER- IF EXISTS(Select null from table) vs IF EXISTS(Select 1 from table)

as seen on SQL Authority - Search for 'SQL Authority'
Few days ago I wrote article about SQL SERVER – Stored Procedure Optimization Tips – Best Practices. I received lots of comments on particular blog article. In fact, almost all the comments are very interesting. If you have not read all the comments, I strongly suggest to read them. Click here to… >>> More
Nesting Linq-to-Objects query within Linq-to-Entities query –what is happening under the covers?

as seen on Programmers - Search for 'Programmers'
var numbers = new int[] { 1, 2, 3, 4, 5 }; var contacts = from c in context.Contacts where c.ContactID == numbers.Max() | c.ContactID == numbers.FirstOrDefault() select c; foreach (var item in contacts) Console.WriteLine(item.ContactID); Linq-to-Entities… >>> More
Play Framework: Error getting sequence nextval using H2 in-memory database

as seen on Stack Overflow - Search for 'Stack Overflow'
As the title suggests, I get an error running Play 2.0.1 Tests using a FakeApplication w/ H2 in memory. I set up a basic unit test: public class ModelTest { @Test public void checkThatIndustriesExist() { running(fakeApplication(inMemoryDatabase()), new Runnable() { public… >>> More