0
votes
1answer
130 views

How can I speed up this query on table with 65 million records

select hash_id, hash_value, substring(T.cri, 1, 7), substring(T.cri, 9, D2.Pos-9), substring(T.cri, D2.Pos + 1, D3.Pos - D2.Pos - 1), ...
4
votes
1answer
65 views

Drastic performance difference in View Dependencies between SQL Server 2005 and 2008 R2

Background I am a fledgling DBA who was hired in the middle of a migration from SQL Server 2005 x64 to 2008 R2 x64. We also migrated from a local server to a colo virtual server, and moved some of ...
3
votes
1answer
113 views

Most efficient queries on flags in TSQL: bit field or table join?

Looking for the most efficient database structure for selecting rows from a large table based on one or more true/false values. For example, whether or not a user has opted in to marketing ...
1
vote
1answer
98 views

Slow running query with inner SELECT in where clause

I have a query that looks like the following: USE DATABASE3; GO SELECT t1.COL1 AS COLUMN1, t2.COL2 AS COLUMN2, t1.COL3, t1.COL4 AS COLUMN4, t1.COL5 AS COLUMN5, ...
2
votes
1answer
98 views

T-SQL Query runs quickly on local PC, but slow on SQL Server?

I have a query with a few joins and a couple of basic SUM(...) statements, and no parameters. It's been running without issue for months - but has suddenly started running very slowly on the server ...
1
vote
1answer
225 views

SQL Server performance for tables having large number of columns [closed]

I have a requirement where I need to create a table with about 600 columns. Out of 600 columns about 200 columns will be XML columns. Other column will be of other datatypes such as int, varchar, ...
15
votes
3answers
592 views

difference in execution plans on UAT and PROD server

I want to understand why there would be such a huge difference in execution of the same query on UAT (runs in 3 sec) vs PROD (run in 23 secs). Both UAT and PROD are having exactly data and indexes. ...
0
votes
2answers
88 views

Can I improve this query?

SELECT * FROM SameLogTable WHERE ID_Table IN (SELECT ID_Table-1 FROM SameLogTable WHERE <SameCondition>) OR ID_Table IN (SELECT ID_Table ...
1
vote
1answer
481 views

Some queries are very slow after index rebuild

After finding out almost all databases on my SQL Server had fragmentation over 40%, I decided to do an index rebuild on all tables using a fill factor of 80. After rebuilding all indexes, some ...
1
vote
0answers
136 views

Sql Execution Plan - Hash Match

I'm currently working on a Sql Query that's having performance issues. I ran the execution plan and saw the Hash Match has 50% cost and also, doing a index scan. I'm starting to learning about the ...
9
votes
2answers
1k views

LIKE uses index, CHARINDEX does not?

This question is related to my old question. The below query was taking 10 to 15 seconds to execute: SELECT [customer].[Customer name],[customer].[Sl_No],[customer].[Id] FROM [company].dbo.[customer] ...
1
vote
1answer
561 views

Query taking non-consistent time to execute [closed]

I have a query which takes large time to execute sometimes.When i checked the speed it was taking 15 seconds.But actually it should run faster than that.When i again checked the query it again ...
-1
votes
1answer
104 views

Query performance in SQL Server [closed]

What factors should I check when I compare the performance of a query? I saw many articles stating about IO cost, subtree cost (by using Execution plans), statistics such as CPU time, elapsed time ...
-1
votes
2answers
915 views

Query to search for a substring in xml

I use below query to search for a substring in whole xml(including node name and node value) SELECT * FROM tablename WHERE ( Charindex('abc',CAST([xmlcolumn] AS VARCHAR(MAX)))>0 ) I want an ...
-1
votes
4answers
115 views

Dropping and recreating indexes [closed]

I most often come in a situation where the users move there database from one server to another and immediately after they move they face performance problems(slowness). I somehow manage to rebuild ...
2
votes
0answers
187 views

Simple Select * on SQL Server 2008 R2 table of 1812 rows is taking 3 minutes to load

A query on a table of 1812 rows is taking over 3 minutes to execute. Is there a reason this should be happening? If I execute a SELECT * statement on any other table the results pop back ...
3
votes
1answer
310 views

Query Performance Issue

I have this below query which is behaving bit weird . well Weird in the sense that I couldn't find complete explanation for this. Version : Sql Server 2008 R2 Enterprise No fragmentation . ...
4
votes
1answer
140 views

Same Query takes 0 seconds on Server A, 7.5 minutes on Server B (same db/hardware/config)

I have a query (sql below) that is nearly instantaneous on 1 server, but takes 7.5 minutes on another virtually (key point) identical server. The estimated query execution plans have one obvious ...
3
votes
1answer
121 views

Why does SqlSentry Plan Explorer not give the duration of my queries?

I have a large nasty stored procedure in a 13gig database that takes 45 minutes to run when I include the actual execution plan. I save the query plan from SSMS and open in up in SQL Sentry Plan ...
9
votes
1answer
514 views

query optimization: time intervals

In the main, I've got two kinds of time intervals: presence time and absence time absence time can be of different types (eg breaks, absences, special day and so on) and time intervals may overlap ...
11
votes
3answers
711 views

Improve performance of query using IN()

I have the following SQL query: SELECT Event.ID, Event.IATA, Device.Name, EventType.Description, Event.Data1, Event.Data2 Event.PLCTimeStamp, Event.EventTypeID FROM Event INNER JOIN ...
3
votes
2answers
224 views

Sudden Query Performance Degradation On A Linked Server

I have an application that uses a view on a SQL Server 2008 R2 instance. This view actually queries a linked server (SQL Server 2008) that has replicated data from our main ERP database. Yesterday, we ...
2
votes
1answer
115 views

Where to place non clustered index

Execution plan clearly showing that one of my table used in query is useing Clustered Index Scan. From this node, how can i guess that which columns should be part of my non clustered index key and ...
4
votes
2answers
416 views

Poor performance after changing SQL Server 2008 R2 database

Need some tips on what I can do to track down this problem. My client has a modest sized SQL Server 2008 R2 database (approx 6 gigs in size). Last week I modified the database to add new a single new ...
11
votes
1answer
277 views

How does SQL Server know predicates are correlated?

While diagnosing SQL Server 2008 R2 queries with poor cardinality estimation (despite simple indexing, up-to-date statistics, etc.) and hence poor query plans, I found a perhaps-related KB article: ...
3
votes
2answers
219 views

How do I count rows with two properties in one index scan in SQL?

I have a table Units where I have rows ItemId, ItemCreationDate, ItemUnitsCount. ItemId is a primary key and I have a clustered index over it. I need to output the following: for each day I need to ...
1
vote
3answers
356 views

Checking if the query is made async or sync on SQL Server 2008 R2

I have tried to make async calls to my SQL Server instance as you may see on my SO post: ASP.NET MVC 4 asyncronous database call: never returns the HTTP response I did a benchmarking and the sync ...