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 Can large size of MDF files decrease performance?

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lebedev
Posting Yak Master

126 Posts

Posted - 2010-01-07 : 18:52:59
We are running SQL Server 2005 on Windows Server 2003.

Our MDF file has grown to 5GB. We are having some performance problems, but I don't know if they are directly related to the file size itself. Can the sheer size of the MDF file decrease performance? Is it common to have multi-terrabyte MDF files?

The database file group has only one MDF file. In general, is there a guideline when more files should be added to the database file group?

Thanks,

Alec

tkizer
Almighty SQL Goddess

38200 Posts

Posted - 2010-01-07 : 19:02:58
A 5GB file is tiny and would not impact performance. If it were 1TB then it'd be a different story.


Tara Kizer
Microsoft MVP for Windows Server System - SQL Server
http://weblogs.sqlteam.com/tarad/

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"Let's begin with the premise that everything you've done up until this point is wrong."
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lebedev
Posting Yak Master

126 Posts

Posted - 2010-01-08 : 12:07:05
Thank you for the great response.
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tkizer
Almighty SQL Goddess

38200 Posts

Posted - 2010-01-08 : 12:47:20
You're welcome.

Tara Kizer
Microsoft MVP for Windows Server System - SQL Server
http://weblogs.sqlteam.com/tarad/

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russell
Pyro-ma-ni-yak

5072 Posts

Posted - 2010-01-08 : 14:53:31
by the way, i'll bet your performance issues are due to bad or missing indexes. examine the execution plan for queries that are performing poorly, with an eye out for table scans and index scans.
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jackv
Master Smack Fu Yak Hacker

2179 Posts

Posted - 2010-01-08 : 16:13:34
As well the suggestion above , consider the nature of the data , and consider coming up with an appropriate maintenance plan -

Jack Vamvas
--------------------
http://www.ITjobfeed.com
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Peter99
Constraint Violating Yak Guru

498 Posts

Posted - 2010-01-08 : 17:16:56
5GB is not a big database, we have 80GB in one data file. Try to update statistics or rebuild indexes.
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jackv
Master Smack Fu Yak Hacker

2179 Posts

Posted - 2010-01-09 : 07:05:12
Just to clarify , what is the main advantage of breaking a large MDF down into smaller data files?

Jack Vamvas
--------------------
http://www.ITjobfeed.com
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lebedev
Posting Yak Master

126 Posts

Posted - 2010-01-10 : 18:28:07
Just to follow-up on my original post. We analyzed query plans and found that performance problems were linked to obsolete query plans.
We access the database using JDBC PreparedStatements which create stored procedures and reuse them over and over without recompiling the execution plans. So, over time execution plans get out of date causing performance problems.

We found other performance problems but all of them were unrelated to the size of the MDF file.

However, the 60GB guideline that Tara suggested will still be very useful for us in the near future.
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SCHEMA
Posting Yak Master

192 Posts

Posted - 2012-11-14 : 21:24:49
Hi Tara,

I have large(200 GB) with 1 mdf file.? will i have any issue? Is there any microsoft article explaining the consequences?
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tkizer
Almighty SQL Goddess

38200 Posts

Posted - 2012-11-15 : 13:50:24
quote:
Originally posted by SCHEMA

Hi Tara,

I have large(200 GB) with 1 mdf file.? will i have any issue? Is there any microsoft article explaining the consequences?



I've removed my posts regarding the topic you are referring to as it was bad advice.

Tara Kizer
Microsoft MVP for Windows Server System - SQL Server
http://weblogs.sqlteam.com/tarad/

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TG
Master Smack Fu Yak Hacker

6065 Posts

Posted - 2012-11-15 : 14:12:06
>>I've removed my posts regarding the topic you are referring to as it was bad advice.
Man, if we have to delete our posts where we gave bad advice I've got a lot of work to do!

Be One with the Optimizer
TG
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sodeep
Master Smack Fu Yak Hacker

7174 Posts

Posted - 2012-11-15 : 15:59:10
TG
I will also have to see it.
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