Data compression

Question

Data compression

Tara-1044200

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April 7, 2010 at 3:55 pm

#213496

Guys.. I have read that 2008 will compress data in the databases and also backup when compared to 2005. Can some one please let me know what is the exact % of data and backup files that compressess comparing it to 2005.

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Jeff Moden SSC Guru Points: 1004340 More actions · Answer 1

Tara-1044200 (4/7/2010)
Can some one please let me know what is the exact % of data and backup files that compressess comparing it to 2005.

No because, just like a ZIP file, it depends on the data.

--Jeff Moden

RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)

Garadin One Orange Chip Points: 29613 More actions · Answer 2

Most of the backups I've seen have had somewhere between 50-80% size reduction. That's just ballpark possible numbers though, as Jeff said, it depends on the Data.

The live data... I wouldn't even throw out a guess. If you have a sql 2008 developer or enterprise install to play with, you can use this script by Paul Nielsen to estimate the compression savings for your database.

Seth Phelabaum

Consistency is only a virtue if you're not a screwup. 😉

Links: How to Post Sample Data[/url] :: Running Totals[/url] :: Tally Table[/url] :: Cross Tabs/Pivots[/url] :: String Concatenation[/url]

Tara-1044200 SSCoach Points: 15951 More actions · Answer 3

I understand it depends on that data, but i would like do some comparision which may not be accurate but give me an idea of hoe much disk space i will be saving when migrating from 2005 to 2008.

need a rough number to measure how much mdf files will be compressed and .BAK files.

GregoryF SSCertifiable Points: 6296 More actions · Answer 4

The only reasonably accurate way to estimate those numbers is in your test environment. There are many variables in getting a calculation. Are you storing bits, reals, int, varchars...each compress different

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vidya_pande SSCertifiable Points: 5275 More actions · Answer 5

Regarding compressed tables/ data-

PAGE compression gives more compression ratio than ROW compression.

Page compression uses the actual logic for compression. Row compression happens only on fixed length data types.

Tara-1044200 SSCoach Points: 15951 More actions · Answer 6

Tara-1044200

SSCoach

Points: 15951

April 8, 2010 at 9:02 am

#1148368

most of our data is varchar, may be 90%

Stefan_G SSCertifiable Points: 6609 More actions · Answer 7

The only way to know how much compression you would actually get is to actually try it on your data.

Install SQL 2008 developer somewhere

Import a sample of your largest tables into the 2008 database, use sp_estimate_data_compression_savings to check the compression you would actually get.

In my environment PAGE compression compressed my data with over 70%.

/SG

Deepak Kolapkar SSC-Addicted Points: 409 More actions · Answer 8

Hi

Did the table(s) that you did compression had any XML datatype columns in it?

I am been doing some prototype where I see that compression does saves a lot of space, but only when there is no XML column.

When a table have a XML column in it as major contributor to table size, the compression does not show any significant savings in data space.

Just wanted to know you if you had any such scenario of XML columns in your tables?

Thanks