fragmentation question

Hi friends,
Is it possible that over any period of time page split occur thus increasing
logical fragmentation, but Avg. Page density whis is shown in DBCC
SHOWCONTIG remains relatively at the same level ? In another words, what is
exactly relationship between those two?
Thanks in advance
AlexAlex
Read this article
http://www.sql-server-performance.com/rd_index_fragmentation.asp
"Alex" <me@.isp.net> wrote in message news:9Q9If.17$Nr5.1@.clgrps13...
> Hi friends,
> Is it possible that over any period of time page split occur thus
> increasing logical fragmentation, but Avg. Page density whis is shown in
> DBCC SHOWCONTIG remains relatively at the same level ? In another words,
> what is exactly relationship between those two?
> Thanks in advance
> Alex
>|||Yes. Imagine you start with 75% full pages. As a page becomes full, it is split onto two half full
pages. So, assuming the data is spread evenly across the pages, you will end up with the middle of
100% and 50% full pages.
--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://www.solidqualitylearning.com/
Blog: http://solidqualitylearning.com/blogs/tibor/
"Alex" <me@.isp.net> wrote in message news:9Q9If.17$Nr5.1@.clgrps13...
> Hi friends,
> Is it possible that over any period of time page split occur thus increasing logical
> fragmentation, but Avg. Page density whis is shown in DBCC SHOWCONTIG remains relatively at the
> same level ? In another words, what is exactly relationship between those two?
> Thanks in advance
> Alex
>|||Thanks Uri
"Uri Dimant" <urid@.iscar.co.il> wrote in message
news:%23GZtGOTMGHA.1536@.TK2MSFTNGP11.phx.gbl...
> Alex
> Read this article
> http://www.sql-server-performance.com/rd_index_fragmentation.asp
>
>
> "Alex" <me@.isp.net> wrote in message news:9Q9If.17$Nr5.1@.clgrps13...
>> Hi friends,
>> Is it possible that over any period of time page split occur thus
>> increasing logical fragmentation, but Avg. Page density whis is shown in
>> DBCC SHOWCONTIG remains relatively at the same level ? In another words,
>> what is exactly relationship between those two?
>> Thanks in advance
>> Alex
>>
>|||That means that table can have Avg Page Density(or internal fragmentation)
within desirable range (say 88-92) being at the same time somewhat heavily
defragmented (so called external fragmentattion in terms of the article Uri
refered) when logical fragmentation is way more than 10, right?
"Tibor Karaszi" <tibor_please.no.email_karaszi@.hotmail.nomail.com> wrote in
message news:uTYgJVUMGHA.3960@.TK2MSFTNGP09.phx.gbl...
> Yes. Imagine you start with 75% full pages. As a page becomes full, it is
> split onto two half full pages. So, assuming the data is spread evenly
> across the pages, you will end up with the middle of 100% and 50% full
> pages.
> --
> Tibor Karaszi, SQL Server MVP
> http://www.karaszi.com/sqlserver/default.asp
> http://www.solidqualitylearning.com/
> Blog: http://solidqualitylearning.com/blogs/tibor/
>
> "Alex" <me@.isp.net> wrote in message news:9Q9If.17$Nr5.1@.clgrps13...
>> Hi friends,
>> Is it possible that over any period of time page split occur thus
>> increasing logical fragmentation, but Avg. Page density whis is shown in
>> DBCC SHOWCONTIG remains relatively at the same level ? In another words,
>> what is exactly relationship between those two?
>> Thanks in advance
>> Alex
>>
>|||Yes. "Internal fragmentation" (how full your pages are) basically has no relationship with external
fragmentation.
--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://www.solidqualitylearning.com/
Blog: http://solidqualitylearning.com/blogs/tibor/
"Alex" <me@.isp.net> wrote in message news:aSoIf.1213$n67.425@.edtnps89...
> That means that table can have Avg Page Density(or internal fragmentation) within desirable range
> (say 88-92) being at the same time somewhat heavily defragmented (so called external
> fragmentattion in terms of the article Uri refered) when logical fragmentation is way more than
> 10, right?
>
> "Tibor Karaszi" <tibor_please.no.email_karaszi@.hotmail.nomail.com> wrote in message
> news:uTYgJVUMGHA.3960@.TK2MSFTNGP09.phx.gbl...
>> Yes. Imagine you start with 75% full pages. As a page becomes full, it is split onto two half
>> full pages. So, assuming the data is spread evenly across the pages, you will end up with the
>> middle of 100% and 50% full pages.
>> --
>> Tibor Karaszi, SQL Server MVP
>> http://www.karaszi.com/sqlserver/default.asp
>> http://www.solidqualitylearning.com/
>> Blog: http://solidqualitylearning.com/blogs/tibor/
>>
>> "Alex" <me@.isp.net> wrote in message news:9Q9If.17$Nr5.1@.clgrps13...
>> Hi friends,
>> Is it possible that over any period of time page split occur thus increasing logical
>> fragmentation, but Avg. Page density whis is shown in DBCC SHOWCONTIG remains relatively at the
>> same level ? In another words, what is exactly relationship between those two?
>> Thanks in advance
>> Alex
>>
>|||thanks you guys for clarification, - you confirmed my thoughts.
"Tibor Karaszi" <tibor_please.no.email_karaszi@.hotmail.nomail.com> wrote in
message news:OUBlLCZMGHA.1028@.TK2MSFTNGP11.phx.gbl...
> Yes. "Internal fragmentation" (how full your pages are) basically has no
> relationship with external fragmentation.
> --
> Tibor Karaszi, SQL Server MVP
> http://www.karaszi.com/sqlserver/default.asp
> http://www.solidqualitylearning.com/
> Blog: http://solidqualitylearning.com/blogs/tibor/
>
> "Alex" <me@.isp.net> wrote in message news:aSoIf.1213$n67.425@.edtnps89...
>> That means that table can have Avg Page Density(or internal
>> fragmentation) within desirable range (say 88-92) being at the same time
>> somewhat heavily defragmented (so called external fragmentattion in terms
>> of the article Uri refered) when logical fragmentation is way more than
>> 10, right?
>>
>> "Tibor Karaszi" <tibor_please.no.email_karaszi@.hotmail.nomail.com> wrote
>> in message news:uTYgJVUMGHA.3960@.TK2MSFTNGP09.phx.gbl...
>> Yes. Imagine you start with 75% full pages. As a page becomes full, it
>> is split onto two half full pages. So, assuming the data is spread
>> evenly across the pages, you will end up with the middle of 100% and 50%
>> full pages.
>> --
>> Tibor Karaszi, SQL Server MVP
>> http://www.karaszi.com/sqlserver/default.asp
>> http://www.solidqualitylearning.com/
>> Blog: http://solidqualitylearning.com/blogs/tibor/
>>
>> "Alex" <me@.isp.net> wrote in message news:9Q9If.17$Nr5.1@.clgrps13...
>> Hi friends,
>> Is it possible that over any period of time page split occur thus
>> increasing logical fragmentation, but Avg. Page density whis is shown
>> in DBCC SHOWCONTIG remains relatively at the same level ? In another
>> words, what is exactly relationship between those two?
>> Thanks in advance
>> Alex
>>
>>
>