cpu going high (100%) after Index is created

Hi,
Any idea why CPU is going to 100% utilization as soon as i created index
(non clustered) on a table which has indexes already on the table.
before creating index the CPU is about 10 to 20% busy, after creating index
it is going to 100% consistently for about 10 minutes then i dropped index
cpu usage came down to normal
Thanks,
SUBBU.creating index is a resource intensive process, that is one of the
reason people normally find a off peak window for reindexing.
Resources varies depends on how many rows you have of the table and how
many columns you include in the non-clustered index and what are they
(data type).
If you can provide clustered index columns (if any), non-clustered
index columns (the one you intended to put), we can find out more.
Mel|||Hi
I understand creating CPU is resource intensive. CPU is going high after
index is created not while being created.
As of now the table has 98000 rows, aprox 800 pages, 1 clustered composite,
6 non clustered composite.
Data is very static in nature
Thanks,
Subbu.
"MSLam" <MelodySLam@.googlemail.com> wrote in message
news:1144960243.264788.102540@.z34g2000cwc.googlegroups.com...
> creating index is a resource intensive process, that is one of the
> reason people normally find a off peak window for reindexing.
> Resources varies depends on how many rows you have of the table and how
> many columns you include in the non-clustered index and what are they
> (data type).
> If you can provide clustered index columns (if any), non-clustered
> index columns (the one you intended to put), we can find out more.
> Mel
>|||You might just have gotten a bad plan. I would try it again.
Andrew J. Kelly SQL MVP
"subbu" <subbaiahd@.hotmail.com> wrote in message
news:%235Pf63zXGHA.3516@.TK2MSFTNGP03.phx.gbl...
> Hi
> I understand creating CPU is resource intensive. CPU is going high after
> index is created not while being created.
> As of now the table has 98000 rows, aprox 800 pages, 1 clustered
> composite,
> 6 non clustered composite.
> Data is very static in nature
> Thanks,
> Subbu.
>
> "MSLam" <MelodySLam@.googlemail.com> wrote in message
> news:1144960243.264788.102540@.z34g2000cwc.googlegroups.com...
>|||Sorry misunderstood your question in the first place.
One thing to bear in mind that putting index is NOT costless. In fact,
having more than enough indexes can cause problem, particularly if you
enviornment is OLTP. It will help for SELECT but not
UPDATE/INSERT/DELETE (as the index will need to be updated at the same
time).
My rule is always have a one good clustered index and 1-3 non-clustered
indexes should do the job.
Mel|||(BI = Before Index Created
AI = After Index created)
The query for which i have created index is executing faster AI. the query
which was going for index scan (BI) now going for index seek (AI), and
total execution time came down from 9 sec to 1 sec. But CPU is going to
100%, I am guessing does the new index made all other queries to run slow. I
dont worry about INSERT/DELETE/UPDATE, I need to tune SELECT stmts only
(the data is very static). Is SQL Server not intelligent to ignore indexes
that are not useful in plan preparation. If i create a new index it looks
like other queries which joins this table are going to wrong execution
plans. Please help.
Thanks,
Subbu
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:OltKJu1XGHA.4652@.TK2MSFTNGP04.phx.gbl...
> You might just have gotten a bad plan. I would try it again.
> --
> Andrew J. Kelly SQL MVP
>
> "subbu" <subbaiahd@.hotmail.com> wrote in message
> news:%235Pf63zXGHA.3516@.TK2MSFTNGP03.phx.gbl...
>|||How many CPU's do you have? It's possible that parallelism is being used
suboptimally. I'd use the Profiler to find which queries are being
affected. For those, you may want to use OPTION (MAXDOP 1).
Tom
----
Thomas A. Moreau, BSc, PhD, MCSE, MCDBA
SQL Server MVP
Toronto, ON Canada
.
"subbu" <subbaiahd@.hotmail.com> wrote in message
news:uLyApr8XGHA.4920@.TK2MSFTNGP02.phx.gbl...
(BI = Before Index Created
AI = After Index created)
The query for which i have created index is executing faster AI. the query
which was going for index scan (BI) now going for index seek (AI), and
total execution time came down from 9 sec to 1 sec. But CPU is going to
100%, I am guessing does the new index made all other queries to run slow. I
dont worry about INSERT/DELETE/UPDATE, I need to tune SELECT stmts only
(the data is very static). Is SQL Server not intelligent to ignore indexes
that are not useful in plan preparation. If i create a new index it looks
like other queries which joins this table are going to wrong execution
plans. Please help.
Thanks,
Subbu
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:OltKJu1XGHA.4652@.TK2MSFTNGP04.phx.gbl...
> You might just have gotten a bad plan. I would try it again.
> --
> Andrew J. Kelly SQL MVP
>
> "subbu" <subbaiahd@.hotmail.com> wrote in message
> news:%235Pf63zXGHA.3516@.TK2MSFTNGP03.phx.gbl...
>|||Thanks for the idea, i have one cpu.
"Tom Moreau" <tom@.dont.spam.me.cips.ca> wrote in message
news:%23H$8I$8XGHA.128@.TK2MSFTNGP05.phx.gbl...
> How many CPU's do you have? It's possible that parallelism is being used
> suboptimally. I'd use the Profiler to find which queries are being
> affected. For those, you may want to use OPTION (MAXDOP 1).
> --
> Tom
> ----
> Thomas A. Moreau, BSc, PhD, MCSE, MCDBA
> SQL Server MVP
> Toronto, ON Canada
> .
> "subbu" <subbaiahd@.hotmail.com> wrote in message
> news:uLyApr8XGHA.4920@.TK2MSFTNGP02.phx.gbl...
> (BI = Before Index Created
> AI = After Index created)
>
> The query for which i have created index is executing faster AI. the query
> which was going for index scan (BI) now going for index seek (AI), and
> total execution time came down from 9 sec to 1 sec. But CPU is going to
> 100%, I am guessing does the new index made all other queries to run slow.
I
> dont worry about INSERT/DELETE/UPDATE, I need to tune SELECT stmts only
> (the data is very static). Is SQL Server not intelligent to ignore indexes
> that are not useful in plan preparation. If i create a new index it looks
> like other queries which joins this table are going to wrong execution
> plans. Please help.
> Thanks,
> Subbu
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:OltKJu1XGHA.4652@.TK2MSFTNGP04.phx.gbl...
after[vbcol=seagreen]
how[vbcol=seagreen]
>|||Well, it's not parallelism, then. I'd still use the profiler to figure out
where the bones are buried.
Tom
----
Thomas A. Moreau, BSc, PhD, MCSE, MCDBA
SQL Server MVP
Toronto, ON Canada
.
"subbu" <subbaiahd@.hotmail.com> wrote in message
news:eoh%23Ks9XGHA.4248@.TK2MSFTNGP05.phx.gbl...
Thanks for the idea, i have one cpu.
"Tom Moreau" <tom@.dont.spam.me.cips.ca> wrote in message
news:%23H$8I$8XGHA.128@.TK2MSFTNGP05.phx.gbl...
> How many CPU's do you have? It's possible that parallelism is being used
> suboptimally. I'd use the Profiler to find which queries are being
> affected. For those, you may want to use OPTION (MAXDOP 1).
> --
> Tom
> ----
> Thomas A. Moreau, BSc, PhD, MCSE, MCDBA
> SQL Server MVP
> Toronto, ON Canada
> .
> "subbu" <subbaiahd@.hotmail.com> wrote in message
> news:uLyApr8XGHA.4920@.TK2MSFTNGP02.phx.gbl...
> (BI = Before Index Created
> AI = After Index created)
>
> The query for which i have created index is executing faster AI. the query
> which was going for index scan (BI) now going for index seek (AI), and
> total execution time came down from 9 sec to 1 sec. But CPU is going to
> 100%, I am guessing does the new index made all other queries to run slow.
I
> dont worry about INSERT/DELETE/UPDATE, I need to tune SELECT stmts only
> (the data is very static). Is SQL Server not intelligent to ignore indexes
> that are not useful in plan preparation. If i create a new index it looks
> like other queries which joins this table are going to wrong execution
> plans. Please help.
> Thanks,
> Subbu
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:OltKJu1XGHA.4652@.TK2MSFTNGP04.phx.gbl...
after[vbcol=seagreen]
how[vbcol=seagreen]
>|||If you query originally took 9 seconds and now takes 1 then you must be
returning a lot of rows. The CPU going to 100% is probably just a sign that
it is now able to process more efficiently and thus faster. If no one lese
is on the server and you issue the query and the CPU spikes to 100% for 1
second and then drops to 0 everything is OK.
Andrew J. Kelly SQL MVP
"subbu" <subbaiahd@.hotmail.com> wrote in message
news:uLyApr8XGHA.4920@.TK2MSFTNGP02.phx.gbl...
> (BI = Before Index Created
> AI = After Index created)
>
> The query for which i have created index is executing faster AI. the query
> which was going for index scan (BI) now going for index seek (AI), and
> total execution time came down from 9 sec to 1 sec. But CPU is going to
> 100%, I am guessing does the new index made all other queries to run slow.
> I
> dont worry about INSERT/DELETE/UPDATE, I need to tune SELECT stmts only
> (the data is very static). Is SQL Server not intelligent to ignore indexes
> that are not useful in plan preparation. If i create a new index it looks
> like other queries which joins this table are going to wrong execution
> plans. Please help.
> Thanks,
> Subbu
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:OltKJu1XGHA.4652@.TK2MSFTNGP04.phx.gbl...
>