Fillfactor

I have a very simple insert statement into a table containing about a
million rows.
It runs a fraction of a second for about 1000 times and then takes about 5
seconds, and then again fraction of a second for about 1000 inserts. There
are 3 indexes on the table with fillfactor 70.
Am i right by guessing that at the time when insert takes 5 seconds the page
splits? Should i decrese fillfactor to 50? Or could it be something else?
Thanks.Perhaps there are other possible sources, but it would more likely be your
log files or data files growing. I suppose the quick and dirty check is to
simply monitor both files before and after to see if growth occured.
Autogrowth is evil in my mind.
A single page split is taking a 8K allocated space and splitting it in two
locations. While you don't want this to happen a ton, this is not a task
that would take 5 full seconds, or at least the stall would not be after
record 997 was inserted. I suppose if the records you are inserting are all
being inserted into the SAME part(page) of the index, this could be
problematic.
If the index is related to your performance issues, you could remove the
index prior to the insert, insert, and then rebuild the indexes? This is an
expensive operation too though.
Mark
"Michael Kansky" <mike@.zazasoftware.com> wrote in message
news:%23zHWWj$mIHA.5704@.TK2MSFTNGP05.phx.gbl...
>I have a very simple insert statement into a table containing about a
>million rows.
> It runs a fraction of a second for about 1000 times and then takes about 5
> seconds, and then again fraction of a second for about 1000 inserts. There
> are 3 indexes on the table with fillfactor 70.
> Am i right by guessing that at the time when insert takes 5 seconds the
> page splits? Should i decrese fillfactor to 50? Or could it be something
> else?
> Thanks.
>|||1) you can monitor page splits using a perf mon counter. I doubt very much
this is the issue
2) the issue could be log flushes, checkpoints, blocking, something random
hitting the server hard. examine waiting tasks (not sure which version you
are on so can't specify exactly how to do that) when the delay occurs. also
run sp_who2 active to check for blocking.
--
Kevin G. Boles
Indicium Resources, Inc.
SQL Server MVP
kgboles a earthlink dt net
"Michael Kansky" <mike@.zazasoftware.com> wrote in message
news:%23zHWWj$mIHA.5704@.TK2MSFTNGP05.phx.gbl...
>I have a very simple insert statement into a table containing about a
>million rows.
> It runs a fraction of a second for about 1000 times and then takes about 5
> seconds, and then again fraction of a second for about 1000 inserts. There
> are 3 indexes on the table with fillfactor 70.
> Am i right by guessing that at the time when insert takes 5 seconds the
> page splits? Should i decrese fillfactor to 50? Or could it be something
> else?
> Thanks.
>|||I agree with the others that it is probably not related to the fill factor.
I would guess blocking first, disk queues next (checkpoints etc.) and maybe
even file auto growths. Make sure there is plenty of free space in the data
and log files.
--
Andrew J. Kelly SQL MVP
Solid Quality Mentors
"Michael Kansky" <mike@.zazasoftware.com> wrote in message
news:%23zHWWj$mIHA.5704@.TK2MSFTNGP05.phx.gbl...
>I have a very simple insert statement into a table containing about a
>million rows.
> It runs a fraction of a second for about 1000 times and then takes about 5
> seconds, and then again fraction of a second for about 1000 inserts. There
> are 3 indexes on the table with fillfactor 70.
> Am i right by guessing that at the time when insert takes 5 seconds the
> page splits? Should i decrese fillfactor to 50? Or could it be something
> else?
> Thanks.
>|||I see that i have a lot of checkpoints by running a trace.
This might be my problem
How do i minimize checkpoints?
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:u4zPw5AnIHA.4504@.TK2MSFTNGP06.phx.gbl...
>I agree with the others that it is probably not related to the fill factor.
>I would guess blocking first, disk queues next (checkpoints etc.) and maybe
>even file auto growths. Make sure there is plenty of free space in the data
>and log files.
> --
> Andrew J. Kelly SQL MVP
> Solid Quality Mentors
>
> "Michael Kansky" <mike@.zazasoftware.com> wrote in message
> news:%23zHWWj$mIHA.5704@.TK2MSFTNGP05.phx.gbl...
>>I have a very simple insert statement into a table containing about a
>>million rows.
>> It runs a fraction of a second for about 1000 times and then takes about
>> 5 seconds, and then again fraction of a second for about 1000 inserts.
>> There are 3 indexes on the table with fillfactor 70.
>> Am i right by guessing that at the time when insert takes 5 seconds the
>> page splits? Should i decrese fillfactor to 50? Or could it be something
>> else?
>> Thanks.
>|||Checkpoints are there for a reason which is to limit recovery times in the
event of a crash. There is a setting called the recovery interval that can
affect when checkpoints happen but that is not the solution. If checkpoints
hinder the activity that much you do not have proper disk configurations to
handle the load. It sounds like you probably have your tran log files on the
same drive array as the data files. To deal with lots of writes it is
imperative you separate the logs from the data files onto different physical
(not just logical) arrays. Also consider adding more write cache and check
the read / write ratio of the disk controller. If it is not 100% write back
then change it and you will most likely see improvements with checkpoints.
--
Andrew J. Kelly SQL MVP
Solid Quality Mentors
"Michael Kansky" <mike@.zazasoftware.com> wrote in message
news:uo901MBnIHA.4712@.TK2MSFTNGP04.phx.gbl...
>I see that i have a lot of checkpoints by running a trace.
> This might be my problem
> How do i minimize checkpoints?
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:u4zPw5AnIHA.4504@.TK2MSFTNGP06.phx.gbl...
>>I agree with the others that it is probably not related to the fill
>>factor. I would guess blocking first, disk queues next (checkpoints etc.)
>>and maybe even file auto growths. Make sure there is plenty of free space
>>in the data and log files.
>> --
>> Andrew J. Kelly SQL MVP
>> Solid Quality Mentors
>>
>> "Michael Kansky" <mike@.zazasoftware.com> wrote in message
>> news:%23zHWWj$mIHA.5704@.TK2MSFTNGP05.phx.gbl...
>>I have a very simple insert statement into a table containing about a
>>million rows.
>> It runs a fraction of a second for about 1000 times and then takes about
>> 5 seconds, and then again fraction of a second for about 1000 inserts.
>> There are 3 indexes on the table with fillfactor 70.
>> Am i right by guessing that at the time when insert takes 5 seconds the
>> page splits? Should i decrese fillfactor to 50? Or could it be something
>> else?
>> Thanks.
>>
>