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Insert difference

Author

Topic

shaggy
Posting Yak Master

248 Posts

Posted - 2013-03-30 : 06:42:26

Can anyone absorb the difference between the two same insert statements

The insert staments are same running in while loop but the differenec is 1st insert is without transaction taking long time to complete 2nd insert is fast i have included the transaction

For 1st insert I've absorbed the (X) lock on RID and (IX) on PAGE & Object and the lock is getting released and acquiring lock on another RID and so on its going till end (100000).

For 2nd insert completed in a second holding (100000) RID (X) lock
(IX) on some x pages and (IX) on Object.

I want to what is the differnec between them. internally what is happening because of lock acquired and relaesed and again acguiring
is causing the 1st insert to slow down ?

Is that we have to include transaction for whennever we insert bulk records ?

Create table testtable (col1 int)

--Insert statement 1
declare @col1 int = 0
while @col1 <=100000
begin

insert testtable select @col1

select @col1 = @col1 + 1
end

--Insert statement 2
Drop table testtable

declare @col1 int = 0
begin tran
while @col1 <=100000
begin

insert testtable select @col1

select @col1 = @col1 + 1
end
commit

James K
Master Smack Fu Yak Hacker

3873 Posts

Posted - 2013-03-30 : 18:46:29

It could also be because in the first one each insert is a transaction - which means each insert needs to be persisted to the log file. That results in a lot of small writes to the log. In the second case, SQL Server can afford to not persist any of the inserts until the end of the loop when you are ready to commit.

In any case, if you want to insert 100,000 rows to a table, you should see if there is a way to do it as a set based operation instead of a while loop.

shaggy
Posting Yak Master

248 Posts

Posted - 2013-04-01 : 04:43:29

Thanks James

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