Performance dropped after upgraded to MS SQL 2000

Dear all,
Last Saturday, I upgraded my SQL 7.0 database to SQL 2000 Standard Edition
succesfully.
I also executed "sp_updatestats" and reindexed all the databases, but I
found the server's overall performance is worse than before.
That means SQL 2000 is slower than SQL 7.0, why ?Possibly you have bad luck with some queries for which SQL Server picks less
good execution plans in
2000 compared to 7.0. You need to work those queries and see why. One plausi
ble reason is below:
WHERE col = value
If col and value (or parameter or variable) aren't of the same datatype, the
n 7.0 would convert the
non-column side toe the column datatype. 2000 converts more correctly, accor
ding to datatype
precedence documentation in Books Online. This can case your queries be effe
ctively the same as:
WHERE CAST(col AS dt) = value
And since the column side isn't alone (it is wrapped in a function), typical
ly index on that column
cannot be used.
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://www.solidqualitylearning.com/
"John" <cpjohn@.netvigator.com> wrote in message news:d7cem9$b4i20@.imsp212.netvigator.com...[
vbcol=seagreen]
> Dear all,
> Last Saturday, I upgraded my SQL 7.0 database to SQL 2000 Standard Edition
> succesfully.
> I also executed "sp_updatestats" and reindexed all the databases, but I
> found the server's overall performance is worse than before.
> That means SQL 2000 is slower than SQL 7.0, why ?
>
>[/vbcol]|||Thanks a lot.
I will try it.
"Tibor Karaszi" <tibor_please.no.email_karaszi@.hotmail.nomail.com> wrote in
message news:O5p6mi0ZFHA.3784@.TK2MSFTNGP12.phx.gbl...
> Possibly you have bad luck with some queries for which SQL Server picks
less good execution plans in
> 2000 compared to 7.0. You need to work those queries and see why. One
plausible reason is below:
> WHERE col = value
> If col and value (or parameter or variable) aren't of the same datatype,
then 7.0 would convert the
> non-column side toe the column datatype. 2000 converts more correctly,
according to datatype
> precedence documentation in Books Online. This can case your queries be
effectively the same as:
> WHERE CAST(col AS dt) = value
> And since the column side isn't alone (it is wrapped in a function),
typically index on that column
> cannot be used.
> --
> Tibor Karaszi, SQL Server MVP
> http://www.karaszi.com/sqlserver/default.asp
> http://www.solidqualitylearning.com/
>
> "John" <cpjohn@.netvigator.com> wrote in message
news:d7cem9$b4i20@.imsp212.netvigator.com...
Edition[vbcol=seagreen]
>