Yes, function based indexes are great. You MUST use the CBO, so if this is
a vender appliction (eg Siebel) that requires you to use the RBO then you
are screwed with that method. In which case you have to resort to the
phantom column approach. :-( Raid 5 is notorious for a write penalty. Let
me guess IT built the box for you with out input from the DBA.
Jim
--
Replace part of the email address: kennedy-down_with_spammers_at_attbi.com
with family. Remove the negative part, keep the minus sign. You can figure
it out.
"Gary Avery" <Gary.P.Avery_at_Pharmacia.com> wrote in message
news:3e3aa1ff$0$209$1406d58a_at_newsread.pharmacia.com...
> Dear board,
>
> here is some of the output from a statspack report I ran (went on the
> Performace/Tuning course last week)
>
> Snap Length
> (Minutes)
> -----------
> 168.90
>
>
> Top 5 Wait Events
> ~~~~~~~~~~~~~~~~~ Wait %
> Total
> Event Waits Time (cs) Wt
> Time
> -------------------------------------------- ------------ ------------ ---
--
> --
> db file sequential read 524,735 235,947
> 76.07
> db file scattered read 157,554 48,837
> 15.75
> db file parallel write 1,993 8,248
> 2.66
> db file parallel read 2,217 5,562
> 1.79
> control file sequential read 14,152 3,896
> 1.26
>
> If I read this right, then of the 168 minutes that the snap was taken the
> highest 2 waits accounted for 47 minutes of the snap. Now to me that seems
> an awful lot and I beleive I ought to be looking at what sql is being
> performed against the tables to see if there are some obvious indexes
> missing. Is this what i should be doing or are there other 'quicker' gains
> to be made elsewhere. (I have already up'd the db_file_multiblock_read
> count)
>
> We run a multi-purpose application with all the datafiles stored on a
single
> raid5 array (NT).
>
> Also has anyone done much with function based indexes? Would an index on
> UPPER(surname) gave a dramatic increase to selects...where surname like
> (upper(blah)). we tend to do a fair amount of those.
>
> regards
>
> Gary
>
>
Received on Fri Jan 31 2003 - 10:55:03 CST
