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Home -> Community -> Mailing Lists -> Oracle-L -> Re: Parallelism in oracle8i
2 possible reasons
1-Your hint is not working. Type as
select /*+ parallel(ib020mb_3,2) */ adt_date from
--there must be space between + sign and parallel and * else it is
--treated as a comment
ib020mb_3
where adt_date <'01-jun-2000'
2) are your table/indexes analyzed
Hi,
We are doing testing of oracle 8i parallelism features
on unix HP 11 .
We have done 2 partitions on the table ib020mb_3
on a field adt_date with the following details
(partition p1 values less than('22-apr-2000')
tablespace CONTRACT,
partition p2 values less
than('01-jUn-2000')tablespace CONTRACT1).
Each of these partitions are in different tablespace.
Each of this tablespace are on different disks(data
files on different
disk ) in unix environment. We have 4 processors and 4
controllers
(like disk drives) to write on disk.
With this details we are running the following query
with and without
degree of parallelism specified.
select adt_date from ib020mb_3
where adt_date <'01-jun-2000'
But we are taking more time with parallelism. We have
tried the query with
different degrees of parallelism. Currently we are
fetching approx. 15 lac records.
We have tested with a different table and different
set of records but still we
are taking more time with degree of parallelism
specified.
Could you please suggest why we are taking more time .
The following are the tkprof generated for this queries:
select adt_date from ib020mb_3
where adt_date <'01-jun-2000'
call count cpu elapsed disk query
current rows
------- ------ -------- ---------- ------ ------
------ -------
Parse 1 0.12 0.31 21 204 5 0 Execute 1 0.00 0.00 0 0 0 0 Fetch 101340 11.37 16.48 7107 1078260 1520078
Total time taken : 28.28
2)With parallelism:
select /*+parallel(ib020mb_3,2)*/ adt_date from
ib020mb_3
where adt_date <'01-jun-2000'
call count cpu elapsed disk query
current rows
------- ------ -------- ---------- ------ -------
------ ------
Parse 1 0.13 0.61 21 243 6 0 Execute 1 0.00 0.00 0 0 0 0 Fetch 101340 11.72 16.79 7107 1078260 1520078
Total time taken :29.25
Thanks In Advance
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