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parallel update and db file scattered read

From: hopehope_123 <hopehope_123_at_yahoo.com>
Date: 6 Nov 2005 23:40:12 -0800
Message-ID: <1131349212.287019.33110@z14g2000cwz.googlegroups.com>


Hi Gurus ,

One of my parallel queries( update statement) uses db file scattered read.
But according to the documents , parallel query uses direct path read and
bypasses the sga for full table scans.

Here is my sql:
UPDATE opet_trx o
SET (o.dwh_paro_kod, o.last_update_date) = (SELECT tk.dwh_verde_kod, sysdate
FROM opet_tuketici tk
WHERE tk.kart_no = o.kart_no)

and these are the session information:
select * from gv$session_Wait where sid=99 order by event INST_ID SID SEQ# EVENT P1TEXT P1 P1RAW P2TEXT P2 P2RAW P3TEXT P3 P3RAW WAIT_TIME
SECONDS_IN_WAIT STATE
2 99 57251 db file scattered
read file# 105 0000000000000069 block# 179294 000000000002BC5E blocks 8 0000000
0
00000008 0 0 WAITING
select * from gv$px_session where sid=99 INST_ID SADDR SID SERIAL# QCSID QCSERIAL# QCINST_ID SERVER_GROUP SERVER_SET SERV
ER# DEGREE REQ_DEGREE
2 000004002E510B60 99 13287 191 4046 1 1 1 8 8 8 select inst_id,sid,event,p1,p2,p3 from gv$session_Wait where sid in ( select sid from gv$px_session where qcsid=191) order by event
INST_ID SID EVENT P1 P2 P3
2 24 db file scattered read 99 193881 8
2 43 db file scattered read 104 181105 8 2 104 db file scattered read 97 203873 8 2 99 db file scattered read 97 892934 8
2 194 db file scattered read 101 189065 8 2 139 db file scattered read 101 189081 8 2 144 db file scattered read 97 893270 8 2 166 db file scattered read 105 177721 8 1 141 db file sequential read 121 172524 1 although the query runs parallel , it uses db file scattered read so sga.
Under what circumstances does oracle use sga / 'db file scattered read 'with
parallel query?
Kind Regards,
tolga Received on Mon Nov 07 2005 - 01:40:12 CST

Original text of this message

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