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Home -> Community -> Mailing Lists -> Oracle-L -> RE: exp performance question ( direct=y)
I'd set recordlength to 128 or
64K, depending on your OS....just a read stride...
-----Original
Message-----From: Jim Conboy
[mailto:Jim.Conboy_at_trw.com]Sent: Friday, June 22, 2001 4:28
PMTo: Multiple recipients of list ORACLE-LSubject: RE:
exp performance question ( direct=y)
No, buffer is ignored for
DIRECT=Y. But RECORDLENGTH should be set to DB_BLOCK_SIZE, or a multiple
of it. I've had dramatic gains in performance doing this.
Also, pre-8i you couldn't do
direct-mode export of LONG fields. As of sometime in 8i you can (I know
it works in 8.1.7).
Jim
>>> MohanR_at_STARS-SMI.com 06/22/01 04:00PM
>>>
I dunno. Does the BUFFER
still matter when DIRECT=Y?
If so, I either remove it
entirely, or multiply it by about a factor of five or so.
my $0.02
<FONT face=Tahoma
size=2>-----Original Message-----From: JOE TESTA
[mailto:JTESTA_at_longaberger.com]Sent: Friday, June 22, 2001 3:43
PMTo: Multiple recipients of list ORACLE-LSubject: Re:
exp performance question ( direct=y)
Ron,
ok i'm now confused,
exp direct=n|y
imp no such option
sql_loader has direct also.
or am i missing something here?
joe
>>> RROGERS_at_galottery.org 06/22/01 03:00PM
>>>I thought that DIRECT=Y was for imports only. It makes since
because in the import you are placing the data directly into the blocks with
out a redo log.I have no idea why there was a difference in the times
unless it was the extra overhead for a command that was not used.ROR
mª¿ªm>>> zlmei_at_hotmail.com 06/22/01 12:55PM
>>>Oracle : 8.0.5Platform : SunCurrently we
have cron job every night (starting from 11pm) to do export. I changed
the setting "direct" to "y" two days ago while leaving all other
parameters unchanged, hoping to gain some performance. I am a bit
surprused to find that it did not. It actually took longer to create
dump file with less data to export. The whole exp process takes about 2
hours to finish. Yes, there could be lots of other unix processes
running during that time. But I would still expect to see some
improvement because we are doing this way for quite a while. So my
questions are:1. From your "real" export experience, how much
performance boost did you see when you set "direct=y"?2. If
"direct=y" improves the performance, why would anyone want to use
"direct=n"?Thanks.Guang-- here is my orcle dump
file's time stamp:(dmp.1 and dmp.2 are from direct=y,dmp.3, dmp.4
and dmp.5 are from direct=n).-rw-rw-r-- 1
mt prog
1042197132 Jun 18 01:05 oracle.dmp.5.gz-rw-rw-r-- 1
mt prog
1042375633 Jun 19 01:04 oracle.dmp.4.gz-rw-rw-r-- 1
mt prog
1042556662 Jun 20 00:25 oracle.dmp.3.gz-rw-rw-r-- 1
mt prog
1034773279 Jun 21 01:17 oracle.dmp.2.gz-rw-rw-r-- 1
mt prog
1035237986 Jun 22 01:22 oracle.dmp.1.gz--here is the parameter
file:BUFFER = 64000COMPRESS = YCONSISTENT = NCONSTRAINTS =
YDIRECT = YFILE = /oracle/exports/oracle.dmp.pipe#FULL =
YGRANTS = YINDEXES = YLOG = /oracle/exports/export.logROWS =
YUSERID = xxx/yyyOWNER =
(aaa,bbb)_________________________________________________________________Get
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Please see the official ORACLE-L FAQ: <A
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Guang Mei INET: zlmei_at_hotmail.com Fat City Network
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