Informatica Bulk Mode behavior 2004-04-23 - By Thomas Jeff
That 's not the case here though --- we eliminated the indexes entirely
to try and
isolate the culprit.
-- --Original Message-- --
From: oracle-l-bounce@(protected)
[mailto:oracle-l-bounce@(protected)] On Behalf Of
Rajesh.Rao@(protected)
Sent: Friday, April 23, 2004 5:32 AM
To: oracle-l@(protected)
Subject: RE: Informatica Bulk Mode behavior
Well Mohan, You are under the impression, I am stating the obvious. But
If you read my email again, you would see that I said "twice the space "
and "temporary " segments.
Say, you have an index of size 2Gb, and you insert 2 Mb of index keys,
Oracle will create a NEW TEMPORARY segment of size 2 Gb+2 MB in the same
tablespace. So, at one point, the index will occupy 2Gb(old
space)+2Gb(new TEMPORARY segments)+2Mb of space(new index keys). Once
the new index is built, the old one will be dropped, and you should now
the index occupying only 2Gb+2Mb of space. Hence, my reasoning that the
indexes could be the reason for the tablespace filling up.
I DIRECT you to read Note 50592.1 ;-)
Regards
"Mohan, Ross "
<RMohan@(protected) To:
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Informatica Bulk Mode behavior
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04/22/2004 04:28 PM
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oracle-l
Whereas with regular indexes they don 't take space? ;-) Believe if you
have, as one example, a FULLY packed, fresh index on tab(col) with
pctfree 0 and defaulted freelisting and add a few thousand rows via
APPEND you are going to get the same resultant index size if you added
the rows via conventional means.
...your experiences may well be different, but....just a wayt of saying
that mostly the pctfree of the idx and its freelists config will drive a
lot of the space (mis?)usage.
HTH
-- --Original Message-- --
From: Rajesh.Rao@(protected) [mailto:Rajesh.Rao@(protected)]
Sent: Thursday, April 22, 2004 2:34 PM
To: oracle-l@(protected)
Subject: RE: Informatica Bulk Mode behavior
One thing of note that I have encountered with Direct Load Inserts is
that the Indexes on the table will require twice the space. Say, you
have indexes of size 2 Gb, then after the direct insert, the exisiting
index is merged onto a "temporary " segment along with the new index
keys. So, check if you are running out of space coz of the indexes.
Regards
Raj
"Khedr, Waleed "
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Multithread is a way Informatica can parallelism the load into the =
target using many concurrent sessions. Since it 's direct load, each
session will try to allocate its own = extents to load into.
I would check if they have a very high number of threads.
But also since you said the job failed and the table was loaded with =
some rows (200K), this indicates that they have low setting for the =
commit interval otherwise the table will be empty.
Commit interval should be very high 1 million or higher.
Waleed
-- --Original Message-- --
From: Thomas Jeff [mailto:jeff.thomas@(protected)]
Sent: Thursday, April 22, 2004 12:23 PM
To: oracle-l@(protected)
Subject: RE: Informatica Bulk Mode behavior
Waleed,
The tablespace is locally-managed, 128MB extents. I 'll have to ask
about the multithread, can you
tell me the ramifications of it?
Thanks.
-- --Original Message-- --
From: oracle-l-bounce@(protected)
[mailto:oracle-l-bounce@(protected)]
On Behalf Of Khedr, Waleed
Sent: Thursday, April 22, 2004 10:24 AM
To: oracle-l@(protected)
Subject: RE: Informatica Bulk Mode behavior
I use it. It 's using direct load OCI.
Never had your problem.
What is the extent size (initial/next ) for the table? Are they using =
=3D =3D3D multithread in the mapping?
Waleed
-- --Original Message-- --
From: Thomas Jeff [mailto:jeff.thomas@(protected)]
Sent: Thursday, April 22, 2004 10:33 AM
To: oracle-l@(protected)
Subject: Informatica Bulk Mode behavior
List,
Is anyone familiar with how Informatica 's bulk mode works? =3D3D20
We have a situation where I created a 4GB tablespace for a new and
simple=3D3D20 truncate/load operation from Informatica, around 7 million
rows estimated=3D3D20 to take up 1.5GB. =3D3D20 =3D3D20 Using bulk =
mode, =3D which appears to be a direct load (in the SQL cache,
the=3D3D20 INSERT = statement has a hint that I 've never seen before:
SYS_DL_CURSOR which=3D3D20 I = =3D assume stands for Direct Load), they
run out of space in the tablespace after=3D3D20 about 200K rows have
been inserted.
If I then manually rebuild the table, the 200K rows gets compressed back
down=3D3D20 to one extent.
So there 's a lot of either empty or preallocated space. Thinking
somehow=3D3D20
the high-water mark was the culprit, I manually truncated the table
before=3D3D20 they reran their job. =3D3D20
Still the same problem. =3D3D20
If the job runs in 'normal ' mode, which is row-by-row processing, it
runs fine,=3D3D20 although of course, performance is quite poor.
Any ideas/experience as to how this bulk mode operates?
Thanks.
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