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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Enable Constraint
If it's a simple 'alter table enable constraint' then it's not building an index, and doesn't even require one on the child table.
Jared
DENNIS WILLIAMS
<DWILLIAMS_at_LIFE To: Multiple recipients of list ORACLE-L
<ORACLE-L_at_fatcity.com>
TOUCH.COM> cc:
Sent by: Subject: RE: Enable Constraint
root_at_fatcity.co
m
12/19/01 11:55
AM
Please respond
to ORACLE-L
Erik - I would assume that underneath Oracle is creating an index. One
thing
to check is the SORT_AREA_SIZE for your database. If it is the default
(64K), then building an index can take a long time.
Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com
-----Original Message-----
Sent: Wednesday, December 19, 2001 1:37 PM
To: Multiple recipients of list ORACLE-L
I am having problems re-enabling a foreign key constraint on a large table.
The table with the foreign key constraint has 20M rows and the parent table
has 1M rows. The foreign key constraint references the primary key of the
parent table. I am surprised that the re-enabling is taking so long -
25minutes. I thought that for each record in the foreign key table, a
lookup
would be done for the existence of a corresponding primary key in the
parent
table. I though that this should be relatively quick due to the fact that
the column is a primary key and therefore indexed. Am I missing something
here? Am I being too critical of the time it takes to do 20M index lookups?
Am I mistaken about how a foreign key constraint is re-enabled?
Any thoughts would be much appreciated.
Thanks
Erik
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Erik Williams INET: ewilliams_at_brownco.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-LReceived on Wed Dec 19 2001 - 17:27:56 CST
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also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: DENNIS WILLIAMS INET: DWILLIAMS_at_LIFETOUCH.COM Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L
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also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: Jared.Still_at_radisys.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L
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