Note in-line Regards
Jonathan Lewis http://www.jlcomp.demon.co.uk The educated person is not the person who can answer the questions, but the person who can question the answers -- T. Schick Jr Next public appearance2: March 2004 Hotsos Symposium - Keynote March 2004 Charlotte NC - OUG Tutorial April 2004 Iceland One-day tutorials: http://www.jlcomp.demon.co.uk/tutorial.html Three-day seminar: see http://www.jlcomp.demon.co.uk/seminar.html ____UK___February The Co-operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html ----- Original Message ----- To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Wednesday, January 14, 2004 7:09 PM > Interesting, I've actually had to do this before. > > Be forewarned that this is not a good method to use for a very busy > app, as it does introduce some level of serialization. > > control access to the sequence through a package > > Within the package use a function that sets a lock via dbms_lock.request > and then immediately release the lock. > Did you request the lock in share mode to request next val ? This would help to reduce the contention. Normal users would then only queue on the exclusive lock that you would take for the fix-up. lock(shared) increment sequence release > > The purpose of this will become clear in a moment. > > Create a procedure within the package that will be used to reset the > sequence to 0. It is not necessary to drop the sequence to do this. > > eg. > > drop sequence s; > > create sequence s start with 100; > > select s.nextval from dual; > > declare > vs integer; > inc integer; > junk integer; > begin lock(exclusive) > select s.nextval into vs from dual; > inc := 0 - vs; > execute immediate 'alter sequence s minvalue ' || inc; > execute immediate 'alter sequence s increment by '||inc; > select s.nextval into junk from dual; > execute immediate 'alter sequence s increment by 1'; release() > end; > / > > select s.nextval from dual; > > > The procedure that does this just needs to take the same dbms_lock.request > that the function mentioned earlier takes. The difference is that it does > not > release the lock until the modification of the sequence is completed. > > This forces any requests for new sequence numbers to wait for the > modification > to the sequence to complete. > > Jared > > > > > > -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Jonathan Lewis INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
