I came across a very nice example a while ago where there were 4 concurrent sessions feeding data into a holding table, and one session consuming from the table.
The rules said that the consumer could not run while the producers were loading the table, but multiple producers were allowed to run. It was easy to implement using dbms_lock - the producers ran a pl/sql loop that requested a share lock (mode 4) on a named resource, and committed at the end of each loop; the consumer also ran a loop but requested an exclusive lock (mode 6) on the same named resource and committed at the end of each loop. Both programs had a little sleep time built in to the loops after the commit. When the consumer got its lock, the producers waited. When the consumer committed, the producers got in, and the the consumer queued on them when it next asked for its lock. 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 appearances: Jan 29th 2004 UKOUG Unix SIG - v$ and x$ March 2004 Hotsos Symposium - The Burden of Proof March 2004 Charlotte NC OUG - CBO 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: Thursday, January 22, 2004 4:39 PM > Well, I don't know about anyone else, but I make use of it to synchronize data upload programs for our testers. Can't have two instances of the upload program processing the same tester, they'd duplicate data. Anyhow, we normally run 4 instances of this program & the dbms_lock package works absolutely fantastically. > > Dick Goulet > Senior Oracle DBA > Oracle Certified 8i DBA -- 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).
