Thanks a lot. > ---------- > From: DENNIS WILLIAMS[SMTP:[EMAIL PROTECTED] > Reply To: [EMAIL PROTECTED] > Sent: Saturday, September 06, 2003 7:19 PM > To: Multiple recipients of list ORACLE-L > Subject: RE: Dead locks how ? > > Raj > Imagine two user programs, Joe and Fred. Both need access to table > PAYROLL and EMPLOYEES. First, Joe locks table PAYROLL and processes on it > awhile. Next, Fred locks table EMPLOYEE and processes on it awhile. Then > Joe > attempts to lock table EMPLOYEE. Instead of succeeding, this program > receives a "wait" because Fred has it locked and Joe can't lock it until > Fred releases it. Then program Fred attempts to lock table PAYROLL, but > instead of succeeding that program receives a "wait" because Joe has it > locked. Now both programs are deadlocked and will wait forever. This is > the > simplest form of deadlock. More complex forms involve more users and more > tables. > Some databases require your program to explicitly lock stuff and decide > the levels of locks. Oracle's strength is that if you don't mess with > locks, > it does a pretty good job of avoiding problems. Oracle has built-in > deadlock > detection and some applications will fail from time to time, receiving an > error message to the effect that this isn't Oracle's fault. > Usually applications that are ported from databases that require a lot > of > locking receive the most problems. > As Mladen points out, Computer Science has an entire field devoted to > resource contention, deadlocks, deadlock detection, etc. Whenever a > computer > has multiple processes, there is the potential for contention for > resources. > > Dennis Williams > DBA, 80%OCP, 100% DBA > Lifetouch, Inc. > [EMAIL PROTECTED] > > > -----Original Message----- > Sent: Friday, September 05, 2003 11:14 PM > To: Multiple recipients of list ORACLE-L > > > What is a dead lock ? Does oracle manages with a dead lock or DBA has to > involve ? What are other locks , latches A DBA has to take care of. Any > examples, docs, notes will be helpful. > > Thanks > Rajuveera > ************************************************************************** > > This email (including any attachments) is intended for the sole use of the > intended recipient/s and may contain material that is CONFIDENTIAL AND > PRIVATE COMPANY INFORMATION. Any review or reliance by others or copying > or > distribution or forwarding of any or all of the contents in this message > is > STRICTLY PROHIBITED. If you are not the intended recipient, please contact > the sender by email and delete all copies; your cooperation in this regard > is appreciated. > ************************************************************************** > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: Veeraraju_Mareddi > 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). > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: DENNIS WILLIAMS > 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). > ************************************************************************** This email (including any attachments) is intended for the sole use of the intended recipient/s and may contain material that is CONFIDENTIAL AND PRIVATE COMPANY INFORMATION. Any review or reliance by others or copying or distribution or forwarding of any or all of the contents in this message is STRICTLY PROHIBITED. If you are not the intended recipient, please contact the sender by email and delete all copies; your cooperation in this regard is appreciated. ************************************************************************** -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Veeraraju_Mareddi INET: [EMAIL PROTECTED]
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