Set lock mode to wait #

Hi all, This may be an obsolete question but "what are the implications of the following statements in concurrency control:" set lock mode to wait 10 update tab_name set.....Any adverse effects if we remove the "set lock mode to wait" statement?. NB: we dont' have "transaction logging" so cannot use "begin work ..... rollback or commit work". Thanks and best regards, Long Nguyen Australian Redcross Blood Service.

You'll start getting lock contention. Commands will fail that otherwise = would have waited their turn for a lock. j. On Mar 20, 2013, at 6:57 AM, Long Nguyen wrote: > Hi all,=20 > This may be an obsolete question but "what are the implications of the=20= > following statements in concurrency control:"=20 > set lock mode to wait 10=20 > update tab_name set.....=20> Any adverse effects if we remove the "set lock mode to wait" = statement?.=20 >=20 > NB: we dont' have "transaction logging" so cannot use "begin work = .....=20 > rollback or commit work".=20 >=20 > Thanks and best regards,=20 > Long Nguyen=20 > Australian Redcross Blood Service.=20 >=20 >=20 > = **************************************************************************= *****=20 > Forum Note: Use "Reply" to post a response in the discussion forum.=20= >=20

If you remove the SET LOCK MODE TO WAIT then if the update encounters any locked records it will abort. Without transaction logging, any rows that it has already updated will remain updated (they cannot be rolled back without logging turned on!) and any rows that would have been updated if the lock were not encountered will NOT be updated. You will have a partially completed 'transaction'. With the LOCK MODE WAIT set the update will wait for ten seconds for any locks it encounters to be released by the other session(s) that are holding those locks before returning an error and aborting increasing the probability that your update will complete without incident. You REALLY should turn logging on! Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Wed, Mar 20, 2013 at 6:57 AM, Long Nguyen <longhuynguyen51@yahoo.com.au>wrote: > Hi all, > This may be an obsolete question but "what are the implications of the > following statements in concurrency control:" > set lock mode to wait 10 > update tab_name set.....> Any adverse effects if we remove the "set lock mode to wait" statement?. > > NB: we dont' have "transaction logging" so cannot use "begin work ..... > rollback or commit work". > > Thanks and best regards, > Long Nguyen > Australian Redcross Blood Service. > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --f46d0444edf1e21db504d85932a9