Re: Table Locks in OnLine 7.x

Mark Goldin wrote: > Does anyone know under which query circumstances OnLine will lock a table? > The manual makes a brief mention of this but provides no examples. I > suspect that aggregate queries may place some kind of table lock. If this > is true, does it depend on isolation levels? Is there some other way to > avoid locking the entire table? This would be similar to lock escalation in > SQL Server which CAN be circumvented. > > Mark Off the top of my head the only times Online would put either an S (share) lock or X (exclusive) lock on a table would be these: 1) running oncheck -cD or -cI against a table 2) building an index against a table 3) onunloading a table 4) alter table (not in using the in-place algorythm) The 1 other case I can think of is if you had your isolation level set to repeatable read and you kicked off a query that had to do a sequential scan of the table, I think we put a S lock on the table instead of individual S locks on all the rows of the table. I'm probably missing some other operations, but it sounds like you might be hitting the S lock from using repeatable read? Jacques -- ******************************************************************** * Jacques P. Renaut "I'd dazzle you with brilliance * * Informix Advanced Support if I only had the knack..." * * email: jrenaut@informix.com #include <disclamier.h> * ********************************************************************