Thanks, that's good to know. We have a high rate of inserts into this wide table - page access statistics. In the field we have customers who have experienced slowdowns that we have traced to this insert - a single insert taking several seconds, long enough to make it unusable as part of the site.
Unfortunately we are not able to repro the issue in-house, so I'm just trying to put together as many diagnostics as I can, and I'm new to derby. So I appreciate everybody's assistance! - DAP On Feb 2, 2010, at 9:49 AM, Bryan Pendleton wrote: > Hi David, > >> At what point does derby decide on the pagesize when it is creating a table? > > During the bind processing (compilation) of the CREATE TABLE statement itself. > >> I have a table with several varchar(4000) fields in it. Though they are > > varchar, does derby calculate row size based on the maximum possible column > > size for variable sized columns in deciding whether to bump up the pagesize > > to 32K? > > Yes, Derby bases its calculation on the max column size for VARCHAR, so 4000 > in your case. > > I'm a little surprised that the too-large pagesize would adversely affect > your performance, but you should be able to test it yourself by setting > the derby.storage.pageSize property, as Derby will obey that property even > if you have multiple long VARCHAR columns in your table. > > thanks, > > bryan > > ============================================= David Parker [email protected]
