Mike Matrigali: > Øystein Grøvlen wrote: > >For tables with Blob or Clob columns, the default page size for the will > >be 32 kB. > >(Ref. http://db.apache.org/derby/docs/dev/tuning/ctunperf816059.html ) > > Currently Derby will never have 2 different page sizes in the same table > or index. As Oystein points out Derby will automatically choose 32k > page size if it determines at create table time that is appropriate. > Users can override this choice. > > So blobs tend to make page cache bigger because page size is bigger, > nothing really to do with overflow pages.
Thanks for the correction, both of you. =) I saw both 4K and 32K pages in the page cache when only one table was being used, but I guess those 4K pages may have been a primary key index on the table, or maybe one of the internal tables? Now that you mention that Derby will never have 2 different page sizes in the same conglomerate, I realize that I have myself submitted patches where a page's location is calculated as pageNumber * pageSize. Preceded a comment by you, Mike, stating that currently there is no mapping from page number to location other than that simple calculation... So yeah - I should have known. ;-) -- Anders Morken My opinions may have changed, but not the fact that I am right!
