Using large database pages benefits database performance, notably decreasing
I/O time.
Derby automatically
tunes for the database page size. If you have long columns, the default page
size for the table is set to 32768 bytes. Otherwise, the default is 4096 bytes.
You can change the default database page size with the
derby.storage.pageSize property,
described in the "
Derby
properties" section of the
Derby Reference Manual.
For example:
derby.storage.pageSize=8192
Note: Large database pages require more memory.
If row size is large, generally page size should be correspondingly large.
If row size is small, page size should be small. Another rough guideline is
to try to have at least 10 average-sized rows per page (up to 32K).
Use a larger page size for tables with large columns or rows. Maximum page
size allowed is 32k.
However, some applications involve rows whose size will vary considerably
from user to user. In that situation, it is hard to predict what effect page
size will have on performance.
If a table contains one large column along with several small columns,
put the large column at the end of the row, so that commonly used columns
will not be moved to overflow pages. Do not index large columns.
Large page size for indexes improves performance considerably.
