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Derby database limitations
Derby databases
have a few limitations.
IndexesIndexes are not supported for columns defined
on CLOB, BLOB, LONG VARCHAR, and XML data types.
If the length of the
key columns in an index is larger than half the page size of the index, creating
an index on those key columns for the table fails. For existing indexes, an
insert of new rows for which the key columns are larger than half of the index
page size causes the insert to fail.
Avoid creating indexes on long
columns. Create indexes on small columns that provide a quick look-up to larger,
unwieldy data in the row. You might not see performance improvements if you
index long columns. For information about indexes, see Tuning Derby.
System shutdownsThe system shuts down if the database
log cannot allocate more disk space.
A "LogFull" error or some sort
of IOException occurs in the derby.log file
when the system runs out of space. If the system has no more disk space to
append to the derby.log file, you might not see the error
messages.
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