Re: The future of Java
Martin Gregorie wrote, quoted or indirectly quoted someone who said :
How do you rate H2 against Derby and HSQL?
Roedy Green wrote:
For a comparison of PosGreSQL [sic] and MySQL see
http://mindprod.com/jgloss/postgresql.html
The information is a few years old.
And mentions nothing about Derby or HSQL.
<http://troels.arvin.dk/db/rdbms/>
has a fairly comprehensive comparison of various RDBMSes, but also fails to
mention Derby and HSQL. It has a rather more comprehensive comparison between
PG and MySQL than the mindprod site.
I dispute mindprod's claims that MySQL is "easier to set up" than PG, and
while there may be more books and tutorials on MySQL than PostgreSQL, there is
plenty of information available about the latter so one will not feel the lack.
I understand that Derby is fast, but ram [sic] resident only. It is for
small databases only.
Derby is not RAM resident only.
<http://db.apache.org/derby/papers/pageformats.html>
"Derby stores table and index data in Containers, which currently map to files
in the seg0 directory of the database. In the current Derby implementation
there is a 1 to 1 mapping of containers to files."
<http://db.apache.org/derby/docs/10.5/devguide/>
"A Derby database is stored in files that live in a directory of the same name
as the database. "
As for the size of the database, that is shown in the Developer's Guide at the
above link also:
rows in each table No limit.
size of table No limit.
Some operating systems impose a limit on the size of a single file.
size of row No limit.
Rows can span pages. Rows cannot span tables so some operating systems
impose a limit on the size of a single file, which results in limiting the
size of a table and size of a row in that table.
How well Derby performs at larger sizes is a whole 'nother question, natch.
The documentation has a lot of advice on how to tune Derby performance.
--
Lew