Re: Implementing DBMS in Java

san wrote:
> I was wondering if the new io facilities provided by JDK1.4 would make
> java a suitable language to write a database engine in.

Sandeep,

Java has been a suitable language to write a database engine in for a long time. There are quite a few products that are in use and performing well. Some of them in alphabetical order:

Cloudscape
db4o
FirstSQL
HSQL
InstantDB
McKoi
Ozone
Pointbase

> Java lacked scalable io and features like MemoryMapped files
> before JDK1.4.

Not all database storage concepts profit from memory mapped files.

Even before JDK 1.4 it was possible to write a native file io library and to supply it as open source, to enable users to implement it on the platform of their choice. Reading and writing file blocks is not all that complex.

> My main concern is IO speed with respect to something like C or C++.
> Does anyone have concrete benchmark tests for JDK1.4 (NOT 1.3 or
> lower) comparing it with C++?

We haven't been testing too much of JDK 1.4 NIO yet but from reading along in newsgroups it seems to perform completely different on different operating systems.

Kind regards,
Carl

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Carl Rosenberger
db4o - database for objects - http://www.db4o.com