db-derby-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Mark Thornton <mthorn...@optrak.co.uk>
Subject Re: Derby speedup by not using page caches?
Date Mon, 02 Mar 2009 11:46:48 GMT
Knut Anders Hatlen wrote:
> No, there's no way to do that currently. There is an old JIRA issue for
> using memory mapped files (DERBY-262), but there hasn't been much
> activity yet.
> For databases, the problem with double caching has traditionally been
> solved by disabling the cache for the file system on which the database
> is stored (that is, enabling direct I/O on that file system). That is
> however a solution that fits better for a dedicated database server than
> for a (zero-admin) database embedded in a desktop application.
> I think there is more to it than just disabling the page cache and using
> memory mapped files. Some of the challenges I see are:
An easier target would be to use memory mapping for read only databases. 
There are a number of awkward issues with Java's memory mapping when the 
map is writable

Mark Thornton

View raw message