Wednesday, July 20, 2011

Java BufferedInputStream Problem

I ran into a problem loading a large database dump from cSuneido into jSuneido.

After several hours of debugging, I found if I changed this:

InputStream fin = new BufferedInputStream(
    new FileInputStream(filename));


InputStream fin = new FileInputStream(filename);

(i.e. removed the BufferedInputStream)

Then it worked ?!

I searched on the web for BufferedInputStream problems but didn't find anything relevant.

One thing that is suspicious is that this is probably the first file I've tried to load that is larger than 4 gb (i.e. the limit for a 32 bit integer), although I'm not sure why that would be a problem for BufferedInputStream. You'd think it would just be reading sequentially. Unless it's trying to do something clever like memory mapping the whole file.

Note: This is on a 64 bit JVM.

I'm just going to omit the BufferedInputStream for now, but it would be nice to know why there was a problem.

I guess I could go dig up the OpenJDK code for BufferedInputStream but I'm not that motivated.

Anybody have any information or thoughts on this?

No comments: