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From cmanola...@yahoo.com
Subject Re: cvs commit: jakarta-tomcat/src/share/org/apache/tomcat/modules/server Ajp13.java
Date Tue, 27 Feb 2001 04:49:35 GMT
Hi Dan,

> I do see something which seems like a major gotcha, though -- you remove a
> lot of String creation by creating MessageBytes objects which point directly
> into the underlying input buffer.  *However*, if there is any data posted as
> part of the request, that will immediately overwrite the input buffer (l.
> 376), and any further data which is input will also overwrite the input
> buffer (refillReadBuffer()).

That's why it's great to have the patches reviewed :-)

Yes, you are right.

I don't think it's a problem to add a 8K buffer per Ajp13 thread - as long
as the memory is constant and doesn't result in garbage ( the
getBytes() method is creating a buffer that is garbage-collected )

I'll make sure a different buffer is used for the body.

> course, then you're adding an 8K buffer per Ajp13 thread.  I had thought at
> one point that you could use a single buffer for input and output, but
> that's not the case -- the servlet can be in the middle of reading its way
> through the input stream when it starts to send output back to the browser.

True - using the same buffer for in/out was an idea ( to reduce memory
usage - the fact that GC is taking a lot of time was clear for a long
time), but it turned that the trick is to keep the memory constant and to
not generate garbage.


> Is there a reason you don't want to use your new hBuf Ajp13Packet for
> general output as well as headers?  It kind of looks like you could merge it
> with outBuf (since, even when it's built around an OutputBuffer, it still
> supports appendBytes(), which is all that doWrite() needs).  If you did
> this, you could get rid of one of those 8K buffers per thread.

I guess I do it the wrong way - instead of using 2 buffers for input,
where I should have, I got 2 buffers for output - where it wasn't needed. 
Well, I knew I need 2 buffers :-)

Thank you very much, Dan !

Costin



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