Jeffrey Tenny wrote:
> I've been working to minimize the memory footprint of my application.
> I was under the impression that ResultSet.getBinaryStream would be more
> efficient than getBytes(). Certainly the documented semantics imply
> that that is a goal (since you must process the InputStream from
> getBinaryStream before the call to ResultSet.next() or even processing
> the next column.
>
> But the following trace from a java heap profile suggests
> that we're still just copying the bytes from the resultset as with
> getBytes() instead
> of streaming the ones already in memory, though perhaps it's because
> I'm using a read(buf) call on the stream.
The intermediate copy happens because the "in memory" version is a
text-escaped representation of the bytea value, not just a straight
bytearray.
getBinaryStream() could indeed be smarter, avoiding the intermediate
bytearray by decoding the text representation on demand. But noone has
implemented this yet.
Probably a better long-term solution is to move to binary-format results
at the protocol level. That's somewhere on my todo list, but I'm not
making much progress on it at the moment.
-O
