Yuva,
The implementation of the ByteArrayDataSource constructor you are
using looks as follows:
public ByteArrayDataSource(InputStream is, String type) throws
IOException {
ByteArrayOutputStream os = new ByteArrayOutputStream();
byte[] buf = new byte[8192];
int len;
while ((len = is.read(buf)) > 0)
os.write(buf, 0, len);
this.data = os.toByteArray();
this.type = type;
}
As you can see, it will indeed read the entire Blob into a
ByteArrayOutputStream and then copy it to a byte array. It is
therefore not surprising that you run out of memory.
Andreas
On 11 Mar 2008, at 21:42, Chandolu, Yuva wrote:
Hi,
I am trying to replace one servlet serving huge files by a
webservice. When request comes in, the servlet opens InputStream to
the file blob in database, read from the input stream and write to
the http output stream. When client starts pulling the data it comes
straight from the input stream of the servlet (pure streaming). In
which case the Servlet can handle 100s of clients because the
Servlet threads are not trying to load the whole file into memory on
the server side and just sending down the data when it is read from
the client side.
Now I am trying to replace the servlet code by a web service. I am
using DataHanlder for attachements. We have big files in database
(each 10MB or more). When the client call my service
downloadfile(fileName) I need to pull it from the database and
create a datahandler and return to the client. My concern is what
will happen if 100 clients request the all big files (say each 10 MB
in size) using downloadFile() service. My question here is how the
datahandler works, will it read all the file contents from file blob
from database and store in memory before we return it to the client?
Looks like it is because my tomcat is running out of memory when I
tried 20 client threads in parallel requesting for big files. How
can I solve the problem?
Following is my code snippet
Blob file_blob = rs.getBlob(1);
ByteArrayDataSource bds = new
ByteArrayDataSource(file_blob.getBinaryStream(), "application/octet-
stream");
DataHandler data_handler = new DataHandler(bds);
return data_handler;
Thanks in advance
Yuva
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