user manual

52 BES Developer’s Guide
Large data transfer
If you do not want the Borland web container to perform this buffering
behavior, you can set the IIOP connector attribute canBufferHttp10Data="false".
By default, this attribute is set to true.
Note When the canBufferHttp10Data attribute is set to false, the following error
message is sent to the browser:
Servlet did not set the Content-Length
Implementing non-chunked download
This is the default transfer of data mode for the IIOP connector. In the non-
chunked download mode, the Borland web container waits until it has all the
data to send. Then it calculates the content length and sets the Content-Length
header to the actual content length. The Borland web container then sends the
response header followed by a single huge data block.
This mode of transfer has high memory requirements both on the Apache web
server and the Borland web container, because the data is cached until all of it
is available. Only when all the data is transferred does the browser user see
the data.
The non-chunked download mode of transfer has no overhead of extra thread
per each request. This download mode works well under both the HTTP
protocol versions 1.0 and 1.1, because the Transfer-Encoding header is never
set in this mode.
Uploading large data
The following modes are available for uploading large data initiated by a client
(which can be either a browser or a non-browser (such as Java) client that
speaks HTTP):
■
Chunked upload
■
Non-chunked upload
The browser always sends the data to an Apache web server in a "chunked"
fashion. Chunked and non-chunked upload refers to the data transfer mode
between an Apache web server and a Borland web container.
Implementing chunked upload
By default, Apache will try to upload large size data in "chunks". In this mode,
Apache does not wait until it has all the data from the browser before it starts
sending data to a Borland web container. Apache sends the data in fixed size
buffers as the data becomes available from the browser.
Because the data is flushed as soon as possible, the chunked mode of upload
transfer has low memory requirements both on Apache and the Borland web
container.
The chunked mode of transfer has an overhead of an extra thread per each
request on the Borland web container?.