Re: Write to outputstream in PGStream blocks indefinitely

Jonas Partner wrote:
> I am having a problem where by my application freezes after a period
> of time under load. Doing a thread dump shows a large number of
> threads seem to be attempting to write to output streams as shown
> below. The application code is attempting to add a single row to a
> table, including binary data of between 3kb - 10kb. This requires a
> restart of the application to clear.
>
> Has anyone else seen similar behaviour? Could this be related to the
> issue discussed in
> http://archives.postgresql.org/pgsql-jdbc/2004-12/msg00096.php where
> the server and driver are filling their respective buffers. If so
> what is the best approach to reducing the likelyhodd of this
> happening.

It seems unlikely that this is the cause if you're only doing a single
update..

Things to try:

- Add '?logLevel=2' to your connection URL -- this should spew lots of
driver debug info to stderr.

- If the data's not sensitive, grab a tcpdump capture (-s 1514 -w
/some/output/file) of a connection that hangs and send me a copy (off-list).

- Attach gdb to the corresponding backend to see what it is doing when
everything stops. Perhaps it's got stuck waiting for a lock, or
something similar?

-O