I'm running a Django 1.8 site, served by nginx and Gunicorn, with a Postgres 9.4 backend.
When I make lots of data-intensive calls to the site's API in succession, I've noticed about 1 in 100 queries failing, and serving up nginx 404 pages.
My first assumption was that the Postgres database was creaking under the load, but the Postgres logs in fact show me this:
2015-08-06 14:33:43 UTC:127.0.0.1(42287):dbuser@dbname:[3737]: LOG: could not send data to client: Broken pipe
2015-08-06 14:33:43 UTC:127.0.0.1(42287):dbuser@dbname:[3737]: STATEMENT: SELECT ... (psql statement)
2015-08-06 14:33:43 UTC:127.0.0.1(42287):dbuser@dbname:[3737]: FATAL: connection to client lost
2015-08-06 14:33:43 UTC:127.0.0.1(42287):dbuser@dbname:[3737]: STATEMENT: SELECT ... (psql statement)
I think what this is saying is that Postgres is actually running the queries OK, but that it can't send data through to the client.
So I think to debug this problem, I should actually look at Django/Gunicorn/nginx instead.
Have I understood this correctly?