I’m troubleshooting a problem, and I would love some help
understanding what is going on.
The problem is that Mongrel/Rails appears to hang or completely block
if one of the users initiates a very slow, long-running query (via an
ad-hoc report generation tool from within the app).
For example, user A does a big query that takes minutes to complete.
User B tries to do anything, but Rails seems completely dead.
Should Rails be blocking on that query, effectively a single-user
server? (I certainly wouldn’t expect this…)
Secondly, for what it’s worth, I’m running a mongrel cluster, but that
isn’t helping right now.
“top” shows the host machine completely idle.
development.log shows only user A’s query SQL, but it does not show
user B’s request for a new page.
When user A’s query finally completes, then suddenly Rails comes back
to life, and user B gets a response.
This is a serious problem for me right now. It must be a
configuration problem, because there’s no way Rails is designed to
behave this way…?
Oh also, the database is hosted on another machine, and it’s Oracle 9.