I have this RoR (2.3.16) app that has a simple agenda tool. Each
customer
has their own individual database, and I have one central database with
login, passwd and the customer database name.
Something like this:
main_database:
users_table:
login_field
passwd_field
database_name_field
customer_db_1:
tables …
customer_db_2:
tables …
So, after user authentication, I set the correspondent database
connection
according each customer.
The problem is:
Customer 1 sometimes see records from customer 2, even being on
different
databases.
I’m totally lost here… I just suspect that this could be a database
connection cache issue, since the SQL query is the same for every
customer
(ie.: select * from agendas;) but the connection string is different for
each one.
Most of the time everything runs ok… but some customers are getting
this
strange behaviour.
On Wednesday, November 20, 2013 4:19:40 PM UTC, Paulo H. Leite de
Castro wrote:
Hi Colin
thanks for your reply!! I’ll try it and see if I can find more info to
help me…
I was also wondering where can I find how Rails (specially 2.3.x) deals
with sql result caching. This could help to diagnose a possible root cause.
There is an sql cache in Rails, however it is scoped to the current
request
you get a fresh cache for each request. When you say that you are
setting
the DB connection after authentication, what exactly are you doing (and
by
authentication do you mean when the user signs in or on every request
once
you have got a user_id from a session/cookie?) ?
Are you checking for an error return here in case it fails for some
reason, leaving the connection as it was for the last request? Also I
presume you are not silently absorbing any exception raised there.
I wasn’t able to find any exception referring to this specific line
code.
But, in case of an exception, Rails would return a 500 error page and
not
the correct page with someone else records. Am I right?
Best regards
Em quarta-feira, 20 de novembro de 2013 14h58min40s UTC-2, Colin L.
escreveu:
didn’t work, but also didn’t throw any exception. So the requested view
got
the last opened database connection to retrieve the records. Of course,
the
records retrieved was from another user (the last
successful establish_connection attempt).
Thank you all for the support!!
Best regards
Em quarta-feira, 20 de novembro de 2013 15h09min18s UTC-2, Paulo
Henrique
Leite de Castro escreveu:
So, for each request I get the current authenticated user database name and
set the connection to customer database.
I would wonder how this plays with connection pooling. In any case,
since you’re explicitly opening the connection, I’d add an after_filter
to explicitly release the connection after using it.
And it might be worth testing whether setting the connection pool
size to 1 changes the behavior. Not that that’s necessarily a great
long-term “solution”, but for troubleshooting purposes.
I expect it returned an error (hence my suggestion to check for error
return). If you look at the docs for establish_connection you will
see that it may throw an exception, but under other circumstances will
return an error.