Hey Kym, Thanks for the note. We ended up scrapping the multi-tenant approach in favor of a simpler column based one.
Thanks again, J On Thu, Mar 23, 2017 at 12:41 AM, Kym McInerney < kym.mciner...@airservice.com> wrote: > Hi Julian, > > It's hard to say where your issue is (I'm unfamiliar with PGbouncer) but > yes, setting the search_path on every connection ensures the schema name > spacing remains coherent. > You can get the gist of this at https://github.com/ > holodigm/landlady/blob/master/lib/landlady.rb#L11 > > Regards, > Kym > > > On Friday, March 17, 2017 at 11:24:41 AM UTC+11, Julian Connor wrote: >> >> Hey Kym, >> >> Please allow me to unearth this ancient thread. :) >> >> Last week we attempted to switch to a multi-tenanted approach using the >> Apartment gem and I think we ran into a similar issue. We did a bit of >> testing in our staging environment and everything seemed fine, but when we >> came out of maintenance mode in production, we started seeing a number of >> errors that made it look like the search_path was being lost or incorrectly >> set during the request. >> >> The current theory is that, while under load, our Unicorn workers >> modifying a cached (?) schema_search_path. >> >> Some info on our setup- >> >> Rails 4.2.7.1 >> Ruby 2.1.5 >> Unicorn >> PGBouncer to pool PG connections amongst heroku dynos >> >> We're only using two schemas: grailed and public. The public schema >> contains shared models; users in our case. All other models exist in the >> grailed schema. We were seeing a lot of errors where ActiveRecord >> successfully retrieved a resource out of the grailed schema but was unable >> to follow an association. >> >> E.g., Listing.find(100) would run successfully but >> Listing.find(100).designer would fail, only under load. Both models exist >> in the grailed schema. This behavior leads us to believe that "grailed" was >> being removed from the schema search path before the request could complete. >> >> Does anyone have any insight into why this would happen? Is it as simple >> as reseting the ActiveRecord connection on every request? >> >> We're doing some load testing and trying to reproduce the error on >> another staging machine. We haven't had any success thus far. >> >> Any help is appreciated! >> >> Best, >> Julian >> >> On Friday, November 4, 2011 at 8:19:41 AM UTC-4, Kym McInerney wrote: >>> >>> Hi Robert, >>> >>> I agree with Eric, that Unicorn is losing state on the Postgres >>> session. I'd suggest this is a combination of AREL request caching and >>> new sessions failing to check the subdomain space correctly. In >>> Postgres, set_search_path is also cached. I had a similar issue >>> recently, which was rectified by clearing the ActiveModel connection >>> session on each new session request. With moderate traffic this is OK, >>> for higher traffic not so depending on your underlying architecture. >>> >>> I'd look at how the AREL sessions are handling the Postgres >>> 'set_search_path' as this is why you are getting data from one scheme >>> via another schema sub-domain. In particular look at how apartment is >>> doing this, as apartment only takes the grunt work out of coding the >>> controllers but IMHO doesn't really remove the inherent complexities >>> in multi-controller session handling across schemas. >>> >>> The simplest (and stablest) approach I've found for the sub-domain/ >>> schema 'pattern' in a multitenant app is to create a before_filter >>> subdomain check method in AppController that sets the Postgres search >>> path based on your tenancy namespaces as the request comes in, Rails >>> does the rest and sessions are inherently assigned to a specific >>> namespace through the stack. Benefits are numerous, in particular code >>> maintenance, but this is reusable across asset collections, >>> templating , authentication etc. >>> >>> Also, I found the Postgres adapter for 3.1 is missing a couple of >>> pieces required for stable multi-tenancy, which I believe have been >>> merged into 3.1.1, relating to session schema checking. >>> >>> Cheers, >>> K >>> >>> On Nov 4, 12:31 pm, Robert Hameeteman >>> <robert.hameete...@pageuppeople.com> wrote: >>> > Hi, >>> > >>> > -- The issue -- >>> > We have a multi-tenant system, which identifies the user by an URL- >>> > prefix and database table (This database is excluded from the >>> > apartment model), from the database look-up we select which apartment >>> > (Ruby gemhttp://rubygems.org/gems/apartment) in the Postgres server >>> > to select. >>> > >>> > This system has lately been developed and we encountered issues when >>> > moving onto our pre-production server (Used for user testing, similar >>> > configuration to production). >>> > >>> > Appears under moderate load (Only handful of users accessing both >>> > systems at the same time), the system progressively worsens and >>> > appears after a while to select the wrong apartment. i.e. We are under >>> > Client A URL, but on next page load we get Client B data. >>> > >>> > We have two calls to the database table look up on the page load, one >>> > for the database switching and another to define client styles (This >>> > needs to be fixed later but useful for debugging at the moment.). >>> > >>> > So in addition to the above data mix-up, we have styles mix-up. More >>> > importantly we can have styles from one client and data from another. >>> > >>> > -- Investigation so far -- >>> > We have done some basis analysis so far and found that on the points >>> > where it degrades to the point of mixing up client data (i.e. >>> > selecting wrong apartment) majority of the request is relying on the >>> > table in the seperate database to the apartments which defines which >>> > client is selected.(Approximately 95% or so) >>> > >>> > We have been able to do a hot-fix that has these client values >>> > hardcoded into ruby rather than doing database calls to the shared >>> > database and this has proven to resolve the issue. >>> > >>> > Of course we are looking for a longer term fix, server load times >>> > under these conditions are 50% webserver 50% database. >>> > >>> > -- Server Configuration -- >>> > >>> > We are running our Ruby environment on Unicorn in Rails 3.1 in our UAT >>> > environment, (Step before production with same configuration). >>> > >>> > We have two clients running on this environment, using the apartment >>> > model (http://rubygems.org/gems/apartment) in Postgres server. >>> > >>> > The way we identify which client the user belongs to (They both have >>> > Unique URL's per client), is that we haved a database and table within >>> > that, that sits apart from the apartment model that contains >>> > information regarding all the clients and which URL belongs to either. >>> > >>> > On page load, we check the shared database for which client the URL >>> > belongs to and then do a database switch dependant on the results. >>> > >>> > Any help or tips would be welcome, or if more clarification is >>> > required. >>> > >>> > Cheers ! >> >> -- > You received this message because you are subscribed to a topic in the > Google Groups "Ruby or Rails Oceania" group. > To unsubscribe from this topic, visit https://groups.google.com/d/ > topic/rails-oceania/tvzC85huXEA/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > rails-oceania+unsubscr...@googlegroups.com. > To post to this group, send email to rails-oceania@googlegroups.com. > Visit this group at https://groups.google.com/group/rails-oceania. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Ruby or Rails Oceania" group. 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