I can only hope that running my app in dev mode in 3.2 won't bleed memory 40 MB per request. I have no such issues in production environment and it makes testing/debugging a royal pain.
I had a similar issue, which turned out to be a bad Rails plugin, which maintained a few unnecessary pointers to my model classes. The small plugin caused a 20+MB per request leak in development. I rewrote the piece of functionality I needed from the offending module & the issue went away entirely.
Sadly, there isn't really decent memory profiler support to help you track it down. I found the issue by running `git bisect run` with a little script which restarted the server, beat on it a bit with `ab` and then printed memory usage with `ps`. Took me about 10 minutes to track it down to the exact offending commit.
#!/bin/bash
root="/path/to/your/code"
user='postgres'
db='dev'
schema="$root/db/schema.sql"
pg_dump -U $user $db \
--schema=public \
--schema-only \
--no-owner \
--no-privileges \
--file $schema
pg_dump -U $user $db \
--table public.schema_migrations \
--no-owner \
--data-only \
--insert \
>> $schema
And then a small script with 4 or 5 curl calls can get enough data into the database to drive some tests.