Strange Postgres Behaviour with Session Variables

Can someone explain why Rails is querying the Postgres database every
time I retrieve a session variable?? The query is to determine the
attributes of the model object I guess and looks like this: “SELECT
a.attname, format_type(a.atttypid, a.atttypmod), d.adsrc, a.attnotnull
FROM pg_attribute a LEFT…”.

Like I said, this SELECT only occurs when I load a variable such as:
@value = session[:value]

The behaviour seems wrong since it wasn’t occurring using MySQL


I still haven’t found any reason for this. Any ideas??