Re: VariableSchemaSupport unnecessary slow

Roché Compaan wrote:
> Hi there
> 
> Yesterday some of my colleagues and I ran profiler while re-indexing
> content types that subclass VariableSchemaSupport. We discovered that
> the hash created when caching the schema is making things very very
> slow. Here is the relevant code:
> 
>         # create a hash value out of the schema
>         hash=sha.new(str([f.__dict__ for f in s.values()]) +
>                      str(self.__class__)).hexdigest()
> 
> I understand that the above code ensures that we always have a fresh
> schema and that nobody else has to do anything in their code, but the
> price on has to pay in performance is simply to high. I would recommend
> that we use a very simple mechanism where the schema is cached upon
> access and invalidated when it changes.

And VariableSchemaSupport caching seems to be broken anyway.

Using Plonemall - that subclasses VariableSchemaSupport - we never got a 
cache hit with VariableSchemaSupport. Instead it stored what should be 
the same fields multiple times in the cache (the module level 
schemadict) and introduced a severe memory leak. The ref counts and 
memory usage just grew and grew.

Removing the cache fixed it for us.

/Anton Stonor