Scoping of and/or naming limits of subtables

I have a table which I want to be specific to both the virtual server, and the APM policy which is applicable (it is only written/read during Access Policy event iRules).

 

I tried:

 

table -subtable "[virtual][ACCESS::policy agentid]tablename" ...

 

But this fails when using

 

table -subtable "tablename" ....

 

Works fine.

 

I assume that I'm exceeding the length or other restriction on table name, or possibly I've misunderstood "agent_id".

 

I will try the pragmatic "[virtual]tablename" since the reason to depend on policy is incase the rules change for what is in the table with a policy update, I don't need to worry about deletion or upgrade steps.

 

But if it is obvious to anyone what I've misunderstood here, or if anyone knows the rules for subtable name and length, please shout.