As per discussons on the email lists, PostgreSQL does it this way because this is the safest way to adhere to the standard. Presumably over time cross-CTE opti

As per discussons on the email lists, PostgreSQL does it this way because this is the safest way to adhere to the standard. Presumably over time cross-CTE optimizations will be added. The problem though is guaranteeing the stability the standard requires without doing so. That's a technical issue, not a standards issue though and you are quite right for pointing that out.