MSSQL maximum identifier length exceeded

[bojanserafimov]

The maximum identifier (column, alias, or cte name) length in mssql is 128 characters. We currently exceed that limit on queries that are not too crazy in various ways:

1. Columns exposed in a cte are labelled with "_".join(vertex_path) + "__" + used_column_name. This would exceed the character limit in a query with a deep traversal before a @recurse is used.
2. In fold scopes we prepend folded_subquery_ to existing mssql identifiers. This can only be a problem if the existing column name is very long. Looks unlikely and low-priority to me.
3. For table aliases we append _1, _2, etc to an existing table name. This is also unlikely to cause problems, so it's an extremely low-priority issue.

To address the cte column labeling problem, we can simply choose arbitrary or numbered labels. It will work as long as they are unique.

@chewselene please correct me if I'm missing something.

[bojanserafimov]

The identifier limit in OracleDB is 30 characters.

[obi1kenobi]

Do we have type information about the scope identified by such an identifier? E.g. would it be easy to name locations of type Foo with names like Foo_1, Foo_2, Foo_3? While I like the vertex_path naming approach since it makes locations structurally obvious, it's going to be near-impossible to keep that below 30 chars.

We may still need to add some logic to keep identifiers distinct and below 30 chars, but I suspect this is perhaps our best long-term approach.