sqlparser: support stream specific columns

[derekperkins]

Description

Enable selecting specific columns instead of only stream * from tbl

Related Issue(s)

#6306

Checklist

• Should this PR be backported? - hoping to get it into v13
• Tests were added or are not required
• Documentation was added or is not required

[derekperkins]

I can't get make codegen to run because it won't compile - because of the generated code. What's the workflow to get this to run?

2022/02/10 08:12:54 /Users/derek/go/src/vitess.io/vitess/go/vt/sqlparser/ast_clone.go:1616:37: n.SelectExpr undefined (type *Stream has no field or method SelectExpr)
2022/02/10 08:12:54 /Users/derek/go/src/vitess.io/vitess/go/vt/sqlparser/ast_clone.go:1616:6: out.SelectExpr undefined (type Stream has no field or method SelectExpr)
2022/02/10 08:12:54 /Users/derek/go/src/vitess.io/vitess/go/vt/sqlparser/ast_equals.go:2483:22: a.SelectExpr undefined (type *Stream has no field or method SelectExpr)
2022/02/10 08:12:54 /Users/derek/go/src/vitess.io/vitess/go/vt/sqlparser/ast_equals.go:2483:36: b.SelectExpr undefined (type *Stream has no field or method SelectExpr)
2022/02/10 08:12:54 /Users/derek/go/src/vitess.io/vitess/go/vt/sqlparser/ast_format.go:97:23: node.SelectExpr undefined (type *Stream has no field or method SelectExpr)
2022/02/10 08:12:54 /Users/derek/go/src/vitess.io/vitess/go/vt/sqlparser/ast_format_fast.go:120:7: node.SelectExpr undefined (type *Stream has no field or method SelectExpr)
2022/02/10 08:12:54 /Users/derek/go/src/vitess.io/vitess/go/vt/sqlparser/ast_rewrite.go:4085:37: node.SelectExpr undefined (type *Stream has no field or method SelectExpr)
2022/02/10 08:12:54 /Users/derek/go/src/vitess.io/vitess/go/vt/sqlparser/ast_rewrite.go:4086:20: parent.(*Stream).SelectExpr undefined (type *Stream has no field or method SelectExpr)
2022/02/10 08:12:54 /Users/derek/go/src/vitess.io/vitess/go/vt/sqlparser/ast_visit.go:2026:31: in.SelectExpr undefined (type *Stream has no field or method SelectExpr)
2022/02/10 08:12:54 /Users/derek/go/src/vitess.io/vitess/go/vt/sqlparser/cached_size.go:2112:22: cached.SelectExpr undefined (type *Stream has no field or method SelectExpr)

[GuptaManan100]

Yes, there is a circular dependency, unfortunately right now there is no good way to fix this other than delete those lines from the files (yes the ones which will be generated again and overwritten).

[GuptaManan100]

LGTM!

[derekperkins]

Digging deeper, this doesn't provide much of a win because the whole message row is still loaded into memory, as the message manager can't guarantee that nobody will call stream *. I'll revisit this later with another proposal, probably something around setting visible/invisible columns in the table comments.

[derekperkins]

Thanks to @GuptaManan100 and @systay for helping me debug the ast setup