Re: SET SESSION AUTHORIZATION superuser limitation.

We have to be able to emit syntax errors and other things that use the raw SQL text. We also don't have any functionality to turn a parsetree back into SQL text with parts of it masked out, and it'd be impractical to do that just for logging anyway.

I can see it being useful to be able to set a session level flag that limits logging to command tags, not command text. Let the superuser GRANT the right to set it to other users. Use a GUC to toggle it, preferably via SET LOCAL. It has to be session level not statement level because we've got no way to set generic options per-statement, and plus that'd risk leaking the statement on a parse error. We'd probably replace the statement text with a string like 'PARSE_ERROR' until the command tag was known, then replace it with the command tag. This would reduce the audit utility of the logs a little, but if it's superuser-only unless granted you're already stuffed if someone who's not meant to gets hold of it.