pg_hint_plan stops parsing on any error and uses hints already parsed on the
most cases. Following are the typical errors.
Any syntactical errors or wrong hint names are reported as a syntax error.
These errors are reported in the server log with the message level specified by
pg_hint_plan.message_level if pg_hint_plan.debug_print is on and above.
Object misspecifications result in silent ignorance of the hints. This kind of error is reported as "not used hints" in the server log by the same condition as syntax errors.
The last hint will be active when redundant hints or hints conflicting with each other. This kind of error is reported as "duplication hints" in the server log by the same condition to syntax errors.
Hint comment cannot include another block comment within. If pg_hint_plan
finds it, differently from other erros, it stops parsing and abandans all hints
already parsed. This kind of error is reported in the same manner as other
errors.