Re: BUG: pg_stat_statements query normalization issues with combined queries

Craig Ringer <craig(dot)ringer(at)2ndquadrant(dot)com> writes:
> One suggestion: it's currently non-obvious that ProcessUtility_hook
> gets called with the full text of all parts of a multi-statement.

OK, we can improve that ...

> The same query string may be passed to multiple invocations of ProcessUtility
> if a utility statement in turn invokes other utility statements, or if the
> user supplied a query string containing multiple semicolon-separated
> statements in a single protocol message. It is also possible for the query
> text to contain other non-utility-statement text like comments, empty
> statements, and plannable statements. Callers that use the queryString
> should use pstmt->stmt_location and pstmt->stmt_len to extract the text for
> the statement of interest and should guard against re-entrant invocation.

Not sure about the reference to re-entrancy. It's not especially relevant
to query texts AFAICS, and wouldn't a utility statement know darn well if
it was doing something that could end up invoking another instance of
itself?

regards, tom lane