explain inside begin; commit;

this:

begin;
explain select * from catalog_items limit 5;
commit;

return this:

-- Executing query:
begin;
explain select * from catalog_items limit 5;
commit;
Query result with 2 rows discarded.


Query returned successfully with no result in 58 ms.

I'm interested in explain inside a transaction because:
1) the query I'd like to explain depends on previous statements
2) it modify the DB and I'd like to keep a consistent state. If the
following queries fail I'd like to roll it back.

explain analyze doesn't make any difference in the output.
I didn't find anything in the log.

Any alternative approach?

--
Ivan Sergio Borgonovo
http://www.webthatworks.it