| From: | Andres Freund <andres(at)anarazel(dot)de> |
|---|---|
| To: | pgsql-hackers(at)postgresql(dot)org |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Subject: | Re: generic explain options v3 - RR Review |
| Date: | 2009-07-19 01:15:38 |
| Message-ID: | 200907190315.39139.andres@anarazel.de |
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| Lists: | pgsql-hackers |
Hi Robert, Hi All,
Patch applies with some offset changes, code changes look sensible, I
personally like the new syntax and the features it may allow in future. One,
possibly big, gripe remains though:
The formerly valid statement which cannot be written without the parentheses
and stay semantically equivalent:
EXPLAIN (SELECT 1 ORDER BY 1) UNION ALL (SELECT 2 ORDER BY 1);
is now not valid anymore (The added %prec UMINUS causes the first '(' to be
recognize as start of the option list as intended).
This currently can only be resolved by using an option list like:
EXPLAIN (VERBOSE OFF) ...
Its also currently impossible to use an empty set of parentheses to resolve
this - this could easily be changed though.
I have to admit I don't see a nice solution here except living with the
incompatibility... Perhaps somebody has a better idea?
Andres
PS: The 'offset corrected' version I tested with is attached
| Attachment | Content-Type | Size |
|---|---|---|
| explain_options-v3_offset.patch | text/x-patch | 50.8 KB |
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