On 2010-02-08 18:42 +0200, Robert Haas wrote: > On Thu, Feb 4, 2010 at 11:57 AM, Marko Tiikkaja > <marko.tiikk...@cs.helsinki.fi> wrote: >> Here's an updated patch. Only changes from the previous patch are >> fixing the above issue and a regression test for it. > > - I'm not sure that canSetTag is the right name for the additional > argument to ExecInsert/ExecUpdate/ExecDelete. OTOH, I'm not sure it's > the wrong name either. But should we use something like > isTopLevelQuery?
I'm going to have to take back my previous statement; this doesn't make a lot of sense in the case of DO ALSO rules (or multiple statements in a DO INSTEAD RULE). Those will have canSetTag=false, but they will be at the top level. > - It appears that we pull out all of the DML statements first and run > them in order, but I'm not sure that's the right thing to do. > Consider: > > WITH x AS (INSERT ...), y AS (SELECT ...), z AS (INSERT ...) SELECT ... > > I would assume we would do x, CCI, do y, do z, CCI, do main query, but > I don't think that's what this implements. The user might be > surprised to find out that y sees the effects of z. I went ahead and implemented this, but there seems to be one small problem: RECURSIVE. If there is a recursive query between those, it might loop forever even if the top-level SELECT only wanted to see a few rows from it. The docs already discourage writing recursive ctes like that, but still this is a small caveat. > - It seems like the gram.y changes for common_table_expr might benefit > from some factoring; that is, create a production (or find a suitable > existing one) for "statements of the sort that can appear within > CTEs", and then use that in common_table_expr. Or maybe this doesn't > work; I haven't tried it. This seems to work. I used PreparableStmt, but I'm not sure how good idea that really is. Maybe I should create a new one? Regards, Marko Tiikkaja -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers