Обсуждение: "disappearing" rows in temp table, in recursing trigger
Hello, I'm guessing the rows aren't really disappearing but how else to describe it?.... I have a trigger function that calls another function that is recursive. The recursive function creates a temp table and inserts rows into it. After the recursive function returns, the trigger function examines the temp table in order to validate the data in it. This all works perfectly well when the trigger function is written slightly modified as a regular function. However when run as a trigger, the temp table comes back empty. No errors are thrown. I have version 8.1.10. I've tried to include the relevant parts below. Any smarty out there see the problem? --Eric --========= --The trigger is like this: CREATE TRIGGER trigger_name AFTER INSERT OR UPDATE ON table_name FOR EACH ROW EXECUTE PROCEDURE trigger_func() --======== --The trigger_func() (abbreviated): begin perform recursive_func(new.id, 1, new.id); l_row_count := count(*) from tmp_ancestors; raise debug 'total rows=%', l_row_count; --LOG OUTPUT SAYS: "total rows=0" .... return new; end; ======== --The recursive_func(): begin .... insert into tmp_ancestors (blah, blah)... if logic then new_level := p_level + 1; perform recursive_func(id, new_level, id); end if; l_row_count := count(*) from tmp_ancestors; raise debug 'returning p_level=%; rows in tmp_ancestors=%', p_level, l_row_count; --LOG OUTPUT SHOWS EXPECTED INCREMENTING NUMBERS return; end
Eric Worden wrote: > The recursive function creates a temp table [...] I > have version 8.1.10. While I haven't looked in detail, I'd be surprised if this wasn't an issue with pre-8.3 versions lack of any way to automatically re-generate cached plans in functions. Try running your code on an 8.3 installation and see if you still get the issue. I strongly suspect you won't. If this does prove to be the case, there are workarounds for pre-8.3 versions, usually involving the use of EXECUTE to bypass the cache and force re-planning of statements at every execution. However, if it's practical to do so upgrading to 8.3 might be a nicer and (in the long run) easier option. -- Craig Ringer
Thank you this helped me fix it. I moved the "create temporary table..." statement to the outermost calling function and changed it from STABLE to VOLATILE. I'm not sure which change made the difference -- I had to move the create table statement for an additional reason. On Sat, Dec 27, 2008 at 1:14 AM, Craig Ringer <craig@postnewspapers.com.au> wrote: > Eric Worden wrote: > >> The recursive function creates a temp table [...] I >> have version 8.1.10. > > While I haven't looked in detail, I'd be surprised if this wasn't an > issue with pre-8.3 versions lack of any way to automatically re-generate > cached plans in functions. > > Try running your code on an 8.3 installation and see if you still get > the issue. I strongly suspect you won't. > > If this does prove to be the case, there are workarounds for pre-8.3 > versions, usually involving the use of EXECUTE to bypass the cache and > force re-planning of statements at every execution. However, if it's > practical to do so upgrading to 8.3 might be a nicer and (in the long > run) easier option. > > -- > Craig Ringer >
"Eric Worden" <worden.eric@gmail.com> writes: > Thank you this helped me fix it. I moved the "create temporary > table..." statement to the outermost calling function and changed it > from STABLE to VOLATILE. I'm not sure which change made the > difference -- I had to move the create table statement for an > additional reason. Probably the latter. STABLE functions generally use the snapshot of the calling query, which means that on successive calls they'll see the same state of the database. regards, tom lane