Re: RelationFlushRelation() or RelationClearRelation()

On 06 Nov 2001 at 19:08 (-0500), Tom Lane wrote:
| I said:
| > Now that I think about it, the problem is almost certainly that the
| > relcache+sinval mechanism isn't recognizing this update as requiring
| > relcache-entry rebuild.  If you update a pg_class row, it definitely
| > does recognize that event as forcing relcache rebuild, and I had thought
| > that updating a pg_attribute row associated with a relcache entry would
| > cause one too.  But maybe not.
| 
| It sure looks to me like the update of the pg_attribute row
| should be sufficient to queue a relcache flush message (see
| RelationInvalidateHeapTuple and subsidiary routines in
| backend/utils/cache/inval.c).  We could argue about whether
| PrepareForTupleInvalidation needs to test for a wider variety of
| relcache-invalidating updates, but nonetheless I don't see why
| renameatt would be failing to trigger one.  Are you sure it's
| not working?

Pretty darned sure that I've accurately described my symptoms.
Doing the tgargs update before or after the actual column update
did not affect the behavior -- the cached relation->triggerdesc
still contains incorrect tgargs.  I'll clean up what I have and 
post a patch for review.

To reply to your earlier email asking what do I expect.

I'd like to be able to say...
 brent# create table parent (id int UNIQUE); brent# create table child (id int4 references parent(id) on update
cascade);brent# alter table parent RENAME id to hello; brent# insert into parent values (1); brent# insert into child
values(1);
 

After running the above and without (re)starting a new backend yields
the following error.  After getting a new backend, the behavior is as 
desired.
 brent=# insert into child values(1); ERROR:  constraint <unnamed>: table parent does not have an attribute id
 brent=# select tgargs from pg_trigger;                              tgargs
----------------------------------------------------------------
<unnamed>\000child\000parent\000UNSPECIFIED\000id\000hello\000
<unnamed>\000child\000parent\000UNSPECIFIED\000id\000hello\000
<unnamed>\000child\000parent\000UNSPECIFIED\000id\000hello\000


Your comments on this matter have been much appreciated.  I'll next
look (further) into the sinval mechanism for a way to forcibly 
invalidate the cached relation->triggerdesc.
 Brent

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