Re: missing locking in at least INSERT INTO view WITH CHECK

On 27 August 2015 at 12:18, Andres Freund <andres@anarazel.de> wrote:
> On 2013-10-24 20:58:55 +0100, Dean Rasheed wrote:
>> So I
>> think the only thing missing from rewriteTargetView() is to lock any
>> relations from any sublink subqueries in viewquery using
>> acquireLocksOnSubLinks() -- patch attached.
>
> This is still an open problem :(
>

Oh yes, I forgot to follow up on this.


>> diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
>> new file mode 100644
>> index c52a374..e6a9e7b
>> *** a/src/backend/rewrite/rewriteHandler.c
>> --- b/src/backend/rewrite/rewriteHandler.c
>> *************** rewriteTargetView(Query *parsetree, Rela
>> *** 2589,2594 ****
>> --- 2589,2604 ----
>>       heap_close(base_rel, NoLock);
>>
>>       /*
>> +      * If the view query contains any sublink subqueries, we should also
>> +      * acquire locks on any relations they refer to. We know that there won't
>> +      * be any subqueries in the range table or CTEs, so we can skip those, as
>> +      * in AcquireRewriteLocks.
>> +      */
>> +     if (viewquery->hasSubLinks)
>> +             query_tree_walker(viewquery, acquireLocksOnSubLinks, NULL,
>> +                                               QTW_IGNORE_RC_SUBQUERIES);
>> +
>> +     /*
>>        * Create a new target RTE describing the base relation, and add it to the
>>        * outer query's rangetable.  (What's happening in the next few steps is
>>        * very much like what the planner would do to "pull up" the view into the
>
> These days this seems to require a context parameter being passed
> down. Other than that this patch still fixes the problem.
>

Yes, I concur. It now needs an acquireLocksOnSubLinks_context with
for_execute = true, but otherwise it should work.

I have a feeling that RLS might suffer from the same issue, but I
haven't looked yet.

Regards,
Dean