Re: [HACKERS] Planner drops unreferenced tables --- bug, no?

wieck(at)debis(dot)com (Jan Wieck) writes:
> I think it's correct to MOVE the inFromCl from the relation
> rewritten to the join relations coming with the view's rule.
> Thus clear it on the RTE rewritten and on the first two of
> the rules (which are allways NEW and OLD for all rules). Then
> set all other RTE's which come from the view to the former
> inFromCl state of the rewritten RTE.

OK, I will do that. My first-cut code (attached, please look it over)
passes regress test without it, but we know how much that's worth ;-).

Actually I think moving inJoinSet is now the important thing...

regards, tom lane

All mention of inFromCl/inJoinSet removed from ApplyRetrieveRule;
fireRIRrules loop looks like:

rt_index = 0;
while (rt_index < length(parsetree->rtable))
{
++rt_index;

rte = nth(rt_index - 1, parsetree->rtable);

/*
* If the table is not one named in the original FROM clause
* then it must be referenced in the query, or we ignore it.
* This prevents infinite expansion loop due to new rtable
* entries inserted by expansion of a rule.
*/
if (! rte->inFromCl && rt_index != parsetree->resultRelation &&
! rangeTableEntry_used((Node *) parsetree, rt_index, 0))
{
/* Make sure the planner ignores it too... */
rte->inJoinSet = false;
continue;
}

rel = heap_openr(rte->relname, AccessShareLock);
rules = rel->rd_rules;
if (rules == NULL)
{
heap_close(rel, AccessShareLock);
continue;
}

locks = NIL;

/*
* Collect the RIR rules that we must apply
*/
for (i = 0; i < rules->numLocks; i++)
{
rule = rules->rules[i];
if (rule->event != CMD_SELECT)
continue;

if (rule->attrno > 0)
{
/* per-attr rule; do we need it? */
if (! attribute_used((Node *) parsetree,
rt_index,
rule->attrno, 0))
continue;
}
else
{
/* Rel-wide ON SELECT DO INSTEAD means this is a view.
* Remove the view from the planner's join target set,
* or we'll get no rows out because view itself is empty!
*/
if (rule->isInstead)
rte->inJoinSet = false;
}

locks = lappend(locks, rule);
}

/*
* Check permissions
*/
checkLockPerms(locks, parsetree, rt_index);

/*
* Now apply them
*/
foreach(l, locks)
{
rule = lfirst(l);

RIRonly.event = rule->event;
RIRonly.attrno = rule->attrno;
RIRonly.qual = rule->qual;
RIRonly.actions = rule->actions;

parsetree = ApplyRetrieveRule(parsetree,
&RIRonly,
rt_index,
RIRonly.attrno == -1,
rel,
&modified);
}

heap_close(rel, AccessShareLock);
}