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Get rid of the "new" and "old" entries in a view's rangetable.

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The rule system needs "old" and/or "new" pseudo-RTEs in rule actions
that are ON INSERT/UPDATE/DELETE.  Historically it's put such entries
into the ON SELECT rules of views as well, but those are really quite
vestigial.  The only thing we've used them for is to carry the
view's relid forward to AcquireExecutorLocks (so that we can
re-lock the view to verify it hasn't changed before re-using a plan)
and to carry its relid and permissions data forward to execution-time
permissions checks.  What we can do instead of that is to retain
these fields of the RTE_RELATION RTE for the view even after we
convert it to an RTE_SUBQUERY RTE.  This requires a tiny amount of
extra complication in the planner and AcquireExecutorLocks, but on
the other hand we can get rid of the logic that moves that data from
one place to another.

The principal immediate benefit of doing this, aside from a small
saving in the pg_rewrite data for views, is that these pseudo-RTEs
no longer trigger ruleutils.c's heuristic about qualifying variable
names when the rangetable's length is more than 1.  That results
in quite a number of small simplifications in regression test outputs,
which are all to the good IMO.

Bump catversion because we need to dump a few more fields of
RTE_SUBQUERY RTEs.  While those will always be zeroes anyway in
stored rules (because we'd never populate them until query rewrite)
they are useful for debugging, and it seems like we'd better make
sure to transmit such RTEs accurately in plans sent to parallel
workers.  I don't think the executor actually examines these fields
after startup, but someday it might.

Amit Langote

Discussion: https://postgr.es/m/CA+HiwqEf7gPN4Hn+LoZ4tP2q_Qt7n3vw7-6fJKOf92tSEnX6Gg@mail.gmail.com
This commit is contained in:
Tom Lane
2023-01-11 19:41:02 -05:00
parent 2ff5ca86e8
commit 1b4d280ea1
34 changed files with 774 additions and 890 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
src/backend/optimizer/plan/setrefs.c
View File

@@ -405,13 +405,15 @@ add_rtes_to_flat_rtable(PlannerInfo *root, bool recursing)
*
* At top level, we must add all RTEs so that their indexes in the
* flattened rangetable match up with their original indexes. When
* recursing, we only care about extracting relation RTEs.
* recursing, we only care about extracting relation RTEs (and subquery
* RTEs that were once relation RTEs).
*/
foreach(lc, root->parse->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
if (!recursing || rte->rtekind == RTE_RELATION)
if (!recursing || rte->rtekind == RTE_RELATION ||
(rte->rtekind == RTE_SUBQUERY && OidIsValid(rte->relid)))
add_rte_to_flat_rtable(glob, root->parse->rteperminfos, rte);
}
@@ -501,8 +503,9 @@ flatten_rtes_walker(Node *node, flatten_rtes_walker_context *cxt)
{
RangeTblEntry *rte = (RangeTblEntry *) node;
/* As above, we need only save relation RTEs */
if (rte->rtekind == RTE_RELATION)
/* As above, we need only save relation RTEs and former relations */
if (rte->rtekind == RTE_RELATION ||
(rte->rtekind == RTE_SUBQUERY && OidIsValid(rte->relid)))
add_rte_to_flat_rtable(cxt->glob, cxt->query->rteperminfos, rte);
return false;
}
@@ -560,7 +563,8 @@ add_rte_to_flat_rtable(PlannerGlobal *glob, List *rteperminfos,
glob->finalrtable = lappend(glob->finalrtable, newrte);
/*
* If it's a plain relation RTE, add the table to relationOids.
* If it's a plain relation RTE (or a subquery that was once a view
* reference), add the relation OID to relationOids.
*
* We do this even though the RTE might be unreferenced in the plan tree;
* this would correspond to cases such as views that were expanded, child
@@ -570,7 +574,8 @@ add_rte_to_flat_rtable(PlannerGlobal *glob, List *rteperminfos,
* Note we don't bother to avoid making duplicate list entries. We could,
* but it would probably cost more cycles than it would save.
*/
if (newrte->rtekind == RTE_RELATION)
if (newrte->rtekind == RTE_RELATION ||
(newrte->rtekind == RTE_SUBQUERY && OidIsValid(newrte->relid)))
glob->relationOids = lappend_oid(glob->relationOids, newrte->relid);
/*
@@ -3403,14 +3408,11 @@ extract_query_dependencies_walker(Node *node, PlannerInfo *context)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
if (rte->rtekind == RTE_RELATION)
if (rte->rtekind == RTE_RELATION ||
(rte->rtekind == RTE_SUBQUERY && OidIsValid(rte->relid)) ||
(rte->rtekind == RTE_NAMEDTUPLESTORE && OidIsValid(rte->relid)))
context->glob->relationOids =
lappend_oid(context->glob->relationOids, rte->relid);
else if (rte->rtekind == RTE_NAMEDTUPLESTORE &&
OidIsValid(rte->relid))
context->glob->relationOids =
lappend_oid(context->glob->relationOids,
rte->relid);
}
/* And recurse into the query's subexpressions */