diff options
Diffstat (limited to 'src/backend')
| -rw-r--r-- | src/backend/rewrite/rewriteHandler.c | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c index d4c32e308fc..768fb22dcf7 100644 --- a/src/backend/rewrite/rewriteHandler.c +++ b/src/backend/rewrite/rewriteHandler.c @@ -1893,6 +1893,9 @@ fireRules(Query *parsetree, * * Caller should have verified that the relation is a view, and therefore * we should find an ON SELECT action. + * + * Note that the pointer returned is into the relcache and therefore must + * be treated as read-only to the caller and not modified or scribbled on. */ static Query * get_view_query(Relation view) @@ -2377,8 +2380,14 @@ rewriteTargetView(Query *parsetree, Relation view) /* * If we get here, view_is_auto_updatable() has verified that the view * contains a single base relation. + * + * Get the Query from the view's ON SELECT rule. We're going to munge the + * Query to change the view's base relation into the target relation, + * along with various other changes along the way, so we need to make a + * copy of it (get_view_query() returns a pointer into the relcache, so we + * have to treat it as read-only). */ - viewquery = get_view_query(view); + viewquery = copyObject(get_view_query(view)); Assert(list_length(viewquery->jointree->fromlist) == 1); rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist); @@ -2427,7 +2436,7 @@ rewriteTargetView(Query *parsetree, Relation view) * outer query. Perhaps someday we should refactor things enough so that * we can share code with the planner.) */ - new_rte = (RangeTblEntry *) copyObject(base_rte); + new_rte = (RangeTblEntry *) base_rte; parsetree->rtable = lappend(parsetree->rtable, new_rte); new_rt_index = list_length(parsetree->rtable); @@ -2439,14 +2448,14 @@ rewriteTargetView(Query *parsetree, Relation view) new_rte->inh = false; /* - * Make a copy of the view's targetlist, adjusting its Vars to reference - * the new target RTE, ie make their varnos be new_rt_index instead of - * base_rt_index. There can be no Vars for other rels in the tlist, so - * this is sufficient to pull up the tlist expressions for use in the - * outer query. The tlist will provide the replacement expressions used - * by ReplaceVarsFromTargetList below. + * Adjust the view's targetlist Vars to reference the new target RTE, ie + * make their varnos be new_rt_index instead of base_rt_index. There can + * be no Vars for other rels in the tlist, so this is sufficient to pull + * up the tlist expressions for use in the outer query. The tlist will + * provide the replacement expressions used by ReplaceVarsFromTargetList + * below. */ - view_targetlist = copyObject(viewquery->targetList); + view_targetlist = viewquery->targetList; ChangeVarNodes((Node *) view_targetlist, base_rt_index, @@ -2581,7 +2590,7 @@ rewriteTargetView(Query *parsetree, Relation view) if (parsetree->commandType != CMD_INSERT && viewquery->jointree->quals != NULL) { - Node *viewqual = (Node *) copyObject(viewquery->jointree->quals); + Node *viewqual = (Node *) viewquery->jointree->quals; ChangeVarNodes(viewqual, base_rt_index, new_rt_index, 0); AddQual(parsetree, (Node *) viewqual); |