diff options
Diffstat (limited to 'src/backend/rewrite/rewriteSearchCycle.c')
| -rw-r--r-- | src/backend/rewrite/rewriteSearchCycle.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/src/backend/rewrite/rewriteSearchCycle.c b/src/backend/rewrite/rewriteSearchCycle.c index dc408404ebe..58f684cd52e 100644 --- a/src/backend/rewrite/rewriteSearchCycle.c +++ b/src/backend/rewrite/rewriteSearchCycle.c @@ -383,19 +383,32 @@ rewriteSearchAndCycle(CommonTableExpr *cte) newrte->eref = newrte->alias; /* - * Find the reference to our CTE in the range table + * Find the reference to the recursive CTE in the right UNION subquery's + * range table. We expect it to be two levels up from the UNION subquery + * (and must check that to avoid being fooled by sub-WITHs with the same + * CTE name). There will not be more than one such reference, because the + * parser would have rejected that (see checkWellFormedRecursion() in + * parse_cte.c). However, the parser doesn't insist that the reference + * appear in the UNION subquery's topmost range table, so we might fail to + * find it at all. That's an unimplemented case for the moment. */ for (int rti = 1; rti <= list_length(rte2->subquery->rtable); rti++) { RangeTblEntry *e = rt_fetch(rti, rte2->subquery->rtable); - if (e->rtekind == RTE_CTE && strcmp(cte->ctename, e->ctename) == 0) + if (e->rtekind == RTE_CTE && + strcmp(cte->ctename, e->ctename) == 0 && + e->ctelevelsup == 2) { cte_rtindex = rti; break; } } - Assert(cte_rtindex > 0); + if (cte_rtindex <= 0) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("with a SEARCH or CYCLE clause, the recursive reference to WITH query \"%s\" must be at the top level of its right-hand SELECT", + cte->ctename))); newsubquery = copyObject(rte2->subquery); IncrementVarSublevelsUp((Node *) newsubquery, 1, 1); |