From cb3965da10c6451fdb41d5f33706af88393776b0 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 9 Sep 2009 03:32:52 +0000 Subject: [PATCH] Fix bug with WITH RECURSIVE immediately inside WITH RECURSIVE. 99% of the code was already okay with this, but the hack that obtained the output column types of a recursive union in advance of doing real parse analysis of the recursive union forgot to handle the case where there was an inner WITH clause available to the non-recursive term. Best fix seems to be to refactor so that we don't need the "throwaway" parse analysis step at all. Instead, teach the transformSetOperationStmt code to set up the CTE's output column information after it's processed the non-recursive term normally. Per report from David Fetter. --- src/backend/parser/analyze.c | 88 ++++++++++++++++++++++++++++-- src/backend/parser/parse_clause.c | 2 +- src/backend/parser/parse_cte.c | 43 +++++---------- src/backend/parser/parse_expr.c | 2 +- src/include/parser/analyze.h | 3 +- src/include/parser/parse_cte.h | 3 + src/include/parser/parse_node.h | 4 ++ src/test/regress/expected/with.out | 73 +++++++++++++++++++++++++ src/test/regress/sql/with.sql | 15 +++++ 9 files changed, 196 insertions(+), 37 deletions(-) diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c index e81c8e9149..d1563618b8 100644 --- a/src/backend/parser/analyze.c +++ b/src/backend/parser/analyze.c @@ -50,7 +50,9 @@ static Query *transformSelectStmt(ParseState *pstate, SelectStmt *stmt); static Query *transformValuesClause(ParseState *pstate, SelectStmt *stmt); static Query *transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt); static Node *transformSetOperationTree(ParseState *pstate, SelectStmt *stmt, - List **colInfo); + bool isTopLevel, List **colInfo); +static void determineRecursiveColTypes(ParseState *pstate, + Node *larg, List *lcolinfo); static void applyColumnNames(List *dst, List *src); static Query *transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt); static List *transformReturningList(ParseState *pstate, List *returningList); @@ -135,11 +137,14 @@ parse_analyze_varparams(Node *parseTree, const char *sourceText, * Entry point for recursively analyzing a sub-statement. */ Query * -parse_sub_analyze(Node *parseTree, ParseState *parentParseState) +parse_sub_analyze(Node *parseTree, ParseState *parentParseState, + CommonTableExpr *parentCTE) { ParseState *pstate = make_parsestate(parentParseState); Query *query; + pstate->p_parent_cte = parentCTE; + query = transformStmt(pstate, parseTree); free_parsestate(pstate); @@ -1199,6 +1204,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt) * Recursively transform the components of the tree. */ sostmt = (SetOperationStmt *) transformSetOperationTree(pstate, stmt, + true, &socolinfo); Assert(sostmt && IsA(sostmt, SetOperationStmt)); qry->setOperations = (Node *) sostmt; @@ -1359,7 +1365,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt) */ static Node * transformSetOperationTree(ParseState *pstate, SelectStmt *stmt, - List **colInfo) + bool isTopLevel, List **colInfo) { bool isLeaf; @@ -1418,7 +1424,7 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt, * of this sub-query, because they are not in the toplevel pstate's * namespace list. */ - selectQuery = parse_sub_analyze((Node *) stmt, pstate); + selectQuery = parse_sub_analyze((Node *) stmt, pstate, NULL); /* * Check for bogus references to Vars on the current query level (but @@ -1485,11 +1491,28 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt, op->all = stmt->all; /* - * Recursively transform the child nodes. + * Recursively transform the left child node. */ op->larg = transformSetOperationTree(pstate, stmt->larg, + false, &lcolinfo); + + /* + * If we are processing a recursive union query, now is the time + * to examine the non-recursive term's output columns and mark the + * containing CTE as having those result columns. We should do this + * only at the topmost setop of the CTE, of course. + */ + if (isTopLevel && + pstate->p_parent_cte && + pstate->p_parent_cte->cterecursive) + determineRecursiveColTypes(pstate, op->larg, lcolinfo); + + /* + * Recursively transform the right child node. + */ op->rarg = transformSetOperationTree(pstate, stmt->rarg, + false, &rcolinfo); /* @@ -1584,6 +1607,61 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt, } } +/* + * Process the outputs of the non-recursive term of a recursive union + * to set up the parent CTE's columns + */ +static void +determineRecursiveColTypes(ParseState *pstate, Node *larg, List *lcolinfo) +{ + Node *node; + int leftmostRTI; + Query *leftmostQuery; + List *targetList; + ListCell *left_tlist; + ListCell *lci; + int next_resno; + + /* + * Find leftmost leaf SELECT + */ + node = larg; + while (node && IsA(node, SetOperationStmt)) + node = ((SetOperationStmt *) node)->larg; + Assert(node && IsA(node, RangeTblRef)); + leftmostRTI = ((RangeTblRef *) node)->rtindex; + leftmostQuery = rt_fetch(leftmostRTI, pstate->p_rtable)->subquery; + Assert(leftmostQuery != NULL); + + /* + * Generate dummy targetlist using column names of leftmost select + * and dummy result expressions of the non-recursive term. + */ + targetList = NIL; + left_tlist = list_head(leftmostQuery->targetList); + next_resno = 1; + + foreach(lci, lcolinfo) + { + Expr *lcolexpr = (Expr *) lfirst(lci); + TargetEntry *lefttle = (TargetEntry *) lfirst(left_tlist); + char *colName; + TargetEntry *tle; + + Assert(!lefttle->resjunk); + colName = pstrdup(lefttle->resname); + tle = makeTargetEntry(lcolexpr, + next_resno++, + colName, + false); + targetList = lappend(targetList, tle); + left_tlist = lnext(left_tlist); + } + + /* Now build CTE's output column info using dummy targetlist */ + analyzeCTETargetList(pstate, pstate->p_parent_cte, targetList); +} + /* * Attach column names from a ColumnDef list to a TargetEntry list * (for CREATE TABLE AS) diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c index 5cc44e51e5..8528231309 100644 --- a/src/backend/parser/parse_clause.c +++ b/src/backend/parser/parse_clause.c @@ -479,7 +479,7 @@ transformRangeSubselect(ParseState *pstate, RangeSubselect *r) /* * Analyze and transform the subquery. */ - query = parse_sub_analyze(r->subquery, pstate); + query = parse_sub_analyze(r->subquery, pstate, NULL); /* * Check that we got something reasonable. Many of these conditions are diff --git a/src/backend/parser/parse_cte.c b/src/backend/parser/parse_cte.c index 988e8eb709..19bfb8e781 100644 --- a/src/backend/parser/parse_cte.c +++ b/src/backend/parser/parse_cte.c @@ -58,8 +58,6 @@ typedef struct CteItem { CommonTableExpr *cte; /* One CTE to examine */ int id; /* Its ID number for dependencies */ - Node *non_recursive_term; /* Its nonrecursive part, if - * identified */ Bitmapset *depends_on; /* CTEs depended on (not including self) */ } CteItem; @@ -80,7 +78,6 @@ typedef struct CteState static void analyzeCTE(ParseState *pstate, CommonTableExpr *cte); -static void analyzeCTETargetList(ParseState *pstate, CommonTableExpr *cte, List *tlist); /* Dependency processing functions */ static void makeDependencyGraph(CteState *cstate); @@ -191,25 +188,6 @@ transformWithClause(ParseState *pstate, WithClause *withClause) { CommonTableExpr *cte = cstate.items[i].cte; - /* - * If it's recursive, we have to do a throwaway parse analysis of - * the non-recursive term in order to determine the set of output - * columns for the recursive CTE. - */ - if (cte->cterecursive) - { - Node *nrt; - Query *nrq; - - if (!cstate.items[i].non_recursive_term) - elog(ERROR, "could not find non-recursive term for %s", - cte->ctename); - /* copy the term to be sure we don't modify original query */ - nrt = copyObject(cstate.items[i].non_recursive_term); - nrq = parse_sub_analyze(nrt, pstate); - analyzeCTETargetList(pstate, cte, nrq->targetList); - } - analyzeCTE(pstate, cte); } } @@ -251,7 +229,7 @@ analyzeCTE(ParseState *pstate, CommonTableExpr *cte) /* Analysis not done already */ Assert(IsA(cte->ctequery, SelectStmt)); - query = parse_sub_analyze(cte->ctequery, pstate); + query = parse_sub_analyze(cte->ctequery, pstate, cte); cte->ctequery = (Node *) query; /* @@ -325,14 +303,26 @@ analyzeCTE(ParseState *pstate, CommonTableExpr *cte) /* * Compute derived fields of a CTE, given the transformed output targetlist + * + * For a nonrecursive CTE, this is called after transforming the CTE's query. + * For a recursive CTE, we call it after transforming the non-recursive term, + * and pass the targetlist emitted by the non-recursive term only. + * + * Note: in the recursive case, the passed pstate is actually the one being + * used to analyze the CTE's query, so it is one level lower down than in + * the nonrecursive case. This doesn't matter since we only use it for + * error message context anyway. */ -static void +void analyzeCTETargetList(ParseState *pstate, CommonTableExpr *cte, List *tlist) { int numaliases; int varattno; ListCell *tlistitem; + /* Not done already ... */ + Assert(cte->ctecolnames == NIL); + /* * We need to determine column names and types. The alias column names * override anything coming from the query itself. (Note: the SQL spec @@ -668,11 +658,6 @@ checkWellFormedRecursion(CteState *cstate) errmsg("FOR UPDATE/SHARE in a recursive query is not implemented"), parser_errposition(cstate->pstate, exprLocation((Node *) stmt->lockingClause)))); - - /* - * Save non_recursive_term. - */ - cstate->items[i].non_recursive_term = (Node *) stmt->larg; } } diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index 428adbdbdf..666b666d04 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -1251,7 +1251,7 @@ transformSubLink(ParseState *pstate, SubLink *sublink) return result; pstate->p_hasSubLinks = true; - qtree = parse_sub_analyze(sublink->subselect, pstate); + qtree = parse_sub_analyze(sublink->subselect, pstate, NULL); /* * Check that we got something reasonable. Many of these conditions are diff --git a/src/include/parser/analyze.h b/src/include/parser/analyze.h index ba712d523b..8a57df5188 100644 --- a/src/include/parser/analyze.h +++ b/src/include/parser/analyze.h @@ -22,7 +22,8 @@ extern Query *parse_analyze(Node *parseTree, const char *sourceText, extern Query *parse_analyze_varparams(Node *parseTree, const char *sourceText, Oid **paramTypes, int *numParams); -extern Query *parse_sub_analyze(Node *parseTree, ParseState *parentParseState); +extern Query *parse_sub_analyze(Node *parseTree, ParseState *parentParseState, + CommonTableExpr *parentCTE); extern Query *transformStmt(ParseState *pstate, Node *parseTree); extern bool analyze_requires_snapshot(Node *parseTree); diff --git a/src/include/parser/parse_cte.h b/src/include/parser/parse_cte.h index 59b8e9f05c..c74c4a59dd 100644 --- a/src/include/parser/parse_cte.h +++ b/src/include/parser/parse_cte.h @@ -18,4 +18,7 @@ extern List *transformWithClause(ParseState *pstate, WithClause *withClause); +extern void analyzeCTETargetList(ParseState *pstate, CommonTableExpr *cte, + List *tlist); + #endif /* PARSE_CTE_H */ diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h index b4e5448f6d..7a75c911eb 100644 --- a/src/include/parser/parse_node.h +++ b/src/include/parser/parse_node.h @@ -61,6 +61,9 @@ * p_future_ctes: list of CommonTableExprs (WITH items) that are not yet * visible due to scope rules. This is used to help improve error messages. * + * p_parent_cte: CommonTableExpr that immediately contains the current query, + * if any. + * * p_windowdefs: list of WindowDefs representing WINDOW and OVER clauses. * We collect these while transforming expressions and then transform them * afterwards (so that any resjunk tlist items needed for the sort/group @@ -88,6 +91,7 @@ typedef struct ParseState List *p_varnamespace; /* current namespace for columns */ List *p_ctenamespace; /* current namespace for common table exprs */ List *p_future_ctes; /* common table exprs not yet in namespace */ + CommonTableExpr *p_parent_cte; /* this query's containing CTE */ List *p_windowdefs; /* raw representations of window clauses */ Oid *p_paramtypes; /* OIDs of types for $n parameter symbols */ int p_numparams; /* allocated size of p_paramtypes[] */ diff --git a/src/test/regress/expected/with.out b/src/test/regress/expected/with.out index 98003ebe6c..a3e94e93d4 100644 --- a/src/test/regress/expected/with.out +++ b/src/test/regress/expected/with.out @@ -953,3 +953,76 @@ from int4_tbl; -2147483647 (5 rows) +-- +-- test for nested-recursive-WITH bug +-- +WITH RECURSIVE t(j) AS ( + WITH RECURSIVE s(i) AS ( + VALUES (1) + UNION ALL + SELECT i+1 FROM s WHERE i < 10 + ) + SELECT i FROM s + UNION ALL + SELECT j+1 FROM t WHERE j < 10 +) +SELECT * FROM t; + j +---- + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 5 + 6 + 7 + 8 + 9 + 10 + 6 + 7 + 8 + 9 + 10 + 7 + 8 + 9 + 10 + 8 + 9 + 10 + 9 + 10 + 10 +(55 rows) + diff --git a/src/test/regress/sql/with.sql b/src/test/regress/sql/with.sql index 6eaa168d96..2cbaa42492 100644 --- a/src/test/regress/sql/with.sql +++ b/src/test/regress/sql/with.sql @@ -485,3 +485,18 @@ from int4_tbl; select ( with cte(foo) as ( values(f1) ) values((select foo from cte)) ) from int4_tbl; + +-- +-- test for nested-recursive-WITH bug +-- +WITH RECURSIVE t(j) AS ( + WITH RECURSIVE s(i) AS ( + VALUES (1) + UNION ALL + SELECT i+1 FROM s WHERE i < 10 + ) + SELECT i FROM s + UNION ALL + SELECT j+1 FROM t WHERE j < 10 +) +SELECT * FROM t; -- 2.30.2