/*------------------------------------------------------------------------- * * prepunion.c * Routines to plan set-operation queries. The filename is a leftover * from a time when only UNIONs were implemented. * * There are two code paths in the planner for set-operation queries. * If a subquery consists entirely of simple UNION ALL operations, it * is converted into an "append relation". Otherwise, it is handled * by the general code in this module (plan_set_operations and its * subroutines). There is some support code here for the append-relation * case, but most of the heavy lifting for that is done elsewhere, * notably in prepjointree.c and allpaths.c. * * There is also some code here to support planning of queries that use * inheritance (SELECT FROM foo*). Inheritance trees are converted into * append relations, and thenceforth share code with the UNION ALL case. * * * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.138 2007/02/19 07:03:30 tgl Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/heapam.h" #include "catalog/namespace.h" #include "catalog/pg_type.h" #include "nodes/makefuncs.h" #include "optimizer/clauses.h" #include "optimizer/plancat.h" #include "optimizer/planmain.h" #include "optimizer/planner.h" #include "optimizer/prep.h" #include "optimizer/tlist.h" #include "parser/parse_clause.h" #include "parser/parse_coerce.h" #include "parser/parse_expr.h" #include "parser/parsetree.h" #include "utils/lsyscache.h" static Plan *recurse_set_operations(Node *setOp, PlannerInfo *root, double tuple_fraction, List *colTypes, bool junkOK, int flag, List *refnames_tlist, List **sortClauses); static Plan *generate_union_plan(SetOperationStmt *op, PlannerInfo *root, double tuple_fraction, List *refnames_tlist, List **sortClauses); static Plan *generate_nonunion_plan(SetOperationStmt *op, PlannerInfo *root, List *refnames_tlist, List **sortClauses); static List *recurse_union_children(Node *setOp, PlannerInfo *root, double tuple_fraction, SetOperationStmt *top_union, List *refnames_tlist); static List *generate_setop_tlist(List *colTypes, int flag, Index varno, bool hack_constants, List *input_tlist, List *refnames_tlist); static List *generate_append_tlist(List *colTypes, bool flag, List *input_plans, List *refnames_tlist); static void expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti); static void make_inh_translation_lists(Relation oldrelation, Relation newrelation, Index newvarno, List **col_mappings, List **translated_vars); static Node *adjust_appendrel_attrs_mutator(Node *node, AppendRelInfo *context); static Relids adjust_relid_set(Relids relids, Index oldrelid, Index newrelid); static List *adjust_inherited_tlist(List *tlist, AppendRelInfo *context); /* * plan_set_operations * * Plans the queries for a tree of set operations (UNION/INTERSECT/EXCEPT) * * This routine only deals with the setOperations tree of the given query. * Any top-level ORDER BY requested in root->parse->sortClause will be added * when we return to grouping_planner. * * tuple_fraction is the fraction of tuples we expect will be retrieved. * tuple_fraction is interpreted as for grouping_planner(); in particular, * zero means "all the tuples will be fetched". Any LIMIT present at the * top level has already been factored into tuple_fraction. * * *sortClauses is an output argument: it is set to a list of SortClauses * representing the result ordering of the topmost set operation. */ Plan * plan_set_operations(PlannerInfo *root, double tuple_fraction, List **sortClauses) { Query *parse = root->parse; SetOperationStmt *topop = (SetOperationStmt *) parse->setOperations; Node *node; Query *leftmostQuery; Assert(topop && IsA(topop, SetOperationStmt)); /* check for unsupported stuff */ Assert(parse->utilityStmt == NULL); Assert(parse->jointree->fromlist == NIL); Assert(parse->jointree->quals == NULL); Assert(parse->groupClause == NIL); Assert(parse->havingQual == NULL); Assert(parse->distinctClause == NIL); /* * Find the leftmost component Query. We need to use its column names for * all generated tlists (else SELECT INTO won't work right). */ node = topop->larg; while (node && IsA(node, SetOperationStmt)) node = ((SetOperationStmt *) node)->larg; Assert(node && IsA(node, RangeTblRef)); leftmostQuery = rt_fetch(((RangeTblRef *) node)->rtindex, parse->rtable)->subquery; Assert(leftmostQuery != NULL); /* * Recurse on setOperations tree to generate plans for set ops. The final * output plan should have just the column types shown as the output from * the top-level node, plus possibly resjunk working columns (we can rely * on upper-level nodes to deal with that). */ return recurse_set_operations((Node *) topop, root, tuple_fraction, topop->colTypes, true, -1, leftmostQuery->targetList, sortClauses); } /* * recurse_set_operations * Recursively handle one step in a tree of set operations * * tuple_fraction: fraction of tuples we expect to retrieve from node * colTypes: list of type OIDs of expected output columns * junkOK: if true, child resjunk columns may be left in the result * flag: if >= 0, add a resjunk output column indicating value of flag * refnames_tlist: targetlist to take column names from * *sortClauses: receives list of SortClauses for result plan, if any * * We don't have to care about typmods here: the only allowed difference * between set-op input and output typmods is input is a specific typmod * and output is -1, and that does not require a coercion. */ static Plan * recurse_set_operations(Node *setOp, PlannerInfo *root, double tuple_fraction, List *colTypes, bool junkOK, int flag, List *refnames_tlist, List **sortClauses) { if (IsA(setOp, RangeTblRef)) { RangeTblRef *rtr = (RangeTblRef *) setOp; RangeTblEntry *rte = rt_fetch(rtr->rtindex, root->parse->rtable); Query *subquery = rte->subquery; Plan *subplan, *plan; Assert(subquery != NULL); /* * Generate plan for primitive subquery */ subplan = subquery_planner(root->glob, subquery, root->query_level + 1, tuple_fraction, NULL); /* * Add a SubqueryScan with the caller-requested targetlist */ plan = (Plan *) make_subqueryscan(generate_setop_tlist(colTypes, flag, rtr->rtindex, true, subplan->targetlist, refnames_tlist), NIL, rtr->rtindex, subplan); /* * We don't bother to determine the subquery's output ordering since * it won't be reflected in the set-op result anyhow. */ *sortClauses = NIL; return plan; } else if (IsA(setOp, SetOperationStmt)) { SetOperationStmt *op = (SetOperationStmt *) setOp; Plan *plan; /* UNIONs are much different from INTERSECT/EXCEPT */ if (op->op == SETOP_UNION) plan = generate_union_plan(op, root, tuple_fraction, refnames_tlist, sortClauses); else plan = generate_nonunion_plan(op, root, refnames_tlist, sortClauses); /* * If necessary, add a Result node to project the caller-requested * output columns. * * XXX you don't really want to know about this: setrefs.c will apply * replace_vars_with_subplan_refs() to the Result node's tlist. This * would fail if the Vars generated by generate_setop_tlist() were not * exactly equal() to the corresponding tlist entries of the subplan. * However, since the subplan was generated by generate_union_plan() * or generate_nonunion_plan(), and hence its tlist was generated by * generate_append_tlist(), this will work. We just tell * generate_setop_tlist() to use varno 0. */ if (flag >= 0 || !tlist_same_datatypes(plan->targetlist, colTypes, junkOK)) { plan = (Plan *) make_result(generate_setop_tlist(colTypes, flag, 0, false, plan->targetlist, refnames_tlist), NULL, plan); } return plan; } else { elog(ERROR, "unrecognized node type: %d", (int) nodeTag(setOp)); return NULL; /* keep compiler quiet */ } } /* * Generate plan for a UNION or UNION ALL node */ static Plan * generate_union_plan(SetOperationStmt *op, PlannerInfo *root, double tuple_fraction, List *refnames_tlist, List **sortClauses) { List *planlist; List *tlist; Plan *plan; /* * If plain UNION, tell children to fetch all tuples. * * Note: in UNION ALL, we pass the top-level tuple_fraction unmodified to * each arm of the UNION ALL. One could make a case for reducing the * tuple fraction for later arms (discounting by the expected size of the * earlier arms' results) but it seems not worth the trouble. The normal * case where tuple_fraction isn't already zero is a LIMIT at top level, * and passing it down as-is is usually enough to get the desired result * of preferring fast-start plans. */ if (!op->all) tuple_fraction = 0.0; /* * If any of my children are identical UNION nodes (same op, all-flag, and * colTypes) then they can be merged into this node so that we generate * only one Append and Sort for the lot. Recurse to find such nodes and * compute their children's plans. */ planlist = list_concat(recurse_union_children(op->larg, root, tuple_fraction, op, refnames_tlist), recurse_union_children(op->rarg, root, tuple_fraction, op, refnames_tlist)); /* * Generate tlist for Append plan node. * * The tlist for an Append plan isn't important as far as the Append is * concerned, but we must make it look real anyway for the benefit of the * next plan level up. */ tlist = generate_append_tlist(op->colTypes, false, planlist, refnames_tlist); /* * Append the child results together. */ plan = (Plan *) make_append(planlist, false, tlist); /* * For UNION ALL, we just need the Append plan. For UNION, need to add * Sort and Unique nodes to produce unique output. */ if (!op->all) { List *sortList; sortList = addAllTargetsToSortList(NULL, NIL, tlist, false); if (sortList) { plan = (Plan *) make_sort_from_sortclauses(root, sortList, plan); plan = (Plan *) make_unique(plan, sortList); } *sortClauses = sortList; } else *sortClauses = NIL; return plan; } /* * Generate plan for an INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL node */ static Plan * generate_nonunion_plan(SetOperationStmt *op, PlannerInfo *root, List *refnames_tlist, List **sortClauses) { Plan *lplan, *rplan, *plan; List *tlist, *sortList, *planlist, *child_sortclauses; SetOpCmd cmd; /* Recurse on children, ensuring their outputs are marked */ lplan = recurse_set_operations(op->larg, root, 0.0 /* all tuples needed */ , op->colTypes, false, 0, refnames_tlist, &child_sortclauses); rplan = recurse_set_operations(op->rarg, root, 0.0 /* all tuples needed */ , op->colTypes, false, 1, refnames_tlist, &child_sortclauses); planlist = list_make2(lplan, rplan); /* * Generate tlist for Append plan node. * * The tlist for an Append plan isn't important as far as the Append is * concerned, but we must make it look real anyway for the benefit of the * next plan level up. In fact, it has to be real enough that the flag * column is shown as a variable not a constant, else setrefs.c will get * confused. */ tlist = generate_append_tlist(op->colTypes, true, planlist, refnames_tlist); /* * Append the child results together. */ plan = (Plan *) make_append(planlist, false, tlist); /* * Sort the child results, then add a SetOp plan node to generate the * correct output. */ sortList = addAllTargetsToSortList(NULL, NIL, tlist, false); if (sortList == NIL) /* nothing to sort on? */ { *sortClauses = NIL; return plan; } plan = (Plan *) make_sort_from_sortclauses(root, sortList, plan); switch (op->op) { case SETOP_INTERSECT: cmd = op->all ? SETOPCMD_INTERSECT_ALL : SETOPCMD_INTERSECT; break; case SETOP_EXCEPT: cmd = op->all ? SETOPCMD_EXCEPT_ALL : SETOPCMD_EXCEPT; break; default: elog(ERROR, "unrecognized set op: %d", (int) op->op); cmd = SETOPCMD_INTERSECT; /* keep compiler quiet */ break; } plan = (Plan *) make_setop(cmd, plan, sortList, list_length(op->colTypes) + 1); *sortClauses = sortList; return plan; } /* * Pull up children of a UNION node that are identically-propertied UNIONs. * * NOTE: we can also pull a UNION ALL up into a UNION, since the distinct * output rows will be lost anyway. */ static List * recurse_union_children(Node *setOp, PlannerInfo *root, double tuple_fraction, SetOperationStmt *top_union, List *refnames_tlist) { List *child_sortclauses; if (IsA(setOp, SetOperationStmt)) { SetOperationStmt *op = (SetOperationStmt *) setOp; if (op->op == top_union->op && (op->all == top_union->all || op->all) && equal(op->colTypes, top_union->colTypes)) { /* Same UNION, so fold children into parent's subplan list */ return list_concat(recurse_union_children(op->larg, root, tuple_fraction, top_union, refnames_tlist), recurse_union_children(op->rarg, root, tuple_fraction, top_union, refnames_tlist)); } } /* * Not same, so plan this child separately. * * Note we disallow any resjunk columns in child results. This is * necessary since the Append node that implements the union won't do any * projection, and upper levels will get confused if some of our output * tuples have junk and some don't. This case only arises when we have an * EXCEPT or INTERSECT as child, else there won't be resjunk anyway. */ return list_make1(recurse_set_operations(setOp, root, tuple_fraction, top_union->colTypes, false, -1, refnames_tlist, &child_sortclauses)); } /* * Generate targetlist for a set-operation plan node * * colTypes: column datatypes for non-junk columns * flag: -1 if no flag column needed, 0 or 1 to create a const flag column * varno: varno to use in generated Vars * hack_constants: true to copy up constants (see comments in code) * input_tlist: targetlist of this node's input node * refnames_tlist: targetlist to take column names from */ static List * generate_setop_tlist(List *colTypes, int flag, Index varno, bool hack_constants, List *input_tlist, List *refnames_tlist) { List *tlist = NIL; int resno = 1; ListCell *i, *j, *k; TargetEntry *tle; Node *expr; j = list_head(input_tlist); k = list_head(refnames_tlist); foreach(i, colTypes) { Oid colType = lfirst_oid(i); TargetEntry *inputtle = (TargetEntry *) lfirst(j); TargetEntry *reftle = (TargetEntry *) lfirst(k); Assert(inputtle->resno == resno); Assert(reftle->resno == resno); Assert(!inputtle->resjunk); Assert(!reftle->resjunk); /* * Generate columns referencing input columns and having appropriate * data types and column names. Insert datatype coercions where * necessary. * * HACK: constants in the input's targetlist are copied up as-is * rather than being referenced as subquery outputs. This is mainly * to ensure that when we try to coerce them to the output column's * datatype, the right things happen for UNKNOWN constants. But do * this only at the first level of subquery-scan plans; we don't want * phony constants appearing in the output tlists of upper-level * nodes! */ if (hack_constants && inputtle->expr && IsA(inputtle->expr, Const)) expr = (Node *) inputtle->expr; else expr = (Node *) makeVar(varno, inputtle->resno, exprType((Node *) inputtle->expr), exprTypmod((Node *) inputtle->expr), 0); if (exprType(expr) != colType) { expr = coerce_to_common_type(NULL, /* no UNKNOWNs here */ expr, colType, "UNION/INTERSECT/EXCEPT"); } tle = makeTargetEntry((Expr *) expr, (AttrNumber) resno++, pstrdup(reftle->resname), false); tlist = lappend(tlist, tle); j = lnext(j); k = lnext(k); } if (flag >= 0) { /* Add a resjunk flag column */ /* flag value is the given constant */ expr = (Node *) makeConst(INT4OID, sizeof(int4), Int32GetDatum(flag), false, true); tle = makeTargetEntry((Expr *) expr, (AttrNumber) resno++, pstrdup("flag"), true); tlist = lappend(tlist, tle); } return tlist; } /* * Generate targetlist for a set-operation Append node * * colTypes: column datatypes for non-junk columns * flag: true to create a flag column copied up from subplans * input_plans: list of sub-plans of the Append * refnames_tlist: targetlist to take column names from * * The entries in the Append's targetlist should always be simple Vars; * we just have to make sure they have the right datatypes and typmods. * The Vars are always generated with varno 0. */ static List * generate_append_tlist(List *colTypes, bool flag, List *input_plans, List *refnames_tlist) { List *tlist = NIL; int resno = 1; ListCell *curColType; ListCell *ref_tl_item; int colindex; TargetEntry *tle; Node *expr; ListCell *planl; int32 *colTypmods; /* * First extract typmods to use. * * If the inputs all agree on type and typmod of a particular column, use * that typmod; else use -1. */ colTypmods = (int32 *) palloc(list_length(colTypes) * sizeof(int32)); foreach(planl, input_plans) { Plan *subplan = (Plan *) lfirst(planl); ListCell *subtlist; curColType = list_head(colTypes); colindex = 0; foreach(subtlist, subplan->targetlist) { TargetEntry *subtle = (TargetEntry *) lfirst(subtlist); if (subtle->resjunk) continue; Assert(curColType != NULL); if (exprType((Node *) subtle->expr) == lfirst_oid(curColType)) { /* If first subplan, copy the typmod; else compare */ int32 subtypmod = exprTypmod((Node *) subtle->expr); if (planl == list_head(input_plans)) colTypmods[colindex] = subtypmod; else if (subtypmod != colTypmods[colindex]) colTypmods[colindex] = -1; } else { /* types disagree, so force typmod to -1 */ colTypmods[colindex] = -1; } curColType = lnext(curColType); colindex++; } Assert(curColType == NULL); } /* * Now we can build the tlist for the Append. */ colindex = 0; forboth(curColType, colTypes, ref_tl_item, refnames_tlist) { Oid colType = lfirst_oid(curColType); int32 colTypmod = colTypmods[colindex++]; TargetEntry *reftle = (TargetEntry *) lfirst(ref_tl_item); Assert(reftle->resno == resno); Assert(!reftle->resjunk); expr = (Node *) makeVar(0, resno, colType, colTypmod, 0); tle = makeTargetEntry((Expr *) expr, (AttrNumber) resno++, pstrdup(reftle->resname), false); tlist = lappend(tlist, tle); } if (flag) { /* Add a resjunk flag column */ /* flag value is shown as copied up from subplan */ expr = (Node *) makeVar(0, resno, INT4OID, -1, 0); tle = makeTargetEntry((Expr *) expr, (AttrNumber) resno++, pstrdup("flag"), true); tlist = lappend(tlist, tle); } pfree(colTypmods); return tlist; } /* * find_all_inheritors - * Returns a list of relation OIDs including the given rel plus * all relations that inherit from it, directly or indirectly. */ List * find_all_inheritors(Oid parentrel) { List *rels_list; ListCell *l; /* * We build a list starting with the given rel and adding all direct and * indirect children. We can use a single list as both the record of * already-found rels and the agenda of rels yet to be scanned for more * children. This is a bit tricky but works because the foreach() macro * doesn't fetch the next list element until the bottom of the loop. */ rels_list = list_make1_oid(parentrel); foreach(l, rels_list) { Oid currentrel = lfirst_oid(l); List *currentchildren; /* Get the direct children of this rel */ currentchildren = find_inheritance_children(currentrel); /* * Add to the queue only those children not already seen. This avoids * making duplicate entries in case of multiple inheritance paths from * the same parent. (It'll also keep us from getting into an infinite * loop, though theoretically there can't be any cycles in the * inheritance graph anyway.) */ rels_list = list_concat_unique_oid(rels_list, currentchildren); } return rels_list; } /* * expand_inherited_tables * Expand each rangetable entry that represents an inheritance set * into an "append relation". At the conclusion of this process, * the "inh" flag is set in all and only those RTEs that are append * relation parents. */ void expand_inherited_tables(PlannerInfo *root) { Index nrtes; Index rti; ListCell *rl; /* * expand_inherited_rtentry may add RTEs to parse->rtable; there is no * need to scan them since they can't have inh=true. So just scan as far * as the original end of the rtable list. */ nrtes = list_length(root->parse->rtable); rl = list_head(root->parse->rtable); for (rti = 1; rti <= nrtes; rti++) { RangeTblEntry *rte = (RangeTblEntry *) lfirst(rl); expand_inherited_rtentry(root, rte, rti); rl = lnext(rl); } } /* * expand_inherited_rtentry * Check whether a rangetable entry represents an inheritance set. * If so, add entries for all the child tables to the query's * rangetable, and build AppendRelInfo nodes for all the child tables * and add them to root->append_rel_list. If not, clear the entry's * "inh" flag to prevent later code from looking for AppendRelInfos. * * Note that the original RTE is considered to represent the whole * inheritance set. The first of the generated RTEs is an RTE for the same * table, but with inh = false, to represent the parent table in its role * as a simple member of the inheritance set. * * A childless table is never considered to be an inheritance set; therefore * a parent RTE must always have at least two associated AppendRelInfos. */ static void expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti) { Query *parse = root->parse; Oid parentOID; Relation oldrelation; LOCKMODE lockmode; List *inhOIDs; List *appinfos; ListCell *l; /* Does RT entry allow inheritance? */ if (!rte->inh) return; /* Ignore any already-expanded UNION ALL nodes */ if (rte->rtekind != RTE_RELATION) { Assert(rte->rtekind == RTE_SUBQUERY); return; } /* Fast path for common case of childless table */ parentOID = rte->relid; if (!has_subclass(parentOID)) { /* Clear flag before returning */ rte->inh = false; return; } /* Scan for all members of inheritance set */ inhOIDs = find_all_inheritors(parentOID); /* * Check that there's at least one descendant, else treat as no-child * case. This could happen despite above has_subclass() check, if table * once had a child but no longer does. */ if (list_length(inhOIDs) < 2) { /* Clear flag before returning */ rte->inh = false; return; } /* * Must open the parent relation to examine its tupdesc. We need not lock * it since the rewriter already obtained at least AccessShareLock on each * relation used in the query. */ oldrelation = heap_open(parentOID, NoLock); /* * However, for each child relation we add to the query, we must obtain an * appropriate lock, because this will be the first use of those relations * in the parse/rewrite/plan pipeline. * * If the parent relation is the query's result relation, then we need * RowExclusiveLock. Otherwise, check to see if the relation is accessed * FOR UPDATE/SHARE or not. We can't just grab AccessShareLock because * then the executor would be trying to upgrade the lock, leading to * possible deadlocks. (This code should match the parser and rewriter.) */ if (rti == parse->resultRelation) lockmode = RowExclusiveLock; else if (get_rowmark(parse, rti)) lockmode = RowShareLock; else lockmode = AccessShareLock; /* Scan the inheritance set and expand it */ appinfos = NIL; foreach(l, inhOIDs) { Oid childOID = lfirst_oid(l); Relation newrelation; RangeTblEntry *childrte; Index childRTindex; AppendRelInfo *appinfo; /* * It is possible that the parent table has children that are temp * tables of other backends. We cannot safely access such tables * (because of buffering issues), and the best thing to do seems to be * to silently ignore them. */ if (childOID != parentOID && isOtherTempNamespace(get_rel_namespace(childOID))) continue; /* Open rel, acquire the appropriate lock type */ if (childOID != parentOID) newrelation = heap_open(childOID, lockmode); else newrelation = oldrelation; /* * Build an RTE for the child, and attach to query's rangetable list. * We copy most fields of the parent's RTE, but replace relation OID, * and set inh = false. */ childrte = copyObject(rte); childrte->relid = childOID; childrte->inh = false; parse->rtable = lappend(parse->rtable, childrte); childRTindex = list_length(parse->rtable); /* * Build an AppendRelInfo for this parent and child. */ appinfo = makeNode(AppendRelInfo); appinfo->parent_relid = rti; appinfo->child_relid = childRTindex; appinfo->parent_reltype = oldrelation->rd_rel->reltype; appinfo->child_reltype = newrelation->rd_rel->reltype; make_inh_translation_lists(oldrelation, newrelation, childRTindex, &appinfo->col_mappings, &appinfo->translated_vars); appinfo->parent_reloid = parentOID; appinfos = lappend(appinfos, appinfo); /* Close child relations, but keep locks */ if (childOID != parentOID) heap_close(newrelation, NoLock); } heap_close(oldrelation, NoLock); /* * If all the children were temp tables, pretend it's a non-inheritance * situation. The duplicate RTE we added for the parent table is * harmless, so we don't bother to get rid of it. */ if (list_length(appinfos) < 2) { /* Clear flag before returning */ rte->inh = false; return; } /* Otherwise, OK to add to root->append_rel_list */ root->append_rel_list = list_concat(root->append_rel_list, appinfos); /* * The executor will check the parent table's access permissions when it * examines the parent's added RTE entry. There's no need to check twice, * so turn off access check bits in the original RTE. */ rte->requiredPerms = 0; } /* * make_inh_translation_lists * Build the lists of translations from parent Vars to child Vars for * an inheritance child. We need both a column number mapping list * and a list of Vars representing the child columns. * * For paranoia's sake, we match type as well as attribute name. */ static void make_inh_translation_lists(Relation oldrelation, Relation newrelation, Index newvarno, List **col_mappings, List **translated_vars) { List *numbers = NIL; List *vars = NIL; TupleDesc old_tupdesc = RelationGetDescr(oldrelation); TupleDesc new_tupdesc = RelationGetDescr(newrelation); int oldnatts = old_tupdesc->natts; int newnatts = new_tupdesc->natts; int old_attno; for (old_attno = 0; old_attno < oldnatts; old_attno++) { Form_pg_attribute att; char *attname; Oid atttypid; int32 atttypmod; int new_attno; att = old_tupdesc->attrs[old_attno]; if (att->attisdropped) { /* Just put 0/NULL into this list entry */ numbers = lappend_int(numbers, 0); vars = lappend(vars, NULL); continue; } attname = NameStr(att->attname); atttypid = att->atttypid; atttypmod = att->atttypmod; /* * When we are generating the "translation list" for the parent table * of an inheritance set, no need to search for matches. */ if (oldrelation == newrelation) { numbers = lappend_int(numbers, old_attno + 1); vars = lappend(vars, makeVar(newvarno, (AttrNumber) (old_attno + 1), atttypid, atttypmod, 0)); continue; } /* * Otherwise we have to search for the matching column by name. * There's no guarantee it'll have the same column position, because * of cases like ALTER TABLE ADD COLUMN and multiple inheritance. */ for (new_attno = 0; new_attno < newnatts; new_attno++) { att = new_tupdesc->attrs[new_attno]; if (att->attisdropped || att->attinhcount == 0) continue; if (strcmp(attname, NameStr(att->attname)) != 0) continue; /* Found it, check type */ if (atttypid != att->atttypid || atttypmod != att->atttypmod) elog(ERROR, "attribute \"%s\" of relation \"%s\" does not match parent's type", attname, RelationGetRelationName(newrelation)); numbers = lappend_int(numbers, new_attno + 1); vars = lappend(vars, makeVar(newvarno, (AttrNumber) (new_attno + 1), atttypid, atttypmod, 0)); break; } if (new_attno >= newnatts) elog(ERROR, "could not find inherited attribute \"%s\" of relation \"%s\"", attname, RelationGetRelationName(newrelation)); } *col_mappings = numbers; *translated_vars = vars; } /* * adjust_appendrel_attrs * Copy the specified query or expression and translate Vars referring * to the parent rel of the specified AppendRelInfo to refer to the * child rel instead. We also update rtindexes appearing outside Vars, * such as resultRelation and jointree relids. * * Note: this is only applied after conversion of sublinks to subplans, * so we don't need to cope with recursion into sub-queries. * * Note: this is not hugely different from what ResolveNew() does; maybe * we should try to fold the two routines together. */ Node * adjust_appendrel_attrs(Node *node, AppendRelInfo *appinfo) { Node *result; /* * Must be prepared to start with a Query or a bare expression tree. */ if (node && IsA(node, Query)) { Query *newnode; newnode = query_tree_mutator((Query *) node, adjust_appendrel_attrs_mutator, (void *) appinfo, QTW_IGNORE_RT_SUBQUERIES); if (newnode->resultRelation == appinfo->parent_relid) { newnode->resultRelation = appinfo->child_relid; /* Fix tlist resnos too, if it's inherited UPDATE */ if (newnode->commandType == CMD_UPDATE) newnode->targetList = adjust_inherited_tlist(newnode->targetList, appinfo); } result = (Node *) newnode; } else result = adjust_appendrel_attrs_mutator(node, appinfo); return result; } static Node * adjust_appendrel_attrs_mutator(Node *node, AppendRelInfo *context) { if (node == NULL) return NULL; if (IsA(node, Var)) { Var *var = (Var *) copyObject(node); if (var->varlevelsup == 0 && var->varno == context->parent_relid) { var->varno = context->child_relid; var->varnoold = context->child_relid; if (var->varattno > 0) { Node *newnode; if (var->varattno > list_length(context->translated_vars)) elog(ERROR, "attribute %d of relation \"%s\" does not exist", var->varattno, get_rel_name(context->parent_reloid)); newnode = copyObject(list_nth(context->translated_vars, var->varattno - 1)); if (newnode == NULL) elog(ERROR, "attribute %d of relation \"%s\" does not exist", var->varattno, get_rel_name(context->parent_reloid)); return newnode; } else if (var->varattno == 0) { /* * Whole-row Var: if we are dealing with named rowtypes, we * can use a whole-row Var for the child table plus a coercion * step to convert the tuple layout to the parent's rowtype. * Otherwise we have to generate a RowExpr. */ if (OidIsValid(context->child_reltype)) { Assert(var->vartype == context->parent_reltype); if (context->parent_reltype != context->child_reltype) { ConvertRowtypeExpr *r = makeNode(ConvertRowtypeExpr); r->arg = (Expr *) var; r->resulttype = context->parent_reltype; r->convertformat = COERCE_IMPLICIT_CAST; /* Make sure the Var node has the right type ID, too */ var->vartype = context->child_reltype; return (Node *) r; } } else { /* * Build a RowExpr containing the translated variables. */ RowExpr *rowexpr; List *fields; fields = (List *) copyObject(context->translated_vars); rowexpr = makeNode(RowExpr); rowexpr->args = fields; rowexpr->row_typeid = var->vartype; rowexpr->row_format = COERCE_IMPLICIT_CAST; return (Node *) rowexpr; } } /* system attributes don't need any other translation */ } return (Node *) var; } if (IsA(node, RangeTblRef)) { RangeTblRef *rtr = (RangeTblRef *) copyObject(node); if (rtr->rtindex == context->parent_relid) rtr->rtindex = context->child_relid; return (Node *) rtr; } if (IsA(node, JoinExpr)) { /* Copy the JoinExpr node with correct mutation of subnodes */ JoinExpr *j; j = (JoinExpr *) expression_tree_mutator(node, adjust_appendrel_attrs_mutator, (void *) context); /* now fix JoinExpr's rtindex (probably never happens) */ if (j->rtindex == context->parent_relid) j->rtindex = context->child_relid; return (Node *) j; } if (IsA(node, InClauseInfo)) { /* Copy the InClauseInfo node with correct mutation of subnodes */ InClauseInfo *ininfo; ininfo = (InClauseInfo *) expression_tree_mutator(node, adjust_appendrel_attrs_mutator, (void *) context); /* now fix InClauseInfo's relid sets */ ininfo->lefthand = adjust_relid_set(ininfo->lefthand, context->parent_relid, context->child_relid); ininfo->righthand = adjust_relid_set(ininfo->righthand, context->parent_relid, context->child_relid); return (Node *) ininfo; } /* Shouldn't need to handle OuterJoinInfo or AppendRelInfo here */ Assert(!IsA(node, OuterJoinInfo)); Assert(!IsA(node, AppendRelInfo)); /* * We have to process RestrictInfo nodes specially. */ if (IsA(node, RestrictInfo)) { RestrictInfo *oldinfo = (RestrictInfo *) node; RestrictInfo *newinfo = makeNode(RestrictInfo); /* Copy all flat-copiable fields */ memcpy(newinfo, oldinfo, sizeof(RestrictInfo)); /* Recursively fix the clause itself */ newinfo->clause = (Expr *) adjust_appendrel_attrs_mutator((Node *) oldinfo->clause, context); /* and the modified version, if an OR clause */ newinfo->orclause = (Expr *) adjust_appendrel_attrs_mutator((Node *) oldinfo->orclause, context); /* adjust relid sets too */ newinfo->clause_relids = adjust_relid_set(oldinfo->clause_relids, context->parent_relid, context->child_relid); newinfo->required_relids = adjust_relid_set(oldinfo->required_relids, context->parent_relid, context->child_relid); newinfo->left_relids = adjust_relid_set(oldinfo->left_relids, context->parent_relid, context->child_relid); newinfo->right_relids = adjust_relid_set(oldinfo->right_relids, context->parent_relid, context->child_relid); /* * Reset cached derivative fields, since these might need to have * different values when considering the child relation. */ newinfo->eval_cost.startup = -1; newinfo->this_selec = -1; newinfo->left_ec = NULL; newinfo->right_ec = NULL; newinfo->left_em = NULL; newinfo->right_em = NULL; newinfo->scansel_cache = NIL; newinfo->left_bucketsize = -1; newinfo->right_bucketsize = -1; return (Node *) newinfo; } /* * NOTE: we do not need to recurse into sublinks, because they should * already have been converted to subplans before we see them. */ Assert(!IsA(node, SubLink)); Assert(!IsA(node, Query)); /* * BUT: although we don't need to recurse into subplans, we do need to * make sure that they are copied, not just referenced as * expression_tree_mutator will do by default. Otherwise we'll have the * same subplan node referenced from each arm of the finished APPEND plan, * which will cause trouble in the executor. This is a kluge that should * go away when we redesign querytrees. */ if (is_subplan(node)) { SubPlan *subplan; /* Copy the node and process subplan args */ node = expression_tree_mutator(node, adjust_appendrel_attrs_mutator, (void *) context); /* Make sure we have separate copies of subplan and its rtable */ subplan = (SubPlan *) node; subplan->plan = copyObject(subplan->plan); subplan->rtable = copyObject(subplan->rtable); return node; } return expression_tree_mutator(node, adjust_appendrel_attrs_mutator, (void *) context); } /* * Substitute newrelid for oldrelid in a Relid set */ static Relids adjust_relid_set(Relids relids, Index oldrelid, Index newrelid) { if (bms_is_member(oldrelid, relids)) { /* Ensure we have a modifiable copy */ relids = bms_copy(relids); /* Remove old, add new */ relids = bms_del_member(relids, oldrelid); relids = bms_add_member(relids, newrelid); } return relids; } /* * adjust_appendrel_attr_needed * Adjust an attr_needed[] array to reference a member rel instead of * the original appendrel * * oldrel: source of data (we use the attr_needed, min_attr, max_attr fields) * appinfo: supplies parent_relid, child_relid, col_mappings * new_min_attr, new_max_attr: desired bounds of new attr_needed array * * The relid sets are adjusted by substituting child_relid for parent_relid. * (NOTE: oldrel is not necessarily the parent_relid relation!) We are also * careful to map attribute numbers within the array properly. User * attributes have to be mapped through col_mappings, but system attributes * and whole-row references always have the same attno. * * Returns a palloc'd array with the specified bounds */ Relids * adjust_appendrel_attr_needed(RelOptInfo *oldrel, AppendRelInfo *appinfo, AttrNumber new_min_attr, AttrNumber new_max_attr) { Relids *new_attr_needed; Index parent_relid = appinfo->parent_relid; Index child_relid = appinfo->child_relid; int parent_attr; ListCell *lm; /* Create empty result array */ Assert(new_min_attr <= oldrel->min_attr); Assert(new_max_attr >= oldrel->max_attr); new_attr_needed = (Relids *) palloc0((new_max_attr - new_min_attr + 1) * sizeof(Relids)); /* Process user attributes, with appropriate attno mapping */ parent_attr = 1; foreach(lm, appinfo->col_mappings) { int child_attr = lfirst_int(lm); if (child_attr > 0) { Relids attrneeded; Assert(parent_attr <= oldrel->max_attr); Assert(child_attr <= new_max_attr); attrneeded = oldrel->attr_needed[parent_attr - oldrel->min_attr]; attrneeded = adjust_relid_set(attrneeded, parent_relid, child_relid); new_attr_needed[child_attr - new_min_attr] = attrneeded; } parent_attr++; } /* Process system attributes, including whole-row references */ for (parent_attr = oldrel->min_attr; parent_attr <= 0; parent_attr++) { Relids attrneeded; attrneeded = oldrel->attr_needed[parent_attr - oldrel->min_attr]; attrneeded = adjust_relid_set(attrneeded, parent_relid, child_relid); new_attr_needed[parent_attr - new_min_attr] = attrneeded; } return new_attr_needed; } /* * Adjust the targetlist entries of an inherited UPDATE operation * * The expressions have already been fixed, but we have to make sure that * the target resnos match the child table (they may not, in the case of * a column that was added after-the-fact by ALTER TABLE). In some cases * this can force us to re-order the tlist to preserve resno ordering. * (We do all this work in special cases so that preptlist.c is fast for * the typical case.) * * The given tlist has already been through expression_tree_mutator; * therefore the TargetEntry nodes are fresh copies that it's okay to * scribble on. * * Note that this is not needed for INSERT because INSERT isn't inheritable. */ static List * adjust_inherited_tlist(List *tlist, AppendRelInfo *context) { bool changed_it = false; ListCell *tl; List *new_tlist; bool more; int attrno; /* This should only happen for an inheritance case, not UNION ALL */ Assert(OidIsValid(context->parent_reloid)); /* Scan tlist and update resnos to match attnums of child rel */ foreach(tl, tlist) { TargetEntry *tle = (TargetEntry *) lfirst(tl); int newattno; if (tle->resjunk) continue; /* ignore junk items */ /* Look up the translation of this column */ if (tle->resno <= 0 || tle->resno > list_length(context->col_mappings)) elog(ERROR, "attribute %d of relation \"%s\" does not exist", tle->resno, get_rel_name(context->parent_reloid)); newattno = list_nth_int(context->col_mappings, tle->resno - 1); if (newattno <= 0) elog(ERROR, "attribute %d of relation \"%s\" does not exist", tle->resno, get_rel_name(context->parent_reloid)); if (tle->resno != newattno) { tle->resno = newattno; changed_it = true; } } /* * If we changed anything, re-sort the tlist by resno, and make sure * resjunk entries have resnos above the last real resno. The sort * algorithm is a bit stupid, but for such a seldom-taken path, small is * probably better than fast. */ if (!changed_it) return tlist; new_tlist = NIL; more = true; for (attrno = 1; more; attrno++) { more = false; foreach(tl, tlist) { TargetEntry *tle = (TargetEntry *) lfirst(tl); if (tle->resjunk) continue; /* ignore junk items */ if (tle->resno == attrno) new_tlist = lappend(new_tlist, tle); else if (tle->resno > attrno) more = true; } } foreach(tl, tlist) { TargetEntry *tle = (TargetEntry *) lfirst(tl); if (!tle->resjunk) continue; /* here, ignore non-junk items */ tle->resno = attrno; new_tlist = lappend(new_tlist, tle); attrno++; } return new_tlist; }