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@ -7,7 +7,7 @@ |
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* |
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* |
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* IDENTIFICATION |
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* $Header: /cvsroot/pgsql/src/backend/parser/parse_agg.c,v 1.4 1997/12/22 05:42:19 momjian Exp $ |
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* $Header: /cvsroot/pgsql/src/backend/parser/parse_agg.c,v 1.5 1998/01/04 04:31:14 momjian Exp $ |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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@ -18,14 +18,17 @@ |
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#include "postgres.h" |
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#include "access/heapam.h" |
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#include "catalog/pg_aggregate.h" |
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#include "catalog/pg_type.h" |
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#include "nodes/nodeFuncs.h" |
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#include "nodes/primnodes.h" |
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#include "nodes/relation.h" |
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#include "optimizer/clauses.h" |
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#include "parser/parse_agg.h" |
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#include "parser/parse_expr.h" |
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#include "parser/parse_node.h" |
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#include "parser/parse_target.h" |
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#include "utils/syscache.h" |
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#include "utils/lsyscache.h" |
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static bool contain_agg_clause(Node *clause); |
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static bool exprIsAggOrGroupCol(Node *expr, List *groupClause); |
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@ -276,7 +279,8 @@ parseCheckAggregates(ParseState *pstate, Query *qry) |
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Aggreg * |
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ParseAgg(char *aggname, Oid basetype, Node *target) |
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ParseAgg(ParseState *pstate, char *aggname, Oid basetype, |
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List *target, int precedence) |
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{ |
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Oid fintype; |
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Oid vartype; |
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@ -284,6 +288,7 @@ ParseAgg(char *aggname, Oid basetype, Node *target) |
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Form_pg_aggregate aggform; |
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Aggreg *aggreg; |
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HeapTuple theAggTuple; |
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bool usenulls = false; |
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theAggTuple = SearchSysCacheTuple(AGGNAME, PointerGetDatum(aggname), |
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ObjectIdGetDatum(basetype), |
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@ -293,21 +298,78 @@ ParseAgg(char *aggname, Oid basetype, Node *target) |
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elog(WARN, "aggregate %s does not exist", aggname); |
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} |
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/*
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* We do a major hack for count(*) here. |
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* |
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* Count(*) poses several problems. First, we need a field that is |
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* guaranteed to be in the range table, and unique. Using a constant |
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* causes the optimizer to properly remove the aggragate from any |
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* elements of the query. |
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* Using just 'oid', which can not be null, in the parser fails on: |
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* |
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* select count(*) from tab1, tab2 -- oid is not unique |
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* select count(*) from viewtable -- views don't have real oids |
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* |
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* So, for an aggregate with parameter '*', we use the first valid |
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* range table entry, and pick the first column from the table. |
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* We set a flag to count nulls, because we could have nulls in |
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* that column. |
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*/ |
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if (nodeTag(lfirst(target)) == T_Const) |
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{ |
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Const *con = (Const *)lfirst(target); |
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if (con->consttype == UNKNOWNOID && VARSIZE(con->constvalue) == VARHDRSZ) |
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{ |
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Attr *attr = makeNode(Attr); |
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List *rtable, *rlist; |
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RangeTblEntry *first_valid_rte; |
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Assert(lnext(target) == NULL); |
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if (pstate->p_is_rule) |
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rtable = lnext(lnext(pstate->p_rtable)); |
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else |
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rtable = pstate->p_rtable; |
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first_valid_rte = NULL; |
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foreach(rlist, rtable) |
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{ |
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RangeTblEntry *rte = lfirst(rlist); |
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/* only entries on outer(non-function?) scope */ |
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if (!rte->inFromCl && rte != pstate->p_target_rangetblentry) |
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continue; |
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first_valid_rte =rte; |
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break; |
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} |
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if (first_valid_rte == NULL) |
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elog(WARN, "Can't find column to do aggregate(*) on."); |
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attr->relname = first_valid_rte->refname; |
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attr->attrs = lcons(makeString( |
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get_attname(first_valid_rte->relid,1)),NIL); |
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lfirst(target) = transformExpr(pstate, (Node *) attr, precedence); |
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usenulls = true; |
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} |
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} |
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aggform = (Form_pg_aggregate) GETSTRUCT(theAggTuple); |
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fintype = aggform->aggfinaltype; |
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xfn1 = aggform->aggtransfn1; |
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if (nodeTag(target) != T_Var && nodeTag(target) != T_Expr) |
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elog(WARN, "parser: aggregate can only be applied on an attribute or expression"); |
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/* only aggregates with transfn1 need a base type */ |
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if (OidIsValid(xfn1)) |
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{ |
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basetype = aggform->aggbasetype; |
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if (nodeTag(target) == T_Var) |
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vartype = ((Var *) target)->vartype; |
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if (nodeTag(lfirst(target)) == T_Var) |
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vartype = ((Var *) lfirst(target))->vartype; |
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else |
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vartype = ((Expr *) target)->typeOid; |
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vartype = ((Expr *) lfirst(target))->typeOid; |
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if (basetype != vartype) |
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{ |
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@ -327,7 +389,9 @@ ParseAgg(char *aggname, Oid basetype, Node *target) |
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aggreg->basetype = aggform->aggbasetype; |
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aggreg->aggtype = fintype; |
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aggreg->target = target; |
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aggreg->target = lfirst(target); |
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if (usenulls) |
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aggreg->usenulls = true; |
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return aggreg; |
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} |
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Bruce Momjian
28 years ago