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Restructure representation of join alias variables. An explicit JOIN

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now has an RTE of its own, and references to its outputs now are Vars
referencing the JOIN RTE, rather than CASE-expressions.  This allows
reverse-listing in ruleutils.c to use the correct alias easily, rather
than painfully reverse-engineering the alias namespace as it used to do.
Also, nested FULL JOINs work correctly, because the result of the inner
joins are simple Vars that the planner can cope with.  This fixes a bug
reported a couple times now, notably by Tatsuo on 18-Nov-01.  The alias
Vars are expanded into COALESCE expressions where needed at the very end
of planning, rather than during parsing.
Also, beginnings of support for showing plan qualifier expressions in
EXPLAIN.  There are probably still cases that need work.
initdb forced due to change of stored-rule representation.
This commit is contained in:
Tom Lane
2002-03-12 00:52:10 +00:00
parent 66b6bf67a1
commit 6eeb95f0f5
41 changed files with 1950 additions and 996 deletions
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44
src/backend/parser/analyze.c
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@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.219 2002/03/10 06:02:23 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.220 2002/03/12 00:51:52 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -2045,10 +2045,12 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
Node *node;
List *lefttl,
*dtlist,
*targetvars,
*colMods,
*targetnames,
*sv_namespace;
JoinExpr *jnode;
*sv_namespace,
*sv_rtable;
RangeTblEntry *jrte;
RangeTblRef *jrtr;
int tllen;
qry->commandType = CMD_SELECT;
@ -2115,12 +2117,14 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
/*
* Generate dummy targetlist for outer query using column names of
* leftmost select and common datatypes of topmost set operation. Also
* make lists of the dummy vars and their names for use in parsing
* ORDER BY.
* make a list of the column names for use in parsing ORDER BY.
*
* XXX colMods is a hack to provide a dummy typmod list below. We
* should probably keep track of common typmod instead.
*/
qry->targetList = NIL;
targetvars = NIL;
targetnames = NIL;
colMods = NIL;
lefttl = leftmostQuery->targetList;
foreach(dtlist, sostmt->colTypes)
{
@ -2135,15 +2139,15 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
-1,
colName,
false);
expr = (Node *) makeVar(leftmostRTI,
expr = (Node *) makeVar(1,
leftResdom->resno,
colType,
-1,
0);
qry->targetList = lappend(qry->targetList,
makeTargetEntry(resdom, expr));
targetvars = lappend(targetvars, expr);
targetnames = lappend(targetnames, makeString(colName));
colMods = lappendi(colMods, -1);
lefttl = lnext(lefttl);
}
@ -2190,7 +2194,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
/*
* As a first step towards supporting sort clauses that are
* expressions using the output columns, generate a namespace entry
* that makes the output columns visible. A JoinExpr node is handy
* that makes the output columns visible. A Join RTE node is handy
* for this, since we can easily control the Vars generated upon
* matches.
*
@ -2198,12 +2202,23 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
* "ORDER BY upper(foo)" will draw the right error message rather than
* "foo not found".
*/
jnode = makeNode(JoinExpr);
jnode->colnames = targetnames;
jnode->colvars = targetvars;
jrte = addRangeTableEntryForJoin(NULL,
targetnames,
JOIN_INNER,
sostmt->colTypes,
colMods,
NIL,
NIL,
NULL,
true);
jrtr = makeNode(RangeTblRef);
jrtr->rtindex = 1;
sv_rtable = pstate->p_rtable;
pstate->p_rtable = makeList1(jrte);
sv_namespace = pstate->p_namespace;
pstate->p_namespace = makeList1(jnode);
pstate->p_namespace = makeList1(jrtr);
/*
* For now, we don't support resjunk sort clauses on the output of a
@ -2218,6 +2233,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
qry->targetList);
pstate->p_namespace = sv_namespace;
pstate->p_rtable = sv_rtable;
if (tllen != length(qry->targetList))
elog(ERROR, "ORDER BY on a UNION/INTERSECT/EXCEPT result must be on one of the result columns");