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Remove ruleutils.c's use of varnoold/varoattno as a shortcut for determining 

what a Var node refers to.  This is no longer necessary because the new
flat-range-table representation of plan trees makes it relatively easy to dig
down through child plan levels to find the original reference; and to keep
doing it that way, we'd have to store joinaliasvars lists in flattened RTEs,
as demonstrated by bug report from Leszek Trenkner.  This change makes
varnoold/varoattno truly just debug aids, which wasn't quite the case before.
Perhaps we should drop them, or only have them in assert-enabled builds?
This commit is contained in:
Tom Lane 2007-05-24 18:58:42 +00:00
parent a868e24660
commit ce5b24abed
1 changed files with 20 additions and 16 deletions
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36
src/backend/utils/adt/ruleutils.c
View File

@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.257 2007/03/27 23:21:10 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.258 2007/05/24 18:58:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -2598,20 +2598,14 @@ get_variable(Var *var, int levelsup, bool showstar, deparse_context *context)
/*
* Try to find the relevant RTE in this rtable. In a plan tree, it's
* likely that varno is OUTER or INNER, in which case we try to use
* varnoold instead. If the Var references an expression computed by a
* subplan, varnoold will be 0, and we must dig down into the subplans.
* likely that varno is OUTER or INNER, in which case we must dig down
* into the subplans.
*/
if (var->varno >= 1 && var->varno <= list_length(dpns->rtable))
{
rte = rt_fetch(var->varno, dpns->rtable);
attnum = var->varattno;
}
else if (var->varnoold >= 1 && var->varnoold <= list_length(dpns->rtable))
{
rte = rt_fetch(var->varnoold, dpns->rtable);
attnum = var->varoattno;
}
else if (var->varno == OUTER && dpns->outer_plan)
{
TargetEntry *tle;
@ -2631,9 +2625,11 @@ get_variable(Var *var, int levelsup, bool showstar, deparse_context *context)
* Force parentheses because our caller probably assumed a Var is a
* simple expression.
*/
appendStringInfoChar(buf, '(');
if (!IsA(tle->expr, Var))
appendStringInfoChar(buf, '(');
get_rule_expr((Node *) tle->expr, context, true);
appendStringInfoChar(buf, ')');
if (!IsA(tle->expr, Var))
appendStringInfoChar(buf, ')');
dpns->outer_plan = save_outer;
dpns->inner_plan = save_inner;
@ -2658,9 +2654,11 @@ get_variable(Var *var, int levelsup, bool showstar, deparse_context *context)
* Force parentheses because our caller probably assumed a Var is a
* simple expression.
*/
appendStringInfoChar(buf, '(');
if (!IsA(tle->expr, Var))
appendStringInfoChar(buf, '(');
get_rule_expr((Node *) tle->expr, context, true);
appendStringInfoChar(buf, ')');
if (!IsA(tle->expr, Var))
appendStringInfoChar(buf, ')');
dpns->outer_plan = save_outer;
dpns->inner_plan = save_inner;
@ -2700,7 +2698,13 @@ get_variable(Var *var, int levelsup, bool showstar, deparse_context *context)
* simple reference, we have to just print the unqualified
* variable name (this can only happen with columns that were
* merged by USING or NATURAL clauses).
*
* This wouldn't work in decompiling plan trees, because we don't
* store joinaliasvars lists after planning; but a plan tree
* should never contain a join alias variable.
*/
if (rte->joinaliasvars == NIL)
elog(ERROR, "cannot decompile join alias var in plan tree");
if (attnum > 0)
{
Var *aliasvar;
@ -2798,9 +2802,7 @@ get_name_for_var_field(Var *var, int fieldno,
/*
* Try to find the relevant RTE in this rtable. In a plan tree, it's
* likely that varno is OUTER or INNER, in which case we must dig down
* into the subplans. (We can't shortcut with varnoold here, because
* it might reference a SUBQUERY RTE; we have to dig down to the
* SubqueryScan plan level to cope with that. See below.)
* into the subplans.
*/
if (var->varno >= 1 && var->varno <= list_length(dpns->rtable))
{
@ -2963,6 +2965,8 @@ get_name_for_var_field(Var *var, int fieldno,
break;
case RTE_JOIN:
/* Join RTE --- recursively inspect the alias variable */
if (rte->joinaliasvars == NIL)
elog(ERROR, "cannot decompile join alias var in plan tree");
Assert(attnum > 0 && attnum <= list_length(rte->joinaliasvars));
expr = (Node *) list_nth(rte->joinaliasvars, attnum - 1);
if (IsA(expr, Var))