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Another round of planner fixes for LATERAL.

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Formerly, subquery pullup had no need to examine other entries in the range
table, since they could not contain any references to the subquery being
pulled up.  That's no longer true with LATERAL, so now we need to be able
to visit rangetable subexpressions to replace Vars referencing the
pulled-up subquery.  Also, this means that extract_lateral_references must
be unsurprised at encountering lateral PlaceHolderVars, since such might be
created when pulling up a subquery that's underneath an outer join with
respect to the lateral reference.
This commit is contained in:
Tom Lane
2012-08-18 14:10:17 -04:00
parent 18226849ea
commit 084a29c94f
5 changed files with 205 additions and 10 deletions
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17
src/backend/optimizer/util/var.c
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@ -247,11 +247,8 @@ pull_varattnos_walker(Node *node, pull_varattnos_context *context)
/*
* pull_vars_of_level
* Create a list of all Vars referencing the specified query level
* in the given parsetree.
*
* This is used on unplanned parsetrees, so we don't expect to see any
* PlaceHolderVars.
* Create a list of all Vars (and PlaceHolderVars) referencing the
* specified query level in the given parsetree.
*
* Caution: the Vars are not copied, only linked into the list.
*/
@ -288,7 +285,15 @@ pull_vars_walker(Node *node, pull_vars_context *context)
context->vars = lappend(context->vars, var);
return false;
}
Assert(!IsA(node, PlaceHolderVar));
if (IsA(node, PlaceHolderVar))
{
PlaceHolderVar *phv = (PlaceHolderVar *) node;
if (phv->phlevelsup == context->sublevels_up)
context->vars = lappend(context->vars, phv);
/* we don't want to look into the contained expression */
return false;
}
if (IsA(node, Query))
{
/* Recurse into RTE subquery or not-yet-planned sublink subquery */