diff options
Diffstat (limited to 'src/backend/optimizer/plan/subselect.c')
| -rw-r--r-- | src/backend/optimizer/plan/subselect.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c index d7d25c09f80..11612f408c9 100644 --- a/src/backend/optimizer/plan/subselect.c +++ b/src/backend/optimizer/plan/subselect.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.82 2003/08/08 21:41:51 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.83 2003/10/18 16:52:15 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -493,8 +493,8 @@ make_subplan(SubLink *slink, List *lefthand, bool isTopQual) * If rtindex is 0, we build Params to represent the sub-select outputs. * The paramids of the Params created are returned in the *righthandIds list. * - * If rtindex is not 0, we build Vars using that rtindex as varno. The - * Vars themselves are returned in *righthandIds (this is a bit of a type + * If rtindex is not 0, we build Vars using that rtindex as varno. Copies + * of the Var nodes are returned in *righthandIds (this is a bit of a type * cheat, but we can get away with it). */ static List * @@ -525,8 +525,11 @@ convert_sublink_opers(List *lefthand, List *operOids, te->resdom->restype, te->resdom->restypmod, 0); - /* Record it for caller */ - *righthandIds = lappend(*righthandIds, rightop); + /* + * Copy it for caller. NB: we need a copy to avoid having + * doubly-linked substructure in the modified parse tree. + */ + *righthandIds = lappend(*righthandIds, copyObject(rightop)); } else { @@ -735,7 +738,7 @@ convert_IN_to_join(Query *parse, SubLink *sublink) /* * Build the result qual expressions. As a side effect, - * ininfo->sub_targetlist is filled with a list of the Vars + * ininfo->sub_targetlist is filled with a list of Vars * representing the subselect outputs. */ exprs = convert_sublink_opers(sublink->lefthand, |