diff options
Diffstat (limited to 'src/backend/optimizer/plan/initsplan.c')
| -rw-r--r-- | src/backend/optimizer/plan/initsplan.c | 46 |
1 files changed, 26 insertions, 20 deletions
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c index 20a01902efc..ef219245aab 100644 --- a/src/backend/optimizer/plan/initsplan.c +++ b/src/backend/optimizer/plan/initsplan.c @@ -7,7 +7,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/initsplan.c,v 1.39 1999/08/26 05:07:41 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/initsplan.c,v 1.40 1999/10/07 04:23:06 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -77,15 +77,21 @@ add_vars_to_targetlist(Query *root, List *vars) } /* - * add_missing_vars_to_tlist - * If we have range variable(s) in the FROM clause that does not appear - * in the target list nor qualifications, we add it to the base relation - * list. For instance, "select f.x from foo f, foo f2" is a join of f and - * f2. Note that if we have "select foo.x from foo f", it also gets turned - * into a join. + * add_missing_rels_to_query + * + * If we have a range variable in the FROM clause that does not appear + * in the target list nor qualifications, we must add it to the base + * relation list so that it will be joined. For instance, "select f.x + * from foo f, foo f2" is a join of f and f2. Note that if we have + * "select foo.x from foo f", it also gets turned into a join (between + * foo as foo and foo as f). + * + * To avoid putting useless entries into the per-relation targetlists, + * this should only be called after all the variables in the targetlist + * and quals have been processed by the routines above. */ void -add_missing_vars_to_tlist(Query *root, List *tlist) +add_missing_rels_to_query(Query *root) { int varno = 1; List *l; @@ -93,21 +99,21 @@ add_missing_vars_to_tlist(Query *root, List *tlist) foreach(l, root->rtable) { RangeTblEntry *rte = (RangeTblEntry *) lfirst(l); - Relids relids; - relids = lconsi(varno, NIL); - if (rte->inFromCl && !rel_member(relids, root->base_rel_list)) + if (rte->inJoinSet) { - RelOptInfo *rel; - Var *var; - - /* add it to base_rel_list */ - rel = get_base_rel(root, varno); - /* give it a dummy tlist entry for its OID */ - var = makeVar(varno, ObjectIdAttributeNumber, OIDOID, -1, 0); - add_var_to_tlist(rel, var); + RelOptInfo *rel = get_base_rel(root, varno); + + /* If the rel isn't otherwise referenced, give it a dummy + * targetlist consisting of its own OID. + */ + if (rel->targetlist == NIL) + { + Var *var = makeVar(varno, ObjectIdAttributeNumber, + OIDOID, -1, 0); + add_var_to_tlist(rel, var); + } } - pfree(relids); varno++; } } |