diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/utils/adt/selfuncs.c | 11 | ||||
| -rw-r--r-- | src/include/nodes/relation.h | 4 |
2 files changed, 13 insertions, 2 deletions
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c index a7a06146a06..23e5526a8e1 100644 --- a/src/backend/utils/adt/selfuncs.c +++ b/src/backend/utils/adt/selfuncs.c @@ -5009,6 +5009,17 @@ get_variable_numdistinct(VariableStatData *vardata, bool *isdefault) */ stadistinct = 2.0; } + else if (vardata->rel && vardata->rel->rtekind == RTE_VALUES) + { + /* + * If the Var represents a column of a VALUES RTE, assume it's unique. + * This could of course be very wrong, but it should tend to be true + * in well-written queries. We could consider examining the VALUES' + * contents to get some real statistics; but that only works if the + * entries are all constants, and it would be pretty expensive anyway. + */ + stadistinct = -1.0; /* unique (and all non null) */ + } else { /* diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h index be2028867a8..3ccc9d1b037 100644 --- a/src/include/nodes/relation.h +++ b/src/include/nodes/relation.h @@ -407,7 +407,7 @@ typedef struct PlannerInfo * * relid - RTE index (this is redundant with the relids field, but * is provided for convenience of access) - * rtekind - distinguishes plain relation, subquery, or function RTE + * rtekind - copy of RTE's rtekind field * min_attr, max_attr - range of valid AttrNumbers for rel * attr_needed - array of bitmapsets indicating the highest joinrel * in which each attribute is needed; if bit 0 is set then @@ -552,7 +552,7 @@ typedef struct RelOptInfo /* information about a base rel (not set for join rels!) */ Index relid; Oid reltablespace; /* containing tablespace */ - RTEKind rtekind; /* RELATION, SUBQUERY, or FUNCTION */ + RTEKind rtekind; /* RELATION, SUBQUERY, FUNCTION, etc */ AttrNumber min_attr; /* smallest attrno of rel (often <0) */ AttrNumber max_attr; /* largest attrno of rel */ Relids *attr_needed; /* array indexed [min_attr .. max_attr] */ |