/* * build_simple_rel *      Construct a new RelOptInfo for a base relation or 'other' relation. */RelOptInfo *build_simple_rel(PlannerInfo *root, int relid, RelOptKind reloptkind){    RelOptInfo *rel;    RangeTblEntry *rte;    /* Rel should not exist already */    Assert(relid > 0 && relid < root->simple_rel_array_size);    if (root->simple_rel_array[relid] != NULL)        elog(ERROR, "rel %d already exists", relid);    /* Fetch RTE for relation */    rte = root->simple_rte_array[relid];    Assert(rte != NULL);    rel = makeNode(RelOptInfo);    rel->reloptkind = reloptkind;    rel->relids = bms_make_singleton(relid);    rel->rows = 0;    ...    rel->has_eclass_joins = false;    /* Check type of rtable entry */    switch (rte->rtekind)    {        case RTE_RELATION:            /* Table --- retrieve statistics from the system catalogs */            get_relation_info(root, rte->relid, rte->inh, rel);            break;        case RTE_SUBQUERY:        case RTE_FUNCTION:        case RTE_VALUES:        case RTE_CTE:            /*             * Subquery, function, or values list --- set up attr range and             * arrays             *             * Note: 0 is included in range to support whole-row Vars             */            rel->min_attr = 0;            rel->max_attr = list_length(rte->eref->colnames);            rel->attr_needed = (Relids *)                palloc0((rel->max_attr - rel->min_attr + 1) * sizeof(Relids));            rel->attr_widths = (int32 *)                palloc0((rel->max_attr - rel->min_attr + 1) * sizeof(int32));            break;        default:            elog(ERROR, "unrecognized RTE kind: %d",                 (int) rte->rtekind);            break;    }    /* Save the finished struct in the query's simple_rel_array */    root->simple_rel_array[relid] = rel;    ...    return rel;}

root->simple_rel_array[relid] = rel;