Function execute_single

src/cypher/cypher.c:4821–4888

}

static int execute_single(cbm_store_t *store, cbm_query_t *q, const char *project, int max_rows,
                          result_builder_t *rb) {
    cbm_pattern_t *pat0 = &q->patterns[0];

    /* Step 1: Scan initial nodes */
    cbm_node_t *scanned = NULL;
    int scan_count = 0;
    scan_pattern_nodes(store, project, &pat0->nodes[0], &scanned, &scan_count);

    /* Build initial bindings with early WHERE */
    int bind_cap = scan_count > max_rows ? scan_count : (max_rows > 0 ? max_rows : SKIP_ONE);
    binding_t *bindings = malloc((bind_cap + SKIP_ONE) * sizeof(binding_t));
    int bind_count = 0;
    const char *var_name = pat0->nodes[0].variable ? pat0->nodes[0].variable : "_n0";

    for (int i = 0; i < scan_count && bind_count < bind_cap; i++) {
        if ((i & CYPHER_DEADLINE_CHECK_MASK) == 0 && cypher_deadline_exceeded()) {
            break;
        }
        binding_t b = {0};
        b.store = store;
        binding_set(&b, var_name, &scanned[i]);
        bool pass = !q->where || eval_where(q->where, &b);
        if (pass) {
            bindings[bind_count++] = b;
        } else {
            binding_free(&b);
        }
    }

    /* Step 2: Expand first pattern's relationships */
    expand_pattern_rels(store, pat0, &bindings, &bind_count, &bind_cap, &var_name,
                        q->pattern_optional[0]);

    /* Step 2b: Additional patterns */
    if (expand_additional_patterns(store, q, project, max_rows, &bindings, &bind_count,
                                   &bind_cap) != 0) {
        for (int bi = 0; bi < bind_count; bi++) {
            binding_free(&bindings[bi]);
        }
        free(bindings);
        cbm_store_free_nodes(scanned, scan_count);
        return CBM_NOT_FOUND; /* cross-join allocation refused/failed */
    }

    /* Step 3: Late WHERE */
    if (q->where && (pat0->rel_count > 0 || q->pattern_count > SKIP_ONE)) {
        filter_bindings_where(q->where, bindings, &bind_count);
    }

    /* Step 3b: WITH clause */
    execute_with_clause(q, &bindings, &bind_count);

    /* Step 4: Project results */
    rb_init(rb);
    if (q->ret) {
        execute_return_clause(q, q->ret, bindings, bind_count, max_rows, rb);
    } else {