JSON 格式的查询计划

EXPLAIN JSON 以 JSON 格式返回查询计划。例如：

=> EXPLAIN JSON SELECT customer_name, customer_state FROM customer_dimension
     WHERE customer_state IN ('MA','NH') AND customer_gender='Male' ORDER BY customer_name LIMIT 10;
 ------------------------------
{
     "PARAMETERS" : {
         "QUERY_STRING" : "EXPLAIN JSON SELECT customer_name, customer_state FROM customer_dimension \n
         WHERE customer_state IN ('MA','NH') AND customer_gender='Male' ORDER BY customer_name LIMIT 10;"
     },
     "PLAN" : {
         "PATH_ID" : 0,
         "PATH_NAME" : "SELECT",
         "EXTRA" : " LIMIT 10",
         "COST" : 2114.000000,
         "ROWS" : 10.000000,
         "COST_STATUS" : "NO_STATISTICS",
         "TUPLE_LIMIT" : 10,
         "EXECUTE_NODE" : "Query Initiator",
         "INPUT" : {
             "PATH_ID" : 1,
             "PATH_NAME" : "SORT",
             "EXTRA" : "[TOPK]",
             "COST" : 2114.000000,
             "ROWS" : 49998.000000,
             "COST_STATUS" : "NO_STATISTICS",
             "ORDER" : ["customer_dimension.customer_name", "customer_dimension.customer_state"],
             "TUPLE_LIMIT" : 10,
             "EXECUTE_NODE" : "All Nodes",
             "INPUT" : {
                 "PATH_ID" : 2,
                 "PATH_NAME" : "STORAGE ACCESS",
                 "EXTRA" : "for customer_dimension",
                 "COST" : 252.000000,
                 "ROWS" : 49998.000000,
                 "COST_STATUS" : "NO_STATISTICS",
                 "TABLE" : "public.customer_dimension",
                 "PROJECTION" : "public.customer_dimension_b0",
                 "MATERIALIZE" : ["customer_dimension.customer_name", "customer_dimension.customer_state"],
                 "FILTER" : ["(customer_dimension.customer_state = ANY (ARRAY['MA', 'NH']))", "(customer_dimension.customer_gender = 'Male')"],
                 "EXECUTE_NODE" : "All Nodes"
          "SIP" : "Runtime Filter: (SIP1(TopK): customer_dimension.customer_name)"

             }
         }
     }
 }
(40 rows)