sql限流

OceanBase
#1

MySQL [test]> select * from item limit 10; ±-----±--------±-------------------------±--------±---------------------------------------------------+ | i_id | i_im_id | i_name | i_price | i_data | ±-----±--------±-------------------------±--------±---------------------------------------------------+ | 1 | 9162 | M2hK5diA0N8pxwSwbi1ws | 78.88 | OI8B2wtJUXhqc7VEluyqcqcmjV7utVCUx | | 2 | 1634 | jmKGtKYb9kHMokjV | 73.87 | dBvPTlaGtMFs7mGo8s8xQOFMORIGINALdftNL6VcqnZodx | | 3 | 5724 | sKWvf89TxGQJN8FwqWXBU9Df | 2.04 | c13xmR3RIo3zHEG10YruX9KPOX | | 4 | 9842 | cs4fyduo6ZeduE1LYRkdL85 | 43.01 | 0MqyhP7ccGlV9VftTMtxNtIEQYGQYD | | 5 | 4644 | oVxFBzWVrq5PuoSc | 79.41 | XryBnJ2jtXM1aTDMcMDew0w64Lz8eQBm7WyT8dhW2T0RsnEFQy | | 6 | 3992 | z9vsThtGHJtsFN | 50.00 | MVMTZbttusNBRKaQGv94e8zUmOEvYBShGVWB2k4BruabcdlWhs | | 7 | 2129 | s12IfH8x1ZrXqFs | 81.72 | e5GwoyT2DyD1kvocEpHBr3CQ5vclTURKQNb9wlYIZ | | 8 | 2613 | hEn8fTTZC6lHDOTz | 13.04 | MGsq6IyTdvMAyedttvIl6vCi4DXnJhsQG4a9U7U16p4Gt | | 9 | 8503 | NMrQ7CGScLigaHhL | 59.47 | lsLsBKB35lQ33ZjVzGycMy2cCw | | 10 | 7927 | LFrqCGaBLRhfXyJVxceo9 | 90.79 | NqoShdqo6ZTrbMtFWs9433vnHRSQGJ6jxmwTRB | ±-----±--------±-------------------------±--------±---------------------------------------------------+ 10 rows in set (0.02 sec) MySQL [test]> select * from item where i_id = 1; ±-----±--------±----------------------±--------±----------------------------------+ | i_id | i_im_id | i_name | i_price | i_data | ±-----±--------±----------------------±--------±----------------------------------+ | 1 | 9162 | M2hK5diA0N8pxwSwbi1ws | 78.88 | OI8B2wtJUXhqc7VEluyqcqcmjV7utVCUx | ±-----±--------±----------------------±--------±----------------------------------+ 1 row in set (0.00 sec) MySQL [test]> CREATE OUTLINE ol_2 ON SELECT /*+max_concurrent(1)*/ * from item where i_id = 1; Query OK, 0 rows affected (0.09 sec) h上面的操作对select * from item where i_id = 1; 限流不起作用 MySQL [test]> explain extended select * from item where i_id = 1; ±-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Query Plan | ±-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | ================================== |ID|OPERATOR |NAME|EST. ROWS|COST| ---------------------------------- |0 |TABLE GET|item|1 |53 | ================================== Outputs & filters: ------------------------------------- 0 - output([item.i_id(0x7ef59fdce8e0)], [item.i_im_id(0x7ef59fdceb70)], [item.i_name(0x7ef59fdcee00)], [item.i_price(0x7ef59fde9e10)], [item.i_data(0x7ef59fdea0a0)]), filter(nil), access([item.i_id(0x7ef59fdce8e0)], [item.i_im_id(0x7ef59fdceb70)], [item.i_name(0x7ef59fdcee00)], [item.i_price(0x7ef59fde9e10)], [item.i_data(0x7ef59fdea0a0)]), partitions(p0), is_index_back=false, range_key([item.i_id(0x7ef59fdce8e0)]), range[1 ; 1], range_cond([item.i_id(0x7ef59fdce8e0) = 1(0x7ef59fdce260)]) Used Hint: ------------------------------------- /*+ */ Outline Data: ------------------------------------- /*+ BEGIN_OUTLINE_DATA FULL(@“SEL$1” “test.item”@“SEL$1”) END_OUTLINE_DATA */ Plan Type: ------------------------------------- LOCAL Optimization Info: ------------------------------------- item:table_rows:100000, physical_range_rows:1, logical_range_rows:1, index_back_rows:0, output_rows:1, est_method:local_storage, optimization_method=rule_based, heuristic_rule=unique_index_without_indexback Parameters ------------------------------------- | ±-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec)

#2 
explain extended select * from item  where i_id = 1;


测试语句的大小写和空格，也就是说除了 /*+max_concurrent(1)*/ 其他部分要跟outline中的文本保持一致，