在StoneDB中，資料包分為以下幾類：

不相關的資料包：不滿足查詢條件的資料包，
相關的資料包：滿足查詢條件的資料包，
可疑的資料包：資料包中的資料部分滿足查詢條件，需要進一步解壓縮資料包才能得到滿足條件的資料行，

通過對資料包的劃分，知識網格技術過濾掉不相關的資料包，讀取相關的資料包和可疑的資料包，其中相關的資料包不需要解壓縮，只讀取元資料，不會發生IO，可疑的資料包需要解壓縮，會發生IO，

1）創建表t_user
CREATE TABLE t_user(
  id INT NOT NULL AUTO_INCREMENT,
  first_name VARCHAR(10) NOT NULL,
  last_name VARCHAR(10) NOT NULL,
  sex VARCHAR(5) NOT NULL,
  score INT NOT NULL,
  copy_id INT NOT NULL,
  PRIMARY KEY (`id`),
  key idx_lastname(last_name)
) engine=STONEDB;

2）創建存盤程序
DELIMITER //
    create PROCEDURE add_user(in num INT)
    BEGIN
        DECLARE rowid INT DEFAULT 0;
        DECLARE firstname CHAR(1);
        DECLARE name1 CHAR(1);
        DECLARE name2 CHAR(1);
        DECLARE lastname VARCHAR(3) DEFAULT '';
        DECLARE sex CHAR(1);
        DECLARE score CHAR(2);
        WHILE rowid < num DO
        SET firstname = SUBSTRING('趙錢孫李周吳鄭王林楊柳劉孫陳江阮侯鄒高彭徐',FLOOR(1+21*RAND()),1); 
        SET name1 = SUBSTRING('一二三四五六七八九十甲乙丙丁靜景京晶名明銘敏閔民軍君俊駿天田甜兲恬益依成城誠立莉力黎勵',ROUND(1+43*RAND()),1); 
        SET name2 = SUBSTRING('一二三四五六七八九十甲乙丙丁靜景京晶名明銘敏閔民軍君俊駿天田甜兲恬益依成城誠立莉力黎勵',ROUND(1+43*RAND()),1); 
        SET sex=FLOOR(0 + (RAND() * 2));
        SET score= FLOOR(40 + (RAND() *60));
        SET rowid = rowid + 1;
        IF ROUND(RAND())=0 THEN 
        SET lastname =name1;
        END IF;
        IF ROUND(RAND())=1 THEN
        SET lastname = CONCAT(name1,name2);
        END IF;
        insert INTO t_user(first_name,last_name,sex,score,copy_id) VALUES (firstname,lastname,sex,score,rowid);  
        END WHILE;
    END //
DELIMITER ;

3）插入資料
call add_user(10000000);

4）創建表t_user_innodb
create table t_user_innodb like t_user;
insert into t_user_innodb select * from t_user;
alter table t_user_innodb engine=innodb;

1）驗證讀取相關資料包

SQL的語意邏輯是對欄位 first_name 進行分組統計，在StoneDB中，元資料資訊記錄在元資料節點，如果能通過元資料節點讀取到元資料，就不需要解壓縮資料包，不發生IO，
在InnoDB中，表的統計資訊記錄在mysql.innodb_table_stats，優化器根據表和索引的統計資訊，生成一個最優的執行計劃，然后執行SQL，分別在InnoDB與StoneDB執行，通過SQL profile觀察讀取IO的情況，
注：為規避快取的影響，每組測驗前重啟資料庫實體，

InnoDB

mysql> set profiling=on;                                          
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> select first_name,count(*) from t_user_innodb group by first_name;
+------------+----------+
| first_name | count(*) |
+------------+----------+
| 侯         |   476424 |
| 劉         |   475764 |
| 吳         |   475979 |
| 周         |   475891 |
| 孫         |   950444 |
| 彭         |   476632 |
| 徐         |   476219 |
| 李         |   475521 |
| 楊         |   476026 |
| 林         |   477289 |
| 柳         |   476250 |
| 江         |   476623 |
| 王         |   475119 |
| 趙         |   476529 |
| 鄒         |   476852 |
| 鄭         |   476379 |
| 錢         |   476829 |
| 阮         |   476336 |
| 陳         |   476746 |
| 高         |   476148 |
+------------+----------+
20 rows in set (8.62 sec)

mysql> show profiles;                                                    
+----------+------------+-------------------------------------------------------------------+
| Query_ID | Duration   | Query                                                             |
+----------+------------+-------------------------------------------------------------------+
|        1 | 8.61591075 | select first_name,count(*) from t_user_innodb group by first_name |
+----------+------------+-------------------------------------------------------------------+
1 row in set, 1 warning (0.00 sec)

mysql> show profile cpu,block io for query 1;                            
+----------------------+----------+----------+------------+--------------+---------------+
| Status               | Duration | CPU_user | CPU_system | Block_ops_in | Block_ops_out |
+----------------------+----------+----------+------------+--------------+---------------+
| starting             | 0.000149 | 0.000059 |   0.000083 |            0 |             0 |
| checking permissions | 0.000027 | 0.000011 |   0.000015 |            0 |             0 |
| Opening tables       | 0.048181 | 0.003919 |   0.007952 |          608 |             0 |
| init                 | 0.000036 | 0.000014 |   0.000021 |            0 |             0 |
| System lock          | 0.000022 | 0.000009 |   0.000013 |            0 |             0 |
| optimizing           | 0.000017 | 0.000007 |   0.000010 |            0 |             0 |
| statistics           | 0.000029 | 0.000012 |   0.000016 |            0 |             0 |
| preparing            | 0.000022 | 0.000009 |   0.000013 |            0 |             0 |
| Creating tmp table   | 0.000045 | 0.000019 |   0.000027 |            0 |             0 |
| Sorting result       | 0.000016 | 0.000007 |   0.000009 |            0 |             0 |
| executing            | 0.000014 | 0.000005 |   0.000008 |            0 |             0 |
| Sending data         | 8.566974 | 6.905969 |   0.772964 |       873888 |             0 |
| Creating sort index  | 0.000144 | 0.000164 |   0.000037 |           64 |             0 |
| end                  | 0.000014 | 0.000012 |   0.000003 |           32 |             0 |
| query end            | 0.000028 | 0.000038 |   0.000009 |            0 |             0 |
| removing tmp table   | 0.000019 | 0.000015 |   0.000003 |            0 |             0 |
| query end            | 0.000012 | 0.000010 |   0.000002 |            0 |             0 |
| closing tables       | 0.000031 | 0.000025 |   0.000006 |            0 |             0 |
| freeing items        | 0.000032 | 0.000027 |   0.000006 |            0 |             0 |
| logging slow query   | 0.000067 | 0.000054 |   0.000012 |            0 |             8 |
| cleaning up          | 0.000035 | 0.000028 |   0.000006 |            0 |             0 |
+----------------------+----------+----------+------------+--------------+---------------+
21 rows in set, 1 warning (0.00 sec)

從SQL profile可知，SQL在InnoDB執行的程序中，發生IO的階段有Opening tables、Sending data、Creating sort index、end，其中Opening tables是每張表第一次加載都會經歷的，可排除討論，重點關注Sending data部分，它表示在執行器的任意階段，通常是存盤引擎層與Server層的IO互動程序，

StoneDB

mysql> set profiling=on;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> select first_name,count(*) from t_user group by first_name;
+------------+----------+
| first_name | count(*) |
+------------+----------+
| 趙         |   476529 |
| 徐         |   476219 |
| 王         |   475119 |
| 阮         |   476336 |
| 柳         |   476250 |
| 侯         |   476424 |
| 孫         |   950444 |
| 鄭         |   476379 |
| 高         |   476148 |
| 林         |   477289 |
| 鄒         |   476852 |
| 彭         |   476632 |
| 李         |   475521 |
| 吳         |   475979 |
| 劉         |   475764 |
| 錢         |   476829 |
| 周         |   475891 |
| 楊         |   476026 |
| 陳         |   476746 |
| 江         |   476623 |
+------------+----------+
20 rows in set (0.59 sec)

mysql> show profiles;
+----------+------------+------------------------------------------------------------+
| Query_ID | Duration   | Query                                                      |
+----------+------------+------------------------------------------------------------+
|        1 | 0.59069975 | select first_name,count(*) from t_user group by first_name |
+----------+------------+------------------------------------------------------------+
1 row in set, 1 warning (0.00 sec)

mysql> show profile cpu,block io for query 1;
+----------------------+----------+----------+------------+--------------+---------------+
| Status               | Duration | CPU_user | CPU_system | Block_ops_in | Block_ops_out |
+----------------------+----------+----------+------------+--------------+---------------+
| starting             | 0.000160 | 0.000066 |   0.000089 |            0 |             0 |
| checking permissions | 0.000027 | 0.000011 |   0.000015 |            0 |             0 |
| Opening tables       | 0.011405 | 0.003718 |   0.007688 |            0 |           240 |
| System lock          | 0.000385 | 0.000163 |   0.000222 |            0 |             0 |
| init                 | 0.000050 | 0.000021 |   0.000028 |            0 |             0 |
| optimizing           | 0.000143 | 0.000061 |   0.000082 |            0 |             0 |
| update multi-index   | 0.000052 | 0.000022 |   0.000030 |            0 |             0 |
| aggregation          | 0.578315 | 2.639504 |   0.981471 |            0 |             8 |
| query end            | 0.000069 | 0.000043 |   0.000026 |            0 |             0 |
| closing tables       | 0.000035 | 0.000021 |   0.000013 |            0 |             0 |
| freeing items        | 0.000034 | 0.000021 |   0.000013 |            0 |             0 |
| cleaning up          | 0.000027 | 0.000017 |   0.000010 |            0 |             0 |
+----------------------+----------+----------+------------+--------------+---------------+
12 rows in set, 1 warning (0.00 sec)

從SQL profile可知，SQL在StoneDB執行的程序中，只在Opening tables階段發生IO，其它階段沒有發生IO，說明相關資料包是不需要解壓縮的，通過元資料得到，

2）驗證讀取可疑資料包

SQL的語意邏輯是查詢一行資料，StoneDB可以通過知識網格技術過濾掉不相關的資料包，由于只回傳一行資料，最終只能找到可疑的資料包，然后解壓縮可疑的資料包，最終得到這一行資料，InnoDB還是根據統計資訊生成一個最優的執行計劃去執行SQL，

InnoDB

mysql> set profiling=on;                              
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> select count(*) from t_user_innodb where first_name='柳' and copy_id=9968888;
+----------+
| count(*) |
+----------+
|        1 |
+----------+
1 row in set (3.20 sec)

mysql> show profile cpu,block io for query 1;
+----------------------+----------+----------+------------+--------------+---------------+
| Status               | Duration | CPU_user | CPU_system | Block_ops_in | Block_ops_out |
+----------------------+----------+----------+------------+--------------+---------------+
| starting             | 0.000170 | 0.000072 |   0.000092 |            0 |             0 |
| checking permissions | 0.000030 | 0.000013 |   0.000016 |            0 |             0 |
| Opening tables       | 0.024121 | 0.004351 |   0.008638 |          800 |             0 |
| init                 | 0.000049 | 0.000021 |   0.000027 |            0 |             0 |
| System lock          | 0.000019 | 0.000008 |   0.000011 |            0 |             0 |
| optimizing           | 0.000022 | 0.000010 |   0.000012 |            0 |             0 |
| statistics           | 0.000030 | 0.000013 |   0.000016 |            0 |             0 |
| preparing            | 0.000026 | 0.000012 |   0.000015 |            0 |             0 |
| executing            | 0.000013 | 0.000005 |   0.000007 |            0 |             0 |
| Sending data         | 3.169882 | 2.755171 |   0.389367 |       534176 |             0 |
| end                  | 0.000069 | 0.000050 |   0.000018 |            0 |             0 |
| query end            | 0.000029 | 0.000022 |   0.000008 |            0 |             0 |
| closing tables       | 0.000031 | 0.000023 |   0.000009 |            0 |             0 |
| freeing items        | 0.000035 | 0.000025 |   0.000009 |            0 |             0 |
| cleaning up          | 0.000038 | 0.000028 |   0.000010 |            0 |             0 |
+----------------------+----------+----------+------------+--------------+---------------+
15 rows in set, 1 warning (0.00 sec)

StoneDB

mysql> set profiling=on;                                                            
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> select count(*) from t_user where first_name='柳' and copy_id=9968888;
+----------+
| count(*) |
+----------+
|        1 |
+----------+
1 row in set (0.01 sec)

mysql> show profile cpu,block io for query 1;                                
+----------------------+----------+----------+------------+--------------+---------------+
| Status               | Duration | CPU_user | CPU_system | Block_ops_in | Block_ops_out |
+----------------------+----------+----------+------------+--------------+---------------+
| starting             | 0.000173 | 0.000081 |   0.000086 |            0 |             0 |
| checking permissions | 0.000026 | 0.000013 |   0.000013 |            0 |             0 |
| Opening tables       | 0.010228 | 0.009385 |   0.000843 |            0 |           240 |
| System lock          | 0.000232 | 0.000113 |   0.000119 |            0 |             0 |
| init                 | 0.000045 | 0.000021 |   0.000022 |            0 |             0 |
| optimizing           | 0.000144 | 0.000071 |   0.000074 |            0 |             0 |
| update multi-index   | 0.003694 | 0.002027 |   0.006428 |            0 |             0 |
| aggregation          | 0.000191 | 0.000093 |   0.000098 |            0 |            16 |
| query end            | 0.000020 | 0.000010 |   0.000010 |            0 |             0 |
| closing tables       | 0.000029 | 0.000014 |   0.000015 |            0 |             0 |
| freeing items        | 0.000033 | 0.000016 |   0.000017 |            0 |             0 |
| cleaning up          | 0.000027 | 0.000013 |   0.000013 |            0 |             0 |
+----------------------+----------+----------+------------+--------------+---------------+
12 rows in set, 1 warning (0.00 sec)

從SQL profile可知，SQL在StoneDB執行的程序中，在aggregation階段發生IO，
綜上所述：

知識網格技術過濾出相關的資料包后，只需要讀取元資料，不再解壓縮資料包；
知識網格技術過濾出可疑的資料包后，需要解壓縮資料包，

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【StoneDB技術決議】驗證相關資料包是否需要解壓縮

1）驗證讀取相關資料包

InnoDB

StoneDB

2）驗證讀取可疑資料包

InnoDB

StoneDB