作为升级过程的一部分，Alfresco会执行此查询
INSERT INTO ACT_HI_VARINST(
ID_,
PROC_INST_ID_,
EXECUTION_ID_,
TASK_ID_,
NAME_,
VAR_TYPE_,
REV_,
BYTEARRAY_ID_,
DOUBLE_,
LONG_,
TEXT_,
TEXT2_
)
SELECT
(@cnt := @cnt + 1),
PROC_INST_ID_,
EXECUTION_ID_,
TASK_ID_,
NAME_,
VAR_TYPE_,
REV_,
BYTEARRAY_ID_,
DOUBLE_,
LONG_,
TEXT_,
TEXT2_
FROM ACT_HI_DETAIL AHD
CROSS JOIN (SELECT @cnt := 177401 + 1) AS dummy
WHERE AHD.PROC_INST_ID_ not in (select PROC_INST_ID_ from ACT_HI_VARINST)
AND
(AHD.PROC_INST_ID_ , AHD.NAME_, AHD.REV_, AHD.time_) IN
(SELECT PROC_INST_ID_, NAME_, MAX(REV_), MAX(time_)
FROM ACT_HI_DETAIL
GROUP BY PROC_INST_ID_ , NAME_);
运行需要12个多小时。
在查询上使用说明
explain SELECT
(@cnt := @cnt + 1),
PROC_INST_ID_,
EXECUTION_ID_,
TASK_ID_,
NAME_,
VAR_TYPE_,
REV_,
BYTEARRAY_ID_,
DOUBLE_,
LONG_,
TEXT_,
TEXT2_
FROM ACT_HI_DETAIL AHD
CROSS JOIN (SELECT @cnt := 177401 + 1) AS dummy
WHERE AHD.PROC_INST_ID_ not in (select PROC_INST_ID_ from ACT_HI_VARINST)
AND
(AHD.PROC_INST_ID_ , AHD.NAME_, AHD.REV_, AHD.time_) IN
(SELECT PROC_INST_ID_, NAME_, MAX(REV_), MAX(time_)
FROM ACT_HI_DETAIL
GROUP BY PROC_INST_ID_ , NAME_)\G
结果
*************************** 1. row ***************************
id: 1
select_type: PRIMARY
table: <derived2>
type: system
possible_keys: NULL
key: NULL
key_len: NULL
ref: NULL
rows: 1
Extra:
*************************** 2. row ***************************
id: 1
select_type: PRIMARY
table: AHD
type: ALL
possible_keys: ACT_IDX_HI_DETAIL_PROC_INST,ACT_IDX_HI_DETAIL_TIME,ACT_IDX_HI_DETAIL_NAME
key: NULL
key_len: NULL
ref: NULL
rows: 70669
Extra: Using where
*************************** 3. row ***************************
id: 1
select_type: PRIMARY
table: <subquery4>
type: eq_ref
possible_keys: distinct_key
key: distinct_key
key_len: 976
ref: alfresco.AHD.PROC_INST_ID_,alfresco.AHD.NAME_,alfresco.AHD.REV_,alfresco.AHD.TIME_
rows: 1
Extra:
*************************** 4. row ***************************
id: 4
select_type: MATERIALIZED
table: ACT_HI_DETAIL
type: ALL
possible_keys: NULL
key: NULL
key_len: NULL
ref: NULL
rows: 70669
Extra: Using temporary
*************************** 5. row ***************************
id: 3
select_type: MATERIALIZED
table: ACT_HI_VARINST
type: index
possible_keys: ACT_IDX_HI_PROCVAR_PROC_INST
key: ACT_IDX_HI_PROCVAR_PROC_INST
key_len: 197
ref: NULL
rows: 41504
Extra: Using index
*************************** 6. row ***************************
id: 2
select_type: DERIVED
table: NULL
type: NULL
possible_keys: NULL
key: NULL
key_len: NULL
ref: NULL
rows: NULL
Extra: No tables used
添加额外索引
ALTER TABLE ACT_HI_DETAIL ADD INDEX `ACT_HI_DETAIL_MULTI` (PROC_INST_ID_, TIME_, NAME_);
导致这里的行数减半
*************************** 2. row ***************************
id: 1
select_type: PRIMARY
table: AHD
type: range
possible_keys: act_hi_detail_multi_1
key: act_hi_detail_multi_1
key_len: 195
ref: NULL
rows: 35761
Extra: Using index condition; Using where
数据库正在使用innodb。
将innodb_buffer_pool_size设置为4G没有任何区别。
表格定义：
MariaDB [alfresco]> desc act_hi_detail;
+---------------+---------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------------+---------------+------+-----+---------+-------+
| ID_ | varchar(64) | NO | PRI | NULL | |
| TYPE_ | varchar(255) | NO | | NULL | |
| PROC_INST_ID_ | varchar(64) | YES | MUL | NULL | |
| EXECUTION_ID_ | varchar(64) | YES | | NULL | |
| TASK_ID_ | varchar(64) | YES | MUL | NULL | |
| ACT_INST_ID_ | varchar(64) | YES | MUL | NULL | |
| NAME_ | varchar(255) | NO | MUL | NULL | |
| VAR_TYPE_ | varchar(255) | YES | | NULL | |
| REV_ | int(11) | YES | | NULL | |
| TIME_ | datetime | NO | MUL | NULL | |
| BYTEARRAY_ID_ | varchar(64) | YES | | NULL | |
| DOUBLE_ | double | YES | | NULL | |
| LONG_ | bigint(20) | YES | | NULL | |
| TEXT_ | varchar(4000) | YES | | NULL | |
| TEXT2_ | varchar(4000) | YES | | NULL | |
+---------------+---------------+------+-----+---------+-------+
15 rows in set (0.00 sec)
MariaDB [alfresco]> desc act_hi_varinst;
+---------------+---------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------------+---------------+------+-----+---------+-------+
| ID_ | varchar(64) | NO | PRI | NULL | |
| PROC_INST_ID_ | varchar(64) | YES | MUL | NULL | |
| EXECUTION_ID_ | varchar(64) | YES | | NULL | |
| TASK_ID_ | varchar(64) | YES | | NULL | |
| NAME_ | varchar(255) | NO | MUL | NULL | |
| VAR_TYPE_ | varchar(100) | YES | | NULL | |
| REV_ | int(11) | YES | | NULL | |
| BYTEARRAY_ID_ | varchar(64) | YES | | NULL | |
| DOUBLE_ | double | YES | | NULL | |
| LONG_ | bigint(20) | YES | | NULL | |
| TEXT_ | varchar(4000) | YES | | NULL | |
| TEXT2_ | varchar(4000) | YES | | NULL | |
+---------------+---------------+------+-----+---------+-------+
12 rows in set (0.00 sec)
当前索引是
MariaDB [alfresco]> show indexes from act_hi_detail;
+---------------+------------+-----------------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+---------------+------------+-----------------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| act_hi_detail | 0 | PRIMARY | 1 | ID_ | A | 71244 | NULL | NULL | | BTREE | | |
| act_hi_detail | 1 | ACT_IDX_HI_DETAIL_PROC_INST | 1 | PROC_INST_ID_ | A | 3238 | NULL | NULL | YES | BTREE | | |
| act_hi_detail | 1 | ACT_IDX_HI_DETAIL_ACT_INST | 1 | ACT_INST_ID_ | A | 5937 | NULL | NULL | YES | BTREE | | |
| act_hi_detail | 1 | ACT_IDX_HI_DETAIL_TIME | 1 | TIME_ | A | 8905 | NULL | NULL | | BTREE | | |
| act_hi_detail | 1 | ACT_IDX_HI_DETAIL_NAME | 1 | NAME_ | A | 147 | NULL | NULL | | BTREE | | |
| act_hi_detail | 1 | ACT_IDX_HI_DETAIL_TASK_ID | 1 | TASK_ID_ | A | 5480 | NULL | NULL | YES | BTREE | | |
| act_hi_detail | 1 | act_hi_detail_multi_1 | 1 | PROC_INST_ID_ | A | 199 | NULL | NULL | YES | BTREE | | |
| act_hi_detail | 1 | act_hi_detail_multi_1 | 2 | TIME_ | A | 199 | NULL | NULL | | BTREE | | |
| act_hi_detail | 1 | act_hi_detail_multi_1 | 3 | NAME_ | A | 199 | NULL | NULL | | BTREE | | |
+---------------+------------+-----------------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
9 rows in set (0.01 sec)
MariaDB [alfresco]> show indexes from act_hi_varinst;
+----------------+------------+------------------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+----------------+------------+------------------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| act_hi_varinst | 0 | PRIMARY | 1 | ID_ | A | 42358 | NULL | NULL | | BTREE | | |
| act_hi_varinst | 1 | ACT_IDX_HI_PROCVAR_PROC_INST | 1 | PROC_INST_ID_ | A | 1925 | NULL | NULL | YES | BTREE | | |
| act_hi_varinst | 1 | ACT_IDX_HI_PROCVAR_NAME_TYPE | 1 | NAME_ | A | 184 | NULL | NULL | | BTREE | | |
| act_hi_varinst | 1 | ACT_IDX_HI_PROCVAR_NAME_TYPE | 2 | VAR_TYPE_ | A | 219 | NULL | NULL | YES | BTREE | | |
+----------------+------------+------------------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
4 rows in set (0.01 sec)
是否可以添加或修改可以对查询进行更多索引以大大提高速度？