如何使用CHECK GLOBAL INDEX语句检查数据一致性_云原生数据库 PolarDB(PolarDB)-阿里云帮助中心

您可以使用CHECK GLOBAL INDEX语句检查主表和索引表的数据是否完全一致，并修订不一致的数据。

语法

CHECK GLOBAL INDEX gsi_name [ON tbl_name] [extra_cmd]


参数	说明
`gsi_name`	需要校验的全局二级索引名。
`tbl_name`	全局二级索引所在的主表，非必选。若您输入具体主表名称，将会检查全局二级索引表和主表间的索引关系是否正确。
`extra_cmd`	保留的额外指令，目前支持如下指令： -：不指定任何关键字时，即表示仅检查全局二级索引。 SHOW：显示指定GSI表的最近一次校验或订正的结果。 CORRECTION_BASED_ON_PRIMARY：对全局二级索引表中的数据进行订正，以主表为基准。

说明

对全局二级索引表中的数据进行校验或订正时会占用一定的系统资源，特别是订正操作会对主表或索引表内数据分批加锁并订正，建议您在业务低谷期进行操作。更多关于GSI的使用方式，请参见使用全局二级索引。
对大表的GSI校验可能会花费较多的时间，可以使用HINT指定PURE_ASYNC_DDL_MODE，以纯异步模式执行DDL语句，请参见控制参数与行为。

示例

您可以使用如下语句进行校验：

mysql> CHECK GLOBAL INDEX `g_i_check`;

若校验没有发现错误，则返回如下结果：

+-------------+------------+--------+-------------+-----------------------------+
| GSI_TABLE   | ERROR_TYPE | STATUS | PRIMARY_KEY | DETAILS                     |
+-------------+------------+--------+-------------+-----------------------------+
| `g_i_check` | SUMMARY    | --     | --          | OK (7025/7025 rows checked) |
+-------------+------------+--------+-------------+-----------------------------+
1 row in set (1.40 sec)

若校验发现错误，则返回如下结果：

+-------------+------------+--------+-------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| GSI_TABLE   | ERROR_TYPE | STATUS | PRIMARY_KEY | DETAILS                                                                                                                                                                                                                                                                                                                                                                                        |
+-------------+------------+--------+-------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| `g_i_check` | ORPHAN     | FOUND  | (100722)    | {"GSI":{"id":100722,"c_timestamp_6":"2000-01-01 00:00:00.000000","c_timestamp_3":"2000-01-01 00:00:00.000","c_timestamp_1":"2000-01-01 00:00:00.0","c_binary":"OTkAAAAAAAAAAA==","c_int_32":271}}                                                                                                                                                                                              |
| `g_i_check` | CONFLICT   | FOUND  | (108710)    | {"Primary":{"id":108710,"c_timestamp_6":"2000-01-01 00:00:00.000000","c_timestamp_3":"2000-01-01 00:00:00.000","c_timestamp_1":"2000-01-01 00:00:00.0","c_year":"2000","c_int_32":255},"GSI":{"c_int_32_un":123456,"id":108710,"c_timestamp_6":"2000-01-01 00:00:00.000000","c_timestamp_3":"2000-01-01 00:00:00.000","c_timestamp_1":"2000-01-01 00:00:00.0","c_year":"2000","c_int_32":255}} |
| `g_i_check` | MISSING    | FOUND  | (100090)    | {"Primary":{"id":100090,"c_timestamp_6":"2000-01-01 00:00:00.000000","c_timestamp_3":"2000-01-01 00:00:00.000","c_timestamp_1":"2000-01-01 00:00:00.0","c_blob_tiny":"YeS4reWbvWE=","c_int_32":280}}                                                                                                                                                                                           |
| `g_i_check` | SUMMARY    | --     | --          | 3 error found (7025/7025 rows checked)                                                                                                                                                                                                                                                                                                                                                         |
+-------------+------------+--------+-------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
4 rows in set (1.92 sec)

说明如果数据存在多种错误，同一行数据会报多个ERROR_TYPE值。

您可以使用如下语句进行订正：

mysql> CHECK GLOBAL INDEX g_i_check CORRECTION_BASED_ON_PRIMARY;

返回结果如下：

+-------------+------------+--------+-------------+------------------------------------------------------------------------+
| GSI_TABLE   | ERROR_TYPE | STATUS | PRIMARY_KEY | DETAILS                                                                |
+-------------+------------+--------+-------------+------------------------------------------------------------------------+
| `g_i_check` | SUMMARY    | --     | --          | Done. Use SQL: { CHECK GLOBAL INDEX `g_i_check` SHOW; } to get result. |
+-------------+------------+--------+-------------+------------------------------------------------------------------------+
1 row in set (1.40 sec)

您可以使用如下语句查看最近一次校验或订正的报告：

mysql> CHECK GLOBAL INDEX `g_i_check` SHOW;

返回结果如下：

+-------------+------------+----------+-------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| GSI_TABLE   | ERROR_TYPE | STATUS   | PRIMARY_KEY | DETAILS                                                                                                                                                                                                                                                                                                                                                                                        |
+-------------+------------+----------+-------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| `g_i_check` | MISSING    | REPAIRED | (100090)    | {"Primary":{"id":100090,"c_timestamp_6":"2000-01-01 00:00:00.000000","c_timestamp_3":"2000-01-01 00:00:00.000","c_timestamp_1":"2000-01-01 00:00:00.0","c_blob_tiny":"YeS4reWbvWE=","c_int_32":280}}                                                                                                                                                                                           |
| `g_i_check` | CONFLICT   | REPAIRED | (108710)    | {"Primary":{"id":108710,"c_timestamp_6":"2000-01-01 00:00:00.000000","c_timestamp_3":"2000-01-01 00:00:00.000","c_timestamp_1":"2000-01-01 00:00:00.0","c_year":"2000","c_int_32":255},"GSI":{"c_int_32_un":123456,"id":108710,"c_timestamp_6":"2000-01-01 00:00:00.000000","c_timestamp_3":"2000-01-01 00:00:00.000","c_timestamp_1":"2000-01-01 00:00:00.0","c_year":"2000","c_int_32":255}} |
| `g_i_check` | ORPHAN     | REPAIRED | (100722)    | {"GSI":{"id":100722,"c_timestamp_6":"2000-01-01 00:00:00.000000","c_timestamp_3":"2000-01-01 00:00:00.000","c_timestamp_1":"2000-01-01 00:00:00.0","c_binary":"OTkAAAAAAAAAAA==","c_int_32":271}}                                                                                                                                                                                              |
| `g_i_check` | SUMMARY    | --       | --          | 3 error found (7025/7026 rows checked.) Finish time: 2020-01-13 14:41:51.0                                                                                                                                                                                                                                                                                                                     |
+-------------+------------+----------+-------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
4 rows in set (0.02 sec)

表 1. 列名说明
列名	说明
GSI_TABLE	全局二级索引名。
ERROR_TYPE	错误类型，取值范围如下： MISSING：索引丢失 ORPHAN：孤儿索引 CONFLICT：索引数据不一致 ERROR_SHARD：数据分片位置错误 SUMMARY：结果汇总
STATUS	状态，取值范围如下： FOUND：发现错误 REPAIRED：已修复
PRIMARY_KEY	主键。
DETAILS	错误的详细信息。