【问题描述】：tidb执行SQL语句导致drainer意外退出。drainer下游为MySQL8.0.18，执行的SQL语句为：DROP TABLE IF EXISTS student;
CREATE TABLE **student** ( student_id varchar(36) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL COMMENT ‘学生编号’, student_code varchar(36) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL COMMENT ‘学生编码’, student_name varchar(200) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL COMMENT ‘学生名称’, student_type_id varchar(36) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL COMMENT ‘分类编号’,
PRIMARY KEY (student_id) USING BTREE,
UNIQUE INDEX ak_key_2(student_code, student_name) USING BTREE,
INDEX idx_report_type_id(student_type_id) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_bin COMMENT = ‘学生定义’ ROW_FORMAT = Compact;
您好，
关于您的问题在官方文档中有具体回复：
Prefix support and lengths of prefixes (where supported) are storage engine dependent. For example, a prefix can be up to 767 bytes long for InnoDB tables or 3072 bytes if the innodb_large_prefix option is enabled. For MyISAM tables, the prefix length limit is 1000 bytes.