与Copy Table方式相比,Online Add Index采用的是Inplace方式,无需Copy Table,减少了空间开销;与此同时,Online Add Index只有在重放Row Log最后一个Block时锁表,减少了锁表的时间。 与Inplace方式相比,Online Add Index吸收了Inplace方式的优势,却减少了锁表的时间。 Inplace add Index 本章节,主要通过测试/源码跟...
/* Index is not used in both parts of the WHERE clause */ ... WHERE index=1 OR A=10 /* No index spans all rows */ ... WHERE index_part1=1 OR index_part2=10 1. 2. 3. 4. 5. 6. 有时MySQL不使用索引,即使有可用的索引。一种情形是当优化器估计到使用索引将需要MySQL访问表中的...
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I am having trouble while adding index on mysql table with ndbcluster storage engine below is the error . [mysqlcluster ver. 7.4 GA] mysql> alter table `sks_staff_office` add index `pid_index` (pid); ERROR 1296 (HY000): Got error 156 'Unknown error code' from NDBCLUSTER ...
INDEX_NAME, '` USING ', INDEX_TYPE )END,IF(UPPER(INDEX_NAME) = 'PRIMARY', CONCAT('PRIMARY KEY USING ', INDEX_TYPE ),CONCAT('UNIQUE INDEX `', INDEX_NAME, '` USING ', INDEX_TYPE))),'(', GROUP_CONCAT(DISTINCT CONCAT('`', COLUMN_NAME, '`') ORDER BY SEQ_IN_INDEX ASC SEPARATO...
(col1, col2);" creates one index with two key parts. The key part is a reference to a column in the table, and for STRING/BINARY/TEXT/BLOB columns it is possible to only prefix a part of the column by specifying a prefix in parentheses after the column name; "CREATE INDEX idx1 ...
} else if (index->table->has_instant_cols()) { // 到这里说明record 上面 没有row_version DD 和 instant add 标记, 但是这个index 上面有instant add 标记 // 说明这个record 是instant add 之前就插入的 rec_insert_state = INSERTED_BEFORE_INSTANT_ADD_OLD_IMPLEMENTATION; ...
/* Record was inserted after first instant add/drop done in the newimplementation. */INSERTED_AFTER_INSTANT_ADD_NEW_IMPLEMENTATION,/* Record belongs to table with no verison no instant */// 如果index 上面没有做过instant add 或者 最新的row_version 版本Instant add/dropINSERTED_INTO_TABLE_WITH_...
MySQL从系统表读取表定义时,会将instant column相关的信息载入到InnoDB的表对象dict_table_t和索引对象dict_index_t中。 dict_table_t::n_instant_cols: 第一次instant add column之前的非虚拟字段个数(包含系统列), 具体过程详见函数dd_fill_dict_table ...
add index Posted by:Adrian Cazan Date: November 25, 2010 07:20AM Hello, I'm trying to add an index to a table. ALTER TABLE T ADD INDEX(aaa); The err message is: 1121 table handler doesn't support NULL in given index. Please change column 'aaa' to be NOT NULL or use another ...