Online DDL 是否锁表、是否rebuild表、inplace或copy算法的说明：
原文： https://dev.mysql.com/doc/refman/5.6/en/innodb-create-index-overview.html?spm=5176.100239.blogcont64664.13.SpL8lH
| Operation | In-Place? | Rebuilds Table? | Permits Concurrent DML? | Only Modifies Metadata? | Notes |
|---|---|---|---|---|---|
CREATE INDEX, ADD INDEX | Yes* | No* | Yes | No | Restrictions apply for FULLTEXT indexes; see next row. |
ADD FULLTEXT INDEX | Yes* | No* | No | No | Adding the first FULLTEXT index rebuilds the table if there is no user-defined FTS_DOC_ID column. Subsequent FULLTEXT indexes may be added on the same table without rebuilding the table. |
DROP INDEX | Yes | No | Yes | Yes | Only modifies table metadata. |
OPTIMIZE TABLE | Yes* | Yes | Yes | No | Performed in-place as of MySQL 5.6.17. In-place operation is not supported for tables withFULLTEXT indexes. |
| Set column default value | Yes | No | Yes | Yes | Only modifies table metadata. |
| Change auto-incrementvalue | Yes | No | Yes | No* | Modifies a value stored in memory, not the data file. |
| Add foreign key constraint | Yes* | No | Yes | Yes | The INPLACE algorithm is supported when foreign_key_checks is disabled. Otherwise, only theCOPY algorithm is supported. |
| Drop foreign key constraint | Yes | No | Yes | Yes | foreign_key_checks can be enabled or disabled. |
| Rename column | Yes | No | Yes* | Yes | To permit concurrent DML, keep the same data type and only change the column name. |
| Add column | Yes | Yes | Yes* | No | Concurrent DML is not permitted when adding an auto-increment column. Data is reorganized substantially, making it an expensive operation. |
| Drop column | Yes | Yes | Yes | No | Data is reorganized substantially, making it an expensive operation. |
| Reorder columns | Yes | Yes | Yes | No | Data is reorganized substantially, making it an expensive operation. |
Change ROW_FORMATproperty | Yes | Yes | Yes | No | Data is reorganized substantially, making it an expensive operation. |
Change KEY_BLOCK_SIZEproperty | Yes | Yes | Yes | No | Data is reorganized substantially, making it an expensive operation. |
Make column NULL | Yes | Yes* | Yes | No | Rebuilds the table in place. Data is reorganized substantially, making it an expensive operation. |
Make column NOT NULL | Yes* | Yes* | Yes | No | Rebuilds the table in place. STRICT_ALL_TABLES or STRICT_TRANS_TABLES SQL_MODE is required for the operation to succeed. The operation fails if the column contains NULL values. As of 5.6.7, the server prohibits changes to foreign key columns that have the potential to cause loss of referential integrity. See Section 13.1.7, “ALTER TABLE Syntax”. Data is reorganized substantially, making it an expensive operation. |
| Change column data type | No | Yes | No | No | Only supports ALGORITHM=COPY |
| Add primary key | Yes* | Yes* | Yes | No | Rebuilds the table in place. Data is reorganized substantially, making it an expensive operation.ALGORITHM=INPLACE is not permitted under certain conditions if columns have to be converted toNOT NULL. |
| Drop primary key and add another | Yes | Yes | Yes | No | Data is reorganized substantially, making it an expensive operation. |
| Drop primary key | No | Yes | No | No | Only ALGORITHM=COPY supports dropping a primary key without adding a new one in the sameALTER TABLE statement. |
| Convert character set | No | Yes* | No | No | Rebuilds the table if the new character encoding is different. |
| Specify character set | No | Yes* | No | No | Rebuilds the table if the new character encoding is different. |
Rebuild with FORCEoption | Yes* | Yes | Yes | No | Uses ALGORITHM=INPLACE as of MySQL 5.6.17. ALGORITHM=INPLACE is not supported for tables withFULLTEXT indexes. |
“null” rebuild usingALTER TABLE ... ENGINE=INNODB | Yes* | Yes | Yes | No | Uses ALGORITHM=INPLACE as of MySQL 5.6.17. ALGORITHM=INPLACE is not supported for tables withFULLTEXT indexes. |
Set STATS_PERSISTENT,STATS_AUTO_RECALC,STATS_SAMPLE_PAGESpersistent statisticsoptions | Yes | No | Yes | Yes | Only modifie |
其余可参考文章： https://yq.aliyun.com/articles/64664
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