How does create index and DROP INDEX work in InnoDB?
When we are adding or dropping a secondary index, internally It scans the table, and sorts the rows using memory buffers in order by the values of the secondary index key columns. Once a CREATE INDEX or ALTER TABLE statement starts to create InnoDB secondary index, we can only read the table, but cannot update the table.
Why is the InnoDB table still in MySQL?
InnoDB: This may also be a table created with CREATE TEMPORARY TABLE InnoDB: whose .ibd and .frm files MySQL automatically removed, but the InnoDB: table still exists in the InnoDB internal data dictionary. If this occurs, try the following procedure to resolve the problem:
How does MySQL increase the performance of CREATE INDEX and DROP INDEX?
In MySQL 5.5 and higher version, Index performance has improved a lot. MySQL InnoDB engine has basically two types of index, Primary clustered index and Secondary indexes. When we are adding or dropping a clustered index, It is copying the data, and creating a new copy of the table.
What is the error message for the InnoDB data dictionary?
[ERROR] InnoDB: Cannot open datafile for read-only: ‘./test/t1.ibd’ OS error: 71 [Warning] InnoDB: Ignoring tablespace `test/t1` because it could not be opened. To address these messages, issue DROP TABLE statement to remove data about the missing table from the data dictionary.
Which is the fastest ALTER TABLE for InnoDB database?
Just use ALTER TABLE as usual, it’ll be mostly instant for renames and index drops, and reasonably fast for index addition (as fast as reading all the table once). If using 5.1+, and the InnoDB plugin is enabled, adding/removing indices will be online as well.
How are indexes used in MySQL 8.0 reference manual?
To tune queries for InnoDB tables, create an appropriate set of indexes on each table. See Section 8.3.1, “How MySQL Uses Indexes” for details. Follow these guidelines for InnoDB indexes: