Currently creating index by alter table add index ... will scan table one pass for each index, this waste cpu time if there are multi indexes are created in one statement.
It is possible to scan table one pass for all indexes in the alter table statement, especially if the table row is big, the performance improvements should be great.
Currently creating index by
alter table add index ...will scan table one pass for each index, this waste cpu time if there are multi indexes are created in one statement.It is possible to scan table one pass for all indexes in the alter table statement, especially if the table row is big, the performance improvements should be great.