Re: Why does MySQL create a temp table when adding an index?

At 09:07 PM 12/10/2003, you wrote: Hi There, The data needs to be sorted into the key you specified. Any RDBMS does this type of operation. Some don;t copy the whole table though, just the columns you are indexing Cheers Chris Chris, Ok, I see your point. Some of the other database

Why does MySQL create a temp table when adding an index?

I don't understand why MySQL will create a copy of the table when I'm adding an index to it. Example: Alter Table Tablex Add Index NewIndex (col1,col2); ProcessList will show "copy to tmp table" for 99% of the process. This will physically copy the data to a temporary table. I have a 7gb table