Are MySQL Multi-column master keys an optimization issue?

Question

Studying the use of primary keys with multiple columns, and since performance is extremely important with the size of the traffic and the database, I need to know if there is anything to consider before I start throwing away a unique ID method on many of my tables and start using primary keys mulit column.

So, what are the advantages / disadvantages of performance / optimization for using the primary keys of multiple columns compared to the base single column, the auto-inc primary key?

Answer 1

I would not have thought that there would be performance issues with multiple primary keys. This is more or less equivalent to having multiple indexes (when inserting, you spend a little more time calculating the index values).

Sometimes a data model makes more sense with multiple keys. I would take care to be the first and worry about performance secondly. You can always add more indexes, improve your queries or change server settings.

I think that most of all I came across a 4-column primary key. Makes me cringe a little, but it worked & sup1 ;.

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[1] “worked” is defined as “an application executed for specification” and does not imply that actual tasks were performed using the application. :)

Answer 2

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HTH -