MySQL primary key column type for large tables

When you create a column as BIGINT(44) the "44" is the display width - it does not affect the range of values you can store or the speed at which they are retrieved.

For an auto-incrementing ID you want to use an UNSIGNED number, e.g. BIGINT(44) UNSIGNED. This will double the range of values and add an extra constraint, which is usually a good thing.

An unsigned INT will store up to:

4,294,967,295

An unsigned BIGINT will store up to:

18,446,744,073,709,551,615

you're not going to fill that any time soon.

You don't say how fast your maximum ID is growing - if you're not inserting many rows then you should stick with UNSIGNED INT as it takes less space.