Re: Number of Columns and Update

On 12/22/2014 03:53 PM, Robert DiFalco wrote:
> This may fall into the category of over-optimization but I've become
> curious.
>
> I have a user table with about 14 columns that are all 1:1 data - so
> they can't be normalized.
>
> When I insert a row all columns need to be set. But when I update, I
> sometimes only update 1-2 columns at a time. Does the number of
> columns impact update speed?
>
> For example:
>      UPDATE users SET email = ? WHERE id = ?;
>
> I can easily break this up into logical tables like user_profile,
> user_credential, user_contact_info, user_summary, etc with each table
> only having 1-4 columns. But with the multiple tables I would often be
> joining them to bring back a collection of columns.
>
> I know I'm over thinking this but I'm curious of what the performance
> trade offs are for breaking up a table into smaller logically grouped
> tables.
>
>

An update rewrites the whole row, not just the updated columns.

I think you are overthinking it.

cheers

andrew