Looker allows users to set row and column limits when they are exploring. Column limits are useful when users are working with pivoted datasets. You can read more pivoting on this docs page and more about limits on this docs page.
Column limits are associated with the Row Limit Only legacy feature (for more details see the Legacy Features docs page):
- From release 3.16 to 4.18, the legacy feature is on by default, which means that you will only have access to row limits
- From release 4.20 to 4.22, the legacy feature is off by default, which means you also have access to column limits
- As of release 5.0, column limits are always on
Before an explicit column limit was available, users only had access to a row limit when exploring data. If they had pivoted their data, Looker would apply the row limit to the user’s query, then it would pivot that result set. This could be confusing because the number of rows in the pivoted dataset would not match the row limit they had set. Also, the user might not get all the column values they expected if they hadn’t set a high enough row limit.
With the explicit column limit added, the explore experience in Looker matches the behavior that users would expect. The row limit now restricts the number of rows in the final result set, and the column limit restricts the number of pivoted columns in the final result set.