What does Index scan (all rows) mean?

[MCMartin]

Index Scan Scan MYTable using index FK_1 (all rows)

Will this mean, that SQLA uses the foreign key but will still read all rows of the table?

[VolkerBarth]

Is that an IndexOnly scan (i.e. one that would not need to read additional table pages)?

[MCMartin]

no, it will have to read also non indexed columns, anyway the restriction through the index would already restrict the rows which have to be visited at all.