Update Index for Ferry Layers

[Nakaner]

Pull request #3727 introduced the new condition osm_id > 0 but did not update the condition for the indexes inteded to be used by the SQL queries of these layers.

[pnorman]

The old index will still work. I wouldn't expect many ways to match the old index but not the one proposed here, so I'd expect the performance difference to be small.

[jeisenbe]

@pnorman - your comments suggest that this change would make a small but positive improvement in the indexes. Do you approve of this change, or are there problems?

[jeisenbe]

Thank you, this change to the indexes should be an improvement.

[pnorman]

Do you approve of this change, or are there problems?

Operational costs of changing indexes

[jeisenbe]

Should it be merged now, for this release, or do you want this delayed until we have another PR that requires updating indexes? For example, we could merge it to the schema-changes branch.

[jeisenbe]

@pnorman - is it ok to merge this PR for the next release, or do we need to wait?

[pnorman]

I'm not sure why we need it, but if we're going to merge it, now is okay

[pnorman]

Let's ship it with the schema changes

[jeisenbe]

Plan is to merge this PR at the same time the schema_changes branch is merged to master - I hope it will be this month.

[pnorman]

I merged this in to schema_changes, so it'll get brought in to master when we merge that.