Original description

Queries that use tailable cursors do not stream results if skip() is applied.

e.g.

db.foo.find().addOption(34).skip(1)

Original description:

A capped collection created by an older version of the server can no longer be 'tracked' by a tailable cursor in 2.6.0; there was no issue with these collections using tailable cursors in v2.4.9. The capped collection being used was probably created pre-v2.2, but I'm not sure and can't find a way to determine. This collection did not have an index on '_id', which was added prior to the v2.6.0. upgrade.

This is not an issue if the capped collection is created with v2.6.0.

Steps to Reproduce:

Using a capped collection created in an older version of the server, e.g. 'test.cap1', attempt to track the inserts to this collection using two mongodb shell sessions.

In the first shell, perform inserts, e.g.,

use test
db.cap1.insert( { 'msg' : 'test' } )

In the second shell, attempt to track new insertions, e.g.,

use test
db.cap1.find().addOption(34) // 2 = tailable, 32 = await_data

When running with 2.6.0, no updates are displayed.

If a new capped collection is created using v2.6.0, and the shell commands above are run, the updates are displayed.