A publisher sends a FETCH_OK control message in response to successful fetches. A publisher MAY send Objects in response to a FETCH before the FETCH_OK message is sent, but the FETCH_OK MUST NOT be sent until the End Location is known.
FETCH_OK Message {
Type (i) = 0x18,
Length (16),
Request ID (i),
Group Order (8),
End Of Track (8),
End Location (Location),
Number of Parameters (i),
Subscribe Parameters (..) ...
}
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Request ID: The Request ID of the FETCH this message is replying to Section 8.7.
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Group Order: Indicates the fetch will be delivered in Ascending (0x1) or Descending (0x2) order by group. See Section 6. Values of 0x0 and those larger than 0x2 are a protocol error.
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End Of Track: 1 if all Objects have been published on this Track, and the End Location is the final Object in the Track, 0 if not.
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End Location: The largest object covered by the FETCH response. The End Location is determined as follows:
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If the requested FETCH End Location was beyond the Largest known (possibly final) Object, End Location is {Largest.Group, Largest.Object + 1}
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If End Location.Object in the FETCH request was 0 and the response covers the last Object in the Group, End Location is {Fetch.End Location.Group, 0}
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Otherwise, End Location is Fetch.End Location
If the relay is subscribed to the track, it uses its knowledge of the largest {Group, Object} to set End Location. If if is not subscribed and the requested End Location exceeds its cached data, the relay makes an upstream request to complete the FETCH, and uses the upstream response to set End Location.
If End is smaller than the Start Location in the corresponding FETCH the receiver MUST close the session with
Protocol Violation -
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Subscribe Parameters: The parameters are defined in Section 8.2.1.