Different Values for Columns TRAILER_CAP_LOC and LEADER_CAP_LOC When There Is Only One Location in Channel

Issue

The HVR catalog table HVR_STIN<Channel Name>_<Target Location> contains different values for columns TRAILER_CAP_LOC and LEADER_CAP_LOC when there is only one location in the channel.

Environment

HVR 5

Resolution

This issue can be resolved by removing the directory which is no longer used by the HVR channel. The change will be seen in HVR_STIN<channel name>_<tgt location> only when the next integrate cycle completes.

Cause

The leader location is the capture location whose changes have arrived most recently. Column leader_cap_loc contains the leader’s location name and column leader_cap_begin contains a time before which all changes captured on the leader are guaranteed to be already integrated. The trailer location is the location whose changes are the oldest. Column trailer_cap_loc contains the trailer's location name and column trailer_cap_begin contains a timestamp.

If the channel contains only one capture location then TRAILER_CAP_LOC and LEADER_CAP_LOC are same. However, if the channel contained a location named 'mra' in the past which was renamed to 'mrc' recently, then the LEADER_CAP_LOC will be 'mrc' and TRAILER_CAP_LOC will be 'mra'.

This happens because the directory $HVR_CONFIG/router/<hub name>/<channel name>/ still contains the directory loc_mra.