Overlay / Merge Not Working for oclc_server, p_file_99, etc.

• Article Type: General
• Product: Aleph
• Product Version: 17.01

Description:
We are experiencing difficulties when trying to overlay records imported using the oclc_server. The import works and it matches on the correct record. We receive a message that the record was merged with <sysid>, however nothing is really merging. None of the additional fields in the OCLC record are added to the record in our system. The oclc_server log also records that everything worked as it should, but it isn't.

The same happens with Marcive records,loaded with p_file_99.

The RLIN-loading daemon (ue_03) is OK.

Resolution:
The overlay logic has been switched in programs using the generic_loader programs. This includes the oclc_server and p_file_99 in v17-up -- and in v16 when "new_oclc_server Y" or "new_marcive_loader Y" are set.

Some changes to the table headers have been made to explain this switch:
v17 rep_change #905
v18 rep_change #551
v19 rep_ver #013541

Please note that there is no change to any programs in connection with these rep_changes. The changes are to the table headers only -- in order to retroactively explain the change which has been in place from the beginning in the generic_loader programs.

The updated tab_merge says this:
! Note: when running file-99, file-93, manage-18
! and oclc_server with merge_doc_overlay or
! tab_merge_adv_overlay, the preferred
! record is the record in the incoming load file.
! In order to change direction add preferred_doc_switch
! to tab_preferred; it changes the direction
! and switches between the preferred and
! the non-preferred records.

{You might think that being the "preferred record" would mean that its fields would be taken in preference to those of the other record, but that is not the case (or we would not be seeing this problem). It has to do with the direction of the merge.}

Thus, if you are running one of the above programs and doing overlay, you should have, in tab_preferred, preferred_doc_switch in column 2 of the lines pertaining to this program. Examples:
OCLC preferred_doc_switch
MRCV preferred_doc_switch

*NOTE:* Another way to do this -- which sites have implemented successfully -- is to *not* include preferred_doc_switch in tab_preferred, but rather to update tab_merge_overlay, reversing all the "1"s to "2"s and all the "2"s to "1"s in the lines for OCLC and MRCV. If you have done this, and it is working, just leave the tables as they are.

Our apologies for the confusion resulting from these changes.

See KB 16384-36226 for a general discussion of tab_xxxx_def loader configuration files.