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    Oracle error: io_z34_write; unique constraint (xxx50.z34_ID ) violated

    • Article Type: Q&A
    • Product: Aleph
    • Product Version: 20


    We see these Oracle errors in www_server and pc_server logs:

    Oracle error: io_z34_write
    ORA-00001: unique constraint (xxx50.Z34_ID) violated

    What does this mean?


    The "unique constraint" error indicates that you are trying to write a record with the same key as an already existing record. The z34 is the IP Statistics table. There is only one z34 table per server (that of the pw_library). {The pw_library is specified in aleph_start (setenv pw_library).}

    The system uses the last-z34-sequence number in the util g/2 of the pw_library to decide what key to assign next. When a key of 9999999 is reached, the system starts over with a key of 0000001. Thus, the unique constraint can result from either the z34 being filled up or from the last-z34-sequence being mis-set.

    In the former case, you should run UTIL A 13 ("Drop statistics table") to clean out the z34. (We suggest adding the util /a/13 to the job daemon as a weekly routine.)

    In the latter, you would re-set the last-z34-sequence to a correct value.

    Additional Information

    A Z34 record is generated automatically by the system if the create_statistics flag in $alephe_root/www_server.conf or $alephe_root/pc_server_defaults is set to "Y". The system does not use the z34. If you don't have SQL or other reports running against it, we recommend that you change this to "N" (in which case util a/13/b can be removed from the job_list).

    As described in Article 000034859, the z34 was superceded by the z69 in version 16.02  (When are z34's written? z34 vs. z69 ).We suggest that you:
    1. change the create_statistics flag in ./alephe_root/pc_server_defaults and www_server.conf to "N";
    2. do you util a/17/1 in pwd50 to reinitialize the z34 (and recover the space it is occupying).

    Category: Web OPAC (500)

    • Article last edited: 2/10/2015