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Problem Report 0395 Details

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This page provides all information on Problem Report 0395.

Report 0395 Actions

    Problem Report Number 0395
    Submitter's Classification Specification problem
    State Resolved
    Resolution Rejected (REJ)
    Problem Resolution ID REJ.X.0014
    Raised 1993-01-04 08:00
    Updated 2003-03-13 08:00
    Published null
    Product Standard Internationalised System Calls and Libraries (XPG4)
    Certification Program The Open Brand certification program
    Test Suite VSX4 version 4.2.4
    Test Identification dm.isam/ix/isindexinf 5
    Problem Summary PG4R.014 This error brings up the subject of locking semantics. Our ISAM implementation offers users the ability to do locking on a per file descriptor basis (that is: a lock taken through one file descriptor ...
    Problem Text

    This error brings up the subject of locking semantics. Our ISAM
    implementation offers users the ability to do locking on a per file
    descriptor basis (that is: a lock taken through one file descriptor
    conflicts with ANY user of ANY other file descriptor), rather than on
    a per pid basis (that is: a lock taken by one process through ANY file
    descriptor will conflict ONLY with other processes, regardless of what
    file descriptor is being used). This choice is not specified by the
    X/Open ISAM Specification.

    VSX makes use of per pid locking in two ways: It routinely forks a
    process (resulting in a different pid) and expects locks obtained
    through an already open file descriptor to conflict with locks taken
    by a different process through the same file descriptor (i.e. without
    calling isopen again). VSX also expects that if a process has a file
    open in shared mode (i.e. opened without the ISEXCL flag) it will
    be able to open an additional file descriptor in exclusive mode. This
    behavior is not specified by the X/Open ISAM Specification.

    We fixed this problem by closing the shared file descriptor before
    opening an exclusive one. Once the operations requiring exclusive
    access are done, the exclusive file descriptor is closed and the file
    is reopened in shared mode.

    This problem has already been acknowledged by X/Open in the VSX
    questionnaire.

    Test Output

    ************************************************************************
    /tset/dm.isam/ix/isindexinf/T.isindexinf 5 Unresolved

    Test Description:
    correct information returned into the buffer when isfd is a valid file
    descriptor, buffer points to a structure of the type keydesc and
    number parameter is set to a valid key number after some indexes have
    been added and deleted.

    Test Information:
    Deletion reason: external error - isopen() on file isinfo-t.1 in
    EXCLusive mode
    RETURN VALUES: expected: 0, observed: 2
    ERRNO VALUES: expected: 0 (NO ERROR), observed: 1013 (EFLOCKED)
    ISSTAT1 VALUES: expected: 0, observed: 9
    ISSTAT3 VALUES: expected: 0, observed: 9

    ************************************************************************

    Review Information

    Review Type TSMA Review
    Start Date null
    Completed null
    Status Complete
    Review Recommendation No Resolution Given
    Review Response
    On page 17 of the ISAM Developers Specification it states that

    Both automatic and manual locking techniques allow other processes
    to read records locked by the current process as long as the other
    processes are not trying to lock those records (either manually or
    automatically). However, processes cannot lock, re-write or delete
    records locked by another process.

    This description states that locks are related to processes rather than to
    ISAM file descriptors as is suggested by the rationale provided in support
    of this interpretation request. The granting of this interpretation request
    is not recommended.

    Review Type SA Review
    Start Date null
    Completed null
    Status Complete
    Review Resolution Rejected (REJ)
    Review Conclusion
    This interpretation request is refused.

    Problem Reporting System Options:

     

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