Logical twin forward pointers
An invalid logical twin forward (LTF) message will usually be associated with a message for another segment to which no LTF points.
The segment with the invalid LTF pointer will be called LTWIN2, and the segment to which no LTF points will be called LTWIN3 during the rest of this topic. You should zap the invalid LTF pointer of LTWIN2 to the address of LTWIN3. If there is no associated message for LTWIN3, the LTF pointer of LTWIN2 can be set to binary zeros to indicate that it is the last segment on this twin chain.
If there are multiple errors of this type, use logical twin backward (LTB) pointers, LP pointers, or LCL pointers to determine the correct pairs of segments. If a database has LTB pointers, the LTB pointer of LTWIN3 should point to the associated LTWIN2. If the database has LP pointers, the value of the LP pointer should be the same for LTWIN2 and LTWIN3. If the database has LCL pointers, the LCF, LTF, and LCL pointers form a loop which can be used to verify which LTWIN2 to associate with each LTWIN3.
If none of these pointer types exist and multiple errors are present, you must use knowledge of the application and the database to attempt reconstruction.
Since LTF pointers are not used during the unload process, a reorganization can correct these errors.
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