In this blog post, let’s learn about the error message “165 ISAM error: TEXT or BYTE column does not exist.” in Hydra and the description of the error.
Error Message
165 ISAM error: TEXT or BYTE column does not exist.
Error Details
This operation has returned an invalid BYTE or TEXT value. Possibly the data pages have been corrupted. Roll back the current transaction. Have the database server administrator use tbcheck -D, oncheck -D, or onutil to get more information about the problem.
If the program is operating with Dirty Read or Committed Read isolation, this code might indicate that another process or thread has deleted the BYTE or TEXT value and its pages have been partly reallocated to an unrelated value. A program using Dirty Read isolation can read rows that have been deleted if the deletion has not yet been committed. If the deletion is committed while the program is reading a BYTE or TEXT value, and if the space allocated to the value is reused for some other program, this error code might be returned.
When a program uses Committed Read isolation, it does not see a row that has been marked for deletion; however, no lock is placed on a row that is not read for update. BYTE or TEXT data is read in a second step, after the row has been fetched. During this lengthy step, it is possible for another program to delete the row and commit the deletion and for the storage space to be reused. To determine if this has occurred, the program should stop processing the BYTE or TEXT value and reread the row. If the program can no longer read the other fields in the row, the row has been deleted. If the program can still read the row, the storage space is corrupted.