ORA-31004: Length string of the BLOB in XDB$H_INDEX is below the minimum string
Cause: In the XDB$H_INDEX table, the CHILDREN column, a BLOB, must have a certain minimum length without being chained. The calculated length of the LOB was less than the stated minimum
Action: Set the value of the init.ora parameter db_block_size to at least 2K. For XDB to run at its fastest, set db_block_size to 8K
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