ORA-08103 could also mean a corrupted object/table. Run analyze ... validate structure. In case of select * from XXX optimizer is using FULL SCAN which is running into table structure corruption while in case of select * from XXX where (YYY<=0 OR YYY>=0) it could be using index range scan which can be bypassing table structure corruption since data is accessed directly by rowid.

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Did you use INTO clause with ANALYZE? If you did, check for violating rowids in INTO clause table. If you did not check the same in INVALID_ROWS table (assuming you have one - otherwise run UTLVALID.SQL to create it and run analyze again). However, since ANALYZE failed there is a good chance INVALID_ROWS table will be empty. You can also issue:

CREATE TABLE XXX_COPY AS select * from XXX where (YYY<=0 OR YYY>=0);

check if it is not missing any rows, drop and recreate table XXX, populate it with data from XXX_COPY. However, I would go with dbverify first and I would analyze not just datafiles where table XXX data reside but SYSTEM tablespace datafiles too, since it could be data dictionary corruption. Keep in mind, if it is data dictionary corruption, droping table XXX means corrupted space can be reused by some other object in the future and you might have issues again (it is like a ticking bomb), so run dbverify against system tablespace.

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