ORA-01555: snapshot too old on LOB objects

ORA-01555: snapshot too old: rollback segment number with name “” too small

Error

ORA-01555: snapshot too old: rollback segment number with name "" too small
ORA-22924: snapshot too old


Cause:
LOB data doesn’t use the Undo segment for retaining the read consistent images.
The old versions are stored in the LOB Segments itself.
ORA-01555 generated as LOB may be corrupted or read consistent image is not available in LOB Segments.
It’s managed by PCTVERSION and RETENTION attributes set for LOB Segment.

Solution:
1. Check corruption in LOB Segments.

For check the corruption follow the following link:

Check and Recover Corruption in LOB Segments

Note: If you don’t find corruption, then go to step 2.

2. Read Consistent image is not available in LOB.

Oracle maintain undo for LOB in itself segments. For checking the parameters follow the following link:

Set parameter for Maintain Read consistent in LOB Segments