SAP Sybase IQ implicitly rebuilds CHAR,VARCHAR, BINARY, and VARBINARY columns wider than 255 characters, as well as all LONG VARCHAR and LONG BINARY columns in databases migrated to SAP Sybase IQ 16.0 SP03 the first time a pre-16.0 non-RLV base table is opened for read-write access.
You can also explicitly rebuild wide columns using the sp_iqrebuildindexwide procedure. sp_iqrebuildindexwide can rebuild wide tables by table_name, table_owner, and level. Depending on the argument, this procedure can rebuild all pre-16.0 columns wider than 255 bytes, some or all tokenized FPs, VARCHAR/VARBINARY columns, and all fixed Flat FPs for specified tables in the database.
See sp_iqrebuildindexwide Procedure in Reference: Building Blocks, Tables, and Procedures.