RECBYT indexes were introduced in the FairCom DB ISAM API to provide improved space management for variable-length records in a table and to permit backward physical traversal of data files that contain resources and variable length records. A RECBYT index is based on the byte offset (recbyt) of the record being indexed.
RECBYT indexes are optional and the user can disable their creation by specifying the CTCREATE_NORECBYT when the table is created.
When a table is created with RECBYT index support, a RECBYT index is automatically created for the table. The operations on the RECBYT indexes are transparent to the user except for an added performance overhead. c-treeDB API will automatically update the index entries. The RECBYT index will not appear in the list of indexes for a table. The user cannot alter or delete the components of the RECBYT index. The use of RECBYT index has no impact on the fields in the record buffer of a table. There is no field associated with this index.
Note: The RECBYT index enables backward physical traversal of variable-length records. By default, the c-treeDB API API creates this index on every table. Because it is an extra index, it slows inserts, updates, and deletes. Unless you need to walk variable-length records backwards, disable the creation of the index by adding NORECBYT to the table create mode.