The RDB$INDICES system table contains information about indexes
    in the database. The following table provides information on the
    columns of the RDB$INDICES system table.

                                Data
    Column Name                 Type      Summary Description

    RDB$INDEX_NAME              char(31)  A unique index name.
    RDB$RELATION_NAME           char(31)  The name of the table in
                                          which the index is used.
    RDB$UNIQUE_FLAG             integer   A value that indicates
                                          whether duplicate values
                                          are allowed in indexes, as
                                          follows:

                                          o  0

                                             If duplicate values are
                                             allowed.

                                          o  1

                                             If no duplicate values
                                             are allowed.

    RDB$ROOT_DBK                char(8)   A pointer to the base of
                                          the index.
    RDB$INDEX_ID                integer   The identifier of the
                                          index.
    RDB$FLAGS                   integer   Flags.
    RDB$SEGMENT_COUNT           integer   The number of segments in
                                          the key.
    RDB$DESCRIPTION             list      A user-supplied description
                                of byte   of this index.
                                varying
    RDB$EXTENSION_PARAMETERS    list      Stores NODE SIZE value,
                                of byte   PERCENT FILL value,
                                varying   compression algorithm, and
                                          compression run length for
                                          this index. Also reserved
                                          for other future use.
    RDB$CARDINALITY             bigint    The number of unique
                                          entries for a non-unique
                                          index. For a unique index,
                                          the number is 0.
    RDB$SECURITY_CLASS          char(20)  Reserved for future use.
    RDB$CREATED                 date vms  Set when the index is
                                          created.
    RDB$LAST_ALTERED            date vms  Set when SQL ALTER INDEX
                                          statement is used.
    RDB$INDEX_CREATOR           char(31)  Creator of this index.
    RDB$KEY_CLUSTER_FACTOR      bigint(7) Sorted Index: The ratio
                                          of the number of clump
                                          changes that occur when
                                          you traverse level-
                                          1 index nodes and the
                                          duplicate node chains
                                          to the number of keys in
                                          the index. This statistic
                                          is based on entire index
                                          traversal. This means last
                                          duplicate node of current
                                          key is compared with first
                                          duplicate node of next key
                                          for clump change.

                                          Hash Index: The average
                                          number of clump changes
                                          that occur when you go
                                          from system record to hash
                                          bucket to overflow hash
                                          bucket (if fragmented), and
                                          traverse the duplicate node
                                          chain for each key. This
                                          statistic is based on per
                                          key traversal.
    RDB$DATA_CLUSTER_FACTOR     bigint(7) Sorted Index: The ratio of
                                          the number of clump changes
                                          that occur between adjacent
                                          dbkeys in duplicate chains
                                          of all keys to the number
                                          of keys in the index. For
                                          unique index, the dbkeys of
                                          adjacent keys are compared
                                          for clump change. This
                                          statistic is based on
                                          entire index traversal.
                                          This means last dbkey of
                                          current key is compared
                                          with first dbkey of next
                                          key for clump change.

                                          Hashed Index: The average
                                          number of clump changes
                                          that occur between adjacent
                                          dbkeys in a duplicate chain
                                          for each key. For a unique
                                          index, this value will be
                                          always 1. This statistic is
                                          based on per key traversal.
    RDB$INDEX_DEPTH             integer   Sorted Index: The depth of
                                          the B-tree.

                                          Hashed Index: This column
                                          is not used for hashed
                                          indices and is left as 0.