RDB/VMS Relational Database Operator ANALYZE — VMS RDB_4.1_M
The RDO ANALYZE statement is available for single-file databases
only. Use the RMU/ANALYZE command for multifile databases.
Displays statistics on how the database is using space. ANALYZE
works on the database most recently invoked, and uses a read/write
transaction.
You can display statistics on pages, relations, indexes, or segments.
Example:
RDO> ANALYZE RELATION EMPLOYEES
Additional information available:
Format
ANALYZE ─┬──>
P
A
G
E
S ──────────────────────────┬─> ├──>
R
E
L
A
T
I
O
N
S ─┬───────────────────┬─┤ │ └─> relation-name ──┘ │ ├┬─>
I
N
D
E
X
E
S ──┬┬───────────────────┬─┤ │└─>
I
N
D
I
C
E
S ──┘└─> index-name ─────┘ │ └──>
S
E
G
M
E
N
T
S ────────────────────────┘
Additional information available:
PAGES
Rdb/VMS displays a bar chart showing page usage for the database. This chart indicates how many pages the database uses and the percentage to which each page is filled.
RELATIONS
Rdb/VMS displays a chart with the following information for each
relation defined for the database:
o Total number of records
o Total number of bytes
o Average number of bytes occupied by each record
o Percentage of records that are fragmented (split over more than
one database page)
o Percentage of total space available for a relation used to store
users' data
o Percentage of total space in a relation used to store users' data
SEGMENTS
Rdb/VMS displays a chart with the following information about the
segmented strings stored in the database:
o Total number of segmented string records
o Total number of bytes occupied by segmented strings
o Average number of bytes occupied by each segmented string record
o Percentage of segmented string records that are fragmented (split
over more than one database page)
o Percentage of total space available for a relation that is used
to store users' data
o Percentage of total space in a relation used to store users' data
INDEXES
If you use the INDEXES or INDICES option, Rdb/VMS displays a chart
with five columns that consists of:
o The number of levels in the B-tree needed to store all the index
nodes.
o The total number of B-tree nodes in the index.
o The length (number of bytes) used for the index.
o The number of duplicate values in the index. This value is
always zero in an index defined with the DUPLICATES ARE NOT
ALLOWED clause.
o Any duplicate length used.
More
You must have the Rdb/VMS ADMINISTRATOR privilege to use the ANALYZE statement.