RDB/VMS Relational Database Operator ANALYZE — VMS CDD+_4.1A
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 how many pages are filled what each percentage, counted by tens.
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.