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RELATIONS

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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:

FormatMore

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:

PAGESRELATIONSSEGMENTSINDEXES

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.

Typewritten Software • bear@typewritten.org • Edmonds, WA 98026