The object storage databases are a set of DB2 databases containing
two types of data:
- Descriptive information about objects
- Actual data for the objects stored at the DB2 sublevel of the
OAM storage hierarchy
Each Object storage group has an object storage database.
Each object storage database contains tables for an object directory
and object storage. The object directory table contains descriptive
information about each object. Object storage tables contain the objects.
A separate table space exists for each table. Each database has three
required tables:
- An object directory table (contains descriptive information about
objects)
- A 4 KB table (contains the data for small objects)
- A 32 KB table (contains the data for larger objects up to 256M)
LOB support requires the LOB storage structure in addition to the
three tables mentioned above. The new structure stores object data
that is greater than 32 KB or 32640 bytes for storage groups that
are LOB enabled. The LOB storage structure consists of two tables:
- A LOB base table (resembles the 32 KB table with the addition
of a ROWID column and changing the OTOBJ column datatype from 'long
varchar' to BLOB.
- A LOB auxiliary table (contains the actual BLOB object represented
by the OTOBJ column in the LOB base table).
Note: Reference to the LOB storage structure refers
to both the LOB base table and the LOB auxiliary table.
OAM uses multiple object storage databases, each containing the
three tables mentioned above. Table 1 shows the tables
and table space names.
Table 1. Object
storage database naming conventionsDatabase Name — hlq |
Table
Name |
Table
Space Name |
Contents |
hlq.OSM_OBJ_DIR |
OSMDTS |
Object directory |
hlq.OSM_04
KB_OBJ_TBL |
OSMOTS04 |
Small objects |
hlq.OSM_32
KB_OBJ_TBL |
OSMOTS32 |
Large objects
(LOB support enabled) |
hlq.OSM_LOB_BASE_TBL |
OSMLBTS |
LOB base table |
hlq.OSM_LOB_AUX_TBL |
OTLOBAX1 |
Large objects (LOB support enabled) |
Sample programs that define these databases and tables are shipped
with OAM. You must update these programs to meet the requirements
of your installation before they are run.
The tables defined by the storage administrator will not be used
by OAM unless they are related to an Object storage group through
the services of ISMF. This relationship results in the definition
of the DASD level of the OAM hierarchy for the specified Object storage
group, and the object directory for all levels of the object storage
hierarchy in that storage group. (See Figure 1.)
The object directory table from each three-table set contains an
entry for each object stored in an Object storage group. The object
itself might exist in one of the object storage tables on DASD or
it might exist on optical disk or tape.
Table indexes are necessary for performance. Within an Object storage
group, the directory table has three indexes, and each object storage
table has a single index. All indexes are unique. Indexes are searched
in ascending sequence (ASC).
Note: You must calculate the space required for the indexes
separately because it is not included in the directory and object
field sizes outlined in each table.
For the sample jobs CBRIALC0 and CBRISQL0, see Sample library members.
Figure 1. Object Storage Group Database Structure