12 Storage Management with DB2 for OS/390
3.2.1 TABLE
All data managed byDB2 is associated to a table. The data within the tableis
organizedin columns and rows, and this represents the minimum unit of data that
can be identifiedby the user.
The table is the main object used by DB2 applications. The SQL DML used by
application programs and end users directly referencesdata in tables.
3.2.2 TABLESPACE
A table spaceis used to store one or more tables. A table space is physically
implementedwith one or more data sets. Table spaces are VSAM linear data sets
(LDS). Because tablespaces can be larger than the largest possible VSAM data
set, a DB2 table space may require more than one VSAM data set.
One of three differenttypes of table spaces may be chosen for a specific table:
1. Simple (normally containing one table)
2. Segmented (containing one or more tables)
3. Partitioned (containing one,often large, table)
4. LOB (large object, new type of table space introducedwith DB 2 V6).
The maximum sizeof simple and segmented table spaces is 64 GB,
corresponding to the concatenation of up to 32 data sets, each of up to 2 GB in
size.
A single LOB column canbe 2 GB, and the collection of all LOB values for a
given LOB columncan be up to 4000 TB.
Table1 on page 12 summarizes the partition and partitioned table space sizes for
differentversions of DB2.
Table1. Summary of Partition and Partitioned Table Space Sizes
Up to DB2 V4the total maximum size of a partitioned table space is 64 GB.
Starting with DB2 V5, with the introduction of the LARGE parameter at creation
time, partitioned table spaces mayhave a total size of 1,016 GB, corresponding
to up to 254par titionseach with a data set size of 4 GB.
DB2Version Numberof Partitions MaximumSize Total Maximum Size
V4* 1to16 4GB 64GB
17to 32 2GB 64GB
33to 64 1GB 64GB
V5** 254 4GB 1,016 GB
V6*** 254 64GB 16,256GB
Note: *For a maximum total of 64 GB
Note: **Requires LARGE parameter in CREATE TABLESPACE
Note: ***Requires DFSMS/MVS 1.5 and SMS-managed table space