UDS/SQL databases can be structured with the following page formats (see section "Formatting the compiler database with BCREATE"):
2-Kbyte format with a page length of 2048 bytes
4-Kbyte format with a page length of 4000 bytes
8-Kbyte format with a page length of 8096 bytes
You use the BPGSIZE utility routine to
convert a database to a format with a larger page length (see section "Converting databases with BPGSIZE")
reduce the memory space requirements for realms of a database without changing the page length
remove any FPA extents that may be present for each realm. BPGSIZE combines the entire FPA into a single FPA that consists solely of the FPA base.
combine DBTTs. BPGSIZE combines the DBTT base and DBTT extents to form a new DBTT base.
In order to convert a database and its associated applications, you will need to perform the following individual steps:
check the criteria required to convert the database to a larger format,
convert the database to a larger format by using the BPGSIZE utility routine,
adapt the database schema and subschemas (i.e. restructure the database), and
determine and adapt applications affected by the database conversion if required. Note, however, that converting a database to a larger page format does not always involve the adaptation of application programs that work with the database.
The individual steps required for conversion, i.e. converting the database with BPGSIZE, restructuring it, and adapting application programs, need not be performed at the same time. In other words, normal database operation is possible between these steps.
Two typical conversion examples reflecting different application scenarios are outlined at the end of this chapter, including the case that occurs most frequently in practice.