Overview

Database file partitioning provides:

A logical database file can be split into several parts, or partitions, where each partition corresponds to a physical file at the file system level. A logical database file is identified by its schema-defined name and is addressable by its name or number. A file partition is addressable by a DbFile instance number and a unique partition identifier (JadeDbFilePartition class partitionID property), which is a positive Integer64 value in the range 1 through 2^32‑15. This unique identifier remains associated with a partition for its lifetime.

When the setPartitioned method is executed for an instance of the DbFile class representing a new database file, the required partition structures are established when the file is first instantiated. Making an existing database file partitioned requires a reorganization to convert the standard map file to the partitioned structure.

A prerequisite for partitioning a database file is that a single class is mapped to the file.

Partitioning a class enables you to locate instances in different partitions of a database file. A file partition is therefore a part of a database file containing a subset of instances of a single class.

When a database file has been partitioned, the set of partitions associated with a schema-defined map file is referred to as a partition set.

The external file name assigned to a file partition is derived from the schema-defined file name and incorporating the partition number as a qualifier, with the following format.

<map_file_name>_part<partition-number>.dat

For details about replicating partitioned file structures and most meta data on SDS secondary databases, see "SDS and Recovery Considerations when Using Partitioned Database Files", in Chapter 1 of the JADE Synchronized Database Service (SDS) Administration Guide.

The JadeDbFilePartition class provides methods that enable you to freeze or thaw a file partition. When a partition is frozen:

When a partition is thawed: