bdfm1m1aMessages (System Error, Online, Offline) and Master Glossary

P

packing
A TPFDF operation that reduces the number of blocks used to hold logical records (LRECs) contained in a subfile. A pack operation is initiated by the TPFDF product when any LREC has been deleted and the number of LRECs in any block falls below a threshold defined in the DSECT macro or DBDEF macro for the file. The number of LRECs placed in each block is also controlled by the DSECT or DBDEF macro. A pack operation can also be initiated by an application program when the subfile is closed, or by the ZUDFM or ZFCRU commands.

parameter table
The source of parameter values that define how a capture/restore utility, information and statistics environment (CRUISE) function is processed.

parametric recoup
The attribute of the file recoup program that allows the program to be activated and controlled by parameter lists.

parent node
In a B+Tree index, a node that produces and points to a lower-level child node. See also child node and sibling node.

partitioned file
A file where the prime blocks are grouped together into different partitions. Each partition has the same number of subfiles. The prime blocks of the different partitions follow each other sequentially on DASD. For example, if there are three partitions (A, B, C), and each contains four prime blocks, the prime blocks occur in the sequence: A1, A2, A3, A4; B1, B2, B3, B4; C1, C2, C3, C4. You can easily increase the number of partitions by increasing the size of the file. You cannot easily increase the number of prime blocks.

path
A means of referencing a detail file or intermediate index file from an index file. Each different reference is identified by a path number (0, 1, 2, ...) defined by the database administrator. See also update path and read-only path.

pool file
A TPFDF file where the prime block is contained in a TPF or ALCS pool record. Typically, pool files are used for detail files or intermediate index files. Contrast with fixed file.

primary key
Synonym for LREC ID.

prime block
The first block in the chain of blocks that comprise a subfile. All other blocks are referred to as overflow blocks. The subfile can contain zero or more overflow blocks. The prime block is either a fixed file or pool record. See also fixed file, pool file, and overflow block.

pushdown chaining
A file in which records are always added to the prime block of the subfile. If there is not enough room, the logical records (LRECs) in the prime block are moved to a new overflow block, the prime block is initialized, and the LREC added. A pushdown chaining file is indicated by bit 3 of symbol &SW00OP1 in the DSECT of the file.