What is the use of Rgzpfm?
The Reorganize Physical File Member (RGZPFM) command removes deleted records from (compresses) one member of a physical file in the database, and it optionally reorganizes that member.
How do I reorg files in AS400?
Reorganize physical file in AS400 – RGZPFM
- If we want to arrange the records based on some other key value then we can give the logical file name containing that key value.
- After reorganizing, the records in ACCOUNT get arranged as per the key value of ACCOUNT.
What is reorg in AS400?
The reorg job is moving rows (deleting and inserting rows). This is being done to get all the deleted records at the bottom of the file.
What is access path in as400?
Access path describes the order in which records are to be read. · Access paths can be kept on the system permanently (such as physical or logical file) or temporarily. · OPNQRYF command may create a temporary access path for use one time, and then discard the access path.
What does DB2 Reorg do?
The DB2 reorg command reorganizes the table and its indexes by rebuilding the index data into unfragmented and contiguous area on the disk. This operating requires locking the data for movement. If there are applications that access this data, then the application performance might be degraded.
What is access path?
An access path describes how records in a database file are retrieved. You can define the access path for a database file in various ways. Records in a physical or logical file can be retrieved through an arrival sequence access path or a keyed sequence access path.
What is the use of Ovrdbf in as400?
The Override with Database File (OVRDBF) command is used to (1) override (replace) the file named in the program, (2) override certain parameters of a file that are used by the program, or (3) override the file named in the program and override certain parameters of the file being processed.
What is Reorg and Runstats?
runstats is for collecting indexes and tables statistics information which to enable the DB2 optimizer to generate efficient access plan. reorgs is for reorganizing tables and indexes.
What are the types of access path?
Access paths can be kept on the system permanently (such as physical or logical file) or temporarily. OPNQRYF command may create a temporary access path for use one time, and then discard the access path. ü Sequentially, where each record is taken from the next sequential physical position in the file.
Which of the following provides an access path?
An access path is provided by File key. An access path specifies the path chosen by a database management system to retrieve the requested tuples from a relation.
Is Ovrdbf required before Opnqryf?
When a file is processed with the FORMAT parameter, you must ensure: The OVRDBF command, used with the TOFILE parameter, describes the first file on the FILE parameter of the OPNQRYF command. The FORMAT parameter identifies the file that contains the format used to create the program.
Why is Ovrdbf used?
OVRDBF (Override with Database File) Command in CL. This command is used to override the attribute of a physical file. By using this command we can make our program to use some other file for the one actually named to be used in the program.
Why do we do reorg?
To keep it simple: REORG is a database operation that is executed in DB2 to reorganize the table spaces or index spaces. The purpose of the reorganization is data clustering. This operation reconstructs the data in the table spaces or index spaces, so that the data is unfragmented and physically continuous.
What is Reorgchk?
Reorgchk is a DB2 utility that calculates a number of formulas to determine what kinds of reorgs are needed on what tables. You can run reorgchk on a single table, on a schema, or on all tables in a database. While you can optionally have reorgchk update statistics, I do not recommend it.
What is Runstats?
RUNSTATS is a DB2 utility that scans a table space or indexes to gather information about space utilization and index efficiency. The information gathered is stored in the DB2 system tables and used by the SQL optimizer to select the best access paths during the bind process.
What is a data access path?
What is open data path?
An open data path is the path through which all input and output operations for a file are performed. Usually a separate open data path is defined each time a file is opened.
How many records per minute does rgzpfm store?
The rule of thumb is 10,000 records per minute (worst case). If you want more control of the various steps in RGZPFM, then you could perform the steps manually. Ensure you have a valid copy of the physical file from a regular save.
What does rgzpfm ignore when reorganizing a file?
The RGZPFM command ignores all file overrides that are currently in effect for the job. The file names specified on the FILE and KEYFILE parameters identify the files actually used in the reorganize operation, regardless of overrides that may exist for these files.
How does rgzpfm work on DASD?
If your system does not have twice the size of the original file available, the operating system will perform a rolling compression. If the RGZPFM command uses the KEYFILE parameter, the run time will be dependent on how the records currently reside on DASD. The system will use an existing access path to read the data in the desired order.
What happens if rbdaccpth (*Yes) is specified in a rgzpfm?
If RBDACCPTH (*YES) or RBDACCPTH (*OPTIMIZE) is specified, any access paths that were marked invalid at the start of the RGZPFM will be rebuilt from scratch. Question 7: If a RGZPFM with KEYFILE (*RPLDLTRCD) and LOCK (*EXCLRD) is run, how does this impact someone reading the file using an ODBC SQL select statement?