DB2 mount command performance factors

What are the constraints on the Performance of DB2 load commands? This is a problem that many people have mentioned. The following describes the performance factors of the DB2 load command for your reference.

When importing data from a file to a table, when the data volume is very large, the DB2 load command obviously shows an advantage, because it is not like the import command to insert a row each time, check whether the constraints are met on each line. Load the command to read data building pages from the input file and write these pages directly to the database, when loading each row of data, the system does not determine whether the constraints are met. In addition, the loading command does not write logs. All these factors cause the loading efficiency to be higher than the import efficiency.

In addition, the DB2 mount command has some options to control performance factors:
1. copy yes/NO and Nonrecoverable
① Nonrecoverable unrecoverable): The specified Mount operation cannot be recovered and cannot be restored by subsequent rollback operations. The rollback operation ignores the transaction and marks the table that is being loaded as "invalid ".

② Copy No default option): In this case, if the archiving log of the database in which the table is located is enabled, the tablespace in which the table is located will be in the backup pending state after the mounting is complete, the tablespace is writable only after the database or tablespace is backed up. The reason is that the changes caused by the loading operation are not recorded, so it is necessary to back up the database or table space to recover the fault after the loading operation is completed.

③ Copy Yes: in this case, if the archive log of the database is enabled, the changes to the load operation will be saved to the tape, directory, or TSM server, and the tablespace will no longer be in the backup pending state.

2. Fastparse
This file type modifier is used to reduce the number of data checks. It can be used only when data is known to be correct, especially for files of the DEL and ASC types.

3. Anyorder
If the SAVECOUNT option is not used, this parameter can be loaded without following the data sequence in the input file. When the CPU_PARALLELISM option is greater than 1 on the SMP symmetric multiprocessor system, this parameter improves the loading performance.

4. Data Buffer
This parameter is used to specify the number of 4 K memory pages allocated from the stack. As the internal buffer for loading, specifying a large buffer helps improve the loading performance.

5. CPU_PARALLELISM
This option can only be used on the SMP system and can indicate how many processes or threads are used to parse, convert, and format data.

6. Disk_Parallelism
This option specifies the number of processes or threads that write data to the disk.

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