The Load utility in DB2 is a series of steps. When you need load utility is the first step you always need to know. The answer is if you want to import data into DB2 tables in bulk, then you need to use Load utility. The series of steps also called different phases of DB2 Load utility execution.
There are sample JCLs those are frequently used in Load and Unload of data from to and pro to DB2. In simple terms, LOAD means importing data, and UNLOAD means exporting the data. This is one of the interview question.
The load utility is a little bit like the supercharged, speed version of the import utility.
It supports the full range of capabilities of the import command, but has many more options to control the speed and efficiency of a given load process.
But with added speed comes a cost. To provide this breakneck capability to load data, the load utility sacrifices several important checks and defers several others.
The de-merits of LOAD utility
The load utility only minimally logs its actions and completely ignores table triggers. It defers the changes to indexes and the checks for referential integrity, potentially masking problems until late in the load process.
One more important point, while working on LOAD utility you may get error like COPY PENDING. There are few resolutions you can read here.
Load utility in DB2 come with some key phrases or parameters. These are good for your interviews and to have command over these also good.
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data buffer |
Enables multiple 4KB buffers to be allocated for dealing with data transfer |
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sort buffer sortheap |
Enables a load-specific sort buffer to be allocated, rather than the default |
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cpu_parallelism |
Controls the number of threads allocated for data preparation, such as reading, parsing, and formatting |
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disk_parallelism |
Controls the number of threads allocated to write out loaded data to the DB2 containers |
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fetch_parallelism |
Controls the capability to spawn multiple threads for fetching source data from a cursor defined from another database |
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indexing mode |
Enables the relevant index updates on target tables to be deferred |
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sourceuserexit |
Enables a program to be called to provide the source data |
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