Dataloader/MP Reference Manual

DataLoader/MP Examples
DataLoader/MP Reference Manual—424148-003
6-4
Single Source Parallel Maintenance
4>dbl1 /NOWAIT, NAME $dbl3/ -E=err3 &
-I=$RECEIVE(recform=fb<recsize=200>) -X=c -O=$RECEIVE
...
5>dbl1 /NOWAIT, NAME $dbln/ -E=errn &
-I=$RECEIVE(recform=fb<recsize=200>) -X=c -O=$RECEIVE
Command lines 6 through 9 start the SQLCI processes that read the converted and
blocked records and do a PARTONLY load so that each record goes into its
appropriate partition.
6>SQLCI /NOWAIT/ LOAD $dbl1,=part1,RECIN 215, BLOCKIN 31820,
PARTONLY; EXIT
7>SQLCI /NOWAIT/ LOAD $dbl2,=part2, RECIN 215, BLOCKIN 31820,
PARTONLY; EXIT
8>SQLCI /NOWAIT/ LOAD $dbl3,=part3, RECIN 215, BLOCKIN 31820,
PARTONLY; EXIT
...
9>SQLCI /NOWAIT/ LOAD $dbln,=partn, RECIN 215, BLOCKIN 31820,
PARTONLY; EXIT
Single Source Parallel Maintenance
This highly parallel and self-balancing maintenance scenario is implemented by writing
only three user exits. In this case, the downstream DataLoader/MP processes have
user exits that are able to insert and update records.
Figure 6-2 shows a single input stream. Suppose you are inserting or updating a
database as appropriate—not doing a load, but updating changed data.
Again, you must have one initial DataLoader/MP process for your single data source.
You must figure out the best number of additional DataLoader/MP processes by using
DataLoader/MP’s statistics report.
The steps that DataLoader/MP performs are as follows:
1. The initial DataLoader/MP process reads a block of records from the input stream
and sends it to whichever downstream DataLoader/MP process next requests a
block.
2. DataLoader/MP process 1 reads a block of records from the initial DataLoader/MP
process, does any needed data conversions, and performs an insert or update
operation.
3. At the same time, DataLoader/MP process 2 reads a block of records from the
initial DataLoader/MP process, does any needed data conversions, and performs
an insert or update operation. An optimum number of DataLoader/MP processes
should run in parallel.
Figure 6-2 illustrates this process.