DataLoader/MX Reference Manual (G06.24+)

DataLoader/MX Components
DataLoader/MX Reference Manual—525872-002
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DataLoader/MX File System
DataLoader/MX process from another process to writes to $RECEIVE. You can
use $RECEIVE as input and output at the same time.
There are many benefits to using $RECEIVE as a normal input or output file when
you use other utilities. For example, import can get its input from a named
DataLoader/MX process that has its output stream set as $RECEIVE. Also you can
process an SQL/MP table in its binary form by using the SQLCI COPY command
to copy the table to or from a named DataLoader/MX process. You can also
receive data from FTP directly into DataLoader/MX without having to put it to a disk
file first. You can do this by having the FTP client use get to move a file to a
named DataLoader/MX process.
When you run DataLoader/MX with $RECEIVE as its output, use the -S parameter
to direct DataLoader/MX to generate statistics that include information about the
buffer pool. Use these statistics to build a loading application and to decide how
many DataLoader/MX processes to use.
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Opening nonexistent processes. DataLoader/MX is often used in an environment
where a number of processes, such as DataLoader/MX and import processes,
communicate with each other. In such an environment, processes being opened
must exist before the processes that open them. To simplify this, the
DataLoader/MX file system delays an open when the process being opened does
not exist yet. If an open returns error 14, the file system delays for one second and
retries the open. It repeats this 60 times for a total of a one minute delay before
reporting an error on the open. You can specify a larger or smaller wait time by
using the WAIT modifier.
•
Opening busy files. DataLoader/MX is used in environments where many
processes are started by the OSS shell, some started waited fashion and some
nowaited. In this environment, the OSS shell can start a process before work
needed from a second process has completed. To avoid potential problems,
DataLoader/MX uses the delaying strategy described under the previous item
whenever an open yields error 12.
•
Speed inhibitors. Some types of files can have attributes that reduce access speed
to files. DataLoader/MX checks for these situations and, if present, reports a
warning message and continues processing (these attributes apply only to
Guardian files):
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Unbuffered output disk files
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Output disk files with the REFRESHEOF attribute
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Output disk files on mirrored disks with the SERIALWRITES attribute
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Output disk files with the VERIFYWRITES attribute
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Output ENSCRIBE files with alternate keys
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Input or output ENSCRIBE files with block sizes less than 4096
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Unblocked interprocess communication