Valid for
Extract
Description
Use SOURCEISFILE
or SOURCEISTABLE
to specify whether the source is a file or a table. In many cases, source and target files are synchronized with utilities such as FUP DUP
or SQLCI LOAD
. These utilities establish a point at which subsequent changes made to the source can be applied accurately at the target. However, if mapping is specified between source and target, or if the target is a non-NonStop database, conversion must take place before load.
SOURCEISFILE
reads and processes records from the source file itself rather than the audit trail. If you specified user exits or column maps when Extract processes database changes through the audit trail, also specify SOURCEISFILE
so that the same mapping can be applied before a full-scale file load. Therefore, only one set of mapping routines is required for managing both full synchronization and incremental change activities.
Syntax
SOURCEISFILE | SOURCEISTABLE [, FASTUNLOAD | FASTUNLOADSHARED] [, SQLPREDICATE] [, SELECTVIEW] [, RESTARTCHECKPOINTS]
FASTUNLOAD
Processes the file or table several times faster than the default method. Records are output in random order, rather than primary key order. FASTUNLOAD
has no effect when an SQL view is specified. The FILE
parameter option PARTITIONS
can restrict the data retrieved to a certain subset of the file or table.
FASTUNLOAD
fails if other openers exist for the file or table (the file is opened in protected mode).
FASTUNLOADSHARED
Allows a shared open of the source file or table. Use this only on files that are not receiving updates at the same time data is being extracted.
SQLPREDICATE
Uses any WHERE
clause designated as part of a TABLE
entry as criteria when selecting data from the source table. SQLPREDICATE
can dramatically reduce extraction time when only part of the source table needs to be extracted. This option only works when the source is an SQL table.
You can start separate Extract processes to retrieve data from selected partitions from large tables in parallel. Each process selects a range of data from one or more partitions. When SQLPREDICATE
is specified, only relevant partitions are scanned.
SELECTVIEW
Selects data from a specified SQL view in the FILE
parameter. Without SELECTVIEW
, Extract selects data from the base table of the view, then maps the base table columns to the view columns (this also occurs when processing audit trails and a view is specified).
SELECTVIEW
is required to process multiple table joins and aggregation views. Use SELECTVIEW
to format complex query output for compatibility with other platforms. Rather than using standard utilities that output a record at a time, this method takes advantage of Extract's high performance buffering and cross-platform features.
RESTARTCHECKPOINTS
Instructs Extract to save checkpoint information allowing restart at the last record read if the process stops or abends. See"Using RESTARTCHECKPOINTS" for conditions and restrictions.
Using RESTARTCHECKPOINTS
You can use RESTARTCHECKPOINTS
for:
SQL/MP source tables with or without the SQLPREDICATE
option
Enscribe whether or not you use the FILE
STARTKEY
and ENDKEY
options
Both SQL/MP and Enscribe with or without FASTUNLOAD
.
RESTARTCHECKPOINTS
is valid only for Extracts added from GGSCI
using SOURCEISFILE
or SOURCEISTABLE
.
A positioned restart is valid only if RESTARTCHECKPOINTS
is in the parameter file when the Extract starts initially. The process will start from the beginning of the file if RESTARTCHECKPOINTS
is added or removed for any subsequent restart.
Either SOURCEDEFS
or DICTIONARY
and DEF
are required for Enscribe source files.
You must not make any of the following changes to the parameter file when restarting from a position other than the beginning of the file. If you must make these changes, you must delete and re-add the Extract group.
Removing checkpoint information by:
Removing the current Data File Checkpoint
file from the parameter file. This file can be identified with the INFO EXTRACT
command.
GGSCI> INFO EXTRACT EXTPART Extract EXTPART Last Started 2010-12-06 12:39 Status RUNNING Task type SourceIsFile Process $TSE01 Checkpoint Lag: unknown Data File Checkpoint \NY.$DATA02.ACDATA.ACPART . . .
Removing the current output checkpoint. This is also identified in the INFO EXTRACT
command.
GGSCI> INFO EXTRACT EXTPART . . . Record 30977 Target Extract Trails Rba Max MB \NY.$DATA02.ACDATA.TX000001 2168775 3.
Adding or removing the FASTUNLOAD
option
Adding a new EXTFILE, RMTFILE,
or RMTTASK
Changing the source file or table significantly, such as changing the key columns or their length or datatype
Changing a STARTKEY
or ENDKEY
in a way that alters the file access method.
It is not recommended that you add files or tables to the parameter file after start-up and before a restart. They may not be extracted.
Replicat processes require the HANDLECOLLISIONS
parameter during a restart of a RMTTASK
Extract.