1.34 COMPRESSUPDATES | NOCOMPRESSUPDATES
Valid For
Extract
Description
Use the COMPRESSUPDATES
and NOCOMPRESSUPDATES
parameters for Extract to control the way columns are written to the trail record for UPDATE
operations.
COMPRESSUPDATES
and NOCOMPRESSUPDATES
apply globally for all TABLE
statements in a parameter file or they
can be used as on-off switches for individual TABLE
statements.
GETUPDATEBEFORES
is used to decide whether to
get before images or not, and COMPRESSUPDATES
decides if you want
all columns or selected columns. By default, only the after images of update
operations are written to the trail, but by using NOCOMPRESSUPDATES
along with GETUPDATEBEFORES
writes the before image changes as
well, which can be used when implementing Conflict Detection and Resolution
rules.
These parameters support the following databases:
-
DB2 LUW
-
DB2 z/OS
-
DB2 for i
-
MySQL
-
SQL Server
-
PostgreSQL
For Oracle, refer to the LOGALLSUPCOLS
parameter.
Default
COMPRESSUPDATES
Syntax
COMPRESSUPDATES | NOCOMPRESSUPDATES
-
COMPRESSUPDATES
-
Causes Extract to write only the primary key and the changed columns of a row to the trail for update operations, and is the default value. This provides enough information to update the correct target record (unless conflict resolution is required), while restricting the amount of data that must be processed.
Additionally, if a substitute key is defined with the
KEYCOLS
option of theTABLE
parameter, those columns are written to the trail, whether or not a primary or unique key is defined. See "KEYCOLS (columns)" for more information. -
NOCOMPRESSUPDATES
-
Sends all of the columns to the trail. This becomes the default when a table definition does not include a primary key or unique index.
NOCOMPRESSUPDATES
also is required when using the Conflict Detection and Resolution (CDR) feature. See Administering Oracle GoldenGate for more information about CDR.For PostgreSQL, when using
NOCOMPRESSUPDATES
, LOB column data will only be written in the after image of the record if the column was modified.
Parent topic: Oracle GoldenGate Parameters