Valid For
Extract for all databases except Teradata.
Description
Use the UPDATERECORDFORMAT
parameter to cause Extract to combine the before and after images of an UPDATE
operation into a single record in the trail. It is valid for Extract in classic and integrated capture modes; it is valid for a master Extract though is not valid for pump Extract.
Before images are generated when the GETUPDATEBEFORES
, GETBEFORECOLS
, and LOGALLSUPCOLS
parameters are used. (In the case of an update to a primary key, unique index, or user-specified KEYCOLS
key, the before and after images are stored in the same record by default. UPDATERECORDFORMAT
does not apply in these cases.) The NOCOMPRESSUPDATES
parameter is required for non-Oracle databases.
When two records are generated for an update to a single row, it incurs additional disk I/O and processing for both Extract and Replicat. If supplemental logging is enabled on all columns, the unmodified columns may be repeated in both the before and after records. The overall size of the trail is larger, as well. This overhead is reduced by using UPDATERECORDFORMAT
.
When UPDATERECORDFORMAT
is used, Extract writes the before and after images to a single record that contains all of the information needed to process an UPDATE
operation. In addition to improving the read performance of downstream processes, this enables column mapping functions to access the before and after column values at the same point in time, rather than having to cache the before image column values while reading the after values.
UPDATERECORDFORMAT
takes effect for all TABLE
statements in the parameter file.
If you specify both UPDATERECORDFORMAT
and FORMAT RELEASE 11.x
or earlier, then Extract will abend.
Note:
Many-columned tables can cause the trail record to reach its maximum size when UPDATERECORDFORMAT
is used. The rest of the record is continued in one or more additional, chained record fragments. This has a minor effect on processing performance.
Default
UPDATERECORDFORMAT COMPACT
Syntax
UPDATERECORDFORMAT [FULL | COMPACT]
FULL
Generates one trail record that contains the before and after images of an UPDATE
, where the before image includes all of the columns that are available in the transaction record for both the before and after images. When viewed in the Logdump utility, this record appears as GGSUnifiedUpdate
.
COMPACT
Generates one trail record that contains the before and after images of an UPDATE
, where the before image includes all of the columns that are available in the transaction record, but the after image is limited to the primary key columns and the columns that were modified in the UPDATE
. UPDATERECORDFORMAT COMPACT
is recommended for configurations that include an integrated Replicat. This is the default.
When either FULL
or COMPACT
are viewed in the Logdump utility, the record appears as GGSUnifiedUpdate
. The record contains the following:
a header
the length of the before image
the before values of each column
the after values of the primary key, unique index, or KEYCOLS
columns
the after values of the modified columns
internal token data
Example
UPDATERECORDFORMAT COMPACT