ADD EXTTRAIL
Use ADD EXTTRAIL to create a trail for online processing
on the local system and:
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Associate it with an Extract group.
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Assign a maximum file size.
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When attempting to create multiple trail files using
ADD EXTTRAIL, from a single Extract process, the operation will fail if the number of trail files exceed a certain limit. Specifically, when more than 12 trails are created, the following error may occur:2025-11-05T21:16:04Z INFO OGG-08100 Exceeded checkpoint record size (32,768/32,767) in checkpoint file /path/to/checkpoint/file.cpe.This error occurs due to the checkpoint file exceeding the size limit of 32,767 records. The checkpoint file contains CSN (Commit Sequence Number), XID (Transaction ID), and record numbers, which contribute to the file's size.
To avoid this error it is recommended not to create multiple trail files from a single Extract, particularly for performance reasons. The preferred approach is to have a single Extract capture all required data and use the Distribution Service to distribute it to different destinations.
Another alternative option is to run multiple Extract processes if there is a need to reduce the trail file size for each individual destination.
See EXTTRAIL in the Parameters and Functions Reference
for Oracle GoldenGate
Syntax
ADD EXTTRAIL trail_name, EXTRACT group_name
[, MEGABYTES n]
[SEQNO n]-
trail_name -
A two character trail name. It is recommended that both the characters be alphabets, but the first character must not be a number. Oracle GoldenGate appends this name with a nine-digit sequence number whenever a new file is created.
The trail name can also be prefixed with a directory. For example, a trail named
north/eawould have trail files namedea000000000,ea000000001in the$OGG_DATA_HOME/northsubdirectory. -
group_name -
The name of the Extract group to which the trail is bound. A trail can only be assigned to one Extract. Multiple Extracts cannot write to the same trail. However, one Extract can write to multiple distinct trails if needed, but this is not normally required.
-
MEGABYTESn -
The maximum size, in megabytes, of each trail file in the sequence. The default is 500MB and the maximum value is 2000MB.
-
SEQNOn -
Specifies that the first file in the trail will start with the specified trail sequence number. Do not include any zero padding. For example, to start at sequence 3 of a trail named
tr, specifySEQNO 3. The actual file would be named/ea000000003. This option can be used during troubleshooting when a Replicat needs to be repositioned to a certain trail sequence number. It eliminates the need to alter the Replicat to read the required sequence number. The default value is 1.
Limitations
When creating an Extract
trail with the same name as a prior Extract trail, make sure that all trails in that
directory with the same trail_name have been deleted.
When capturing from a MySQL database enabled for group replication, only one trail is allowed for an Extract.