System Variable: Transaction Commit Sequence Number - Connect_CDC - connect_cdc_mimix_share - 5 - 5.8

Connect CDC Advanced User Guide

Product type
Software
Portfolio
Integrate
Product family
Connect
Product
Connect > Connect CDC (MIMIX Share)
Version
5.8
Language
English
Product name
Connect CDC
Title
Connect CDC Advanced User Guide
Copyright
2023
First publish date
2003
ft:lastEdition
2023-09-27
ft:lastPublication
2023-09-27T18:12:55.651884

Variable

What you see in omnient.ini

Replacement value

Recommended Target Column Type

Transaction Commit Sequence Number

sv_trans_commit_seqno

16-digit, unique identifier of the transaction that involved the row containing this source column

VARCHAR2(20)

For Oracle, the Transaction Commit Sequence Number identifies when a transaction has been committed. This allows downstream systems to know which rows to apply for a given transaction. In the past, sv_trans_id was used in Oracle to start the SCN of a transaction.

This caused the following issue:
  • Transaction 1 begins
  • Transaction 2 begins and has a higher start SCN than transaction 1
  • Transaction 2 commits
  • Transaction 1 commits and overrides changes that transaction 2 made
  • since sv_trans_id reflects the start SCN, so Connect applies transaction 2 even though the current state of the source database reflects the data changed by transaction 1

Therefore transaction 2 commit is not properly captured (applied) downstream. The use of sv_trans_commit_seqno along with sv_trans_id will help downstream system determine when to properly apply transaction.