SQL Update Logging on Active Server | High Availability | Teradata Data Mover - Logging SQL Updates on the Active Server - Teradata Data Mover

Teradata® Data Mover User Guide

Product
Teradata Data Mover
Release Number
16.20
Published
November 2021
Language
English (United States)
Last Update
2021-11-04
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wph1512683331242.ditamap
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B035-4101
lifecycle
previous
Product Category
Analytical Ecosystem

When starting the active synchronization service, dmSyncMaster.json is created in the specified path as the value of sql.log.directory in sync.properties. By default, the service writes the SQL updates file to /var/opt/teradata/datamover/logs/dmSyncMaster.json. Triggers installed on the repository tables regenerate INSERT statements. However, the daemon regenerates the UPDATE and DELETE statements. All the data is written to the DMAuditLog table. From there, the active sync service reads the data and inserts it into the dmSyncMaster.json file. Another process running on the active reads the SQL statements from dmSyncMaster.json and sends the statements to the standby.

When a standby server connects to the active server, the active synchronization service creates slave_clientName.lastread in the path that is specified as the value of sql.log.directory in sync.properties.slave_clientName.lastread tracks all SQL statements sent to the standby server. The service creates a specific .lastread file for each standby server that connects to the active server. For example, if your Data Mover environment has two standby servers, repos_bu1 and repos_bu2, and you run the synchronization service on each standby server, the service writes the following files:

  • /var/opt/teradata/datamover/logs/slave_repos_bu1.lastread
  • /var/opt/teradata/datamover/logs/slave_repos_bu2.lastread