CMIS Migration to PostgreSQL 15 [RND-996]
Since CMIS 5.12 PostgreSQL DB is supported (cp. [RND-996]).
Migration Strategy for CMIS Server
Only the CMIS Sync functionality, specifically the CMIS Changelog, needs migration.
Changelog Overview:
-
Most of the Changelog is calculated during runtime from the STORAGE_ELEMENT table.
-
Deleted files are tracked in a separate table CMIS_CHANGE_LOG created by the CMIS Server.
-
The complete Changelog merges data from both tables.
Migration Approach:
To simplify the process and avoid migrating the entire CMIS_CHANGE_LOG table, we’ll create a new empty table CMIS_CHANGE_LOG on PostgreSQL.
This requires ensuring all files are synced by the CMIS Client before migration and no further deletions occur on the old OMN system.
In short: All the Deletion-Events from CMIS_CHANGE_LOG need to be processed by all CMIS Sync Clients. Only then we can start fresh with an empty CMIS_CHANGE_LOG table on new PostgreSQL system.
Detailed Migration Steps:
-
Verify all files are synced on CMIS Client side.
Migrate OMN to PostgreSQL:
-
Start OMN once on PostgreSQL to create the schema.
-
Crucial: Do not start the CMIS Server on PostgreSQL yet.
-
If accidentally started, exclude the following tables in data-migration-tool-config.xml:
-
cmis_change_log
-
cmis_databasechangelog
-
cmis_databasechangeloglock
-
-
Run DB migration by using the Data Migration Tool