Key takeaway
Migration readiness combines reconciliation, application behavior, access, recovery, and an agreed cutover decision. Define rollback before the production switch.
A database migration changes more than where records live. Applications, integrations, reporting, permissions, and support procedures may all depend on the old environment. Start with an inventory of those dependencies and finish with evidence that the new environment supports the work. This checklist is a planning framework, not a production execution script.
Inventory the data and everything that uses it
List tables, views, relationships, constraints, jobs, integrations, connections, and reports. Record application owners and the business periods each report must preserve. Include less visible dependencies such as scheduled exports, administrator tools, and a process that reads a file after a database job completes.
Classify each item as migrate, transform, retire, or retain temporarily. Agree on retention and approved handling with the owners. A migration should not become an unreviewed opportunity to delete records or broaden access. Preserve originals and protected backups until an authorized retirement decision is made.
Make transformations explicit and repeatable
For each changed field, document its source, target type, transformation, default behavior, and exception rule. Dates, decimal precision, identifiers with leading zeros, and empty versus null values need specific cases. An identifier is not necessarily a number simply because it contains digits.
Use an illustrative mapping: Open, Pending Review, and Closed map to three approved statuses. An unexpected fourth value enters an exception report, not automatically Closed. Preserve the source value and mapping version so the team can explain how a target record was produced.
Reconcile meaning as well as volume
Compare row counts, key uniqueness, required fields, relationships, and business totals for agreed data slices. Test a recent period and an older period, not only the grand total. Two errors can offset each other and leave that total unchanged.
Record expected and actual results, discrepancies, and their disposition. A sample invoice total or case count should trace to source records. PostgreSQL's constraint documentation explains mechanisms for enforcing rules; migration still needs business acceptance tests beyond what the database can enforce.
Rehearse the switch and the recovery decision
Define who approves cutover, what prevents it, how ongoing writes will be handled, and when the final delta is captured. Test the application against the target with representative reads and writes in an authorized nonproduction environment. Confirm reporting and downstream jobs use the intended connection.
Specify rollback triggers and a decision window. If users write to the new database after cutover, reverting a connection alone may lose or split those changes. Address how post-cutover writes will be preserved or reconciled. A rollback that ignores that question is not yet workable.
Prove recovery and transfer ownership
A backup file is not a tested restore. PostgreSQL documents distinct backup and recovery approaches; choose a suitable method and verify recovery through an approved rehearsal. Include permissions, application connectivity, and required data in that verification.
After cutover, monitor acceptance indicators and transfer mapping rules, reconciliation evidence, connection ownership, runbooks, and outstanding exceptions. AVIZ DATA can scope Data Cleanup & Migration around these deliverables. Broader transitions belong in a separately defined modernization program.
Project checklist
- Dependency inventory approved
- Field mappings and exception rules versioned
- Counts, keys, relationships, and totals reconciled
- Cutover and post-cutover writes rehearsed
- Restore, rollback, and handoff evidence accepted
References
AI-assisted guide checked against the linked platform documentation. Examples are illustrative and are not client results. Platform capabilities can change; confirm the requirements for your environment.