Assisted migration service from SQLite to PostgreSQL with validation and rollback

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Reviewing documents and charts during migration planning, validation and rollback Photo: Mikhail Nilov / Pexels

Has your project outgrown SQLite’s limits for concurrency, referential integrity or reporting? Our assisted migration service from SQLite to PostgreSQL plans, executes, and verifies each step to reduce risk. We implement type mapping, controlled data loads, integrity tests and a tested rollback path.

When it makes sense to migrate from SQLite to PostgreSQL

SQLite is excellent for prototypes and embedded apps. As your project grows, limits appear: concurrency, referential integrity and heavy reporting. PostgreSQL provides robust transactions, advanced types and powerful extensions.

Migration brings scalability and safety, provided the path is planned. We cover cutover windows, validations and low-disruption strategies. For scenarios that require a smooth swap, see our zero-downtime database migration strategy (/en/zero-downtime-database-migration-cdc).

  • Concurrent reads and writes
  • Reliable foreign keys and constraints
  • Indexes and complex queries with better performance
  • Mature backup, restore and observability capabilities

What’s included in the service

We cover everything from diagnosis to post-migration, delivering practical, auditable artifacts. The goal is a predictable, tested and reversible transition.

You receive versioned artifacts, automated scripts and clear runbooks to operate and evolve the database after cutover. See our guide on migrations and rollbacks in PostgreSQL (/en/postgresql-migrations-rollbacks).

  • Inventory of tables, volumes and dependencies
  • Target PostgreSQL model: types, indexes and FKs
  • Type mapping and normalization of problematic data
  • Extraction, load and verification scripts (dry-runs included)
  • Cutover plan with Go/No‑Go checklist
  • Data validation by counts, sampling and checksums
  • Tested rollback plan and operational documentation

Critical technical differences and how we handle them

Migration is not just export-and-import. There are differences between SQLite and PostgreSQL that require explicit decisions and targeted tests.

The table below summarizes common points and typical precautions during migration.

Topic Migration considerations
Numeric types Review INTEGER vs BIGINT; adjust DECIMAL scale/precision.
Autoincrement Convert AUTOINCREMENT to SEQUENCES and DEFAULT nextval().
Booleans Normalize 0/1, 'true'/'false' to boolean type.
Dates and timezones Standardize timezones; use timestamptz when appropriate.
Collation and accents Set collation; review ordering and case-insensitive searches.
Foreign keys Create explicit FKs; handle orphaned rows before loading.
Indexes Plan indexes by cardinality and query patterns.
SQL dialect Adjust LIMIT/OFFSET, UPSERT (ON CONFLICT), functions and joins.
Concurrency Review transactions and isolation levels; avoid long-held locks.
Triggers and defaults Reimplement logic in triggers/constraints that are compatible.

Project phases: from discovery to cutover

We structure the work into phases that reduce uncertainty and reveal risks early. Cutover happens only when readiness criteria are met.

After cutover we monitor query behavior and apply quick index and configuration adjustments. See also our PostgreSQL hardening and tuning service (/en/hardening-tuning-postgresql-erp-reports).

  • 1) Discovery and scope: data, traffic, SLAs and possible windows
  • 2) Data audit: nulls, formats, duplicates and orphans
  • 3) Target schema design and review with the team
  • 4) Proof of concept: subset of data and critical queries
  • 5) Extraction and load pipelines with dry-runs and measured timings
  • 6) Validations: counts, samples and divergence queries
  • 7) Full rehearsal and Go/No‑Go checklist
  • 8) Cutover and post-migration monitoring

Data validation: how we confirm things match

Validation starts before cutover and continues afterward. We use multiple complementary techniques to build confidence and detect differences early.

When possible, we compare business query results to ensure reports and KPIs remain consistent after migration.

  • Per-table counts and logical partition counts
  • Checksums by batch and stratified sampling
  • Comparison of aggregates by period and category
  • Divergence queries to find orphans and duplicates
  • Verification of constraints and indexes actually used
  • Application tests pointed at PostgreSQL

Rollback and operational safety during the switch

Rollback needs to be simple and fast. We prepare a clear, tested return path with checkpoints and objective criteria for reverting.

Practices like feature flags reduce the risk of coordinated changes between the app and the database. See ideas in our feature flags guide for PHP monoliths (/en/feature-flags-php-monoliths).

  • Snapshot of the SQLite file before the cutover window
  • Verified PostgreSQL backup after initial load
  • Connection switch and health checks with observation period
  • Go/No‑Go criteria and a documented rollback button
  • Restoration procedure and system re-open steps
  • Post-rollback root cause analysis and corrective plan

Signs you need this service now

Some symptoms indicate that migration is no longer optional and has become a business risk. If you recognize these signs, it’s time to plan the migration.

If the maintenance window is critical, evaluate synchronization strategies and per-module windows depending on your system’s feasibility.

  • Locks and slow reporting on SQLite
  • Intermittent errors under write concurrency peaks
  • Difficulty ensuring integrity across tables
  • Limitations of types, indexes and advanced queries
  • Need for reliable audit, backup and restore
  • Growth plans that require high availability

Frequently asked questions

Is it possible to migrate without downtime?

It depends on the app and its dependencies. SQLite doesn’t natively support CDC. In some cases you can use module-by-module windows, temporary read-only mode or dual-write from the application. In others, a short maintenance window is safer.

Will I need to rewrite my code or ORM?

Usually you swap the driver and adjust migrations and SQL that are database-specific. type differences, UPSERT behavior and functions may require targeted changes. We perform dry-runs and tests pointed at PostgreSQL to detect impacts.

How do you ensure integrity after migration?

We create FKs and constraints in PostgreSQL, validate counts, aggregates and samples, and run divergence queries. We also run application tests. If something doesn’t match, a tested rollback plan is in place.

What can go wrong and how do you mitigate it?

Type mapping, timezones and autoincrement conversions are common sources of error. We anticipate these with audits, POCs and dry-runs using real data. Go/No‑Go criteria and rollback checkpoints prevent prolonged incidents.

What infrastructure resources does PostgreSQL require?

Sizing depends on data volume, access patterns and peak loads. Factors like CPU, RAM, disk IOPS and autovacuum settings matter. We assess the profile and recommend initial sizes and parameters.

Can I recover quickly if I accidentally delete something?

With consistent backups you can restore quickly. In PostgreSQL, techniques like point-in-time recovery help recover objects. See our recovery guide: how to recover a table (/en/recover-dropped-postgresql-table-pitr).

Ready to migrate from SQLite to PostgreSQL safely?

Tell us about your scenario, goals and constraints. We’ll design a migration plan with validation and rollback that fits your delivery pace.

Discuss my migration

See also