Migrate Oracle to Oracle
Certified — live-tested pathSame-engine Oracle migrations are how you move between hosts, clouds, or versions — and they still fail in the boring ways: half-copied tables, stale sequences, missing indexes. DBShifts moves the schema and every row, defers constraints for speed, reseeds counters, and proves the result with row counts and checksums.
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How the migration works
Connect
Point DBShifts at your source and target. Credentials stay encrypted; SSH tunnels supported for private databases.
Analyze
Automatic schema introspection produces a migration plan: what converts automatically, what migrates with warnings, what needs human review.
Migrate
Schema is created on the target, data transfers in parallel batches with constraints deferred, indexes rebuilt after load.
Validate
Per-table row counts, type-aware checksums on both sides, FK integrity — plus a fidelity report listing anything lossy.
The character set change is the migration
Most Oracle-to-Oracle moves that are difficult are difficult because the character set changes, typically from a single-byte set like WE8ISO8859P1 to AL32UTF8. That is not a copy — it is a re-encoding, and it expands data. A VARCHAR2(10) declared in bytes holds ten single-byte characters and fewer than ten multi-byte ones, so rows that fit in the source do not fit in the target.
Column lengths therefore have to be checked and often widened, or redeclared in CHAR semantics, before the data moves. Oracle ships a tool for exactly this assessment, and the assessment is the part that must not be skipped: the failure mode is a load that stops partway with a value-too-large error on a table nobody expected.
Plans change across versions even though the SQL does not
The schema is identical and the queries are identical, so the risk is not correctness — it is the optimizer. Statistics are recalculated, optimizer features change between versions, and a plan that was stable for years can flip. A same-engine upgrade that is reported as a performance incident is almost always this.
The defence is to capture plans before the move and carry them, via SQL plan baselines or a plan-stability mechanism, so that the new optimizer has to prove an alternative is better rather than adopting it silently. Doing this afterwards means reconstructing what the old plan was from memory.
Check the edition before assuming a lift
Enterprise Edition features do not exist on Standard Edition, and a move that changes edition can therefore fail on objects rather than on data — partitioned tables, compressed segments, bitmap indexes and parallel query all behave differently or are unavailable.
This catches people moving to a cheaper licence or to a managed cloud offering with a different feature set. Inventory the features actually in use rather than the ones the application documentation mentions, because partitioning in particular tends to have been added by a DBA years earlier and never written down.
Oracle → Oracle conversion notes
Engine-specific rules baked into the conversion and transfer pipeline — verified by live certification of this exact pair.
- NUMBER columns are fetched as exact decimals (38 digits), not lossy floats.
- Identifier case differences (Oracle uppercases unquoted names) are reconciled automatically during transfer.
- Empty string = NULL semantics are accounted for in validation so comparisons stay honest.
Frequently asked questions
Is Oracle to Oracle migration production-ready in DBShifts?
Yes — Oracle to Oracle is a certified pair. It passed DBShifts's live certification suite (schema conversion, data transfer, row counts, type-aware checksums over an edge-case fixture) and is battle-tested in production use.
How does DBShifts verify the Oracle to Oracle migration was correct?
Three layers: per-table row counts on both sides, an order-independent type-aware checksum of row data (canonicalized so engine representation differences don't false-alarm), and FK integrity checks on the target. Rows that fail to insert are quarantined with the exact error — never silently dropped — and can be fixed and retried from the UI.
What happens to Oracle types that Oracle doesn't have?
They convert by deterministic rules with a recorded decision: a native equivalent where one exists, a portable fallback (TEXT/JSON/DECIMAL) where one doesn't. Every lossy conversion appears in the migration plan before you run and in the fidelity report after. You can override any mapping per column.
Can I keep Oracle and Oracle in sync after the initial migration?
Yes. DBShifts supports incremental sync (UPSERT-based delta transfers on a sync key) and, for supported sources, real-time change data capture so the target stays current until you cut over.
Do I need to write any SQL or scripts for Oracle to Oracle?
No. Connect both databases, review the generated migration plan (what's automatic, what migrates with warnings, what needs manual review — typically triggers and stored procedures), and run. Procedural code is transpiled best-effort and queued for human review rather than auto-applied.
What changes in a same-engine Oracle migration?
Structurally nothing changes — types map one-to-one. The risks are operational: half-copied tables, sequences left pointing at 1, and indexes that never got rebuilt. DBShifts reseeds counters to MAX(id)+1, defers then rebuilds constraints and indexes, and proves the copy with row counts and checksums.
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