Alibaba Cloud agency cashback Alibaba Cloud DTS Data Sync Interrupted: Primary Key Conflict Resolution

If your DTS data sync task stops with a primary key conflict, the real question is usually not "what is a primary key?" It is: what should I do right now so the sync can continue without losing data or triggering another rollback? In practice, this issue appears when DTS tries to write a row into the target table, but that row already exists with the same primary key, or the target schema and source data are not aligned well enough for incremental changes to land cleanly.

The fastest fix depends on one thing: whether the conflicting row is the correct business record and whether the target database is allowed to be changed. If the answer is unclear, do not restart the task repeatedly. That usually wastes time and can make later troubleshooting harder.

What to check first when the task is interrupted

Before touching the task settings, confirm these points in order:

• Which table stopped: a single table or the whole task.
• Whether the conflict happened during initial full sync or during incremental sync.
• Whether the target already had data before DTS started.
• Whether the source table has a stable primary key and the target table uses the same key logic.
• Whether someone manually edited the target table during sync.

In many real cases, the root cause is not the sync tool itself. It is that the target table already contains the row, or the source application has produced duplicate values that should never have existed in a primary key column.

The three practical ways to resolve a primary key conflict

1. Remove or update the conflicting row in the target

This is the cleanest option when the target row is wrong or outdated. Typical cases include:

• The target table was preloaded with test data.
• Someone inserted a manual correction record into production.
• Alibaba Cloud agency cashback The target already contains a record with the same primary key but an older or incorrect state.

What to do:

• Alibaba Cloud agency cashback Identify the exact conflicting primary key from the DTS task log.
• Check whether the target row should be deleted, updated, or archived.
• Alibaba Cloud agency cashback Make the correction in the target database.
• Resume the task and verify that DTS continues from the interrupted point.

This option is usually safest when the target is supposed to mirror the source and the conflicting record was introduced by mistake.

Alibaba Cloud agency cashback 2. Keep the target row and skip the source change

Sometimes the target row is the business-approved version, and overwriting it would create a larger problem than leaving the sync interrupted. This comes up in reporting systems, temporary migration stages, and some hybrid architectures where the target is not a strict replica.

Use this path only if the business owner accepts that the source row will not be fully synchronized. If the task is mission-critical, skipping a conflict without a written decision is risky. It can create silent data drift that surfaces weeks later in finance, order, or inventory reconciliation.

3. Rebuild the target table and restart the sync

This is the most expensive option, but sometimes it is the least risky. Use it when:

• The target table was built with the wrong schema.
• Many rows are already inconsistent.
• You cannot reliably determine which side has the correct value.
• The conflict is just one symptom of a broader migration error.

If you choose this route, back up the target first, then recreate the table, run a fresh full sync, and only then re-enable incremental sync. In practice, this often costs more time than fixing a single row, but it can save a broken migration from dragging on for days.

Why primary key conflicts happen so often

In the field, the same few causes appear again and again:

• Target pre-existing data: the target table already had records before DTS started.
• Manual intervention: operators inserted or modified rows during synchronization.
• Schema mismatch: source and target tables do not enforce the same key rules.
• Application bug: the source system wrote duplicate business identifiers.
• Wrong sync mode: full sync and incremental sync were not planned together, so old records collided with new ones.

One of the most common mistakes is treating DTS as if it can "merge" inconsistent data automatically. It cannot guess which record is correct. If the target has a conflicting primary key, someone still needs to decide which side wins.

How to investigate without making the situation worse

Alibaba Cloud agency cashback When the task is already interrupted, the priority is to preserve evidence before changing data. A practical workflow is:

1. Open the DTS task details and record the table name, key value, and timestamp of the error.
2. Query both source and target for the same primary key.
3. Check whether the data differs only in non-key columns or whether the row should not exist at all.
4. Review recent application writes, imports, or batch jobs that may have touched the table.
5. Decide whether the fix belongs in the target, the source, or the application logic that produced the row.

If the table is large, do not scan the whole dataset manually. Focus on the specific key value from the error log and work outward from there.

Purchasing Alibaba Cloud DTS before you can even fix the task

Many users only discover the operational side of this problem after they already need a sync task running in production. If you have not purchased DTS yet, the buying process itself can become a blocker, especially if your account is new or your billing profile is incomplete.

What usually matters in real usage:

• Whether your Alibaba Cloud account is fully verified.
• Whether the billing profile matches the legal entity that will use the service.
• Whether the region you picked supports the source and target databases you need.
• Whether your payment method is accepted for the purchase type you want.

If you are buying DTS for a production migration or a long-running sync, choose the account setup carefully. A cheap personal account that later fails compliance review is more expensive than a correctly prepared enterprise account from the start.

KYC and identity verification: where many purchases get stuck

For international cloud accounts, KYC problems often show up in one of three places: registration, activation, or higher-value renewals. Common failure points include:

• Company name mismatch between the account profile and the submitted documents.
• Unsupported ID type or incomplete business registration documents.
• Payment card country, billing address, or legal entity information that does not align.
• Repeated sign-up or billing attempts that trigger manual risk review.

Alibaba Cloud agency cashback For smooth DTS provisioning, make sure the account is approved before the migration window. If the account is still under review when the task needs to start, you may lose the maintenance window and be forced to reschedule the cutover.

Payment methods and what they mean in practice

Payment choice affects more than checkout convenience. It also affects approval speed, renewal stability, and how often your account gets flagged for review.

If you need DTS quickly, card payment is usually the fastest route. If your company needs formal invoices and internal approval, it is better to accept a slower setup than to start with a card and later struggle with compliance or reimbursement issues.

Risk control and compliance reviews: why they happen

Cloud vendors often review new accounts or unusual purchase patterns. This is not unique to Alibaba Cloud. In practice, the most common triggers are:

• New account plus immediate purchase of a higher-risk product category.
• Mismatch between sign-up region, payment method, and usage region.
• Repeated failed payment attempts.
• Large renewals after a long period of inactivity.
• Business information that cannot be matched to public records or submitted documents.

For DTS specifically, the risk is not just account suspension. A delayed review can leave a migration task half-prepared and force you to keep source systems in a change-freeze state longer than planned. If your cutover is time-sensitive, submit documents early and keep the billing information clean from the start.

Usage restrictions that matter during a sync project

Some users buy the account successfully but then run into practical restrictions when setting up DTS:

• Region limits: the source and target may need specific region pairings.
• Resource limits: the account may not have enough quota or permission for the required instance size.
• Database permissions: DTS needs the right account privileges on source and target.
• Network restrictions: firewall rules or security groups can prevent stable replication.

These restrictions often look like "the sync tool is broken," but the actual problem is permissions, quota, or network access. For a production task, verify these before scheduling the first sync run.

Cost comparison: fixing the conflict vs restarting the migration

From a cost perspective, there are three different expenses to think about:

• Cloud service cost: DTS instance charges, data transfer, and related database resources.
• Operational cost: engineer time spent tracing the bad row and validating the fix.
• Business cost: downtime risk, delayed cutover, and reconciliation work after the sync resumes.

In many small incidents, deleting or correcting one conflicting row is cheaper than rebuilding the sync task. But if the same conflict keeps recurring, the cheapest option is usually to fix the source system or redesign the target schema, not to keep repairing the symptom.

A practical rule I use: if the issue is isolated to one row and the data ownership is clear, fix the row. If the same pattern appears across multiple tables, stop and redesign the migration plan.

Real-world situations that change the best answer

Scenario 1: Preloaded target table

A team copied production data into the target for testing, then later reused that target for live DTS sync. The first conflict was immediate and predictable. The right move was not to "force continue," but to clear the target and restart with a clean schema.

Scenario 2: Finance table with manual corrections

Operations staff had manually adjusted a few records in the target database to keep reporting online. DTS then hit a primary key conflict on one of those rows. In this case, the target record was actually the business-approved version, so the conflict had to be resolved by skipping the source row and documenting the exception.

Scenario 3: Duplicate business IDs in source

The source application generated duplicate order IDs during a batch import. DTS was only the messenger. The sync would have failed again even if the target row had been deleted. The real fix was to repair the import logic and then backfill the corrected rows.

FAQ

Will restarting the DTS task automatically fix the conflict?

No. If the conflicting data is still there, the task will usually fail again. Restarting without fixing the row only repeats the same error.

Can I ignore the conflicting row and continue with the rest?

Alibaba Cloud agency cashback Only if the business accepts data drift. In most production cases, you should not skip a conflict unless the data owner signs off on it.

Does a primary key conflict mean my source data is corrupt?

Not always. The conflict may be caused by the target table, a manual edit, or a schema mismatch. Check both sides before blaming the source.

Is it better to use a new target database instead of fixing the old one?

If the target already contains many inconsistent rows, yes. If the issue is isolated to one record, a full rebuild is usually too expensive.

Why did my Alibaba Cloud account get flagged during DTS purchase?

New accounts, mismatched billing details, repeated payment failures, and unusual purchase patterns often trigger review. Prepare KYC documents and keep billing information consistent.

Which payment method is easiest for first-time users?

Card payment is usually the fastest for activation, but enterprise buyers often prefer bank transfer or invoice billing for compliance and renewal control.

Can account restrictions delay a migration project?

Yes. Verification delays, quota limits, or region restrictions can block task creation even when the database side is ready.

What I would do if this were my migration

If the DTS task stopped today, I would handle it in this order:

1. Pull the exact primary key value from the DTS error message.
2. Compare the source and target row directly.
3. Decide which row is the business truth, not just which one is technically newer.
4. Fix the target or source data once, then resume the task.
5. Review the account, billing, and permission setup so the task does not get blocked again by KYC, funding, or quota problems.

If you are still in the purchase stage, set up the account correctly before the cutover window. If you are already in the middle of a failed sync, focus first on the row-level conflict, then check whether the cloud account can actually support the renewal, billing, and region setup you need for the long run.