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Change Data Capture Service FAQs
Answers to common enterprise questions about CDC patterns, platforms, source and target behaviour, latency, schema evolution, reliability, controls, deliverables, pricing and ongoing support.
What is change data capture?
Change data capture, or CDC, is a set of techniques for identifying inserts, updates and deletes in a source system and propagating those changes to downstream platforms without repeatedly re-reading the entire source dataset. The exact mechanism may use database logs, native replication features, timestamps, triggers, queries or platform-specific change streams.
When is CDC a better fit than scheduled batch extraction?
CDC is often appropriate when downstream consumers need fresher data, source systems should avoid repeated full-table scans, data must be synchronized incrementally, migration coexistence requires ongoing replication, or event-driven consumers need a reliable stream of committed changes. Batch remains appropriate where freshness requirements are modest or source constraints make continuous capture unnecessary.
Does CDC guarantee real-time replication?
No. CDC can support low-latency or near-real-time movement, but actual latency depends on the source database, capture method, connector capacity, network, transformations, target throughput, transaction size, backlogs and operational controls. Service expectations should be measured and agreed for the specific architecture rather than assumed.
Which databases and platforms can be supported?
Scope can include commonly used relational databases and cloud data platforms where an appropriate capture mechanism exists. Examples may include PostgreSQL logical decoding, MySQL binary logs, SQL Server CDC, Oracle redo-log based capture, Debezium and Kafka ecosystems, AWS Database Migration Service, Azure Data Factory or Fabric integration capabilities, Google Cloud Datastream, Oracle GoldenGate and other client-selected integration platforms. Final choices depend on supported versions and project requirements.
Can CDC capture inserts, updates and deletes?
Many CDC technologies can capture committed inserts, updates and deletes, but the available event detail varies by source and product. The design should verify before-and-after values, key handling, transaction boundaries, DDL or schema changes, delete representation and target apply behaviour for each required source.
How do you handle initial loads before CDC starts?
A production design normally coordinates an initial snapshot or bulk load with a consistent CDC start position so changes that occur during the load are not lost or duplicated. Cutover logic, checkpoints, reconciliation and replay procedures are documented according to the selected technology and target pattern.
How are ordering, duplicates and retries handled?
The engineering approach can define transaction and partition ordering requirements, stable keys, idempotent consumers, checkpointing, replay boundaries, retry policies and duplicate-handling rules. Exactly-once outcomes should not be claimed unless the complete source-to-target design and technology semantics support them.
How is schema evolution managed in a CDC pipeline?
Schema-change handling is designed explicitly. This can include schema registries or contracts, compatible-change rules, versioned transformations, DDL capture where supported, consumer compatibility checks, deployment gates, rollback plans and alerts for unsupported or breaking changes.
What monitoring should a CDC solution include?
Typical monitoring can include source and target lag, connector health, backlog or queue depth, throughput, error rates, restart counts, checkpoint age, schema-change events, target apply failures, data-quality exceptions and reconciliation status. Alert thresholds should be tied to agreed operating expectations and support ownership.
How are security, privacy and governance addressed?
The design can incorporate least-privilege source access, encryption, secrets management, network controls, masking or filtering where required, data classification, retention, lineage, audit evidence and access governance. Regulatory suitability depends on the client context, data categories, jurisdictions and contractual obligations and should not be assumed from the CDC technology alone.
What deliverables can a CDC engagement include?
Deliverables can include a source and target inventory, CDC suitability assessment, target architecture, connector and topology design, security requirements, schema and contract rules, configured pipelines or replication tasks, test evidence, reconciliation results, observability dashboards, operational runbooks, cutover plans, recovery procedures and knowledge-transfer materials.
How long does a change data capture implementation take?
DataConsultant does not publish a fixed duration for CDC delivery. Timing depends on the number and type of sources and targets, transaction volumes, network access, platform readiness, security approvals, initial-load requirements, schema complexity, transformation logic, testing depth, cutover constraints and operational handover needs.
How is change data capture pricing calculated?
DataConsultant does not publish a fixed fee for this service. Pricing is scope-led and can depend on source and target count, connector technology, data volume and change rate, environment count, high-availability requirements, transformations, security controls, testing, reconciliation, cutover support, documentation, knowledge transfer and ongoing operations. A written quote follows discovery.
Can DataConsultant support CDC after go-live?
Yes. Ongoing support can be scoped for monitoring, incident response, connector upgrades, schema-change coordination, capacity and lag review, reliability improvement, release assurance, reconciliation and runbook maintenance. Responsibilities and service expectations are agreed as part of the operating model.