CDC · Event Envelope · Data flow

From PostgreSQL to a Kafka topic

Debezium tails the database log, wraps each change in a standard envelope, and publishes it to Kafka. Click a stage to inspect what's on the wire there.

Connector

Operation

postgresql-c.json

  "before": null,

  "after": {

    "id": 1001,

    "first_name": "Alice",

    "last_name": "Smith",

    "email": "alice@example.com",

    "created_at": 1714000000000

},

  "source": {

    "version": "3.0.5.Final",

    "connector": "postgresql",

    "name": "pgserver1",

    "ts_ms": 1714000000000,

    "snapshot": "false",

    "db": "inventory",

    "sequence": "[null,\"24023128\"]",

    "schema": "public",

    "table": "customers",

    "txId": 555,

    "lsn": 24023128,

    "xmin": null

},

  "op": "c",

  "ts_ms": 1714000000142,

  "transaction": null

Field reference23 fields · hover to align

beforeobject | nullRow state immediately before the change.null for INSERT

afterobject | nullRow state after the change.

idint

first_namestring

last_namestring

emailstring

created_atint

sourceobjectChange origin metadata — log position, connector info, DB coordinates.

versionstringDebezium version that produced the event.

connectorstringConnector type: postgresql, mysql, sqlserver, mongodb.

namestringLogical connector name — also the Kafka topic prefix.

ts_msintWhen the change occurred in the source DB (ms epoch).

snapshotstring"true" | "false" | "last" | "incremental" — whether this event is from a snapshot.

dbstringSource database name.

sequencestringPostgres: [last_commit_lsn, current_lsn] ordering token.

schemastringSource schema (PostgreSQL and SQL Server only).

tablestringSource table name.

txIdintPostgres: transaction id.

lsnintPostgres: WAL byte offset — the exact log position.log position

xminnullPostgres: xmin horizon (rarely populated).

opstringOperation code: c=INSERT, u=UPDATE, d=DELETE, r=snapshot, t=truncate.op = "c"

ts_msint64When Kafka Connect processed the event. For source DB time, read source.ts_ms.

transactionobject | nullTransaction grouping — null unless provide.transaction.metadata=true.