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START_REPLICATION

Requires replication connection.
This command can only be executed on a walsender backend which can be started by establishing a replication connection. A replication connection can be created by passing the parameter replication=database in the connection string. Refer to examples section.

Synopsis

Use the START_REPLICATION command to start streaming changes from a logical replication slot.

Syntax

start_replication ::= START_REPLICATION SLOT slot_name LOGICAL 
                      log_sequence_number 
                      [ ( start_replication_option [ , ... ] ) ]

log_sequence_number ::= text_literal

start_replication

START_REPLICATIONSLOTslot_nameLOGICALlog_sequence_number(,start_replication_option)

log_sequence_number

text_literal

Semantics

Instructs the server to start streaming WAL for logical replication. The output plugin associated with the selected slot is used to process the output for streaming.

slot_name

The name of the slot to stream changes from. This parameter is required, and must correspond to an existing logical replication slot created with CREATE_REPLICATION_SLOT.

log_sequence_number

The log sequence number from where to start the streaming from.

start_replication_option_name

The name of an option passed to the slot's logical decoding plugin.

The applicable options accepted by the command depends on the output plugin of the replication slot. They can be viewed in the respective documentation of the output plugin itself.

For pgoutput and yboutput, check the section 53.5.1. Logical Streaming Replication Parameters in the PG documentation.

For wal2json, refer to the plugin documentation.

start_replication_option_value

Optional value, in the form of a string constant, associated with the specified option.

Example

We need to follow a few steps before we can start streaming from a replication slot. Assume that a table with name users already exists in the database yugabyte.

Create a publication mypublication which includes the table users.

yugabyte=# CREATE PUBLICATION mypublication FOR TABLE users;

The creation and replication from a slot requires a replication connection. Establish a replication connection to the database yugabyte.

bin/ysqlsh "dbname=yugabyte replication=database"

Create a replication slot with name test_slot and output plugin pgoutput.

yugabyte=# CREATE_REPLICATION_SLOT test_slot LOGICAL pgoutput;

Start replication from the test_slot replication slot starting from LSN 0/2. We also pass the publication_names parameter with value mypublication to the output plugin. publication_names is an output plugin parameter that is accepted by both pgoutput and yboutput to determine the tables to stream the data from.

yugabyte=# START_REPLICATION test_slot LOGICAL 0/2 publication_names 'mypublication';

See also