REPLCONF
Introduction and Use Case(s)
REPLCONF
is a command used in Redis replication to configure settings for the replication link between a master and its replicas. It is typically employed during the initial synchronization process or when changing runtime parameters of the replication link. Scenarios include adjusting buffer sizes, setting offsets, and managing acknowledgments.
Syntax
REPLCONF <option> [value]
Parameter Explanations
option
: The configuration option to set. Common options include:listening-port
: Sets the port on which the replica listens.ack
: Acknowledges the receipt of replication data up to a specified offset.getack
: Requests an acknowledgment from the replica.
value
: The value to be assigned to the given option. This varies based on the chosen option.
Return Values
The return value of REPLCONF
depends on the specific option used:
- For
ack
andgetack
options, it typically returns anOK
if successful. - Invalid options or values generate error messages.
Example:
dragonfly> REPLCONF listening-port 6380
OK
dragonfly> REPLCONF ack 12345
OK
Code Examples
dragonfly> REPLCONF listening-port 6380
OK
dragonfly> REPLCONF ack 12345
OK
dragonfly> REPLCONF getack
(null)
Best Practices
- Ensure you understand the exact role each replication configuration parameter plays in your high availability setup.
- Use
REPLCONF
to fine-tune replication performance and reliability based on your network characteristics.
Common Mistakes
Using Incorrect Option Names
Using an unsupported or misspelled option name will result in an error. Always refer to official documentation for supported options.
dragonfly> REPLCONF unkown-option 1234
(error) ERR unknown option 'unkown-option'
Incorrect Value Types
Providing values that do not match the expected type or format for a given option can also lead to errors. Make sure the values align with what the option expects.
FAQs
What happens if I use an unknown option?
Redis will return an error indicating that the option is unknown.
Can REPLCONF
be used by normal clients?
No, it is intended for internal replication management and should be used within the context of Redis’ built-in replication mechanisms.