CONFIGURATION.md

Global configuration properties

Property	Default	Description
client.id	rdkafka	Client identifier.
metadata.broker.list		Initial list of brokers. The application may also use rd_kafka_brokers_add() to add brokers during runtime.
message.max.bytes	4000000	Maximum transmit message size.
receive.message.max.bytes	100000000	Maximum receive message size. This is a safety precaution to avoid memory exhaustion in case of protocol hickups. The value should be at least fetch.message.max.bytes * number of partitions consumed from.
metadata.request.timeout.ms	60000	Non-topic request timeout in milliseconds. This is for metadata requests, etc.
topic.metadata.refresh.interval.ms	10000	Topic metadata refresh interval in milliseconds. The metadata is automatically refreshed on error and connect. Use -1 to disable the intervalled refresh.
topic.metadata.refresh.fast.cnt	10	When a topic looses its leader this number of metadata requests are sent with topic.metadata.refresh.fast.interval.ms interval disregarding the topic.metadata.refresh.interval.ms value. This is used to recover quickly from transitioning leader brokers.
topic.metadata.refresh.fast.interval.ms	250	See topic.metadata.refresh.fast.cnt description
debug		A comma-separated list of debug contexts to enable: all,generic,broker,topic,metadata,producer,queue,msg
socket.timeout.ms	60000	Timeout for network requests.
socket.send.buffer.bytes	0	Broker socket send buffer size. System default is used if 0.
socket.receive.buffer.bytes	0	Broker socket receive buffer size. System default is used if 0.
broker.address.ttl	300000	How long to cache the broker address resolving results.
statistics.interval.ms	0	librdkafka statistics emit interval. The application also needs to register a stats callback using rd_kafka_conf_set_stats_cb(). The granularity is 1000ms. A value of 0 disables statistics.
error_cb		Error callback (set with rd_kafka_conf_set_error_cb())
stats_cb		Statistics callback (set with rd_kafka_conf_set_stats_cb())
opaque		Application opaque (set with rd_kafka_conf_set_opaque())
queued.min.messages	100000	Minimum number of messages that should to be available for consumption by application.
fetch.wait.max.ms	100	Maximum time the broker may wait to fill the response with fetch.min.bytes.
fetch.message.max.bytes	1048576	Maximum number of bytes per topic+partition to request when fetching messages from the broker.
fetch.min.bytes	1	Minimum number of bytes the broker responds with. If fetch.wait.max.ms expires the accumulated data will be sent to the client regardless of this setting.
fetch.error.backoff.ms	500	How long to postpone the next fetch request for a topic+partition in case of a fetch error.
queue.buffering.max.messages	100000	Maximum number of messages allowed on the producer queue.
queue.buffering.max.ms	1000	Maximum time, in milliseconds, for buffering data on the producer queue.
message.send.max.retries	2	How many times to retry sending a failing MessageSet. Note: retrying may cause reordering.
retry.backoff.ms	100	The backoff time in milliseconds before retrying a message send.
compression.codec	none	Compression codec to use for compressing message sets: none, gzip or snappy
batch.num.messages	1000	Maximum number of messages batched in one MessageSet.
dr_cb		Delivery report callback (set with rd_kafka_conf_set_dr_cb())

Topic configuration properties

Property	Default	Description
request.required.acks	1	This field indicates how many acknowledgements the leader broker must receive from ISR brokers before responding to the request: 0=broker does not send any response, 1=broker will wait until the data is written to local log before sending a response, -1=broker will block until message is committed by all in sync replicas (ISRs) before sending response. >1=for any number > 1 the broker will block waiting for this number of acknowledgements to be received (but the broker will never wait for more acknowledgements than there are ISRs).
request.timeout.ms	5000	The ack timeout of the producer request in milliseconds. This value is only enforced by the broker and relies on request.required.acks being > 0.
message.timeout.ms	300000	Local message timeout. This value is only enforced locally and limits the time a produced message waits for successful delivery.
partitioner		Partitioner callback (set with rd_kafka_topic_conf_set_partitioner_cb())
opaque		Application opaque (set with rd_kafka_topic_conf_set_opaque())
auto.commit.enable	true	If true, periodically commit offset of the last message handed to the application. This commited offset will be used when the process restarts to pick up where it left off. If false, the application will have to call rd_kafka_offset_store() to store an offset (optional). NOTE: There is currently no zookeeper integration, offsets will be written to local file according to offset.store.path.
auto.commit.interval.ms	60000	The frequency in milliseconds that the consumer offsets are commited (written) to offset storage.
auto.offset.reset	largest	Action to take when there is no initial offset in offset store or the desired offset is out of range: 'smallest' - automatically reset the offset to the smallest offset, 'largest' - automatically reset the offset to the largest offset, 'error' - trigger an error which is retrieved by consuming messages and checking 'message->err'.
offset.store.path	.	Path to local file for storing offsets. If the path is a directory a filename will be automatically generated in that directory based on the topic and partition.
offset.store.sync.interval.ms	-1	fsync() interval for the offset file, in milliseconds. Use -1 to disable syncing, and 0 for immediate sync after each write.