Statistics

librdkafka optionally emits internal metrics every statistics.interval.ms if a stats_cb has been registered. The stats are provided as a JSON object string.

Note: librdkafka makes use of the system's monotonic clock if one is available, else falls back to the system wall clock time. This clock is represented in number of microseconds since the unix epoch (1970).

Top-level

Field	Type	Example	Description
name	string	"rdkafka#producer-1"	Handle instance name
type	string	"producer"	Instance type (producer or consumer)
ts	int	12345678912345	librdkafka's internal monotonic clock (micro seconds)
replyq	int		Number of ops waiting in queue for application to serve with rd_kafka_poll()
msg_cnt	int		Current number of messages in instance queues
msg_size	int		Current total size of messages in instance queues
msg_max	int		Threshold: maximum number of messages allowed
msg_size_max	int		Threshold: maximum total size of messages allowed
simple_cnt	int		Internal tracking of legacy vs new consumer API state
brokers	object		Dict of brokers, key is broker name, value is object. See brokers below

brokers

Field	Type	Example	Description
name	string	"example.com:9092/13"	Broker hostname, port and broker id
nodeid	int	13	Broker id (-1 for bootstraps)
state	string		Broker state
stateage	int		Time of last broker state change (librdkafka's clock)
outbuf_cnt	int		Number of requests awaiting transmission to broker
outbuf_msg_cnt	int		Number of messages in outbuf_cnt
waitresp_cnt	int		Number of requests in-flight to broker awaiting response
waitresp_msg_cnt	int		Number of messages in waitresp_cnt
tx	int		Total number of requests sent
txbytes	int		Total number of bytes sent
txerrs	int		Total number of transmission errors
txretries	int		Total number of request retries
req_timeouts	int		Total number of requests timed out
rx	int		Total number of responses received
rxbytes	int		Total number of bytes received
rxerrs	int		Total number of receive errors
rxcorriderrs	int		Total number of unmatched correlation ids in response (typically for timed out requests)
rxpartial	int		Total number of partial messagesets received
zbuf_grow	int		Total number of decompression buffer size increases
buf_grow	int		Total number of buffer size increases
rtt	object		Broker latency / round-trip time. See Window stats below
throttle	object		Broker throttling time. See Window stats below
toppars	object		Metrics for partitions handled by this broker handle. See toppars below

Window stats

Rolling window statistics

Field	Type	Example	Description
min	int		Smallest value
max	int		Largest value
avg	int		Average value
sum	int		Sum of values
cnt	int		Number of value samples

toppars

Per-partition metrics

Field	Type	Example	Description