Apama 10.3.1 | Apama Documentation | Deploying and Managing Apama Applications | Correlator Utilities Reference | Starting the correlator | Descriptions of correlator status log fields
 
Descriptions of correlator status log fields
The correlator sends information to the main correlator log file every five seconds (the default behavior) or at an interval that you specify with the --logQueueSizePeriod option when you start the correlator.
There are one or two lines in the log file, depending on whether persistence is enabled or not:
*The line starting with Correlator Status: is always shown. See Correlator status for detailed information on the log fields that are shown in this line.
*The line starting with Persistence Status: is only shown when persistence has been enabled. See Persistence status for detailed information on the log fields that are shown in this line.
Note: Correlators with correlator-integrated messaging for JMS enabled send additional information to the main log file of the correlator. For details on this information, see Logging correlator-integrated messaging for JMS status.
Correlator status
When logging at INFO level, this information contains the following:
Correlator Status: sm=11 nctx=1 ls=60 rq=0 iq=0 oq=0 icq=0 lcn="<none>" lcq=0 lct=0.0 rx=5 tx=17 rt=31 nc=2 vm=325556 pm=81068 runq=0 si=915.3 so=0.0 srn="<none>" srq=0 jvm=0
Where the fields have the following meanings (see List of correlator status statistics for more information):
Field
Meaning
Trend
sm
The number of monitor instances, also known as sub-monitors.
Steady
nctx
The number of contexts in the correlator, including the main context.
Steady
ls
The number of listeners in all contexts. This includes on statements and active stream source templates.
Steady
rq
The sum of routed events on the route queues of all contexts.
Low
iq
The number of executors on the input queues of all contexts. As well as events, this can include clock ticks, spawns, injections and other operations. A context in an infinite loop will grow by 10 per second due to clock ticks. Every context has an input queue, which by default is a maximum of 20,000 entries.
Low
oq
The number of events waiting on output queues to be dispatched to any connected external consumers/receivers.
Low
icq
The number of events on the input queues of all public contexts. See also About context properties for information on the receiveInput flag.
Low
lcn
The name of the slowest context. This may or may not be a public context.
None
lcq
The number of events on the slowest context's queue, as identified by the name of the slowest context.
Low
lct
For the context identified by the slowest context name, this is the time difference in seconds between its current logical time and the most recent time tick added to its input queue.
Low
rx
The number of events that the correlator has received from external sources since the correlator started. This includes connectivity plug-ins, correlator-integrated JMS, engine_send, other correlators connected with engine_connect, dashboard servers, the IAF, and events that are not parsed correctly. This number excludes events sent within the correlator from EPL monitors or EPL plug-ins.
Increasing
tx
The number of events that have been delivered to external consumers/receivers. This counts for each external consumer/receiver an event is sent to. It counts the number of deliveries of events.
Increasing
rt
The number of events that have been routed across all contexts since the correlator was started.
Increasing
nc
The number of external consumers/receivers connected to receive emitted events. This includes connectivity plug-ins, correlator-integrated JMS, engine_receive, or correlators connected using engine_connect.
Steady
vm
Virtual memory in kilobytes.
Steady
pm
Physical memory in kilobytes.
Steady
runq
The number of contexts on the run queue. These are the contexts that have work to do but are not currently running.
Low
si
The number of pages per second that are being read from swap space. If this is greater than zero, it may indicate that the machine is under-provisioned, which can lead to reduced performance, connection timeouts and other problems. Consider adding more memory, reducing the number of other processes running on the machine, or partitioning your Apama application across multiple machines.
Low
so
The number of pages per second that are being written to swap space. If this is greater than zero, it may indicate that the machine is under-provisioned, which can lead to reduced performance, connection timeouts and other problems. Consider adding more memory, reducing the number of other processes running on the machine, or partitioning your Apama application across multiple machines.
Low
srn
The name of the consumer/receiver with the largest number of incoming events waiting to be processed. This is the slowest non-context consumer/receiver of events, which can be an external receiver or an EPL plug-in.
None
srq
The number of events on the slowest consumer's/receiver's queue, as identified by the name of the slowest consumer/receiver.
Low
jvm
The sum of all memory used by the Java virtual machine (JVM) which is embedded in the correlator (that is, the used heap memory, the used non-heap memory, and the used buffer pool memory). The value is in megabytes. If the JVM is disabled, the value will be 0.
Steady
Persistence status
If persistence is enabled, information such as the following is also shown when logging at INFO level:
Persistence Status: numSnapshots=25 lastSnapshotTime=1516203192 snapshotWaitTimeEwmaMillis=0.029071 commitTimeEwmaMillis=3.459181 lastSnapshotRowsChangedEwma=8
Where the fields have the following meanings (see List of correlator status statistics for more information):
Field
Meaning
Trend
numSnapshots
The number of persistence snapshots taken since the correlator started.
Increasing
lastSnapshotTime
The UNIX timestamp of the last completed snapshot.
Increasing
snapshotWaitTimeEwmaMillis
An exponentially weighted moving average (EWMA) of the time in milliseconds taken to wait for a snapshot.
Varies
commitTimeEwmaMillis
An exponentially weighted moving average (EWMA) of the time in milliseconds taken to commit to the database.
Varies
lastSnapshotRowsChangedEwma
An exponentially weighted moving average (EWMA) of the number of rows changed per snapshot.
Varies

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