Newts Monitoring

This section describes the metrics Meridian collects for monitoring the Newts keyspace from org.apache.cassandra.metrics.Keyspace on an Cassandra node.

JMX must be enabled on the Cassandra nodes and made accessible from Meridian to collect these metrics. See Enabling JMX authentication and authorization for details.

The data collection is bound to the agent IP interface with the service name JMX-Cassandra-Newts. The JMXCollector retrieves the MBean entities from the Cassandra node.

All memory table data size

Name Description

AllMemtablesLiveDataSize

Total amount of live data stored in the memtables (2i and pending flush memtables included) that reside off-heap, excluding any data structure overhead.

AllMemtablesOffHeapDataSize

Total amount of data stored in the memtables (2i and pending flush memtables included) that resides off-heap.

AllMemtablesOnHeapDataSize

Total amount of data stored in the memtables (2i and pending flush memtables included) that resides on-heap.

Memtable switch count

Name Description

MemtableSwitchCount

Number of times flush has resulted in the memtable being switched out.

Memtable columns count

Name Description

MemtableColumnsCount

Total number of columns present in the memtable.

Memory table data size

Name Description

MemtableLiveDataSize

Total amount of live data stored in the memtable, excluding any data structure overhead.

MemtableOffHeapDataSize

Total amount of data stored in the memtable that resides off-heap, including column-related overhead and partitions overwritten.

MemtableOnHeapDataSize

Total amount of data stored in the memtable that resides on-heap, including column-related overhead and partitions overwritten.

Read and write latency

Name Description

ReadTotalLatency

Local read metrics

WriteTotalLatency

Local write metrics

Range latency

Name Description

RangeLatency 99th Percentile

Local range slice metrics 99th percentile

Latency

Name Description

CasCommitTotalLatency

Time spent in Casandra commits since process start.

CasPrepareTotalLatency

Time spent in Casandra prepare events since process start.

CasProposeTotalLatency

Time spent in Casandra propose events since process start.

Bloom filter disk space

Name Description

BloomFilterDiskSpaceUsed

Disk space bloom filter uses.

Bloom filter off-heap memory

Name Description

BloomFilterOffHeapMemoryUsed

Off-heap memory bloom filter uses.

Newts memory used

Name Description

CompressionMetadataOffHeapMemoryUsed

Off-heap memory compression metadata uses.

IndexSummaryOffHeapMemoryUsed

Off-heap memory index summary uses.

Pending

Name Description

PendingCompactions

Estimated number of pending compactions for this column family.

PendingFlushes

Estimated number of tasks pending for this column family.

Disk space

Name Description

TotalDiskSpaceUsed

Total disk space used by SSTables belonging to this column family including obsolete ones waiting to be garbage collected.

LiveDiskSpaceUsed

Disk space used by SSTables belonging to this column family.