If you start it using the standard startup script, Cassandra will listen for connections on port 8080 (port 7199 starting in 0.8.0-beta1) to view and tweak variables which it exposes via JMX. This may be helpful for debugging and monitoring. See also JmxGotchas.
The MemtableThresholds page describes how to use Jconsole as a client for this.
Domain |
Source Location |
Type |
Keyspace |
Cache |
Attributes |
Operations |
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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||||
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||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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||||
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||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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||||
|
||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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|
||||
|
||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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||||
|
||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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||||
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||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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||||
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||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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||||
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||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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|
||||
|
||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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||||
|
||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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|
||||
|
||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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|
||||
|
||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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|
||||
|
||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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||||
|
||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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||||
|
||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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|
||||
|
||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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|
||||
|
||||||
./concurrent/JMXEnabledThreadPoolExecutorMBean.java |
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|
||||
|
||||||
./db/CommitLogExecutorServiceMBean.java |
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|
||||
|
||||||
./db/CompactionManagerMBean.java |
|
|
BytesCompacted |
|||
|
||||||
./gms/FailureDetectorMBean.java |
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|||
./service/StorageServiceMBean.java |
|
|
CurrentGenerationNumber |
|||
clearSnapshot |
||||||
./service/StorageProxyMBean.java |
|
|
RangeOperations |
|||
|
||||||
./streaming/StreamingService.java |
|
|
||||
org.apache.cassandra.concurrent
All org.apache.cassandra.concurrent Types are thread pool executors which have Attributes ActiveCount, CompletedTasks and PendingTasks. They are viewable from the command line with {{'}}nodeprobe tpstats{{'}}.
They are generally defined as follows :
org.apache.cassandra.concurrent.<THREADPOOL>.Attributes.ActiveCount
Type |
Units |
Range |
Notes |
int |
tasks |
integer >=0 |
The current number of running tasks. |
org.apache.cassandra.concurrent.<THREADPOOL>.Attributes.CompletedTasks
Type |
Units |
Range |
Notes |
long |
tasks |
integer >=0 |
The number of completed tasks since executor creation. |
org.apache.cassandra.concurrent.<THREADPOOL>.Attributes.PendingTasks
Type |
Units |
Range |
Notes |
long |
tasks |
integer >=0 |
The number of tasks waiting in the queue to be executed. |
org.apache.cassandra.concurrent.AE-SERVICE-STAGE
This thread pool is single threaded.
Per src/java/org/apache/cassandra/service/AntiEntropyService.java,
AntiEntropyService encapsulates "validating" (hashing) individual column families, exchanging MerkleTrees with remote nodes via a TreeRequest/Response conversation, and then triggering repairs for disagreeing ranges. Tree comparison and repair triggering occur in the single threaded AE_SERVICE_STAGE.
org.apache.cassandra.concurrent.CONSISTENCY-MANAGER
This pool has 4 threads, which is hardcoded per src/java/org/apache/cassandra/service/StorageService.java,
private static int consistencyThreads_ = 4; // not configurable
The CONSISTENCY-MANAGER executor is responsible for passive read repair, for example after a read with ConsistencyLevel.ONE.
Per src/java/org/apache/cassandra/service/StorageService.java,
/* This thread pool does consistency checks when the client doesn't care about consistency */
org.apache.cassandra.concurrent.FILEUTILS-DELETE-POOL
This thread pool is single threaded. Code is defined in src/java/org/apache/cassandra/io/DeletionService.java. This executor is responsible for deleting files, such as obsolete sstables and obsolete commitlog segments.
org.apache.cassandra.concurrent.FLUSH-SORTER-POOL
This thread pool is multi-threaded, with between 1 and Runtime.getRuntime().availableProcessors() threads in the pool.
See Also : FLUSH-WRITER-POOL and MEMTABLE-POST-FLUSHER. Per src/java/org/apache/cassandra/db/ColumnFamilyStore.java,
* submitFlush first puts [Binary]Memtable.getSortedContents on the flushSorter executor,
* which then puts the sorted results on the writer executor. This is because sorting is CPU-bound,
* and writing is disk-bound; we want to be able to do both at once. When the write is complete,
* we turn the writer into an SSTableReader and add it to ssTables_ where it is available for reads.
*
* For BinaryMemtable that's about all that happens. For live Memtables there are two other things
* that switchMemtable does (which should be the only caller of submitFlush in this case).
* First, it puts the Memtable into memtablesPendingFlush, where it stays until the flush is complete
* and it's been added as an SSTableReader to ssTables_. Second, it adds an entry to commitLogUpdater
* that waits for the flush to complete, then calls onMemtableFlush. This allows multiple flushes
* to happen simultaneously on multicore systems, while still calling onMF in the correct order,
* which is necessary for replay in case of a restart since CommitLog assumes that when onMF is
* called, all data up to the given context has been persisted to SSTables.
org.apache.cassandra.concurrent.FLUSH-WRITER-POOL
This thread pool is multi-threaded, with between 1 and Runtime.getRuntime().availableProcessors() threads in the pool.
See Also : FLUSH-SORTER-POOL and MEMTABLE-POST-FLUSHER. Per src/java/org/apache/cassandra/db/ColumnFamilyStore.java,
* submitFlush first puts [Binary]Memtable.getSortedContents on the flushSorter executor,
* which then puts the sorted results on the writer executor. This is because sorting is CPU-bound,
* and writing is disk-bound; we want to be able to do both at once. When the write is complete,
* we turn the writer into an SSTableReader and add it to ssTables_ where it is available for reads.
*
* For BinaryMemtable that's about all that happens. For live Memtables there are two other things
* that switchMemtable does (which should be the only caller of submitFlush in this case).
* First, it puts the Memtable into memtablesPendingFlush, where it stays until the flush is complete
* and it's been added as an SSTableReader to ssTables_. Second, it adds an entry to commitLogUpdater
* that waits for the flush to complete, then calls onMemtableFlush. This allows multiple flushes
* to happen simultaneously on multicore systems, while still calling onMF in the correct order,
* which is necessary for replay in case of a restart since CommitLog assumes that when onMF is
* called, all data up to the given context has been persisted to SSTables.
org.apache.cassandra.concurrent.GMFD
This thread pool is single threaded. Executor for the Gossiper.
org.apache.cassandra.concurrent.HINTED-HANDOFF-POOL
This thread pool is single threaded.
Per src/java/org/apache/cassandra/db/HintedHandOffManager.java,
* For each table (keyspace), there is a row in the system hints CF. * SuperColumns in that row are keys for which we have hinted data. * Subcolumns names within that supercolumn are host IPs. Subcolumn values are always empty. * Instead, we store the row data "normally" in the application table it belongs in. * * So when we deliver hints we look up endpoints that need data delivered * on a per-key basis, then read that entire row out and send it over.
org.apache.cassandra.concurrent.LB-OPERATIONS
This thread pool is single threaded.
See Also : LB-TARGET. Per src/java/org/apache/cassandra/service/StorageLoadBalancer.java,
/* This thread pool is used for initiating load balancing operations */
org.apache.cassandra.concurrent.LB-TARGET
This thread pool is single threaded.
See Also : LB-OPERATIONS. Per src/java/org/apache/cassandra/service/StorageLoadBalancer.java,
/* This thread pool is used by target node to leave the ring. */
org.apache.cassandra.concurrent.LOAD-BALANCER-STAGE
This thread pool is single threaded.
org.apache.cassandra.concurrent.MEMTABLE-POST-FLUSHER
This thread pool is single threaded.
See Also : FLUSH-SORTER-POOL and FLUSH-WRITER-POOL. Per src/java/org/apache/cassandra/db/ColumnFamilyStore.java,
* submitFlush first puts [Binary]Memtable.getSortedContents on the flushSorter executor,
* which then puts the sorted results on the writer executor. This is because sorting is CPU-bound,
* and writing is disk-bound; we want to be able to do both at once. When the write is complete,
* we turn the writer into an SSTableReader and add it to ssTables_ where it is available for reads.
*
* For BinaryMemtable that's about all that happens. For live Memtables there are two other things
* that switchMemtable does (which should be the only caller of submitFlush in this case).
* First, it puts the Memtable into memtablesPendingFlush, where it stays until the flush is complete
* and it's been added as an SSTableReader to ssTables_. Second, it adds an entry to commitLogUpdater
* that waits for the flush to complete, then calls onMemtableFlush. This allows multiple flushes
* to happen simultaneously on multicore systems, while still calling onMF in the correct order,
* which is necessary for replay in case of a restart since CommitLog assumes that when onMF is
* called, all data up to the given context has been persisted to SSTables.
org.apache.cassandra.concurrent.MESSAGE-DESERIALIZER-POOL
This thread pool is multi-threaded, with between 1 and Runtime.getRuntime().availableProcessors() threads in the pool.
Per src/java/org/apache/cassandra/net/MessagingService.java,
// read executor puts messages to deserialize on this.
org.apache.cassandra.concurrent.MESSAGE-STREAMING-POOL
This thread pool is single threaded.
org.apache.cassandra.concurrent.RESPONSE-STAGE
This thread pool is mutli-threaded and has between 1 and Runtime.getRuntime().availableProcessors() threads in the pool.
org.apache.cassandra.concurrent.ROW-MUTATION-STAGE
This thread pool is multi-threaded and has between 1 and concurrectWriters threads in the pool.
Per src/java/org/apache/cassandra/concurrent/StageManager.java,
private static int concurrentWriters_ = 32;
org.apache.cassandra.concurrent.ROW-READ-STAGE
This thread pool is multi-threaded and has between 1 and concurrectReaders threads in the pool.
Per src/java/org/apache/cassandra/concurrent/StageManager.java,
private static int concurrentReaders_ = 8;
org.apache.cassandra.concurrent.STREAM-STAGE
This stage is single threaded.
org.apache.cassandra.db
org.apache.cassandra.db.CommitLog
org.apache.cassandra.db.CommitLog.Attributes.ActiveCount
Type |
Units |
Range |
Notes |
int |
tasks |
>=0 |
The number of tasks which are currently executing. |
org.apache.cassandra.db.CommitLog.Attributes.CompletedTasks
Type |
Units |
Range |
Notes |
long |
tasks |
>=0 |
The number of completed tasks. |
org.apache.cassandra.db.CommitLog.Attributes.PendingTasks
Type |
Units |
Range |
Notes |
long |
tasks |
>=0 |
The number of tasks waiting in the queue to be executed. |
org.apache.cassandra.db.CompactionManager
org.apache.cassandra.db.CompactionManager.Attributes.BytesCompacted
Type |
Units |
Range |
Notes |
java.lang.Long |
bytes |
integer >=0 |
The number of bytes successfully compacted. |
org.apache.cassandra.db.CompactionManager.Attributes.BytesTotalInProgress
Type |
Units |
Range |
Notes |
java.lang.Long |
bytes |
integer >=0 |
FIXME?? : The total size of the SSTables involved in the current compaction. |
org.apache.cassandra.db.CompactionManager.Attributes.ColumnFamilyInProgress
Type |
Units |
Range |
Notes |
java.lang.string |
name |
Any valid Column{{`Family name |
The name of the Column}}`Family currently being compacted. |
org.apache.cassandra.db.CompactionManager.Attributes.MaximumCompactionThreshold
Type |
Units |
Range |
Notes |
int |
SSTables |
>=0 |
The maximum number of SSTables in the compaction queue before compaction kicks off. |
org.apache.cassandra.db.CompactionManager.Attributes.MinimumCompactionThreshold
Type |
Units |
Range |
Notes |
int |
SSTables |
>=0 |
The minimum number of SSTables in the compaction queue before compaction kicks off. |
org.apache.cassandra.db.CompactionManager.Attributes.PendingTasks
Type |
Units |
Range |
Notes |
int |
tasks |
>=0 |
The number of tasks waiting in the queue to be executed. |
org.apache.cassandra.gms
org.apache.cassandra.gms.FailureDetector
org.apache.cassandra.gms.FailureDetector.Operations.dumpInterArrivalTimes
Dump endpoint arrival windows to a file in /var/tmp, per src/java/org/apache/cassandra/gms/FailureDetector.java:
FileOutputStream fos = new FileOutputStream("/var/tmp/output-" + System.currentTimeMillis() + ".dat", true);
org.apache.cassandra.service
org.apache.cassandra.service.StorageService
org.apache.cassandra.service.StorageService.Attributes.CurrentGenerationNumber
Type |
Units |
Range |
Notes |
int |
Generation Number |
>=0 |
The number of the current generation in the Gossiper. |
org.apache.cassandra.service.StorageService.Attributes.LiveNodes
Type |
Units |
Range |
Notes |
java.util.Set |
Nodes |
n/a |
A set of the nodes which are visible and live, from the perspective of this node. |
org.apache.cassandra.service.StorageService.Attributes.LoadMap
Type |
Units |
Range |
Notes |
Example |
java.util.Map |
Nodes,Disk Usage |
n/a |
A map of which nodes have what level of load. |
{10.0.0.130=107.86 GB,10.0.0.41=125.82 GB,10.0.0.176=117.47 GB,10.0.0.15=68.65 GB,10.0.0.91=148.25 GB,10.0.0.165=247.33 GB] |
org.apache.cassandra.service.StorageService.Attributes.LoadString
Type |
Units |
Range |
Notes |
Example |
java.lang.String |
Disk usage |
n/a |
The amount of load on the node being queried. |
127.7 GB |
org.apache.cassandra.service.StorageService.Attributes.OperationMode
Type |
Units |
Range |
Notes |
Examples |
java.lang.String |
Operation mode string |
n/a |
A string describing the current operation mode. (FIXME: wikilink on operation mode?) |
Decommissioned, Joining: getting bootstrap token, Joining: getting load information, Leaving: streaming data to other nodes, Normal, Joining: sleeping " + RING_DELAY + " for pending range setup, Leaving: sleeping " + RING_DELAY + " for pending range setup |
org.apache.cassandra.service.StorageService.Attributes.Token
Type |
Units |
Range |
Notes |
Example |
java.lang.String |
key range start position |
n/a |
A string describing the start of the range of keys this node is responsible for on the ring. |
|
org.apache.cassandra.service.StorageService.Attributes.UnreachableNodes
Type |
Units |
Range |
Notes |
Example |
||
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="093d369a-b21e-4d82-9d4f-d28292ffdc99"><ac:plain-text-body><![CDATA[ |
java.util.Set |
Nodes |
n/a |
A set of the nodes which this node knows about which are currently unreachable. |
[10.0.0.1,10.0.0.2] |
]]></ac:plain-text-body></ac:structured-macro> |
org.apache.cassandra.service.StorageService.Operations.clearSnapshot
Arguments |
Return Type |
Notes |
n/a |
void |
Clear all the snapshots for this node's keyspace. |
Per src/java/org/apache/cassandra/db/Table.java :
String snapshotPath = dataDirPath + File.separator + name + File.separator + SNAPSHOT_SUBDIR_NAME;
...
FileUtils.deleteDir(snapshotDir);
org.apache.cassandra.service.StorageService.Operations.decommission
Arguments |
Return Type |
Notes |
n/a |
void |
Instruct this (live) node to remove itself from the token ring. |
This operation may fail if :
- The node is not a member of the token ring yet.
- There are no other normal nodes in the ring.
- Data is currently moving to the node.
org.apache.cassandra.service.StorageService.Operations.forceTableCleanup
Arguments |
Return Type |
Notes |
n/a |
void |
Trigger a cleanup compaction. Goes over each file and removes the keys that the node is not responsible for, and only keeps keys that this node is responsible for. |
org.apache.cassandra.service.StorageService.Operations.forceTableCompaction
Arguments |
Return Type |
Notes |
n/a |
void |
Trigger a major compaction (of all SSTables on disk). |
org.apache.cassandra.service.StorageService.Operations.forceTableFlush
Argument p1 |
Argument p1 Type |
Argument p2 |
Argument p2 Type |
Return Type |
Notes |
Example |
tableName |
java.lang.String |
columnFamilies |
java.lang.String... |
void |
Flush all memtables for a table and column families. |
|
org.apache.cassandra.service.StorageService.Operations.forceTableRepair
Argument p1 |
Argument p1 Type |
Argument p2 |
Argument p2 Type |
Return Type |
Notes |
Example |
tableName |
java.lang.String |
columnFamilies |
java.lang.String... |
void |
Trigger proactive repair for a table and column families |
|
org.apache.cassandra.service.StorageService.Operations.getLiveNaturalEndpoints
Argument p1 |
Argument p1 Type |
Argument p2 |
Argument p2 Type |
Return Type |
Notes |
Example |
tableName |
java.lang.String |
token |
java.lang.String |
java.lang.String |
Attempts to return N endpoints that are responsible for storing the specified key i.e for replication. |
|
org.apache.cassandra.service.StorageService.Operations.getNaturalEndpoints
Argument p1 |
Argument p1 Type |
Argument p2 |
Argument p2 Type |
Return Type |
Notes |
Example |
tableName |
java.lang.String |
token |
java.lang.String |
java.lang.String |
Returns the N endpoints that are responsible for storing the specified key i.e for replication. |
|
org.apache.cassandra.service.StorageService.Operations.getRangeToEndPointMap
Argument p1 |
Argument p1 Type |
Return Type |
Notes |
Example |
keyspace |
java.lang.String |
java.lang.String |
For a keyspace, return the ranges and corresponding hosts for a given keyspace. |
|
org.apache.cassandra.service.StorageService.Operations.loadBalance
Arguments |
Return Type |
Notes |
n/a |
void |
Generate new auto-assigned token for this node, between the two most heavily loaded nodes. |
org.apache.cassandra.service.StorageService.Operations.move
Argument p1 |
Argument p1 Type |
Return Type |
Notes |
keyspace |
java.lang.String |
void |
Move this node to a new token, specified as the argument. |
This operation may fail if :
- The target token is already owned by another node.
- Data is currently moving to this node.
org.apache.cassandra.service.StorageService.Operations.removeToken
Argument p1 |
Argument p1 Type |
Return Type |
Notes |
keyspace |
java.lang.String |
void |
Remove the specified token from the ring. Used on a live node to remove the token of a dead node from all nodes in the ring. |
This operation may fail if :
- There is a live node which owns this token.
org.apache.cassandra.service.StorageService.Operations.setLog4jLevel
Argument p1 |
Argument p1 Type |
Argument p2 |
Argument p2 Type |
Return Type |
Notes |
Example |
classQualifier |
java.lang.String |
rawLevel |
java.lang.String |
void |
Set the level of logging in Log4j. |
DEBUG INFO WARN ERROR FATAL ALL OFF - http://jakarta.apache.org/log4j/docs/api/index.html |
org.apache.cassandra.service.StorageService.Operations.takeAllSnapshot
Argument p1 |
Argument p1 Type |
Return Type |
Notes |
Example |
tag |
java.lang.String or null |
void |
Take a snapshot of all keyspaces on this node and optionally name it with a (non-null) tag name. |
|
org.apache.cassandra.service.StorageService.Operations.takeSnapshot
Argument p1 |
Argument p1 Type |
Argument p2 |
Argument p2 Type |
Return Type |
Notes |
Example |
tableName (Keyspace Name) |
java.lang.String |
tag |
java.lang.String or null |
void |
Take a snapshot of a keyspace and optionally name it with a (non-null) tag name. |
|
org.apache.cassandra.service.StorageProxy
org.apache.cassandra.service.StorageProxy.Attributes.RangeOperations
Type |
Units |
Range |
Notes |
long |
Operations |
>=0 |
The number of range operations since executor start. |
org.apache.cassandra.service.StorageProxy.Attributes.ReadOperations
Type |
Units |
Range |
Notes |
long |
Operations |
>=0 |
The number of read operations since executor start. |
org.apache.cassandra.service.StorageProxy.Attributes.RecentRangeLatencyMicros
Type |
Units |
Range |
Notes |
double |
Microseconds |
>=0 |
The latency of range operations since the last time this attribute was read. |
See Also : RecentReadLatencyMicros, RecentWriteLatencyMicros.
Per src/java/org/apache/cassandra/utils/Latency{{`Tracker.}}`java/getRecentLatencyMicros :
long ops = opCount.get();
long n = totalLatency.get();
return ((double)n - lastLatency) / (ops - lastOpCount);
...
lastLatency = n;
lastOpCount = ops;
org.apache.cassandra.service.StorageProxy.Attributes.RecentReadLatencyMicros
Type |
Units |
Range |
Notes |
double |
Microseconds |
>=0 |
The latency of range operations since the last time this attribute was read. |
See Also RecentRangeLatencyMicros, RecentWriteLatencyMicros.
org.apache.cassandra.service.StorageProxy.Attributes.RecentWriteLatencyMicros
Type |
Units |
Range |
Notes |
double |
Microseconds |
>=0 |
The latency of write operations since the last time this attribute was read. |
See Also : RecentRangeLatencyMicros, RecentReadLatencyMicros.
org.apache.cassandra.service.StorageProxy.Attributes.TotalRangeLatencyMicros
Type |
Units |
Range |
Notes |
long |
Microseconds |
>=0 |
The latency of all range operations since executor start. |
org.apache.cassandra.service.StorageProxy.Attributes.TotalReadLatencyMicros
Type |
Units |
Range |
Notes |
long |
Microseconds |
>=0 |
The latency of all read operations since executor start. |
org.apache.cassandra.service.StorageProxy.Attributes.TotalWriteLatencyMicros
Type |
Units |
Range |
Notes |
long |
Microseconds |
>=0 |
The latency of all write operations since executor start. |
org.apache.cassandra.service.StorageProxy.Attributes.WriteOperations
Type |
Units |
Range |
Notes |
long |
Operations |
>=0 |
The number of write operations since executor start. |
org.apache.cassandra.streaming
org.apache.cassandra.streaming.StreamingService
org.apache.cassandra.streaming.StreamingService.Attributes.Status
Type |
Units |
Range |
Notes |
Example |
java.lang.String |
Status string |
n/a |
A string describing the current state of the StreamingService. |
Flushing memtables for <tableName>, Performing anticompaction, Sending a stream initiate message to <target>, Done with transfer to <target> |
org.apache.cassandra.streaming.StreamingService.Attributes.StreamDestinations
Type |
Units |
Range |
Notes |
Example |
java.lang.Set |
Nodes |
n/a |
A set of the nodes this node is currently streaming to. |
|
org.apache.cassandra.streaming.StreamingService.Attributes.StreamSources
Type |
Units |
Range |
Notes |
Example |
java.lang.Set |
Nodes |
n/a |
A set of the nodes this node is currently streaming from. |
|
org.apache.cassandra.streaming.StreamingService.Operations.getIncomingFiles
Argument p1 |
Argument p1 Type |
Return Type |
Notes |
Example |
node |
java.lang.String |
java.Util.List |
Given a node as an argument, return a List of filenames, current position in the file and how many total bytes are expected in the stream. Shows incoming streams only. |
|
See Also : getOutgoingFiles.
Per src/java/org/apache/cassandra/streaming/StreamingService.java :
files.add(String.format("%s %d/%d", f.getFilename(), f.getPtr(), f.getExpectedBytes()));
org.apache.cassandra.streaming.StreamingService.Operations.getOutgoingFiles
Argument p1 |
Argument p1 Type |
Return Type |
Notes |
Example |
node |
java.lang.String |
java.Util.List |
Given a node as an argument, return a List of filenames, current position in the file and how many total bytes are expected in the stream. Shows outgoing streams only. |
|
See Also : getIncomingFiles.