Members
ReplicaAckPolicy :Number
A replicated environment makes it possible to increase the application's
transaction commit guarantees by committing changes to its replicas on the
network. ReplicaAckPolicy defines the policy for how such network commits
are handled.
Type:
Properties:
Name |
Type |
Description |
ALL |
Number
|
All replicas must acknowledge that they have
committed the transaction. |
NONE |
Number
|
No transaction commit acknowledgments are required
and the master will never wait for replica acknowledgments. |
SIMPLE_MAJORITY |
Number
|
A simple majority of replicas must
acknowledge that they have committed the transaction. |
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ReturnChoice :Number
Specifies whether to return the row value, version, both or neither.
For best performance, it is important to choose only the properties that are
required. The store is optimized to avoid I/O when the requested properties
are in cache.
Type:
Properties:
Name |
Type |
Description |
ALL |
Number
|
Return both the value and the version. |
NONE |
Number
|
Do not return the value or the version. |
VALUE |
Number
|
Return the value only. |
VERSION |
Number
|
Return the version only. |
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SimpleConsistency :Number
Used to provide consistency guarantees for read operations.
In general, read operations may be serviced either at a Master or Replica
node. When serviced at the Master node, consistency is always absolute. If
absolute consistency is required, ABSOLUTE may be specified to force the
operation to be serviced at the Master. For other types of consistency, when
the operation is serviced at a Replica node, the transaction will not begin
until the consistency policy is satisfied. The Consistency is specified as
an argument to all read operations, for example, get.
Type:
Properties:
Name |
Type |
Description |
ABSOLUTE |
Number
|
A consistency policy that requires that a
transaction be serviced on the Master so that consistency is absolute. |
NONE_REQUIRED |
Number
|
A consistency policy that lets a
transaction on a replica using this policy proceed regardless of the state
of the Replica relative to the Master. |
NONE_REQUIRED_NO_MASTER |
Number
|
A consistency policy that
requires that a read operation be serviced on a replica; never the Master. |
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SyncPolicy :Number
Defines the synchronization policy to be used when committing a transaction.
High levels of synchronization offer a greater guarantee that the
transaction is persistent to disk, but the tradeoff is lower performance.
Type:
Properties:
Name |
Type |
Description |
NO_SYNC |
Number
|
Do not write or synchronously flush the log on
transaction commit. |
SYNC |
Number
|
Write and synchronously flush the log on transaction
commit. |
WRITE_NO_SYNC |
Number
|
Write but do not synchronously flush the
log on transaction commit. |
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TimeUnit :Number
A time unit in HOURS or DAYS
Type:
Properties:
Name |
Type |
Description |
HOURS |
Number
|
|
DAYS |
Number
|
|
HOURS |
Number
|
|
DAYS |
Number
|
|
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Methods
AuthenticationFailureException()
This exception is thrown if an application passes invalid credentials to
an authentication operation.
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AuthenticationRequiredException()
This exception is thrown when a secured operation is attempted and the
client is not currently authenticated. It can occur if login credentials
were specified, but the login session has expired, requiring that the client
reauthenticate itself.
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ConsistencyException()
Returned when a single or multiple-operation transaction fails because the
specified Consistency could not be met, within the allowed timeout period.
The likelihood of this exception being thrown depends on the specified
Consistency and the general health of the KVStore system. The default
consistency policy is SimpleConsistency.NONE_REQUIRED. With
SimpleConsistency.NONE_REQUIRED (the default),
SimpleConsistency.NONE_REQUIRED_NO_MASTER, or SimpleConsistency.ABSOLUTE,
this exception will never be thrown.
If the client overrides the default and specifies a TimeConsistency or
VersionConsistency setting, then this exception will be thrown when the
specified consistency requirement cannot be satisfied within the timeout
period associated with the consistency setting. If this exception is
encountered frequently, it indicates that the consistency policy
requirements are too strict and cannot be met routinely given the load
being placed on the system and the hardware resources that are available
to service the load.
Depending on the nature of the application, when this exception is thrown
the client may wish to
- retry the read operation,
- fall back to using a larger timeout or a less restrictive consistency
setting (for example, SimpleConsistency.NONE_REQUIRED), and resume using
the original consistency setting at a later time, or
- give up and report an error at a higher level.
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DurabilityException()
Returned when write operations cannot be initiated because a quorum of
Replicas as determined by the Durability.ReplicaAckPolicy was not available.
The likelihood of this exception being thrown depends on the number of nodes
per replication group, the rate of node failures and how quickly a failed
node is restored to operation, and the specified ReplicaAckPolicy. The
ReplicaAckPolicy for the default durability policy is
Durability.ReplicaAckPolicy.SIMPLE_MAJORITY. With SIMPLE_MAJORITY,
this exception is thrown only when the majority of nodes in a replication
group are unavailable, and in a well-maintained KVStore system with at least
three nodes per replication group this exception should rarely be thrown.
If the client overrides the default and specifies
Durability.ReplicaAckPolicy.ALL, then this exception will be thrown when any
node in a replication group is unavailable; in other words, it is much more
likely to be thrown. If the client specifies
Durability.ReplicaAckPolicy.NONE, then this exception will never be thrown.
When this exception is thrown the KVStore service will perform administrative
notifications so that actions can be taken to correct the problem. Depending
on the nature of the application, the client may wish to:
- retry the write operation immediately,
- fall back to a read-only mode and resume write operations at a later time,
or
- give up and report an error at a higher level.
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FaultException()
Used to indicate an error condition that cannot normally be handled by the
caller of the method, except by retrying the operation.
When the error occurred remotely and was due to an internally defined server
exception.
When the error occurred remotely, it will have already been logged and
reported on a remote KVStore node and will be available to administrators.
However, to correlate client and server errors and to make error information
easily accessible on the client, it is good practice to also log the error
locally. Errors that originated locally are not automatically logged and
available to administrators, and the client application is responsible for
reporting them.
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IllegalArgumentException()
Returned when any of the arguments sent to the server is wrong.
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readConfiguration(filename) → {Configuration}
Tries to read a file with a ProxyConfiguration object
Parameters:
Name |
Type |
Description |
filename |
string
|
the full path for the file |
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Returns:
-
Type
-
Configuration
RequestLimitException()
Thrown when a request cannot be processed because it would exceed the
maximum number of active requests for a node as configured by
-request-limit.
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RequestTimeoutException()
Returned when a request cannot be processed because the configured timeout
interval is exceeded.
The default timeout interval is five seconds, and this exception should
rarely be thrown.
Note that the durability of an update operation is uncertain if it results
in a RequestTimeoutException being thrown. The changes requested by the
update may or may not have been committed to the master or propagated to one
or more replicas. Applications may want to retry the update operation if it
is idempotent, or perform read operations to determine the outcome of the
previous update.
Note also that if the consistency specified for a read operation is
Consistency.NONE_REQUIRED_NO_MASTER, then this exception will be thrown
if the operation is attempted when the only node available is the Master.
Depending on the nature of the application, when this exception is thrown
the client may wish to:
- retry the operation,
- fall back to using a larger timeout interval, and resume using the
original timeout interval at a later time, or
- give up and report an error at a higher level.
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startProxy(configuration, callback)
Starts a proxy with the specified configuration.
Parameters:
Name |
Type |
Description |
configuration |
Configuration
|
The configuration object used to
start or connect to a proxy. |
callback |
function
|
Function called after the proxy is started. |
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stopProxy(proxyConfiguration, callback)
Shutdown the proxy. If a proxy is running, this method will shutdown it.
Parameters:
Name |
Type |
Description |
proxyConfiguration |
ProxyConfiguration
|
the configuration used to
start the proxy. |
callback |
function
|
Function called after trying to shutdown the
proxy. |
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TableOpExecutionException()
Used to indicate a failure in executeUpdates.
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UnauthorizedException()
This exception is thrown from methods where an authenticated user is
attempting to perform an operation for which they are not authorized.
An application that receives this exception typically should not retry the
operation.
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UnknownException()
This exception is thrown when a non recognized error is received from the
proxy.
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Type Definitions
cancelCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
bool
|
A flag indicating if the process could be canceled. |
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closeIteratorCallback(error)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
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deleteCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
DeleteResult
|
The result associated with this
operation. |
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executeFutureCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
ExecutionFuture
|
A statementResult object with information
about the process. |
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executeUpdatesCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
UpdateResult
|
A statementResult object with information
about the process. |
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getCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
ExecutionFuture
|
A statementResult object with information
about the process. |
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getCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
GetResult
|
The result associated with this operation. |
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iteratorCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
Iterator
|
An Iterator object with the item results for this
call. |
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multiDeleteCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
Number
|
The number of rows deleted by this
operation. |
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multiGetCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
MultiGetResult
|
The result associated with this
operation. |
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multiGetKeysCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
MultiGetKeyResult
|
The result associated with this
operation. |
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openCallback(error)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
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putCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
PutResult
|
The result associated with this
operation. |
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rowCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
ReturnRow
|
A result Object object with the row and
metadata as result. |
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shutdownProxyCallback(error)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
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streamCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
Readable
|
A Stream object with the result of this operation. |
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updateStatusCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
ExecutionFuture
|
A statementResult object with information
about the process. |
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versionCallback(error, result)
Parameters:
Name |
Type |
Description |
error |
Error
|
The error returned by the operation, if any, null
otherwise. |
result |
String
|
A String with the result of this operation. |
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