Policy Class

Transaction policy attributes used in all database commands.
Inheritance Hierarchy


Namespace:  Aerospike.Client
Assembly:  AerospikeClient (in AerospikeClient.dll) Version: (5.1.1)

public class Policy

The Policy type exposes the following members.


Public methodPolicy
Default constructor.
Public methodPolicy(Policy)
Copy constructor.

Public methodSetTimeout
Create a single timeout by setting socketTimeout and totalTimeout to the same value.
Public methodSetTimeouts
Set socketTimeout and totalTimeout. If totalTimeout defined and socketTimeout greater than totalTimeout, set socketTimeout to totalTimeout.

Public fieldcompress
Use zlib compression on command buffers sent to the server and responses received from the server when the buffer size is greater than 128 bytes.

This option will increase cpu and memory usage (for extra compressed buffers), but decrease the size of data sent over the network.

Default: false

Public fieldfailOnFilteredOut
Throw exception if filterExp is defined and that filter evaluates to false (transaction ignored). The AerospikeException will contain result code .

This field is not applicable to batch, scan or query commands.

Default: false

Public fieldCode examplefilterExp
Optional expression filter. If filterExp exists and evaluates to false, the transaction is ignored.

Default: null

Public fieldmaxRetries
Maximum number of retries before aborting the current transaction. The initial attempt is not counted as a retry.

If maxRetries is exceeded, the transaction will abort with AerospikeExceptionTimeout.

WARNING: Database writes that are not idempotent (such as Add()) should not be retried because the write operation may be performed multiple times if the client timed out previous transaction attempts. It's important to use a distinct WritePolicy for non-idempotent writes which sets maxRetries = 0;

Default for read: 2 (initial attempt + 2 retries = 3 attempts)

Default for write: 0 (no retries)

Default for partition scan or query with null filter: 5 (6 attempts. See ScanPolicy comments.)

No default for legacy scan/query. No retries are allowed for these commands.

Public fieldreadModeAP
Read policy for AP (availability) namespaces.

Default: ONE

Public fieldreadModeSC
Read policy for SC (strong consistency) namespaces.

Default: SESSION

Public fieldrecordParser
Alternate record parser.

Default: Use standard record parser.

Public fieldreplica
Replica algorithm used to determine the target node for a single record command. Scan and query are not affected by replica algorithms.


Public fieldsendKey
Send user defined key in addition to hash digest on both reads and writes. If the key is sent on a write, the key will be stored with the record on the server.

Default: false (do not send the user defined key)

Public fieldsleepBetweenRetries
Milliseconds to sleep between retries. Enter zero to skip sleep. This field is ignored when maxRetries is zero. This field is also ignored in async mode.

The sleep only occurs on connection errors and server timeouts which suggest a node is down and the cluster is reforming. The sleep does not occur when the client's socketTimeout expires.

Reads do not have to sleep when a node goes down because the cluster does not shut out reads during cluster reformation. The default for reads is zero.

The default for writes is also zero because writes are not retried by default. Writes need to wait for the cluster to reform when a node goes down. Immediate write retries on node failure have been shown to consistently result in errors. If maxRetries is greater than zero on a write, then sleepBetweenRetries should be set high enough to allow the cluster to reform (>= 3000ms).

Default: 0 (do not sleep between retries)

Public fieldsocketTimeout
Socket idle timeout in milliseconds when processing a database command.

If socketTimeout is zero and totalTimeout is non-zero, then socketTimeout will be set to totalTimeout. If both socketTimeout and totalTimeout are non-zero and socketTimeout > totalTimeout, then socketTimeout will be set to totalTimeout. If both socketTimeout and totalTimeout are zero, then there will be no socket idle limit.

If socketTimeout is not zero and the socket has been idle for at least socketTimeout, both maxRetries and totalTimeout are checked. If maxRetries and totalTimeout are not exceeded, the transaction is retried.

For synchronous methods, socketTimeout is the socket SendTimeout and ReceiveTimeout. For asynchronous methods, the socketTimeout is implemented using the AsyncTimeoutQueue and socketTimeout is only used if totalTimeout is not defined.

Default: 30000ms

Public fieldtotalTimeout
Total transaction timeout in milliseconds.

The totalTimeout is tracked on the client and sent to the server along with the transaction in the wire protocol. The client will most likely timeout first, but the server also has the capability to timeout the transaction.

If totalTimeout is not zero and totalTimeout is reached before the transaction completes, the transaction will abort with AerospikeExceptionTimeout.

If totalTimeout is zero, there will be no total time limit.

Default: 0 (no time limit)

See Also