Neptune Lab Mode

You can use Amazon Neptune lab mode to enable new features that are in the current Neptune engine release, but that aren't yet ready for production use and aren't enabled by default. This lets you try out these features in your development and test environments.

Using Neptune Lab Mode

Use the neptune_lab_mode DB cluster parameter to enable or disable features. You do this by including (feature name)=enabled or (feature name)=disabled in the value of the neptune_lab_mode parameter in the DB Cluster Parameter group.

For example, in this engine release you might set the neptune_lab_mode parameter to Streams=disabled, ReadWriteConflictDetection=enabled.

For information about how to edit the DB cluster parameter group for your database, see Editing a Parameter Group. Note that you cannot edit the default DB cluster parameter group; if you are using the default group, you must create a new DB cluster parameter group before you can set the neptune_lab_mode parameter.

curl -G https://your-neptune-endpoint:port/status

{
  "status":"healthy",
  "startTime":"Wed Dec 29 02:29:24 UTC 2021",
  "dbEngineVersion":"development",
  "role":"writer",
  "dfeQueryEngine":"viaQueryHint",
  "gremlin":{"version":"tinkerpop-3.5.2"},
  "sparql":{"version":"sparql-1.1"},
  "opencypher":{"version":"Neptune-9.0.20190305-1.0"},
  "labMode":{
    "ObjectIndex":"disabled",
    "ReadWriteConflictDetection":"enabled"
  },
  "features":{
    "LookupCache":{"status":"Available"},
    "ResultCache":{"status":"disabled"},
    "IAMAuthentication":"disabled",
    "Streams":"disabled",
    "AuditLog":"disabled"
  },
  "settings":{"clusterQueryTimeoutInMs":"120000"}
}

The following features are currently accessed using lab mode:

The OSGP index

Neptune can now maintain a fourth index, namely the OSGP index, which is useful for data sets having a large number of predicates (see Enabling an OSGP Index).

You can enable an OSGP index in a new, empty Neptune DB cluster by setting ObjectIndex=enabled in the neptune_lab_mode DB cluster parameter. An OSGP index can only be enabled in a new, empty DB cluster.

By default, the OSGP index is disabled.

Enabling dictionary garbage collection

Dictionary garbage collection can be enabled for property graph data when neptune-streams is not enabled via the DictionaryGCMode parameter. The concurrency can be controlled via the DictionaryGCConcurrency parameter. See Dictionary garbage collection for more details.

Formalized Transaction Semantics

Neptune has updated the formal semantics for concurrent transactions (see Transaction Semantics in Neptune).

Use ReadWriteConflictDetection as the name in the neptune_lab_mode parameter that enables or disables formalized transaction semantics.

By default, formalized transaction semantics are already enabled. If you want to revert to the earlier behavior, include ReadWriteConflictDetection=disabled in the value set for the DB Cluster neptune_lab_mode parameter.

Extended datetime support

Neptune has extended support for the datetime functionality. To enable datetime with extended formats, include DatetimeMillisecond=enabled in the value set for the DB Cluster neptune_lab_mode parameter.

StrictTimeoutValidation

Default value: enabled (disabled by default prior to Neptune engine release 1.4.0.0)

Allowed values: enabled/disabled

When this parameter is enabled, a per-query timeout value specified as a request option or a query hint cannot exceed the value set globally in the neptune_query_timeout parameter group setting. If the per-query timeout exceeds the global setting, Neptune throws an InvalidParameterException. In engine versions prior to 1.4.0.0, this parameter was disabled by default and had to be explicitly enabled.

This setting can be confirmed in a response on the /status endpoint when the value is disabled.

For more information, see Per-query timeouts.

AccurateQRCMemoryEstimation

Default value: disabled

Allowed values: enabled/disabled

Gremlin query result cache, when enabled, allows caching of query results on the database. By deafult the approximate estimate is used to determine the size of the result cached, with this lab mode param AccurateQRCMemoryEstimation enabled, the size estimation for cached results will use accurate size estimates instead of approximate. This labmode parameter is available starting from Neptune engine release version 1.4.0.0.

UndoLogPurgeConfig

Default value: default

Allowed values: default or aggressive

UndoLogPurgeConfig controls how aggressively Neptune purges undo logs. You enable it through the neptune_lab_mode DB cluster parameter by including UndoLogPurgeConfig=aggressive in the parameter value.

When set to default, Neptune uses the standard number of threads for undo log purging. When set to aggressive, Neptune uses an increased number of threads to expedite the cleanup of undo logs. The number of purge threads scales with the instance size, so pairing this setting with a larger writer instance increases the rate at which undo logs drain.

Undo log purging is performed only by the writer instance. Because neptune_lab_mode is a static parameter, you must reboot the writer instance for a change to UndoLogPurgeConfig to take effect. Beginning with Neptune engine release 1.2.0.0, restarting the writer no longer restarts the read replicas. If you want the setting active on a replica in case of a failover, you must reboot that replica separately.

To revert to standard purging, set UndoLogPurgeConfig=default in the neptune_lab_mode parameter and reboot the writer instance.

After the setting is active, you can track the UndoLogListSize and NumUndoPagesPurged CloudWatch metrics to observe the net drain rate under your production load. This is useful when you need to bring UndoLogListSize below the threshold required before a version upgrade (see Upgrading to engine version 1.2.0.0 or above from a version earlier than 1.2.0.0).