DataStax Graph (DSG) traversal performance settings
dev mode
Use the dev
traversal source while you are experimenting in early DSG use and design.
It allows you to query without creating any indexing, a distinct advantage for exploring your data and data model.
Graph traversal with() options
Use the with()
traversal options to finetune the performance of graph queries.
At various stages of using DSG, different options are more or less useful.
For instance, similar to CQL, an option to allow-filtering
can be useful early in design, but harmful when large datasets are inserted into the database.
Familiarize yourself with the capabilities of the options available.
Timeouts
Timeout settings can cause failure of DSG in a variety of ways, both client-side and server-side.
On the client-side, commands from the Gremlin console can time out before reaching the Gremlin server.
Issuing the command :remote config timeout none
in the Gremlin console allows the default maximum timeout of 3 minutes to be overridden with no time limit.
Any request typed into the Gremlin console is sent to the Gremlin Server, and the console waits for a response before it aborts the request and returns control to the user.
If the timeout is changed to none, the request will never timeout.
This can be useful if the time to send a request to the server and get a return is taking longer than the default timeout, for complex traversals or large datasets.
On the server-side, the cluster-wide timeout settings, realtime_evaluation_timeout_in_seconds
(default: 30 seconds) or analytic_evaluation_timeout_in_minutes
(default: 1008 minutes), are the maximum time to wait for a traversal to evaluate for OLTP or OLAP traversals, respectively.
These settings are found in the dse.yaml file.
If the timeout behavior for traversal evaluation needs to be overridden for a particular graph, evaluation_timeout
can be set on a graph-by-graph basis, to override either the OLTP or OLAP traversal evaluation timeout.
If complex traversals are timing out during execution, changing an appropriate timeout setting should fix the error.
An additional server-side setting that can be adjusted in the dse.yaml file is schema_agreement_timeout_in_ms
(30 seconds), the maximum time to wait for schema versions to agree across a cluster when making schema changes.
If a large schema is submitted to a cluster, especially with indexes defined, this setting may need adjustment before data is submitted to the graph.
Finally, in the dse.yaml file, system_evaluation_timeout_in_seconds
(default: 180 seconds) is defined as the maximum time to wait for a graph system request to evaluate.
Creating or dropping a graph is a system request affected by this setting, which does not interact with the other timeout options.
[[cols="16,10,21"]]
Timeout | Default | Impact |
---|---|---|
:remote config timeout none |
3 minutes |
Lengthen if command transit from Gremlin console to Gremlin Server is timing out. |
realtime_evaluation_timeout_in_seconds |
30 seconds |
Lengthen if the OLTP traversal evaluation is timing out. |
analytic_evaluation_timeout_in_minutes |
1008 minutes |
Lengthen if the OLAP traversal evaluation is timing out. |
evaluation_timeout |
N/A |
Set per-graph to override OLTP or OLAP traversal evaluation timeout. |
schema_agreement_timeout_in_ms |
30 seconds |
Lengthen if a large schema is submitted, especially with indexes. |
system_evaluation_timeout_in_seconds |
180 seconds |
Lengthen if graph system requests are not completing. |