Dgraph flags

Dgraph flags modify the Dgraph's configuration and behavior.

Important: Dgraph flags are intended for use by Oracle Support only. They are included in this document for completeness.

You can set Dgraph flags by adding them to the DGRAPH_ADDITIONAL_ARG property in bdd.conf in $BDD_HOME/BDD_manager/conf directory, then using the bdd-admin refresh-config script to update the cluster configuration. Any flag included in this list will be set each time the Dgraph starts. For more information, see Refreshing cluster configuration.

Note: Some of the Dgraph flags have the same names as HDFS Agent flags. These must have the same settings as their HDFS Agent counterparts.
Flag Description
? Prints the help message and exits. The help message includes usage information for each Dgraph flag.
-v Enables verbose mode. The Dgraph will print information about each request it receives to either its stdout/stderr file (dgraph.out) or the file set by the --out flag.
--backlog-timeout Specifies the maximum number of seconds that a query is allowed to spend waiting in the processing queue before the Dgraph responds with a timeout message.

The default is 0 seconds.

--bulk_load_port Sets the port on which the Dgraph listens for bulk load ingest requests. This must be the same as the port specified for the HDFS Agent --bulk_load_port flag.

This flag maps to the DGRAPH_BULKLOAD_PORT property in bdd.conf.

--cluster_identity Specifies the cluster identity of the Dgraph running on this node. The syntax is: 
protocol:hostname:dgraph_port:dgraph_bulk_load_port:agent_port

This must be the same as the cluster identity specified for the HDFS Agent --custer_identity flag.

--coordinator Specifies the host and port that ZooKeeper is running on. The syntax is: 
<hostname>:<port>

This must be the same as the value specified for the HDFS Agent --coordinator flag.

--coordinator_auth Obtains the ZooKeeper authentication password from stdin.
--coordinator_index Specifies the index of the Dgraph cluster in the ZooKeeper ensemble. ZooKeeper uses this value to identify the Dgraph cluster. This must be the same as the value specified for the HDFS Agent --coordinator_index flag.

This flag maps to the COORDINATOR_INDEX property in bdd.conf.

--coordinator_session_cache Specifies the name and (optionally) location of the session cache file used by the leader Dgraph. The leader uses this file to resume its last session with ZooKeeper if it exits abnormally.

This file is created when a Dgraph is promoted to leader and deleted when the leader exists normally. If the leader exits abnormally, the file remains on disk so that the leader can resume its last session. Follower Dgraphs don't produce session cache files, and only leaders resume sessions.

The default file is $BDD_HOME/dgraph/clustercache.token. The file location should always be the same to ensure the Dgraph will be able to find it. Additionally, you should avoid modifying the contents of this file.

--export_port Specifies the port on which the Dgraph listens for requests from the HDFS Agent.

This should be the same as the number specified for the HDFS Agent --export_port flag. It should be different from the numbers specified for both the --port and --bulk_load_port flags.

This flag maps to the AGENT_EXPORT_PORT property in bdd.conf.

--help Prints the help message and exits. The help message includes usage information for each Dgraph flag.
--log Specifies the path to the Dgraph request log file. The default file used is dgraph.reqlog.
--memory-limit Specifies the maximum amount of memory (in MB) the Dgraph is allowed to use for processing.

If you do not use this flag, the memory limit is by default set to 80% of the machine's available RAM.

If you specify a limit in MB for this flag, this number is used as the memory consumption limit, for the Dgraph, instead of 80% of the machine's available RAM.

If you specify 0 for this flag, this overrides the default of 80% and means there is no limit on the amount of memory the Dgraph can use for processing.

For a summary of how Dgraph allocates and utilizes memory, see Memory consumption by the Dgraph.

--net-timeout Specifies the maximum amount of time (in seconds) the Dgraph waits for the client to download data from queries across the network. The default value is 30 seconds.
--out Specifies a file to which the Dgraph's stdout/stderr will be remapped. If this flag is omitted, the Dgraph uses its default stdout/stderr file, dgraph.out.

This file must be different from the one specified by the HDFS Agent's --out flag.

This flag maps to the DGRAPH_OUT_FILE property in bdd.conf.

--pidfile Specifies the file the Dgraph's process ID (PID) will be written to. The default filename is dgraph.pid.
--host Specifies the name of the Dgraph's host server.

This flag maps to the DGRAPH_SERVERS property in bdd.conf.

--port Specifies the port used by the Dgraph's host server.

This flag maps to the DGRAPH_WS_PORT property in bdd.conf.

--leader Creates a read/write Dgraph leader for the index. This flag is used internally.
--read-only Sets the index files to read-only. This flag is for internal use only by Oracle Support and should not be used by system administrators of Big Data Discovery 1.0.

When this flag is set, the Dgraph can only perform read-only operations. Any operations that attempt to write to the index files are rejected and return an HTTP status code 403.

--search_char_limit Specifies the maximum number of characters that a text search term can contain. The default value is 132.
--search_max Specifies the maximum number of terms that a text search query can contain. The default value is 10.
--snip_cutoff Specifies the maximum number of words in an attribute that the Dgraph will evaluate to identify a snippet. If a match is not found within the specified number of words, the Dgraph won't return a snippet, even if a match occurs later in the attribute value.

The default value is 500.

--snip_disable Globally disables snippeting.
--sslcafile
Note: This flag is not used in Oracle Big Data Discovery 1.0.
Specifies the path to the SSL Certificate Authority file that the Dgraph will use to authenticate SSL communications with other components.
--sslcertfile
Note: This flag is not used in Oracle Big Data Discovery 1.0.
Specifies the path of the SSL certificate file that the Dgraph will present to clients for SSL communications.
--stat-brel
Note: This flag is deprecated and not used in Oracle Big Data Discovery 1.0.
Creates dynamic record attributes that indicate the relevance rank assigned to full-text search result records.
--syslog Directs all output to syslog.
--threads Specifies the number of threads the Dgraph will use to process queries and execute internal maintenance tasks. The value you provide must be a positive integer (2 or greater).

The recommended number of threads for machines running only the Dgraph is the number of CPU cores the machine has. For machines co-hosting the Dgraph with other Big Data Discovery components, the recommended number of threads is the number of CPU cores the machine has minus two.

This flag maps to the DGRAPH_THREADS property in bdd.conf.

--validate_data Validates that all indexed data loads and then exits.
--version Prints version information and then exits. The version information includes the Oracle Big Data Discovery version number and the internal Dgraph identifier.
--wildcard_max Specifies the maximum number of terms that can match a wildcard term in a wildcard query that contains punctuation, such as ab*c.def*. The default is 100.