DS_RDB

The RDB is a Real-Time Database that stores intra-day data that can be queried by the user. The RDB is an extension of the RTE functionality. At start-up it reads in all of the RTE code. As such the RDB has all of the parameters of the RTE. The RDB typically subscribes to data from the Tickerplant and stores this data for intra-day queries. At start up the RDB loads the TP log file if it is required depending on the logMsgFunct specified in the input parameters. The RDB also supports End-Of-Day write down to a Historical Database. Depending on the required uses of the RDB it can subscribe to filtered lists of tables and syms. It can be queried via any q process, an IDE in Control, Dashboards or Excel.

Parameters

The below table details the RDB template parameters.

name	type	default value	description
messagingServer	Configuration	DS_MESSAGING_SERVER	Messaging server
subscriptionChannel	Symbol		Messaging channel to subscribe to
subscriptionTablelist	Symbol[]		List of tables to subscribe to
subscriptionColumnList	Symbol[]		Column to subscribe to in each table for the subscriptionFilterList values
subscriptionFilterList	Symbol[]		List of symbols to subscribe to
publishChannel	Symbol		Messaging channel to publish on
publishTableList	Symbol[]		List of tables to publish on
logMsgFunct	Analytic	dxUpdInsertPub	Specifies which log replay function to use, run for each incoming replayed data segment.
postLogMsg	Analytic	dxEmptyFunction	Specifies task(s) to perform after the ticker replay function completes running.
bufferMsgFunct	Analytic	dxEmptyFunction	Specifies message buffer function to use.
postbufferMsg	Analytic	dxEmptyFunction	Specifies task(s) to perform after the message buffer updates have been processed.
initialStateFunct	Analytic	dxInitialDataState	Specifies the Analytic to be used to initialize the RDB process.
realTimeMsgFunct	Analytic	dxUpdInsertPub	Update function to be used by the RDB
logReplayFunct	Analytic	dxLogReplay	Specifies log replay function
eodFunct	Analytic	dxEODSaveAndDelete	End of day (EOD) actions
rollOverFunct	Analytic	dxRolloverMultiServer	Function called by DS_EOD
hdbProcess	Process Instance		Historical Database Process
gatewayQuery	Analytic	dxQuery_basic	Gateway Query utilised
monitoringInterval	Integer		Monitoring Interval
tableEodList	Configuration	DS_TABLES_EOD_LIST	EOD tables
subscriptionSource	Process Instance		List of processes that the RDB should subscribe to
consumerProcesses	Process Instance		List of consumer processes
consumerAlertSize	Integer		Number of bytes in output queue of a consumer process to trigger an alert
consumerDisconnectSize	Integer		Number of bytes in output queue of a consumer process to trigger a disconnect
endInterval	Analytic	dxEndIntervalTemplate	Function to call when TP sends endInterval trigger
intervalDelete	Analytic	dxRdbDeleteTables	Function to delete data from tables when dxRdbDelete is called

APIs

.ds.rdb.getHdbHandleByInst

Used to get the handle of a specific HDB.

Parameter(s):

Name	Type	Description
instance	symbol	HDB instance

Returns:

Type	Description
int	HDB handle

Example:

.ds.rdb.getHdbHandleByInst[`ds_hdb_fx_eval];
/=>
12i

.ds.rdb.getHdbHandleList

Returns a list of all the handles to hdbs available to the process.

Returns:

Type	Description
int[]	Handles available

Example:

.ds.rdb.getHdbHandleList[];
/=>
16 18i

.ds.rdb.getHdbHandle

Returns the handle of the hdb available to the rdb process.

Returns:

Type	Description
int	HDB handle available to rdb process

Example:

.ds.rdb.getHdbHandle[];
/=>
12i

.ds.rdb.hdbReconnInst

RDB is not restricted to a single HDB. Many HDB can be defined within the instance parameters. This method is used internally with a timer job - .ds.rdb.hdbReconn.

Timer job runs and checks handle of each of the defined HDB instances, passes instance name to hdbReconnByInst to get connection details and attempt a reconnect

Parameter(s):

Name	Type	Description
instance	symbol	HDB instance

Returns:

Type	Description
int	HDB handle

Example:

.ds.rdb.hdbReconnByInst[`ds_hdb_fx_eval2];
/=>
18i

.ds.rdb.reloadHDB

Wrapper for the RDB to call to reload its Primary HDB. Allows RDB to reload HDB under the deltacomponent user.

It creates a handle and runs a reload under the that handle.

Returns:

Type	Description
boolean	Successful or not

Example:

.ds.rdb.reloadHDB[];
/=>
1b