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[];
/=>
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