DStream::haKeyedBuffer

DStream::haKeyedBuffer(name, keyColumn, raftGroup, cacheLimit, [retentionMinutes=1440])

name is a string representing the name of the Orca stream table. You can provide either the fully qualified name (FQN), such as "trading.orca_table.factors", or just the table name, like "factors". If only the name is given, the system will automatically complete it using the current catalog.

keyColumn A string scalar or vector specifying the primary key column(s).

raftGroup is an integer greater than 1 indicating Raft group ID.

cacheLimit is an integer representing the maximum number of rows of the high-availability stream table to be kept in memory. If cacheLimit>1000, it is automatically adjusted to 1000.

retentionMinutes (optional) is an integer indicating for how long (in terms of minutes) a log file larger than 1GB will be kept after last update. The default value is 1440, which means the log file only keeps data in the past 24 hours.

Creates a high-availability keyed stream table to store intermediate results in stream processing.

For more information on table persistence, refer to the haStreamTable documentation.

Return value: A DStream object.

if (!existsCatalog("orca")) {
	createCatalog("orca")
}
go
use catalog orca

g = createStreamGraph("indicators")

g.source("trade", 1:0, `time`symbol`price`volume, [DATETIME,SYMBOL,DOUBLE,LONG])
    .timeSeriesEngine(windowSize=60, step=60, metrics=[<first(price) as open>, <max(price) as high>, <min(price) as low>, <last(price) as close>, <sum(volume) as volume>], timeColumn=`time, keyColumn=`symbol)
    .haKeyedBuffer(name="ha_keyedTable", keyColumn=`symbol, raftGroup=3, cacheLimit=5000)