Druid:how to add a numeric data to metric without aggregation function - aggregate

Question

The scenario is i want to setup a stock quote server and save the quote data into druid.
my requirement is to get the latest price of all the stock by a query.
But i notice that the query interface of druid such as time series only work on metrics filed ,not the dimension fields.
so i consider to make the price filed one of the metrics,but no need to aggregated.
how can i do it?
Any suggestions?
here is my tranquility config file.
{
"dataSources" : {
"stock-index-topic" : {
"spec" : {
"dataSchema" : {
"dataSource" : "stock-index-topic",
"parser" : {
"type" : "string",
"parseSpec" : {
"timestampSpec" : {
"column" : "timestamp",
"format" : "auto"
},
"dimensionsSpec" : {
"dimensions" : ["code","name","acronym","market","tradeVolume","totalValueTraded","preClosePx","openPrice","highPrice","lowPrice","latestPrice","closePx"],
"dimensionExclusions" : [
"timestamp",
"value"
]
},
"format" : "json"
}
},
"granularitySpec" : {
"type" : "uniform",
"segmentGranularity" : "HOUR",
"queryGranularity" : "SECOND",
},
"metricsSpec" : [
{
"name" : "firstPrice",
"type" : "doubleFirst",
"fieldName" : "tradePrice"
},{
"name" : "lastPrice",
"type" : "doubleLast",
"fieldName" : "tradePrice"
}, {
"name" : "minPrice",
"type" : "doubleMin",
"fieldName" : "tradePrice"
}, {
"name" : "maxPrice",
"type" : "doubleMax",
"fieldName" : "tradePrice"
}
]
},
"ioConfig" : {
"type" : "realtime"
},
"tuningConfig" : {
"type" : "realtime",
"maxRowsInMemory" : "100000",
"intermediatePersistPeriod" : "PT10M",
"windowPeriod" : "PT10M"
}
},
"properties" : {
"task.partitions" : "1",
"task.replicants" : "1",
"topicPattern" : "stock-index-topic"
}
}
},
"properties" : {
"zookeeper.connect" : "localhost:2181",
"druid.discovery.curator.path" : "/druid/discovery",
"druid.selectors.indexing.serviceName" : "druid/overlord",
"commit.periodMillis" : "15000",
"consumer.numThreads" : "2",
"kafka.zookeeper.connect" : "localhost:2181",
"kafka.group.id" : "tranquility-kafka"
}
}

Answer 1

I think you should make [latest_price] as new numeric dimension, it would be much better from performance and querying standpoint considering how druid works.
Metrics and meant to perform aggregation functions as core so won't be helpful in your use case.