Golang

Pinot Client for Golang

Pinot also provides a native go client to query database directly from go application.

Installation

Please follow this Pinot Quickstart link to install and start Pinot batch QuickStart locally.

bin/quick-start-batch.sh

Check out Client library Github Repo

git clone [e-mail]:startreedata/pinot-client-go.git
cd pinot-client-go

Build and run the example application to query from Pinot Batch Quickstart

go build ./examples/batch-quickstart
./batch-quickstart

Usage

Create a Pinot Connection

Pinot client could be initialized through:

1. Zookeeper Path.

pinotClient := pinot.NewFromZookeeper([]string{"localhost:2123"}, "", "QuickStartCluster")

2. A list of broker addresses.

pinotClient := pinot.NewFromBrokerList([]string{"localhost:8000"})

3. ClientConfig

pinotClient := pinot.NewWithConfig(&pinot.ClientConfig{
	ZkConfig: &pinot.ZookeeperConfig{
		ZookeeperPath:     zkPath,
		PathPrefix:        strings.Join([]string{zkPathPrefix, pinotCluster}, "/"),
		SessionTimeoutSec: defaultZkSessionTimeoutSec,
	},
    ExtraHTTPHeader: map[string]string{
        "extra-header":"value",
    },
})

Query Pinot

Please see this example for your reference.

Code snippet:

pinotClient, err := pinot.NewFromZookeeper([]string{"localhost:2123"}, "", "QuickStartCluster")
if err != nil {
    log.Error(err)
}
brokerResp, err := pinotClient.ExecuteSQL("baseballStats", "select count(*) as cnt, sum(homeRuns) as sum_homeRuns from baseballStats group by teamID limit 10")
if err != nil {
    log.Error(err)
}
log.Infof("Query Stats: response time - %d ms, scanned docs - %d, total docs - %d", brokerResp.TimeUsedMs, brokerResp.NumDocsScanned, brokerResp.TotalDocs)

Response Format

Query Response is defined as the struct of following:

type BrokerResponse struct {
	AggregationResults          []*AggregationResult `json:"aggregationResults,omitempty"`
	SelectionResults            *SelectionResults    `json:"SelectionResults,omitempty"`
	ResultTable                 *ResultTable         `json:"resultTable,omitempty"`
	Exceptions                  []Exception          `json:"exceptions"`
	TraceInfo                   map[string]string    `json:"traceInfo,omitempty"`
	NumServersQueried           int                  `json:"numServersQueried"`
	NumServersResponded         int                  `json:"numServersResponded"`
	NumSegmentsQueried          int                  `json:"numSegmentsQueried"`
	NumSegmentsProcessed        int                  `json:"numSegmentsProcessed"`
	NumSegmentsMatched          int                  `json:"numSegmentsMatched"`
	NumConsumingSegmentsQueried int                  `json:"numConsumingSegmentsQueried"`
	NumDocsScanned              int64                `json:"numDocsScanned"`
	NumEntriesScannedInFilter   int64                `json:"numEntriesScannedInFilter"`
	NumEntriesScannedPostFilter int64                `json:"numEntriesScannedPostFilter"`
	NumGroupsLimitReached       bool                 `json:"numGroupsLimitReached"`
	TotalDocs                   int64                `json:"totalDocs"`
	TimeUsedMs                  int                  `json:"timeUsedMs"`
	MinConsumingFreshnessTimeMs int64                `json:"minConsumingFreshnessTimeMs"`
}

Note that AggregationResults and SelectionResults are holders for PQL queries.

Meanwhile ResultTable is the holder for SQL queries. ResultTable is defined as:

// ResultTable is a ResultTable
type ResultTable struct {
	DataSchema RespSchema      `json:"dataSchema"`
	Rows       [][]interface{} `json:"rows"`
}

RespSchema is defined as:

// RespSchema is response schema
type RespSchema struct {
	ColumnDataTypes []string `json:"columnDataTypes"`
	ColumnNames     []string `json:"columnNames"`
}

There are multiple functions defined for ResultTable, like:

func (r ResultTable) GetRowCount() int
func (r ResultTable) GetColumnCount() int
func (r ResultTable) GetColumnName(columnIndex int) string
func (r ResultTable) GetColumnDataType(columnIndex int) string
func (r ResultTable) Get(rowIndex int, columnIndex int) interface{}
func (r ResultTable) GetString(rowIndex int, columnIndex int) string
func (r ResultTable) GetInt(rowIndex int, columnIndex int) int
func (r ResultTable) GetLong(rowIndex int, columnIndex int) int64
func (r ResultTable) GetFloat(rowIndex int, columnIndex int) float32
func (r ResultTable) GetDouble(rowIndex int, columnIndex int) float64

Sample Usage is here

// Print Response Schema
for c := 0; c < brokerResp.ResultTable.GetColumnCount(); c++ {
  fmt.Printf("%s(%s)\t", brokerResp.ResultTable.GetColumnName(c), brokerResp.ResultTable.GetColumnDataType(c))
}
fmt.Println()

// Print Row Table
for r := 0; r < brokerResp.ResultTable.GetRowCount(); r++ {
  for c := 0; c < brokerResp.ResultTable.GetColumnCount(); c++ {
    fmt.Printf("%v\t", brokerResp.ResultTable.Get(r, c))
  }
  fmt.Println()
}