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Analytics using the Go SDK

Parallel data management for complex queries over many records, using a familiar N1QL-like syntax.

For complex and long-running queries, involving large ad hoc join, set, aggregation, and grouping operations, Couchbase Data Platform introduces the Couchbase Analytics Service. After familiarising yourself with our introductory primer, in particular creating a dataset and linking it to a bucket to shadow the operational data, try Couchbase Analytics using the Go SDK.

Availability

The analytics service is available in Couchbase Data Platform 6.0 and later (developer preview in 5.5). While earlier Go SDK versions provide some support, we strongly recommend to use at least version 1.5.0, which provides a committed and stable interface for it.

Usage: Performing a Request

Intentionally, the API for analytics is very similar to the query service one:

func (b *Bucket) ExecuteAnalyticsQuery(q *AnalyticsQuery, params interface{}) (AnalyticsResults, error)

To perform a query, you need to create an AnalyticsQuery. If parameters are used, they can either be positional or named. Here is one example of each:

query := gocb.NewAnalyticsQuery("select airportname, country from airports where country = 'France'")
res, err := bucket.ExecuteAnalyticsQuery(q, nil)
query := gocb.NewAnalyticsQuery("select airportname, country from airports where country = ?")
res, err := bucket.ExecuteAnalyticsQuery(q, []interface{}{"France"})
query := gocb.NewAnalyticsQuery("select airportname, country from airports where country = $country")
params := make(map[string]interface{})
params["country"] = "France"
res, err := bucket.ExecuteAnalyticsQuery(q, params)

Additional options are available at query time which can be passed in through the AnalyticsQuery object:

Table 1. Analytics Params Reference
Name Builder Default Description

Client Context ID

ContextId(string)

Random UUID

Sets a context ID that is returned back as part of the result.

Server Side Timeout

ServerSideTimeout(time.Duration)

Analytics timeout set on the client (75s)

Customizes the timeout sent to the server. Usually does not have to be set because the client sets it based on the timeout on the operation.

Pretty

Pretty(bool)

false

If the returned result should be prettified JSON.

Priority

Priority(bool)

false

If this request should have priority over others.

Raw Param

RawParam(string, interface{})

none

Allows to send arbitrary params to the analytics service which are not part of the builder API.

These params must be sent as part of the query:

query := gocb.NewAnalyticsQuery("select airportname, country from airports where country = 'France'").Priority(true).ServerSideTimeout(1 * time.Second)

The timeout is always propagated to the server, so when a timeout happens on the client side the server can also stop processing the request and save resources.

Usage: Handling the Response

Once the request has been executed, results are sent back to the client and it will return an AnalyticsResults:

result, err = bucket.ExecuteAnalyticsQuery(query, params)

The result contains all kinds of actual data and metadata which might or might not be set, depending on the query response. The resulting rows can be accessed through Next(valuePtr interface{}) bool, NextBytes() []byte or One(valuePtr interface{}) error. Here is an example:

result, err = bucket.ExecuteAnalyticsQuery(
    "SELECT airportname, country FROM airports WHERE country = 'France' LIMIT 5",
    nil)
if (err != nil) {
    panic(err)
}

var row interface{}
for result.Next(&row) {
    fmt.Printf("%+v", row)
}

err := result.Close()
if (err != nil) {
    panic(err)
}

Always be sure to check Close() for any errors.

Additional metrics can be accessed through the Metrics() function, such as ElapsedTime or the ResultCount.