QueryIterator()

This operation creates an iterator for paginating through large query result sets.

func (c *Client) QueryIterator(ctx context.Context, option QueryIteratorOption, callOptions ...grpc.CallOption) (QueryIterator, error)

Request Syntax

option := milvusclient.NewQueryIteratorOption(collectionName).
    WithBatchSize(batchSize).
    WithPartitions(partitionNames).
    WithFilter(expr).
    WithOutputFields(fieldNames).
    WithConsistencyLevel(consistencyLevel).
    WithIteratorLimit(limit)

result, err := client.QueryIterator(ctx, option)

PARAMETERS:

• collectionName (string)

  The name of the target collection.

OPTION METHODS:

• WithBatchSize(batchSize int)

  Sets the number of entities to fetch per iteration batch.

• WithPartitions(partitionNames ...string)

  Limits the operation to the specified partitions.

• WithFilter(expr string)

  Applies a boolean filter expression to narrow results.

• WithOutputFields(fieldNames ...string)

  Specifies which fields to include in the returned results.

• WithConsistencyLevel(consistencyLevel [entity.ConsistencyLevel](../Collection/ConsistencyLevel.md))

  Sets the consistency level for the operation (Strong, Bounded, Session, or Eventually).

• WithIteratorLimit(limit int64)

  WithIteratorLimit sets the limit of entries to iterate if limit < 0, then it will be set to Unlimited

RETURN TYPE:

QueryIterator, error

RETURNS:

A QueryIterator for paginating through query results. Returns an error if the operation fails.

EXCEPTIONS:

• error

  Check err != nil for failure details.

Example

import (
    "context"
    "fmt"
    "io"

    "github.com/milvus-io/milvus/client/v2/milvusclient"
)

ctx, cancel := context.WithCancel(context.Background())
defer cancel()

milvusAddr := "127.0.0.1:19530"

cli, err := milvusclient.New(ctx, &milvusclient.ClientConfig{
    Address: milvusAddr,
})
if err != nil {
    // handle error
}

defer cli.Close(ctx)

iter, err := cli.QueryIterator(ctx, milvusclient.NewQueryIteratorOption("quick_setup").
    WithFilter("color like "red%"").
    WithOutputFields("id", "color"))
if err != nil {
    // handle error
}

for {
    resultSet, err := iter.Next(ctx)
    if err == io.EOF {
        break
    }
    if err != nil {
        // handle error
    }
    for i := 0; i < resultSet.Len(); i++ {
        fmt.Println(resultSet.IDs)
    }
}