Class PartialResultSet (3.13.0)

public sealed class PartialResultSet : IMessage<PartialResultSet>, IEquatable<PartialResultSet>, IDeepCloneable<PartialResultSet>, IBufferMessage, IMessage

Partial results from a streaming read or SQL query. Streaming reads and SQL queries better tolerate large result sets, large rows, and large values, but are a little trickier to consume.

Inheritance

Object > PartialResultSet

Implements

IMessage<PartialResultSet>, IEquatable<PartialResultSet>, IDeepCloneable<PartialResultSet>, IBufferMessage, IMessage

Inherited Members

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ToString()

Namespace

Google.Cloud.Spanner.V1

Assembly

Google.Cloud.Spanner.V1.dll

Constructors

PartialResultSet()

public PartialResultSet()

PartialResultSet(PartialResultSet)

public PartialResultSet(PartialResultSet other)

Parameter
Name	Description
`other`	`PartialResultSet`

Properties

ChunkedValue

public bool ChunkedValue { get; set; }

If true, then the final value in [values][google.spanner.v1.PartialResultSet.values] is chunked, and must be combined with more values from subsequent PartialResultSets to obtain a complete field value.

Property Value
Type	Description
`Boolean`

Metadata

public ResultSetMetadata Metadata { get; set; }

Metadata about the result set, such as row type information. Only present in the first response.

Property Value
Type	Description
`ResultSetMetadata`

ResumeToken

public ByteString ResumeToken { get; set; }

Streaming calls might be interrupted for a variety of reasons, such as TCP connection loss. If this occurs, the stream of results can be resumed by re-sending the original request and including resume_token. Note that executing any other transaction in the same session invalidates the token.

Property Value
Type	Description
`ByteString`

Stats

public ResultSetStats Stats { get; set; }

Query plan and execution statistics for the statement that produced this streaming result set. These can be requested by setting [ExecuteSqlRequest.query_mode][google.spanner.v1.ExecuteSqlRequest.query_mode] and are sent only once with the last response in the stream. This field will also be present in the last response for DML statements.

Property Value
Type	Description
`ResultSetStats`

Values

public RepeatedField<Value> Values { get; }

A streamed result set consists of a stream of values, which might be split into many PartialResultSet messages to accommodate large rows and/or large values. Every N complete values defines a row, where N is equal to the number of entries in [metadata.row_type.fields][google.spanner.v1.StructType.fields].

Most values are encoded based on type as described [here][google.spanner.v1.TypeCode].

It is possible that the last value in values is "chunked", meaning that the rest of the value is sent in subsequent PartialResultSet(s). This is denoted by the [chunked_value][google.spanner.v1.PartialResultSet.chunked_value] field. Two or more chunked values can be merged to form a complete value as follows:

bool/number/null: cannot be chunked
string: concatenate the strings
list: concatenate the lists. If the last element in a list is a string, list, or object, merge it with the first element in the next list by applying these rules recursively.
object: concatenate the (field name, field value) pairs. If a field name is duplicated, then apply these rules recursively to merge the field values.

Some examples of merging:

Strings are concatenated.

"foo", "bar" => "foobar"

Lists of non-strings are concatenated.

[2, 3], [4] => [2, 3, 4]

Lists are concatenated, but the last and first elements are merged

because they are strings.

["a", "b"], ["c", "d"] => ["a", "bc", "d"]

Lists are concatenated, but the last and first elements are merged

because they are lists. Recursively, the last and first elements

of the inner lists are merged because they are strings.

["a", ["b", "c"]], [["d"], "e"] => ["a", ["b", "cd"], "e"]

Non-overlapping object fields are combined.

{"a": "1"}, {"b": "2"} => {"a": "1", "b": 2"}

Overlapping object fields are merged.

{"a": "1"}, {"a": "2"} => {"a": "12"}

Examples of merging objects containing lists of strings.

{"a": ["1"]}, {"a": ["2"]} => {"a": ["12"]}

For a more complete example, suppose a streaming SQL query is yielding a result set whose rows contain a single string field. The following PartialResultSets might be yielded:

{ "metadata": { ... } "values": ["Hello", "W"] "chunked_value": true "resume_token": "Af65..." } { "values": ["orl"] "chunked_value": true "resume_token": "Bqp2..." } { "values": ["d"] "resume_token": "Zx1B..." }

This sequence of PartialResultSets encodes two rows, one containing the field value "Hello", and a second containing the field value "World" = "W" + "orl" + "d".

Property Value
Type	Description
`RepeatedField<Value>`