Struct gcp_client::google::spanner::v1::PartialResultSet

pub struct PartialResultSet {
    pub metadata: Option<ResultSetMetadata>,
    pub values: Vec<Value>,
    pub chunked_value: bool,
    pub resume_token: Vec<u8>,
    pub stats: Option<ResultSetStats>,
}

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.

Fields

metadata: Option<ResultSetMetadata>

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

values: Vec<Value>

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:

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

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

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

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

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

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

{"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".

chunked_value: bool

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.

resume_token: Vec<u8>

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.

stats: Option<ResultSetStats>

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.

Trait Implementations

impl Clone for PartialResultSet

fn clone(&self) -> PartialResultSet

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PartialResultSet

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Default for PartialResultSet

fn default() -> PartialResultSet

Returns the "default value" for a type.

impl Message for PartialResultSet

fn encode_raw<B>(&self, buf: &mut B) where
    B: BufMut, 

fn merge_field<B>(
    &mut self,
    tag: u32,
    wire_type: WireType,
    buf: &mut B,
    ctx: DecodeContext
) -> Result<(), DecodeError> where
    B: Buf, 

fn encoded_len(&self) -> usize

Returns the encoded length of the message without a length delimiter.

fn clear(&mut self)

Clears the message, resetting all fields to their default.

fn encode<B>(&self, buf: &mut B) -> Result<(), EncodeError> where
    B: BufMut, 

Encodes the message to a buffer.

fn encode_length_delimited<B>(&self, buf: &mut B) -> Result<(), EncodeError> where
    B: BufMut, 

Encodes the message with a length-delimiter to a buffer.

fn decode<B>(buf: B) -> Result<Self, DecodeError> where
    B: Buf,
    Self: Default, 

Decodes an instance of the message from a buffer.

fn decode_length_delimited<B>(buf: B) -> Result<Self, DecodeError> where
    B: Buf,
    Self: Default, 

Decodes a length-delimited instance of the message from the buffer.

fn merge<B>(&mut self, buf: B) -> Result<(), DecodeError> where
    B: Buf, 

Decodes an instance of the message from a buffer, and merges it into self.

fn merge_length_delimited<B>(&mut self, buf: B) -> Result<(), DecodeError> where
    B: Buf, 

Decodes a length-delimited instance of the message from buffer, and merges it into self.

impl PartialEq<PartialResultSet> for PartialResultSet

fn eq(&self, other: &PartialResultSet) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &PartialResultSet) -> bool

This method tests for !=.

impl StructuralPartialEq for PartialResultSet