Class PartialResultSet
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.
Implements
Inherited Members
Namespace: Google.Apis.Spanner.v1.Data
Assembly: Google.Apis.Spanner.v1.dll
Syntax
public class PartialResultSet : IDirectResponseSchema
Properties
ChunkedValue
If true, then the final value in values is chunked, and must be combined with more values from subsequent
PartialResultSet
s to obtain a complete field value.
Declaration
[JsonProperty("chunkedValue")]
public virtual bool? ChunkedValue { get; set; }
Property Value
Type | Description |
---|---|
bool? |
ETag
The ETag of the item.
Declaration
public virtual string ETag { get; set; }
Property Value
Type | Description |
---|---|
string |
Metadata
Metadata about the result set, such as row type information. Only present in the first response.
Declaration
[JsonProperty("metadata")]
public virtual ResultSetMetadata Metadata { get; set; }
Property Value
Type | Description |
---|---|
ResultSetMetadata |
PrecommitToken
Optional. A precommit token will be included if the read-write transaction is on a multiplexed session. The precommit token with the highest sequence number from this transaction attempt should be passed to the Commit request for this transaction.
Declaration
[JsonProperty("precommitToken")]
public virtual MultiplexedSessionPrecommitToken PrecommitToken { get; set; }
Property Value
Type | Description |
---|---|
MultiplexedSessionPrecommitToken |
ResumeToken
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.
Declaration
[JsonProperty("resumeToken")]
public virtual string ResumeToken { get; set; }
Property Value
Type | Description |
---|---|
string |
Stats
Query plan and execution statistics for the statement that produced this streaming result set. These can be requested by setting 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.
Declaration
[JsonProperty("stats")]
public virtual ResultSetStats Stats { get; set; }
Property Value
Type | Description |
---|---|
ResultSetStats |
Values
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. Most values are encoded based on type as
described here. 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 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 PartialResultSet
s might be yielded: { "metadata": { ... } "values": ["Hello", "W"]
"chunked_value": true "resume_token": "Af65..." } { "values": ["orl"] "chunked_value": true } { "values":
["d"] "resume_token": "Zx1B..." } This sequence of PartialResultSet
s encodes two rows, one containing the
field value "Hello"
, and a second containing the field value "World" = "W" + "orl" + "d"
. Not all
PartialResultSet
s contain a resume_token
. Execution can only be resumed from a previously yielded
resume_token
. For the above sequence of PartialResultSet
s, resuming the query with "resume_token": "Af65..."
will yield results from the PartialResultSet
with value ["orl"]
.
Declaration
[JsonProperty("values")]
public virtual IList<object> Values { get; set; }
Property Value
Type | Description |
---|---|
IList<object> |