public sealed class PartialResultSet : IMessage<PartialResultSet>, IEquatable<PartialResultSet>, IDeepCloneable<PartialResultSet>, IBufferMessage, IMessage
Reference documentation and code samples for the Google Bigtable v2 API class PartialResultSet.
A partial result set from the streaming query API.
Cloud Bigtable clients buffer partial results received in this message until
a resume_token
is received.
The pseudocode below describes how to buffer and parse a stream of
PartialResultSet
messages.
Having:
- queue of row results waiting to be returned
queue
- extensible buffer of bytes
buffer
- a place to keep track of the most recent
resume_token
for each PartialResultSetp
received { if p.reset { ensurequeue
is empty ensurebuffer
is empty } if p.estimated_batch_size != 0 { (optional) ensurebuffer
is sized to at leastp.estimated_batch_size
} ifp.proto_rows_batch
is set { appendp.proto_rows_batch.bytes
tobuffer
} if p.batch_checksum is set andbuffer
is not empty { validate the checksum matches the contents ofbuffer
(see comments onbatch_checksum
) parsebuffer
asProtoRows
message, clearingbuffer
add parsed rows to end ofqueue
} if p.resume_token is set { release results inqueue
savep.resume_token
inresume_token
} }
Implements
IMessagePartialResultSet, IEquatablePartialResultSet, IDeepCloneablePartialResultSet, IBufferMessage, IMessageNamespace
Google.Cloud.Bigtable.V2Assembly
Google.Cloud.Bigtable.V2.dll
Constructors
PartialResultSet()
public PartialResultSet()
PartialResultSet(PartialResultSet)
public PartialResultSet(PartialResultSet other)
Parameter | |
---|---|
Name | Description |
other |
PartialResultSet |
Properties
BatchChecksum
public uint BatchChecksum { get; set; }
CRC32C checksum of concatenated partial_rows
data for the current batch.
When present, the buffered data from partial_rows
forms a complete
parseable message of the appropriate type.
The client should mark the end of a parseable message and prepare to
receive a new one starting from the next PartialResultSet
message.
Clients must verify the checksum of the serialized batch before yielding it
to the caller.
This does NOT mean the values can be yielded to the callers since a
resume_token
is required to safely do so.
If resume_token
is non-empty and any data has been received since the
last one, this field is guaranteed to be non-empty. In other words, clients
may assume that a batch will never cross a resume_token
boundary.
Property Value | |
---|---|
Type | Description |
uint |
EstimatedBatchSize
public int EstimatedBatchSize { get; set; }
Estimated size of the buffer required to hold the next batch of results.
This value will be sent with the first partial_rows
of a batch. That is,
on the first partial_rows
received in a stream, on the first message
after a batch_checksum
message, and any time reset
is true.
The client can use this estimate to allocate a buffer for the next batch of results. This helps minimize the number of allocations required, though the buffer size may still need to be increased if the estimate is too low.
Property Value | |
---|---|
Type | Description |
int |
HasBatchChecksum
public bool HasBatchChecksum { get; }
Gets whether the "batch_checksum" field is set
Property Value | |
---|---|
Type | Description |
bool |
PartialRowsCase
public PartialResultSet.PartialRowsOneofCase PartialRowsCase { get; }
Property Value | |
---|---|
Type | Description |
PartialResultSetPartialRowsOneofCase |
ProtoRowsBatch
public ProtoRowsBatch ProtoRowsBatch { get; set; }
Partial rows in serialized ProtoRows format.
Property Value | |
---|---|
Type | Description |
ProtoRowsBatch |
Reset
public bool Reset { get; set; }
If true
, any data buffered since the last non-empty resume_token
must
be discarded before the other parts of this message, if any, are handled.
Property Value | |
---|---|
Type | Description |
bool |
ResumeToken
public ByteString ResumeToken { get; set; }
An opaque token sent by the server to allow query resumption and signal
that the buffered values constructed from received partial_rows
can be
yielded to the caller. Clients can provide this token in a subsequent
request to resume the result stream from the current point.
When resume_token
is non-empty, the buffered values received from
partial_rows
since the last non-empty resume_token
can be yielded to
the callers, provided that the client keeps the value of resume_token
and
uses it on subsequent retries.
A resume_token
may be sent without information in partial_rows
to
checkpoint the progress of a sparse query. Any previous partial_rows
data
should still be yielded in this case, and the new resume_token
should be
saved for future retries as normal.
A resume_token
will only be sent on a boundary where there is either no
ongoing result batch, or batch_checksum
is also populated.
The server will also send a sentinel resume_token
when last batch of
partial_rows
is sent. If the client retries the ExecuteQueryRequest with
the sentinel resume_token
, the server will emit it again without any
data in partial_rows
, then return OK.
Property Value | |
---|---|
Type | Description |
ByteString |