// Copyright 2024 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

syntax = "proto3";

package google.bigtable.v2;

import "google/api/field_behavior.proto";
import "google/bigtable/v2/types.proto";
import "google/protobuf/timestamp.proto";
import "google/type/date.proto";

option csharp_namespace = "Google.Cloud.Bigtable.V2";
option go_package = "cloud.google.com/go/bigtable/apiv2/bigtablepb;bigtablepb";
option java_multiple_files = true;
option java_outer_classname = "DataProto";
option java_package = "com.google.bigtable.v2";
option php_namespace = "Google\\Cloud\\Bigtable\\V2";
option ruby_package = "Google::Cloud::Bigtable::V2";

// Specifies the complete (requested) contents of a single row of a table.
// Rows which exceed 256MiB in size cannot be read in full.
message Row {
  // The unique key which identifies this row within its table. This is the same
  // key that's used to identify the row in, for example, a MutateRowRequest.
  // May contain any non-empty byte string up to 4KiB in length.
  bytes key = 1;

  // May be empty, but only if the entire row is empty.
  // The mutual ordering of column families is not specified.
  repeated Family families = 2;
}

// Specifies (some of) the contents of a single row/column family intersection
// of a table.
message Family {
  // The unique key which identifies this family within its row. This is the
  // same key that's used to identify the family in, for example, a RowFilter
  // which sets its "family_name_regex_filter" field.
  // Must match `[-_.a-zA-Z0-9]+`, except that AggregatingRowProcessors may
  // produce cells in a sentinel family with an empty name.
  // Must be no greater than 64 characters in length.
  string name = 1;

  // Must not be empty. Sorted in order of increasing "qualifier".
  repeated Column columns = 2;
}

// Specifies (some of) the contents of a single row/column intersection of a
// table.
message Column {
  // The unique key which identifies this column within its family. This is the
  // same key that's used to identify the column in, for example, a RowFilter
  // which sets its `column_qualifier_regex_filter` field.
  // May contain any byte string, including the empty string, up to 16kiB in
  // length.
  bytes qualifier = 1;

  // Must not be empty. Sorted in order of decreasing "timestamp_micros".
  repeated Cell cells = 2;
}

// Specifies (some of) the contents of a single row/column/timestamp of a table.
message Cell {
  // The cell's stored timestamp, which also uniquely identifies it within
  // its column.
  // Values are always expressed in microseconds, but individual tables may set
  // a coarser granularity to further restrict the allowed values. For
  // example, a table which specifies millisecond granularity will only allow
  // values of `timestamp_micros` which are multiples of 1000.
  int64 timestamp_micros = 1;

  // The value stored in the cell.
  // May contain any byte string, including the empty string, up to 100MiB in
  // length.
  bytes value = 2;

  // Labels applied to the cell by a [RowFilter][google.bigtable.v2.RowFilter].
  repeated string labels = 3;
}

// `Value` represents a dynamically typed value.
// The typed fields in `Value` are used as a transport encoding for the actual
// value (which may be of a more complex type). See the documentation of the
// `Type` message for more details.
message Value {
  // The verified `Type` of this `Value`, if it cannot be inferred.
  //
  // Read results will never specify the encoding for `type` since the value
  // will already have been decoded by the server. Furthermore, the `type` will
  // be omitted entirely if it can be inferred from a previous response. The
  // exact semantics for inferring `type` will vary, and are therefore
  // documented separately for each read method.
  //
  // When using composite types (Struct, Array, Map) only the outermost `Value`
  // will specify the `type`. This top-level `type` will define the types for
  // any nested `Struct' fields, `Array` elements, or `Map` key/value pairs.
  // If a nested `Value` provides a `type` on write, the request will be
  // rejected with INVALID_ARGUMENT.
  Type type = 7;

  // Options for transporting values within the protobuf type system. A given
  // `kind` may support more than one `type` and vice versa. On write, this is
  // roughly analogous to a GoogleSQL literal.
  //
  // The value is `NULL` if none of the fields in `kind` is set. If `type` is
  // also omitted on write, we will infer it based on the schema.
  oneof kind {
    // Represents a raw byte sequence with no type information.
    // The `type` field must be omitted.
    bytes raw_value = 8;

    // Represents a raw cell timestamp with no type information.
    // The `type` field must be omitted.
    int64 raw_timestamp_micros = 9;

    // Represents a typed value transported as a byte sequence.
    bytes bytes_value = 2;

    // Represents a typed value transported as a string.
    string string_value = 3;

    // Represents a typed value transported as an integer.
    int64 int_value = 6;

    // Represents a typed value transported as a boolean.
    bool bool_value = 10;

    // Represents a typed value transported as a floating point number.
    double float_value = 11;

    // Represents a typed value transported as a timestamp.
    google.protobuf.Timestamp timestamp_value = 12;

    // Represents a typed value transported as a date.
    google.type.Date date_value = 13;

    // Represents a typed value transported as a sequence of values.
    // To differentiate between `Struct`, `Array`, and `Map`, the outermost
    // `Value` must provide an explicit `type` on write. This `type` will
    // apply recursively to the nested `Struct` fields, `Array` elements,
    // or `Map` key/value pairs, which *must not* supply their own `type`.
    ArrayValue array_value = 4;
  }
}

// `ArrayValue` is an ordered list of `Value`.
message ArrayValue {
  // The ordered elements in the array.
  repeated Value values = 1;
}

// Specifies a contiguous range of rows.
message RowRange {
  // The row key at which to start the range.
  // If neither field is set, interpreted as the empty string, inclusive.
  oneof start_key {
    // Used when giving an inclusive lower bound for the range.
    bytes start_key_closed = 1;

    // Used when giving an exclusive lower bound for the range.
    bytes start_key_open = 2;
  }

  // The row key at which to end the range.
  // If neither field is set, interpreted as the infinite row key, exclusive.
  oneof end_key {
    // Used when giving an exclusive upper bound for the range.
    bytes end_key_open = 3;

    // Used when giving an inclusive upper bound for the range.
    bytes end_key_closed = 4;
  }
}

// Specifies a non-contiguous set of rows.
message RowSet {
  // Single rows included in the set.
  repeated bytes row_keys = 1;

  // Contiguous row ranges included in the set.
  repeated RowRange row_ranges = 2;
}

// Specifies a contiguous range of columns within a single column family.
// The range spans from <column_family>:<start_qualifier> to
// <column_family>:<end_qualifier>, where both bounds can be either
// inclusive or exclusive.
message ColumnRange {
  // The name of the column family within which this range falls.
  string family_name = 1;

  // The column qualifier at which to start the range (within `column_family`).
  // If neither field is set, interpreted as the empty string, inclusive.
  oneof start_qualifier {
    // Used when giving an inclusive lower bound for the range.
    bytes start_qualifier_closed = 2;

    // Used when giving an exclusive lower bound for the range.
    bytes start_qualifier_open = 3;
  }

  // The column qualifier at which to end the range (within `column_family`).
  // If neither field is set, interpreted as the infinite string, exclusive.
  oneof end_qualifier {
    // Used when giving an inclusive upper bound for the range.
    bytes end_qualifier_closed = 4;

    // Used when giving an exclusive upper bound for the range.
    bytes end_qualifier_open = 5;
  }
}

// Specified a contiguous range of microsecond timestamps.
message TimestampRange {
  // Inclusive lower bound. If left empty, interpreted as 0.
  int64 start_timestamp_micros = 1;

  // Exclusive upper bound. If left empty, interpreted as infinity.
  int64 end_timestamp_micros = 2;
}

// Specifies a contiguous range of raw byte values.
message ValueRange {
  // The value at which to start the range.
  // If neither field is set, interpreted as the empty string, inclusive.
  oneof start_value {
    // Used when giving an inclusive lower bound for the range.
    bytes start_value_closed = 1;

    // Used when giving an exclusive lower bound for the range.
    bytes start_value_open = 2;
  }

  // The value at which to end the range.
  // If neither field is set, interpreted as the infinite string, exclusive.
  oneof end_value {
    // Used when giving an inclusive upper bound for the range.
    bytes end_value_closed = 3;

    // Used when giving an exclusive upper bound for the range.
    bytes end_value_open = 4;
  }
}

// Takes a row as input and produces an alternate view of the row based on
// specified rules. For example, a RowFilter might trim down a row to include
// just the cells from columns matching a given regular expression, or might
// return all the cells of a row but not their values. More complicated filters
// can be composed out of these components to express requests such as, "within
// every column of a particular family, give just the two most recent cells
// which are older than timestamp X."
//
// There are two broad categories of RowFilters (true filters and transformers),
// as well as two ways to compose simple filters into more complex ones
// (chains and interleaves). They work as follows:
//
// * True filters alter the input row by excluding some of its cells wholesale
// from the output row. An example of a true filter is the `value_regex_filter`,
// which excludes cells whose values don't match the specified pattern. All
// regex true filters use RE2 syntax (https://github.com/google/re2/wiki/Syntax)
// in raw byte mode (RE2::Latin1), and are evaluated as full matches. An
// important point to keep in mind is that `RE2(.)` is equivalent by default to
// `RE2([^\n])`, meaning that it does not match newlines. When attempting to
// match an arbitrary byte, you should therefore use the escape sequence `\C`,
// which may need to be further escaped as `\\C` in your client language.
//
// * Transformers alter the input row by changing the values of some of its
// cells in the output, without excluding them completely. Currently, the only
// supported transformer is the `strip_value_transformer`, which replaces every
// cell's value with the empty string.
//
// * Chains and interleaves are described in more detail in the
// RowFilter.Chain and RowFilter.Interleave documentation.
//
// The total serialized size of a RowFilter message must not
// exceed 20480 bytes, and RowFilters may not be nested within each other
// (in Chains or Interleaves) to a depth of more than 20.
message RowFilter {
  // A RowFilter which sends rows through several RowFilters in sequence.
  message Chain {
    // The elements of "filters" are chained together to process the input row:
    // in row -> f(0) -> intermediate row -> f(1) -> ... -> f(N) -> out row
    // The full chain is executed atomically.
    repeated RowFilter filters = 1;
  }

  // A RowFilter which sends each row to each of several component
  // RowFilters and interleaves the results.
  message Interleave {
    // The elements of "filters" all process a copy of the input row, and the
    // results are pooled, sorted, and combined into a single output row.
    // If multiple cells are produced with the same column and timestamp,
    // they will all appear in the output row in an unspecified mutual order.
    // Consider the following example, with three filters:
    //
    //                                  input row
    //                                      |
    //            -----------------------------------------------------
    //            |                         |                         |
    //           f(0)                      f(1)                      f(2)
    //            |                         |                         |
    //     1: foo,bar,10,x             foo,bar,10,z              far,bar,7,a
    //     2: foo,blah,11,z            far,blah,5,x              far,blah,5,x
    //            |                         |                         |
    //            -----------------------------------------------------
    //                                      |
    //     1:                      foo,bar,10,z   // could have switched with #2
    //     2:                      foo,bar,10,x   // could have switched with #1
    //     3:                      foo,blah,11,z
    //     4:                      far,bar,7,a
    //     5:                      far,blah,5,x   // identical to #6
    //     6:                      far,blah,5,x   // identical to #5
    //
    // All interleaved filters are executed atomically.
    repeated RowFilter filters = 1;
  }

  // A RowFilter which evaluates one of two possible RowFilters, depending on
  // whether or not a predicate RowFilter outputs any cells from the input row.
  //
  // IMPORTANT NOTE: The predicate filter does not execute atomically with the
  // true and false filters, which may lead to inconsistent or unexpected
  // results. Additionally, Condition filters have poor performance, especially
  // when filters are set for the false condition.
  message Condition {
    // If `predicate_filter` outputs any cells, then `true_filter` will be
    // evaluated on the input row. Otherwise, `false_filter` will be evaluated.
    RowFilter predicate_filter = 1;

    // The filter to apply to the input row if `predicate_filter` returns any
    // results. If not provided, no results will be returned in the true case.
    RowFilter true_filter = 2;

    // The filter to apply to the input row if `predicate_filter` does not
    // return any results. If not provided, no results will be returned in the
    // false case.
    RowFilter false_filter = 3;
  }

  // Which of the possible RowFilter types to apply. If none are set, this
  // RowFilter returns all cells in the input row.
  oneof filter {
    // Applies several RowFilters to the data in sequence, progressively
    // narrowing the results.
    Chain chain = 1;

    // Applies several RowFilters to the data in parallel and combines the
    // results.
    Interleave interleave = 2;

    // Applies one of two possible RowFilters to the data based on the output of
    // a predicate RowFilter.
    Condition condition = 3;

    // ADVANCED USE ONLY.
    // Hook for introspection into the RowFilter. Outputs all cells directly to
    // the output of the read rather than to any parent filter. Consider the
    // following example:
    //
    //     Chain(
    //       FamilyRegex("A"),
    //       Interleave(
    //         All(),
    //         Chain(Label("foo"), Sink())
    //       ),
    //       QualifierRegex("B")
    //     )
    //
    //                         A,A,1,w
    //                         A,B,2,x
    //                         B,B,4,z
    //                            |
    //                     FamilyRegex("A")
    //                            |
    //                         A,A,1,w
    //                         A,B,2,x
    //                            |
    //               +------------+-------------+
    //               |                          |
    //             All()                    Label(foo)
    //               |                          |
    //            A,A,1,w              A,A,1,w,labels:[foo]
    //            A,B,2,x              A,B,2,x,labels:[foo]
    //               |                          |
    //               |                        Sink() --------------+
    //               |                          |                  |
    //               +------------+      x------+          A,A,1,w,labels:[foo]
    //                            |                        A,B,2,x,labels:[foo]
    //                         A,A,1,w                             |
    //                         A,B,2,x                             |
    //                            |                                |
    //                    QualifierRegex("B")                      |
    //                            |                                |
    //                         A,B,2,x                             |
    //                            |                                |
    //                            +--------------------------------+
    //                            |
    //                         A,A,1,w,labels:[foo]
    //                         A,B,2,x,labels:[foo]  // could be switched
    //                         A,B,2,x               // could be switched
    //
    // Despite being excluded by the qualifier filter, a copy of every cell
    // that reaches the sink is present in the final result.
    //
    // As with an [Interleave][google.bigtable.v2.RowFilter.Interleave],
    // duplicate cells are possible, and appear in an unspecified mutual order.
    // In this case we have a duplicate with column "A:B" and timestamp 2,
    // because one copy passed through the all filter while the other was
    // passed through the label and sink. Note that one copy has label "foo",
    // while the other does not.
    //
    // Cannot be used within the `predicate_filter`, `true_filter`, or
    // `false_filter` of a [Condition][google.bigtable.v2.RowFilter.Condition].
    bool sink = 16;

    // Matches all cells, regardless of input. Functionally equivalent to
    // leaving `filter` unset, but included for completeness.
    bool pass_all_filter = 17;

    // Does not match any cells, regardless of input. Useful for temporarily
    // disabling just part of a filter.
    bool block_all_filter = 18;

    // Matches only cells from rows whose keys satisfy the given RE2 regex. In
    // other words, passes through the entire row when the key matches, and
    // otherwise produces an empty row.
    // Note that, since row keys can contain arbitrary bytes, the `\C` escape
    // sequence must be used if a true wildcard is desired. The `.` character
    // will not match the new line character `\n`, which may be present in a
    // binary key.
    bytes row_key_regex_filter = 4;

    // Matches all cells from a row with probability p, and matches no cells
    // from the row with probability 1-p.
    double row_sample_filter = 14;

    // Matches only cells from columns whose families satisfy the given RE2
    // regex. For technical reasons, the regex must not contain the `:`
    // character, even if it is not being used as a literal.
    // Note that, since column families cannot contain the new line character
    // `\n`, it is sufficient to use `.` as a full wildcard when matching
    // column family names.
    string family_name_regex_filter = 5;

    // Matches only cells from columns whose qualifiers satisfy the given RE2
    // regex.
    // Note that, since column qualifiers can contain arbitrary bytes, the `\C`
    // escape sequence must be used if a true wildcard is desired. The `.`
    // character will not match the new line character `\n`, which may be
    // present in a binary qualifier.
    bytes column_qualifier_regex_filter = 6;

    // Matches only cells from columns within the given range.
    ColumnRange column_range_filter = 7;

    // Matches only cells with timestamps within the given range.
    TimestampRange timestamp_range_filter = 8;

    // Matches only cells with values that satisfy the given regular expression.
    // Note that, since cell values can contain arbitrary bytes, the `\C` escape
    // sequence must be used if a true wildcard is desired. The `.` character
    // will not match the new line character `\n`, which may be present in a
    // binary value.
    bytes value_regex_filter = 9;

    // Matches only cells with values that fall within the given range.
    ValueRange value_range_filter = 15;

    // Skips the first N cells of each row, matching all subsequent cells.
    // If duplicate cells are present, as is possible when using an Interleave,
    // each copy of the cell is counted separately.
    int32 cells_per_row_offset_filter = 10;

    // Matches only the first N cells of each row.
    // If duplicate cells are present, as is possible when using an Interleave,
    // each copy of the cell is counted separately.
    int32 cells_per_row_limit_filter = 11;

    // Matches only the most recent N cells within each column. For example,
    // if N=2, this filter would match column `foo:bar` at timestamps 10 and 9,
    // skip all earlier cells in `foo:bar`, and then begin matching again in
    // column `foo:bar2`.
    // If duplicate cells are present, as is possible when using an Interleave,
    // each copy of the cell is counted separately.
    int32 cells_per_column_limit_filter = 12;

    // Replaces each cell's value with the empty string.
    bool strip_value_transformer = 13;

    // Applies the given label to all cells in the output row. This allows
    // the client to determine which results were produced from which part of
    // the filter.
    //
    // Values must be at most 15 characters in length, and match the RE2
    // pattern `[a-z0-9\\-]+`
    //
    // Due to a technical limitation, it is not currently possible to apply
    // multiple labels to a cell. As a result, a Chain may have no more than
    // one sub-filter which contains a `apply_label_transformer`. It is okay for
    // an Interleave to contain multiple `apply_label_transformers`, as they
    // will be applied to separate copies of the input. This may be relaxed in
    // the future.
    string apply_label_transformer = 19;
  }
}

// Specifies a particular change to be made to the contents of a row.
message Mutation {
  // A Mutation which sets the value of the specified cell.
  message SetCell {
    // The name of the family into which new data should be written.
    // Must match `[-_.a-zA-Z0-9]+`
    string family_name = 1;

    // The qualifier of the column into which new data should be written.
    // Can be any byte string, including the empty string.
    bytes column_qualifier = 2;

    // The timestamp of the cell into which new data should be written.
    // Use -1 for current Bigtable server time.
    // Otherwise, the client should set this value itself, noting that the
    // default value is a timestamp of zero if the field is left unspecified.
    // Values must match the granularity of the table (e.g. micros, millis).
    int64 timestamp_micros = 3;

    // The value to be written into the specified cell.
    bytes value = 4;
  }

  // A Mutation which incrementally updates a cell in an `Aggregate` family.
  message AddToCell {
    // The name of the `Aggregate` family into which new data should be added.
    // This must be a family with a `value_type` of `Aggregate`.
    // Format: `[-_.a-zA-Z0-9]+`
    string family_name = 1;

    // The qualifier of the column into which new data should be added. This
    // must be a `raw_value`.
    Value column_qualifier = 2;

    // The timestamp of the cell to which new data should be added. This must
    // be a `raw_timestamp_micros` that matches the table's `granularity`.
    Value timestamp = 3;

    // The input value to be accumulated into the specified cell. This must be
    // compatible with the family's `value_type.input_type`.
    Value input = 4;
  }

  // A Mutation which merges accumulated state into a cell in an `Aggregate`
  // family.
  message MergeToCell {
    // The name of the `Aggregate` family into which new data should be added.
    // This must be a family with a `value_type` of `Aggregate`.
    // Format: `[-_.a-zA-Z0-9]+`
    string family_name = 1;

    // The qualifier of the column into which new data should be added. This
    // must be a `raw_value`.
    Value column_qualifier = 2;

    // The timestamp of the cell to which new data should be added. This must
    // be a `raw_timestamp_micros` that matches the table's `granularity`.
    Value timestamp = 3;

    // The input value to be merged into the specified cell. This must be
    // compatible with the family's `value_type.state_type`. Merging `NULL` is
    // allowed, but has no effect.
    Value input = 4;
  }

  // A Mutation which deletes cells from the specified column, optionally
  // restricting the deletions to a given timestamp range.
  message DeleteFromColumn {
    // The name of the family from which cells should be deleted.
    // Must match `[-_.a-zA-Z0-9]+`
    string family_name = 1;

    // The qualifier of the column from which cells should be deleted.
    // Can be any byte string, including the empty string.
    bytes column_qualifier = 2;

    // The range of timestamps within which cells should be deleted.
    TimestampRange time_range = 3;
  }

  // A Mutation which deletes all cells from the specified column family.
  message DeleteFromFamily {
    // The name of the family from which cells should be deleted.
    // Must match `[-_.a-zA-Z0-9]+`
    string family_name = 1;
  }

  // A Mutation which deletes all cells from the containing row.
  message DeleteFromRow {}

  // Which of the possible Mutation types to apply.
  oneof mutation {
    // Set a cell's value.
    SetCell set_cell = 1;

    // Incrementally updates an `Aggregate` cell.
    AddToCell add_to_cell = 5;

    // Merges accumulated state to an `Aggregate` cell.
    MergeToCell merge_to_cell = 6;

    // Deletes cells from a column.
    DeleteFromColumn delete_from_column = 2;

    // Deletes cells from a column family.
    DeleteFromFamily delete_from_family = 3;

    // Deletes cells from the entire row.
    DeleteFromRow delete_from_row = 4;
  }
}

// Specifies an atomic read/modify/write operation on the latest value of the
// specified column.
message ReadModifyWriteRule {
  // The name of the family to which the read/modify/write should be applied.
  // Must match `[-_.a-zA-Z0-9]+`
  string family_name = 1;

  // The qualifier of the column to which the read/modify/write should be
  // applied.
  // Can be any byte string, including the empty string.
  bytes column_qualifier = 2;

  // The rule used to determine the column's new latest value from its current
  // latest value.
  oneof rule {
    // Rule specifying that `append_value` be appended to the existing value.
    // If the targeted cell is unset, it will be treated as containing the
    // empty string.
    bytes append_value = 3;

    // Rule specifying that `increment_amount` be added to the existing value.
    // If the targeted cell is unset, it will be treated as containing a zero.
    // Otherwise, the targeted cell must contain an 8-byte value (interpreted
    // as a 64-bit big-endian signed integer), or the entire request will fail.
    int64 increment_amount = 4;
  }
}

// NOTE: This API is intended to be used by Apache Beam BigtableIO.
// A partition of a change stream.
message StreamPartition {
  // The row range covered by this partition and is specified by
  // [`start_key_closed`, `end_key_open`).
  RowRange row_range = 1;
}

// NOTE: This API is intended to be used by Apache Beam BigtableIO.
// The information required to continue reading the data from multiple
// `StreamPartitions` from where a previous read left off.
message StreamContinuationTokens {
  // List of continuation tokens.
  repeated StreamContinuationToken tokens = 1;
}

// NOTE: This API is intended to be used by Apache Beam BigtableIO.
// The information required to continue reading the data from a
// `StreamPartition` from where a previous read left off.
message StreamContinuationToken {
  // The partition that this token applies to.
  StreamPartition partition = 1;

  // An encoded position in the stream to restart reading from.
  string token = 2;
}

// Protocol buffers format descriptor, as described by Messages ProtoSchema and
// ProtoRows
message ProtoFormat {}

// Describes a column in a Bigtable Query Language result set.
message ColumnMetadata {
  // The name of the column.
  string name = 1;

  // The type of the column.
  Type type = 2;
}

// ResultSet schema in proto format
message ProtoSchema {
  // The columns in the result set.
  repeated ColumnMetadata columns = 1;
}

// Describes the structure of a Bigtable result set.
message ResultSetMetadata {
  // The schema of the ResultSet, contains ordered list of column names
  // with types
  oneof schema {
    // Schema in proto format
    ProtoSchema proto_schema = 1;
  }
}

// Rows represented in proto format.
//
// This should be constructed by concatenating the `batch_data` from each
// of the relevant `ProtoRowsBatch` messages and parsing the result as a
// `ProtoRows` message.
message ProtoRows {
  // A proto rows message consists of a list of values. Every N complete values
  // defines a row, where N is equal to the  number of entries in the
  // `metadata.proto_schema.columns` value received in the first response.
  repeated Value values = 2;
}

// Batch of serialized ProtoRows.
message ProtoRowsBatch {
  // Merge partial results by concatenating these bytes, then parsing the
  // overall value as a `ProtoRows` message.
  bytes batch_data = 1;
}

// A partial result set from the streaming query API.
// CBT client will buffer partial_rows from result_sets until it gets a
// resumption_token.
message PartialResultSet {
  // Partial Rows in one of the supported formats. It may require many
  // PartialResultSets to stream a batch of rows that can decoded on the client.
  // The client should buffer partial_rows until it gets a `resume_token`,
  // at which point the batch is complete and can be decoded and yielded to the
  // user. Each sub-message documents the appropriate way to combine results.
  oneof partial_rows {
    // Partial rows in serialized ProtoRows format.
    ProtoRowsBatch proto_rows_batch = 3;
  }

  // An opaque token sent by the server to allow query resumption and signal
  // the client to accumulate `partial_rows` since the last non-empty
  // `resume_token`. On resumption, the resumed query will return the remaining
  // rows for this query.
  //
  // If there is a batch in progress, a non-empty `resume_token`
  // means that that the batch of `partial_rows` will be complete after merging
  // the `partial_rows` from this response. The client must only yield
  // completed batches to the application, and must ensure that any future
  // retries send the latest token to avoid returning duplicate data.
  //
  // The server may set 'resume_token' without a 'partial_rows'. If there is a
  // batch in progress the client should yield it.
  //
  // 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
  // `partial_rows`, then return OK.
  bytes resume_token = 5;

  // Estimated size of a new batch. The server will always set this when
  // returning the first `partial_rows` of a batch, and will not set it at any
  // other time.
  //
  // The client can use this estimate to allocate an initial buffer for the
  // batched 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.
  int32 estimated_batch_size = 4;
}