Greenplum Streaming Server(GPSS)自定义客户端开发

1. GPSS服务定义

将以下内容复制到gpss.proto文件中，如下：

syntax = "proto3";
import "google/protobuf/empty.proto";
import "google/protobuf/struct.proto";
import "google/protobuf/timestamp.proto";

package api;

option java_multiple_files = true;

// Connect service Request message
message ConnectRequest {
  string Host = 1;      // Host address of Greenplum master; must be accessible from gpss server system
  int32 Port = 2;       // Greenplum master port
  string Username = 3;  // User or role name that gpss uses to access Greenplum 
  string Password = 4;  // User password
  string DB = 5;        // Database name
  bool UseSSL = 6;      // Use SSL or not; ignored, use the gpss config file to config SSL
}

// Connect service Response message
message Session {
  string ID = 1;  // Id of client connection to gpss
}

// Operation mode
enum Operation {
  Insert = 0;  // Insert all data into table; behavior of duplicate key or data depends upon the constraints of the target table.
  Merge = 1;   // Insert and Update
  Update = 2;  // Update the value of "UpdateColumns" if "MatchColumns" match
  Read = 3;    // Not supported
}

// Required parameters of the Insert operation
message InsertOption {
  repeated string InsertColumns = 1;    // Names of the target table columns the insert operation should update; used in 'INSERT INTO', useful for partial loading
  bool TruncateTable = 2;               // Truncate table before loading?
  int64 ErrorLimitCount = 4;            // Error limit count; used by external table
  int32 ErrorLimitPercentage = 5;       // Error limit percentage; used by external table
}

// Required parameters of the Update operation
message UpdateOption {
  repeated string MatchColumns = 1;     // Names of the target table columns to compare when determining to update or not
  repeated string UpdateColumns = 2;    // Names of the target table columns to update if MatchColumns match
  string Condition = 3;                 // Optional additional match condition; SQL syntax and used after the 'WHERE' clause
  int64 ErrorLimitCount = 4;            // Error limit count; used by external table
  int32 ErrorLimitPercentage = 5;       // Error limit percentage; used by external table
}

// Required parameters of the Merge operation
// Merge operation creates a session-level temp table in StagingSchema
message MergeOption {
  repeated string InsertColumns = 1;
  repeated string MatchColumns = 2;
  repeated string UpdateColumns = 3;
  string Condition = 4;
  int64 ErrorLimitCount = 5;
  int32 ErrorLimitPercentage = 6;
}

// Open service Request message
message OpenRequest {
  Session Session = 1;      // Session ID returned by Connect
  string SchemaName = 2;    // Name of the Greenplum Database schema
  string TableName = 3;     // Name of the Greenplum Database table
  string PreSQL = 4;        // SQL to execute before gpss loads the data
  string PostSQL = 5;       // SQL to execute after gpss loads the data
  int32 Timeout = 6;        // Time to wait before aborting the operation (seconds); not supported
  string Encoding = 7;      // Encoding of text data; not supported
  string StagingSchema = 8; // Schema in which gpss creates external and temp tables; default is to create these tables in the same schema as the target table

  oneof Option {            // Identify the type of write operation to perform
    InsertOption InsertOption = 100;
    UpdateOption UpdateOption = 101;
    MergeOption MergeOption = 102;
  }
}

message DBValue {
  oneof DBType {
    int32 Int32Value = 1;
    int64 Int64Value = 2;
    float Float32Value = 5;
    double Float64Value = 6;
    string StringValue = 7;  // Includes types whose values are presented as string but are not a real string type in Greenplum; for example: macaddr, time with time zone, box, etc.
    bytes BytesValue = 8;
    google.protobuf.Timestamp TimeStampValue = 10;  // Time without timezone
    google.protobuf.N