add proto definitions

Author: polyzos

fluss-rpc/src/main/java/org/apache/fluss/rpc/protocol/ApiKeys.java

@@ -74,7 +74,9 @@ public enum ApiKeys {
     CONTROLLED_SHUTDOWN(1043, 0, 0, PRIVATE),
     ALTER_TABLE(1044, 0, 0, PUBLIC),
     DESCRIBE_CLUSTER_CONFIGS(1045, 0, 0, PUBLIC),
-    ALTER_CLUSTER_CONFIGS(1046, 0, 0, PUBLIC);
+    ALTER_CLUSTER_CONFIGS(1046, 0, 0, PUBLIC),
+    KV_SCAN(1046, 0, 0, PUBLIC),
+    KV_SCAN_HEARTBEAT(1046, 0, 0, PUBLIC);
 
     private static final Map<Integer, ApiKeys> ID_TO_TYPE =
             Arrays.stream(ApiKeys.values())

fluss-rpc/src/main/proto/FlussApi.proto

@@ -269,6 +269,94 @@ message LimitScanResponse{
   optional bytes records = 4;
 }
 
+message NewScanRequestPB {
+  // The tablet to scan.
+  optional int64 partition_id = 1;
+  required int32 bucket_id = 2;
+
+  // The maximum number of rows to scan with the new scanner.
+  //
+  // The scanner will automatically stop yielding results and close itself
+  // after reaching this number of result rows.
+  optional uint64 limit = 3;
+}
+
+// A scan request. Initially, it should specify a scan. Later on, you
+// can use the scanner id returned to fetch result batches with a different
+// scan request.
+//
+// The scanner will remain open if there are more results, and it's not
+// asked to be closed explicitly.
+//
+// Clients may choose to retry scan requests that fail to complete (due to, for
+// example, a timeout or network error).
+//
+// You can fetch the results and ask the scanner to be closed to save
+// a trip if you are not interested in remaining results.
+message ScanRequest {
+  // If continuing an existing scan, then you must set scanner_id.
+  // Otherwise, you must set 'new_scan_request'.
+  optional bytes scanner_id = 1;
+  optional NewScanRequestPB new_scan_request = 2;
+
+  // The sequence ID of this call. It ensures that tablet server receives
+  // scanner requests in the correct order and helps detect and prevent errors
+  // caused by out-of-order or repeated requests.
+  // The sequence ID should start at 0 with the request for a new scanner, and
+  // after each successful request, the client should increment it by 1. When
+  // retrying a request, the client should _not_ increment this value. If the server
+  // detects that the client missed a chunk of rows from the middle of a scan, it will
+  // respond with an error.
+  optional uint32 call_seq_id = 3;
+
+  // The maximum number of bytes to send in the response.
+  optional uint32 batch_size_bytes = 4;
+
+  // If set, the server will close the scanner after responding to
+  // this request, regardless of whether all rows have been delivered.
+  optional bool close_scanner = 5;
+
+  // Query id is used to trace the whole process of reading tablets.
+  optional bytes query_id = 6;
+}
+
+message ScanResponse {
+  // The error, if an error occurred with this request.
+  optional int32 error_code = 1;
+  optional string error_message = 2;
+
+  // When a scanner is created, returns the scanner ID which may be used
+  // to pull new rows from the scanner.
+  optional bytes scanner_id = 3;
+
+  // Set to true to indicate that there may be further results to be fetched
+  // from this scanner. If the scanner has no more results, then the scanner
+  // ID will become invalid and cannot continue to be used.
+  //
+  // Note that if a scan returns no results, then the initial response from
+  // the first RPC may return false in this flag, in which case there will
+  // be no scanner ID assigned.
+  optional bool has_more_results = 4;
+
+  // The block of returned rows.
+  //
+  // NOTE: the schema-related fields will not be present in this row block.
+  // The schema will match the schema requested by the client when it created
+  // the scanner.
+  optional bytes records = 5;
+}
+
+// A scanner keep-alive request.
+// Updates the scanner access time, increasing its time-to-live.
+message ScannerKeepAliveRequest {
+  required bytes scanner_id = 1;
+}
+
+message ScannerKeepAliveResponse {
+  // The error, if an error occurred with this request.
+  optional int32 error_code = 1;
+  optional string error_message = 2;
+}
 
 // notify bucket leader and isr request
 message NotifyLeaderAndIsrRequest {