add dummy statistics request and response

ydb/core/protos/statistics.proto

@@ -94,7 +94,10 @@ message TEvGetScanStatusResponse {
 message TEvStatisticsScanRequest {
     optional NKikimrDataEvents.TTableId TableId = 1;
     optional bytes StartKey = 2;
+    // list of columns to gather statistics from. Empty means asking for every column.
     repeated uint32 ColumnTags = 3;
+    // list of statistics types requested. Empty means asking for all available.
+    repeated uint32 Types = 4;
 }
 
 message TEvStatisticsScanResponse {

ydb/core/tx/columnshard/columnshard.h

@@ -4,6 +4,7 @@
 
 #include <ydb/core/tx/tx.h>
 #include <ydb/core/tx/message_seqno.h>
+#include <ydb/core/protos/statistics.pb.h>
 #include <ydb/core/protos/tx_columnshard.pb.h>
 #include <ydb/public/api/protos/ydb_status_codes.pb.h>
 #include <ydb/core/tx/data_events/write_data.h>
@@ -83,6 +84,9 @@ struct TEvColumnShard {
         EvApplyLinksModification,
         EvApplyLinksModificationFinished,
 
+        EvStatisticsScanRequest,
+        EvStatisticsScanResponse,
+
         EvEnd
     };
 
@@ -253,6 +257,20 @@ struct TEvColumnShard {
         }
     };
 
+    struct TEvStatisticsScanRequest
+        : public TEventPB<TEvStatisticsScanRequest,
+                          NKikimrStat::TEvStatisticsScanRequest,
+                          EvStatisticsScanRequest>
+    {
+    };
+
+    struct TEvStatisticsScanResponse
+        : public TEventPB<TEvStatisticsScanResponse,
+                          NKikimrStat::TEvStatisticsScanResponse,
+                          EvStatisticsScanResponse>
+    {
+    };
+
     using TEvScan = TEvDataShard::TEvKqpScan;
 
 };

ydb/core/tx/columnshard/columnshard__statistics_scan.cpp

@@ -0,0 +1,18 @@
+#include "columnshard.h"
+#include "columnshard_impl.h"
+
+#include <ydb/core/protos/kqp.pb.h>
+
+namespace NKikimr::NColumnShard {
+
+void TColumnShard::Handle(TEvColumnShard::TEvStatisticsScanRequest::TPtr& ev, const TActorContext& ctx) {
+    auto response = std::make_unique<TEvDataShard::TEvStatisticsScanResponse>();
+    auto& record = response->Record;
+    record.SetShardTabletId(TabletID());
+
+    record.SetStatus(NKikimrStat::TEvStatisticsScanResponse::SUCCESS);
+
+    ctx.Send(new IEventHandle(ev->Sender, TActorId(), response.release(), 0, ev->Cookie));
+}
+
+}

ydb/core/tx/columnshard/columnshard_impl.h

@@ -220,6 +220,8 @@ class TColumnShard
     void Handle(TEvPrivate::TEvTieringModified::TPtr& ev, const TActorContext&);
     void Handle(TEvPrivate::TEvNormalizerResult::TPtr& ev, const TActorContext&);
 
+    void Handle(TEvColumnShard::TEvStatisticsScanRequest::TPtr& ev, const TActorContext& ctx);
+
     void Handle(NActors::TEvents::TEvUndelivered::TPtr& ev, const TActorContext&);
 
     void Handle(NOlap::NBlobOperations::NEvents::TEvDeleteSharedBlobs::TPtr& ev, const TActorContext& ctx);
@@ -373,6 +375,8 @@ class TColumnShard
             HFunc(TEvPrivate::TEvGarbageCollectionFinished, Handle);
             HFunc(TEvPrivate::TEvTieringModified, Handle);
 
+            HFunc(TEvColumnShard::TEvStatisticsScanRequest, Handle);
+
             HFunc(NActors::TEvents::TEvUndelivered, Handle);
 
             HFunc(NOlap::NBlobOperations::NEvents::TEvDeleteSharedBlobs, Handle);

ydb/core/tx/columnshard/ya.make

@@ -11,6 +11,7 @@ SRCS(
     columnshard__propose_cancel.cpp
     columnshard__propose_transaction.cpp
     columnshard__scan.cpp
+    columnshard__statistics_scan.cpp
     columnshard__write.cpp
     columnshard__write_index.cpp
     columnshard.cpp