Add feature flag: enable olap compression (#8726)

Author: Vladislav Gogov

ydb/core/kqp/ut/common/kqp_ut_common.cpp

@@ -133,6 +133,7 @@ TKikimrRunner::TKikimrRunner(const TKikimrSettings& settings) {
     ServerSettings->SetUseRealThreads(settings.UseRealThreads);
     ServerSettings->SetEnableTablePgTypes(true);
     ServerSettings->SetEnablePgSyntax(true);
+    ServerSettings->SetEnableOlapCompression(true);
     ServerSettings->S3ActorsFactory = settings.S3ActorsFactory;
 
     if (settings.Storage) {

ydb/core/protos/feature_flags.proto

@@ -158,4 +158,5 @@ message TFeatureFlags {
     optional bool EnablePgSyntax = 139 [default = true];
     optional bool EnableTieringInColumnShard = 140 [default = false];
     optional bool EnableMetadataObjectsOnServerless = 141 [default = true];
+    optional bool EnableOlapCompression = 142 [default = false];
 }

ydb/core/testlib/basics/feature_flags.h

@@ -67,6 +67,7 @@ class TTestFeatureFlagsHolder {
     FEATURE_FLAG_SETTER(EnablePgSyntax)
     FEATURE_FLAG_SETTER(EnableTieringInColumnShard)
     FEATURE_FLAG_SETTER(EnableMetadataObjectsOnServerless)
+    FEATURE_FLAG_SETTER(EnableOlapCompression)
 
     #undef FEATURE_FLAG_SETTER
 };

ydb/core/tx/schemeshard/olap/operations/alter/common/update.h

@@ -19,6 +19,16 @@ class TColumnTableUpdate: public ISSEntityUpdate {
         return NKikimrTxColumnShard::ETransactionKind::TX_KIND_SCHEMA;
     }
     virtual TConclusionStatus DoInitializeImpl(const TUpdateInitializationContext& context) = 0;
+
+    bool IsAlterCompression(const TUpdateInitializationContext& context) const {
+        for (const auto& alterColumn : context.GetModification()->GetAlterColumnTable().GetAlterSchema().GetAlterColumns()) {
+            if (alterColumn.HasSerializer()) {
+                return true;
+            }
+        }
+        return false;
+    }
+
 protected:
     virtual TConclusionStatus DoStartImpl(const TUpdateStartContext& /*context*/) {
         return TConclusionStatus::Success();
@@ -27,6 +37,9 @@ class TColumnTableUpdate: public ISSEntityUpdate {
         return TConclusionStatus::Success();
     }
     virtual TConclusionStatus DoInitialize(const TUpdateInitializationContext& context) override final {
+        if (!AppData()->FeatureFlags.GetEnableOlapCompression() && IsAlterCompression(context)) {
+            return TConclusionStatus::Fail("Compression is disabled for OLAP tables");
+        }
         if (!context.GetModification()->HasAlterColumnTable() && !context.GetModification()->HasAlterTable()) {
             return TConclusionStatus::Fail("no update data");
         }

ydb/core/tx/schemeshard/olap/operations/alter_store.cpp

@@ -436,6 +436,18 @@ class TAlterOlapStore: public TSubOperation {
         }
     }
 
+    bool IsAlterCompression() const {
+        const auto& alter = Transaction.GetAlterColumnStore();
+        for (const auto& alterSchema : alter.GetAlterSchemaPresets()) {
+            for (const auto& alterColumn : alterSchema.GetAlterSchema().GetAlterColumns()) {
+                if (alterColumn.HasSerializer()) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
 public:
     using TSubOperation::TSubOperation;
 
@@ -460,6 +472,11 @@ class TAlterOlapStore: public TSubOperation {
             return result;
         }
 
+        if (!AppData()->FeatureFlags.GetEnableOlapCompression() && IsAlterCompression()) {
+            result->SetError(NKikimrScheme::StatusPreconditionFailed, "Compression is disabled for OLAP tables");
+            return result;
+        }
+
         TPath parentPath = TPath::Resolve(parentPathStr, context.SS);
         TPath path = parentPath.Dive(name);
         {