From 63a7d3439e9d2fc0c44880cc9fc53e6d13ed9fd0 Mon Sep 17 00:00:00 2001
From: robot-clickhouse <robot-clickhouse@users.noreply.github.com>
Date: Mon, 4 Dec 2023 14:04:59 +0000
Subject: [PATCH] Backport #57352 to 23.8: MergeTree mutations reuse source
 part index granularity

---
 .../MergeTree/MergedBlockOutputStream.cpp     |  5 +++--
 .../MergeTree/MergedBlockOutputStream.h       |  3 ++-
 src/Storages/MergeTree/MutateTask.cpp         | 19 ++++++++++++++++++-
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/Storages/MergeTree/MergedBlockOutputStream.cpp b/src/Storages/MergeTree/MergedBlockOutputStream.cpp
index bfd9e92b4eb6..7afa8701a485 100644
--- a/src/Storages/MergeTree/MergedBlockOutputStream.cpp
+++ b/src/Storages/MergeTree/MergedBlockOutputStream.cpp
@@ -23,7 +23,8 @@ MergedBlockOutputStream::MergedBlockOutputStream(
     const MergeTreeTransactionPtr & txn,
     bool reset_columns_,
     bool blocks_are_granules_size,
-    const WriteSettings & write_settings_)
+    const WriteSettings & write_settings_,
+    const MergeTreeIndexGranularity & computed_index_granularity)
     : IMergedBlockOutputStream(data_part, metadata_snapshot_, columns_list_, reset_columns_)
     , columns_list(columns_list_)
     , default_codec(default_codec_)
@@ -47,7 +48,7 @@ MergedBlockOutputStream::MergedBlockOutputStream(
     data_part->version.setCreationTID(tid, nullptr);
     data_part->storeVersionMetadata();
 
-    writer = data_part->getWriter(columns_list, metadata_snapshot, skip_indices, default_codec, writer_settings, {});
+    writer = data_part->getWriter(columns_list, metadata_snapshot, skip_indices, default_codec, writer_settings, computed_index_granularity);
 }
 
 /// If data is pre-sorted.
diff --git a/src/Storages/MergeTree/MergedBlockOutputStream.h b/src/Storages/MergeTree/MergedBlockOutputStream.h
index 20e6de5a99b9..d8ce15fdc0c6 100644
--- a/src/Storages/MergeTree/MergedBlockOutputStream.h
+++ b/src/Storages/MergeTree/MergedBlockOutputStream.h
@@ -23,7 +23,8 @@ class MergedBlockOutputStream final : public IMergedBlockOutputStream
         const MergeTreeTransactionPtr & txn,
         bool reset_columns_ = false,
         bool blocks_are_granules_size = false,
-        const WriteSettings & write_settings = {});
+        const WriteSettings & write_settings = {},
+        const MergeTreeIndexGranularity & computed_index_granularity = {});
 
     Block getHeader() const { return metadata_snapshot->getSampleBlock(); }
 
diff --git a/src/Storages/MergeTree/MutateTask.cpp b/src/Storages/MergeTree/MutateTask.cpp
index 865c2a87240a..510a7e5e82be 100644
--- a/src/Storages/MergeTree/MutateTask.cpp
+++ b/src/Storages/MergeTree/MutateTask.cpp
@@ -1414,6 +1414,22 @@ class MutateAllPartColumnsTask : public IExecutableTask
 
         ctx->minmax_idx = std::make_shared<IMergeTreeDataPart::MinMaxIndex>();
 
+        MergeTreeIndexGranularity computed_granularity;
+        bool has_delete = false;
+
+        for (auto & command_for_interpreter : ctx->for_interpreter)
+        {
+            if (command_for_interpreter.type == MutationCommand::DELETE)
+            {
+                has_delete = true;
+                break;
+            }
+        }
+
+        /// Reuse source part granularity if mutation does not change number of rows
+        if (!has_delete && ctx->execute_ttl_type == ExecuteTTLType::NONE)
+            computed_granularity = ctx->source_part->index_granularity;
+
         ctx->out = std::make_shared<MergedBlockOutputStream>(
             ctx->new_data_part,
             ctx->metadata_snapshot,
@@ -1423,7 +1439,8 @@ class MutateAllPartColumnsTask : public IExecutableTask
             ctx->txn,
             /*reset_columns=*/ true,
             /*blocks_are_granules_size=*/ false,
-            ctx->context->getWriteSettings());
+            ctx->context->getWriteSettings(),
+            computed_granularity);
 
         ctx->mutating_pipeline = QueryPipelineBuilder::getPipeline(std::move(builder));
         ctx->mutating_pipeline.setProgressCallback(ctx->progress_callback);