From 156d64637987f0413dc9e8a568a9d9fe7bfd2297 Mon Sep 17 00:00:00 2001
From: Alek5andr-Kotov <akotov@ydb.tech>
Date: Fri, 10 Oct 2025 21:37:26 +0300
Subject: [PATCH] Blob compaction stops after TEvGetWriteInfo (#26660)

---
 .../persqueue/pqtablet/partition/partition.cpp    |  7 +++++++
 ydb/core/persqueue/pqtablet/partition/partition.h |  5 +++++
 .../pqtablet/partition/partition_compaction.cpp   | 15 +++++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/ydb/core/persqueue/pqtablet/partition/partition.cpp b/ydb/core/persqueue/pqtablet/partition/partition.cpp
index 7d4844692f08..b14c23397a30 100644
--- a/ydb/core/persqueue/pqtablet/partition/partition.cpp
+++ b/ydb/core/persqueue/pqtablet/partition/partition.cpp
@@ -1472,6 +1472,13 @@ void TPartition::Handle(TEvPQ::TEvGetWriteInfoRequest::TPtr& ev, const TActorCon
                                      "Topic.Partition.GetWriteInfo",
                                      NWilson::EFlags::AUTO_END);
 
+    StopCompaction = true;
+    if (CompactionInProgress) {
+        LOG_D("Event TEvPQ::TEvGetWriteInfoRequest will be processed later");
+        PendingGetWriteInfoRequest.reset(ev->Release().Release());
+        return;
+    }
+
     ProcessPendingEvent(ev, ctx);
 }
 
diff --git a/ydb/core/persqueue/pqtablet/partition/partition.h b/ydb/core/persqueue/pqtablet/partition/partition.h
index 9d3bc0bac5a2..f278b2c1fb82 100644
--- a/ydb/core/persqueue/pqtablet/partition/partition.h
+++ b/ydb/core/persqueue/pqtablet/partition/partition.h
@@ -1166,6 +1166,11 @@ class TPartition : public TBaseActor<TPartition> {
     bool WasTheLastBlobBig = true;
 
     void DumpKeysForBlobsCompaction() const;
+
+    void TryProcessGetWriteInfoRequest(const TActorContext& ctx);
+
+    std::unique_ptr<TEvPQ::TEvGetWriteInfoRequest> PendingGetWriteInfoRequest;
+    bool StopCompaction = false;
 };
 
 inline ui64 TPartition::GetStartOffset() const {
diff --git a/ydb/core/persqueue/pqtablet/partition/partition_compaction.cpp b/ydb/core/persqueue/pqtablet/partition/partition_compaction.cpp
index 58136a8b4507..45675caeccb4 100644
--- a/ydb/core/persqueue/pqtablet/partition/partition_compaction.cpp
+++ b/ydb/core/persqueue/pqtablet/partition/partition_compaction.cpp
@@ -163,6 +163,11 @@ void TPartition::DumpKeysForBlobsCompaction() const
 
 void TPartition::TryRunCompaction()
 {
+    if (StopCompaction) {
+        LOG_D("Blobs compaction is stopped");
+        return;
+    }
+
     if (CompactionInProgress) {
         LOG_D("Blobs compaction in progress");
         return;
@@ -499,10 +504,20 @@ void TPartition::BlobsForCompactionWereWrite()
     KeysForCompaction.clear();
     CompactionBlobsCount = 0;
 
+    TryProcessGetWriteInfoRequest(ctx);
+
     ProcessTxsAndUserActs(ctx); // Now you can delete unnecessary keys.
     TryRunCompaction();
 }
 
+void TPartition::TryProcessGetWriteInfoRequest(const TActorContext& ctx)
+{
+    if (PendingGetWriteInfoRequest) {
+        ProcessPendingEvent(std::move(PendingGetWriteInfoRequest), ctx);
+        PendingGetWriteInfoRequest = nullptr;
+    }
+}
+
 void TPartition::EndProcessWritesForCompaction(TEvKeyValue::TEvRequest* request, const TInstant blobCreationUnixTime, const TActorContext& ctx)
 {
     if (CompactionBlobEncoder.HeadCleared) {