Fix compression issues (lz4 deadlock + unknown conversions handling)

LZ4  в конструкторе пытается считать свое сигнатуру. Поэтому загрузку надо начинать до вызова конструктора иначе наступает deadlock

1 files changed, 5 insertions, 4 deletions

diff --git a/ydb/library/yql/providers/s3/actors/yql_s3_read_actor.cpp b/ydb/library/yql/providers/s3/actors/yql_s3_read_actor.cpp
index 795dbdc7b7..3a021f1ec9 100644
--- a/ydb/library/yql/providers/s3/actors/yql_s3_read_actor.cpp
+++ b/ydb/library/yql/providers/s3/actors/yql_s3_read_actor.cpp
@@ -1270,14 +1270,15 @@ public:
         std::unique_ptr<NDB::ReadBuffer> decompressorBuffer;
         NDB::ReadBuffer* buffer = coroBuffer.get();
 
+        // lz4 decompressor reads signature in ctor, w/o actual data it will be deadlocked
+        DownloadStart(RetryStuff, GetActorSystem(), SelfActorId, ParentActorId, PathIndex, HttpInflightSize);
+
         if (ReadSpec->Compression) {
             decompressorBuffer = MakeDecompressor(*buffer, ReadSpec->Compression);
-            YQL_ENSURE(buffer, "Unsupported " << ReadSpec->Compression << " compression.");
+            YQL_ENSURE(decompressorBuffer, "Unsupported " << ReadSpec->Compression << " compression.");
             buffer = decompressorBuffer.get();
         }
 
-        DownloadStart(RetryStuff, GetActorSystem(), SelfActorId, ParentActorId, PathIndex, HttpInflightSize);
-
         auto stream = std::make_unique<NDB::InputStreamFromInputFormat>(
             NDB::FormatFactory::instance().getInputFormat(
                 ReadSpec->Format, *buffer, NDB::Block(ReadSpec->CHColumns), nullptr, ReadActorFactoryCfg.RowsInBatch, ReadSpec->Settings
@@ -1303,7 +1304,7 @@ public:
 
         if (ReadSpec->Compression) {
             decompressorBuffer = MakeDecompressor(*buffer, ReadSpec->Compression);
-            YQL_ENSURE(buffer, "Unsupported " << ReadSpec->Compression << " compression.");
+            YQL_ENSURE(decompressorBuffer, "Unsupported " << ReadSpec->Compression << " compression.");
             buffer = decompressorBuffer.get();
         }