Avoid mutex for direct IO

Author: dentiny

CMakeLists.txt

@@ -6,7 +6,8 @@ project(HTTPFsExtension)
 
 add_extension_definitions()
 
-include_directories(extension/httpfs/include ${DUCKDB_MODULE_BASE_DIR}/third_party/httplib)
+include_directories(extension/httpfs/include
+                    ${DUCKDB_MODULE_BASE_DIR}/third_party/httplib)
 
 build_static_extension(
   httpfs
@@ -38,16 +39,17 @@ endif()
 find_package(OpenSSL REQUIRED)
 include_directories(${OPENSSL_INCLUDE_DIR})
 if(EMSCRIPTEN)
-else()
-target_link_libraries(httpfs_loadable_extension duckdb_mbedtls
-                      ${OPENSSL_LIBRARIES})
-target_link_libraries(httpfs_extension duckdb_mbedtls ${OPENSSL_LIBRARIES})
 
-if(MINGW)
-  find_package(ZLIB)
-  target_link_libraries(httpfs_loadable_extension ZLIB::ZLIB -lcrypt32)
-  target_link_libraries(httpfs_extension ZLIB::ZLIB -lcrypt32)
-endif()
+else()
+  target_link_libraries(httpfs_loadable_extension duckdb_mbedtls
+                        ${OPENSSL_LIBRARIES})
+  target_link_libraries(httpfs_extension duckdb_mbedtls ${OPENSSL_LIBRARIES})
+
+  if(MINGW)
+    find_package(ZLIB)
+    target_link_libraries(httpfs_loadable_extension ZLIB::ZLIB -lcrypt32)
+    target_link_libraries(httpfs_extension ZLIB::ZLIB -lcrypt32)
+  endif()
 endif()
 
 install(

extension/httpfs/httpfs.cpp

@@ -515,7 +515,14 @@ void HTTPFileSystem::Read(FileHandle &handle, void *buffer, int64_t nr_bytes, id
 	if (skip_buffer && to_read > 0) {
 		GetRangeRequest(hfh, hfh.path, {}, location, (char *)buffer, to_read);
 
-		std::lock_guard<std::mutex> lck(hfh.mu);
+		// Update handle status within critical section for parallel access.
+		if (hfh.flags.RequireParallelAccess()) {
+			std::lock_guard<std::mutex> lck(hfh.mu);
+			hfh.buffer_available = 0;
+			hfh.buffer_idx = 0;
+			return;
+		}
+
 		hfh.buffer_available = 0;
 		hfh.buffer_idx = 0;
 		return;