diff --git a/dbms/src/Common/ShellCommand.cpp b/dbms/src/Common/ShellCommand.cpp
index a4c16ee5c48..00010799aee 100644
--- a/dbms/src/Common/ShellCommand.cpp
+++ b/dbms/src/Common/ShellCommand.cpp
@@ -66,8 +66,8 @@ namespace
     enum class ReturnCodes : int
     {
         CANNOT_DUP_STDIN    = 42,   /// The value is not important, but it is chosen so that it's rare to conflict with the program return code.
-        CANNOT_DUP_STDOUT     = 43,
-        CANNOT_DUP_STDERR     = 44,
+        CANNOT_DUP_STDOUT   = 43,
+        CANNOT_DUP_STDERR   = 44,
         CANNOT_EXEC         = 45,
     };
 }
@@ -76,6 +76,11 @@ namespace
 namespace DB
 {
 
+ShellCommand::~ShellCommand()
+{
+    if (!wait_called)
+        tryWait();
+}
 
 std::unique_ptr<ShellCommand> ShellCommand::executeImpl(const char * filename, char * const argv[], bool pipe_stdin_only)
 {
@@ -176,6 +181,8 @@ std::unique_ptr<ShellCommand> ShellCommand::executeDirect(const std::string & pa
 
 int ShellCommand::tryWait()
 {
+    wait_called = true;
+
     int status = 0;
     if (-1 == waitpid(pid, &status, 0))
         throwFromErrno("Cannot waitpid", ErrorCodes::CANNOT_WAITPID);
diff --git a/dbms/src/Common/ShellCommand.h b/dbms/src/Common/ShellCommand.h
index a558216fcbf..8df7de1de35 100644
--- a/dbms/src/Common/ShellCommand.h
+++ b/dbms/src/Common/ShellCommand.h
@@ -27,6 +27,7 @@ class ShellCommand
 {
 private:
     pid_t pid;
+    bool wait_called = false;
 
     ShellCommand(pid_t pid, int in_fd, int out_fd, int err_fd)
         : pid(pid), in(in_fd), out(out_fd), err(err_fd) {};
@@ -38,6 +39,8 @@ public:
     ReadBufferFromFile out;
     ReadBufferFromFile err;
 
+    ~ShellCommand();
+
     /// Run the command using /bin/sh -c
     static std::unique_ptr<ShellCommand> execute(const std::string & command, bool pipe_stdin_only = false);
 
diff --git a/dbms/src/Common/tests/shell_command_test.cpp b/dbms/src/Common/tests/shell_command_test.cpp
index 564567373c8..81fadfd4a51 100644
--- a/dbms/src/Common/tests/shell_command_test.cpp
+++ b/dbms/src/Common/tests/shell_command_test.cpp
@@ -5,6 +5,8 @@
 #include <IO/WriteBufferFromFileDescriptor.h>
 #include <IO/ReadBufferFromString.h>
 
+#include <chrono>
+#include <thread>
 
 using namespace DB;
 
@@ -43,6 +45,15 @@ try
 
         command->wait();
     }
+
+    // <defunct> hunting:
+    for (int i = 0; i < 1000; ++i) {
+        auto command = ShellCommand::execute("echo " + std::to_string(i));
+        //command->wait(); // now automatic
+    }
+
+    // std::cerr << "inspect me: ps auxwwf" << "\n";
+    // std::this_thread::sleep_for(std::chrono::seconds(100));
 }
 catch (...)
 {