From 044b146c555409059e2d2e9fe02ac7ed201c13b4 Mon Sep 17 00:00:00 2001
From: Igor Gaponenko <gapon@slac.stanford.edu>
Date: Fri, 21 Jul 2023 02:01:41 +0000
Subject: [PATCH] Fixed a candidate bug in the MySQL query cancellation

Also, added a logging statement on failures to do so.
---
 src/mysql/MySqlConnection.cc | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/mysql/MySqlConnection.cc b/src/mysql/MySqlConnection.cc
index 48a88858af..f9532242ac 100644
--- a/src/mysql/MySqlConnection.cc
+++ b/src/mysql/MySqlConnection.cc
@@ -155,7 +155,7 @@ bool MySqlConnection::queryUnbuffered(std::string const& query) {
 int MySqlConnection::cancel() {
     std::lock_guard<std::mutex> lock(_interruptMutex);
     int rc;
-    if (!_isExecuting || _interrupted) {
+    if (_interrupted) {
         // Should we log this?
         return -1;  // No further action needed.
     }
@@ -172,6 +172,9 @@ int MySqlConnection::cancel() {
     rc = mysql_real_query(killMysql, killSql.c_str(), killSql.size());
     mysql_close(killMysql);
     if (rc) {
+        LOGS(_log, LOG_LVL_WARN,
+             "failed to kill MySQL thread: " << threadId << ", error: " << std::string(mysql_error(killMysql))
+                                             << ", errno: " << std::to_string(mysql_errno(killMysql)));
         return 2;
     }
     return 0;