MDEV-20939: Race condition between mysqldump import and InnoDB persistent

statistics calculation

 Analysis: When --replace or --insert-ignore is not given, dumping of
mysql.innodb_index_stats and mysql.innodb_table_stats will result into race
condition.
Fix: Check if these options are present with --system=stats (because dumping
under --system=stats is safe). Otherwise, dump only structure, ignoring data
because innodb will recalculate data anyway.

1 files changed, 14 insertions, 0 deletions

diff --git a/client/mysqldump.c b/client/mysqldump.c
index 2eaec829867..ecca380777f 100644
--- a/client/mysqldump.c
+++ b/client/mysqldump.c
@@ -1052,6 +1052,20 @@ static int get_options(int *argc, char ***argv)
   if ((ho_error= handle_options(argc, argv, my_long_options, get_one_option)))
     return(ho_error);
 
+  /*
+    Dumping under --system=stats with --replace or --inser-ignore is safe and will not
+    retult into race condition. Otherwise dump only structure and ignore data by default
+    while dumping.
+  */
+  if (!(opt_system & OPT_SYSTEM_STATS) && !(opt_ignore || opt_replace_into))
+  {
+    if (my_hash_insert(&ignore_data,
+                       (uchar*) my_strdup("mysql.innodb_index_stats", MYF(MY_WME))) ||
+        my_hash_insert(&ignore_data,
+                       (uchar*) my_strdup("mysql.innodb_table_stats", MYF(MY_WME))))
+      return(EX_EOM);
+  }
+
   if (opt_system & OPT_SYSTEM_ALL)
       opt_system|= ~0;