MDEV-10161: wsrep_sync_wait not enabled when set to 1 in config file

Since wsrep_sync_wait & wsrep_causal_reads variables are related,
they are always kept in sync whenever one of them changes.
Same is tried on server start, where wsrep_sync_wait get updated
based on wsrep_causal_reads' value. But, since wsrep_causal_reads
is OFF by default, wsrep_sync_wait's value gets modified and loses
its WSREP_SYNC_WAIT_BEFORE_READ bit.

Fixed by syncing wsrep_sync_wait & wsrep_causal_reads values
individually on server start in mysqld_get_one_option() based
on command line arguments used.

4 files changed, 17 insertions, 4 deletions

diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 6c8f79bf37a..a19ac8aa968 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -9266,6 +9266,16 @@ mysqld_get_one_option(int optid, const struct my_option *opt, char *argument)
 #endif
     break;
   }
+#ifdef WITH_WSREP
+  case OPT_WSREP_CAUSAL_READS:
+    wsrep_causal_reads_update(&global_system_variables);
+    break;
+  case OPT_WSREP_SYNC_WAIT:
+    global_system_variables.wsrep_causal_reads=
+      MY_TEST(global_system_variables.wsrep_sync_wait &
+              WSREP_SYNC_WAIT_BEFORE_READ);
+    break;
+#endif /* WITH_WSREP */
   }
   return 0;
 }
diff --git a/sql/mysqld.h b/sql/mysqld.h
index 594afac521d..8454f2410dc 100644
--- a/sql/mysqld.h
+++ b/sql/mysqld.h
@@ -636,6 +636,10 @@ enum options_mysqld
   OPT_SSL_KEY,
   OPT_THREAD_CONCURRENCY,
   OPT_WANT_CORE,
+#ifdef WITH_WSREP
+  OPT_WSREP_CAUSAL_READS,
+  OPT_WSREP_SYNC_WAIT,
+#endif /* WITH_WSREP */
   OPT_MYSQL_COMPATIBILITY,
   OPT_MYSQL_TO_BE_IMPLEMENTED,
   OPT_which_is_always_the_last
diff --git a/sql/sys_vars.cc b/sql/sys_vars.cc
index 29e167d4664..c733976452c 100644
--- a/sql/sys_vars.cc
+++ b/sql/sys_vars.cc
@@ -4872,7 +4872,8 @@ static bool fix_wsrep_causal_reads(sys_var *self, THD* thd, enum_var_type var_ty
 static Sys_var_mybool Sys_wsrep_causal_reads(
        "wsrep_causal_reads", "Setting this variable is equivalent "
        "to setting wsrep_sync_wait READ flag",
-       SESSION_VAR(wsrep_causal_reads), CMD_LINE(OPT_ARG), DEFAULT(FALSE),
+       SESSION_VAR(wsrep_causal_reads),
+       CMD_LINE(OPT_ARG, OPT_WSREP_CAUSAL_READS), DEFAULT(FALSE),
        NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(0),
        ON_UPDATE(fix_wsrep_causal_reads),
        DEPRECATED("'@@wsrep_sync_wait=1'"));
@@ -4882,7 +4883,7 @@ static Sys_var_uint Sys_wsrep_sync_wait(
        "an operation of the type specified by bitmask: 1 - READ(includes "
        "SELECT, SHOW and BEGIN/START TRANSACTION); 2 - UPDATE and DELETE; 4 - "
        "INSERT and REPLACE",
-       SESSION_VAR(wsrep_sync_wait), CMD_LINE(OPT_ARG),
+       SESSION_VAR(wsrep_sync_wait), CMD_LINE(OPT_ARG, OPT_WSREP_SYNC_WAIT),
        VALID_RANGE(WSREP_SYNC_WAIT_NONE, WSREP_SYNC_WAIT_MAX),
        DEFAULT(WSREP_SYNC_WAIT_NONE), BLOCK_SIZE(1),
        NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(0),
diff --git a/sql/wsrep_mysqld.cc b/sql/wsrep_mysqld.cc
index 7b242af2cdb..823a2a76281 100644
--- a/sql/wsrep_mysqld.cc
+++ b/sql/wsrep_mysqld.cc
@@ -561,8 +561,6 @@ int wsrep_init()
 
   wsrep_sst_auth_init(wsrep_sst_auth);
 
-  wsrep_causal_reads_update(&global_system_variables);
-
   wsrep_ready_set(FALSE);
   assert(wsrep_provider);