MW-267 Enforce wsrep_max_ws_size limit in wsrep provider

This changes variable wsrep_max_ws_size so that its value
is linked to the value of provider option repl.max_ws_size.
That is, changing the value of variable wsrep_max_ws_size
will change the value of provider option repl.max_ws_size,
and viceversa.
The writeset size limit is always enforced in the provider,
regardless of which option is used.

mysql-test/suite/galera/r/galera_defaults.result

@@ -30,7 +30,7 @@ WSREP_FORCED_BINLOG_FORMAT	NONE
 WSREP_LOAD_DATA_SPLITTING	ON
 WSREP_LOG_CONFLICTS	OFF
 WSREP_MAX_WS_ROWS	0
-WSREP_MAX_WS_SIZE	1073741824
+WSREP_MAX_WS_SIZE	2147483647
 WSREP_MYSQL_REPLICATION_BUNDLE	0
 WSREP_NOTIFY_CMD	
 WSREP_ON	ON

mysql-test/suite/galera/r/galera_var_max_ws_size.result

@@ -5,4 +5,13 @@ ERROR HY000: Got error 5 "Input/output error" during COMMIT
 SELECT COUNT(*) = 0 FROM t1;
 COUNT(*) = 0
 1
+SET GLOBAL wsrep_provider_options = 'repl.max_ws_size=10000';
+SELECT @@wsrep_max_ws_size = 10000;
+@@wsrep_max_ws_size = 10000
+1
+SET GLOBAL wsrep_provider_options = 'repl.max_ws_size=20000';
+SET GLOBAL wsrep_provider_options = 'repl.max_ws_size=10000';
+SET GLOBAL wsrep_max_ws_size = 20000;
+provider_options_match
+1
 DROP TABLE t1;

mysql-test/suite/galera/t/galera_var_max_ws_size.test

@@ -16,6 +16,29 @@ SET GLOBAL wsrep_max_ws_size = 1024;
 INSERT INTO t1 VALUES (DEFAULT, REPEAT('X', 1024));
 SELECT COUNT(*) = 0 FROM t1;
 
+#
+# Changing repl.max_ws_size also changes wsrep_max_ws_size
+#
+
+SET GLOBAL wsrep_provider_options = 'repl.max_ws_size=10000';
+SELECT @@wsrep_max_ws_size = 10000;
+
+
+#
+# Changing wsrep_max_ws_size is equivalent to changing repl.max_ws_size
+#
+
+SET GLOBAL wsrep_provider_options = 'repl.max_ws_size=20000';
+--let $provider_options = `SELECT @@wsrep_provider_options`
+SET GLOBAL wsrep_provider_options = 'repl.max_ws_size=10000';
+
+SET GLOBAL wsrep_max_ws_size = 20000;
+--let $provider_options_updated = `SELECT @@wsrep_provider_options`
+
+--disable_query_log
+--eval SELECT STRCMP('$provider_options', '$provider_options_updated') = 0 AS provider_options_match
+--enable_query_log
+
 --disable_query_log
 --eval SET GLOBAL wsrep_max_ws_size = $wsrep_max_ws_size_orig
 --enable_query_log

sql/sys_vars.cc

@@ -4688,8 +4688,9 @@ static Sys_var_charptr Sys_wsrep_start_position (
 static Sys_var_ulong Sys_wsrep_max_ws_size (
        "wsrep_max_ws_size", "Max write set size (bytes)",
        GLOBAL_VAR(wsrep_max_ws_size), CMD_LINE(REQUIRED_ARG),
-       /* Upper limit is 65K short of 4G to avoid overlows on 32-bit systems */
-       VALID_RANGE(1024, WSREP_MAX_WS_SIZE), DEFAULT(1073741824UL), BLOCK_SIZE(1));
+       VALID_RANGE(1024, WSREP_MAX_WS_SIZE), DEFAULT(WSREP_MAX_WS_SIZE),
+       BLOCK_SIZE(1), NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(0),
+       ON_UPDATE(wsrep_max_ws_size_update));
 
 static Sys_var_ulong Sys_wsrep_max_ws_rows (
        "wsrep_max_ws_rows", "Max number of rows in write set",

sql/wsrep_applier.cc

@@ -39,15 +39,9 @@ static Log_event* wsrep_read_log_event(
   const char *error= 0;
   Log_event *res=  0;
 
-  if (data_len > wsrep_max_ws_size)
-  {
-    error = "Event too big";
-    goto err;
-  }
-
-  res= Log_event::read_log_event(buf, data_len, &error, description_event, true);
+  res= Log_event::read_log_event(buf, data_len, &error, description_event,
+                                 true);
 
-err:
   if (!res)
   {
     DBUG_ASSERT(error != 0);

sql/wsrep_binlog.h

@@ -19,7 +19,7 @@
 #include "sql_class.h" // THD, IO_CACHE
 
 #define HEAP_PAGE_SIZE 65536 /* 64K */
-#define WSREP_MAX_WS_SIZE (0xFFFFFFFFUL - HEAP_PAGE_SIZE)
+#define WSREP_MAX_WS_SIZE 2147483647 /* 2GB */
 
 /*
   Write the contents of a cache to a memory buffer.

sql/wsrep_var.cc

@@ -179,6 +179,32 @@ void wsrep_start_position_init (const char* val)
   wsrep_set_local_position (val, false);
 }
 
+static int get_provider_option_value(const char* opts,
+                                     const char* opt_name,
+                                     ulong* opt_value)
+{
+  int ret= 1;
+  ulong opt_value_tmp;
+  char *opt_value_str, *s, *opts_copy= my_strdup(opts, MYF(MY_WME));
+
+  if ((opt_value_str= strstr(opts_copy, opt_name)) == NULL)
+    goto end;
+  opt_value_str= strtok_r(opt_value_str, "=", &s);
+  if (opt_value_str == NULL) goto end;
+  opt_value_str= strtok_r(NULL, ";", &s);
+  if (opt_value_str == NULL) goto end;
+
+  opt_value_tmp= strtoul(opt_value_str, NULL, 10);
+  if (errno == ERANGE) goto end;
+
+  *opt_value= opt_value_tmp;
+  ret= 0;
+
+end:
+  my_free(opts_copy);
+  return ret;
+}
+
 static bool refresh_provider_options()
 {
   WSREP_DEBUG("refresh_provider_options: %s", 
@@ -186,9 +212,10 @@ static bool refresh_provider_options()
   char* opts= wsrep->options_get(wsrep);
   if (opts)
   {
-    if (wsrep_provider_options) my_free((void *)wsrep_provider_options);
-    wsrep_provider_options = (char*)my_memdup(opts, strlen(opts) + 1, 
-                                              MYF(MY_WME));
+    wsrep_provider_options_init(opts);
+    get_provider_option_value(wsrep_provider_options,
+                              (char*)"repl.max_ws_size",
+                              &wsrep_max_ws_size);
   }
   else
   {
@@ -531,6 +558,21 @@ bool wsrep_desync_update (sys_var *self, THD* thd, enum_var_type type)
   return false;
 }
 
+bool wsrep_max_ws_size_update (sys_var *self, THD *thd, enum_var_type)
+{
+  char max_ws_size_opt[128];
+  my_snprintf(max_ws_size_opt, sizeof(max_ws_size_opt),
+              "repl.max_ws_size=%d", wsrep_max_ws_size);
+  wsrep_status_t ret= wsrep->options_set(wsrep, max_ws_size_opt);
+  if (ret != WSREP_OK)
+  {
+    WSREP_ERROR("Set options returned %d", ret);
+    refresh_provider_options();
+    return true;
+  }
+  return refresh_provider_options();
+}
+
 /*
  * Status variables stuff below
  */

sql/wsrep_var.h

@@ -83,4 +83,6 @@ extern bool wsrep_slave_threads_update       UPDATE_ARGS;
 extern bool wsrep_desync_check               CHECK_ARGS;
 extern bool wsrep_desync_update              UPDATE_ARGS;
 
+extern bool wsrep_max_ws_size_update         UPDATE_ARGS;
+
 #endif /* WSREP_VAR_H */