Add semisync functionality to mysqlbinlog

Summary:
WebScaleSQL Feature: Semisync Log Tailers

Share the semisync_slave plugin code to use for semisync functionality
in mysqlbinlog.  mysqlbinlog sends acknowledgement for events which
require a semi sync reply.

Since mysqlbinlog now speaks semi-sync portocol, we force the semi-sync
plugin to be built regardless of the option WITHOUT_SERVER.

Test Plan:
mysqlbinlog with and without --semisync-debug
mtr test to verify mysqlbinlog slave is acknowledging
for events it received.

This has been used in production at Facebook for > 9 months.

Reviewers: darnaut, inaam-rana, pivanof, jeremycole

Reviewed By: pivanof, jeremycole

Subscribers: steaphan, jtolmer, CalvinSun

Differential Revision: https://reviews.facebook.net/D24171
Differential Revision: https://reviews.facebook.net/D32763

CMakeLists.txt

@@ -430,6 +430,8 @@ IF(NOT WITHOUT_SERVER)
 ELSE()
   # We may still want Cluster client libraries, use -DWITH_NDBCLUSTER=1
   ADD_SUBDIRECTORY(storage/ndb)
+  # mysqlbinlog needs semi-sync
+  ADD_SUBDIRECTORY(${CMAKE_SOURCE_DIR}/plugin/semisync/)
 ENDIF()
 
 ADD_SUBDIRECTORY(include)

client/CMakeLists.txt

@@ -24,6 +24,7 @@ INCLUDE_DIRECTORIES(
   ${CMAKE_SOURCE_DIR}/strings
   ${EDITLINE_INCLUDE_DIR}
   ${CMAKE_CURRENT_BINARY_DIR}
+  ${CMAKE_SOURCE_DIR}/plugin/semisync
 )
 
 
@@ -62,7 +63,7 @@ MYSQL_ADD_EXECUTABLE(mysql_plugin mysql_plugin.c)
 TARGET_LINK_LIBRARIES(mysql_plugin mysqlclient)
 
 MYSQL_ADD_EXECUTABLE(mysqlbinlog mysqlbinlog.cc)
-TARGET_LINK_LIBRARIES(mysqlbinlog mysqlclient)
+TARGET_LINK_LIBRARIES(mysqlbinlog mysqlclient semisync_slave_client)
 
 MYSQL_ADD_EXECUTABLE(mysqladmin mysqladmin.cc)
 TARGET_LINK_LIBRARIES(mysqladmin mysqlclient)

client/client_priv.h

@@ -100,6 +100,8 @@ enum options_client
   OPT_SERVER_PUBLIC_KEY,
   OPT_ENABLE_CLEARTEXT_PLUGIN,
   OPT_CONNECTION_SERVER_ID,
+  OPT_USE_SEMISYNC,
+  OPT_SEMISYNC_DEBUG,
   OPT_MAX_CLIENT_OPTION
 };
 

client/mysqlbinlog.cc

@@ -54,6 +54,7 @@ static void warning(const char *format, ...) ATTRIBUTE_FORMAT(printf, 1, 2);
 #include "sql_string.h"
 #include "my_decimal.h"
 #include "rpl_constants.h"
+#include "semisync_slave_client.h"
 
 #include <algorithm>
 
@@ -193,6 +194,9 @@ static bool filter_based_on_gtids= false;
 
 static bool in_transaction= false;
 static bool seen_gtids= false;
+static bool opt_use_semisync = false;
+static uint opt_semisync_debug = 0;
+ReplSemiSyncSlave repl_semisync;
 
 static Exit_status dump_local_log_entries(PRINT_EVENT_INFO *print_event_info,
                                           const char* logname);
@@ -1615,6 +1619,17 @@ static struct my_option my_long_options[] =
    "Identifiers were provided.",
    &opt_exclude_gtids_str, &opt_exclude_gtids_str, 0,
    GET_STR_ALLOC, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
+  {"use-semisync", OPT_USE_SEMISYNC,
+   "mysqlbinlog functions as a semisync slave sending acknowledgement "
+   "for received events.",
+   &opt_use_semisync, &opt_use_semisync, 0,
+   GET_BOOL, OPT_ARG, 0, 0, 0, 0, 0, 0},
+  {"semisync-debug", OPT_SEMISYNC_DEBUG,
+   "A value of 2 prints debug information of semi-sync. "
+   "A value of 1 prints function traces of semi-sync. "
+   "A value of of 0 doesn't print any debug information.",
+   &opt_semisync_debug, &opt_semisync_debug, 0,
+   GET_UINT, REQUIRED_ARG, 0, 0, 2, 1, 0, 0},
   {0, 0, 0, 0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0}
 };
 
@@ -1651,21 +1666,6 @@ static void error(const char *format,...)
   va_end(args);
 }
 
-
-/**
-  This function is used in log_event.cc to report errors.
-
-  @param format Printf-style format string, followed by printf
-  varargs.
-*/
-static void sql_print_error(const char *format,...)
-{
-  va_list args;
-  va_start(args, format);
-  error_or_warning(format, args, "ERROR");
-  va_end(args);
-}
-
 /**
   Prints a message to stderr, prefixed with the text "WARNING: " and
   suffixed with a newline.
@@ -1879,7 +1879,26 @@ static Exit_status safe_connect()
     error("Failed on connect: %s", mysql_error(mysql));
     return ERROR_STOP;
   }
-  mysql->reconnect= 1;
+  if (opt_use_semisync)
+  {
+    // set semi sync slave status to true
+    rpl_semi_sync_slave_enabled = 1;
+    // Note that kTraceDetail and kTraceFunction are the only trace
+    // levels used by semi-sync slave.
+    if (opt_semisync_debug == 2)
+      rpl_semi_sync_slave_trace_level = Trace::kTraceDetail;
+    else if (opt_semisync_debug == 1)
+      rpl_semi_sync_slave_trace_level = Trace::kTraceFunction;
+    else
+      rpl_semi_sync_slave_trace_level = 0;
+    // Initialize semi sync slave functionality
+    repl_semisync.initObject();
+    // Check with master if it has semisync enabled and notify
+    // master this is a semisync enabled slave.
+    if (repl_semisync.slaveRequestDump(mysql))
+      return ERROR_STOP;
+  }
+  mysql->reconnect= 0;
   return OK_CONTINUE;
 }
 
@@ -2112,9 +2131,12 @@ static Exit_status dump_remote_log_entries(PRINT_EVENT_INFO *print_event_info,
   my_off_t old_off= start_position_mot;
   char fname[FN_REFLEN + 1];
   char log_file_name[FN_REFLEN + 1];
+  char *log_file = NULL;
   Exit_status retval= OK_CONTINUE;
   enum enum_server_command command= COM_END;
 
+  bool semi_sync_need_reply = false;
+
   DBUG_ENTER("dump_remote_log_entries");
 
   fname[0]= log_file_name[0]= 0;
@@ -2258,8 +2280,24 @@ static Exit_status dump_remote_log_entries(PRINT_EVENT_INFO *print_event_info,
       ROTATE_EVENT or FORMAT_DESCRIPTION_EVENT
     */
 
-    type= (Log_event_type) net->read_pos[1 + EVENT_TYPE_OFFSET];
-
+    const char *event_buf = (const char*)net->read_pos + 1;
+    ulong event_len = len - 1;
+    if (rpl_semi_sync_slave_status)
+    {
+      // semisync event has 2 extra flags at the beginning of the event
+      // header.
+      type = (Log_event_type) net->read_pos[1 + 2 + EVENT_TYPE_OFFSET];
+      if (repl_semisync.slaveReadSyncHeader((const char*)net->read_pos + 1,
+                                        event_len, &semi_sync_need_reply,
+                                        &event_buf, &event_len)) {
+        error("Malformed semi-sync packet");
+        DBUG_RETURN(ERROR_STOP);
+      }
+    }
+    else
+    {
+      type = (Log_event_type) net->read_pos[1 + EVENT_TYPE_OFFSET];
+    }
     /*
       Ignore HEARBEAT events. They can show up if mysqlbinlog is
       running with:
@@ -2276,8 +2314,7 @@ static Exit_status dump_remote_log_entries(PRINT_EVENT_INFO *print_event_info,
 
     if (!raw_mode || (type == ROTATE_EVENT) || (type == FORMAT_DESCRIPTION_EVENT))
     {
-      if (!(ev= Log_event::read_log_event((const char*) net->read_pos + 1 ,
-                                          len - 1, &error_msg,
+      if (!(ev= Log_event::read_log_event(event_buf, event_len, &error_msg,
                                           glob_description_event,
                                           opt_verify_binlog_checksum)))
       {
@@ -2288,7 +2325,7 @@ static Exit_status dump_remote_log_entries(PRINT_EVENT_INFO *print_event_info,
         If reading from a remote host, ensure the temp_buf for the
         Log_event class is pointing to the incoming stream.
       */
-      ev->register_temp_buf((char *) net->read_pos + 1);
+      ev->register_temp_buf((char *)event_buf);
     }
     if (raw_mode || (type != LOAD_EVENT))
     {
@@ -2322,6 +2359,7 @@ static Exit_status dump_remote_log_entries(PRINT_EVENT_INFO *print_event_info,
           {
             strmov(log_file_name, rev->new_log_ident);
           }
+          log_file = log_file_name + dirname_length(log_file_name);
         }
 
         if (rev->when.tv_sec == 0)
@@ -2346,7 +2384,7 @@ static Exit_status dump_remote_log_entries(PRINT_EVENT_INFO *print_event_info,
              next binlog file (fake rotate) picked by mysqlbinlog --to-last-log
          */
           old_off= start_position_mot;
-          len= 1; // fake Rotate, so don't increment old_off
+          event_len = 0; // fake Rotate, so don't increment old_off
         }
       }
       else if (type == FORMAT_DESCRIPTION_EVENT)
@@ -2360,7 +2398,7 @@ static Exit_status dump_remote_log_entries(PRINT_EVENT_INFO *print_event_info,
         */
         // fake event when not in raw mode, don't increment old_off
         if ((old_off != BIN_LOG_HEADER_SIZE) && (!raw_mode))
-          len= 1;
+          event_len = 0;
         if (raw_mode)
         {
           if (result_file && (result_file != stdout))
@@ -2403,7 +2441,8 @@ static Exit_status dump_remote_log_entries(PRINT_EVENT_INFO *print_event_info,
       {
         DBUG_EXECUTE_IF("simulate_result_file_write_error",
                         DBUG_SET("+d,simulate_fwrite_error"););
-        if (my_fwrite(result_file, net->read_pos + 1 , len - 1, MYF(MY_NABP)))
+        if (my_fwrite(result_file, (const uchar*) event_buf, event_len,
+            MYF(MY_NABP)))
         {
           error("Could not write into log file '%s'", log_file_name);
           retval= ERROR_STOP;
@@ -2447,7 +2486,12 @@ static Exit_status dump_remote_log_entries(PRINT_EVENT_INFO *print_event_info,
       Let's adjust offset for remote log as for local log to produce
       similar text and to have --stop-position to work identically.
     */
-    old_off+= len-1;
+    old_off += event_len;
+    if (rpl_semi_sync_slave_status && semi_sync_need_reply)
+    {
+      DBUG_ASSERT(raw_mode);
+      repl_semisync.slaveReply(mysql, log_file, old_off);
+    }
   }
 
   DBUG_RETURN(OK_CONTINUE);
@@ -2869,6 +2913,12 @@ static int args_post_process(void)
           stop_never_slave_server_id);
 #endif
 
+  if (opt_use_semisync && !raw_mode)
+  {
+    error("--raw option must be used when using --use_semisync option");
+    DBUG_RETURN(ERROR_STOP);
+  }
+
   DBUG_RETURN(OK_CONTINUE);
 }
 

mysql-test/r/semisync_mysqlbinlog.result

@@ -0,0 +1,71 @@
+set @save_master_timeout=@@global.rpl_semi_sync_master_timeout;
+set @save_master_wait_no_slave=@@global.rpl_semi_sync_master_wait_no_slave;
+set @save_master_enabled=@@global.rpl_semi_sync_master_enabled;
+[ enable semi-sync on master ]
+set global rpl_semi_sync_master_timeout= 60000 /* 60s */;
+set global rpl_semi_sync_master_enabled = 1;
+show variables like 'rpl_semi_sync_master_enabled';
+Variable_name	Value
+rpl_semi_sync_master_enabled	ON
+[ status of semi-sync on master should be ON even without any semi-sync slaves ]
+show status like 'Rpl_semi_sync_master_clients';
+Variable_name	Value
+Rpl_semi_sync_master_clients	0
+show status like 'Rpl_semi_sync_master_status';
+Variable_name	Value
+Rpl_semi_sync_master_status	ON
+show status like 'Rpl_semi_sync_master_yes_tx';
+Variable_name	Value
+Rpl_semi_sync_master_yes_tx	0
+[ initial master state after the semi-sync mysqlbinlog connected ]
+show status like 'Rpl_semi_sync_master_clients';
+Variable_name	Value
+Rpl_semi_sync_master_clients	1
+show status like 'Rpl_semi_sync_master_status';
+Variable_name	Value
+Rpl_semi_sync_master_status	ON
+show status like 'Rpl_semi_sync_master_no_tx';
+Variable_name	Value
+Rpl_semi_sync_master_no_tx	0
+show status like 'Rpl_semi_sync_master_yes_tx';
+Variable_name	Value
+Rpl_semi_sync_master_yes_tx	0
+create table t1(a int) engine = Innodb;
+[ master state after CREATE TABLE statement ]
+show status like 'Rpl_semi_sync_master_status';
+Variable_name	Value
+Rpl_semi_sync_master_status	ON
+show status like 'Rpl_semi_sync_master_no_tx';
+Variable_name	Value
+Rpl_semi_sync_master_no_tx	0
+show status like 'Rpl_semi_sync_master_yes_tx';
+Variable_name	Value
+Rpl_semi_sync_master_yes_tx	1
+[ insert records to table ]
+[ master status after inserts ]
+show status like 'Rpl_semi_sync_master_status';
+Variable_name	Value
+Rpl_semi_sync_master_status	ON
+show status like 'Rpl_semi_sync_master_no_tx';
+Variable_name	Value
+Rpl_semi_sync_master_no_tx	0
+show status like 'Rpl_semi_sync_master_yes_tx';
+Variable_name	Value
+Rpl_semi_sync_master_yes_tx	11
+set global rpl_semi_sync_master_wait_no_slave = OFF;
+show variables like 'rpl_semi_sync_master_wait_no_slave';
+Variable_name	Value
+rpl_semi_sync_master_wait_no_slave	OFF
+show variables like 'rpl_semi_sync_master_enabled';
+Variable_name	Value
+rpl_semi_sync_master_enabled	ON
+show status like 'Rpl_semi_sync_master_status';
+Variable_name	Value
+Rpl_semi_sync_master_status	ON
+#
+# Clean up
+#
+set @@global.rpl_semi_sync_master_timeout=@save_master_timeout;
+set @@global.rpl_semi_sync_master_wait_no_slave=@save_master_wait_no_slave;
+set @@global.rpl_semi_sync_master_enabled=@save_master_enabled;
+drop table t1;

mysql-test/t/semisync_mysqlbinlog-master.opt

@@ -0,0 +1,2 @@
+$SEMISYNC_PLUGIN_OPT
+--force-restart