SHOW NEW MASTER FOR SLAVE WITH ...

2025-08-07 00:04:31 +03:00 · 2001-07-04 17:14:31 -06:00
parent a973b85527
commit c01d4e1ef7
31 changed files with 367 additions and 3 deletions
--- a/sql/sql_repl.cc
+++ b/sql/sql_repl.cc
@@ -26,6 +26,7 @@
 #include <my_dir.h>

 #define SLAVE_LIST_CHUNK 128
+#define SLAVE_ERRMSG_SIZE (FN_REFLEN+64)

 extern const char* any_db;
 extern pthread_handler_decl(handle_slave,arg);
@@ -38,6 +39,10 @@ bool opt_sporadic_binlog_dump_fail = 0;
 static int binlog_dump_count = 0;
 #endif

+static Slave_log_event* find_slave_event(IO_CACHE* log,
+					 const char* log_file_name,
+					 char* errmsg);
+
 static uint32* slave_list_key(SLAVE_INFO* si, uint* len,
 			     my_bool not_used __attribute__((unused)))
 {
@@ -863,6 +868,272 @@ void reset_master()

 }

+int cmp_master_pos(const char* log_file_name1, ulonglong log_pos1,
+		   const char* log_file_name2, ulonglong log_pos2)
+{
+  int res;
+  if ((res = strcmp(log_file_name1, log_file_name2)))
+    return res;
+  if (log_pos1 > log_pos2)
+    return 1;
+  else if (log_pos1 == log_pos2)
+    return 0;
+  return -1;
+}
+
+static inline int cmp_master_pos(Slave_log_event* sev, LEX_MASTER_INFO* mi)
+{
+  return cmp_master_pos(sev->master_log, sev->master_pos, mi->log_file_name,
+			mi->pos);
+}
+
+static int find_target_pos(LEX_MASTER_INFO* mi, IO_CACHE* log, char* errmsg)
+{
+  uint32 log_seq = mi->last_log_seq;
+  uint32 target_server_id = mi->server_id;
+  
+  for (;;)
+  {
+    Log_event* ev;
+    if (!(ev = Log_event::read_log_event(log, 0)))
+    {
+      if (log->error > 0)
+	strmov(errmsg, "Binary log truncated in the middle of event");
+      else if(log->error < 0)
+	strmov(errmsg, "I/O error reading binary log");
+      else
+	strmov(errmsg, "Could not find target event in the binary log");
+      return 1;
+    }
+
+    if (ev->log_seq == log_seq && ev->server_id == target_server_id)
+    {
+      delete ev;
+      mi->pos = my_b_tell(log);
+      return 0;
+    }
+
+    delete ev;
+  }
+}
+
+static void copy_base_name(char* dest, char* src)
+{
+  char* p;
+  p = strrchr(src, FN_LIBCHAR);
+  if (p)
+    p++;
+  else
+    p = src;
+  strmov(dest, p);
+}
+
+int translate_master(THD* thd, LEX_MASTER_INFO* mi, char* errmsg)
+{
+  LOG_INFO linfo;
+  char search_file_name[FN_REFLEN],last_log_name[FN_REFLEN];
+  IO_CACHE log, last_log;
+  File file = -1, last_file = -1;
+  pthread_mutex_t *log_lock;
+  const char* errmsg_p;
+  Slave_log_event* sev = 0;
+  my_off_t last_pos = 0;
+  int error = 1;
+  int cmp_res;
+  LINT_INIT(cmp_res);
+  
+  if (!mysql_bin_log.is_open())
+  {
+    strmov(errmsg,"Binary log is not open");
+    return 1;
+  }
+
+  if (!server_id_supplied)
+  {
+    strmov(errmsg, "Misconfigured master - server id was not set");
+    return 1;
+  }
+  
+  linfo.index_file_offset = 0;
+  thd->current_linfo = &linfo;
+  search_file_name[0] = 0;
+
+  if (mysql_bin_log.find_first_log(&linfo, search_file_name))
+  {
+    strmov(errmsg,"Could not find first log");
+    return 1;
+  }
+  
+  bzero((char*) &log,sizeof(log));
+  log_lock = mysql_bin_log.get_log_lock();
+  pthread_mutex_lock(log_lock);
+  
+  for (;;)
+  {
+    
+    if ((file=open_binlog(&log, linfo.log_file_name, &errmsg_p)) < 0)
+    {
+      pthread_mutex_unlock(log_lock);
+      strmov(errmsg, errmsg_p);
+      goto err;
+    }
+    
+    if (!(sev = find_slave_event(&log, linfo.log_file_name, errmsg)))
+    {
+      pthread_mutex_unlock(log_lock);
+      goto err;
+    }
+    
+    cmp_res = cmp_master_pos(sev, mi);
+    delete sev;
+    
+    if(!cmp_res)
+    {
+      pthread_mutex_unlock(log_lock);
+      copy_base_name(mi->log_file_name, linfo.log_file_name);
+      mi->pos = my_b_tell(&log);
+      goto mi_inited;
+    }
+    
+    if (!last_pos && cmp_res > 0)
+    {
+      pthread_mutex_unlock(log_lock);
+      strmov(errmsg, "Slave event in first log points past the \
+target position");
+      goto err;
+    }
+
+    if (last_pos && cmp_res > 0)
+    {
+      end_io_cache(&log);
+      (void) my_close(file, MYF(MY_WME));
+      if (init_io_cache(&log, (file = last_file), IO_SIZE, READ_CACHE, 0, 0,
+			MYF(MY_WME)))
+      {
+	errmsg[0] = 0;
+	goto err;
+      }
+
+      goto found_log;
+    }
+    
+    strmov(last_log_name, linfo.log_file_name);
+    last_pos = my_b_tell(&log);
+
+    switch (mysql_bin_log.find_next_log(&linfo))
+    {
+    case LOG_INFO_EOF:
+      if (last_file >= 0)
+       (void)my_close(last_file, MYF(MY_WME));
+      last_file = -1;
+      goto found_log;
+    case 0:
+      break;
+    default:
+      pthread_mutex_unlock(log_lock);
+      strmov(errmsg, "Error reading log index");
+      goto err;
+    }
+    
+    end_io_cache(&log);
+    if (last_file >= 0)
+     (void) my_close(last_file, MYF(MY_WME));
+    last_file = file;
+  }
+  
+found_log:
+  my_b_seek(&log, last_pos);
+  if (find_target_pos(mi,&log,errmsg))
+  {
+    pthread_mutex_unlock(log_lock);
+    goto err;
+  }
+  pthread_mutex_unlock(log_lock);
+  copy_base_name(mi->log_file_name, last_log_name);
+mi_inited:  
+  error = 0;
+err:
+  end_io_cache(&log);
+  pthread_mutex_lock(&LOCK_thread_count);
+  thd->current_linfo = 0;
+  pthread_mutex_unlock(&LOCK_thread_count);
+  if (file >= 0)
+    (void) my_close(file, MYF(MY_WME));
+  if (last_file >= 0 && last_file != file)
+    (void) my_close(last_file, MYF(MY_WME));
+
+  return error;
+}
+
+// caller must delete result when done
+static Slave_log_event* find_slave_event(IO_CACHE* log,
+					 const char* log_file_name,
+					 char* errmsg)
+{
+  Log_event* ev;
+  if (!(ev = Log_event::read_log_event(log, 0)))
+  {
+    my_vsnprintf(errmsg, SLAVE_ERRMSG_SIZE,
+		 "Error reading start event in log '%s'",
+		 (char*)log_file_name);
+    return 0;
+  }
+    
+  delete ev;
+    
+  if (!(ev = Log_event::read_log_event(log, 0)))
+  {
+    my_vsnprintf(errmsg, SLAVE_ERRMSG_SIZE,
+		 "Error reading slave event in log '%s'",
+		 (char*)log_file_name);
+    return 0;
+  }
+
+  if (ev->get_type_code() != SLAVE_EVENT)
+  {
+    my_vsnprintf(errmsg, SLAVE_ERRMSG_SIZE,
+		 "Second event in log '%s' is not slave event",
+		 (char*)log_file_name);
+    delete ev;
+    return 0;
+  }
+
+  return (Slave_log_event*)ev;
+}
+
+int show_new_master(THD* thd)
+{
+  DBUG_ENTER("show_new_master");
+  List<Item> field_list;
+  char errmsg[SLAVE_ERRMSG_SIZE];
+  LEX_MASTER_INFO* lex_mi = &thd->lex.mi;
+  
+  if (translate_master(thd, lex_mi, errmsg))
+  {
+    if (errmsg[0])
+      net_printf(&thd->net, ER_SHOW_NEW_MASTER, errmsg);
+    else
+      send_error(&thd->net, 0);
+    
+    DBUG_RETURN(1);
+  }
+  else
+  {
+    String* packet = &thd->packet;
+    field_list.push_back(new Item_empty_string("Log_name", 20));
+    field_list.push_back(new Item_empty_string("Log_pos", 20));
+    if (send_fields(thd, field_list, 1))
+      DBUG_RETURN(-1);
+    packet->length(0);
+    net_store_data(packet, lex_mi->log_file_name);
+    net_store_data(packet, (longlong)lex_mi->pos);
+    if (my_net_write(&thd->net, packet->ptr(), packet->length()))
+      DBUG_RETURN(-1);
+    send_eof(&thd->net);
+    DBUG_RETURN(0);
+  }
+
+}

 int show_binlog_events(THD* thd)
 {
@@ -913,7 +1184,6 @@ int show_binlog_events(THD* thd)
    }

    pthread_mutex_lock(mysql_bin_log.get_log_lock());
- 
    my_b_seek(&log, pos);

    for (event_count = 0;