mysql5/mysql-5.7.27/sql/rpl_gtid_sid_map.cc

/* Copyright (c) 2011, 2016, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; version 2 of the
   License.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   02110-1301 USA */

#include "rpl_gtid.h"

#include "mysqld_error.h"    // ER_*


PSI_memory_key key_memory_Sid_map_Node;

Sid_map::Sid_map(Checkable_rwlock *_sid_lock)
  : sid_lock(_sid_lock),
    _sidno_to_sid(key_memory_Sid_map_Node), _sorted(key_memory_Sid_map_Node)
{
  DBUG_ENTER("Sid_map::Sid_map");
  my_hash_init(&_sid_to_sidno, &my_charset_bin, 20,
               offsetof(Node, sid.bytes), binary_log::Uuid::BYTE_LENGTH, NULL,
               my_free, 0,
               key_memory_Sid_map_Node);
  DBUG_VOID_RETURN;
}


Sid_map::~Sid_map()
{
  DBUG_ENTER("Sid_map::~Sid_map");
  my_hash_free(&_sid_to_sidno);
  DBUG_VOID_RETURN;
}


/*
  This code is not being used but we will keep it as it may be
  useful to optimize gtids by avoiding sharing mappings from
  sid to sidno. For instance, the IO Thread and the SQL Thread
  may have different mappings in the future.
*/
#ifdef NON_DISABLED_GTID
enum_return_status Sid_map::clear()
{
  DBUG_ENTER("Sid_map::clear");
  my_hash_free(&_sid_to_sidno);
  my_hash_init(&_sid_to_sidno, &my_charset_bin, 20,
               offsetof(Node, sid.bytes), binary_log::Uuid::BYTE_LENGTH, NULL,
               my_free, 0);
  _sidno_to_sid.clear();
  _sorted.clear();
  RETURN_OK;
}
#endif

rpl_sidno Sid_map::add_sid(const rpl_sid &sid)
{
  DBUG_ENTER("Sid_map::add_sid(const rpl_sid *)");
#ifndef DBUG_OFF
  char buf[binary_log::Uuid::TEXT_LENGTH + 1];
  sid.to_string(buf);
  DBUG_PRINT("info", ("SID=%s", buf));
#endif
  if (sid_lock)
    sid_lock->assert_some_lock();
  Node *node= (Node *)my_hash_search(&_sid_to_sidno, sid.bytes,
                                     binary_log::Uuid::BYTE_LENGTH);
  if (node != NULL)
  {
    DBUG_PRINT("info", ("existed as sidno=%d", node->sidno));
    DBUG_RETURN(node->sidno);
  }

  bool is_wrlock= false;
  if (sid_lock)
  {
    is_wrlock= sid_lock->is_wrlock();
    if (!is_wrlock)
    {
      sid_lock->unlock();
      sid_lock->wrlock();
    }
  }
  DBUG_PRINT("info", ("is_wrlock=%d sid_lock=%p", is_wrlock, sid_lock));
  rpl_sidno sidno;
  node= (Node *)my_hash_search(&_sid_to_sidno, sid.bytes,
                               binary_log::Uuid::BYTE_LENGTH);
  if (node != NULL)
    sidno= node->sidno;
  else
  {
    sidno= get_max_sidno() + 1;
    if (add_node(sidno, sid) != RETURN_STATUS_OK)
      sidno= -1;
  }

  if (sid_lock)
  {
    if (!is_wrlock)
    {
      sid_lock->unlock();
      sid_lock->rdlock();
    }
  }
  DBUG_RETURN(sidno);
}

enum_return_status Sid_map::add_node(rpl_sidno sidno, const rpl_sid &sid)
{
  DBUG_ENTER("Sid_map::add_node(rpl_sidno, const rpl_sid *)");
  if (sid_lock)
    sid_lock->assert_some_wrlock();
  Node *node= (Node *)my_malloc(key_memory_Sid_map_Node,
                                sizeof(Node), MYF(MY_WME));
  if (node == NULL)
    RETURN_REPORTED_ERROR;

  node->sidno= sidno;
  node->sid= sid;
  if (!_sidno_to_sid.push_back(node))
  {
    if (!_sorted.push_back(sidno))
    {
      if (my_hash_insert(&_sid_to_sidno, (uchar *)node) == 0)
      {
#ifdef MYSQL_SERVER
        /*
          If this is the global_sid_map, we take the opportunity to
          resize all arrays in gtid_state while holding the wrlock.
        */
        if (this != global_sid_map ||
            gtid_state->ensure_sidno() == RETURN_STATUS_OK)
#endif
        {
          // We have added one element to the end of _sorted.  Now we
          // bubble it down to the sorted position.
          int sorted_i= sidno - 1;
          rpl_sidno *prev_sorted_p= &_sorted[sorted_i];
          sorted_i--;
          while (sorted_i >= 0)
          {
            rpl_sidno *sorted_p= &_sorted[sorted_i];
            const rpl_sid &other_sid= sidno_to_sid(*sorted_p);
            if (memcmp(sid.bytes, other_sid.bytes,
                       binary_log::Uuid::BYTE_LENGTH) >= 0)
              break;
            memcpy(prev_sorted_p, sorted_p, sizeof(rpl_sidno));
            sorted_i--;
            prev_sorted_p= sorted_p;
          }
          memcpy(prev_sorted_p, &sidno, sizeof(rpl_sidno));
          RETURN_OK;
        }
      }
      _sorted.pop_back();
    }
    _sidno_to_sid.pop_back();
  }
  my_free(node);

  BINLOG_ERROR(("Out of memory."), (ER_OUT_OF_RESOURCES, MYF(0)));
  RETURN_REPORTED_ERROR;
}


enum_return_status Sid_map::copy(Sid_map *dest)
{
  DBUG_ENTER("Sid_map::copy(Sid_map)");
  enum_return_status return_status= RETURN_STATUS_OK;

  rpl_sidno max_sidno= get_max_sidno();
  for (rpl_sidno sidno= 1;
       sidno <= max_sidno && return_status == RETURN_STATUS_OK;
       sidno++)
  {
    rpl_sid sid;
    sid.copy_from(sidno_to_sid(sidno));
    return_status= dest->add_node(sidno, sid);
  }

  DBUG_RETURN(return_status);
}