mariadb/sql/wsrep_applier.cc

/* Copyright (C) 2013-2015 Codership Oy <info@codership.com>

   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 Street, Fifth Floor, Boston, MA 02110-1335 USA. */

#include "mariadb.h"
#include "mysql/service_wsrep.h"
#include "wsrep_applier.h"

#include "wsrep_priv.h"
#include "wsrep_binlog.h" // wsrep_dump_rbr_buf()
#include "wsrep_xid.h"
#include "wsrep_thd.h"
#include "wsrep_trans_observer.h"

#include "slave.h" // opt_log_slave_updates
#include "log_event.h" // class THD, EVENT_LEN_OFFSET, etc.
#include "debug_sync.h"

/*
  read the first event from (*buf). The size of the (*buf) is (*buf_len).
  At the end (*buf) is shitfed to point to the following event or NULL and
  (*buf_len) will be changed to account just being read bytes of the 1st event.
*/
static Log_event* wsrep_read_log_event(
    char **arg_buf, size_t *arg_buf_len,
    const Format_description_log_event *description_event)
{
  DBUG_ENTER("wsrep_read_log_event");
  char *head= (*arg_buf);

  uint data_len= uint4korr(head + EVENT_LEN_OFFSET);
  char *buf= (*arg_buf);
  const char *error= 0;
  Log_event *res=  0;

  res= Log_event::read_log_event(buf, data_len, &error, description_event,
                                 true);

  if (!res)
  {
    DBUG_ASSERT(error != 0);
    sql_print_error("Error in Log_event::read_log_event(): "
                    "'%s', data_len: %d, event_type: %d",
                    error,data_len,head[EVENT_TYPE_OFFSET]);
  }
  (*arg_buf)+= data_len;
  (*arg_buf_len)-= data_len;
  DBUG_RETURN(res);
}

#include "transaction.h" // trans_commit(), trans_rollback()
#include "rpl_rli.h"     // class Relay_log_info;

void wsrep_set_apply_format(THD* thd, Format_description_log_event* ev)
{
  if (thd->wsrep_apply_format)
  {
    delete (Format_description_log_event*)thd->wsrep_apply_format;
  }
  thd->wsrep_apply_format= ev;
}

Format_description_log_event*
wsrep_get_apply_format(THD* thd)
{
  if (thd->wsrep_apply_format)
  {
    return (Format_description_log_event*) thd->wsrep_apply_format;
  }

  DBUG_ASSERT(thd->wsrep_rgi);

  return thd->wsrep_rgi->rli->relay_log.description_event_for_exec;
}

void wsrep_apply_error::store(const THD* const thd)
{
  Diagnostics_area::Sql_condition_iterator it=
    thd->get_stmt_da()->sql_conditions();
  const Sql_condition* cond;

  static size_t const max_len= 2*MAX_SLAVE_ERRMSG; // 2x so that we have enough

  if (NULL == str_)
  {
    // this must be freeable by standard free()
    str_= static_cast<char*>(malloc(max_len));
    if (NULL == str_)
    {
      WSREP_ERROR("Failed to allocate %zu bytes for error buffer.", max_len);
      len_= 0;
      return;
    }
  }
  else
  {
    /* This is possible when we invoke rollback after failed applying.
     * In this situation DA should not be reset yet and should contain
     * all previous errors from applying and new ones from rollbacking,
     * so we just overwrite is from scratch */
  }

  char* slider= str_;
  const char* const buf_end= str_ + max_len - 1; // -1: leave space for \0

  for (cond= it++; cond && slider < buf_end; cond= it++)
  {
    uint const err_code= cond->get_sql_errno();
    const char* const err_str= cond->get_message_text();

    slider+= my_snprintf(slider, buf_end - slider, " %s, Error_code: %d;",
                         err_str, err_code);
  }

  *slider= '\0';
  len_= slider - str_ + 1; // +1: add \0

  WSREP_DEBUG("Error buffer for thd %llu seqno %lld, %zu bytes: %s",
              thd->thread_id, (long long)wsrep_thd_trx_seqno(thd),
              len_, str_ ? str_ : "(null)");
}

int wsrep_apply_events(THD*        thd,
                       Relay_log_info* rli,
                       const void* events_buf,
                       size_t      buf_len)
{
  char *buf= (char *)events_buf;
  int rcode= 0;
  int event= 1;
  Log_event_type typ;

  DBUG_ENTER("wsrep_apply_events");
  if (!buf_len) WSREP_DEBUG("empty rbr buffer to apply: %lld",
                            (long long) wsrep_thd_trx_seqno(thd));

  while (buf_len)
  {
    int exec_res;
    Log_event* ev= wsrep_read_log_event(&buf, &buf_len,
                                          wsrep_get_apply_format(thd));
    if (!ev)
    {
      WSREP_ERROR("applier could not read binlog event, seqno: %lld, len: %zu",
                  (long long)wsrep_thd_trx_seqno(thd), buf_len);
      rcode= WSREP_ERR_BAD_EVENT;
      goto error;
    }

    typ= ev->get_type_code();

    switch (typ) {
    case FORMAT_DESCRIPTION_EVENT:
      wsrep_set_apply_format(thd, (Format_description_log_event*)ev);
      continue;
#ifdef GTID_SUPPORT
    case GTID_LOG_EVENT:
    {
      Gtid_log_event* gev= (Gtid_log_event*)ev;
      if (gev->get_gno() == 0)
      {
        /* Skip GTID log event to make binlog to generate LTID on commit */
        delete ev;
        continue;
      }
    }
#endif /* GTID_SUPPORT */
    default:
      break;
    }

    /* Use the original server id for logging. */
    thd->set_server_id(ev->server_id);
    thd->set_time();                            // time the query
    thd->transaction.start_time.reset(thd);
    thd->lex->current_select= 0;
    if (!ev->when)
    {
      my_hrtime_t hrtime= my_hrtime();
      ev->when= hrtime_to_my_time(hrtime);
      ev->when_sec_part= hrtime_sec_part(hrtime);
    }

    thd->variables.option_bits=
      (thd->variables.option_bits & ~OPTION_SKIP_REPLICATION) |
      (ev->flags & LOG_EVENT_SKIP_REPLICATION_F ?  OPTION_SKIP_REPLICATION : 0);

    ev->thd= thd;
    exec_res= ev->apply_event(thd->wsrep_rgi);
    DBUG_PRINT("info", ("exec_event result: %d", exec_res));

    if (exec_res)
    {
      WSREP_WARN("Event %d %s apply failed: %d, seqno %lld",
                 event, ev->get_type_str(), exec_res,
                 (long long) wsrep_thd_trx_seqno(thd));
      rcode= exec_res;
      /* stop processing for the first error */
      delete ev;
      goto error;
    }
    event++;

    delete_or_keep_event_post_apply(thd->wsrep_rgi, typ, ev);
  }

error:
  if (thd->killed == KILL_CONNECTION)
    WSREP_INFO("applier aborted: %lld", (long long)wsrep_thd_trx_seqno(thd));

  wsrep_set_apply_format(thd, NULL);

  DBUG_RETURN(rcode);
}