Commit a4ff3120 authored by aelkin@mysql.com's avatar aelkin@mysql.com
Browse files

Bug#17263 temporary tables and replication 

  Backporting a changeset made for 5.0. Comments from there:

  The fix refines the algorithm of generating DROPs for binlog.
  Temp tables with common pseudo_thread_id are clustered into one query.
  Consequently one replication event per pseudo_thread_id is generated.
parent 50e8e58c

mysql-test/r/rpl_temporary.result

+14 −0
Original line number Diff line number Diff line
@@ -89,3 +89,17 @@ f 
7

drop table t1,t2;

create temporary table t3 (f int);

set @session.pseudo_thread_id=100;

create temporary table t101 (id int);

create temporary table t102 (id int);

set @session.pseudo_thread_id=200;

create temporary table t201 (id int);

create temporary table `#not_user_table_prefixed_with_hash_sign_no_harm` (id int);

set @con1_id=connection_id();

kill @con1_id;

create table t1(f int);

insert into t1 values (1);

select * from t1 /* must be 1 */;

f

1

drop table t1;

mysql-test/t/rpl_temporary.test

+27 −1
Original line number Diff line number Diff line
@@ -128,6 +128,32 @@ drop table t1,t2; 
create temporary table t3 (f int);

sync_with_master;



# The server will now close done

#

# BUG#17263 incorrect generation DROP temp tables

# Temporary tables of connection are dropped in batches

# where a batch correspond to pseudo_thread_id

# value was set up at the moment of temp table creation

#

connection con1;

set @session.pseudo_thread_id=100;

create temporary table t101 (id int);

create temporary table t102 (id int);

set @session.pseudo_thread_id=200;

create temporary table t201 (id int);

create temporary table `#not_user_table_prefixed_with_hash_sign_no_harm` (id int);

set @con1_id=connection_id();

kill @con1_id;



#now do something to show that slave is ok after DROP temp tables

connection master;

create table t1(f int);

insert into t1 values (1);



sync_slave_with_master;

#connection slave;

select * from t1 /* must be 1 */;



connection master; 

drop table t1;



# End of 4.1 tests

sql/sql_base.cc

+121 −40
Original line number Diff line number Diff line
@@ -483,13 +483,23 @@ void close_temporary(TABLE *table,bool delete_table) 
  DBUG_VOID_RETURN;

}



/* close_temporary_tables' internal */

static inline uint  tmpkeyval(THD *thd, TABLE *table)

{

  return uint4korr(table->table_cache_key + table->key_length - 

                   sizeof(thd->variables.pseudo_thread_id));

}



/* Creates one DROP TEMPORARY TABLE binlog event for each pseudo-thread */



void close_temporary_tables(THD *thd)

{

  TABLE *table,*next;

  char *query, *end;

  uint query_buf_size; 

  bool found_user_tables = 0;

  TABLE *next,

    *prev_table /* prev link is not maintained in TABLE's double-linked list */,

    *table;

  char *query= (gptr) 0, *end;

  uint query_buf_size, max_names_len; 

  bool found_user_tables;



  if (!thd->temporary_tables)

    return;
@@ -497,40 +507,105 @@ void close_temporary_tables(THD *thd) 
  LINT_INIT(end);

  query_buf_size= 50;   // Enough for DROP ... TABLE IF EXISTS



  for (table=thd->temporary_tables ; table ; table=table->next)

  /* 

      We are going to add 4 ` around the db/table names, so 1 does not look

     insertion sort of temp tables by pseudo_thread_id to build ordered list 

     of sublists of equal pseudo_thread_id

  */

  for (prev_table= thd->temporary_tables, 

         table= prev_table->next,

         found_user_tables= (prev_table->table_name[0] != '#'); 

       table;

       prev_table= table, table= table->next)

  {

    TABLE *prev_sorted /* same as for prev_table */,

      *sorted;

    /*

      table not created directly by the user is moved to the tail. 

      Fixme/todo: nothing (I checked the manual) prevents user to create temp

      with `#' 

    */

    if (table->real_name[0] == '#')

      continue;

    else 

    {

      found_user_tables = 1;

    }

    for (prev_sorted= NULL, sorted= thd->temporary_tables; sorted != table; 

         prev_sorted= sorted, sorted= sorted->next)

    {

      if (sorted->real_name[0] == '#' || tmpkeyval(thd, sorted) > tmpkeyval(thd, table))

      {

        /* move into the sorted part of the list from the unsorted */

        prev_table->next= table->next;

        table->next= sorted;

        if (prev_sorted) 

        {

          prev_sorted->next= table;

        }

        else

        {

          thd->temporary_tables= table;

        }

        table= prev_table;

        break;

      }

    }

  }  

  /* 

     calc query_buf_size as max per sublists, one sublist per pseudo thread id.

     Also stop at first occurence of `#'-named table that starts 

     all implicitly created temp tables

  */

  for (max_names_len= 0, table=thd->temporary_tables; 

       table && table->real_name[0] != '#';

       table=table->next)

  {

    uint tmp_names_len;

    for (tmp_names_len= table->key_length + 1;

         table->next && table->real_name[0] != '#' &&

           tmpkeyval(thd, table) == tmpkeyval(thd, table->next);

         table=table->next)

    {

      /*

        We are going to add 4 ` around the db/table names, so 1 might not look

        enough; indeed it is enough, because table->key_length is greater (by 8,

        because of server_id and thread_id) than db||table.

      */

    query_buf_size+= table->key_length+1;

      tmp_names_len += table->next->key_length + 1;

    }

    if (tmp_names_len > max_names_len) max_names_len= tmp_names_len;

  }

  

  if ((query = alloc_root(thd->mem_root, query_buf_size)))

  /* allocate */

  if (found_user_tables && mysql_bin_log.is_open() &&

      (query = alloc_root(thd->mem_root, query_buf_size+= max_names_len)))

    // Better add "if exists", in case a RESET MASTER has been done

    end= strmov(query, "DROP /*!40005 TEMPORARY */ TABLE IF EXISTS ");



  /* scan sorted tmps to generate sequence of DROP */

  for (table=thd->temporary_tables; table; table= next)

  {

    if (query) // we might be out of memory, but this is not fatal

    if (query // we might be out of memory, but this is not fatal 

        && table->real_name[0] != '#') 

    {

      // skip temporary tables not created directly by the user

      if (table->real_name[0] != '#')

	found_user_tables = 1;

      /*

        Here we assume table_cache_key always starts

        with \0 terminated db name

      */

      end = strxmov(end,"`",table->table_cache_key,"`.`",

      char *end_cur;

      /* Set pseudo_thread_id to be that of the processed table */

      thd->variables.pseudo_thread_id= tmpkeyval(thd, table);

      /* Loop forward through all tables within the sublist of

         common pseudo_thread_id to create single DROP query */

      for (end_cur= end;

           table && table->real_name[0] != '#' &&

             tmpkeyval(thd, table) == thd->variables.pseudo_thread_id;

           table= next)

      {

        end_cur= strxmov(end_cur, "`", table->table_cache_key, "`.`",

                      table->real_name, "`,", NullS);

    }

        next= table->next;

    close_temporary(table);

        close_temporary(table, 1);

      }

  if (query && found_user_tables && mysql_bin_log.is_open())

  {

    /* The -1 is to remove last ',' */

      thd->clear_error();

    Query_log_event qinfo(thd, query, (ulong)(end-query)-1, 0, FALSE);

      /* The -1 is to remove last ',' */

      Query_log_event qinfo(thd, query, (ulong)(end_cur - query) - 1, 0, FALSE);

      /*

        Imagine the thread had created a temp table, then was doing a SELECT, and

        the SELECT was killed. Then it's not clever to mark the statement above as
@@ -543,6 +618,12 @@ void close_temporary_tables(THD *thd) 
      qinfo.error_code= 0;

      mysql_bin_log.write(&qinfo);

    }

    else 

    {

      next= table->next;

      close_temporary(table, 1);

    }

  }

  thd->temporary_tables=0;

}