1
0
mirror of https://github.com/MariaDB/server.git synced 2025-08-01 03:47:19 +03:00

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.
This commit is contained in:
aelkin@mysql.com
2006-04-23 12:18:57 +03:00
parent 50e8e58c8a
commit a4ff312037
3 changed files with 167 additions and 46 deletions

View File

@ -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;
@ -497,51 +507,122 @@ 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
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;
if ((query = alloc_root(thd->mem_root, query_buf_size)))
// Better add "if exists", in case a RESET MASTER has been done
end=strmov(query, "DROP /*!40005 TEMPORARY */ TABLE IF EXISTS ");
for (table=thd->temporary_tables ; table ; table=next)
/*
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)
{
if (query) // we might be out of memory, but this is not fatal
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
{
// 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,"`.`",
table->real_name,"`,", NullS);
found_user_tables = 1;
}
next=table->next;
close_temporary(table);
}
if (query && found_user_tables && mysql_bin_log.is_open())
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)
{
/* The -1 is to remove last ',' */
thd->clear_error();
Query_log_event qinfo(thd, query, (ulong)(end-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
"killed", because it's not really a statement updating data, and there
are 99.99% chances it will succeed on slave.
If a real update (one updating a persistent table) was killed on the
master, then this real update will be logged with error_code=killed,
rightfully causing the slave to stop.
*/
qinfo.error_code= 0;
mysql_bin_log.write(&qinfo);
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.
*/
tmp_names_len += table->next->key_length + 1;
}
if (tmp_names_len > max_names_len) max_names_len= tmp_names_len;
}
/* 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
&& table->real_name[0] != '#')
{
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, 1);
}
thd->clear_error();
/* 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
"killed", because it's not really a statement updating data, and there
are 99.99% chances it will succeed on slave.
If a real update (one updating a persistent table) was killed on the
master, then this real update will be logged with error_code=killed,
rightfully causing the slave to stop.
*/
qinfo.error_code= 0;
mysql_bin_log.write(&qinfo);
}
else
{
next= table->next;
close_temporary(table, 1);
}
}
thd->temporary_tables=0;
}