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BUG#16290902 DROP TEMP TABLE IF EXISTS CAN CAUSE POINT

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IN TIME RECOVERY FAILURE ON SLAVES

Problem:
DROP TEMP TABLE IF EXISTS commands can cause point
in time recovery (re-applying binlog) failures.

Analyses:
In RBR, 'DROP TEMPORARY TABLE' commands are
always binlogged by adding 'IF EXISTS' clauses.
Also, the slave SQL thread will not check replicate.* filter
rules for "DROP TEMPORARY TABLE IF EXISTS" queries.
If log-slave-updates is enabled on slave, these queries
will be binlogged in the format of "USE `db`;
DROP TEMPORARY TABLE IF EXISTS `t1`;" irrespective
of filtering rules and irrespective of the `db` existence.
When users try to recover slave from it's own binlog,
use `db` command might fail if `db` is not present on slave.

Fix:
At the time of writing the 'DROP TEMPORARY TABLE
IF EXISTS' query into the binlog, 'use `db`' will not be
present and the table name in the query will be a fully
qualified table name.
Eg:
'USE `db`; DROP TEMPORARY TABLE IF EXISTS `t1`;'
will be logged as
'DROP TEMPORARY TABLE IF EXISTS `db`.`t1`;'.
This commit is contained in:
Venkatesh Duggirala
2013-07-27 17:35:02 +05:30
parent b89e6ccfc4
commit eb152f86af
21 changed files with 280 additions and 263 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
sql/sql_table.cc
View File

@ -2001,6 +2001,7 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
bool non_tmp_error= 0;
bool trans_tmp_table_deleted= 0, non_trans_tmp_table_deleted= 0;
bool non_tmp_table_deleted= 0;
bool is_drop_tmp_if_exists_added= 0;
String built_query;
String built_trans_tmp_query, built_non_trans_tmp_query;
DBUG_ENTER("mysql_rm_table_no_locks");
@ -2029,6 +2030,15 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
table stems from the fact that such drop does not commit an ongoing
transaction and changes to non-transactional tables must be written
ahead of the transaction in some circumstances.
6- Slave SQL thread ignores all replicate-* filter rules
for temporary tables with 'IF EXISTS' clause. (See sql/sql_parse.cc:
mysql_execute_command() for details). These commands will be binlogged
as they are, even if the default database (from USE `db`) is not present
on the Slave. This can cause point in time recovery failures later
when user uses the slave's binlog to re-apply. Hence at the time of binary
logging, these commands will be written with fully qualified table names
and use `db` will be suppressed.
*/
if (!dont_log_query)
{
@ -2043,6 +2053,7 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
if (thd->is_current_stmt_binlog_format_row() || if_exists)
{
is_drop_tmp_if_exists_added= true;
built_trans_tmp_query.set_charset(system_charset_info);
built_trans_tmp_query.append("DROP TEMPORARY TABLE IF EXISTS ");
built_non_trans_tmp_query.set_charset(system_charset_info);
@ -2120,10 +2131,12 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
String *built_ptr_query=
(is_trans ? &built_trans_tmp_query : &built_non_trans_tmp_query);
/*
Don't write the database name if it is the current one (or if
thd->db is NULL).
Write the database name if it is not the current one or if
thd->db is NULL or 'IF EXISTS' clause is present in 'DROP TEMPORARY'
query.
*/
if (thd->db == NULL || strcmp(db,thd->db) != 0)
if (thd->db == NULL || strcmp(db,thd->db) != 0
|| is_drop_tmp_if_exists_added )
{
append_identifier(thd, built_ptr_query, db, db_len);
built_ptr_query->append(".");
@ -2317,7 +2330,9 @@ err:
error |= thd->binlog_query(THD::STMT_QUERY_TYPE,
built_non_trans_tmp_query.ptr(),
built_non_trans_tmp_query.length(),
FALSE, FALSE, FALSE, 0);
FALSE, FALSE,
is_drop_tmp_if_exists_added,
0);
}
if (trans_tmp_table_deleted)
{
@ -2327,7 +2342,9 @@ err:
error |= thd->binlog_query(THD::STMT_QUERY_TYPE,
built_trans_tmp_query.ptr(),
built_trans_tmp_query.length(),
TRUE, FALSE, FALSE, 0);
TRUE, FALSE,
is_drop_tmp_if_exists_added,
0);
}
if (non_tmp_table_deleted)
{