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Bug#12809202 61854: MYSQLDUMP --SINGLE-TRANSACTION

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--FLUSH-LOG BREAKS CONSISTENCY

The transaction started by mysqldump gets committed
implicitly when flush-log is specified along with
single-transaction option, and hence can break
consistency.

This is because, COM_REFRESH is executed in order
to flush logs and starting from 5.5 this command
performs an implicit commit.

Fixed by making sure that COM_REFRESH is executed
before the transaction has started and not after it.

Note : This patch triggers following behavioral
       changes in mysqldump :

1) After this patch we no longer flush logs before
   dumping each database if --single-transaction
   option is given like it was done before (in the
   absence of --lock-all-tables and --master-data
   options).

2) Also, after this patch, we start acquiring
   FTWRL before flushing logs in cases when only
   --single-transaction and --flush-logs are given.
   It becomes safe to use mysqldump with these two
   options and without --master-data parameter for
   backups.
This commit is contained in:
Nirbhay Choubey
2011-12-23 23:05:00 +05:30
parent 74a8331c08
commit a4343d56ed
3 changed files with 164 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

42
client/mysqldump.c
View File

@ -4079,6 +4079,8 @@ static int dump_all_tables_in_db(char *database)
if (mysql_refresh(mysql, REFRESH_LOG))
DB_error(mysql, "when doing refresh");
/* We shall continue here, if --force was given */
else
verbose_msg("-- dump_all_tables_in_db : logs flushed successfully!\n");
}
while ((table= getTableName(0)))
{
@ -4179,6 +4181,8 @@ static my_bool dump_all_views_in_db(char *database)
if (mysql_refresh(mysql, REFRESH_LOG))
DB_error(mysql, "when doing refresh");
/* We shall continue here, if --force was given */
else
verbose_msg("-- dump_all_views_in_db : logs flushed successfully!\n");
}
while ((table= getTableName(0)))
{
@ -4317,6 +4321,8 @@ static int dump_selected_tables(char *db, char **table_names, int tables)
DB_error(mysql, "when doing refresh");
}
/* We shall countinue here, if --force was given */
else
verbose_msg("-- dump_selected_tables : logs flushed successfully!\n");
}
if (opt_xml)
print_xml_tag(md_result_file, "", "\n", "database", "name=", db, NullS);
@ -4600,6 +4606,7 @@ static int purge_bin_logs_to(MYSQL *mysql_con, char* log_name)
static int start_transaction(MYSQL *mysql_con)
{
verbose_msg("-- Starting transaction...\n");
/*
We use BEGIN for old servers. --single-transaction --master-data will fail
on old servers, but that's ok as it was already silently broken (it didn't
@ -5199,24 +5206,39 @@ int main(int argc, char **argv)
if (opt_slave_data && do_stop_slave_sql(mysql))
goto err;
if ((opt_lock_all_tables || opt_master_data) &&
if ((opt_lock_all_tables || opt_master_data ||
(opt_single_transaction && flush_logs)) &&
do_flush_tables_read_lock(mysql))
goto err;
if (opt_single_transaction && start_transaction(mysql))
goto err;
if (opt_delete_master_logs)
/*
Flush logs before starting transaction since
this causes implicit commit starting mysql-5.5.
*/
if (opt_lock_all_tables || opt_master_data ||
(opt_single_transaction && flush_logs) ||
opt_delete_master_logs)
{
if (mysql_refresh(mysql, REFRESH_LOG) ||
get_bin_log_name(mysql, bin_log_name, sizeof(bin_log_name)))
goto err;
if (flush_logs || opt_delete_master_logs)
{
if (mysql_refresh(mysql, REFRESH_LOG))
goto err;
verbose_msg("-- main : logs flushed successfully!\n");
}
/* Not anymore! That would not be sensible. */
flush_logs= 0;
}
if (opt_lock_all_tables || opt_master_data)
if (opt_delete_master_logs)
{
if (flush_logs && mysql_refresh(mysql, REFRESH_LOG))
if (get_bin_log_name(mysql, bin_log_name, sizeof(bin_log_name)))
goto err;
flush_logs= 0; /* not anymore; that would not be sensible */
}
if (opt_single_transaction && start_transaction(mysql))
goto err;
/* Add 'STOP SLAVE to beginning of dump */
if (opt_slave_apply && add_stop_slave())
goto err;