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Bug #27571 asynchronousity in setting mysql_query::error and

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Query_log_event::error_code

A query can perform completely having the local var error of mysql_$query
zero, where $query in insert, update, delete, load,
and be  binlogged with error_code e.g KILLED_QUERY while there is no
reason do to so.
That can happen because Query_log_event consults thd->killed flag to
evaluate error_code.

Fixed with implementing a scheme suggested and partly implemented at
time of bug@22725 work-on. error_status is cached immediatly after the
control leaves the main rows-loop and that instance always corresponds
to `error' the local of mysql_$query functions. The cached value
is passed to Query_log_event constructor, not the default thd->killed
which can be changed in between of the caching and the constructing.
This commit is contained in:
aelkin/elkin@koti.dsl.inet.fi
2007-10-29 15:20:59 +02:00
parent ed0ab76e28
commit 27436f0ba3
12 changed files with 509 additions and 203 deletions
Download Patch File Download Diff File Expand all files Collapse all files

70
sql/sql_update.cc
View File

@ -134,6 +134,7 @@ int mysql_update(THD *thd,
SELECT_LEX *select_lex= &thd->lex->select_lex;
bool need_reopen;
List<Item> all_fields;
THD::killed_state killed_status= THD::NOT_KILLED;
DBUG_ENTER("mysql_update");
LINT_INIT(timestamp_query_id);
@ -519,43 +520,26 @@ int mysql_update(THD *thd,
table->file->unlock_row();
thd->row_count++;
}
/*
Caching the killed status to pass as the arg to query event constuctor;
The cached value can not change whereas the killed status can
(externally) since this point and change of the latter won't affect
binlogging.
It's assumed that if an error was set in combination with an effective
killed status then the error is due to killing.
*/
killed_status= thd->killed; // get the status of the volatile
// simulated killing after the loop must be ineffective for binlogging
DBUG_EXECUTE_IF("simulate_kill_bug27571",
{
thd->killed= THD::KILL_QUERY;
};);
error= (killed_status == THD::NOT_KILLED)? error : 1;
if (!transactional_table && updated > 0)
thd->transaction.stmt.modified_non_trans_table= TRUE;
/*
todo bug#27571: to avoid asynchronization of `error' and
`error_code' of binlog event constructor
The concept, which is a bit different for insert(!), is to
replace `error' assignment with the following lines
killed_status= thd->killed; // get the status of the volatile
Notice: thd->killed is type of "state" whereas the lhs has
"status" the suffix which translates according to WordNet: a state
at a particular time - at the time of the end of per-row loop in
our case. Binlogging ops are conducted with the status.
error= (killed_status == THD::NOT_KILLED)? error : 1;
which applies to most mysql_$query functions.
Event's constructor will accept `killed_status' as an argument:
Query_log_event qinfo(..., killed_status);
thd->killed might be changed after killed_status had got cached and this
won't affect binlogging event but other effects remain.
Open issue: In a case the error happened not because of KILLED -
and then KILLED was caught later still within the loop - we shall
do something to avoid binlogging of incorrect ER_SERVER_SHUTDOWN
error_code.
*/
if (thd->killed && !error)
error= 1; // Aborted
end_read_record(&info);
free_io_cache(table); // If ORDER BY
delete select;
@ -587,7 +571,7 @@ int mysql_update(THD *thd,
if (error < 0)
thd->clear_error();
Query_log_event qinfo(thd, thd->query, thd->query_length,
transactional_table, FALSE);
transactional_table, FALSE, killed_status);
if (mysql_bin_log.write(&qinfo) && transactional_table)
error=1; // Rollback update
}
@ -1522,6 +1506,11 @@ void multi_update::send_error(uint errcode,const char *err)
*/
if (mysql_bin_log.is_open())
{
/*
THD::killed status might not have been set ON at time of an error
got caught and if happens later the killed error is written
into repl event.
*/
Query_log_event qinfo(thd, thd->query, thd->query_length,
transactional_tables, FALSE);
mysql_bin_log.write(&qinfo);
@ -1709,10 +1698,19 @@ err2:
bool multi_update::send_eof()
{
char buff[STRING_BUFFER_USUAL_SIZE];
THD::killed_state killed_status= THD::NOT_KILLED;
thd->proc_info="updating reference tables";
/* Does updates for the last n - 1 tables, returns 0 if ok */
/*
Does updates for the last n - 1 tables, returns 0 if ok;
error takes into account killed status gained in do_updates()
*/
int local_error = (table_count) ? do_updates(0) : 0;
/*
if local_error is not set ON until after do_updates() then
later carried out killing should not affect binlogging.
*/
killed_status= (local_error == 0)? THD::NOT_KILLED : thd->killed;
thd->proc_info= "end";
/* We must invalidate the query cache before binlog writing and
@ -1740,7 +1738,7 @@ bool multi_update::send_eof()
if (local_error == 0)
thd->clear_error();
Query_log_event qinfo(thd, thd->query, thd->query_length,
transactional_tables, FALSE);
transactional_tables, FALSE, killed_status);
if (mysql_bin_log.write(&qinfo) && trans_safe)
local_error= 1; // Rollback update
}