Hi Sergei, On 06/12/2015 01:00 PM, Sergei Golubchik wrote:
Hi, Alexander!
On Jun 11, Alexander Barkov wrote:
The problem is in this piece of the code:
if (args[0]->get_time(&l_time1) || args[1]->get_time(&l_time2) || l_time1.time_type != l_time2.time_type) return (null_value= 1);
get_time() forces decimal-to-time conversion to truncate the date part and return MYSQL_TIMESTAMP_TIME.
get_time() does not force string-to-time conversion to truncate the date part. It still returns the full MYSQL_TIMESTAMP_DATETIME.
I'm afraid a lot of the code rely in this behavior. If we fix string-to-time conversion, mtr will start to fail in other cases.
First, this is clearly a bug that get_time behaves differently for numbers and strings. One could get different results for
WHERE time_column = 'string'
and
WHERE time_column = number
Something needs to be fixed. We cannot fix string-to-time conversion to return MYSQL_TIMESTAMP_TIME in all cases. When a string literal is parsed we don't always know in advance whether it's a datetime or a time, so we can only indicate *preference* based on the context (preference matters, as it tells how to parse ambiguous strings like "10:10:10").
I'd say '10:10:10' should be unambiguously treated as time. Colon is never used to delimit date parts. Is it? Date parts are usually delimited by as follows: '01-01-01' '01.01.01' '01/01/01' But this is a kind of separate issue. Would you like me to create a task for this? In other cases it could still use the *preference* flag: '01#01#01' - could be either date or time, depending on the flag.
So, I've fixed number_to_time to keep the date part:
For some reasons I even didn't consider fixing number_to_time() as an option. Thanks. This fixes the bug. I pushed this change with a test added.
--- a/sql-common/my_time.c +++ b/sql-common/my_time.c @@ -1319,9 +1319,6 @@ int number_to_time(my_bool neg, ulonglong nr, ulong sec_pa TIME_INVALID_DATES, was_cut) < 0) return -1;
- ltime->year= ltime->month= ltime->day= 0; - ltime->time_type= MYSQL_TIMESTAMP_TIME; - *was_cut= MYSQL_TIME_NOTE_TRUNCATED; return 0; }
The only test that changed results was type_time_hires, and I think the change was ok.
Regards, Sergei