Hi, Alexander!
On Jun 15, Alexander Barkov wrote:
(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?
yes, I believe delimiters are pretty much ignored in our code. so any
delimiter can be used anywhere.
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?
The way it works now - after your patch - there's no much need for a
"preference" flag. The only issue I've uncovered in testing was related
to parsing strings with time preference. Like in
WHERE time_column > '2010-12-11'
The code is
my_bool str_to_time(const char *str, uint length, MYSQL_TIME *l_time,
ulonglong fuzzydate, MYSQL_TIME_STATUS *status)
{
...
/* Check first if this is a full TIMESTAMP */
if (length >= 12)
{ /* Probably full timestamp */
(void) str_to_datetime(str, length, l_time,
(fuzzydate & ~TIME_TIME_ONLY) | TIME_DATETIME_ONLY,
status);
Which is very stupid, it decides solely on the string length. That is
'2010-12-11' is parsed as a time (when there's time preference), but
'10:11:12.123456' is parsed as a date (but fails and falls back to
time).
I would suggest to get rid of this ad hoc detection code (check the
length, try and fall back, etc). And use a systematic approach based on
patterns. Like
patterns[]=
{
{ 'yyyy-mm-dd' , parse_date },
{ 'hh:mm:ss.uuuuuu', parse_time },
...
}
Note, I wrote "like". I do not mean literally these patterns or string
patterns whatsoever. I'd prefer something much faster. May be some
compact "signature" number that describes the format, or may be a
decision tree (where the string is parsed into an array of ints and then
analyzed like three numbers? first is 4 digit? etc).
Regards,
Sergei
