Hi, Vladislav!
On Jun 08, Vladislav Vaintroub wrote:
> ------------------------------------------------------------
> revno: 3426
> revision-id: [email protected]
> parent: [email protected]
> fixes bug(s): https://launchpad.net/bugs/1008334
> committer: Vladislav Vaintroub <[email protected]>
> branch nick: 5.5
> timestamp: Fri 2012-06-08 02:08:41 +0200
> message:
> LP1008334 : Speedup specific datetime queries that got slower with
> introduction of microseconds
>
> - Item::get_seconds() now skips decimal arithmetic, if decimals is 0. This
> significantly speeds up from_unixtime() if no fractional part is passed.
> - replace sprintfs used to format temporal values by hand-coded formatting
Looks ok.
Would be good to mention the ~25% speedup in the comment above
fmt_number. Like "Gives 25% speedup when converting temporal values to
strings, as compared to sprintf".
So that one wouldn't need to dig up bzr history every time.
> === modified file 'sql/item.cc'
> --- a/sql/item.cc 2012-05-21 18:54:41 +0000
> +++ b/sql/item.cc 2012-06-08 00:08:41 +0000
> @@ -1265,7 +1265,7 @@
>
> bool Item::get_seconds(ulonglong *sec, ulong *sec_part)
> {
> - if (result_type() == INT_RESULT)
> + if (decimals == 0 || result_type() == INT_RESULT)
I'd expect that checking for decimals==0 alone should be enough.
Could you try to run the test suite with the
DBUG_ASSERT(result_type() != INT_RESULT || decimals == 0);
please?
> { // optimize for an important special case
> longlong val= val_int();
> bool neg= val < 0 && !unsigned_flag;
Regards,
Sergei
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