Re: [HACKERS] Fixing pgbench's logging of transaction timestamps - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [HACKERS] Fixing pgbench's logging of transaction timestamps
Date
Msg-id 18059.1483302133@sss.pgh.pa.us
Whole thread Raw
In response to Re: [HACKERS] Fixing pgbench's logging of transaction timestamps  (Fabien COELHO <coelho@cri.ensmp.fr>)
Responses Re: [HACKERS] Fixing pgbench's logging of transaction timestamps  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Fabien COELHO <coelho@cri.ensmp.fr> writes:
>> 3. Forget about using the instr_time result and just have doLog() execute
>> gettimeofday() to obtain the timestamp to print.  This is kind of
>> conceptually ugly, but realistically the added overhead is probably
>> insignificant.  A larger objection might be that on Windows, the result
>> of gettimeofday() isn't very high precision ... but it'd still be a huge
>> improvement over the non-answer you get now.

> Yep.

>> I'm inclined to think that #2 isn't a very good choice; it appears to
>> preserve the current behavior but really doesn't.  So we should either
>> change the behavior as in #1 or expend an extra system call as in #3.
>> Preferences?

> Marginal preference for #3 for KIS? Otherwise any three options seems 
> better than the current status.

OK, done that way.

BTW, why is it that the --aggregate-interval option is unsupported on
Windows?  Is that an artifact of the same disease of assuming too much
about how instr_time is represented?  I don't see any very good reason
for it other than the weird decision to store the result of
INSTR_TIME_GET_DOUBLE in a "long", which seems rather broken in any case.
        regards, tom lane



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