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Thread: Confirming \timing output

Confirming \timing output

From
"Gauthier, Dave"
Date:

With \timing set on, I run an update statement and it reports....

 

Time: 0.524 ms

 

Is that really 0.524 ms?  As in 524 nanoseconds?

 

Also, is this wallclock time or some sort of indication of how much cpu it took?

 

Thanks for any answers !

 

Re: Confirming \timing output

From
Steven Schlansker
Date:
On Aug 23, 2012, at 11:13 AM, "Gauthier, Dave" <dave.gauthier@intel.com> wrote:

> With \timing set on, I run an update statement and it reports....
>
> Time: 0.524 ms
>
> Is that really 0.524 ms?  As in 524 nanoseconds?

0.524ms = 524000ns

Perhaps you meant microseconds?

0.524ms = 524us

If all your data happens to be in RAM cache, simple queries can execute very fast!  Unless you have a reason to believe
it'swrong, I would trust it to be accurate :-) 

>
> Also, is this wallclock time or some sort of indication of how much cpu it took?
>
> Thanks for any answers !
>


\timing measures wall time.  There's a more detailed discussion of the difference between this and e.g. EXPLAIN ANALYZE
here:

http://postgresql.1045698.n5.nabble.com/What-does-timing-measure-td4289329.html

Re: Confirming \timing output

From
John R Pierce
Date:
On 08/23/12 11:13 AM, Gauthier, Dave wrote:
>
> Time: 0.524 ms
>
> Is that really 0.524 ms?  As in 524 nanoseconds?
>

0.524 MILLIseconds.  as in 524 microseconds.   microseconds is commonly
abbreviated us.

afaik, its elapsed time, not CPU time.

--
john r pierce                            N 37, W 122
santa cruz ca                         mid-left coast

Re: Confirming \timing output

From
Craig Ringer
Date:
On 08/24/2012 02:30 AM, John R Pierce wrote:
> On 08/23/12 11:13 AM, Gauthier, Dave wrote:
>>
>> Time: 0.524 ms
>>
>> Is that really 0.524 ms?  As in 524 nanoseconds?
>>
>
> 0.524 MILLIseconds.  as in 524 microseconds.   microseconds is commonly
> abbreviated us.

They should be µs ; (micro µ seconds s). Sadly, many setups still can't
type anything outside 7-bit ASCII even in 2012 :-(

--
Craig Ringer

Re: Confirming \timing output

From
John R Pierce
Date:
On 08/23/12 7:31 PM, Craig Ringer wrote:
>>>
>>
>> 0.524 MILLIseconds.  as in 524 microseconds.   microseconds is commonly
>> abbreviated us.
>
> They should be µs ; (micro µ seconds s). Sadly, many setups still
> can't type anything outside 7-bit ASCII even in 2012

yeah, I know I could enter the alt+xyz except this laptop keyboard
doesn't have a number pad, and I was way way too lazy to find and
copy/paste one, or to use charmap.

--
john r pierce                            N 37, W 122
santa cruz ca                         mid-left coast