Re: pg_dump - how to force to show timestamps in client log - Mailing list pgsql-general

From Adrian Klaver
Subject Re: pg_dump - how to force to show timestamps in client log
Date
Msg-id 96a0c112-0ecd-ebe1-fba3-604ab25276bd@aklaver.com
Whole thread Raw
In response to Re: pg_dump - how to force to show timestamps in client log  (Ron <ronljohnsonjr@gmail.com>)
Responses Re: pg_dump - how to force to show timestamps in client log  (Ron <ronljohnsonjr@gmail.com>)
List pgsql-general
On 11/20/20 1:00 PM, Ron wrote:
> On 11/20/20 2:56 PM, Adrian Klaver wrote:
>> On 11/20/20 10:01 AM, Durumdara wrote:
>>> Hello!
>>>
>>> We need to log the pg_dump's state.
>>> What objects are in copy, and what are the starting and ending times.
>>>
>>> But when I try to redirect the output, the result doesn't have 
>>> timestamps.
>>>
>>> PG 11, on Windows.
>>>
>>> As I see the -v option isn't enough to see the starting times.
>>>
>>> For example:
>>>
>>> 2020-11-19 12:00:01.084 Dump table content table1
>>> 2020-11-19 12:03:12.932 Dump table content table2
>>> ...
>>> etc.
>>
>>
>> If you are redirecting to a file it have the creation time that you 
>> can use. Internally times don't really matter for the objects as the 
>> dump is based on a snapshot. Said snapshot is based on visible 
>> transactions not time. So for practical purposes they all occur at the 
>> same 'time'.
> 
> It makes all the difference when monitoring the progress of a backup.
> 

With -v you will get running list of objects dumped, just not the time. 
The time is only of value relative to the following. Progress will only 
be measurable by determining what is left to run and the time for each 
object. Not sure that is feasible as you would have to pre-run the dump 
to get information about the number of objects and an estimate of the 
data quantity involved and the effect of each on the other. I could see 
that estimate getting worse the bigger the data set(and hence the more 
you cared) got. Because at some point the load on the machine would 
affect the output speed of the dump.


-- 
Adrian Klaver
adrian.klaver@aklaver.com



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