Re: pg_upgrade: Pass -j down to vacuumdb

Hi,

On 1/30/19 7:59 PM, Jamison, Kirk wrote:
>> I added most of the documentation back, as requested by Kirk.
>
> Actually, I find it useful to be documented. However, major contributors have higher opinions in terms of experience, so I think it's alright with me not to include the doc part if they finally say so.
>

I think we need to leave it to the Committer to decide, as both Peter
and Michael are committers; provided the patch reaches RfC.

>>> It seems to me that the latest patch sent is incorrect for multiple
>>> reasons:
>>> 1) You still enforce -j to use the number of jobs that the caller of
>>> pg_upgrade provides, and we agreed that both things are separate
>>> concepts upthread, no? What has been suggested by Alvaro is to add a
>>> comment so as one can use VACUUM_OPTS with -j optionally, instead of
>>> suggesting a full-fledged vacuumdb command which depends on what
>>> pg_upgrade uses. So there is no actual need for the if/else
>>> complication business.
>
>> I think it is ok for the echo command to highlight to the user that running --analyze-only using the same amount of jobs will give a faster result.
>
> I missed that part.
> IIUC, using the $VACUUMDB_OPTS variable would simplify and correct the usage of jobs for vacuumdb. (pg_upgrade jobs is not equal to vacuumdb jobs) Plus, it might simplify and reduce the number of additional lines.
> Tom Lane also suggested above to make the script absorb the value from env.
> Would that address your concern of getting a faster result, yes?
>

The actual line in the script executed is using $VACUUMDB_OPTS at the
moment, so could you expand on the above ? The 'if' could be removed if
we assume that pg_upgrade would only be used with server > 9.5, but to
be safer I would leave it in, as it is only console output.

Best regards,
Jesper