RE: pg_upgrade: Pass -j down to vacuumdb

On January 29, 2019 8:19 PM +0000, Jesper Pedersen wrote:
>On 1/29/19 12:08 AM, Michael Paquier wrote:
>> I would document the optional VACUUM_OPTS on the page of pg_upgrade.
>> If Peter thinks it is fine to not do so, that's fine for me as well.
>>
..
>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.

>> 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?

Regards,
Kirk Jamison