On 02/01/2019 20:47, Jesper Pedersen wrote: > Well, that really depends. The user passed -j to pg_upgrade in order for > the upgrade to happen faster, so maybe they would expect, as I would, > that the ANALYZE phase would happen in parallel too.
pg_upgrade -j reduces the *downtime* caused by pg_upgrade during the upgrade process. Also, during said downtime, nothing else is happening, so you can use all the resources of the machine. Once the system is back up, you don't necessarily want to use all the resources. The analyze script is specifically written to run while production traffic is active. If you just want to run the analyze as fast as possible, you can just run vacuumdb -j directly, without using the script. Moreover, it's not clear that pg_upgrade and vacuumdb are bound the same way, so it's not a given that the same -j number should be used. Perhaps more documentation would be useful here. -- Peter Eisentraut http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
