If I read the code correctly, the VACUUM PARALLEL option is capped by
the active max_parallel_maintenance_workers setting. So if I write
VACUUM (PARALLEL 5), it will still only do 2 by default. Is that
correct? The documentation (VACUUM man page) seems to indicate a
different behavior.
I haven't been able to set up something to test or verify this either way.
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Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services