This is related to progress reporting for ANALYZE and partitioned
tables.

Author: Amit Langote
Reviewed-by: Daniel Gustafsson, Julien Rouhaud
Discussion: https://postgr.es/m/CA+HiwqGx6C=-bFTX=ryMThyvM7CcSC3b1x8_6zh4Uo41Kvu-zw@mail.gmail.com