Tom Lane wrote:
The fly in the ointment is that after collecting the pg_index definition
of the index, plancat.c also wants to know how big it is --- it calls
RelationGetNumberOfBlocks. And that absolutely does look at the
physical storage, which means it absolutely is unsafe to do in parallel
with a REINDEX that will be dropping the old physical storage at some
point.
So maybe we are stuck and we have to say "that doesn't work anymore".
But it feels like we might not be too far away from letting it still
work. Thoughts, ideas?
A suggestion that seems a bit like a leap backwards in time - maybe just
use the pg_class.relpages entry for the index size?
I'm punting that with autovacuum being enabled by default now, the
relpages entries for all relations will be more representative than they
used to in previous releases.
Cheers
Mark
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
