Tom Lane schrieb:
Marinos Yannikos <mjy@xxxxxxxxxxx> writes:
"i_a" btree (a)
"i_ab" btree (a, b)
I suspect that these indexes are exactly the same size --- look at
pg_class.relpages or use the pg_relation_size() function to verify.
For some reason, the first one is actually about twice the size of the
second (175458 relpages vs. 88186, pg_relation_size() confirms it).
It wouldn't
really matter anyway because the actual runtime should be pretty
much the same too.
The runtime is unfortunately worse in some cases due to the degradation
we've been seeing (lots of INSERT/UPDATE on this table), but I think we
fixed this with nightly REINDEX runs on the 2-dimensional indexes (which
is probably also the reason for the odd sizes above). I guess we can
just drop the first index then.
Thanks,
-mjy
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