Hello Basexers,
I'm getting such a low performance on a relatively simple join between two
databases that I feel there must be something going wrong here. I can provide
the sources if necessary, but basically DB1 is 26 MB, about 80,000 small
documents; DB2 is 47 MB, about 18,500 small documents. I'm using 8.4, by the
way, haven't tested on other releases.
Query 1 [returns in 144 minutes]
----------------------------------------
for $a in (db:open('DB1')/item/order-id)
return
if (db:open('DB2')//order-id[. = $a]) then
$a
else
()
Note that the optimized query uses db:open-pre to access DB2. When I re-write
the query myself to use the TEXT index then performance is excellent. But why
such a difference?
Query 2 [returns in 0.3 second]
----------------------------------------
for $a in (db:open('DB1')/item/order-id)
return
if (db:text('DB2', $a)/parent::order-id) then
$a
else
()
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