On Oct 20, 2007, at 12:19 PM, Andreas Kretschmer wrote:
Markus Schaber <schabi@xxxxxxxxxxxx> schrieb:
is there any way to get both results in a single query,
eventually through stored procedure?
The retrieved [count(*),A] ; [count(*),B)] data couldnt fit
on a single table, of course.
The main goal would be to get multiple results while scanning the
table[s] once only
thus getting results in a faster way.
PostgreSQL 8.3 contains great improvements in this area, you can
simply
start the selects from concurrent connections, and the backend will
synchronize the scans.
works this right across different transactions? I mean, for
instance, TX
a insert rows and TX b insert other rows and both clients (with
different transactions) starts a seq-scan?
If you are in read-committed mode and both backends start their scans
after the other has made its insert, then yes. Note Markus's point
that both queries must be initiated by concurrent connections. Since
Postgres doesn't have any kind of shared transaction mechanism across
connections then this is inherent.
Erik Jones
Software Developer | Emma®
erik@xxxxxxxxxx
800.595.4401 or 615.292.5888
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