Albe Laurenz ha scritto:
Nico Sabbi wrote:
/From:
http://www.postgresql.org/docs/8.2/interactive/transaction-iso.html
"
Read Committed/ [...]
to me the above sentence sounds inconsistent: it's
asserting that both 1) and 2) apply:
1) it never sees ... changes committed during query
execution by concurrent transactions
2) Notice that two successive SELECT commands can see
different data, even though they are within a single
transaction, if other transactions commit changes
during execution of the first SELECT
Can anyone explain, please?
1) means: as long as the first SELECT runs ("during
query execution"), you won't see changes made by
another transaction.
2) means: when you run a second SELECT, that SELECT
will see changes made by other transactions, even if
both SELECTs are in one (read commited) transaction.
That doesn't sound contradictory to me.
There is a difference between "during query execution"
and "within a single transaction", maybe that is where
your problem comes from.
Yours,
Laurenz Albe
well, I know how read committed behaves, but
I don't see why should anyone expect an update of the resultset
of the currently executing query after a commit by a different
transaction.
Thanks everybody who replied,
Nico
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