On Thursday 21 July 2005 17:18, Michael Fuhr wrote: > If you set AutoCommit to 0 then all statements are inside a > transaction. As you've discovered, SELECT acquires certain locks > that persist for the duration of the transaction, so you must commit > or roll back the transaction to release those locks (read up on > transaction theory to learn more about the rationale for this).
What URL should I read at first? I began with 'http://www.postgresql.org/docs/8.0/interactive/transaction-iso.html'. Is this the right page for starters? BTW: I quote from the page: > When a transaction is on the serializable level, a SELECT query sees > only data committed before the transaction began; it never sees either > uncommitted data or changes committed during transaction execution by > concurrent transactions. (However, the SELECT does see the effects of > previous updates executed within its own transaction, even though they > are not yet committed.) So I opened up two shells and started 'psql' on both shells (marked the command with 1 and 2): 1:begin 2:begin; 1:SELECT * FROM test; id | name ----+------ (0 rows) 2: INSERT INTO test (name) VALUES ('foo'); 1: SELECT * FROM test; id | name ----+------ (0 rows) 2: commit; 1: SELECT * FROM test; id | name ----+------ 1 | foo (1 row) Why do I see in the first transaction data from the commited second transaction? Doesn't prove that the documentation on the above URL wrong? -- So long... Fuzz ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
