[HACKERS] Is LISTEN/NOTIFY reliable?
Hi, Does anybody know PostgreSQL LISTEN/NOTIFY is more reliable than previous versions? I vaguely recall that in the previous implementation, message sent by NOTIFY may not be reached to listner. Does PostgreSQL 9.0's new implementation guarantee that the message is received by the listener? -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese: http://www.sraoss.co.jp -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Is LISTEN/NOTIFY reliable?
On Sat, Oct 16, 2010 at 3:27 AM, Tatsuo Ishii is...@postgresql.org wrote: Does anybody know PostgreSQL LISTEN/NOTIFY is more reliable than previous versions? I vaguely recall that in the previous implementation, message sent by NOTIFY may not be reached to listner. Does PostgreSQL 9.0's new implementation guarantee that the message is received by the listener? I think it was always intended to be reliable (otherwise it's not much good). I think I remember a bug where notifications were being lost on Windows under heavy load, but I thought we fixed that... -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Is LISTEN/NOTIFY reliable?
Tatsuo Ishii is...@postgresql.org writes: Does anybody know PostgreSQL LISTEN/NOTIFY is more reliable than previous versions? I vaguely recall that in the previous implementation, message sent by NOTIFY may not be reached to listner. Does PostgreSQL 9.0's new implementation guarantee that the message is received by the listener? No more or less than the old one did. The old design intentionally dropped duplicate notifications, and the new one does too (though with a narrower definition of duplicate). Modulo that well-documented behavior, I know of no reason to describe either the old or new code as unreliable. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Is LISTEN/NOTIFY reliable?
On 10/16/2010 09:04 AM, Robert Haas wrote: On Sat, Oct 16, 2010 at 3:27 AM, Tatsuo Ishiiis...@postgresql.org wrote: Does anybody know PostgreSQL LISTEN/NOTIFY is more reliable than previous versions? I vaguely recall that in the previous implementation, message sent by NOTIFY may not be reached to listner. Does PostgreSQL 9.0's new implementation guarantee that the message is received by the listener? I think it was always intended to be reliable (otherwise it's not much good). I think I remember a bug where notifications were being lost on Windows under heavy load, but I thought we fixed that... Here's what the docs say: If the same channel name is signaled multiple times from the same transaction with identical payload strings, the database server can decide to deliver a single notification only. On the other hand, notifications with distinct payload strings will always be delivered as distinct notifications. Similarly, notifications from different transactions will never get folded into one notification. Except for dropping later instances of duplicate notifications, NOTIFY guarantees that notifications from the same transaction get delivered in the order they were sent. cheers andrew
Re: [HACKERS] Is LISTEN/NOTIFY reliable?
On Sat, Oct 16, 2010 at 3:27 AM, Tatsuo Ishii is...@postgresql.org wrote: Does anybody know PostgreSQL LISTEN/NOTIFY is more reliable than previous versions? ,A (BI vaguely recall that in the previous implementation, message sent by NOTIFY may not be reached to listner. Does PostgreSQL 9.0's new implementation guarantee that the message is received by the listener? I think it was always intended to be reliable (otherwise it's not much good). I think I remember a bug where notifications were being lost on Windows under heavy load, but I thought we fixed that... Thanks. Maybe I was confused by the bug. -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese: http://www.sraoss.co.jp -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
