From: | Itagaki Takahiro <itagaki(dot)takahiro(at)gmail(dot)com> |
---|---|
To: | Magnus Hagander <magnus(at)hagander(dot)net> |
Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: system views for walsender activity |
Date: | 2011-01-04 06:51:09 |
Message-ID: | AANLkTimHipnSBnOd+DybH2nxeVfiK9J7WmuvF5bVELpe@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On Tue, Dec 28, 2010 at 22:17, Magnus Hagander <magnus(at)hagander(dot)net> wrote:
>>> We definitely need the very basic level for 9.1, and we can always
>>> improve on it later :-)
>
>>> pg_stat_walsender. It would then only need the columns for procpid,
>>> usesysid, usename, client_addr, client_port, and the WALsender
>>> specific fields.
> Yeah, agreed. backend_start is probably the best one
Here are patches for pg_stat_walsender.
I split the feature into two pieces:
* get_host_and_port.patch
It separates host and port formatter as a subroutine from pg_stat_activity.
In addition, make pg_stat_get_backend_client_addr/port() functions to
use the subroutine to reduce duplicated codes.
* pg_stat_walsender.patch
It adds pg_stat_walsender system view. It has subset columns of
pg_stat_activity and only one additional WAL sender specific information
via WALSndStatus(). I named the column "sending location" because
standby servers might not have received the WAL record; if we had
synchronous replication, a new "sent location" wold be added.
But the naming is still an open question. Comments welcome.
There is O(max_wal_senders^2) complexity in the view, But I think
it is not so serious problem because we can expect max_wal_senders
is 10 or so at most.
CREATE VIEW pg_stat_walsender AS
SELECT
S.procpid,
S.usesysid,
U.rolname AS usename,
S.client_addr,
S.client_port,
S.backend_start,
S.xlog_sending
FROM pg_stat_get_walsender(NULL) AS S, pg_authid U
WHERE S.usesysid = U.oid;
--
Itagaki Takahiro
Attachment | Content-Type | Size |
---|---|---|
get_host_and_port-20110104.patch | application/octet-stream | 8.6 KB |
pg_stat_walsender-20110104.patch | application/octet-stream | 13.9 KB |
From | Date | Subject | |
---|---|---|---|
Next Message | Jeff Davis | 2011-01-04 07:29:45 | WIP: Range Types |
Previous Message | Robert Haas | 2011-01-04 04:13:04 | Re: Re: [COMMITTERS] pgsql: Reduce spurious Hot Standby conflicts from never-visible records |