Re: Wait event names mismatch: oldserxid

2018-02-28 Thread Michael Paquier 
On Tue, Feb 27, 2018 at 02:44:37PM -0500, Robert Haas wrote:
> On Fri, Feb 9, 2018 at 8:53 AM, Michael Paquier  wrote:
>> So the docs look correct to me on this side.  What I find weird is the
>> phrasing to define oldserxid.  Instead of that, the current description:
>> Waiting to I/O on an oldserxid buffer.
>> I would suggest "waiting *for* I/O"
>>
>> A small patch is attached.
> 
> Agreed.  Committed.

Thanks, Robert.
--
Michael


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Re: Wait event names mismatch: oldserxid

2018-02-27 Thread Robert Haas 
On Fri, Feb 9, 2018 at 8:53 AM, Michael Paquier  wrote:
> So the docs look correct to me on this side.  What I find weird is the
> phrasing to define oldserxid.  Instead of that, the current description:
> Waiting to I/O on an oldserxid buffer.
> I would suggest "waiting *for* I/O"
>
> A small patch is attached.

Agreed.  Committed.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Re: Wait event names mismatch: oldserxid

2018-02-09 Thread Michael Paquier 
On Fri, Feb 09, 2018 at 07:33:57PM +0530, Ashutosh Bapat wrote:
> I didn't pay attention to the second one. Thanks for pointing that
> out. But then like me a user may first land on OldSerXidLock since
> that is first in the list and get confused. May be we should use names
> which are not prefix of others.

Yeah, I don't think that it would be good to have users abuse of things
like ~ 'oldserxid' to track different event types.  This encourages such
filters on pg_stat_activity.
--
Michael


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Re: Wait event names mismatch: oldserxid

2018-02-09 Thread Ashutosh Bapat 
On Fri, Feb 9, 2018 at 7:23 PM, Michael Paquier  wrote:
> On Fri, Feb 09, 2018 at 06:04:39PM +0530, Ashutosh Bapat wrote:
>> Name for wait event "LWTRANCHE_OLDSERXID_BUFFERS" is printed as
>> "oldserxid", but documentation at
>> https://www.postgresql.org/docs/10/static/monitoring-stats.html does
>> not have exact same event there. Instead it has
>>
>> OldSerXidLock Waiting to read or record conflicting serializable
>> transactions.
>
> I see two events defined here in the code of type LWLock dedicated to
> oldserxid:
> - OldSerXidLock which is a wait event defined as it is part of
> LWLockNames.
> - oldserxid, which gets defined in SimpleLruInit(), which itself calls
> LWLockRegisterTranche() to define a second event of type LWLock.

I didn't pay attention to the second one. Thanks for pointing that
out. But then like me a user may first land on OldSerXidLock since
that is first in the list and get confused. May be we should use names
which are not prefix of others.

>
> So the docs look correct to me on this side.  What I find weird is the
> phrasing to define oldserxid.  Instead of that, the current description:
> Waiting to I/O on an oldserxid buffer.
> I would suggest "waiting *for* I/O"
>

+1.

-- 
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database Company

Re: Wait event names mismatch: oldserxid

2018-02-09 Thread Michael Paquier 
On Fri, Feb 09, 2018 at 06:04:39PM +0530, Ashutosh Bapat wrote:
> Name for wait event "LWTRANCHE_OLDSERXID_BUFFERS" is printed as
> "oldserxid", but documentation at
> https://www.postgresql.org/docs/10/static/monitoring-stats.html does
> not have exact same event there. Instead it has
> 
> OldSerXidLock Waiting to read or record conflicting serializable
> transactions.

I see two events defined here in the code of type LWLock dedicated to
oldserxid:
- OldSerXidLock which is a wait event defined as it is part of
LWLockNames.
- oldserxid, which gets defined in SimpleLruInit(), which itself calls
LWLockRegisterTranche() to define a second event of type LWLock.

So the docs look correct to me on this side.  What I find weird is the
phrasing to define oldserxid.  Instead of that, the current description:
Waiting to I/O on an oldserxid buffer.
I would suggest "waiting *for* I/O"

A small patch is attached.

Thanks,
--
Michael
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index e138d1ef07..82c015806e 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -1068,7 +1068,7 @@ postgres   27093  0.0  0.0  30096  2752 ?Ss   11:34   0:00 postgres: ser
 
 
  oldserxid
- Waiting to I/O on an oldserxid buffer.
+ Waiting for I/O on an oldserxid buffer.
 
 
  wal_insert


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