Re: [bug fix] pg_ctl always uses the same event source

On Thu, Dec 5, 2013 at 7:54 PM, MauMau <maumau307@gmail.com> wrote:
> Hello,
>
> I've removed a limitation regarding event log on Windows with the attached
> patch.  I hesitate to admit this is a bug fix and want to regard this an
> improvement, but maybe it's a bug fix from users' perspective.  Actually, I
> received problem reports from some users.
>
>
> [Problem]
> pg_ctl always uses event source "PostgreSQL" to output messages to the event
> log.  Some example messages are:
>
> server starting
> server started
>
> This causes the problems below:
>
> 1. Cannot distinguish PostgreSQL instances because they use the same event
> source.
>
> 2. If you use multiple installations of PostgreSQL on the same machine,
> whether they are the same or different versions, Windows event viewer
> reports an error "event source not found" in the following sequence.  Other
> system administration software which deal with event log may show other
> anomalies.
> 2-1 Install the first PostgreSQL (e.g. 9.3) into <dir_1>, register
> <dir_1>\lib\pgevent.dll for event source "PostgreSQL", then creates
> <instance_1>.
> 2-2 Install the second PostgreSQL (e.g. 9.2) into <dir_2> as part of some
> packaged application, register <dir_2>\lib\pgevent.dll for event source
> "PostgreSQL",

Today, I was trying to reproduce this issue and found that if user tries
to register event source second time with same name, we just replace
the previous event source's path in registry.
Shouldn't we try to stop user at this step only, means if he tries to
register with same event source name more than once return error,
saying event source with same name already exists?


Another thing is after register of pgevent.dll, if I just try to start
PostgreSQL
it shows below messages in EventLog. Although the message has information
about server startup, but the start of Description is something similar to
what you were reporting "event source not found".
Am I missing something?

Steps
1. installation of PostgreSQL from source code using Install.bat in
mdvc directory
2. initdb -D <data_dir>
3. regsvr32 /n /i:PostgreSQL <install_dir_path>\lib\pgevent32.dll
4. Modify postgresql.conf to set log_destination= 'eventlog'
5. pg_ctl.exe start -D ..\..\Data

Log Name:      Application
Source:        PostgreSQL
Date:          1/19/2014 7:49:54 PM
Event ID:      0
Task Category: None
Level:         Information
Keywords:      Classic
User:          N/A
Computer:      WIN-NGNN8PKIMD7
Description:
The description for Event ID 0 from source PostgreSQL cannot be found.
Either the component that raises this event is not installed on your
local computer or the installation is corrupted. You can install or
repair the component on the local computer.

If the event originated on another computer, the display information
had to be saved with the event.

The following information was included with the event:

LOG:  ending log output to stderr
HINT:  Future log output will go to log destination "eventlog".


the message resource is present but the message is not found in the
string/message table


With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com