Re: Multiple hosts in connection string failed to failover in non-hot standby mode - Mailing list pgsql-hackers

From Hubert Zhang
Subject Re: Multiple hosts in connection string failed to failover in non-hot standby mode
Date
Msg-id SN6PR05MB4909B53E8D3D8523D72328EAC9AB0@SN6PR05MB4909.namprd05.prod.outlook.com
Whole thread Raw
In response to Re: Multiple hosts in connection string failed to failover in non-hot standby mode  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Multiple hosts in connection string failed to failover in non-hot standby mode  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Hi Tom,

I agree to get detailed error message for each failed host as your patch 0001.

As for patch 0004, find ':' after "could not connect to" may failed when error message like:
"could not connect to host "localhost" (::1), port 12345: Connection refused", where p2 will point to "::1" instead of ": Connection refused". But since it's only used for test case, we don't need to filter the error message precisely.

```
ecpg_filter_stderr(const char *resultfile, const char *tmpfile)
{
    ......
    char       *p1 = strstr(linebuf.data, "could not connect to ");
    if (p1)
    {
        char       *p2 = strchr(p1, ':');
        if (p2)
            memmove(p1 + 17, p2, strlen(p2) + 1);
    }
}
```

Thanks,
Hubert


From: Tom Lane <tgl@sss.pgh.pa.us>
Sent: Monday, January 11, 2021 10:56 AM
To: Hubert Zhang <zhubert@vmware.com>
Cc: tsunakawa.takay@fujitsu.com <tsunakawa.takay@fujitsu.com>; pgsql-hackers@postgresql.org <pgsql-hackers@postgresql.org>
Subject: Re: Multiple hosts in connection string failed to failover in non-hot standby mode
 
I wrote:
> I feel pretty good about 0001: it might be committable as-is.  0002 is
> probably subject to bikeshedding, plus it has a problem in the ECPG tests.
> Two of the error messages are now unstable because they expose
> chosen-at-random socket paths:
> ...
> I don't have any non-hacky ideas what to do about that.  The extra detail
> seems useful to end users, but we don't have any infrastructure that
> would allow filtering it out in the ECPG tests.

So far the only solution that comes to mind is to introduce some
infrastructure to do that filtering.  0001-0003 below are unchanged,
0004 patches up the ecpg test framework with a rather ad-hoc filtering
function.  I'd feel worse about this if there weren't already a very
ad-hoc filtering function there ;-)

This set passes check-world for me; we'll soon see what the cfbot
thinks.

                        regards, tom lane

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