Re: Patch: Implement failover on libpq connect level.

On Tue, Nov 29, 2016 at 3:14 PM, Robert Haas  wrote:
> On Tue, Nov 29, 2016 at 2:19 PM, Kuntal Ghosh
>  wrote:
>> On Thu, Nov 24, 2016 at 5:46 PM, Mithun Cy  wrote:
>>> I have taken this suggestion now renamed target_server_type to
>>> target_session_attrs with possible 2 values "read-write", "any".
>>> May be we could expand to "readonly" and "prefer-readonly" in next patch
>>> proposal. Attaching the patch for same.
>> I was doing some testing with the patch and I found some inconsistency
>> in the error message.
>> I've a read-only server running on port 5433 and no server on 5436 and 5438.
>>
>> command: bin/psql
>> 'postgresql://localhost:5436,localhost:5433,localhost:5438/postgres?target_session_attrs=read-write'
>>
>> I get the following error message.
>>
>> psql: could not make a writable connection to server "localhost:5433"
>> could not connect to server: Connection refused
>>     Is the server running on host "localhost" (::1) and accepting
>>     TCP/IP connections on port 5438?
>> could not connect to server: Connection refused
>>     Is the server running on host "localhost" (127.0.0.1) and accepting
>>     TCP/IP connections on port 5438?
>>
>> It didn't show any error message for port 5436. But, if I modify the
>> connection string as following:
>>
>> command: bin/psql
>> 'postgresql://localhost:5433,localhost:5436,localhost:5438/postgres?target_session_attrs=read-write'
>>
>> I get the following error message:
>>
>> psql: could not make a writable connection to server "localhost:5433"
>> could not connect to server: Connection refused
>>     Is the server running on host "localhost" (::1) and accepting
>>     TCP/IP connections on port 5436?
>> could not connect to server: Connection refused
>>     Is the server running on host "localhost" (127.0.0.1) and accepting
>>     TCP/IP connections on port 5436?
>> could not connect to server: Connection refused
>>     Is the server running on host "localhost" (::1) and accepting
>>     TCP/IP connections on port 5438?
>> could not connect to server: Connection refused
>>     Is the server running on host "localhost" (127.0.0.1) and accepting
>>     TCP/IP connections on port 5438?
>
> Hmm, maybe the query buffer is getting cleared someplace in there.  We
> might need to save/restore it.

Not the query buffer.  conn->errorMessage.

-- 
Robert Haas
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