Re: [PATCH] Add PQconninfoParseParams and PQconninfodefaultsMerge to libpq

On 18.02.2013 06:07, Amit Kapila wrote:
> On Sunday, February 17, 2013 8:44 PM Phil Sorber wrote:
>> On Sun, Feb 17, 2013 at 1:35 AM, Amit kapila<amit.kapila@huawei.com>
>> wrote:
>>> Now the patch of Phil Sober provides 2 new API's
>> PQconninfoParseParams(), and PQconninfodefaultsMerge(),
>>> using these API's I can think of below way for patch "pass a
>> connection string to pg_basebackup, ..."
>>>
>>> 1. Call existing function PQconinfoParse() with connection string
>> input by user and get PQconninfoOption.
>>>
>>> 2. Now use the existing keywords (individual options specified by
>> user) and extract the keywords from
>>>     PQconninfoOption structure and call new API
>> PQconninfoParseParams() which will return PQconninfoOption.
>>>     The PQconninfoOption structure returned in this step will contain
>> all keywords
>>>
>>> 3. Call PQconninfodefaultsMerge() to merge any default values if
>> exist. Not sure if this step is required?
>>>
>>> 4. Extract individual keywords from PQconninfoOption structure and
>> call PQconnectdbParams.
>>>
>>> Is this inline with what you have in mind or you have thought of some
>> other simpler way of using new API's?

Yep, that's roughly what I had in mind. I don't think it's necessary to 
merge defaults in step 3, but it needs to add the "replication=true" and 
"dbname=replication" options.

>> I think what would be nice is an additional connect function that took
>> PQconninfoOption as a parameter. Or at least something that can
>> convert from PQconninfoOption to a connection string or keyword/value
>> arrays.
>
> Yes, it would be better if we would like to use new API's, I think it can
> save step-4 and some part in step-2.

pg_basebackup needs to add options to the array, so I don't think a new 
connect function would help much. It's not a lot of code to iterate 
through the PGconnInfoOption array and turn it back into keywords and 
values arrays, so I'd just do that straight in the client code.

- Heikki