Horton

Re: Libpq support to connect to standby server as priority

Haribabu Kommi <kommi.haribabu@gmail.com>

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From: Haribabu Kommi <kommi.haribabu@gmail.com>
To: jingwangian@gmail.com
Cc: Pg Hackers <pgsql-hackers@postgresql.org>, "Tsunakawa, Takayuki" <tsunakawa.takay@jp.fujitsu.com>
Date: 2018-06-19T03:19:29Z
Lists: pgsql-hackers

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On Wed, Jan 24, 2018 at 9:01 AM Jing Wang <jingwangian@gmail.com> wrote:

> Hi All,
>
> Recently I put a proposal to support 'prefer-read' parameter in
> target_session_attrs in libpq. Now I updated the patch with adding content
> in the sgml and regression test case.
>
> Some people may have noticed there is already another patch (
> https://commitfest.postgresql.org/15/1148/ ) which looks similar with
> this. But I would say this patch is more complex than my proposal.
>
> It is better separate these 2 patches to consider.
>

I also feel prefer-read and read-only options needs to take as two
different options.
prefer-read is simple to support than read-only.

Here I attached an updated patch that is rebased to the latest master and
also
fixed some of the corner scenarios.

Regards,
Haribabu Kommi
Fujitsu Australia

Commits

  1. Make test_target_session_attrs more robust against connection failure.

  2. Extend the abilities of libpq's target_session_attrs parameter.

  3. Mark default_transaction_read_only as GUC_REPORT.

  4. Introduce a new GUC_REPORT setting "in_hot_standby".

  5. Avoid spamming the client with multiple ParameterStatus messages.

  6. Avoid harmless Valgrind no-buffer-pin errors.

  7. Restructure libpq code to remove some duplicity

  8. libpq: Add target_session_attrs parameter.