RE: Libpq support to connect to standby server as priority

Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com>

From: "Tsunakawa, Takayuki" <tsunakawa.takay@jp.fujitsu.com>
To: 'Haribabu Kommi' <kommi.haribabu@gmail.com>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>, Tom Lane <tgl@sss.pgh.pa.us>, Dave Cramer <pg@fastcrypt.com>, Robert Haas <robertmhaas@gmail.com>, "Jing Wang" <jingwangian@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-02-22T06:45:32Z
Lists: pgsql-hackers
From: Haribabu Kommi [mailto:kommi.haribabu@gmail.com]
Here I attached first set of patches that implemented the prefer-read option
> after reporting the transaction_read_only GUC to client. Along the lines
> of adding prefer-read option patch,

Great, thank you!  I'll review and test it.


> 3. Existing read-write code is modified to use the new reported GUC instead
> of executing the show command.

Is the code path left to use SHOW for older servers?


Regards
Takayuki Tsunakawa

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.