Horton

RE: Libpq support to connect to standby server as priority

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

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From: "Tsunakawa, Takayuki" <tsunakawa.takay@jp.fujitsu.com>
To: 'Alvaro Herrera from 2ndQuadrant' <alvherre@alvh.no-ip.org>
Cc: Haribabu Kommi <kommi.haribabu@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Laurenz Albe <laurenz.albe@cybertec.at>, Tom Lane <tgl@sss.pgh.pa.us>, Dave Cramer <pg@fastcrypt.com>, Jing Wang <jingwangian@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-09-11T00:10:59Z
Lists: pgsql-hackers 
From: Alvaro Herrera from 2ndQuadrant [mailto:alvherre@alvh.no-ip.org]
> Testing protocol version 2 is difficult!  Almost every single test fails
> because of error messages being reported differently; and streaming
> replication (incl. pg_basebackup) doesn't work at all because it's not
> possible to establish replication connections.  Manual inspection shows
> it behaves correctly.

Yeah, the code path for protocol v2 is sometimes annoying.  I wish v2 support will be dropped soon.  I know there was a discussion on it, but I didn't track the conclusion.


> Remaining patchset attached (per my count it's v13 of your patchset.

I'm afraid those weren't attached.


> think we should merge one half of it with each of the other two patches
> where the changes are introduced (0003 and 0004).  I'm not convinced
> that we need 0004-0006 to be separate commits.

It was hard to review those separate patches, so I think it's better to merge those.  OTOH, I can understand Haribabu-san's idea that the community may not accept the latter patches, e.g. accept only 0001-0005.


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.