Re: Libpq support to connect to standby server as priority

From: Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Anastasia Lubennikova <a(dot)lubennikova(at)postgrespro(dot)ru>, Greg Nancarrow <gregn4422(at)gmail(dot)com>, Peter Smith <smithpb2250(at)gmail(dot)com>, "Smith, Peter" <peters(at)fast(dot)au(dot)fujitsu(dot)com>, David Steele <david(at)pgmasters(dot)net>, "Tsunakawa, Takayuki" <tsunakawa(dot)takay(at)fujitsu(dot)com>, Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>, Dave Cramer <pg(at)fastcrypt(dot)com>, Jing Wang <jingwangian(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Elvis Pranskevichus <elprans(at)gmail(dot)com>
Subject: Re: Libpq support to connect to standby server as priority
Date: 2020-11-24 22:59:17
Message-ID: 20201124225917.GA21884@alvherre.pgsql
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-hackers

On 2020-Nov-24, Tom Lane wrote:

> I'm inclined to go ahead and commit the 0001 patch I posted at [1]
> (ie, change the implementation of GUC_REPORT to avoid intra-query
> reports), since that addresses a performance problem that's
> independent of the goal here. The rest of this seems to still
> be in Greg's court.

Sounded a good idea to me.

> Has anyone got an opinion about the further improvement I suggested:
> >> As it stands, 0001 reduces the ParameterStatus message traffic to
> >> at most one per GUC per query, but it doesn't attempt to eliminate
> >> duplicate ParameterStatus messages altogether. We could do that
> >> as a pretty simple adjustment if we're willing to expend the storage
> >> to remember the last value sent to the client. It might be worth
> >> doing, since for example the function-SET-clause case would typically
> >> lead to no net change in the GUC's value by the end of the query.
> On reflection this seems worth doing, since excess client traffic
> is far from free.

Agreed. If this is just a few hundred bytes of server-side local memory
per backend, it seems definitely worth it.

In response to


Browse pgsql-hackers by date

  From Date Subject
Next Message Tom Lane 2020-11-24 23:19:47 Re: Libpq support to connect to standby server as priority
Previous Message Bossart, Nathan 2020-11-24 22:23:34 A few new options for CHECKPOINT