[pgpool-general: 8726] Re: PgPool-II v4.4 extension package for PostgreSQL 14 requires PostgreSQL 15 ???

[zam bak]

On Thu, Apr 6, 2023 at 8:23 PM Bo Peng <pengbo at sraoss.co.jp> wrote:
>
> Hello,
>
> > On Thu, Apr 6, 2023 at 3:53 AM Bo Peng <pengbo at sraoss.co.jp> wrote:
> > >
> > > Hello,
> > >
> > > > On Wed, Apr 5, 2023 at 2:46 PM zam bak <zam6ak at gmail.com> wrote:
> > > > >
> > > > > On Tue, Apr 4, 2023 at 9:33 PM Bo Peng <pengbo at sraoss.co.jp> wrote:
> > > > > >
> > > > > > Hello,
> > > > > >
> > > > > > > Hello
> > > > > > >
> > > > > > > We are trying to install PgPool-II extensions for PostgreSQL as per docs
> > > > > > > https://www.pgpool.net/docs/44/en/html/install-rpm.html#INSTALLING-RPM
> > > > > > >
> > > > > > > We have separate servers for pgpool and postgresql (primary + 1 replica)
> > > > > > > Our environment is
> > > > > > > * Rocky Linux v8
> > > > > > > * PostgreSQL v14.7
> > > > > > > * PgPool v4.4
> > > > > > >
> > > > > > > On postgres servers, after installing PostgreSQL 14 using PGDG
> > > > > > > repositories and trying to install pgpool extensions package I get
> > > > > > > following error:
> > > > > > >
> > > > > > > dnf install pgpool-II-pg14-extensions
> > > > > > >
> > > > > > > Last metadata expiration check: 0:01:02 ago on Mon 03 Apr 2023 11:46:53 AM EDT.
> > > > > > > Error:
> > > > > > >  Problem: package pgpool-II-pg14-extensions-4.4.2-1.rhel8.x86_64
> > > > > > > requires pgpool-II-pcp, but none of the providers can be installed
> > > > > > >   - cannot install the best candidate for the job
> > > > > > >   - nothing provides postgresql15-server needed by
> > > > > > > pgpool-II-pcp-4.4.1-1.rhel8.x86_64
> > > > > > >   - nothing provides postgresql15-server needed by
> > > > > > > pgpool-II-pcp-4.4.2-1.rhel8.x86_64
> > > > > > > (try to add '--skip-broken' to skip uninstallable packages or
> > > > > > > '--nobest' to use not only best candidate packages)
> > > > > >
> > > > > > If you want to install Pgpool-II from Pgpool-II repository,
> > > > > > you need to disable PGDG repository.
> > > > > >
> > > > > > Try the following command:
> > > > > >
> > > > > >   dnf install --disablerepo=pgdg* pgpool-II-pg14-extensions
> > > > >
> > > > > OK, this was not obvious because PostgreSQL gets installed from one of
> > > > > the PGDG repos (in my case PostgreSQL 14 from "pgdg14" repository)
> > > > > However, the above command wants to install 2 dependencies
> > > > > 1. libmemcached-libs  (from "appstream" repo)
> > > > > 2. pgpool-II-pg11        (from "pgpool44" repo)
> > > > >
> > > > > I understand the need for libmemcached-libs, but why do pgpool
> > > > > extensions for PostgreSQL 14 depend on PgPool for version 11 of
> > > > > Postgres?
> > > > > Is that normal or?
> > > >
> > > > This command seems to "pull in" matching versions:
> > > > dnf install --disablerepo="*" --enablerepo="appstream,pgpool44"
> > > > pgpool-II-pg14 pgpool-II-pg14-extensions
> > > >
> > > > Maybe this is correct?
> > >
> > > If you want to install pgpool-II-pg14, you need to
> > > explicitly specify the major version.
> >
> > I don't want to install pgpool-II on PostgreSQL servers, just the extension.
> > But pgpool-II-pg14-extensions **depends on** pgpool-II package
> > And unless you specify it - it installs pgpool-II-pg11.....
> >
> > So if I am installing extensions on PostgreSQL 14 server..
> > this:
> > dnf install --disablerepo="*" --enablerepo="appstream,pgpool44"
> > will want to install "pgpool-II-pg11 " as dependency
> >
> > If I want to "match" the versions I have to this:
> > dnf install --disablerepo="*" --enablerepo="appstream,pgpool44"
> > pgpool-II-pg14 pgpool-II-pg14-extensions
> >
> > either way, you cannot install *just* pgpool-II-pg14-extensions ....
>
> Because pgpool-II-pg14-extensions requires the library /usr/lib64/libpcp.so.2
> included in pgpool-II-pgX, you have to install pgpool-II-pgX
> in PostgreSQL server.
>
> Althougt /usr/lib64/libpcp.so.2 is same in pgpool-II-pg11 or pgpool-II-pg14,
> it is recommended to explicitly specify the version.
>
Dependency on pgpool-II-pgX package is fine and I agree its probably
better to be specific with versions.


> I am not sure,but I don't think the default dependency is a pgpool issue.
>

I think the biggest "gotcha" (for me at least) was having to disable
PGDG repo while installing extensions and having to specify exact
packages
If you just installed PostgreSQL from PGDG repos and are trying to
install pgpool extensions , this was not obvious step.
Perhaps mentioning that on documentation would save someone else time
in the future
https://www.pgpool.net/docs/44/en/html/install-rpm.html#INSTALLING-RPM

Thank you for all the help provided!

> --
> Bo Peng <pengbo at sraoss.co.jp>
> SRA OSS LLC
> https://www.sraoss.co.jp/