[pgpool-general: 8727] Re: PgPool-II v4.4 extension package for PostgreSQL 14 requires PostgreSQL 15 ???

[Bo Peng]

Hello,

On Thu, 6 Apr 2023 21:56:43 -0400
zam bak <zam6ak at gmail.com> wrote:

> 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!

Yes. You are correct.
Thank you for your advices.
The documentation needs to be improved.
I will do that.

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