Re: PostgreSQL mirroring from RPM install to Source install

Richard Brosnahan <broz(at)mac(dot)com> writes:
> I've got a PostgreSQL database server version 9.4.1 installed on an OEL 6 server. I have a second PostgreSQL database server version 9.4.1 running on an identical OEL 6 server. The first PostgreSQL was installed by system admins using RPM. The second PostgreSQL was installed from source, using --prefix to set the user and path to the installation. I want to run a mirror on the second server.

> I do not have root, and cannot get root on these systems. Also, the sys admins now refuse to install PostgreSQL anywhere. This is really annoying!

> I've followed all the instructions found here:
> https://www.postgresql.org/docs/9.4/static/warm-standby.html#STREAMING-REPLICATION

> The slave, running PostgreSQL 9.4.1 built from source, runs fine after I've run initdb and set things up.
> When I replace its data directory as part of the mirroring instructions, using pg_basebackup, PostgreSQL won't start.

> I get a checksum error, from pg_ctl.
> 2016-12-15 08:27:14.520 PST >FATAL: incorrect checksum in control file

> My guess is that despite the versions being the same, the binaries are different.

You could try using pg_controldata to compare the pg_control contents;
it should be willing to print field values even if it thinks the checksum
is bad. It would be interesting to see (a) what the master's
pg_controldata prints about its pg_control, (b) what the slave's
pg_controldata prints about pg_control from a fresh initdb there, and
(c) what the slave's pg_controldata prints about the copied pg_control.

I am a little suspicious about whether the PG versions are really the same.
There's a bug in the 9.5.x series that it will issue a checksum complaint
not a version-number complaint if started against a 9.4.x pg_control.

regards, tom lane