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nabbisen
nabbisen

Posted on • Updated on • Originally published at obsd.solutions

PostgreSQL on OpenBSD: Upgrade 14 to 15 with pg_upgrade

#postgres #database #openbsd #migration

Summary

OpenBSD gives us good documentation as a series of the project. (For example, the man pages are cared and kept maintained.) It's applied to principal service packages as well as the OS. So is as to PostgreSQL.

Well, according to their pkg-readme on PostgreSQL (/usr/local/share/doc/pkg-readmes/postgresql-server), they suggest we have two ways to upgrade the database:

  1. pg_dumpall
  2. pg_upgrade

The former is slower so is not suitable for big databases, but doesn't require the additional package. The latter is vice versa.

I wrote about the former, in which I upgraded PostgreSQL 12 to 13. It is the turn of the latter.

Environment

  • OS: OpenBSD 7.3 (<- 7.2)
  • DB: PostgreSQL 15 (<- 14)

Tutorial

Here is a step-by-step guide. Let's begin.

Backup (Optional)

When you worry about backup, pg_dumpall is available:

$ pg_dumpall > pg.sqldump
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Here you will be asked by Password: at the number of databases.

Install pg_upgrade

Get it via the ports package system:

$ doas pkg_add postgresql-pg_upgrade
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The result was:

quirks-6.42 signed on 2023-04-06T19:16:59Z
postgresql-pg_upgrade-14.5:postgresql-previous-13.5p0: ok
postgresql-pg_upgrade-14.5: ok
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Upgrade OBSD 7.2 to 7.3 and the PG package

It is about upgrading OpenBSD instead of PostgreSQL.

Run sysupgrade, sysmerge and pkg_add -u in this order.
The detail is in this post.

Well, within the process above, you will be asked about PostgreSQL like below:

postgresql-server-15.2p0: Updating across a major version - data migration needed, see the pkg-readme.
Do you want to update now ? [y/N/a] y
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Enter "y", and the package (not the database itself) of PostgreSQL will be upgraded. It will be printed out like below:

postgresql-client+postgresql-contrib+postgresql-pg_upgrade+postgresql-server-14.5->postgresql-client-15.2+postgresql-contrib-15.2+postgresql-pg_upgrade-15.2+postgresql-server-15.2p0: ok
(...)
New and changed readme(s):
    /usr/local/share/doc/pkg-readmes/postgresql-server
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Stop the daemon

Get ready by stopping the server:

$ doas rcctl stop postgresql
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The result was:

postgresql(ok)
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Now we are ready. Let's upgrade the database !!

Create PostgreSQL 15 cluster

Prepare for creating the data directory.
Move the current:

$ doas mv /var/postgresql/data /var/postgresql/data-14
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Then mkdir it and initdb for PostgreSQL:

$ # doas su _postgresql -c "mkdir /var/postgresql/data && cd /var/postgresql && \
        initdb -D /var/postgresql/data -U postgres -A scram-sha-256 -E UTF8 -W"
$ doas su _postgresql -c "mkdir /var/postgresql/data && cd /var/postgresql && \
      initdb -D /var/postgresql/data -U postgres -A scram-sha-256 -E UTF8 --locale=ja_JP.UTF-8 -W"
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The former above is due to the pkg-readme, and the latter is specific for my case, in which --locale=(...) option is added.

The result was:

The files belonging to this database system will be owned by user "_postgresql".
This user must also own the server process.

The database cluster will be initialized with locale "ja_JP.UTF-8".
initdb: could not find suitable text search configuration for locale "ja_JP.UTF-8"
The default text search configuration will be set to "simple".

Data page checksums are disabled.

Enter new superuser password: 
Enter it again:
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Enter the password of your PostgreSQL superuser twice. Then it will be followed by the below:

fixing permissions on existing directory /var/postgresql/data ... ok
creating subdirectories ... ok
selecting dynamic shared memory implementation ... posix
selecting default max_connections ... 20
selecting default shared_buffers ... 128MB
selecting default time zone ... Asia/Tokyo
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... ok
syncing data to disk ... ok

Success. You can now start the database server using:

    pg_ctl -D /var/postgresql/data -l logfile start
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Yay. The database is initiated with them generated.

Configure for migration

The steps here are temporary for the data migration.

Edit pg_hba.conf of the current (and also the next):

$ doas nvim /var/postgresql/data-14/pg_hba.conf
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in order to allow local connection by the superuser:

  # TYPE  DATABASE        USER            ADDRESS                 METHOD
+ local all postgres trust
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Note that you should put the line at the top in order to let it be the most highly prioritized.

Then copy the files below including pg_hba.conf to the data directory of 15, the latest:

$ doas cp -p /var/postgresql/data-14/pg_hba.conf /var/postgresql/data/

$ # in addition, in case that tls is used:
$ doas cp -p /var/postgresql/data-14/server.{crt,key} /var/postgresql/data/
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Run pg_upgrade

OK. Your database is now waiting for the upgrade !!! Run the command lines (thanks to the software and the pkg-readme):

$ doas su _postgresql -c "cd /var/postgresql && \
      pg_upgrade -b /usr/local/bin/postgresql-14/ -B /usr/local/bin \
      -U postgres -d /var/postgresql/data-14/ -D /var/postgresql/data"
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The result was below in my case:

Performing Consistency Checks
-----------------------------
Checking cluster versions                                   ok
Checking database user is the install user                  ok
Checking database connection settings                       ok
Checking for prepared transactions                          ok
Checking for system-defined composite types in user tables  ok
Checking for reg* data types in user tables                 ok
Checking for contrib/isn with bigint-passing mismatch       ok
Creating dump of global objects                             ok
Creating dump of database schemas
                                                            ok
Checking for presence of required libraries                 ok
Checking database user is the install user                  ok
Checking for prepared transactions                          ok
Checking for new cluster tablespace directories             ok

If pg_upgrade fails after this point, you must re-initdb the
new cluster before continuing.

Performing Upgrade
------------------
Analyzing all rows in the new cluster                       ok
Freezing all rows in the new cluster                        ok
Deleting files from new pg_xact                             ok
Copying old pg_xact to new server                           ok
Setting oldest XID for new cluster                          ok
Setting next transaction ID and epoch for new cluster       ok
Deleting files from new pg_multixact/offsets                ok
Copying old pg_multixact/offsets to new server              ok
Deleting files from new pg_multixact/members                ok
Copying old pg_multixact/members to new server              ok
Setting next multixact ID and offset for new cluster        ok
Resetting WAL archives                                      ok
Setting frozenxid and minmxid counters in new cluster       ok
Restoring global objects in the new cluster                 ok
Restoring database schemas in the new cluster
                                                            ok
Copying user relation files
                                                            ok
Setting next OID for new cluster                            ok
Sync data directory to disk                                 ok
Creating script to delete old cluster                       ok
Checking for extension updates                              ok

Upgrade Complete
----------------
Optimizer statistics are not transferred by pg_upgrade.
Once you start the new server, consider running:
    /usr/local/bin/vacuumdb -U postgres --all --analyze-in-stages

Running this script will delete the old cluster's data files:
    ./delete_old_cluster.sh
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Successful :)

Restore configuration

Restore the configuration by removing the temporary line:

$ doas nvim /var/postgresql/data/pg_hba.conf

$ # in addition, if you care about restoring the previous one:
$ doas nvim /var/postgresql/data-14/pg_hba.conf
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like below:

  # TYPE  DATABASE        USER            ADDRESS                 METHOD
- local all postgres trust
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Configure for PostgreSQL 15 (Optional)

When you have specific configuration with postgresql.conf etc., apply them:

$ # create the backup (optional):
$ doas cp -p /var/postgresql/data/postgresql.conf /var/postgresql/data/postgresql.conf.org

$ doas nvim /var/postgresql/data/postgresql.conf
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like below (for example):

  (...)
+ listen_addresses = '*'
  (...)
+ ssl = on
  (...)
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Besides, as to postgresql.conf, the original one is in /usr/local/share/postgresql/postgresql.conf.sample.

All on the upgrade have been done.

Start the daemon again

Let's start the database server:

$ doas rcctl start postgresql
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I hope the result is successful :)

Remove the package (Optional)

You are now free to farewell with appreciation to the package which worked fine:

$ doas pkg_delete postgresql-pg_upgrade
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The result was:

postgresql-pg_upgrade-15.2: ok
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Conclusion

Through the steps above, we can upgrade PostgreSQL 14 to 15 with upgrading OpenBSD 7.2 to 7.3.

Besides, the data-14 directory may become "old" one in some future.

Wish you pretty happy time with the latest PostgreSQL on the latest OpenBSD 🌟

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