xenial (1) pg_upgrade.1.gz

Provided by: postgresql-9.5_9.5.25-0ubuntu0.16.04.1_amd64 bug

NAME

       pg_upgrade - upgrade a PostgreSQL server instance

SYNOPSIS

       pg_upgrade -b oldbindir -B newbindir -d olddatadir -D newdatadir [option...]

DESCRIPTION

       pg_upgrade (formerly called pg_migrator) allows data stored in PostgreSQL data files to be upgraded to a
       later PostgreSQL major version without the data dump/reload typically required for major version
       upgrades, e.g., from 8.4.7 to the current major release of PostgreSQL. It is not required for minor
       version upgrades, e.g., from 9.0.1 to 9.0.4.

       Major PostgreSQL releases regularly add new features that often change the layout of the system tables,
       but the internal data storage format rarely changes.  pg_upgrade uses this fact to perform rapid upgrades
       by creating new system tables and simply reusing the old user data files. If a future major release ever
       changes the data storage format in a way that makes the old data format unreadable, pg_upgrade will not
       be usable for such upgrades. (The community will attempt to avoid such situations.)

       pg_upgrade does its best to make sure the old and new clusters are binary-compatible, e.g., by checking
       for compatible compile-time settings, including 32/64-bit binaries. It is important that any external
       modules are also binary compatible, though this cannot be checked by pg_upgrade.

       pg_upgrade supports upgrades from 8.4.X and later to the current major release of PostgreSQL, including
       snapshot and alpha releases.

OPTIONS

       pg_upgrade accepts the following command-line arguments:

       -b bindir
       --old-bindir=bindir
           the old PostgreSQL executable directory; environment variable PGBINOLD

       -B bindir
       --new-bindir=bindir
           the new PostgreSQL executable directory; environment variable PGBINNEW

       -c
       --check
           check clusters only, don't change any data

       -d datadir
       --old-datadir=datadir
           the old cluster data directory; environment variable PGDATAOLD

       -D datadir
       --new-datadir=datadir
           the new cluster data directory; environment variable PGDATANEW

       -j njobs
       --jobs=njobs
           number of simultaneous processes or threads to use

       -k
       --link
           use hard links instead of copying files to the new cluster

       -o options
       --old-options options
           options to be passed directly to the old postgres command; multiple option invocations are appended

       -O options
       --new-options options
           options to be passed directly to the new postgres command; multiple option invocations are appended

       -p port
       --old-port=port
           the old cluster port number; environment variable PGPORTOLD

       -P port
       --new-port=port
           the new cluster port number; environment variable PGPORTNEW

       -r
       --retain
           retain SQL and log files even after successful completion

       -U username
       --username=username
           cluster's install user name; environment variable PGUSER

       -v
       --verbose
           enable verbose internal logging

       -V
       --version
           display version information, then exit

       -?
       --help
           show help, then exit

USAGE

       These are the steps to perform an upgrade with pg_upgrade:

        1. Optionally move the old cluster: If you are using a version-specific installation directory, e.g.,
           /opt/PostgreSQL/9.1, you do not need to move the old cluster. The graphical installers all use
           version-specific installation directories.

           If your installation directory is not version-specific, e.g., /usr/local/pgsql, it is necessary to
           move the current PostgreSQL install directory so it does not interfere with the new PostgreSQL
           installation. Once the current PostgreSQL server is shut down, it is safe to rename the PostgreSQL
           installation directory; assuming the old directory is /usr/local/pgsql, you can do:

               mv /usr/local/pgsql /usr/local/pgsql.old

           to rename the directory.

        2. For source installs, build the new version: Build the new PostgreSQL source with configure flags that
           are compatible with the old cluster.  pg_upgrade will check pg_controldata to make sure all settings
           are compatible before starting the upgrade.

        3. Install the new PostgreSQL binaries: Install the new server's binaries and support files.  pg_upgrade
           is included in a default installation.

           For source installs, if you wish to install the new server in a custom location, use the prefix
           variable:

               make prefix=/usr/local/pgsql.new install

        4. Initialize the new PostgreSQL cluster: Initialize the new cluster using initdb. Again, use compatible
           initdb flags that match the old cluster. Many prebuilt installers do this step automatically. There
           is no need to start the new cluster.

        5. Install custom shared object files: Install any custom shared object files (or DLLs) used by the old
           cluster into the new cluster, e.g., pgcrypto.so, whether they are from contrib or some other source.
           Do not install the schema definitions, e.g., CREATE EXTENSION pgcrypto, because these will be
           upgraded from the old cluster. Also, any custom full text search files (dictionary, synonym,
           thesaurus, stop words) must also be copied to the new cluster.

        6. Adjust authentication: pg_upgrade will connect to the old and new servers several times, so you might
           want to set authentication to peer in pg_hba.conf or use a ~/.pgpass file (see Section 31.15, “The
           Password File”, in the documentation).

        7. Stop both servers: Make sure both database servers are stopped using, on Unix, e.g.:

               pg_ctl -D /opt/PostgreSQL/8.4 stop
               pg_ctl -D /opt/PostgreSQL/9.0 stop

           or on Windows, using the proper service names:

               NET STOP postgresql-8.4
               NET STOP postgresql-9.0

           Streaming replication and log-shipping standby servers can remain running until a later step.

        8. Prepare for standby server upgrades: If you are upgrading standby servers using methods outlined in
           section Step 10, verify that the old standby servers are caught up by running pg_controldata against
           the old primary and standby clusters. Verify that the “Latest checkpoint location” values match in
           all clusters. (There will be a mismatch if old standby servers were shut down before the old primary
           or if the old standby servers are still running.) Also, make sure wal_level is not set to minimal in
           the postgresql.conf file on the new primary cluster.

        9. Run pg_upgrade: Always run the pg_upgrade binary of the new server, not the old one.  pg_upgrade
           requires the specification of the old and new cluster's data and executable (bin) directories. You
           can also specify user and port values, and whether you want the data linked instead of copied (the
           default).

           If you use link mode, the upgrade will be much faster (no file copying) and use less disk space, but
           you will not be able to access your old cluster once you start the new cluster after the upgrade.
           Link mode also requires that the old and new cluster data directories be in the same file system.
           (Tablespaces and pg_xlog can be on different file systems.) See pg_upgrade --help for a full list of
           options.

           The --jobs option allows multiple CPU cores to be used for copying/linking of files and to dump and
           reload database schemas in parallel; a good place to start is the maximum of the number of CPU cores
           and tablespaces. This option can dramatically reduce the time to upgrade a multi-database server
           running on a multiprocessor machine.

           For Windows users, you must be logged into an administrative account, and then start a shell as the
           postgres user and set the proper path:

               RUNAS /USER:postgres "CMD.EXE"
               SET PATH=%PATH%;C:\Program Files\PostgreSQL\9.0\bin;

           and then run pg_upgrade with quoted directories, e.g.:

               pg_upgrade.exe
                       --old-datadir "C:/Program Files/PostgreSQL/8.4/data"
                       --new-datadir "C:/Program Files/PostgreSQL/9.0/data"
                       --old-bindir "C:/Program Files/PostgreSQL/8.4/bin"
                       --new-bindir "C:/Program Files/PostgreSQL/9.0/bin"

           Once started, pg_upgrade will verify the two clusters are compatible and then do the upgrade. You can
           use pg_upgrade --check to perform only the checks, even if the old server is still running.
           pg_upgrade --check will also outline any manual adjustments you will need to make after the upgrade.
           If you are going to be using link mode, you should use the --link option with --check to enable
           link-mode-specific checks.  pg_upgrade requires write permission in the current directory.

           Obviously, no one should be accessing the clusters during the upgrade.  pg_upgrade defaults to
           running servers on port 50432 to avoid unintended client connections. You can use the same port
           number for both clusters when doing an upgrade because the old and new clusters will not be running
           at the same time. However, when checking an old running server, the old and new port numbers must be
           different.

           If an error occurs while restoring the database schema, pg_upgrade will exit and you will have to
           revert to the old cluster as outlined in Step 16 below. To try pg_upgrade again, you will need to
           modify the old cluster so the pg_upgrade schema restore succeeds. If the problem is a contrib module,
           you might need to uninstall the contrib module from the old cluster and install it in the new cluster
           after the upgrade, assuming the module is not being used to store user data.

        10. Upgrade Streaming Replication and Log-Shipping standby servers: If you used link mode and have
           Streaming Replication (see Section 25.2.5, “Streaming Replication”, in the documentation) or
           Log-Shipping (see Section 25.2, “Log-Shipping Standby Servers”, in the documentation) standby
           servers, you can follow these steps to quickly upgrade them. You will not be running pg_upgrade on
           the standby servers, but rather rsync on the primary. Do not start any servers yet.

           If you did not use link mode, do not have or do not want to use rsync, or want an easier solution,
           skip the instructions in this section and simply recreate the standby servers once pg_upgrade
           completes and the new primary is running.  Install the new PostgreSQL binaries on standby servers:
           Make sure the new binaries and support files are installed on all standby servers.  Make sure the new
           standby data directories do not exist: Make sure the new standby data directories do not exist or are
           empty. If initdb was run, delete the standby servers' new data directories.  Install custom shared
           object files: Install the same custom shared object files on the new standbys that you installed in
           the new primary cluster.  Stop standby servers: If the standby servers are still running, stop them
           now using the above instructions.  Save configuration files: Save any configuration files from the
           old standbys' configuration directories you need to keep, e.g., postgresql.conf (and any files
           included by it), postgresql.auto.conf, recovery.conf, pg_hba.conf, because these will be overwritten
           or removed in the next step.  Run rsync: When using link mode, standby servers can be quickly
           upgraded using rsync. To accomplish this, from a directory on the primary server that is above the
           old and new database cluster directories, run this on the primary for each standby server:

               rsync --archive --delete --hard-links --size-only --no-inc-recursive old_cluster new_cluster remote_dir

           where old_cluster and new_cluster are relative to the current directory on the primary, and
           remote_dir is above the old and new cluster directories on the standby. The directory structure under
           the specified directories on the primary and standbys must match. Consult the rsync manual page for
           details on specifying the remote directory, e.g.,

               rsync --archive --delete --hard-links --size-only --no-inc-recursive /opt/PostgreSQL/9.5 \
                     /opt/PostgreSQL/9.6 standby.example.com:/opt/PostgreSQL

           You can verify what the command will do using rsync's --dry-run option. While rsync must be run on
           the primary for at least one standby, it is possible to run rsync on an upgraded standby to upgrade
           other standbys, as long as the upgraded standby has not been started.

           What this does is to record the links created by pg_upgrade's link mode that connect files in the old
           and new clusters on the primary server. It then finds matching files in the standby's old cluster and
           creates links for them in the standby's new cluster. Files that were not linked on the primary are
           copied from the primary to the standby. (They are usually small.) This provides rapid standby
           upgrades. Unfortunately, rsync needlessly copies files associated with temporary and unlogged tables
           because these files don't normally exist on standby servers.

           If you have tablespaces, you will need to run a similar rsync command for each tablespace directory,
           e.g.:

               rsync --archive --delete --hard-links --size-only --no-inc-recursive /vol1/pg_tblsp/PG_9.5_201510051 \
                     /vol1/pg_tblsp/PG_9.6_201608131 standby.example.com:/vol1/pg_tblsp

           If you have relocated pg_xlog outside the data directories, rsync must be run on those directories
           too.  Configure streaming replication and log-shipping standby servers: Configure the servers for log
           shipping. (You do not need to run pg_start_backup() and pg_stop_backup() or take a file system backup
           as the standbys are still synchronized with the primary.)

        11. Restore pg_hba.conf: If you modified pg_hba.conf, restore its original settings. It might also be
           necessary to adjust other configuration files in the new cluster to match the old cluster, e.g.,
           postgresql.conf (and any files included by it), postgresql.auto.conf.

        12. Start the new server: The new server can now be safely started, and then any rsync'ed standby
           servers.

        13. Post-Upgrade processing: If any post-upgrade processing is required, pg_upgrade will issue warnings
           as it completes. It will also generate script files that must be run by the administrator. The script
           files will connect to each database that needs post-upgrade processing. Each script should be run
           using:

               psql --username postgres --file script.sql postgres

           The scripts can be run in any order and can be deleted once they have been run.

               Caution
               In general it is unsafe to access tables referenced in rebuild scripts until the rebuild scripts
               have run to completion; doing so could yield incorrect results or poor performance. Tables not
               referenced in rebuild scripts can be accessed immediately.

        14. Statistics: Because optimizer statistics are not transferred by pg_upgrade, you will be instructed
           to run a command to regenerate that information at the end of the upgrade. You might need to set
           connection parameters to match your new cluster.

        15. Delete old cluster: Once you are satisfied with the upgrade, you can delete the old cluster's data
           directories by running the script mentioned when pg_upgrade completes. (Automatic deletion is not
           possible if you have user-defined tablespaces inside the old data directory.) You can also delete the
           old installation directories (e.g., bin, share).

        16. Reverting to old cluster: If, after running pg_upgrade, you wish to revert to the old cluster, there
           are several options:

           •   If the --check option was used, the old cluster was unmodified; it can be restarted.

           •   If the --link option was not used, the old cluster was unmodified; it can be restarted.

           •   If the --link option was used, the data files might be shared between the old and new cluster:

               •   If pg_upgrade aborted before linking started, the old cluster was unmodified; it can be
                   restarted.

               •   If you did not start the new cluster, the old cluster was unmodified except that, when
                   linking started, a .old suffix was appended to $PGDATA/global/pg_control. To reuse the old
                   cluster, remove the .old suffix from $PGDATA/global/pg_control; you can then restart the old
                   cluster.

               •   If you did start the new cluster, it has written to shared files and it is unsafe to use the
                   old cluster. The old cluster will need to be restored from backup in this case.

NOTES

       pg_upgrade does not support upgrading of databases containing these reg* OID-referencing system data
       types: regproc, regprocedure, regoper, regoperator, regconfig, and regdictionary. (regtype can be
       upgraded.)

       All failure, rebuild, and reindex cases will be reported by pg_upgrade if they affect your installation;
       post-upgrade scripts to rebuild tables and indexes will be generated automatically. If you are trying to
       automate the upgrade of many clusters, you should find that clusters with identical database schemas
       require the same post-upgrade steps for all cluster upgrades; this is because the post-upgrade steps are
       based on the database schemas, and not user data.

       For deployment testing, create a schema-only copy of the old cluster, insert dummy data, and upgrade
       that.

       If you are upgrading a pre-PostgreSQL 9.2 cluster that uses a configuration-file-only directory, you must
       pass the real data directory location to pg_upgrade, and pass the configuration directory location to the
       server, e.g., -d /real-data-directory -o '-D /configuration-directory'.

       If using a pre-9.1 old server that is using a non-default Unix-domain socket directory or a default that
       differs from the default of the new cluster, set PGHOST to point to the old server's socket location.
       (This is not relevant on Windows.)

       If you want to use link mode and you do not want your old cluster to be modified when the new cluster is
       started, make a copy of the old cluster and upgrade that in link mode. To make a valid copy of the old
       cluster, use rsync to create a dirty copy of the old cluster while the server is running, then shut down
       the old server and run rsync --checksum again to update the copy with any changes to make it consistent.
       (--checksum is necessary because rsync only has file modification-time granularity of one second.) You
       might want to exclude some files, e.g., postmaster.pid, as documented in Section 24.3.3, “Making a Base
       Backup Using the Low Level API”, in the documentation. If your file system supports file system snapshots
       or copy-on-write file copies, you can use that to make a backup of the old cluster and tablespaces,
       though the snapshot and copies must be created simultaneously or while the database server is down.

SEE ALSO

       initdb(1), pg_ctl(1), pg_dump(1), postgres(1)