I was working with postgresql, and suddenly, this stop it. I stoped service, but when i try start it, never i can do it.
service postgresql start FAIL
don't have a backup, and with pg_dump is imposible.
pg_dump -i -h localhost -p 5432 -U postgres -F c -b -v -f "/mibase.backup" mydatabase
which is the best form to do a backup?
I had a lot of trouble with PostgreSQL 9.0.2 under Windows. The service would just stop every couple of days. I never had trouble restarting it, though. Never had to restart the Windows server to restart the PostgreSQL service.
With the PostgreSQL service shut down, you can copy the database files.
If you're not on the most current release of your version, you might try installing a more recent minor version. Postgresql doesn't mind running multiple versions on the same server, although they each have to listen on a different port.
The minor version number is the third digit. Above, the major version is "9.0". If you're running 9.0.2, you want 9.0.[a number greater than 2]. Why?
"Minor releases never change the internal storage format and are always compatible with earlier and later minor releases of the same major version number, e.g., 8.4.2 is compatible with 8.4, 8.4.1 and 8.4.6." (Upgrading a PostgreSQL Cluster)
So a minor version upgrade, listening on a different port, and pointing to your old data directory might let you make a SQL dump. A SQL dump can be restored to any version.
A minor version upgrade pointing to a new data directory should be able to read files copied at the filesystem level. (Paragraph 2, way above.)
Related
I would like to switch from postgres 9.6 to version 14 which runs on Ubuntu 21.04. I have a cluster with 3 databases.
I would like to know what is the difference between upgrading with pg_upgrade and pg_upgradecluster? Which one is faster and safer?
pg_upgrade is a tool from Postgresql itself that will operate on a single database (folder).
pg_upgradecluster however is a wrapper from your operating system (= Ubuntu) to pg_upgrade or pg_dump/pg_restore. In addition to very conveniently upgrading your database, it will also do some housekeeping like moving the config files to the correct folder in /etc/postgres/ .
So, if you have set up your database by pg_createcluster and it is hence listed by pg_lsclusters, I'd strongly recommend using pg_upgradecluster to upgrade it.
In terms of "faster vs. safer", be sure to read about the various options on the manpage.
If you can take a reliable backup (e.g. snapshot), you can safely use the -m upgrade --link option which will be fastest and allow for a very short downtime (depending on database size and resources, but I've recently upgraded a 700GB database in ~25 seconds).
The safest option of course is not using pg_upgrade, but the default pg_dump/pg_restore method, which will shut down your original database and copy the data to a new database in a new location (= it will use at approx. twice the space, at least temporarily until you decide to delete the original folder).
What is version number supposed to represent in this CLI command: pg_ctl -D /usr/local/var/postgres[VERSION NUMBER HERE] start ?
VERSION NUMBER HERE usually refers to the major version number (not patch/minor release).
So if you have version 10.3 installed, it should refer to 10
Note that in 9.6 and earlier, major versions had two digits, followed by a patch version (example: 9.5.4 -- major version is 9.5, minor version is 4).
However, what's more important than the version is what folder exists at /usr/local/var -- You could have a data directory that has no versions (i.e., you can do initdb /tmp/foo and all your data will go into foo, and pg_ctl -D /tmp/foo start should get your database started). A good rule of thumb (though there are situations where this fails) is to look for the directory containing postgresql.conf, and that directory is what you would pass as an argument to pg_ctl -D <dir> start
Disclosure: I am an EnterpriseDB (EDB) employee
By including the version number of the Postgres version in the name of the data directory allows you to have multiple clusters (=instances) running at the same time using the same binaries.
Including the version number in the name of the data directory is not mandatory though, and whether it was done during installation or not depends on which Linux distribution you are using. Every distribution does this slightly differently.
But typically you don't start Postgres through pg_ctl but through the systems "service manager", e.g. systemctl or service depending on the Linux distribution. You can check the service definition where the exact location of the data directory is.
I am trying upgrade postgres-9.3 to postgres-10 with database size around 165GB. I am using "sudo pg_upgradecluster 9.3 main" to do so but it's taking around 8hours which is way too much downtime for my live webapp. Any suggestions to make it better with lesser downtime and faster.
You can tell pg_upgradecluster to use Postgres' pg_upgrade tool with the --link option which should then finish in minutes rather than hours:
pg_upgradecluster --method=upgrade --link ......
Note that --link will not copy your data, so the only way to revert the upgrade is to restore your last backup to a 9.3 installation.
Quote from the Postgres manual
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.
...
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.
I need to use the new jsonb field in postgres so I decided to upgrade to 9.5 in my ununtu 16.04 LTS. I followed this tutorial , but when it gets to the command pg_upgradecluster 9.3 main, I get the error that cluster configuration already exists. I checked other tutorials and found that I could get the list of clusters with pg_lsclusters. But the command always shows only the 9.3 cluster. Any attempt to create the 9.5 cluster always results to cluster configuration already exists. I purged the 9.5 and installed again multiple times but the same result. At last I decided to purge all the postgres installations I have after backing up my 9.3 cluster with pg_dumpall.
Now I have decided to install the 9.5 freshly but I still get the same thing. When I install pg_lsclusters shows nothing and after starting postgres psql always returns psql: could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
Right now I'm so tired and frustrated. Please if anyone has any possible solution or suggestion, help
The problem seemed to be from the version 9.5 in the postgres repositories. I installed 9.6 and everything worked like magic. Had I known there was a stable 9.6 earlier, I wouldn't have wasted 6 hours of my life in something I could have done for 10 minutes. Anyway, I'm happy I have have a working postgres with jsonb field
I have upgraded from 9.2 to 9.3 successfully on ubuntu. However,
/etc/init.d/postgresql start
starts both 9.2 and 9.3
Although the above command can accept that the version number and successfully starts and stops each one, is there any method I can use to make this command start 9.3 only.
The reason is that, I am not able to reboot the system now, but I am afraid when it is rebooted both servers can start.
My short term solution is to adjust the port numbers to make my application use 9.3 database. However, I would like to learn about more permanent and robust solutions.
Thanks in advance,
Steve
Ubuntu uses pg_wrapper to manage PostgreSQL installs. See the Ubuntu PostgreSQL wiki page.
You'll want to pg_dropcluster the 9.2 cluster, if you wish to actually destroy the old data. Or un-install PostgreSQL 9.2. Or modify the config file (don't remember the name right now) in /etc/postgresql/9.2/ that controls whether Pg starts or not. It's called something like start.conf or pg_ctl.conf or something.
You may also want to reverse the configured ports so your new 9.3 runs on 5432 and your not-started-by-default 9.2 tuns on 5433. That is in postgresql.conf.
Steve Harman's response worked perfectly for me, too:
Thanks for the response. In the /etc/postgresql/9.2/main/ directory, there is start.conf. If you change the single line in that file from 'auto' to 'disabled' then, /etc/init.d/postgresql start will not start 9.2. – Steve Harman Jan 1 at 16:55
On the other hand, just fyi, the command output is that both versions of the server are starting (which is not true and is coming from the service starting scripts)
user#server:/etc/postgresql/9.3/main$ sudo service postgresql start
* Starting PostgreSQL 9.1 database server
...done.
* Starting PostgreSQL 9.3 database server
...done.