Am using WAL E and trying to restore a postgresql database i get the error WAL file is from different database system: WAL file database system identifier is 6422218584094261886, pg_control database system identifier is 6338745400937582833
How can i force the postgresql database to use the database identifier of the WAL archive or force WAL archive to use the Database system identifier of the database
To restore the WAL files you will need your original base-backup and all the WAL files from that point forwards. The WAL files themselves list the changes to a base backup.
Did you move the pg data dir while the database was still running?
Had the same problem when migrating from one server node to the other, moving the postgres data dir with scp to the other node. When starting the docker container on the new node, i got this error in docker log -f. It turned out that i was copying the dirs while the postgres docker container on the source node was still running.
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I am trying to perform a Point-In-Time Recovery using the WAL_ARCHIVE process. The archive command is added to the postgresql.conf file and I can see the WAL being archived in the backup-archive directory. When I try to start the service I get PANIC: could not locate a valid checkpoint record
I am using the below step-by-step process.
low level api basebackup
SELECT pg_start_backup('label', true, false);
copying the data directory of my cluster
tar -zcvpf basebkPostgres20230110New.tgz /PostgreSQL/13/data
closing my basebackup
SELECT * FROM pg_stop_backup(false, true);
Stopping the postgres service
Removing the current's cluster data directory
Restoring the backed up data directory
Removing the contents of the pg_wal directory
Setting the restore_command in the postgresql.conf file
Starting the postgres service
You forgot the backup_label file and recovery.signal. You have to capture the result of pg_stop_backup (or pg_backup_stop from v15 on) and create backup_label from the contents. That file has to be in the restored data directory. Also, you have to create recovery.signal in the data directory, so that PostgreSQL starts in archive recovery mode and reads your restore_command.
Without restore_command, PostgreSQL uses the WAL in pg_wal, which is empty. Without backup_label, PostgreSQL thinks that it can recover from the checkpoint indicated by the control file pg_control. Even if that worked, the result would be a corrupted database, since you have to recover from the start of the backup.
recovery.signal is documented here (step 7), and backup_label is documented here (step 4).
I try to configure backuping database in postgresql with pg_basebackup and WAL logs.
For now I created full backup once a week and want to backup wal logs too. But, as I understand, posgresql writes them all the time. So, how can I copy them and be shure that they are not corrupted?
Thanks
You set archive_command to a shell command that copies the WAL file to a safe archive location, so that burden is mostly on you.
When PostgreSQL runs archive_command, it assumes that the WAL file is not corrupted. Only a PostgreSQL bug or a bug in the storage system could cause a corrupted WAL segment.
There is no better protection against PostgreSQL bugs than always running the latest bugfix release, and you can invest in storage hardware that will at least detect failure.
You can also write your archive_command with a certain amount of paranoia, e.g. by comparing the md5sum of the WAL segment and its archive copy.
Another idea is to write two copies of the WAL file to different storage systems.
I am not a DBA but i am using postgresql for production server and i am using postgresql 10 database. I am using Bigsql and i started replication of my production server to other server and on replication server everything is working but on my production server their is no space left. And after du command on my production server i am getting that pg_wal folder have 17 gb file and each file is of 16 mb size.
After some google search i change my postgresql.conf file as:
wal_level = logical
archive_mode = on
archive_command = 'cp -i %p /etc/bigsql/data/pg10/pg_wal/archive_status/%f'
i install postgresql 10 from Bigsql and did above changes.
After changes the dir /pg_wal/archive_status had 16 gb of log. So my question is that should i delete them manually or i have to wait for system delete them automatically.
And is that if i write archive_mode to on should that wal file getting removed automatically??
Thanks for your precious time.
This depends on how you do your backups and whether you'd ever need to restore the database to some point in time.
Only a full offline filesystem backup (offline meaning with database turned off) or an on-line logical backup with pg_dumpall will not need those files for a restore.
You'd need those files to restore a filesystem backup created while the database is running. Without them the backup will fail to restore. Though there exist backup solutions that copy needed WAL files automatically (like Barman).
You'd also need those files if your replica database will ever fall behind the master for some reason. Or you'd need to restore the database to some past point-in-time.
But these files compress pretty well - should be less than 10% size after compression - you can write your archive_command to compress them automatically instead of just copying.
And you should delete them eventually from the archive. I'd recommend to not delete them until they're at least a month old and also at least 2 full successful backups are done after creating them.
I have a postgre database DATA1 in table space location D:\tbl_DATA1. We use OS backup restore tool copy the the D:\tbl_DATA1 to a target machine C:\tbl_DATA1. Is it possible for recreate the database from this folder in the second mahcine?
https://www.postgresql.org/docs/current/static/backup-file.html
An alternative backup strategy is to directly copy the files that
PostgreSQL uses to store the data in the database
and later two restrictions mentionned
The database server must be shut down in order to get a usable backup.
You should resotore the whole PGDATA direcotory, not the certain individual tables or databases from their respective files or directories.
So yes - it is a common practice to shutdown the PostgreSQL, copy PGDATA directory to other machine and start Postgres in order to get the cluser copy. But it is done cluster level - not tablespace as you mention or database - the whole data_directory should be copied.
So no - copying the tablespace directory and trying to hack the db to add a tablespace will fail.
What I am trying to accomplish is a recovery using a continuous archive backup.
I am running a vm of CentOS 6.8 and Postgres 9.1 Postgres 9.1 is the same as the DB that I am pulling from.
I installed Postgres and initialized the DB, started up fine.
Then, following these directions: https://www.postgresql.org/docs/9.3/static/continuous-archiving.html
Stopped the destination pSQL server (as root: service postgresql-9.1 stop)
Copied the destination cluster data folder to the side (as postgres)
Removed the cluster data files (as postgres)
Copied in my source data folder (as postgres)
Copied WAL files into a clean pg_xlog folder under the data folder (as postgres)
Created a recovery.conf file which contained:
restore_command = 'cp /var/lib/pgsql/database_sample_backup/wal_archives/0A/%f %p'
This being another location for the WAL files other than the copy I placed in pg_xlog (was not sure if I needed both)
But when I attempt to restart my server, it fails. (as root: service postgresql-9.1 start)
My pgstartup.log at one point spit out "runuser: cannot set groups: Operation not permitted" but it doesn't consistently do this with every attempt to start.
I've also tried turning off archiving and replication directive in postgres.conf (so that it can run stand alone) and tried copying over the pg_hba.conf from the new DB I had created to see if they would resolve the issue. Neither did.
I've also done a netstat -ntap | grep 5432 which confirmed that I don't have anything else running on the port.
What else can I provide in the form of details, and what else my I attempt in this restoration process.
Thank you for your help!