If I have a backup, I know I can typically do psql dbname < infile
but if I have an existing database and I want to write the backup on top, is there a simple way?
In other words, I have a database that's currently live, and I have a backup. The database crashed and now it only has a few rows, so I want to add my backup rows to the rows currently in the database.
Related
I have server1 and server2 in my environment, both have db2 v11.1 installed.
I have already done an online tablespaces (TS1, TS2, TS3) incremental backup of my database GS_DB and obtained the below 3 images.
Image1 at timestamp1: 20190215162151 (full online backup of TS1,TS2,TS3)
Image2 at timestamp2: 20190215162254 (incremental online backup of TS1,TS2,TS3)
Image3 at timestamp3: 20190215162725 (incremental online backup of TS1,TS2,TS3)
In server1, suppose I want to restore my db to image2 (20190215162254), I can do:
db2ckrst -d GS_DB -t 20190215162254 -r tablespace
Suggested restore order of images using timestamp 20190215162254 for database gs_db.
====================================================================
restore db gs_db tablespace ( TS1, TS2, TS3 ) incremental taken at 20190215162254
restore db gs_db incremental taken at 20190215162151
restore db gs_db incremental taken at 20190215162254
====================================================================
If I follow the order and restore to the existing GS_DB in server1, it is working fine.
Now I transferred 3 images to server2 and created an empty database GS_DB in server2, then try to use the above command to restore tablespaces TS1,TS2,TS3 to GS_DB in server2:
db2 restore db gs_db2 tablespace ( TS1, TS2, TS3 ) incremental taken at 20190215162254
SQL2560N The table space restore operation failed because the target database is not identical to the source database.
Already stuck at the first command, does it mean we cannot restore tablespace backup image across two different db? Any way I can do it?
Thanks in advance!
Every database has an unique internal identifier called Seed. You can't create another database with the same Seed as the existing one, even you create it with the same name. These databases are different from the DB2's point of view.
Citation from the Restoring to an existing database article:
The database manager assigns the seed when you create the database.
Db2® always uses the seed from the backup image.
You can restore a table space into an existing database only if the table space exists and if the table spaces are the same, meaning that you did not drop
the table space and then re-create it between the backup and the
restore operations.
The database on disk and in the backup image must
be the same.
So, yes, you are not able to restore tablespace backup image across two different db in the way you try.
Read about the Database schema transporting feature.
I have two postgres databases on the same server, a live one and another one which I use as a test database.
Periodically I need to copy my live database (both structure of the tables and their data) into the test one, but everything I've found online only copies table by table. Since I often create new tables in my live db I can't do this, otherwise I'd have to update the job every time.
Anybody knows how can I pull the whole live postgres db into the test postgres one?
Thanks!
You want to use pg_dump and pg_restore.
Example usage would be:
$ pg_dump -Fc <database_name> > dumpfile
$ pg_restore <another_database_name> < dumpfile
If you want to do this for all database you might want to consider pg_dumpall
A bit more can be found in https://www.postgresql.org/docs/current/backup-dump.html
I accidentally dropped original postgres database after installing postgreSQL software. Postgres user is still there, \du superuser. How to recover or recreate original postgres database?
https://www.postgresql.org/docs/current/static/sql-createdatabase.html
just run
create database postgres;
it will create db with default template (which is "template1"). If you did not modify it - it will be same is previous "postgres" db
You can only recover it if you have some previous backup of that database, by restoring that backup and then applying WAL files upto the time when drop database statement was issued.
There is no other way to recover a dropped database.
Using pg_dump I created a backup database and restored it into a new database. The problem is some columns doesn't have the values displayed. Can I use pg_dump with a where clause to populate the new database with the missing values from the back-up database if the id from the back-up database is find in the new database?
I have backups of my postgres database - the entire database instance in a single nightly backup. Is it possible to restore just one of the database from within that backup? Or if I want to access individual databases (for migration or restoring), do I need to change my database backup scheme to do individual dumps?
You can access individual databases from a full database cluster dump in text format (pg_dumpall) by using some text processing like this:
awk '/^\\connect database_name/ {flag=1;print;next}
/^\\connect/ {flag=0}
flag { print }' \
< all_databases.sql \
> database_name.sql
This would get from pg_dumpall file everything between "\connect database_name" and next "\connect". But it is not very efficient.
But I'd recommend dumping every database separately like this:
# Dumping global data (for example roles)
pg_dumpall -g > /var/lib/pgsql/backups/globals.sql
#Dumping indidual databases in tar (uncompressed binary) format
for dbname in
`
psql -qXtc "
select datname from pg_catalog.pg_database
where datname<>'template0'" template1
`
do
pg_dump -b -F t "$dbname" > "/var/lib/pgsql/backups/$dbname.dump"
done
I'm assuming you mean "Can I restore just one database from a pg_dumpall of the entire database cluster?"
Yes, if your backup is "an archive created by pg_dump in one of the non-plain-text formats." - use the "--schema=" option to pg_restore.
On the other hand I'm not sure you're using the correct terminology here - you refer to a DB cluster as "entire database instance"; in the explanation you ask about "database" but in the title you wrote "schema", etc.
Edit: Now, after some deliberation, I believe you have a cluster backup, created with "pg_dumpall". "pg_dumpall" creates only plain-text (SQL-commands) backups. In that case it's not possible to restore only one database (or only one schema from a database).
Then yes, you need to change your backup procedure to backup individual databases using non-plain-text format (--format=custom is the recommended one).
Actually the backup procedure I use on my DB servers does just that.