What actually Happend:
Running windows 7 on my system and system was shutdown due to power failure. when system restarted, I opened PostgreSQL and all my databases were deleted.
I checked logs and there were some entries
Database system was intrupted ; last known up at (dateTime)
Database system was not properly shutdown; automatic recovery in progress
Record with zero length at 0/C9B92168
Redo is not required
Can anybody tell me how can i recover my databases, as I don't have restore point.
Related
A slave database was set up some time ago for the purpose of backing up or replicating a remote database. However I can no longer write to the database using a Delphi based ETL (the ETL works for another database pair, but to date has never been used for this particular pair). The replication database was setup by somebody else who has since left the company. I am reasonably sure this has been setup as a replication database, however the employee who has since left told me that replication never worked for unrelated reasons. Using the ETL we can (using SQL queries) read from the one database, and write back to the replication database, Or should be able to, as it is currently read only.
I have tried:
Maintenance such as VACUUM
Attempt to drop tables and the entire database
Restore a full backup from the master database
None of these work, and I am told the database is read-only.
I have looked at postgresql.conf and see that hot_standby is checked, so I think (but am not 100% certain) that the database is in some sort of replication mode (I've never touched replication as supported by Postgres, so I wouldn't know).
I have checked permissions in pg_hba.conf and see there are some credentials in there for replication. I am not sure whether this activates "replication mode" for the database, or simply means these credentials are for replication only.
I have been through months worth of log files (This has not been working since our IT department upgraded the entire network about 5 months ago). I see the log file contents seen below, repeated over and over with nothing else for months. Note the IP address shown below is listed in the pg_hba.conf file, so credentials are valid.
The database is in recovery mode, as I have found by using:
select pg_is_in_recovery();
This explains to me why it's read only, but why can I not restore databases, or just simply dump the entire database and start again (it's a backup so losing/restoring it is not an issue)?
I was tempted to try modifying the recovery.conf file (which exists) but I read/believe that once recovery has been initiated (which in my case it has) modifying the file will have no effect.
I'm using a legacy version of Postgres: 9.2.9
Any help here would be greatly appreciated, as I have been working solidly on this for more than a day now.
Log File entry (sample):
FATAL: could not connect to the primary server:
FATAL: no pg_hba.conf entry for replication connection from host "192.168.20.2", user "postgres", SSL off
FATAL: could not connect to the primary server: server closed the connection unexpectedly
This probably means the server terminated abnormally before or while processing the request.
A couple of options would work for me:
Convert the database from being a read-only replication database, to a standard read/write database or
Dump/drop the entire database so I can create a new one with write capabilities.
It looks like the two database clusters have been set up for replication, but configuration changes on one of the machines broke the replication (changed pg_hba.conf on the primary, changed IP addresses, …).
Here is the way to your desired solutions:
Bringing the standby out of recovery mode: Run
/path/to/pg_ctl promote -D /path/to/data/directory
on the standby as operating system user postgres.
Nuking the standby: Remove the data directory on the standby with rm -rf (or the equivalent on your operating system). Kill all PostgreSQL processes.
Then use initdb to create a new database cluster in the same location.
I have installed postgresql on windows 10 on usb disk.
Every day when i start my pc in work from sleep and plug in the disk again then trying to start postgresql i get this error:
FATAL: the database system is starting up
The service starts with following command:
E:\PostgresSql\pg96\pgservice.exe "//RS//PostgreSQL 9.6 Server"
It is the default one.
logs from E:\PostgresSql\data\logs\pg96
2019-02-28 10:30:36 CET [21788]: [1-1] user=postgres,db=postgres,app=[unknown],client=::1 FATAL: the database system is starting up
2019-02-28 10:31:08 CET [9796]: [1-1] user=postgres,db=postgres,app=[unknown],client=::1 FATAL: the database system is starting up
I want this start up to happen faster.
When you commit data to a Postgres database, the only thing which is immediately saved to disk is the write-ahead log. The actual table changes are only applied to the in-memory buffers, and won't be permanently saved to disk until the next checkpoint.
If the server is stopped abruptly, or if it suddenly loses access to the file system, then everything in memory is lost, and the next time you start it up, it needs to resort to replaying the log in order to get the tables back to the correct state (which can take quite a while, depending on how much has happened since the last checkpoint). And until it's finished, any attempt to use the server will result in FATAL: the database system is starting up.
If you make sure you shut the server down cleanly before unplugging the disk - giving it a chance to set a checkpoint and flush all of its buffers - then it should be able to start up again more or less immediately.
What is the expected behavior for postgresql processes when system time is changed?
For eg: A case is seen with postgres autovacuum process that, it is not working after time has been changed and only solution is to restart the Database.
I have three different databases for my different environments (hsprd, hstst,hstrn). hsprd is my production environment with live data.
Every so often, a request comes through to restore production data to hstrn or hstst. I typically run this command (after stopping, then dropping the db):
db2 restore db hsprd taken at 20140331180002 to /dbs into hstrn newlogpath /dbs/log/hstrn without rolling forward;
When running this, I receive this message:
SQL2537N Roll-forward is required following the Restore.
Could someone advise how to fix this?
Thanks.
edit: My backups are here:
(/home/dbtmp/backups)> ll
total 22791416
-rwxrwxr-x 1 hsprd cics 11669123072 Mar 31 18:03 HSPRD.0.hsprd.NODE0000.CATN0000.20140331180002.001
After restoring my database and omitting without rolling forward, I receive this message when trying to query the database:
SQL1117N A connection to or activation of database "HSTRN" cannot be made
because of ROLL-FORWARD PENDING. SQLSTATE=57019
When I try to rollforward, with this command, I receive this response:
(/home/dbtmp/backups)> db2 rollforward db hstrn to end of backup and complete;
SQL4970N Roll-forward recovery on database "HSTRN" cannot reach the specified
stop point (end-of-log or point-in-time) on database partition(s) "0".
Roll-forward recovery processing has halted on log file "S0006353.LOG".
The first error suggests that you are restoring an online backup, which must be rolled forward. Alternatively, use an offline backup image, then you can include the without rolling forward option.
The second error means that you need to issue the ROLLFORWARD command before you can use the database restored from an online backup.
Finally the third error means that the ROLLFORWARD command is unable to find the logs required for it to succeed. Assuming the logs are included in the backup image, you'll need to specify the LOGTARGET option on the RESTORE command to extract them, presumably to the NEWLOGPATH location.
My company's website uses a PostgreSQL database. In our data center we have a master DB and a few read-only slave DB's, and we use Londiste for continuous replication between them.
I would like to setup another read-only slave DB for reporting purposes, and I'd like this slave to be in a remote location (outside the data center). This slave doesn't need to be 100% up-to-date. If it's up to 24 hours old, that's fine. Also, I'd like to minimize the load I'm putting on the master DB. Since our master DB is busy during the day and idle at night, I figure a good idea (if possible) is to get the reporting slave caught up once each night.
I'm thinking about using log shipping for this, as described on
http://www.postgresql.org/docs/8.4/static/continuous-archiving.html
My plan is:
Setup WAL archiving on the master DB
Produce a full DB snapshot and copy it to the remote location
Restore the DB and get it caught up
Go into steady state where:
DAYTIME -- the DB falls behind but people can query it
NIGHT -- I copy over the day's worth of WAL files and get the DB caught up
Note: the key here is that I only need to copy a full DB snapshot one time. Thereafter I should only have to copy a day's worth of WAL files in order to get the remote slave caught up again.
Since I haven't done log-shipping before I'd like some feedback / advice.
Will this work? Does PostgreSQL support this kind of repeated recovery?
Do you have other suggestions for how to set up a remote semi-fresh read-only slave?
thanks!
--S
Your plan should work.
As Charles says, warm standby is another possible solution. It's supported since 8.2 and has relatively low performance impact on the primary server.
Warm Standby is documented in the Manual: PostgreSQL 8.4 Warm Standby
The short procedure for configuring a
standby server is as follows. For full
details of each step, refer to
previous sections as noted.
Set up primary and standby systems as near identically as possible,
including two identical copies of
PostgreSQL at the same release level.
Set up continuous archiving from the primary to a WAL archive located
in a directory on the standby server.
Ensure that archive_mode,
archive_command and archive_timeout
are set appropriately on the primary
(see Section 24.3.1).
Make a base backup of the primary server (see Section 24.3.2), and load
this data onto the standby.
Begin recovery on the standby server from the local WAL archive,
using a recovery.conf that specifies a
restore_command that waits as
described previously (see Section
24.3.3).
To achieve only nightly syncs, your archive_command should exit with a non-zero exit status during daytime.
Additional Informations:
Postgres Wiki about Warm Standby
Blog Post Warm Standby Setup
9.0's built-in WAL streaming replication is designed to accomplish something that should meet your goals -- a warm or hot standby that can accept read-only queries. Have you considered using it, or are you stuck on 8.4 for now?
(Also, the upcoming 9.1 release is expected to include an updated/rewritten version of pg_basebackup, a tool for creating the initial backup point for a fresh slave.)
Update: PostgreSQL 9.1 will include the ability to pause and resume streaming replication with a simple function call on the slave.