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Re: Un successful Restoration of DATA using WAL files

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On Mon, 2009-10-19 at 07:18 -0700, Mitesh51 wrote:
> I am unable to restore data with the use of WAL files by following procedure.
> 
> I have done following changes in postgres.conf to enable WAL archiving...
> 
> archive_mode = on		# allows archiving to be done
> archive_command = 'copy "%p" "C:\\archivedir\\%f"'	
> 
> I have one database(built in) postgres. I create one table student in it.
> and take full backup(only of a single database & I am not copying complete
> data dir..) @ 12:40 pm with the 
> 
> pg_dump.exe -h localhost -p 5432 -U postgres -f C:\test.sql postgres

Any comments from readers on the following suggestion of changes to the
PITR docs at:

http://www.postgresql.org/docs/current/interactive/continuous-archiving.html

        
        User misunderstandings on the pgsql-general mailing list suggest
        that a clear and prominent warning needs to be added to this
        page to prevent people from trying to combine a pg_dump base
        backup with WAL archiving. People are failing to understand that
        the base backup must be a file-system-level copy taken after
        calling pg_start_backup() .
        
        Suggested changes:
        
        "maintains a write ahead log" -> "maintains a block-level write
        ahead log" in the first paragraph.
        
        "we can combine a file-system-level backup" -> 
        "we can combine a file-system-level backup of the data directory
        (<b>not</b> a pg_dump backup)"
        
        Also, somewhere in the introductory section, something like this
        would be good:
        
        "IMPORTANT: WAL archiving and PITR cannot be used with an
        SQL-level base backup taken with pg_dump. See "Making a Base
        Backup" below for the correct method of backing up your database
        for WAL archiving and PITR. See "Caveats" for details."
        
        In "Caveats":
        
        "You can't use pg_dump to make a base backup, restore that to a
        different cluster or a new database in the original cluster,
        then apply archived WAL files to it. WAL archiving records a
        history of changes to the database cluster at a very low level,
        rather than recording anything like SQL commands. The WAL files
        essentially record sequences of writes of byte sequences to
        offsets within files in the cluster. A new cluster (or a new
        database created in the original cluster by CREATE DATABASE)
        will have a different layout in its files, so the WAL archives
        don't make any sense to apply to the new cluster."


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