File based Incremental backup v7

Il 27/01/15 10:25, Giuseppe Broccolo ha scritto:> Hi Marco,
>
> On 16/01/15 16:55, Marco Nenciarini wrote:
>> On 14/01/15 17:22, Gabriele Bartolini wrote:
>> >
>> > My opinion, Marco, is that for version 5 of this patch, you:
>> >
>> > 1) update the information on the wiki (it is outdated - I know you have
>> > been busy with LSN map optimisation)
>>
>> Done.
>>
>> > 2) modify pg_basebackup in order to accept a directory (or tar
file) and
>> > automatically detect the LSN from the backup profile
>>
>> New version of patch attached. The -I parameter now requires a backup
>> profile from a previous backup. I've added a sanity check that forbid
>> incremental file level backups if the base timeline is different from
>> the current one.
>>
>> > 3) add the documentation regarding the backup profile and pg_basebackup
>> >
>>
>> Next on my TODO list.
>>
>> > Once we have all of this, we can continue trying the patch. Some
>> > unexplored paths are:
>> >
>> > * tablespace usage
>>
>> I've improved my pg_restorebackup python PoC. It now supports
tablespaces.
>
> About tablespaces, I noticed that any pointing to tablespace locations
> is lost during the recovery of an incremental backup changing the
> tablespace mapping (-T option). Here the steps I followed:
>
>   * creating and filling a test database obtained through pgbench
>
>     psql -c "CREATE DATABASE pgbench"
>     pgbench -U postgres -i -s 5 -F 80 pgbench
>
>   * a first base backup with pg_basebackup:
>
>     mkdir -p backups/$(date '+%d%m%y%H%M')/data && pg_basebackup -v -F
p -D backups/$(date '+%d%m%y%H%M')/data -x
>
>   * creation of a new tablespace, alter the table "pgbench_accounts" to
>     set the new tablespace:
>
>     mkdir -p /home/gbroccolo/pgsql/tbls
>     psql -c "CREATE TABLESPACE tbls LOCATION
'/home/gbroccolo/pgsql/tbls'"
>     psql -c "ALTER TABLE pgbench_accounts SET TABLESPACE tbls" pgbench
>
>   * Doing some work on the database:
>
>     pgbench -U postgres -T 120 pgbench
>
>   * a second incremental backup with pg_basebackup specifying the new
>     location for the tablespace through the tablespace mapping:
>
>     mkdir -p backups/$(date '+%d%m%y%H%M')/data backups/$(date
'+%d%m%y%H%M')/tbls && pg_basebackup -v -F p -D backups/$(date
'+%d%m%y%H%M')/data -x -I backups/2601151641/data/backup_profile -T
/home/gbroccolo/pgsql/tbls=/home/gbroccolo/pgsql/backups/$(date
'+%d%m%y%H%M')/tbls
>
>   * a recovery based on the tool pg_restorebackup.py attached in
>     http://www.postgresql.org/message-id/54B9428E.9020001@2ndquadrant.it
>
>     ./pg_restorebackup.py backups/2601151641/data
backups/2601151707/data /tmp/data -T
/home/gbroccolo/pgsql/backups/2601151707/tbls=/tmp/tbls
>
> In the last step, I obtained the following stack trace:
>
> Traceback (most recent call last):
>   File "./pg_restorebackup.py", line 74, in <module>
>     shutil.copy2(base_file, dest_file)
>   File
"/home/gbroccolo/.pyenv/versions/2.7.5/lib/python2.7/shutil.py", line
130, in copy2
>     copyfile(src, dst)
>   File
"/home/gbroccolo/.pyenv/versions/2.7.5/lib/python2.7/shutil.py", line
82, in copyfile
>     with open(src, 'rb') as fsrc:
> IOError: [Errno 2] No such file or directory:
'backups/2601151641/data/base/16384/16406_fsm'
>
>
> Any idea on what's going wrong?
>

I've done some test and it looks like that FSM nodes always have
InvalidXLogRecPtr as LSN.

Ive updated the patch to always include files if all their pages have
LSN == InvalidXLogRecPtr

Updated patch v7 attached.

Regards,
Marco

--
Marco Nenciarini - 2ndQuadrant Italy
PostgreSQL Training, Services and Support
marco.nenciarini@2ndQuadrant.it | www.2ndQuadrant.it