Thread: pgsql: Implement backup API functions for non-exclusive backups
Implement backup API functions for non-exclusive backups Previously non-exclusive backups had to be done using the replication protocol and pg_basebackup. With this commit it's now possible to make them using pg_start_backup/pg_stop_backup as well, as long as the backup program can maintain a persistent connection to the database. Doing this, backup_label and tablespace_map are returned as results from pg_stop_backup() instead of being written to the data directory. This makes the server safe from a crash during an ongoing backup, which can be a problem with exclusive backups. The old syntax of the functions remain and work exactly as before, but since the new syntax is safer this should eventually be deprecated and removed. Only reference documentation is included. The main section on backup still needs to be rewritten to cover this, but since that is already scheduled for a separate large rewrite, it's not included in this patch. Reviewed by David Steele and Amit Kapila Branch ------ master Details ------- http://git.postgresql.org/pg/commitdiff/7117685461af50f50c03f43e6a622284c8d54694 Modified Files -------------- doc/src/sgml/func.sgml | 48 ++++++--- src/backend/access/transam/xlog.c | 55 +++++----- src/backend/access/transam/xlogfuncs.c | 185 ++++++++++++++++++++++++++++++++- src/backend/catalog/system_views.sql | 2 +- src/backend/replication/basebackup.c | 17 +-- src/include/access/xlog.h | 4 +- src/include/access/xlog_fn.h | 1 + src/include/catalog/catversion.h | 2 +- src/include/catalog/pg_proc.h | 4 +- 9 files changed, 265 insertions(+), 53 deletions(-)
On Tue, Apr 5, 2016 at 2:11 PM, Magnus Hagander <magnus@hagander.net> wrote: > Implement backup API functions for non-exclusive backups > > Previously non-exclusive backups had to be done using the replication protocol > and pg_basebackup. With this commit it's now possible to make them using > pg_start_backup/pg_stop_backup as well, as long as the backup program can > maintain a persistent connection to the database. > > Doing this, backup_label and tablespace_map are returned as results from > pg_stop_backup() instead of being written to the data directory. This makes > the server safe from a crash during an ongoing backup, which can be a problem > with exclusive backups. > > The old syntax of the functions remain and work exactly as before, but since the > new syntax is safer this should eventually be deprecated and removed. > > Only reference documentation is included. The main section on backup still needs > to be rewritten to cover this, but since that is already scheduled for a separate > large rewrite, it's not included in this patch. > > Reviewed by David Steele and Amit Kapila We've typically tried to keep the width of commit messages narrow enough that 'git log' looks OK in an 80-character window; this one is wide enough that it doesn't. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
On Tue, Apr 5, 2016 at 8:35 PM, Robert Haas <robertmhaas@gmail.com> wrote:
On Tue, Apr 5, 2016 at 2:11 PM, Magnus Hagander <magnus@hagander.net> wrote:
> Implement backup API functions for non-exclusive backups
>
> Previously non-exclusive backups had to be done using the replication protocol
> and pg_basebackup. With this commit it's now possible to make them using
> pg_start_backup/pg_stop_backup as well, as long as the backup program can
> maintain a persistent connection to the database.
>
> Doing this, backup_label and tablespace_map are returned as results from
> pg_stop_backup() instead of being written to the data directory. This makes
> the server safe from a crash during an ongoing backup, which can be a problem
> with exclusive backups.
>
> The old syntax of the functions remain and work exactly as before, but since the
> new syntax is safer this should eventually be deprecated and removed.
>
> Only reference documentation is included. The main section on backup still needs
> to be rewritten to cover this, but since that is already scheduled for a separate
> large rewrite, it's not included in this patch.
>
> Reviewed by David Steele and Amit Kapila
We've typically tried to keep the width of commit messages narrow
enough that 'git log' looks OK in an 80-character window; this one is
wide enough that it doesn't.
Huh. It would appear I've somehow screwed up the commit-message-mode that is supposed to warn me about that.
My apologies.
Magnus Hagander <magnus@hagander.net> writes:
> Implement backup API functions for non-exclusive backups
Shouldn't the CF entry for this be closed? The docs rewrite
seems like a separate task.
regards, tom lane
On Wed, Apr 6, 2016 at 6:38 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Magnus Hagander <magnus@hagander.net> writes:
> Implement backup API functions for non-exclusive backups
Shouldn't the CF entry for this be closed? The docs rewrite
seems like a separate task.
It should. I forgot, thanks for the reminder. Done now.