All but a few existing callers assume without checking that this
function succeeds. While it probably will, that's a poor excuse for
not checking. Let's make it return void and instead throw an error
if it doesn't find the block reference. Callers that actually need
to handle the no-such-block case must now use the underlying function
XLogRecGetBlockTagExtended.
In addition to being a bit less error-prone, this should also serve
to suppress some Coverity complaints about XLogRecGetBlockRefInfo.
While at it, clean up some inconsistency about use of the
XLogRecHasBlockRef macro: make XLogRecGetBlockTagExtended use
that instead of open-coding the same condition, and avoid calling
XLogRecHasBlockRef twice in relevant code paths. (That is,
calling XLogRecHasBlockRef followed by XLogRecGetBlockTag is now
deprecated: use XLogRecGetBlockTagExtended instead.)
Patch HEAD only; this doesn't seem to have enough value to consider
a back-branch API break.
Discussion: https://postgr.es/m/425039.1649701221@sss.pgh.pa.us
Introduce a new GUC recovery_prefetch. When enabled, look ahead in the
WAL and try to initiate asynchronous reading of referenced data blocks
that are not yet cached in our buffer pool. For now, this is done with
posix_fadvise(), which has several caveats. Since not all OSes have
that system call, "try" is provided so that it can be enabled where
available. Better mechanisms for asynchronous I/O are possible in later
work.
Set to "try" for now for test coverage. Default setting to be finalized
before release.
The GUC wal_decode_buffer_size limits the distance we can look ahead in
bytes of decoded data.
The existing GUC maintenance_io_concurrency is used to limit the number
of concurrent I/Os allowed, based on pessimistic heuristics used to
infer that I/Os have begun and completed. We'll also not look more than
maintenance_io_concurrency * 4 block references ahead.
Reviewed-by: Julien Rouhaud <rjuju123@gmail.com>
Reviewed-by: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com> (earlier version)
Reviewed-by: Andres Freund <andres@anarazel.de> (earlier version)
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com> (earlier version)
Tested-by: Tomas Vondra <tomas.vondra@2ndquadrant.com> (earlier version)
Tested-by: Jakub Wartak <Jakub.Wartak@tomtom.com> (earlier version)
Tested-by: Dmitry Dolgov <9erthalion6@gmail.com> (earlier version)
Tested-by: Sait Talha Nisanci <Sait.Nisanci@microsoft.com> (earlier version)
Discussion: https://postgr.es/m/CA%2BhUKGJ4VJN8ttxScUFM8dOKX0BrBiboo5uz1cq%3DAovOddfHpA%40mail.gmail.com
Broke with 5c279a6d35. But looks like it had been half-broken since
70e81861fa, because 'rmid' didn't refer to the current record's rmid anymore,
but to rmid from "Initialize resource managers" - a constant.
Allow extensions to specify a new custom resource manager (rmgr),
which allows specialized WAL. This is meant to be used by a Table
Access Method or Index Access Method.
Prior to this commit, only Generic WAL was available, which offers
support for recovery and physical replication but not logical
replication.
Reviewed-by: Julien Rouhaud, Bharath Rupireddy, Andres Freund
Discussion: https://postgr.es/m/ed1fb2e22d15d3563ae0eb610f7b61bb15999c0a.camel%40j-davis.com
Exclusive-mode backups have been deprecated since 9.6 (when
non-exclusive backups were introduced) due to the issues
they can cause should the system crash while one is running and
generally because non-exclusive provides a much better interface.
Further, exclusive backup mode wasn't really being tested (nor was most
of the related code- like being able to log in just to stop an exclusive
backup and the bits of the state machine related to that) and having to
possibly deal with an exclusive backup and the backup_label file
existing during pg_basebackup, pg_rewind, etc, added other complexities
that we are better off without.
This patch removes the exclusive backup mode, the various special cases
for dealing with it, and greatly simplifies the online backup code and
documentation.
Authors: David Steele, Nathan Bossart
Reviewed-by: Chapman Flack
Discussion: https://postgr.es/m/ac7339ca-3718-3c93-929f-99e725d1172c@pgmasters.nethttps://postgr.es/m/CAHg+QDfiM+WU61tF6=nPZocMZvHDzCK47Kneyb0ZRULYzV5sKQ@mail.gmail.com
Crash recovery on standby may encounter missing directories when
replaying create database WAL records. Prior to this patch, the standby
would fail to recover in such a case. However, the directories could be
legitimately missing. Consider a sequence of WAL records as follows:
CREATE DATABASE
DROP DATABASE
DROP TABLESPACE
If, after replaying the last WAL record and removing the tablespace
directory, the standby crashes and has to replay the create database
record again, the crash recovery must be able to move on.
This patch adds a mechanism similar to invalid-page tracking, to keep a
tally of missing directories during crash recovery. If all the missing
directory references are matched with corresponding drop records at the
end of crash recovery, the standby can safely continue following the
primary.
Backpatch to 13, at least for now. The bug is older, but fixing it in
older branches requires more careful study of the interactions with
commit e6d8069522, which appeared in 13.
A new TAP test file is added to verify the condition. However, because
it depends on commit d6d317dbf6, it can only be added to branch
master. I (Álvaro) manually verified that the code behaves as expected
in branch 14. It's a bit nervous-making to leave the code uncovered by
tests in older branches, but leaving the bug unfixed is even worse.
Also, the main reason this fix took so long is precisely that we
couldn't agree on a good strategy to approach testing for the bug, so
perhaps this is the best we can do.
Diagnosed-by: Paul Guo <paulguo@gmail.com>
Author: Paul Guo <paulguo@gmail.com>
Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Author: Asim R Praveen <apraveen@pivotal.io>
Discussion: https://postgr.es/m/CAEET0ZGx9AvioViLf7nbR_8tH9-=27DN5xWJ2P9-ROH16e4JUA@mail.gmail.com
Invalidate abortedRecPtr and missingContrecPtr after a missing
continuation record is successfully skipped on a standby. This fixes a
PANIC caused when a recently promoted standby attempts to write an
OVERWRITE_RECORD with an LSN of the previously read aborted record.
Backpatch to 10 (all stable versions).
Author: Sami Imseih <simseih@amazon.com>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/44D259DE-7542-49C4-8A52-2AB01534DCA9@amazon.com
Teach xlogreader.c to decode the WAL into a circular buffer. This will
support optimizations based on looking ahead, to follow in a later
commit.
* XLogReadRecord() works as before, decoding records one by one, and
allowing them to be examined via the traditional XLogRecGetXXX()
macros and certain traditional members like xlogreader->ReadRecPtr.
* An alternative new interface XLogReadAhead()/XLogNextRecord() is
added that returns pointers to DecodedXLogRecord objects so that it's
now possible to look ahead in the WAL stream while replaying.
* In order to be able to use the new interface effectively while
streaming data, support is added for the page_read() callback to
respond to a new nonblocking mode with XLREAD_WOULDBLOCK instead of
waiting for more data to arrive.
No direct user of the new interface is included in this commit, though
XLogReadRecord() uses it internally. Existing code doesn't need to
change, except in a few places where it was accessing reader internals
directly and now needs to go through accessor macros.
Reviewed-by: Julien Rouhaud <rjuju123@gmail.com>
Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com>
Reviewed-by: Andres Freund <andres@anarazel.de> (earlier versions)
Discussion: https://postgr.es/m/CA+hUKGJ4VJN8ttxScUFM8dOKX0BrBiboo5uz1cq=AovOddfHpA@mail.gmail.com
In commit 70e81861fa to split xlog.c, I moved the startup code that
updates the state in the control file and prints out the "database
system was not properly shut down" message to the log, but I
accidentally removed the "if (InRecovery)" check around it. As a
result, that message was printed even if the system was cleanly shut
down, also during 'initdb'.
Discussion: https://www.postgresql.org/message-id/3357075.1645031062@sss.pgh.pa.us
This moves the functions related to performing WAL recovery into the new
xlogrecovery.c source file, leaving xlog.c responsible for maintaining
the WAL buffers, coordinating the startup and switch from recovery to
normal operations, and other miscellaneous stuff that have always been in
xlog.c.
Reviewed-by: Andres Freund, Kyotaro Horiguchi, Robert Haas
Discussion: https://www.postgresql.org/message-id/a31f27b4-a31d-f976-6217-2b03be646ffa%40iki.fi
Tom Lane
Alvaro Herrera
David Rowley
Daniel Gustafsson
Thomas Munro
Andres Freund
Jeff Davis
Stephen Frost
Heikki Linnakangas