The displayed sendtime and receipttime were always exactly equal, because
somebody forgot that timestamptz_to_str returns a static buffer (thereby
simplifying life for most callers, at the cost of complicating it for those
who need two results concurrently). Apply the same pstrdup solution used
by the other call sites with this issue. Back-patch to 9.2 where the
faulty code was introduced. Per bug #9849 from Haruka Takatsuka, though
this is not exactly his patch.
Possibly we should change timestamptz_to_str's API, but I wouldn't want
to do so in the back branches.
With this in place, a session blocking behind another one because of
tuple locks will get a context line mentioning the relation name, tuple
TID, and operation being done on tuple. For example:
LOG: process 11367 still waiting for ShareLock on transaction 717 after 1000.108 ms
DETAIL: Process holding the lock: 11366. Wait queue: 11367.
CONTEXT: while updating tuple (0,2) in relation "foo"
STATEMENT: UPDATE foo SET value = 3;
Most usefully, the new line is displayed by log entries due to
log_lock_waits, although of course it will be printed by any other log
message as well.
Author: Christian Kruse, some tweaks by Álvaro Herrera
Reviewed-by: Amit Kapila, Andres Freund, Tom Lane, Robert Haas
On clean shutdown, walsender waits for all WAL to be replicated to a standby,
and exits. It determined whether that replication had been completed by
checking whether its sent location had been equal to a standby's flush
location. Unfortunately this condition never becomes true when the standby
such as pg_receivexlog which always returns an invalid flush location is
connecting to walsender, and then walsender waits forever.
This commit changes walsender so that it just checks a standby's write
location if a flush location is invalid.
Back-patch to 9.1 where enough infrastructure for this exists.
In order for this to work, walsenders need the optional ability to
connect to a database, so the "replication" keyword now allows true
or false, for backward-compatibility, and the new value "database"
(which causes the "dbname" parameter to be respected).
walsender needs to loop not only when idle but also when sending
decoded data to the user and when waiting for more xlog data to decode.
This means that there are now three separate loops inside walsender.c;
although some refactoring has been done here, this is still a bit ugly.
Andres Freund, with contributions from Álvaro Herrera, and further
review by me.
In b89e151054 I had assumed it was ok to use anonymous unions as
struct members, but while a longstanding extension in many compilers,
it's only been standardized in C11.
To fix, remove one of the anonymous unions which tried to hide some
implementation specific enum values and give the other a name. The
latter unfortunately requires changes in output plugins, but since the
feature has only been added a few days ago...
Andres Freund
If walsender doesn't hear from the client for the time specified by
wal_sender_timeout, it will conclude the connection or client is dead, and
disconnect. When half of wal_sender_timeout has elapsed, it sends a ping
to the client, leaving it the remainig half of wal_sender_timeout to
respond. However, it only checked if half of wal_sender_timeout had elapsed
when it was about to sleep, so if it was busy sending WAL to the client for
long enough, it would not send the ping request in time. Then the client
would not know it needs to send a reply, and the walsender will disconnect
even though the client is still alive. Fix that.
Andres Freund, reviewed by Robert Haas, and some further changes by me.
Backpatch to 9.3. Earlier versions relied on the client to send the
keepalives on its own, and hence didn't have this problem.
I changed the loop in 9.3 to use "goto send_failure" instead of "break" on
errors, but I missed this one case. It was a relatively harmless bug: if
the flush fails once it will most likely fail again as soon as we try to
flush the output again. But it's a bug nevertheless.
Report and fix by Andres Freund.
This feature, building on previous commits, allows the write-ahead log
stream to be decoded into a series of logical changes; that is,
inserts, updates, and deletes and the transactions which contain them.
It is capable of handling decoding even across changes to the schema
of the effected tables. The output format is controlled by a
so-called "output plugin"; an example is included. To make use of
this in a real replication system, the output plugin will need to be
modified to produce output in the format appropriate to that system,
and to perform filtering.
Currently, information can be extracted from the logical decoding
system only via SQL; future commits will add the ability to stream
changes via walsender.
Andres Freund, with review and other contributions from many other
people, including Álvaro Herrera, Abhijit Menon-Sen, Peter Gheogegan,
Kevin Grittner, Robert Haas, Heikki Linnakangas, Fujii Masao, Abhijit
Menon-Sen, Michael Paquier, Simon Riggs, Craig Ringer, and Steve
Singer.
Because of the new SLOT clause in the START_REPLICATION command, it's
possible for the command to end up too long for the old maximum buffer
length.
Andres Freund
Additional non-security issues/improvements spotted by Coverity.
In backend/libpq, no sense trying to protect against port->hba being
NULL after we've already dereferenced it in the switch() statement.
Prevent against possible overflow due to 32bit arithmitic in
basebackup throttling (not yet released, so no security concern).
Remove nonsensical check of array pointer against NULL in procarray.c,
looks to be a holdover from 9.1 and earlier when there were pointers
being used but now it's just an array.
Remove pointer check-against-NULL in tsearch/spell.c as we had already
dereferenced it above (in the strcmp()).
Remove dead code from adt/orderedsetaggs.c, isnull is checked
immediately after each tuplesort_getdatum() call and if true we return,
so no point checking it again down at the bottom.
Remove recently added minor error-condition memory leak in pg_regress.
A new MAX_RATE option allows imposing a limit to the network transfer
rate from the server side. This is useful to limit the stress that
taking a base backup has on the server.
pg_basebackup is now able to specify a value to the server, too.
Author: Antonin Houska
Patch reviewed by Stefan Radomski, Andres Freund, Zoltán Böszörményi,
Fujii Masao, and Álvaro Herrera.
The functions in slotfuncs.c don't exist in any released version,
but the changes to xlogfuncs.c represent backward-incompatibilities.
Per discussion, we're hoping that the queries using these functions
are few enough and simple enough that this won't cause too much
breakage for users.
Michael Paquier, reviewed by Andres Freund and further modified
by me.
The temporary statistics files don't need to be included in the backup
because they are always reset at the beginning of the archive recovery.
This patch changes pg_basebackup so that it skips all files located in
$PGDATA/pg_stat_tmp or the directory specified by stats_temp_directory
parameter.
Remove unused copy-and-pasted macro definitions, and improve formatting
of recently-added productions.
I got interested in this because buildfarm member protosciurus has been
crashing in "bison repl_gram.y" since commit 858ec11. It's a long shot
that this will fix that, though maybe the missing trailing semicolon
has something to do with it? In any case, there's no need to approve
of dead code, nor of code whose formatting isn't even self-consistent
let alone consistent with what's around it.
WalSndKill was doing things exactly backwards: it should first clear
MyWalSnd (to stop signal handlers from touching MyWalSnd->latch),
then disown the latch, and only then mark the WalSnd struct unused by
clearing its pid field.
Also, WalRcvSigUsr1Handler and worker_spi_sighup failed to preserve
errno, which is surely a requirement for any signal handler.
Per discussion of recent buildfarm failures. Back-patch as far
as the relevant code exists.
Replication slots are a crash-safe data structure which can be created
on either a master or a standby to prevent premature removal of
write-ahead log segments needed by a standby, as well as (with
hot_standby_feedback=on) pruning of tuples whose removal would cause
replication conflicts. Slots have some advantages over existing
techniques, as explained in the documentation.
In a few places, we refer to the type of replication slots introduced
by this patch as "physical" slots, because forthcoming patches for
logical decoding will also have slots, but with somewhat different
properties.
Andres Freund and Robert Haas
Commit 6f60fdd701 accidentally removed a
call to XLogWalRcvSendHSFeedback() after flushing received WAL to disk.
The consequence is that when walsender is busy streaming WAL, it doesn't
send HS feedback messages. One is sent if nothing is received from the
master for 100ms, but if there's a steady stream of WAL, it never happens.
Backpatch to 9.3.
Andres Freund and Amit Kapila
If a tablespace was crated inside PGDATA it was backed up both as part
of the PGDATA backup and as the backup of the tablespace. Avoid this
by skipping any directory inside PGDATA that contains one of the active
tablespaces.
Dimitri Fontaine and Magnus Hagander
The backup will not work (without a logarchive, and that's the whole
point of -x) in this case, this patch just changes it to throw an
error instead of crashing when this happens.
Noticed and diagnosed by TAKATSUKA Haruka
In replication, when we shutdown the master, walsender tries to send
all the outstanding WAL records to the standby, and then to exit. This
basically means that all the WAL records are fully synced between
two servers after the clean shutdown of the master. So, after
promoting the standby to new master, we can restart the stopped
master as new standby without the need for a fresh backup from
new master.
But there was one problem so far: though walsender tries to send all
the outstanding WAL records, it doesn't wait for them to be replicated
to the standby. Then, before receiving all the WAL records,
walreceiver can detect the closure of connection and exit. We cannot
guarantee that there is no missing WAL in the standby after clean
shutdown of the master. In this case, backup from new master is
required when restarting the stopped master as new standby.
This patch fixes this problem. It just changes walsender so that it
waits for all the outstanding WAL records to be replicated to the
standby before closing the replication connection.
Per discussion, this is a fix that needs to get backpatched rather than
new feature. So, back-patch to 9.1 where enough infrastructure for
this exists.
Patch by me, reviewed by Andres Freund.
If a standby server has a cascading standby server connected to it, it's
possible that WAL has already been sent up to the next WAL page boundary,
splitting a WAL record in the middle, when the first standby server is
promoted. Don't throw an assertion failure or error in walsender if that
happens.
Also, fix a variant of the same bug in pg_receivexlog: if it had already
received WAL on previous timeline up to a segment boundary, when the
upstream standby server is promoted so that the timeline switch record falls
on the previous segment, pg_receivexlog would miss the segment containing
the timeline switch. To fix that, have walsender send the position of the
timeline switch at end-of-streaming, in addition to the next timeline's ID.
It was previously assumed that the switch happened exactly where the
streaming stopped.
Note: this is an incompatible change in the streaming protocol. You might
get an error if you try to stream over timeline switches, if the client is
running 9.3beta1 and the server is more recent. It should be fine after a
reconnect, however.
Reported by Fujii Masao.
If you have clusters of different versions pointing to the same tablespace
location, we would incorrectly include all the data belonging to the other
versions, too.
Fixes bug #7986, reported by Sergey Burladyan.
We had two copies of this function in the backend and libpq, which was
already pretty bogus, but it turns out that we need it in some other
programs that don't use libpq (such as pg_test_fsync). So put it where
it probably should have been all along. The signal-mask-initialization
support in src/backend/libpq/pqsignal.c stays where it is, though, since
we only need that in the backend.
In copy-out mode, the frontend should not send any messages until the
backend has finished streaming, by sending a CopyDone message. I'm not sure
if it would be legal for the client to send a new query before receiving the
CopyDone message from the backend, but trying to support that would require
bigger changes to the backend code structure.
Fixes an assertion failure reported by Fujii Masao.
This is a forward-patch of commit 6f4b8a4f4f,
applied to 9.2 back in August. The plan was to do something else in master,
but it looks like it's not going to happen, so let's just apply the 9.2
solution to master as well.
Fujii Masao
When a standby server follows the master using WAL archive, and it chooses
a new timeline (recovery_target_timeline='latest'), it only fetches the
timeline history file for the chosen target timeline, not any other history
files that might be missing from pg_xlog. For example, if the current
timeline is 2, and we choose 4 as the new recovery target timeline, the
history file for timeline 3 is not fetched, even if it's part of this
server's history. That's enough for the standby itself - the history file
for timeline 4 includes timeline 3 as well - but if a cascading standby
server wants to recover to timeline 3, it needs the history file. To fix,
when a new recovery target timeline is chosen, try to copy any missing
history files from the archive to pg_xlog between the old and new target
timeline.
A second similar issue was with the WAL files. When a standby recovers from
archive, and it reaches a segment that contains a switch to a new timeline,
recovery fetches only the WAL file labelled with the new timeline's ID. The
file from the new timeline contains a copy of the WAL from the old timeline
up to the point where the switch happened, and recovery recovers it from the
new file. But in streaming replication, walsender only tries to read it
from the old timeline's file. To fix, change walsender to read it from the
new file, so that it behaves the same as recovery in that sense, and doesn't
try to open the possibly nonexistent file with the old timeline's ID.
of timeline, take advantage of that in walreceiver.
Startup process is still in control of choosign the target timeline, by
scanning the timeline history files present in pg_xlog, but walreceiver now
uses the next timeline's ID to fetch its history file immediately after it
has finished streaming the old timeline. Before, the standby would first try
to restart streaming on the old timeline, which fetches the missing timeline
history file as a side-effect, and only then restart from the new timeline.
This patch eliminates the extra iteration, which speeds up the timeline
switch and reduces the noise in the log caused by the extra restart on the
old timeline.
The patch to allow pg_receivexlog to switch timeline added a result set
after copy has ended in START_STREAMING command, to return the next
timeline's ID to the client. But walreceived didn't get the memo, and threw
an error on the unexpected result set. Fix.
