Non-zero vacuum_defer_cleanup_age values cause pg_upgrade freezing of
the system catalogs to be incomplete, or do nothing. This will cause
the upgrade to fail in confusing ways.
Reported-by: Laurenz Albe
Discussion: https://postgr.es/m/7d6f6c22ba05ce0c526e9e8b7bfa8105e7da45e6.camel@cybertec.at
Backpatch-through: 9.5
Our documentation failed to point out that REPEATABLE READ is really
snapshot isolation, which might be important to some users. Point to
the standard reference paper for this complicated topic.
Likewise, add a reference to the VLDB paper about PostgreSQL SSI, for
technical information about our SSI implementation and how it compares
to S2PL.
While here, add a note about catalog access using a lower isolation
level, per recent user complaint.
Back-patch to all releases.
Reported-by: Kyle Kingsbury <aphyr@jepsen.io>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Peter Geoghegan <pg@bowt.ie>
Reviewed-by: Tatsuo Ishii <ishii@sraoss.co.jp>
Discussion: https://postgr.es/m/db7b729d-0226-d162-a126-8a8ab2dc4443%40jepsen.io
Discussion: https://postgr.es/m/16454-9408996bb1750faf%40postgresql.org
When there is just one non-null input value, and it is infinity or NaN,
aggregates such as stddev_pop and covar_pop should produce a NaN
result, because the calculation is not well-defined. They used to do
so, but since we adopted Youngs-Cramer aggregation in commit e954a727f,
they produced zero instead. That's an oversight, so fix it. Add tests
exercising these edge cases.
Affected aggregates are
var_pop(double precision)
stddev_pop(double precision)
var_pop(real)
stddev_pop(real)
regr_sxx(double precision,double precision)
regr_syy(double precision,double precision)
regr_sxy(double precision,double precision)
regr_r2(double precision,double precision)
regr_slope(double precision,double precision)
regr_intercept(double precision,double precision)
covar_pop(double precision,double precision)
corr(double precision,double precision)
Back-patch to v12 where the behavior change was accidentally introduced.
Report and patch by me; thanks to Dean Rasheed for review.
Discussion: https://postgr.es/m/353062.1591898766@sss.pgh.pa.us
When merging two NumericAggStates, the code missed adding the new
state's NaNcount unless its N was also nonzero; since those counts
are independent, this is wrong.
This would only have visible effect if some partial aggregate scans
found only NaNs while earlier ones found only non-NaNs; then we could
end up falsely deciding that there were no NaNs and fail to return a
NaN final result as expected. That's pretty improbable, so it's no
surprise this hasn't been reported from the field. Still, it's a bug.
I didn't try to produce a regression test that would show the bug,
but I did notice that these functions weren't being reached at all
in our regression tests, so I improved the tests to at least
exercise them. With these additions, I see pretty complete code
coverage on the aggregation-related functions in numeric.c.
Back-patch to 9.6 where this code was introduced. (I only added
the improved test case as far back as v10, though, since the
relevant part of aggregates.sql isn't there at all in 9.6.)
SSI's HeapCheckForSerializableConflictOut() test failed to correctly
handle conditions involving a concurrently inserted tuple which is later
concurrently updated by a separate transaction . A SELECT statement
that called HeapCheckForSerializableConflictOut() could end up using the
same XID (updater's XID) for both the original tuple, and the successor
tuple, missing the XID of the xact that created the original tuple
entirely. This only happened when neither tuple from the chain was
visible to the transaction's MVCC snapshot.
The observable symptoms of this bug were subtle. A pair of transactions
could commit, with the later transaction failing to observe the effects
of the earlier transaction (because of the confusion created by the
update to the non-visible row). This bug dates all the way back to
commit dafaa3ef, which added SSI.
To fix, make sure that we check the xmin of concurrently inserted tuples
that happen to also have been updated concurrently.
Author: Peter Geoghegan
Reported-By: Kyle Kingsbury
Reviewed-By: Thomas Munro
Discussion: https://postgr.es/m/db7b729d-0226-d162-a126-8a8ab2dc4443@jepsen.io
Backpatch: All supported versions
The previous description string still described the pre-PostgreSQL
10 (pre eb61136dc7) behavior of
selecting between encrypted and unencrypted, but it is now choosing
between encryption algorithms.
Previously we used pg_atomic_write_64_impl inside
pg_atomic_init_u64. That works correctly, but on platforms without
64bit single copy atomicity it could trigger spurious valgrind errors
about uninitialized memory, because we use compare_and_swap for atomic
writes on such platforms.
I previously suppressed one instance of this problem (6c878edc1d),
but as Tom reports that wasn't enough. As the atomic variable cannot
yet be concurrently accessible during initialization, it seems better
to have pg_atomic_init_64_impl set the value directly.
Change pg_atomic_init_u32_impl for symmetry.
Reported-By: Tom Lane
Author: Andres Freund
Discussion: https://postgr.es/m/1714601.1591503815@sss.pgh.pa.us
Backpatch: 9.5-
Commit 7be5d8df1f surfaced the logic
error, which had no functional implications, by adding "use warnings".
The buildfarm always customizes PROVE_FLAGS, so the warning did not
appear there. Back-patch to 9.5 (all supported versions).
Even when we've concluded that we have a hard write failure on the
socket, we should continue to try to read data. This gives us an
opportunity to collect any final error message that the backend might
have sent before closing the connection; moreover it is the job of
pqReadData not pqSendSome to close the socket once EOF is detected.
Due to an oversight in 1f39a1c06, pqSendSome failed to try to collect
data in the case where we'd already set write_failed. The problem was
masked for ordinary query operations (which really only make one write
attempt anyway), but COPY to the server would continue to send data
indefinitely after a mid-COPY connection loss.
Hence, add pqReadData calls into the paths where pqSendSome drops data
because of write_failed. If we've lost the connection, this will
eventually result in closing the socket and setting CONNECTION_BAD,
which will cause PQputline and siblings to report failure, allowing
the application to terminate the COPY sooner. (Basically this restores
what happened before 1f39a1c06.)
There are related issues that this does not solve; for example, if the
backend sends an error but doesn't drop the connection, we did and
still will keep pumping COPY data as long as the application sends it.
Fixing that will require application-visible behavior changes though,
and anyway it's an ancient behavior that we've had few complaints about.
For now I'm just trying to fix the regression from 1f39a1c06.
Per a complaint from Andres Freund. Back-patch into v12 where
1f39a1c06 came in.
Discussion: https://postgr.es/m/20200603201242.ofvm4jztpqytwfye@alap3.anarazel.de
Commit 5e0928005 changed the planner so that, instead of blindly using
DEFAULT_COLLATION_OID when invoking operators for selectivity estimation,
it would use the collation of the column whose statistics we're
considering. This was recognized as still being not quite the right
thing, but it seemed like a good incremental improvement. However,
shortly thereafter we introduced nondeterministic collations, and that
creates cases where operators can fail if they're passed the wrong
collation. We don't want planning to fail in cases where the query itself
would work, so this means that we *must* use the query's collation when
invoking operators for estimation purposes.
The only real problem this creates is in ineq_histogram_selectivity, where
the binary search might produce a garbage answer if we perform comparisons
using a different collation than the column's histogram is ordered with.
However, when the query's collation is significantly different from the
column's default collation, the estimate we previously generated would be
pretty irrelevant anyway; so it's not clear that this will result in
noticeably worse estimates in practice. (A follow-on patch will improve
this situation in HEAD, but it seems too invasive for back-patch.)
The patch requires changing the signatures of mcv_selectivity and allied
functions, which are exported and very possibly are used by extensions.
In HEAD, I just did that, but an API/ABI break of this sort isn't
acceptable in stable branches. Therefore, in v12 the patch introduces
"mcv_selectivity_ext" and so on, with signatures matching HEAD, and makes
the old functions into wrappers that assume DEFAULT_COLLATION_OID should
be used. That does not match the prior behavior, but it should avoid risk
of failure in most cases. (In practice, I think most extension datatypes
aren't collation-aware, so the change probably doesn't matter to them.)
Per report from James Lucas. Back-patch to v12 where the problem was
introduced.
Discussion: https://postgr.es/m/CAAFmbbOvfi=wMM=3qRsPunBSLb8BFREno2oOzSBS=mzfLPKABw@mail.gmail.com
If the flag value is lost, logical decoding would work the same way as
REPLICA IDENTITY NOTHING, meaning that no old tuple values would be
included in the changes anymore produced by logical decoding.
Author: Michael Paquier
Reviewed-by: Euler Taveira
Discussion: https://postgr.es/m/20200603065340.GK89559@paquier.xyz
Backpatch-through: 12
It's intentional that we don't allow values greater than 24 hours,
while we do allow "24:00:00" as well as "23:59:60" as inputs.
However, the range check was miscoded in such a way that it would
accept "23:59:60.nnn" with a nonzero fraction. For time or timetz,
the stored result would then be greater than "24:00:00" which would
fail dump/reload, not to mention possibly confusing other operations.
Fix by explicitly calculating the result and making sure it does not
exceed 24 hours. (This calculation is redundant with what will happen
later in tm2time or tm2timetz. Maybe someday somebody will find that
annoying enough to justify refactoring to avoid the duplication; but
that seems too invasive for a back-patched bug fix, and the cost is
probably unmeasurable anyway.)
Note that this change also rejects such input as the time portion
of a timestamp(tz) value.
Back-patch to v10. The bug is far older, but to change this pre-v10
we'd need to ensure that the logic behaves sanely with float timestamps,
which is possibly nontrivial due to roundoff considerations.
Doesn't really seem worth troubling with.
Per report from Christoph Berg.
Discussion: https://postgr.es/m/20200520125807.GB296739@msg.df7cb.de
Fix some more violations of the "only straight-line code inside a
spinlock" rule. These are hazardous not only because they risk
holding the lock for an excessively long time, but because it's
possible for palloc to throw elog(ERROR), leaving a stuck spinlock
behind.
copy_replication_slot() had two separate places that did pallocs
while holding a spinlock. We can make the code simpler and safer
by copying the whole ReplicationSlot struct into a local variable
while holding the spinlock, and then referencing that copy.
(While that's arguably more cycles than we really need to spend
holding the lock, the struct isn't all that big, and this way seems
far more maintainable than copying fields piecemeal. Anyway this
is surely much cheaper than a palloc.) That bug goes back to v12.
InvalidateObsoleteReplicationSlots() not only did a palloc while
holding a spinlock, but for extra sloppiness then leaked the memory
--- probably for the lifetime of the checkpointer process, though
I didn't try to verify that. Fortunately that silliness is new
in HEAD.
pg_get_replication_slots() had a cosmetic violation of the rule,
in that it only assumed it's safe to call namecpy() while holding
a spinlock. Still, that's a hazard waiting to bite somebody, and
there were some other cosmetic coding-rule violations in the same
function, so clean it up. I back-patched this as far as v10; the
code exists before that but it looks different, and this didn't
seem important enough to adapt the patch further back.
Discussion: https://postgr.es/m/20200602.161518.1399689010416646074.horikyota.ntt@gmail.com
The group of wal_init_zero and wal_recycle is WAL_SETTINGS in guc.c,
but previously their documents were located in
"Replication"/"Sending Servers" section. This commit moves them to
the proper section "Write Ahead Log"/"Settings".
Back-patch to v12 where wal_init_zero and wal_recycle parameters
were introduced.
Author: Fujii Masao
Discussion: https://postgr.es/m/b5190ab4-a169-6a42-0e49-aed0807c8976@oss.nttdata.com
This issue has been present since the introduction of this code as of
a3519a2 from 2002, and has been found by buildfarm member prion that
uses RELCACHE_FORCE_RELEASE via the tests introduced recently in
e786be5.
Discussion: https://postgr.es/m/20200601022055.GB4121@paquier.xyz
Backpatch-through: 9.5
A relation that has no storage initializes rd_tableam to NULL, which
caused those two functions to crash because of a pointer dereference.
Note that in 11 and older versions, this has always failed with a
confusing error "could not open file".
These two functions are used by the Postgres ODBC driver, which requires
them only when connecting to a backend strictly older than 8.1. When
connected to 8.2 or a newer version, the driver uses a RETURNING clause
instead whose support has been added in 8.2, so it should be possible to
just remove both functions in the future. This is left as an issue to
address later.
While on it, add more regression tests for those functions as we never
really had coverage for them, and for aggregates of TIDs.
Reported-by: Jaime Casanova, via sqlsmith
Author: Michael Paquier
Reviewed-by: Álvaro Herrera
Discussion: https://postgr.es/m/CAJGNTeO93u-5APMga6WH41eTZ3Uee9f3s8dCpA-GSSqNs1b=Ug@mail.gmail.com
Backpatch-through: 12
The documentation of REINDEX includes a complete description of
CONCURRENTLY and its advantages as well as its disadvantages, but
reindexdb was not really clear about all that.
From discussion with Tom Lane, based on a report from Andrey Klychkov.
Discussion: https://postgr.es/m/1590486572.205117372@f500.i.mail.ru
Backpatch-through: 12
The repeat() function loops for potentially a long time without
ever checking for interrupts. This prevents, for example, a query
cancel from interrupting until the work is all done. Fix by
inserting a CHECK_FOR_INTERRUPTS() into the loop.
Backpatch to all supported versions.
Discussion: https://www.postgresql.org/message-id/flat/8692553c-7fe8-17d9-cbc1-7cddb758f4c6%40joeconway.com
ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE was used in an ereport with the
same message but different errdetail a few lines earlier, so use that
here as well.
Backpatch-through: 11
These were missed when these were added to pg_hba.conf in PG 12;
updates docs and pg_hba.conf.sample.
Reported-by: Arthur Nascimento
Bug: 16380
Discussion: https://postgr.es/m/20200421182736.GG19613@momjian.us
Backpatch-through: 12
The target failed, tested $PATH binaries, or tested a stale temporary
installation. Commit c66b438db6 missed
this. Back-patch to 9.5 (all supported versions).
When installing binaries and libraries using the MSVC installation
routines, the operation gets done after moving to the root folder, whose
location is detected by checking if "configure" exists two times in a
row. So, calling the installation script from src/tools/msvc/ with an
extra "configure" file four levels up the root path of the code tree
causes the execution to go further up, leading to a failure in finding
the builds. This commit fixes the issue by moving to the root folder of
the code tree only once, when necessary.
Author: Arnold Müller
Reviewed-by: Daniel Gustafsson
Discussion: https://postgr.es/m/16343-f638f67e7e52b86c@postgresql.org
Backpatch-through: 9.5
The description missed a comma and lacked an explanation of what happens
with REPLICA IDENTITY USING INDEX when the dependent index is dropped.
Author: Marina Polyakova
Reviewed-by: Daniel Gustafsson, Michael Paquier
Discussion: https://postgr.es/m/ad1a0badc32658b1bbb07aa312346a1d@postgrespro.ru
Backpatch-through: 9.5
In a logical replication subscriber, a table using REPLICA IDENTITY FULL
which has a primary key would try to use the primary key's index
available to scan for a tuple, but an assertion only assumed as correct
the case of an index associated to REPLICA IDENTITY USING INDEX. This
commit corrects the assertion so as the use of a primary key index is a
valid case.
Reported-by: Dilip Kumar
Analyzed-by: Dilip Kumar
Author: Euler Taveira
Reviewed-by: Michael Paquier, Masahiko Sawada
Discussion: https://postgr.es/m/CAFiTN-u64S5bUiPL1q5kwpHNd0hRnf1OE-bzxNiOs5zo84i51w@mail.gmail.com
Backpatch-through: 10
The previous coding zeroed out offsetof(ReplicationStateCtl, states)
more bytes than it was entitled to, as a consequence of starting the
zeroing from the wrong pointer (or, if you prefer, using the wrong
calculation of how much to zero).
It's unsurprising that this has not caused any reported problems,
since it can be expected that the newly-allocated block is at the end
of what we've used in shared memory, and we always make the shmem
block substantially bigger than minimally necessary. Nonetheless,
this is wrong and it could bite us someday; plus it's a dangerous
model for somebody to copy.
This dates back to the introduction of this code (commit 5aa235042),
so back-patch to all supported branches.
_bt_killitems marks btree items dead when a scan leaves the page where
they live, but it does so with only share lock (to improve concurrency).
This was historicall okay, since killing a dead item has no
consequences. However, with the advent of data checksums and
wal_log_hints, this action incurs a WAL full-page-image record of the
page. Multiple concurrent processes would write the same page several
times, leading to WAL bloat. The probability of this happening can be
reduced by only killing items if they're not already dead, so change the
code to do that.
The problem could eliminated completely by having _bt_killitems upgrade
to exclusive lock upon seeing a killable item, but that would reduce
concurrency so it's considered a cure worse than the disease.
Backpatch all the way back to 9.5, since wal_log_hints was introduced in
9.4.
Author: Masahiko Sawada <masahiko.sawada@2ndquadrant.com>
Discussion: https://postgr.es/m/CA+fd4k6PeRj2CkzapWNrERkja5G0-6D-YQiKfbukJV+qZGFZ_Q@mail.gmail.com
amcheck expects at least hikey to always exist on leaf page even if it is
deleted page. But replica reinitializes page during replay of page deletion,
causing deleted page to have no items. Thus, replay of page deletion can
cause an error in concurrent amcheck run.
This commit relaxes amcheck expectation making it tolerate deleted page with
no items.
Reported-by: Konstantin Knizhnik
Discussion: https://postgr.es/m/CAPpHfdt_OTyQpXaPJcWzV2N-LNeNJseNB-K_A66qG%3DL518VTFw%40mail.gmail.com
Author: Alexander Korotkov
Reviewed-by: Peter Geoghegan
Backpatch-through: 11
