Upstream SELinux has recently marked security_context_t as officially
deprecated, causing warnings with -Wdeprecated-declarations. This is
considered as legacy code for some time now by upstream as
security_context_t got removed from most of the code tree during the
development of 2.3 back in 2014.
This removes all the references to security_context_t in sepgsql/ to be
consistent with SELinux, fixing the warnings. Note that this does not
impact the minimum version of libselinux supported.
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/20200813012735.GC11663@paquier.xyz
Make these examples self-contained by providing declarations of the
user-defined row types they rely on. There wasn't room to do this
in the old doc format, but now there is, and I think it makes the
examples a good bit less confusing.
Now that xmin isn't needed for GetSnapshotData() anymore, it leads to
unnecessary cacheline ping-pong to have it in PGXACT, as it is updated
considerably more frequently than the other PGXACT members.
After the changes in dc7420c2c9, this is a very straight-forward change.
For highly concurrent, snapshot acquisition heavy, workloads this change alone
can significantly increase scalability. E.g. plain pgbench on a smaller 2
socket machine gains 1.07x for read-only pgbench, 1.22x for read-only pgbench
when submitting queries in batches of 100, and 2.85x for batches of 100
'SELECT';. The latter numbers are obviously not to be expected in the
real-world, but micro-benchmark the snapshot computation
scalability (previously spending ~80% of the time in GetSnapshotData()).
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Reviewed-By: Thomas Munro <thomas.munro@gmail.com>
Reviewed-By: David Rowley <dgrowleyml@gmail.com>
Discussion: https://postgr.es/m/20200301083601.ews6hz5dduc3w2se@alap3.anarazel.de
When a table is scanned by heapam_index_build_range_scan (née
IndexBuildHeapScan) and the table lock being held allows concurrent data
changes, it is possible for new HOT chains to sprout in a page that were
unknown when the scan of a page happened. This leads to an error such
as
ERROR: failed to find parent tuple for heap-only tuple at (X,Y) in table "tbl"
because the root tuple was not present when we first obtained the list
of the page's root tuples. This can be fixed by re-obtaining the list
of root tuples, if we see that a heap-only tuple appears to point to a
non-existing root.
This was reported by Anastasia as occurring for BRIN summarization
(which exists since 9.5), but I think it could theoretically also happen
with CREATE INDEX CONCURRENTLY (much older) or REINDEX CONCURRENTLY
(very recent). It seems a happy coincidence that BRIN forces us to
backpatch this all the way to 9.5.
Reported-by: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>
Diagnosed-by: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>
Co-authored-by: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>
Co-authored-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/602d8487-f0b2-5486-0088-0f372b2549fa@postgrespro.ru
Backpatch: 9.5 - master
To make GetSnapshotData() more scalable, it cannot not look at at each proc's
xmin: While snapshot contents do not need to change whenever a read-only
transaction commits or a snapshot is released, a proc's xmin is modified in
those cases. The frequency of xmin modifications leads to, particularly on
higher core count systems, many cache misses inside GetSnapshotData(), despite
the data underlying a snapshot not changing. That is the most
significant source of GetSnapshotData() scaling poorly on larger systems.
Without accessing xmins, GetSnapshotData() cannot calculate accurate horizons /
thresholds as it has so far. But we don't really have to: The horizons don't
actually change that much between GetSnapshotData() calls. Nor are the horizons
actually used every time a snapshot is built.
The trick this commit introduces is to delay computation of accurate horizons
until there use and using horizon boundaries to determine whether accurate
horizons need to be computed.
The use of RecentGlobal[Data]Xmin to decide whether a row version could be
removed has been replaces with new GlobalVisTest* functions. These use two
thresholds to determine whether a row can be pruned:
1) definitely_needed, indicating that rows deleted by XIDs >= definitely_needed
are definitely still visible.
2) maybe_needed, indicating that rows deleted by XIDs < maybe_needed can
definitely be removed
GetSnapshotData() updates definitely_needed to be the xmin of the computed
snapshot.
When testing whether a row can be removed (with GlobalVisTestIsRemovableXid())
and the tested XID falls in between the two (i.e. XID >= maybe_needed && XID <
definitely_needed) the boundaries can be recomputed to be more accurate. As it
is not cheap to compute accurate boundaries, we limit the number of times that
happens in short succession. As the boundaries used by
GlobalVisTestIsRemovableXid() are never reset (with maybe_needed updated by
GetSnapshotData()), it is likely that further test can benefit from an earlier
computation of accurate horizons.
To avoid regressing performance when old_snapshot_threshold is set (as that
requires an accurate horizon to be computed), heap_page_prune_opt() doesn't
unconditionally call TransactionIdLimitedForOldSnapshots() anymore. Both the
computation of the limited horizon, and the triggering of errors (with
SetOldSnapshotThresholdTimestamp()) is now only done when necessary to remove
tuples.
This commit just removes the accesses to PGXACT->xmin from
GetSnapshotData(), but other members of PGXACT residing in the same
cache line are accessed. Therefore this in itself does not result in a
significant improvement. Subsequent commits will take advantage of the
fact that GetSnapshotData() now does not need to access xmins anymore.
Note: This contains a workaround in heap_page_prune_opt() to keep the
snapshot_too_old tests working. While that workaround is ugly, the tests
currently are not meaningful, and it seems best to address them separately.
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Reviewed-By: Thomas Munro <thomas.munro@gmail.com>
Reviewed-By: David Rowley <dgrowleyml@gmail.com>
Discussion: https://postgr.es/m/20200301083601.ews6hz5dduc3w2se@alap3.anarazel.de
If a page range is desummarized at just the right time concurrently with
an index walk, BRIN would raise an error indicating index corruption.
This is scary and unhelpful; silently returning that the page range is
not summarized is sufficient reaction.
This bug was introduced by commit 975ad4e602 as additional protection
against a bug whose actual fix was elsewhere. Backpatch equally.
Reported-By: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>
Diagnosed-By: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/2588667e-d07d-7e10-74e2-7e1e46194491@postgrespro.ru
Backpatch: 9.5 - master
This had gotten a little disjointed over time, and some of the grammar
was sloppy. Rewrite for more clarity.
In passing, re-pgindent some recently added comments.
No code changes.
The reason for doing so is that a subsequent commit will need that to
avoid wraparound issues. As the subsequent change is large this was
split out for easier review.
The reason this is not a perfect straight-forward change is that we do
not want track 64bit xids in the procarray or the WAL. Therefore we
need to advance lastestCompletedXid in relation to 32 bit xids. The
code for that is now centralized in MaintainLatestCompletedXid*.
Author: Andres Freund
Reviewed-By: Thomas Munro, Robert Haas, David Rowley
Discussion: https://postgr.es/m/20200301083601.ews6hz5dduc3w2se@alap3.anarazel.de
Including Full in variable names duplicates the type information and
leads to overly long names. As FullTransactionId cannot accidentally
be casted to TransactionId that does not seem necessary.
Author: Andres Freund
Discussion: https://postgr.es/m/20200724011143.jccsyvsvymuiqfxu@alap3.anarazel.de
This allows the tab completion of REINDEX to handle an optional
parenthesized list of options. This case is more complicated than
VACUUM or ANALYZE because of CONCURRENTLY and the different object types
to consider with the reindex.
Author: Justin Pryzby
Reviewed-by: Alexey Kondratov, Michael Paquier
Discussion: https://postgr.es/m/20200403182712.GR14618@telsasoft.com
They are equivalent, except that StrNCpy() zero-fills the entire
destination buffer instead of providing just one trailing zero. For
all but a tiny number of callers, that's just overhead rather than
being desirable.
Remove StrNCpy() as it is now unused.
In some cases, namestrcpy() is the more appropriate function to use.
While we're here, simplify the API of namestrcpy(): Remove the return
value, don't check for NULL input. Nothing was using that anyway.
Also, remove a few unused name-related functions.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/44f5e198-36f6-6cdb-7fa9-60e34784daae%402ndquadrant.com
This is like CVE-2018-1058 commit
582edc369c. Today, a malicious user of a
publisher or subscriber database can invoke arbitrary SQL functions
under an identity running replication, often a superuser. This fix may
cause "does not exist" or "no schema has been selected to create in"
errors in a replication process. After upgrading, consider watching
server logs for these errors. Objects accruing schema qualification in
the wake of the earlier commit are unlikely to need further correction.
Back-patch to v10, which introduced logical replication.
Security: CVE-2020-14349
Any libpq client can use the header. Clients include backend components
postgres_fdw, dblink, and logical replication apply worker. Back-patch
to v10, because another fix needs this. In released branches, just copy
the header and keep the original.
Hostile objects located within the installation-time search_path could
capture references in an extension's installation or upgrade script.
If the extension is being installed with superuser privileges, this
opens the door to privilege escalation. While such hazards have existed
all along, their urgency increases with the v13 "trusted extensions"
feature, because that lets a non-superuser control the installation path
for a superuser-privileged script. Therefore, make a number of changes
to make such situations more secure:
* Tweak the construction of the installation-time search_path to ensure
that references to objects in pg_catalog can't be subverted; and
explicitly add pg_temp to the end of the path to prevent attacks using
temporary objects.
* Disable check_function_bodies within installation/upgrade scripts,
so that any security gaps in SQL-language or PL-language function bodies
cannot create a risk of unwanted installation-time code execution.
* Adjust lookup of type input/receive functions and join estimator
functions to complain if there are multiple candidate functions. This
prevents capture of references to functions whose signature is not the
first one checked; and it's arguably more user-friendly anyway.
* Modify various contrib upgrade scripts to ensure that catalog
modification queries are executed with secure search paths. (These
are in-place modifications with no extension version changes, since
it is the update process itself that is at issue, not the end result.)
Extensions that depend on other extensions cannot be made fully secure
by these methods alone; therefore, revert the "trusted" marking that
commit eb67623c9 applied to earthdistance and hstore_plperl, pending
some better solution to that set of issues.
Also add documentation around these issues, to help extension authors
write secure installation scripts.
Patch by me, following an observation by Andres Freund; thanks
to Noah Misch for review.
Security: CVE-2020-14350
Coverity pointed out, not unreasonably, that we checked fseeko's
result at every other call site but these. Failure to seek in the
temp file (note this is NOT pg_dump's output file) seems quite
unlikely, and even if it did happen the file length cross-check
further down would probably detect the problem. Still, that's a
poor excuse for not checking the result of a system call.
Testing that an unsigned variable is >= 0 is pretty pointless,
as noted by Coverity and numerous buildfarm members.
In passing, add comment about new uses of "volatile" --- Coverity
doesn't much like that either, but it seems probably necessary.
Since commit efc77cf5f, an indexed query using <@ has required a
full-index scan, so that it actually performs worse than a plain seqscan
would do. As I noted at the time, we'd be better off to not treat <@ as
being indexable by such indexes at all; and that's what this patch does.
It would have been difficult to remove these opclass members without
dropping the whole opclass before commit 9f9682783 fixed GiST opclass
member dependency rules, but now it's quite simple, so let's do it.
I left the existing support code in place for the time being, with
comments noting it's now unreachable. At some point, perhaps we should
remove that code in favor of throwing an error telling people to upgrade
the extension version.
Discussion: https://postgr.es/m/2176979.1596389859@sss.pgh.pa.us
Discussion: https://postgr.es/m/458.1565114141@sss.pgh.pa.us
Teach contrib/amcheck's bt_index_check() function to check agreement
between siblings links. The left sibling's right link should point to a
right sibling page whose left link points back to the same original left
sibling. This extends a check that bt_index_parent_check() always
performed to bt_index_check().
This is the first time amcheck has been taught to perform buffer lock
coupling, which we have explicitly avoided up until now. The sibling
link check tends to catch a lot of real world index corruption with
little overhead, so it seems worth accepting the complexity. Note that
the new lock coupling logic would not work correctly on replica servers
without the changes made by commits 0a7d771f and 9a9db08a (there could
be false positives without those changes).
Author: Andrey Borodin, Peter Geoghegan
Discussion: https://postgr.es/m/0EB0CFA8-CBD8-4296-8049-A2C0F28FAE8C@yandex-team.ru
Ashutosh Bapat noticed that when logical walsender needs to wait for
WAL, and it realizes that it must send a keepalive message to
walreceiver to update the sent-LSN, which *does not* request a reply
from walreceiver, it wrongly sets the flag that it's going to wait for
that reply. That means that any future would-be sender of feedback
messages ends up not sending a feedback message, because they all
believe that a reply is expected.
With built-in logical replication there's not much harm in this, because
WalReceiverMain will send a ping-back every wal_receiver_timeout/2
anyway; but with other logical replication systems (e.g. pglogical) it
can cause significant pain.
This problem was introduced in commit 41d5f8ad73, where the
request-reply flag was changed from true to false to WalSndKeepalive,
without at the same time removing the line that sets
waiting_for_ping_response.
Just removing that line would be a sufficient fix, but it seems better
to shift the responsibility of setting the flag to WalSndKeepalive
itself instead of requiring caller to do it; this is clearly less
error-prone.
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reported-by: Ashutosh Bapat <ashutosh.bapat@2ndquadrant.com>
Backpatch: 9.5 and up
Discussion: https://postgr.es/m/20200806225558.GA22401@alvherre.pgsql
Commit 7259736a6e added the capability to stream changes in ReorderBuffer
which has some tests to test the streaming mode. It is quite possible that
while this test is running a parallel transaction could be logged by
autovacuum. Such a transaction won't perform any insert/update/delete to
non-catalog tables so will be shown as an empty transaction. Fix it by
skipping the empty transactions during this test.
Per report by buildfarm.
Instead of serializing the transaction to disk after reaching the
logical_decoding_work_mem limit in memory, we consume the changes we have
in memory and invoke stream API methods added by commit 45fdc9738b.
However, sometimes if we have incomplete toast or speculative insert we
spill to the disk because we can't generate the complete tuple and stream.
And, as soon as we get the complete tuple we stream the transaction
including the serialized changes.
We can do this incremental processing thanks to having assignments
(associating subxact with toplevel xacts) in WAL right away, and
thanks to logging the invalidation messages at each command end. These
features are added by commits 0bead9af48 and c55040ccd0 respectively.
Now that we can stream in-progress transactions, the concurrent aborts
may cause failures when the output plugin consults catalogs (both system
and user-defined).
We handle such failures by returning ERRCODE_TRANSACTION_ROLLBACK
sqlerrcode from system table scan APIs to the backend or WALSender
decoding a specific uncommitted transaction. The decoding logic on the
receipt of such a sqlerrcode aborts the decoding of the current
transaction and continue with the decoding of other transactions.
We have ReorderBufferTXN pointer in each ReorderBufferChange by which we
know which xact it belongs to. The output plugin can use this to decide
which changes to discard in case of stream_abort_cb (e.g. when a subxact
gets discarded).
We also provide a new option via SQL APIs to fetch the changes being
streamed.
Author: Dilip Kumar, Tomas Vondra, Amit Kapila, Nikhil Sontakke
Reviewed-by: Amit Kapila, Kuntal Ghosh, Ajin Cherian
Tested-by: Neha Sharma, Mahendra Singh Thalor and Ajin Cherian
Discussion: https://postgr.es/m/688b0b7f-2f6c-d827-c27b-216a8e3ea700@2ndquadrant.com
Make the nbtree page split REDO routine consistent with original
execution in its approach to acquiring and releasing buffer locks (at
least for pages on the tree level of the page being split). This brings
btree_xlog_split() in line with btree_xlog_unlink_page(), which was
taught to couple buffer locks by commit 9a9db08a.
Note that the precise order in which we both acquire and release sibling
buffer locks in btree_xlog_split() now matches original execution
exactly (the precise order in which the locks are released probably
doesn't matter much, but we might as well be consistent about it).
The rule for nbtree REDO routines from here on is that same-level locks
should be acquired in an order that's consistent with original
execution. It's not practical to have a similar rule for cross-level
page locks, since for the most part original execution holds those locks
for a period that spans multiple atomic actions/WAL records. It's also
not necessary, because clearly the cross-level lock coupling is only
truly needed during original execution because of the presence of
concurrent inserters.
This is not a bug fix (unlike the similar aforementioned commit, commit
9a9db08a). The immediate reason to tighten things up in this area is to
enable an upcoming enhancement to contrib/amcheck that allows it to
verify that sibling links are in agreement with only an AccessShareLock
(this check produced false positives when run on a replica server on
account of the inconsistency fixed by this commit). But that's not the
only reason to be stricter here.
It is generally useful to make locking on replicas be as close to what
happens during original execution as practically possible. It makes it
less likely that hard to catch bugs will slip in in the future. The
previous state of affairs seems to be a holdover from before the
introduction of Hot Standby, when buffer lock acquisitions during
recovery were totally unnecessary. See also: commit 3bbf668d, which
tightened things up in this area a few years after the introduction of
Hot Standby.
Discussion: https://postgr.es/m/CAH2-Wz=465cJj11YXD9RKH8z=nhQa2dofOZ_23h67EXUGOJ00Q@mail.gmail.com
We have various cases where we allow DDL on tables to be performed with
less than full AccessExclusiveLock. This requires concurrent queries
to be able to cope with the DDL change mid-flight, but up to now we had
no repeatable way to test such cases. To improve that, invent a test
module that allows halting a backend after planning and then resuming
execution once we've done desired actions in another session. (The same
approach could be used to inject delays in other places, if there's a
suitable hook available.)
This commit includes a single test case, which is meant to exercise the
previously-untestable ExecCreatePartitionPruneState code repaired by
commit 7a980dfc6. We'd probably not bother with this if that were the
only foreseen benefit, but I expect additional test cases will use this
infrastructure in the future.
Test module by Andy Fan, partition-addition test case by me.
Discussion: https://postgr.es/m/20200802181131.GA27754@telsasoft.com
Make the nbtree page split REDO routine variable names consistent with
_bt_split() (which handles the original execution of page splits).
These names make the code easier to follow by making the distinction
between the original page and the left half of the split clear. (The
left half of the split page is a temp page that REDO creates to replace
the origpage contents.)
Also reduce the elevel used when adding a new high key to the temp page
from PANIC to ERROR to be consistent. We already only raise an ERROR
when data item PageAddItem() temp page calls fail.
Commit 13838740f fixed some issues with step generation in partition
pruning, but there was yet another one: get_steps_using_prefix() assumes
that clauses in the passed-in prefix list are sorted in ascending order
of their partition key numbers, but the caller failed to ensure this for
range partitioning, which led to an assertion failure in debug builds.
Adjust the caller function to arrange the clauses in the prefix list in
the required order for range partitioning.
Back-patch to v11, like the previous commit.
Patch by me, reviewed by Amit Langote.
Discussion: https://postgr.es/m/CAPmGK16jkXiFG0YqMbU66wte-oJTfW6D1HaNvQf%3D%2B5o9%3Dm55wQ%40mail.gmail.com
This will be helpful if it ever proves necessary to revoke an opclass's
support for deduplication.
Backpatch: 13-, where nbtree deduplication was introduced.
9bdb300de modified the EXPLAIN output for Hash Aggregate to show details
from parallel workers. However, it neglected to consider that a given
parallel worker may not have assisted with the given Hash Aggregate. This
can occur when workers fail to start or during Parallel Append with
enable_partitionwise_join enabled when only a single worker is working on
a non-parallel aware sub-plan. It could also happen if a worker simply
wasn't fast enough to get any work done before other processes went and
finished all the work.
The bogus output came from the fact that ExplainOpenWorker() skipped
showing any details for non-initialized workers but show_hashagg_info()
did show details from the worker. This meant that the worker properties
that were shown were not properly attributed to the worker that they
belong to.
In passing, we also now don't show Hash Aggregate properties for the
leader process when it did not contribute any work to the Hash Aggregate.
This can occur either during Parallel Append when only a parallel worker
worked on a given sub plan or with parallel_leader_participation set to
off. This aims to make the behavior of Hash Aggregate's EXPLAIN output
more similar to Sort's.
Reported-by: Justin Pryzby
Discussion: https://postgr.es/m/20200805012105.GZ28072%40telsasoft.com
Backpatch-through: 13, where the original breakage was introduced
This seems more correct, because other before_shmem_exit calls may
expect the infrastructure that is needed to run queries and access the
database to be working, and also because this cleanup has nothing to
do with shared memory.
There are no known user-visible consequences to this, though, apart
from what was previous fixed by commit
303640199d and back-patched as commit
bcbc27251d and commit
f7013683d9, so for now, no back-patch.
Bharath Rupireddy
Discussion: http://postgr.es/m/CALj2ACWk7j4F2v2fxxYfrroOF=AdFNPr1WsV+AGtHAFQOqm_pw@mail.gmail.com
Since we no longer require AccessExclusiveLock to add a partition,
the executor may see that a partitioned table has more partitions
than the planner saw. ExecCreatePartitionPruneState's code for
matching up the partition lists in such cases was faulty, and would
misbehave if the planner had successfully pruned any partitions from
the query. (Thus, trouble would occur only if a partition addition
happens concurrently with a query that uses both static and dynamic
partition pruning.) This led to an Assert failure in debug builds,
and probably to crashes or query misbehavior in production builds.
To repair the bug, just explicitly skip zeroes in the plan's
relid_map[] list. I also made some cosmetic changes to make the code
more readable (IMO anyway). Also, convert the cross-checking Assert
to a regular test-and-elog, since it's now apparent that this logic
is more fragile than one would like.
Currently, there's no way to repeatably exercise this code, except
with manual use of a debugger to stop the backend between planning
and execution. Hence, no test case in this patch. We oughta do
something about that testability gap, but that's for another day.
Amit Langote and Tom Lane, per report from Justin Pryzby. Oversight
in commit 898e5e329; backpatch to v12 where that appeared.
Discussion: https://postgr.es/m/20200802181131.GA27754@telsasoft.com
Currently, page unlink leaves remaining items "as is", but replay of
corresponding WAL-record re-initializes page leaving it with no items.
For the sake of consistency, this commit makes primary delete all the items
during page unlink as well.
Thanks to this change, we now don't mask contents of deleted btree page for
WAL consistency checking.
Discussion: https://postgr.es/m/CAPpHfdt_OTyQpXaPJcWzV2N-LNeNJseNB-K_A66qG%3DL518VTFw%40mail.gmail.com
Author: Alexander Korotkov
Reviewed-by: Peter Geoghegan
A couple of test cases had connect_timeout=14, a value that seems
to have been plucked from a hat. While it's more than sufficient
for normal cases, slow/overloaded buildfarm machines can get a timeout
failure here, as per recent report from "sungazer". Increase to 180
seconds, which is in line with our typical timeouts elsewhere in
the regression tests.
Back-patch to 9.6; the code looks different in 9.5, and this doesn't
seem to be quite worth the effort to adapt to that.
Report: https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=sungazer&dt=2020-08-04%2007%3A12%3A22
It was possible for the logic used by backward scans (which must reason
about concurrent page splits/deletions in its own peculiar way) to
become confused when running on a replica. Concurrent replay of a WAL
record that describes the second phase of page deletion could cause
_bt_walk_left() to get confused. btree_xlog_unlink_page() simply failed
to adhere to the same locking protocol that we use on the primary, which
is obviously wrong once you consider these two disparate functions
together. This bug is present in all stable branches.
More concretely, the problem was that nothing stopped _bt_walk_left()
from observing inconsistencies between the deletion's target page and
its original sibling pages when running on a replica. This is true even
though the second phase of page deletion is supposed to work as a single
atomic action. Queries running on replicas raised "could not find left
sibling of block %u in index %s" can't-happen errors when they went back
to their scan's "original" page and observed that the page has not been
marked deleted (even though it really was concurrently deleted).
There is no evidence that this actually happened in the real world. The
issue came to light during unrelated feature development work. Note
that _bt_walk_left() is the only code that cares about the difference
between a half-dead page and a fully deleted page that isn't also
exclusively used by nbtree VACUUM (unless you include contrib/amcheck
code). It seems very likely that backward scans are the only thing that
could become confused by the inconsistency. Even amcheck's complex
bt_right_page_check_scankey() dance was unaffected.
To fix, teach btree_xlog_unlink_page() to lock the left sibling, target,
and right sibling pages in that order before releasing any locks (just
like _bt_unlink_halfdead_page()). This is the simplest possible
approach. There doesn't seem to be any opportunity to be more clever
about lock acquisition in the REDO routine, and it hardly seems worth
the trouble in any case.
This fix might enable contrib/amcheck verification of leaf page sibling
links with only an AccessShareLock on the relation. An amcheck patch
from Andrey Borodin was rejected back in January because it clashed with
btree_xlog_unlink_page()'s lax approach to locking pages. It now seems
likely that the real problem was with btree_xlog_unlink_page(), not the
patch.
This is a low severity, low likelihood bug, so no backpatch.
Author: Michail Nikolaev
Diagnosed-By: Michail Nikolaev
Discussion: https://postgr.es/m/CANtu0ohkR-evAWbpzJu54V8eCOtqjJyYp3PQ_SGoBTRGXWhWRw@mail.gmail.com
Add a documenting assertion that's similar to the nearby assertion added
by commit cd8c73a3. This conveys that the entire call to _bt_pagedel()
does no work if it isn't possible to get a descent stack for the initial
scanblkno page.
A moment's examination of these queries is sufficient to see that
they do not produce duplicate rows, unless perhaps there's
catalog corruption. Using DISTINCT anyway is inefficient and
confusing; moreover it sets a poor example for anyone who
refers to psql -E output to see how to query the catalogs.
This ought to work much like C's "#elif defined(name)"; but the code
implemented it in a way equivalent to endif followed by ifdef, so that
it didn't matter whether any previous branch of the IF construct had
succeeded. Fix that; add some test cases covering elif and nested IFs;
and improve the documentation, which also seemed a bit confused.
AFAICS the code has been like this since the feature was added in 1999
(commit b57b0e044). So while it's surely wrong, there might be code
out there relying on the current behavior. Hence, don't back-patch
into stable branches. It seems all right to fix it in v13 though.
Per report from Ashutosh Sharma. Reviewed by Ashutosh Sharma and
Michael Meskes.
Discussion: https://postgr.es/m/CAE9k0P=dQk9X0cU2tN49S7a9tv733-e1pVdpB1P-pWJ5PdTktg@mail.gmail.com
This is useful for monitoring purposes with log parsing. Similarly to
pg_stat_activity, the leader's PID is shown only for active parallel
workers, minimizing the log footprint for the leaders as the equivalent
shared memory field is set as long as a backend is alive.
Author: Justin Pryzby
Reviewed-by: Álvaro Herrera, Michael Paquier, Julien Rouhaud, Tom Lane
Discussion: https://postgr.es/m/20200315111831.GA21492@telsasoft.com
Instead of writing a query to psql's stdin, use -c. This avoids a
failure where psql exits before we write, seen a few times on the build
farm. Thanks to Tom Lane for the suggestion.
Back-patch to 11, where the LDAP tests arrived.
Reviewed-by: Noah Misch <noah@leadboat.com>
Discussion: https://postgr.es/m/CA%2BhUKGLFmW%2BHQYPeKiwSp5sdFFHtFViCpw4Mh6yAgEx74r5-Cw%40mail.gmail.com
The type-name pattern in \dAc and \dAf was matched only to the actual
pg_type.typname string, which is fairly user-unfriendly in cases where
that is not what's shown to the user by format_type (compare "_int4"
and "integer[]"). Make this code match what \dT does, i.e. match the
pattern against either typname or format_type() output. Also fix its
broken handling of schema-name restrictions. (IOW, make these
processSQLNamePattern calls match \dT's.) While here, adjust
whitespace to make the query a little prettier in -E output, too.
Also improve some inaccuracies and shaky grammar in the related
documentation.
Noted while working on a patch for intarray's opclasses; I wondered
why I couldn't get a match to "integer*" for the input type name.
Heikki Linnakangas