Previously this code used PageGetHeapFreeSpace on heap pages,
and usually used PageGetFreeSpace on index pages (though for some
reason GetHashPageStats used PageGetExactFreeSpace instead).
The difference is that those functions subtract off the size of
a line pointer, and PageGetHeapFreeSpace has some additional
rules about returning zero if adding another line pointer would
require exceeding MaxHeapTuplesPerPage. Those things make sense
when testing to see if a new tuple can be put on the page, but
they seem pretty strange for pure statistics collection.
Additionally, statapprox_heap had a special rule about counting
a "new" page as being fully available space. This also seems
strange, because it's not actually usable until VACUUM or some
such process initializes the page. Moreover, it's inconsistent
with what pgstat_heap does, which is to count such a page as
having zero free space. So make it work like pgstat_heap, which
as of this patch unconditionally calls PageGetExactFreeSpace.
This is more of a definitional change than a bug fix, so no
back-patch. The module's documentation doesn't define exactly
what "free space" means either, so we left that as-is.
Frédéric Yhuel, reviewed by Rafia Sabih and Andreas Karlsson.
Discussion: https://postgr.es/m/3a18f843-76f6-4a84-8cca-49537fefa15d@dalibo.com
SPI_connect/SPI_connect_ext have not returned any value other than
SPI_OK_CONNECT since commit 1833f1a1c in v10; any errors are thrown
via ereport. (The most likely failure is out-of-memory, which has
always been thrown that way, so callers had better be prepared for
such errors.) This makes it somewhat pointless to check these
functions' result, and some callers within our code haven't been
bothering; indeed, the only usage example within spi.sgml doesn't
bother. So it's likely that the omission has propagated into
extensions too.
Hence, let's standardize on not checking, and document the return
value as historical, while not actually changing these functions'
behavior. (The original proposal was to change their return type
to "void", but that would needlessly break extensions that are
conforming to the old practice.) This saves a small amount of
boilerplate code in a lot of places.
Stepan Neretin
Discussion: https://postgr.es/m/CAMaYL5Z9Uk8cD9qGz9QaZ2UBJFOu7jFx5Mwbznz-1tBbPDQZow@mail.gmail.com
OpenSSL 1.0.2 has been EOL from the upstream OpenSSL project for
some time, and is no longer the default OpenSSL version with any
vendor which package PostgreSQL. By retiring support for OpenSSL
1.0.2 we can remove a lot of no longer required complexity for
managing state within libcrypto which is now handled by OpenSSL.
Reviewed-by: Jacob Champion <jacob.champion@enterprisedb.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/ZG3JNursG69dz1lr@paquier.xyz
Discussion: https://postgr.es/m/CA+hUKGKh7QrYzu=8yWEUJvXtMVm_CNWH1L_TLWCbZMwbi1XP2Q@mail.gmail.com
This test occasionally shows
+WARNING: could not get result of cancel request due to timeout
which appears to be because the cancel request is sometimes unluckily
sent to the remote session between queries, and then it's ignored.
This patch tries to make that less probable in three ways:
1. Use a test query that does not involve remote estimates, so that
no EXPLAINs are sent.
2. Make sure that the remote session is ready-to-go (transaction
started, SET commands sent) before we start the timer.
3. Increase the statement_timeout to 100ms, to give the local
session enough time to plan and issue the query.
We might have to go higher than 100ms to make this adequately
stable in the buildfarm, but let's see how it goes.
Back-patch to v17 where this test was introduced.
Jelte Fennema-Nio and Tom Lane
Discussion: https://postgr.es/m/578934.1725045685@sss.pgh.pa.us
Commit 5bec1d6bc5 changed the memory usage updates of the
ReorderBufferTXN to zero all at once by subtracting txn->size, rather
than updating it for each change. However, if TOAST reconstruction
data remained in the transaction when freeing it, there were cases
where it further subtracted the memory counter from zero, resulting in
an assertion failure.
This change calculates the memory size for each change and updates the
memory usage to precisely the amount that has been freed.
Backpatch to v17, where this was introducd.
Reviewed-by: Amit Kapila, Shlok Kyal
Discussion: https://postgr.es/m/CAD21AoAqkNUvicgKPT_dXzNoOwpPkVTg0QPPxEcWmzT0moCJ1g%40mail.gmail.com
Backpatch-through: 17
Previously, when a path type was disabled by e.g. enable_seqscan=false,
we either avoided generating that path type in the first place, or
more commonly, we added a large constant, called disable_cost, to the
estimated startup cost of that path. This latter approach can distort
planning. For instance, an extremely expensive non-disabled path
could seem to be worse than a disabled path, especially if the full
cost of that path node need not be paid (e.g. due to a Limit).
Or, as in the regression test whose expected output changes with this
commit, the addition of disable_cost can make two paths that would
normally be distinguishible in cost seem to have fuzzily the same cost.
To fix that, we now count the number of disabled path nodes and
consider that a high-order component of both the startup cost and the
total cost. Hence, the path list is now sorted by disabled_nodes and
then by total_cost, instead of just by the latter, and likewise for
the partial path list. It is important that this number is a count
and not simply a Boolean; else, as soon as we're unable to respect
disabled path types in all portions of the path, we stop trying to
avoid them where we can.
Because the path list is now sorted by the number of disabled nodes,
the join prechecks must compute the count of disabled nodes during
the initial cost phase instead of postponing it to final cost time.
Counts of disabled nodes do not cross subquery levels; at present,
there is no reason for them to do so, since the we do not postpone
path selection across subquery boundaries (see make_subplan).
Reviewed by Andres Freund, Heikki Linnakangas, and David Rowley.
Discussion: http://postgr.es/m/CA+TgmoZ_+MS+o6NeGK2xyBv-xM+w1AfFVuHE4f_aq6ekHv7YSQ@mail.gmail.com
e85662df44 implemented GetStrictOldestNonRemovableTransactionId() function
for computation of xid horizon that avoid reporting of false errors.
However, GetStrictOldestNonRemovableTransactionId() uses
GetRunningTransactionData() even on standby leading to an assertion failure.
Given that we decided to ignore KnownAssignedXids and standby can't have
own running xids, we switch to use TransamVariables->nextXid as a xid horizon.
Also, revise the comment regarding ignoring KnownAssignedXids with more
detailed reasoning provided by Heikki.
Reported-by: Heikki Linnakangas
Discussion: https://postgr.es/m/42218c4f-2c8d-40a3-8743-4d34dd0e4cce%40iki.fi
Reviewed-by: Heikki Linnakangas
Prior to commit 0709b7ee72, which changed the spinlock primitives
to function as compiler barriers, access to variables within a
spinlock-protected section required using a volatile pointer, but
that is no longer necessary.
Reviewed-by: Bertrand Drouvot, Michael Paquier
Discussion: https://postgr.es/m/Zqkv9iK7MkNS0KaN%40nathan
When pg_dump retrieves the list of database objects and performs the
data dump, there was possibility that objects are replaced with others
of the same name, such as views, and access them. This vulnerability
could result in code execution with superuser privileges during the
pg_dump process.
This issue can arise when dumping data of sequences, foreign
tables (only 13 or later), or tables registered with a WHERE clause in
the extension configuration table.
To address this, pg_dump now utilizes the newly introduced
restrict_nonsystem_relation_kind GUC parameter to restrict the
accesses to non-system views and foreign tables during the dump
process. This new GUC parameter is added to back branches too, but
these changes do not require cluster recreation.
Back-patch to all supported branches.
Reviewed-by: Noah Misch
Security: CVE-2024-7348
Backpatch-through: 12
Before Bison 3.4, the generated parser implementation files run afoul
of -Wmissing-variable-declarations (in spite of commit ab61c40bfa)
because declarations for yylval and possibly yylloc are missing. The
generated header files contain an extern declaration, but the
implementation files don't include the header files. Since Bison 3.4,
the generated implementation files automatically include the generated
header files, so then it works.
To make this work with older Bison versions as well, include the
generated header file from the .y file.
(With older Bison versions, the generated implementation file contains
effectively a copy of the header file pasted in, so including the
header file is redundant. But we know this works anyway because the
core grammar uses this arrangement already.)
Discussion: https://www.postgresql.org/message-id/flat/e0a62134-83da-4ba4-8cdb-ceb0111c95ce@eisentraut.org
The buffer is used only locally within the function. Also, the
initialization to '0' characters was unnecessary, the initial content
were always overwritten with sprintf(). I don't understand why it was
done that way, but it's been like that since forever.
In the passing, change from sprintf() to snprintf(). The buffer was
long enough so sprintf() was fine, but this makes it more obvious that
there's no risk of a buffer overflow.
Reviewed-by: Robert Haas
Discussion: https://www.postgresql.org/message-id/7f86e06a-98c5-4ce3-8ec9-3885c8de0358@iki.fi
Currently, when amcheck validates a unique constraint, it visits the heap for
each index tuple. This commit implements skipping keys, which have only one
non-dedeuplicated index tuple (quite common case for unique indexes). That
gives substantial economy on index checking time.
Reported-by: Noah Misch
Discussion: https://postgr.es/m/20240325020323.fd.nmisch%40google.com
Author: Alexander Korotkov, Pavel Borisov
There were quite a few places where we either had a non-NUL-terminated
string or a text Datum which we needed to call escape_json() on. Many of
these places required that a temporary string was created due to the fact
that escape_json() needs a NUL-terminated cstring. For text types, those
first had to be converted to cstring before calling escape_json() on them.
Here we introduce two new functions to make escaping JSON more optimal:
escape_json_text() can be given a text Datum to append onto the given
buffer. This is more optimal as it foregoes the need to convert the text
Datum into a cstring. A temporary allocation is only required if the text
Datum needs to be detoasted.
escape_json_with_len() can be used when the length of the cstring is
already known or the given string isn't NUL-terminated. Having this
allows various places which were creating a temporary NUL-terminated
string to just call escape_json_with_len() without any temporary memory
allocations.
Discussion: https://postgr.es/m/CAApHDvpLXwMZvbCKcdGfU9XQjGCDm7tFpRdTXuB9PVgpNUYfEQ@mail.gmail.com
Reviewed-by: Melih Mutlu, Heikki Linnakangas
The buildfarm member "hake" reported a failure in the regression test
added by commit 857df3cef7, where postgres_fdw_get_connections(true)
returned unexpected results.
The function postgres_fdw_get_connections(true) checks
if a connection is closed by using POLLRDHUP in the requested events
and calling poll(). Previously, the function only considered
POLLRDHUP or 0 as valid returned events. However, poll() can also
return POLLHUP, POLLERR, and/or POLLNVAL. So if any of these events
were returned, postgres_fdw_get_connections(true) would report
incorrect results. postgres_fdw_get_connections(true) failed to
account for these return events.
This commit updates postgres_fdw_get_connections(true) to correctly
report a closed connection when poll() returns not only POLLRDHUP
but also POLLHUP, POLLERR, or POLLNVAL.
Discussion: https://postgr.es/m/fd8f6186-9e1e-4b9a-92c5-e71e3697d381@oss.nttdata.com
This commit extends the postgres_fdw_get_connections() function
to check if connections are closed. This is useful for detecting closed
postgres_fdw connections that could prevent successful transaction
commits. Users can roll back transactions immediately upon detecting
closed connections, avoiding unnecessary processing of failed
transactions.
This feature is available only on systems supporting the non-standard
POLLRDHUP extension to the poll system call, including Linux.
Author: Hayato Kuroda
Reviewed-by: Shinya Kato, Zhihong Yu, Kyotaro Horiguchi, Andres Freund
Reviewed-by: Onder Kalaci, Takamichi Osumi, Vignesh C, Tom Lane, Ted Yu
Reviewed-by: Katsuragi Yuta, Peter Smith, Shubham Khanna, Fujii Masao
Discussion: https://postgr.es/m/TYAPR01MB58662809E678253B90E82CE5F5889@TYAPR01MB5866.jpnprd01.prod.outlook.com
This commit extends the postgres_fdw_get_connections() function to
include a new used_in_xact column, indicating whether each connection
is used in the current transaction.
This addition is particularly useful for the upcoming feature that
will check if connections are closed. By using those information,
users can verify if postgres_fdw connections used in a transaction
remain open. If any connection is closed, the transaction cannot
be committed successfully. In this case users can roll back it
immediately without waiting for transaction end.
The SQL API for postgres_fdw_get_connections() is updated by
this commit and may change in the future. To handle compatibility
with older SQL declarations, an API versioning system is introduced,
allowing the function to behave differently based on the API version.
Author: Hayato Kuroda
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/be9382f7-5072-4760-8b3f-31d6dffa8d62@oss.nttdata.com
This change allows these functions to be called using named-argument
notation, which can be helpful for readability, particularly for
the ones with many arguments.
There was considerable debate about exactly which names to use,
but in the end we settled on the names already shown in our
documentation table 9.10.
The citext extension provides citext-aware versions of some of
these functions, so add argument names to those too.
In passing, fix table 9.10's syntax synopses for regexp_match,
which were slightly wrong about which combinations of arguments
are allowed.
Jian He, reviewed by Dian Fay and others
Discussion: https://postgr.es/m/CACJufxG3NFKKsh6x4fRLv8h3V-HvN4W5dA=zNKMxsNcDwOKang@mail.gmail.com
This adds extern declarations for some global variables produced by
Bison that are not already declared in its generated header file.
This is a workaround to be able to add -Wmissing-variable-declarations
to the global set of warning options in the near future.
Another longer-term solution would be to convert these grammars to
"pure" parsers in Bison, to avoid global variables altogether. Note
that the core grammar is already pure, so this patch did not need to
touch it.
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/flat/e0a62134-83da-4ba4-8cdb-ceb0111c95ce@eisentraut.org
This commit adds a regression test to verify that pg_stat_statements
correctly handles privileges, improving its test coverage.
Author: Keisuke Kuroda
Reviewed-by: Michael Paquier, Fujii Masao
Discussion: https://postgr.es/m/2224ccf2e12c41ccb81702ef3303d5ac@nttcom.co.jp
Commit d844cd75a disallowed rewind in a non-scrollable cursor to resolve
anomalies arising from such a cursor operation. However, this failed to
take into account the assumption in postgres_fdw that when rescanning a
foreign relation, it can rewind the cursor created for scanning the
foreign relation without specifying the SCROLL option, regardless of its
scrollability, causing this error when it tried to do such a rewind in a
non-scrollable cursor. Fix by modifying postgres_fdw to instead
recreate the cursor, regardless of its scrollability, when rescanning
the foreign relation. (If we had a way to check its scrollability, we
could improve this by rewinding it if it is scrollable and recreating it
if not, but we do not have it, so this commit modifies it to recreate it
in any case.)
Per bug #17889 from Eric Cyr. Devrim Gunduz also reported this problem.
Back-patch to v15 where that commit enforced the prohibition.
Reviewed by Tom Lane.
Discussion: https://postgr.es/m/17889-e8c39a251d258dda%40postgresql.org
Discussion: https://postgr.es/m/b415ac3255f8352d1ea921cf3b7ba39e0587768a.camel%40gunduz.org
For utility statements defined within a function, the query tree is
copied to a PlannedStmt as utility commands do not require planning.
However, the query ID was missing from the information passed down.
This leads to plugins relying on the query ID like pg_stat_statements to
not be able to track utility statements within function calls. Tests
are added to check this behavior, depending on pg_stat_statements.track.
This is an old bug. Now, query IDs for utilities are compiled using
their parsed trees rather than the query string since v16
(3db72ebcbe), leading to less bloat with utilities, so backpatch down
only to this version.
Author: Anthonin Bonnefoy
Discussion: https://postgr.es/m/CAO6_XqrGp-uwBqi3vBPLuRULKkddjC7R5QZCgsFren=8E+m2Sg@mail.gmail.com
Backpatch-through: 16
If we intend to generate a Memoize node on top of a path, we need
cache keys of some sort. Currently we search for the cache keys in
the parameterized clauses of the path as well as the lateral_vars of
its parent. However, it turns out that this is not sufficient because
there might be lateral references derived from PlaceHolderVars, which
we fail to take into consideration.
This oversight can cause us to miss opportunities to utilize the
Memoize node. Moreover, in some plans, failing to recognize all the
cache keys could result in performance regressions. This is because
without identifying all the cache keys, we would need to purge the
entire cache every time we get a new outer tuple during execution.
This patch fixes this issue by extracting lateral Vars from within
PlaceHolderVars and subsequently including them in the cache keys.
In passing, this patch also includes a comment clarifying that Memoize
nodes are currently not added on top of join relation paths. This
explains why this patch only considers PlaceHolderVars that are due to
be evaluated at baserels.
Author: Richard Guo
Reviewed-by: Tom Lane, David Rowley, Andrei Lepikhov
Discussion: https://postgr.es/m/CAMbWs48jLxn0pAPZpJ50EThZ569Xrw+=4Ac3QvkpQvNszbeoNg@mail.gmail.com
When creating and initializing a logical slot, the restart_lsn is set
to the latest WAL insertion point (or the latest replay point on
standbys). Subsequently, WAL records are decoded from that point to
find the start point for extracting changes in the
DecodingContextFindStartpoint() function. Since the initial
restart_lsn could be in the middle of a transaction, the start point
must be a consistent point where we won't see the data for partial
transactions.
Previously, when not building a full snapshot, serialized snapshots
were restored, and the SnapBuild jumps to the consistent state even
while finding the start point. Consequently, the slot's restart_lsn
and confirmed_flush could be set to the middle of a transaction. This
could lead to various unexpected consequences. Specifically, there
were reports of logical decoding decoding partial transactions, and
assertion failures occurred because only subtransactions were decoded
without decoding their top-level transaction until decoding the commit
record.
To resolve this issue, the changes prevent restoring the serialized
snapshot and jumping to the consistent state while finding the start
point.
On v17 and HEAD, a flag indicating whether snapshot restores should be
skipped has been added to the SnapBuild struct, and SNAPBUILD_VERSION
has been bumpded.
On backbranches, the flag is stored in the LogicalDecodingContext
instead, preserving on-disk compatibility.
Backpatch to all supported versions.
Reported-by: Drew Callahan
Reviewed-by: Amit Kapila, Hayato Kuroda
Discussion: https://postgr.es/m/2444AA15-D21B-4CCE-8052-52C7C2DAFE5C%40amazon.com
Backpatch-through: 12
Previously we searched for code points where the Unicode data file
listed an equivalent combining character sequence that added accents.
Some codepoints redirect to a single other codepoint, instead of doing
any combining. We can follow those references recursively to get the
answer.
Per bug report #18362, which reported missing Ancient Greek characters.
Specifically, precomposed characters with oxia (from the polytonic
accent system used for old Greek) just point to precomposed characters
with tonos (from the monotonic accent system for modern Greek), and we
have to follow the extra hop to find out that they are composed with
an acute accent.
Besides those, the new rule also:
* pulls in a lot of 'Mathematical Alphanumeric Symbols', which are
copies of the Latin and Greek alphabets and numbers rendered
in different typefaces, and
* corrects a single mathematical letter that previously came from the
CLDR transliteration file, but the new rule extracts from the main
Unicode database file, where clearly the latter is right and the
former is a wrong (reported to CLDR).
Reported-by: Cees van Zeeland <cees.van.zeeland@freedom.nl>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/18362-be6d0cfe122b6354%40postgresql.org
Hash joins can support semijoin with the LHS input on the right, using
the existing logic for inner join, combined with the assurance that only
the first match for each inner tuple is considered, which can be
achieved by leveraging the HEAP_TUPLE_HAS_MATCH flag. This can be very
useful in some cases since we may now have the option to hash the
smaller table instead of the larger.
Merge join could likely support "Right Semi Join" too. However, the
benefit of swapping inputs tends to be small here, so we do not address
that in this patch.
Note that this patch also modifies a test query in join.sql to ensure it
continues testing as intended. With this patch the original query would
result in a right-semi-join rather than semi-join, compromising its
original purpose of testing the fix for neqjoinsel's behavior for
semi-joins.
Author: Richard Guo
Reviewed-by: wenhui qiu, Alena Rybakina, Japin Li
Discussion: https://postgr.es/m/CAMbWs4_X1mN=ic+SxcyymUqFx9bB8pqSLTGJ-F=MHy4PW3eRXw@mail.gmail.com
All the errors triggered in the code paths patched here would cause the
backend to issue an internal_error errcode, which is a state that should
be used only for "can't happen" situations. However, these code paths
are reachable by the regression tests, and could be seen by users in
valid cases. Some regression tests expect internal errcodes as they
manipulate the backend state to cause corruption (like checksums), or
use elog() because it is more convenient (like injection points), these
have no need to change.
This reduces the number of internal failures triggered in a check-world
by more than half, while providing correct errcodes for these valid
cases.
Reviewed-by: Robert Haas
Discussion: https://postgr.es/m/Zic_GNgos5sMxKoa@paquier.xyz
This commit removes unused variables and routines from some perl code
that have accumulated across the years. This touches the following
areas:
- Wait event generation script.
- AdjustUpgrade.pm.
- TAP perl code
Author: Alexander Lakhin
Reviewed-by: Dagfinn Ilmari Mannsåker
Discussion: https://postgr.es/m/70b340bc-244a-589d-ef8b-d8aebb707a84@gmail.com
This old CPU architecture hasn't been produced in decades, and
whatever instances might still survive are surely too underpowered
for anyone to consider running Postgres on in production. We'd
nonetheless continued to carry code support for it (largely at my
insistence), because its unique implementation of spinlocks seemed
like a good edge case for our spinlock infrastructure. However,
our last buildfarm animal of this type was retired last year, and
it seems quite unlikely that another will emerge. Without the ability
to run tests, the argument that this is useful test code fails to
hold water. Furthermore, carrying code support for an untestable
architecture has costs not to be ignored. So, remove HPPA-specific
code, in the same vein as commits 718aa43a4 and 92d70b77e.
Discussion: https://postgr.es/m/3351991.1697728588@sss.pgh.pa.us
Previously, when considering LIMIT pushdown, postgres_fdw failed to
check whether the query has this clause, which led to pushing false
LIMIT clauses, causing incorrect results.
This clause has been supported since v13, so we need to do a
remote-version check before deciding that it will be safe to push such a
clause, but we do not currently have a way to do the check (without
accessing the remote server); disable pushing such a clause for now.
Oversight in commit 357889eb1. Back-patch to v13, where that commit
added the support.
Per bug #18467 from Onder Kalaci.
Patch by Japin Li, per a suggestion from Tom Lane, with some changes to
the comments by me. Review by Onder Kalaci, Alvaro Herrera, and me.
Discussion: https://postgr.es/m/18467-7bb89084ff03a08d%40postgresql.org
ReorderBufferImmediateInvalidation() executes invalidation messages in
an aborted transaction. However, RelationFlushRelation sometimes
required a valid resource owner, to temporarily increment the refcount
of the relache entry. Commit b8bff07daa worked around that in the main
subtransaction abort function, AbortSubTransaction(), but missed this
similar case in ReorderBufferImmediateInvalidation().
To fix, introduce a separate function to invalidate a relcache
entry. It does the same thing as RelationClearRelation(rebuild==true)
does when outside a transaction, but can be called without
incrementing the refcount.
Add regression test. Before this fix, it failed with:
ERROR: ResourceOwnerEnlarge called after release started
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://www.postgresql.org/message-id/e56be7d9-14b1-664d-0bfc-00ce9772721c@gmail.com
* Don't forget to pfree() the right page when it's to be ignored.
* Report error on unexpected non-leaf right page even if this page is not
to be ignored. This restores the logic which was unintendedly changed
in 97e5b0026f.
Reported-by: Pavel Borisov
This is a very unlikely condition during checking a B-tree unique constraint,
meaning that the index structure is violated badly, and we shouldn't continue
checking to avoid endless loops, etc. So it's worth immediately throwing an
error.
Reported-by: Peter Geoghegan
Discussion: https://postgr.es/m/CAH2-Wzk%2B2116uOXdOViA27SHcr31WKPgmjsxXLBs_aTxAeThzg%40mail.gmail.com
Author: Pavel Borisov
5ae2087202 implemented a cross-page unique constraint check by loading
the right sibling to the BtreeCheckState.target variable. This is wrong,
because bt_target_page_check() shouldn't change the target page. Also,
BtreeCheckState.target shouldn't be changed alone without
BtreeCheckState.targetblock.
However, the above didn't cause any visible bugs for the following reasons.
1. We do a cross-page unique constraint check only for leaf index pages.
2. The only way target page get accessed after a cross-page unique constraint
check is loading of the lowkey.
3. The only place lowkey is used is bt_child_highkey_check(), and that applies
only to non-leafs.
The reasons above don't diminish the fact that changing BtreeCheckState.target
for a cross-page unique constraint check is wrong. This commit changes this
check to temporarily store the right sibling to the local variable.
Reported-by: Peter Geoghegan
Discussion: https://postgr.es/m/CAH2-Wzk%2B2116uOXdOViA27SHcr31WKPgmjsxXLBs_aTxAeThzg%40mail.gmail.com
Author: Pavel Borisov
This commit introduces a new data structure BtreeLastVisibleEntry comprising
information about the last visible heap entry with the current value of key.
Usage of this data structure allows us to avoid passing all this information
as individual function arguments.
Reported-by: Alexander Korotkov
Discussion: https://www.postgresql.org/message-id/CAPpHfdsVbB9ToriaB1UHuOKwjKxiZmTFQcEF%3DjuzzC_nby31uA%40mail.gmail.com
Author: Pavel Borisov, Alexander Korotkov
This reverts commit 7204f35919,
thus restoring 66c0185a3 (Allow planner to use Merge Append to
efficiently implement UNION) as well as the follow-on commits
d5d2205c8, 3b1a7eb28, 7487044d6.
Per further discussion on pgsql-release, we wish to ship beta1 with
this feature, and patch the bug that was found just before wrap,
rather than shipping beta1 with the feature reverted.
This reverts 66c0185a3 (Allow planner to use Merge Append to
efficiently implement UNION) as well as the follow-on commits
d5d2205c8, 3b1a7eb28, 7487044d6. In addition to those, 07746a8ef
had to be removed then re-applied in a different place, because
66c0185a3 moved the relevant code.
The reason for this last-minute thrashing is that depesz found a
case in which the patched code creates a completely wrong plan
that silently gives incorrect query results. It's unclear what
the cause is or how many cases are affected, but with beta1 wrap
staring us in the face, there's no time for closer investigation.
After we figure that out, we can decide whether to un-revert this
for beta2 or hold it for v18.
Discussion: https://postgr.es/m/Zktzf926vslR35Fv@depesz.com
(also some private discussion among pgsql-release)
Tom Lane