pread() and pwrite() are in SUSv2, and all targeted Unix systems have
them.
Previously, we defined pg_pread and pg_pwrite to emulate these function
with lseek() on old Unixen. The names with a pg_ prefix were a reminder
of a portability hazard: they might change the current file position.
That hazard is gone, so we can drop the prefixes.
Since the remaining replacement code is Windows-only, move it into
src/port/win32p{read,write}.c, and move the declarations into
src/include/port/win32_port.h.
No need for vestigial HAVE_PREAD, HAVE_PWRITE macros as they were only
used for declarations in port.h which have now moved into win32_port.h.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Greg Stark <stark@mit.edu>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA+hUKGJ3LHeP9w5Fgzdr4G8AnEtJ=z=p6hGDEm4qYGEUX5B6fQ@mail.gmail.com
setenv() and unsetenv() are in SUSv3 and targeted Unix systems have
them. We still need special code for these on Windows, but that doesn't
require a configure probe.
This marks the first time we require a SUSv3 (POSIX.1-2001) facility
(rather than SUSv2). The replacement code removed here was not needed
on any targeted system or any known non-EOL'd Unix system, and was
therefore dead and untested.
No need for vestigial HAVE_SETENV and HAVE_UNSETENV macros, because we
provide a replacement for Windows, and we didn't previously test the
macros.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Greg Stark <stark@mit.edu>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA+hUKGJ3LHeP9w5Fgzdr4G8AnEtJ=z=p6hGDEm4qYGEUX5B6fQ@mail.gmail.com
poll() and <poll.h> are in SUSv2 and all targeted Unix systems have
them.
Retain HAVE_POLL and HAVE_POLL_H macros for readability. There's an
error in latch.c that is now unreachable (since we always have one of
WIN32 or HAVE_POLL defined), but that falls out of a decision to keep
using defined(HAVE_POLL) instead of !defined(WIN32) to guard the poll()
code.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA+hUKGJ3LHeP9w5Fgzdr4G8AnEtJ=z=p6hGDEm4qYGEUX5B6fQ@mail.gmail.com
link() is in SUSv2 and all targeted Unix systems have it. We have
replacement code for Windows that doesn't require a configure probe.
Since only Windows needs it, rename src/port/link.c to win32link.c like
other similar things.
There is no need for a vestigial HAVE_LINK macro, because we expect all
Unix and, with our replacement function, Windows systems to have it, so
we didn't have any tests around link() usage.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA+hUKGJ3LHeP9w5Fgzdr4G8AnEtJ=z=p6hGDEm4qYGEUX5B6fQ@mail.gmail.com
symlink() and readlink() are in SUSv2 and all targeted Unix systems have
them. We have partial emulation on Windows. Code that raised runtime
errors on systems without it has been dead for years, so we can remove
that and also references to such systems in the documentation.
Define HAVE_READLINK and HAVE_SYMLINK macros on Unix. Our Windows
replacement functions based on junction points can't be used for
relative paths or for non-directories, so the macros can be used to
check for full symlink support. The places that deal with tablespaces
can just use symlink functions without checking the macros. (If they
did check the macros, they'd need to provide an #else branch with a
runtime or compile time error, and it'd be dead code.)
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA+hUKGJ3LHeP9w5Fgzdr4G8AnEtJ=z=p6hGDEm4qYGEUX5B6fQ@mail.gmail.com
setsid() is in SUSv2 and all targeted Unix systems have it. Retain a
HAVE_SETSID macro, defined on Unix only. That's easier to understand
than !defined(WIN32), for the optional code it governs.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA+hUKGJ3LHeP9w5Fgzdr4G8AnEtJ=z=p6hGDEm4qYGEUX5B6fQ@mail.gmail.com
shm_open() is in SUSv2 and all targeted Unix systems have it.
We retain a HAVE_SHM_OPEN macro, because it's clearer to readers than
something like !defined(WIN32).
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA+hUKGJ3LHeP9w5Fgzdr4G8AnEtJ=z=p6hGDEm4qYGEUX5B6fQ@mail.gmail.com
getrlimit() is in SUSv2 and all targeted systems have it.
Windows doesn't have it. We could just use #ifndef WIN32, but for a
little more explanation about why we're making things conditional, let's
retain the HAVE_GETRLIMIT macro. It's defined in port.h for Unix systems.
On systems that have it, it's not necessary to test for RLIMIT_CORE,
RLIMIT_STACK or RLIMIT_NOFILE macros, since SUSv2 requires those and all
targeted systems have them. Also remove references to a pre-historic
alternative spelling of RLIMIT_NOFILE, and coding that seemed to believe
that Cygwin didn't have it.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA+hUKGJ3LHeP9w5Fgzdr4G8AnEtJ=z=p6hGDEm4qYGEUX5B6fQ@mail.gmail.com
dlopen() is in SUSv2 and all targeted Unix systems have it. We still
need replacement functions for Windows, but we don't need a configure
probe for that.
Since it's no longer needed by other operating systems, rename dlopen.c
to win32dlopen.c and move the declarations into win32_port.h.
Likewise, the macros RTLD_NOW and RTLD_GLOBAL now only need to be
defined on Windows, since all targeted Unix systems have 'em.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA+hUKGJ3LHeP9w5Fgzdr4G8AnEtJ=z=p6hGDEm4qYGEUX5B6fQ@mail.gmail.com
SSE2 vector instructions are part of the spec for the 64-bit x86
architecture. Until now we have relied on the compiler to autovectorize
in some limited situations, but some useful coding idioms can only be
expressed explicitly via compiler intrinsics. To this end, add a header
that defines USE_SSE2 where available. While x86-only for now, we can
add other architectures in the future. This will also be the intended
place for helper functions that use vector operations.
Reviewed by Nathan Bossart and Masahiko Sawada
Discussion: https://www.postgresql.org/message-id/CAFBsxsE2G_H_5Wbw%2BNOPm70-BK4xxKf86-mRzY%3DL2sLoQqM%2B-Q%40mail.gmail.com
Commit fac1b470a thought we could check for set-returning functions
by testing only the top-level node in an expression tree. This is
wrong in itself, and to make matters worse it encouraged others
to make the same mistake, by exporting tlist.c's special-purpose
IS_SRF_CALL() as a widely-visible macro. I can't find any evidence
that anyone's taken the bait, but it was only a matter of time.
Use expression_returns_set() instead, and stuff the IS_SRF_CALL()
genie back in its bottle, this time with a warning label. I also
added a couple of cross-reference comments.
After a fair amount of fooling around, I've despaired of making
a robust test case that exposes the bug reliably, so no test case
here. (Note that the test case added by fac1b470a is itself
broken, in that it doesn't notice if you remove the code change.
The repro given by the bug submitter currently doesn't fail either
in v15 or HEAD, though I suspect that may indicate an unrelated bug.)
Per bug #17564 from Martijn van Oosterhout. Back-patch to v13,
as the faulty patch was.
Discussion: https://postgr.es/m/17564-c7472c2f90ef2da3@postgresql.org
ORDER BY / DISTINCT aggreagtes have, since implemented in Postgres, been
executed by always performing a sort in nodeAgg.c to sort the tuples in
the current group into the correct order before calling the transition
function on the sorted tuples. This was not great as often there might be
an index that could have provided pre-sorted input and allowed the
transition functions to be called as the rows come in, rather than having
to store them in a tuplestore in order to sort them once all the tuples
for the group have arrived.
Here we change the planner so it requests a path with a sort order which
supports the most amount of ORDER BY / DISTINCT aggregate functions and
add new code to the executor to allow it to support the processing of
ORDER BY / DISTINCT aggregates where the tuples are already sorted in the
correct order.
Since there can be many ORDER BY / DISTINCT aggregates in any given query
level, it's very possible that we can't find an order that suits all of
these aggregates. The sort order that the planner chooses is simply the
one that suits the most aggregate functions. We take the most strictly
sorted variation of each order and see how many aggregate functions can
use that, then we try again with the order of the remaining aggregates to
see if another order would suit more aggregate functions. For example:
SELECT agg(a ORDER BY a),agg2(a ORDER BY a,b) ...
would request the sort order to be {a, b} because {a} is a subset of the
sort order of {a,b}, but;
SELECT agg(a ORDER BY a),agg2(a ORDER BY c) ...
would just pick a plan ordered by {a} (we give precedence to aggregates
which are earlier in the targetlist).
SELECT agg(a ORDER BY a),agg2(a ORDER BY b),agg3(a ORDER BY b) ...
would choose to order by {b} since two aggregates suit that vs just one
that requires input ordered by {a}.
Author: David Rowley
Reviewed-by: Ronan Dunklau, James Coleman, Ranier Vilela, Richard Guo, Tom Lane
Discussion: https://postgr.es/m/CAApHDvpHzfo92%3DR4W0%2BxVua3BUYCKMckWAmo-2t_KiXN-wYH%3Dw%40mail.gmail.com
Here we add code which detects when ExecFindPartition() continually finds
the same partition and add a caching layer to improve partition lookup
performance for such cases.
Both RANGE and LIST partitioned tables traditionally require a binary
search for the set of Datums that a partition needs to be found for. This
binary search is commonly visible in profiles when bulk loading into a
partitioned table. Here we aim to reduce the overhead of bulk-loading
into partitioned tables for cases where many consecutive tuples belong to
the same partition and make the performance of this operation closer to
what it is with a traditional non-partitioned table.
When we find the same partition 16 times in a row, the next search will
result in us simply just checking if the current set of values belongs to
the last found partition. For LIST partitioning we record the index into
the PartitionBoundInfo's datum array. This allows us to check if the
current Datum is the same as the Datum that was last looked up. This
means if any given LIST partition supports storing multiple different
Datum values, then the caching only works when we find the same value as
we did the last time. For RANGE partitioning we simply check if the given
Datums are in the same range as the previously found partition.
We store the details of the cached partition in PartitionDesc (i.e.
relcache) so that the cached values are maintained over multiple
statements.
No caching is done for HASH partitions. The majority of the cost in HASH
partition lookups are in the hashing function(s), which would also have to
be executed if we were to try to do caching for HASH partitioned tables.
Since most of the cost is already incurred, we just don't bother. We also
don't do any caching for LIST partitions when we continually find the
values being looked up belong to the DEFAULT partition. We've no
corresponding index in the PartitionBoundInfo's datum array for this case.
We also don't cache when we find the given values match to a LIST
partitioned table's NULL partition. This is so cheap that there's no
point in doing any caching for this. We also don't cache for a RANGE
partitioned table's DEFAULT partition.
There have been a number of different patches submitted to improve
partition lookups. Hou, Zhijie submitted a patch to detect when the value
belonging to the partition key column(s) were constant and added code to
cache the partition in that case. Amit Langote then implemented an idea
suggested by me to remember the last found partition and start to check if
the current values work for that partition. The final patch here was
written by me and was done by taking many of the ideas I liked from the
patches in the thread and redesigning other aspects.
Discussion: https://postgr.es/m/OS0PR01MB571649B27E912EA6CC4EEF03942D9%40OS0PR01MB5716.jpnprd01.prod.outlook.com
Author: Amit Langote, Hou Zhijie, David Rowley
Reviewed-by: Amit Langote, Hou Zhijie
There wasn't an especially nice way to read all of a file while
passing missing_ok = true. Add an additional overloaded variant
to support that use-case.
While here, refactor the C code to avoid a rats-nest of PG_NARGS
checks, instead handling the argument collection in the outer
wrapper functions. It's a bit longer this way, but far more
straightforward.
(Upon looking at the code coverage report for genfile.c, I was
impelled to also add a test case for pg_stat_file() -- tgl)
Kyotaro Horiguchi
Discussion: https://postgr.es/m/20220607.160520.1984541900138970018.horikyota.ntt@gmail.com
Commit b0a55e4329 missed a few places
where we are referring to the number used as a part of the relation
filename as an "OID". We now want to call that a "RelFileNumber".
Some of these places actually made it sound like the OID in question
is pg_class.oid rather than pg_class.relfilenode, which is especially
good to clean up.
Dilip Kumar with some editing by me.
The catalog contents haven't changed, but it's good to make clear
that initdb is required. Changing RELMAPPER_FILEMAGIC would be more
appropriate, but that doesn't actually produce a useful diagnostic,
so cheat by doing this instead.
Discussion: http://postgr.es/m/20220727171939.6ixixqcjt5riil2o@alvherre.pgsql
GetSubscriptionRelations() and GetSubscriptionNotReadyRelations() share
mostly the same code, which scans pg_subscription_rel and fetches all
the relations of a given subscription. The only difference is that the
second routine looks for all the relations not in a ready state. This
commit refactors the code to use a single routine, shaving a bit of
code.
Author: Vignesh C
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Michael Paquier, Peter
Smith
Discussion: https://postgr.es/m/CALDaNm0eW-9g4G_EzHebnFT5zZoasWCS_EzZQ5BgnLZny9S=pg@mail.gmail.com
This commit puts the implementation of Tuple sort variants into the separate
file tuplesortvariants.c. That gives better separation of the code and
serves well as the demonstration that Tuple sort variant can be defined outside
of tuplesort.c.
Discussion: https://postgr.es/m/CAPpHfdvjix0Ahx-H3Jp1M2R%2B_74P-zKnGGygx4OWr%3DbUQ8BNdw%40mail.gmail.com
Author: Alexander Korotkov
Reviewed-by: Pavel Borisov, Maxim Orlov, Matthias van de Meent
Reviewed-by: Andres Freund, John Naylor
XLogRecordBlockHeader, the header holding the information for the data
related to a block, tracks the length of the data appended to the WAL
record with data_length (uint16). This limitation in size was not
enforced by the public routine in charge of registering the data
assembled later to form the WAL record inserted, XLogRegisterBufData().
Incorrectly used, it could lead to the generation of records with some
of its data overflowed. This commit adds some safeguards to prevent
that for the block data, complaining immediately if attempting to add to
a record block information with a size larger than UINT16_MAX, which is
the limit implied by the internal logic.
Note that this also adjusts XLogRegisterData() and XLogRegisterBufData()
so as the length of the WAL record data given by the caller is unsigned,
matching with what gets stored in XLogRecData->len.
Extracted from a larger patch by the same author. The original patch
includes more protections when assembling a record in full that will be
looked at separately later.
Author: Matthias van de Meent
Reviewed-by: Andres Freund, Heikki Linnakangas, Michael Paquier, David
Zhang
Discussion: https://postgr.es/m/CAEze2WgGiw+LZt+vHf8tWqB_6VxeLsMeoAuod0N=ij1q17n5pw@mail.gmail.com
We have a few commands that "can't run in a transaction block",
meaning that if they complete their processing but then we fail
to COMMIT, we'll be left with inconsistent on-disk state.
However, the existing defenses for this are only watertight for
simple query protocol. In extended protocol, we didn't commit
until receiving a Sync message. Since the client is allowed to
issue another command instead of Sync, we're in trouble if that
command fails or is an explicit ROLLBACK. In any case, sitting
in an inconsistent state while waiting for a client message
that might not come seems pretty risky.
This case wasn't reachable via libpq before we introduced pipeline
mode, but it's always been an intended aspect of extended query
protocol, and likely there are other clients that could reach it
before.
To fix, set a flag in PreventInTransactionBlock that tells
exec_execute_message to force an immediate commit. This seems
to be the approach that does least damage to existing working
cases while still preventing the undesirable outcomes.
While here, add some documentation to protocol.sgml that explicitly
says how to use pipelining. That's latent in the existing docs if
you know what to look for, but it's better to spell it out; and it
provides a place to document this new behavior.
Per bug #17434 from Yugo Nagata. It's been wrong for ages,
so back-patch to all supported branches.
Discussion: https://postgr.es/m/17434-d9f7a064ce2a88a3@postgresql.org
The setting controls tha maximum length of the header line in expanded
format output. Possible settings are full, column, page, or an integer.
the default is full, the current behaviour, and in this case the header
line is the length of the widest line of output. column causes the
header to be truncated to the width of the first column, page causes it
to be truncated to the width of the terminal page, and an integer causes
it to be truncated to that value. If the full value is less than the
page or integer value no truncation occurs. If given without an argument
this option prints its current setting.
Platon Pronko, somewhat modified by me.
Discussion: https://postgr.es/m/f03d38a3-db96-a56e-d1bc-dbbc80bbde4d@gmail.com
Previously we did this after InitPostgres, at a somewhat randomly chosen
place within PostgresMain. However, since commit a0ffa885e doing this
outside a transaction can cause a crash, if we need to check permissions
while replacing a placeholder GUC. (Besides which, a preloaded library
could itself want to do database access within _PG_init.)
To avoid needing an additional transaction start/end in every session,
move the process_session_preload_libraries call to within InitPostgres's
transaction. That requires teaching the code not to call it when
InitPostgres is called from somewhere other than PostgresMain, since
we don't want session_preload_libraries to affect background workers.
The most future-proof solution here seems to be to add an additional
flag parameter to InitPostgres; fortunately, we're not yet very worried
about API stability for v15.
Doing this also exposed the fact that we're currently honoring
session_preload_libraries in walsenders, even those not connected to
any database. This seems, at minimum, a POLA violation: walsenders
are not interactive sessions. Let's stop doing that.
(All these comments also apply to local_preload_libraries, of course.)
Per report from Gurjeet Singh (thanks also to Nathan Bossart and Kyotaro
Horiguchi for review). Backpatch to v15 where a0ffa885e came in.
Discussion: https://postgr.es/m/CABwTF4VEpwTHhRQ+q5MiC5ucngN-whN-PdcKeufX7eLSoAfbZA@mail.gmail.com
sigwait() is in SUSv2 and all targeted Unix systems have it. An earlier
pre-standard function prototype existed on some older systems, but we
no longer need a workaround for that.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Greg Stark <stark@mit.edu>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/CA+hUKGJ3LHeP9w5Fgzdr4G8AnEtJ=z=p6hGDEm4qYGEUX5B6fQ@mail.gmail.com
getrusage() is in SUSv2 and all targeted Unix systems have it.
Note that POSIX only covers ru_utime and ru_stime and we rely on many
more fields without any kind of configure probe, but that predates this
commit.
The only supported system we need replacement code for now is Windows,
and that can be done without a configure probe.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Greg Stark <stark@mit.edu>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/CA+hUKGJ3LHeP9w5Fgzdr4G8AnEtJ=z=p6hGDEm4qYGEUX5B6fQ@mail.gmail.com
O_FSYNC was a pre-POSIX way of spelling O_SYNC, supported since commit
9d645fd84c for non-conforming operating systems of the time. It's not
needed on any modern system. We can just use standard O_SYNC directly
if it exists (= all targeted systems except Windows), and get rid of our
OPEN_SYNC_FLAG macro.
Similarly for standard O_DSYNC, we can just use that directly if it
exists (= all targeted systems except DragonFlyBSD), and get rid of our
OPEN_DATASYNC_FLAG macro.
We still avoid choosing open_datasync as a default value for
wal_sync_method if O_DSYNC has the same value as O_SYNC (= only
OpenBSD), so there is no change in default behavior.
Discussion: https://postgr.es/m/CA%2BhUKGJE7y92NY7FG2ftUbZUaqohBU65_Ys_7xF5mUHo4wirTQ%40mail.gmail.com
Commit 4f658dc8 provided the traditional BSD fls() function in
src/port/fls.c so it could be used in several places. Later we added a
bunch of similar facilities in pg_bitutils.h, based on compiler
builtins that map to hardware instructions. It's a bit confusing to
have both 1-based and 0-based variants of this operation in use in
different parts of the tree, and neither is blessed by a standard.
Let's drop fls.c and the configure probe, and reuse the newer code.
Reviewed-by: David Rowley <dgrowleyml@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CA%2BhUKG%2B7dSX1XF8yFGmYk-%3D48dbjH2kmzZj16XvhbrWP-9BzRg%40mail.gmail.com
This patch adds a new SUBSCRIPTION parameter "origin". It specifies
whether the subscription will request the publisher to only send changes
that don't have an origin or send changes regardless of origin. Setting it
to "none" means that the subscription will request the publisher to only
send changes that have no origin associated. Setting it to "any" means
that the publisher sends changes regardless of their origin. The default
is "any".
Usage:
CREATE SUBSCRIPTION sub1 CONNECTION 'dbname=postgres port=9999'
PUBLICATION pub1 WITH (origin = none);
This can be used to avoid loops (infinite replication of the same data)
among replication nodes.
This feature allows filtering only the replication data originating from
WAL but for initial sync (initial copy of table data) we don't have such a
facility as we can only distinguish the data based on origin from WAL. As
a follow-up patch, we are planning to forbid the initial sync if the
origin is specified as none and we notice that the publication tables were
also replicated from other publishers to avoid duplicate data or loops.
We forbid to allow creating origin with names 'none' and 'any' to avoid
confusion with the same name options.
Author: Vignesh C, Amit Kapila
Reviewed-By: Peter Smith, Amit Kapila, Dilip Kumar, Shi yu, Ashutosh Bapat, Hayato Kuroda
Discussion: https://postgr.es/m/CALDaNm0gwjY_4HFxvvty01BOT01q_fJLKQ3pWP9=9orqubhjcQ@mail.gmail.com
Commit 964d01ae9 marked a lot of fields as read_write_ignore
to stay consistent with what was dumped by the manually-maintained
outfuncs.c code. However, it seems that a pretty fair number
of those omissions were either flat-out oversights, or a shortcut
taken because hand-written code seemed like it'd be too much trouble.
Let's upgrade things where it seems to make sense to dump.
To do this, we need to add support to gen_node_support.pl and
outfuncs.c for variable-length arrays of Node pointers. That's
pretty straightforward given the model of the existing code
for arrays of scalars, but I found I needed to tighten the
type-recognizing regexes in gen_node_support.pl. (As they
stood, they mistook "foo **" for "foo *". Make sure they're
all fully anchored to prevent additional problems.)
The main thing left un-done here is that a lot of partitioning-related
structs are still not dumped, because they are bare structs not Nodes.
I'm not sure about the wisdom of that choice ... but changing it would
be fairly invasive, so it probably requires more justification than
just making planner node dumps more complete.
Discussion: https://postgr.es/m/1295668.1658258637@sss.pgh.pa.us
When the ability to print variable-length-array fields was first
added to outfuncs.c, there was no corresponding read capability,
as it was used only for debug dumps of planner-internal Nodes.
Not a lot of thought seems to have been put into the output format:
it's just the space-separated array elements and nothing else.
Later such fields appeared in Plan nodes, and still later we grew
read support so that Plans could be transferred to parallel workers,
but the original text format wasn't rethought. It seems inadequate
to me because (a) no cross-check is possible that we got the right
number of array entries, (b) we can't tell the difference between
a NULL pointer and a zero-length array, and (c) except for
WRITE_INDEX_ARRAY, we'd crash if a non-zero length is specified
when the pointer is NULL, a situation that can arise in some fields
that we currently conveniently avoid printing.
Since we're currently in a campaign to make the Node infrastructure
generally more it-just-works-without-thinking-about-it, now seems
like a good time to improve this.
Let's adopt a format similar to that used for Lists, that is "<>"
for a NULL pointer or "(item item item)" otherwise. Also retool
the code to not have so many copies of the identical logic.
I bumped catversion out of an abundance of caution, although I think
that we don't use any such array fields in Nodes that can get into
the catalogs.
Discussion: https://postgr.es/m/1528424.1658272135@sss.pgh.pa.us
This allows aliases for sub-SELECTs and VALUES clauses in the FROM
clause to be omitted.
This is an extension of the SQL standard, supported by some other
database systems, and so eases the transition from such systems, as
well as removing the minor inconvenience caused by requiring these
aliases.
Patch by me, reviewed by Tom Lane.
Discussion: https://postgr.es/m/CAEZATCUCGCf82=hxd9N5n6xGHPyYpQnxW8HneeH+uP7yNALkWA@mail.gmail.com
Windows 10 gained support for flushing NTFS files with fdatasync()
semantics. The main advantage over open_datasync (in Windows API terms
FILE_FLAG_WRITE_THROUGH) is that the latter does not flush SATA drive
caches. The default setting is not changed, so users have to opt in to
this.
Discussion: https://postgr.es/m/CA%2BhUKGJZJVO%3DiX%2Beb-PXi2_XS9ZRqnn_4URh0NUQOwt6-_51xQ%40mail.gmail.com
We allow users to set the values of not-yet-loaded extension GUCs,
remembering those values in "placeholder" GUC entries. When/if
the extension is loaded later in the session, we need to verify that
the user had permissions to set the GUC. That was done correctly
before commit a0ffa885e, but as of that commit, we'd check the
permissions of the active role when the LOAD happens, not the role
that had set the value. (This'd be a security bug if it had made it
into a released version.)
In principle this is simple enough to fix: we just need to remember
the exact role OID that set each GUC value, and use that not
GetUserID() when verifying permissions. Maintaining that data in
the guc.c data structures is slightly tedious, but fortunately it's
all basically just copy-n-paste of the logic for tracking the
GucSource of each setting, as we were already doing.
Another oversight is that validate_option_array_item() hadn't
been taught to check for granted GUC privileges. This appears
to manifest only in that ALTER ROLE/DATABASE RESET ALL will
fail to reset settings that the user should be allowed to reset.
Patch by myself and Nathan Bossart, per report from Nathan Bossart.
Back-patch to v15 where the faulty code came in.
Discussion: https://postgr.es/m/20220706224727.GA2158260@nathanxps13
This is mostly just to get outfuncs.c support for them, so that
the agginfos and aggtransinfos lists can be dumped when dumping
the contents of PlannerInfo.
While here, improve some related comments; notably, clean up
obsolete comments left over from when preprocess_minmax_aggregates
had to make its own scan of the query tree.
Discussion: https://postgr.es/m/742479.1658160504@sss.pgh.pa.us
setrefs.c contains logic to discard no-op SubqueryScan nodes, that is,
ones that have no qual to check and copy the input targetlist unchanged.
(Formally it's not very nice to be applying such optimizations so late
in the planner, but there are practical reasons for it; mostly that we
can't unify relids between the subquery and the parent query until we
flatten the rangetable during setrefs.c.) This behavior falsifies our
previous cost estimates, since we would've charged cpu_tuple_cost per
row just to pass data through the node. Most of the time that's little
enough to not matter, but there are cases where this effect visibly
changes the plan compared to what you would've gotten with no
sub-select.
To improve the situation, make the callers of cost_subqueryscan tell
it whether they think the targetlist is trivial. cost_subqueryscan
already has the qual list, so it can check the other half of the
condition easily. It could make its own determination of tlist
triviality too, but doing so would be repetitive (for callers that
may call it several times) or unnecessarily expensive (for callers
that can determine this more cheaply than a general test would do).
This isn't a 100% solution, because createplan.c also does things
that can falsify any earlier estimate of whether the tlist is
trivial. However, it fixes nearly all cases in practice, if results
for the regression tests are anything to go by.
setrefs.c also contains logic to discard no-op Append and MergeAppend
nodes. We did have knowledge of that behavior at costing time, but
somebody failed to update it when a check on parallel-awareness was
added to the setrefs.c logic. Fix that while we're here.
These changes result in two minor changes in query plans shown in
our regression tests. Neither is relevant to the purposes of its
test case AFAICT.
Patch by me; thanks to Richard Guo for review.
Discussion: https://postgr.es/m/2581077.1651703520@sss.pgh.pa.us
Because they are not available we've used _fileno(stdin) in some places, but
that doesn't reliably work, because stdin might be closed. This is the
prerequisite of the subsequent commit, fixing a failure introduced in
76e38b37a5.
Author: Andres Freund <andres@anarazel.de>
Reported-By: Sandeep Thakkar <sandeep.thakkar@enterprisedb.com>
Message-Id: 20220520164558.ozb7lm6unakqzezi@alap3.anarazel.de (on pgsql-packagers)
Backpatch: 15-, where 76e38b37a5 came in
Thomas Munro
John Naylor
Michael Paquier
Tom Lane
David Rowley
Amit Kapila
Robert Haas
Alexander Korotkov
Andrew Dunstan
Dean Rasheed
Peter Eisentraut
Andres Freund