Errors (for example I/O errors or disk full) while printing out result
tables were completely ignored, which could result in silently
truncated output in scripts, for example. Fix by adding some basic
error checking and reporting.
Author: Daniel Verite <daniel@manitou-mail.org>
Author: David Zhang <david.zhang@highgo.ca>
Discussion: https://www.postgresql.org/message-id/flat/9a0b3c8d-ee14-4b1d-9d0a-2c993bdabacc@manitou-mail.org
This patch fixes the error message in get_major_server_version() to be
"could not parse version file", and uses the full file path name, rather
than just the data directory path.
Also, commit 4109bb5de4 added the cause of the failure to the "could
not open" error message, and improved quoting. This patch backpatches
the "could not open" cause to PG 12, where it was first widely used, and
backpatches the quoting fix in that patch to all supported releases.
Reported-by: Tom Lane
Discussion: https://postgr.es/m/87pne2w98h.fsf@wibble.ilmari.org
Author: Dagfinn Ilmari Mannsåker
Backpatch-through: 9.5
This commit changes pg_basebackup so that it specifies PROGRESS option in
BASE_BACKUP replication command whether --progress is specified or not.
This causes the server to estimate the total backup size and report it in
pg_stat_progress_basebackup.backup_total, by default. This is reasonable
default because the time required for the estimation would not be so large
in most cases.
Also this commit adds new option --no-estimate-size to pg_basebackup.
This option prevents the server from the estimation, and so is useful to
avoid such estimation time if it's too long.
Author: Fujii Masao
Reviewed-by: Magnus Hagander, Amit Langote
Discussion: https://postgr.es/m/CABUevEyDPPSjP7KRvfTXPdqOdY5aWNkqsB5aAXs3bco5ZwtGHg@mail.gmail.com
Introduce a GUC and a tablespace option to control I/O prefetching, much
like effective_io_concurrency, but for work that is done on behalf of
many client sessions.
Use the new setting in heapam.c instead of the hard-coded formula
effective_io_concurrency + 10 introduced by commit 558a9165e0. Go with
a default value of 10 for now, because it's a round number pretty close
to the value used for that existing case.
Discussion: https://postgr.es/m/CA%2BhUKGJUw08dPs_3EUcdO6M90GnjofPYrWp4YSLaBkgYwS-AqA%40mail.gmail.com
pg_dump is oblivious to this kind of dependency, so they're lost on
dump/restores (and pg_upgrade). Have pg_dump emit ALTER lines so that
they're preserved. Add some pg_dump tests for the whole thing, also.
Reviewed-by: Tom Lane (offlist)
Reviewed-by: Ibrar Ahmed
Reviewed-by: Ahsan Hadi (who also reviewed commit 899a04f5ed)
Discussion: https://postgr.es/m/20200217225333.GA30974@alvherre.pgsql
When a partitioned table is added to a publication, changes of all of
its partitions (current or future) are published via that publication.
This change only affects which tables a publication considers as its
members. The receiving side still sees the data coming from the
individual leaf partitions. So existing restrictions that partition
hierarchies can only be replicated one-to-one are not changed by this.
Author: Amit Langote <amitlangote09@gmail.com>
Reviewed-by: Rafia Sabih <rafia.pghackers@gmail.com>
Reviewed-by: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/CA+HiwqH=Y85vRK3mOdjEkqFK+E=ST=eQiHdpj43L=_eJMOOznQ@mail.gmail.com
Previously, event triggers were restored just after regular triggers
(and FK constraints, which are basically triggers). This is risky
since an event trigger, once installed, could interfere with subsequent
restore commands. Worse, because event triggers don't have any
particular dependencies on any post-data objects, a parallel restore
would consider them eligible to be restored the moment the post-data
phase starts, allowing them to also interfere with restoration of a
whole bunch of objects that would have been restored before them in
a serial restore. There's no way to completely remove the risk of a
misguided event trigger breaking the restore, since if nothing else
it could break other event triggers. But we can certainly push them
to later in the process to minimize the hazard.
To fix, tweak the RestorePass mechanism introduced by commit 3eb9a5e7c
so that event triggers are handled as part of the post-ACL processing
pass (renaming the "REFRESH" pass to "POST_ACL" to reflect its more
general use). This will cause them to restore after everything except
matview refreshes, which seems OK since matview refreshes really ought
to run in the post-restore state of the database. In a parallel
restore, event triggers and matview refreshes might be intermixed,
but that seems all right as well.
Also update the code and comments in pg_dump_sort.c so that its idea
of how things are sorted agrees with what actually happens due to
the RestorePass mechanism. This is mostly cosmetic: it'll affect the
order of objects in a dump's TOC, but not the actual restore order.
But not changing that would be quite confusing to somebody reading
the code.
Back-patch to all supported branches.
Fabrízio de Royes Mello, tweaked a bit by me
Discussion: https://postgr.es/m/CAFcNs+ow1hmFox8P--3GSdtwz-S3Binb6ZmoP6Vk+Xg=K6eZNA@mail.gmail.com
This commit provides psql commands for listing operator classes, operator
families and its contents in psql. New commands will be useful for exploring
capabilities of both builtin opclasses/opfamilies as well as
opclasses/opfamilies defined in extensions.
Discussion: https://postgr.es/m/1529675324.14193.5.camel%40postgrespro.ru
Author: Sergey Cherkashin, Nikita Glukhov, Alexander Korotkov
Reviewed-by: Michael Paquier, Alvaro Herrera, Arthur Zakirov
Reviewed-by: Kyotaro Horiguchi, Andres Freund
Specifically, this patch allows ALTER TYPE to:
* Change the default TOAST strategy for a toastable base type;
* Promote a non-toastable type to toastable;
* Add/remove binary I/O functions for a type;
* Add/remove typmod I/O functions for a type;
* Add/remove a custom ANALYZE statistics functions for a type.
The first of these can be done by the type's owner; all the others
require superuser privilege since misuse could cause problems.
The main motivation for this patch is to allow extensions to
upgrade the feature sets of their data types, so the set of
alterable properties is biased towards that use-case. However
it's also true that changing some other properties would be
a lot harder, as they get baked into physical storage and/or
stored expressions that depend on the type.
Along the way, refactor GenerateTypeDependencies() to make it easier
to call, refactor DefineType's volatility checks so they can be shared
by AlterType, and teach typcache.c that it might have to reload data
from the type's pg_type row, a scenario it never handled before.
Also rearrange alter_type.sgml a bit for clarity (put the
composite-type operations together).
Tomas Vondra and Tom Lane
Discussion: https://postgr.es/m/20200228004440.b23ein4qvmxnlpht@development
A long time ago, it was necessary to declare datatype I/O functions,
triggers, and language handler support functions in a very type-unsafe
way involving a single pseudo-type "opaque". We got rid of those
conventions in 7.3, but there was still support in various places to
automatically convert such functions to the modern declaration style,
to be able to transparently re-load dumps from pre-7.3 servers.
It seems unnecessary to continue to support that anymore, so take out
the hacks; whereupon the "opaque" pseudo-type itself is no longer
needed and can be dropped.
This is part of a group of patches removing various server-side kluges
for transparently upgrading pre-8.0 dump files. Since we've had few
complaints about dropping pg_dump's support for dumping from pre-8.0
servers (commit 64f3524e2), it seems okay to now remove these kluges.
Discussion: https://postgr.es/m/4110.1583255415@sss.pgh.pa.us
Our usual practice for "poor man's enum" catalog columns is to define
macros for the possible values and use those, not literal constants,
in C code. But for some reason lost in the mists of time, this was
never done for typalign/attalign or typstorage/attstorage. It's never
too late to make it better though, so let's do that.
The reason I got interested in this right now is the need to duplicate
some uses of the TYPSTORAGE constants in an upcoming ALTER TYPE patch.
But in general, this sort of change aids greppability and readability,
so it's a good idea even without any specific motivation.
I may have missed a few places that could be converted, and it's even
more likely that pending patches will re-introduce some hard-coded
references. But that's not fatal --- there's no expectation that
we'd actually change any of these values. We can clean up stragglers
over time.
Discussion: https://postgr.es/m/16457.1583189537@sss.pgh.pa.us
OpenBSD falls back to "C" when using an incorrect input with setlocale()
and LC_CTYPE, causing this test, introduced by 008cf04, to fail. This
removes the culprit test to avoid the portability issue.
Per report from Robert Haas, via buildfarm member curculio.
Discussion: https://postgr.es/m/CA+TgmoZ6ddh3mHD9gU8DvNYoFmuJaYYn1+4AvZNp25vTdRwCAQ@mail.gmail.com
Backpatch-through: 11
Attempting to use pg_checksums (pg_verify_checksums in 11) on a data
folder which includes tablespace paths used across multiple major
versions would cause pg_checksums to scan all directories present in
pg_tblspc, and not only marked with TABLESPACE_VERSION_DIRECTORY. This
could lead to failures when for example running sanity checks on an
upgraded instance with --check. Even worse, it was possible to rewrite
on-disk pages with --enable for a cluster potentially online.
This commit makes pg_checksums skip any directories not named
TABLESPACE_VERSION_DIRECTORY, similarly to what is done for base
backups.
Reported-by: Michael Banck
Author: Michael Banck, Bernd Helmle
Discussion: https://postgr.es/m/62031974fd8e941dd8351fbc8c7eff60d59c5338.camel@credativ.de
backpatch-through: 11
The original coding failed to properly quote those arguments, leading to
failures when using quotes in the values used. As the quoting can be
encoding-sensitive, the connection to the backend needs to be taken
before applying the correct quoting.
Author: Michael Paquier
Reviewed-by: Daniel Gustafsson
Discussion: https://postgr.es/m/20200214041004.GB1998@paquier.xyz
Backpatch-through: 9.5
Deduplication reduces the storage overhead of duplicates in indexes that
use the standard nbtree index access method. The deduplication process
is applied lazily, after the point where opportunistic deletion of
LP_DEAD-marked index tuples occurs. Deduplication is only applied at
the point where a leaf page split would otherwise be required. New
posting list tuples are formed by merging together existing duplicate
tuples. The physical representation of the items on an nbtree leaf page
is made more space efficient by deduplication, but the logical contents
of the page are not changed. Even unique indexes make use of
deduplication as a way of controlling bloat from duplicates whose TIDs
point to different versions of the same logical table row.
The lazy approach taken by nbtree has significant advantages over a GIN
style eager approach. Most individual inserts of index tuples have
exactly the same overhead as before. The extra overhead of
deduplication is amortized across insertions, just like the overhead of
page splits. The key space of indexes works in the same way as it has
since commit dd299df8 (the commit that made heap TID a tiebreaker
column).
Testing has shown that nbtree deduplication can generally make indexes
with about 10 or 15 tuples for each distinct key value about 2.5X - 4X
smaller, even with single column integer indexes (e.g., an index on a
referencing column that accompanies a foreign key). The final size of
single column nbtree indexes comes close to the final size of a similar
contrib/btree_gin index, at least in cases where GIN's posting list
compression isn't very effective. This can significantly improve
transaction throughput, and significantly reduce the cost of vacuuming
indexes.
A new index storage parameter (deduplicate_items) controls the use of
deduplication. The default setting is 'on', so all new B-Tree indexes
automatically use deduplication where possible. This decision will be
reviewed at the end of the Postgres 13 beta period.
There is a regression of approximately 2% of transaction throughput with
synthetic workloads that consist of append-only inserts into a table
with several non-unique indexes, where all indexes have few or no
repeated values. The underlying issue is that cycles are wasted on
unsuccessful attempts at deduplicating items in non-unique indexes.
There doesn't seem to be a way around it short of disabling
deduplication entirely. Note that deduplication of items in unique
indexes is fairly well targeted in general, which avoids the problem
there (we can use a special heuristic to trigger deduplication passes in
unique indexes, since we're specifically targeting "version bloat").
Bump XLOG_PAGE_MAGIC because xl_btree_vacuum changed.
No bump in BTREE_VERSION, since the representation of posting list
tuples works in a way that's backwards compatible with version 4 indexes
(i.e. indexes built on PostgreSQL 12). However, users must still
REINDEX a pg_upgrade'd index to use deduplication, regardless of the
Postgres version they've upgraded from. This is the only way to set the
new nbtree metapage flag indicating that deduplication is generally
safe.
Author: Anastasia Lubennikova, Peter Geoghegan
Reviewed-By: Peter Geoghegan, Heikki Linnakangas
Discussion:
https://postgr.es/m/55E4051B.7020209@postgrespro.ruhttps://postgr.es/m/4ab6e2db-bcee-f4cf-0916-3a06e6ccbb55@postgrespro.ru
Invent the concept of a B-Tree equalimage ("equality implies image
equality") support function, registered as support function 4. This
indicates whether it is safe (or not safe) to apply optimizations that
assume that any two datums considered equal by an operator class's order
method must be interchangeable without any loss of semantic information.
This is static information about an operator class and a collation.
Register an equalimage routine for almost all of the existing B-Tree
opclasses. We only need two trivial routines for all of the opclasses
that are included with the core distribution. There is one routine for
opclasses that index non-collatable types (which returns 'true'
unconditionally), plus another routine for collatable types (which
returns 'true' when the collation is a deterministic collation).
This patch is infrastructure for an upcoming patch that adds B-Tree
deduplication.
Author: Peter Geoghegan, Anastasia Lubennikova
Discussion: https://postgr.es/m/CAH2-Wzn3Ee49Gmxb7V1VJ3-AC8fWn-Fr8pfWQebHe8rYRxt5OQ@mail.gmail.com
An instance of PostgreSQL crashing with a bad timing could leave behind
temporary pg_internal.init files, potentially causing failures when
verifying checksums. As the same exclusion lists are used between
pg_rewind, pg_checksums and basebackup.c, all those tools are extended
with prefix checks to keep everything in sync, with dedicated checks
added for pg_internal.init.
Backpatch down to 11, where pg_checksums (pg_verify_checksums in 11) and
checksum verification for base backups have been introduced.
Reported-by: Michael Banck
Author: Michael Paquier
Reviewed-by: Kyotaro Horiguchi, David Steele
Discussion: https://postgr.es/m/62031974fd8e941dd8351fbc8c7eff60d59c5338.camel@credativ.de
Backpatch-through: 11
Windows has this, and so do all other live platforms according to the
buildfarm, so remove the configure probe and src/port/ substitution.
Keep the probe that detects whether _LARGEFILE_SOURCE has to be
defined to get that, though ... that seems to be still relevant in
some places.
This is part of a series of commits to get rid of no-longer-relevant
configure checks and dead src/port/ code. I'm committing them separately
to make it easier to back out individual changes if they prove less
portable than I expect.
Discussion: https://postgr.es/m/15379.1582221614@sss.pgh.pa.us
This fixes and updates a couple of comments related to outdated Windows
versions. Particularly, src/common/exec.c had a fallback implementation
to read a file's line from a pipe because stdin/stdout/stderr does not
exist in Windows 2000 that is removed to simplify src/common/ as there
are unlikely versions of Postgres running on such platforms.
Author: Michael Paquier
Reviewed-by: Kyotaro Horiguchi, Juan José Santamaría Flecha
Discussion: https://postgr.es/m/20191219021526.GC4202@paquier.xyz
This was unaccountably omitted in the original RLS patch.
The SQL syntax is basically the same as for comments on triggers,
so crib code from dumpTrigger().
Per report from Marc Munro. Back-patch to all supported branches.
Discussion: https://postgr.es/m/1581889298.18009.15.camel@bloodnok.com
Commit 0da33c762 introduced an unfortunate regression in pg_ctl on
Windows: if the log file specified with -l doesn't exist yet, and
pg_ctl is running with Administrator privileges, then the log file
might get created with permissions that prevent the postmaster from
writing on it. (It seems that whether this happens depends on whether
the log file is inside the user's home directory or not, and perhaps
on other phase-of-the-moon conditions, which may explain why we failed
to notice it sooner.)
To fix, just don't create the log file if it doesn't exist yet. The
case where we need to wait obviously only occurs with a pre-existing
log file.
In passing, switch from using fopen() to plain open(), saving a few
cycles.
Per bug #16259 from Jonathan Katz and Heath Lord. Back-patch to v12,
as the faulty commit was.
Alexander Lakhin
Discussion: https://postgr.es/m/16259-c5ebed32a262a8b1@postgresql.org
%d can be used to track if the current connection is in a transaction
block or not, and adding it by default to the prompt has the advantage
to not need a modification of .psqlrc, something not possible depending
on the environment.
This discussion has happened across various sources, and there was a
strong consensus in favor of this change.
Author: Vik Fearing
Reviewed-by: Fabien Coelho
Discussion: https://postgr.es/m/09502c40-cfe1-bb29-10f9-4b3fa7b2bbb2@2ndquadrant.com
The previous coding forgot to apply shell quoting to the socket
directory and the data folder, leading to failures when running
pg_upgrade. This refactors the code generating the pg_ctl command
starting clusters to use a more correct shell quoting. Failures are
easier to trigger in 12 and newer versions by using a value of
--socketdir that includes quotes, but it is also possible to cause
failures with quotes included in the default socket directory used by
pg_upgrade or the data folders of the clusters involved in the
upgrade.
As 9.4 is going to be EOL'd with the next minor release, nobody is
likely going to upgrade to it now so this branch is not included in the
set of branches fixed.
Author: Michael Paquier
Reviewed-by: Álvaro Herrera, Noah Misch
Backpatch-through: 9.5
This reverts commit 7bae0ad, as this is not ideal with the tar format,
and we may want to explore more options like what is done by tar with
some equivalents of --owner and --group, but for pg_basebackup.
Per complaints from Magnus Hagander and Stephen Frost.
Discussion: https://postgr.es/m/20200205172259.GW3195@tamriel.snowman.net
First, this code did not bother checking for a failure when calling
dup(). Then, per zlib, gzerror() returns NULL for a NULL input, which
can happen if passing down to gzdopen() an invalid file descriptor or if
there was an allocation failure.
No back-patch is done as this would unlikely be a problem in the field.
Per Coverity.
Reported-by: Tom Lane
Those new assertions can be used at file scope, outside of any function
for compilation checks. This commit provides implementations for C and
C++, and fallback implementations.
Author: Peter Smith
Reviewed-by: Andres Freund, Kyotaro Horiguchi, Dagfinn Ilmari Mannsåker,
Michael Paquier
Discussion: https://postgr.es/m/201DD0641B056142AC8C6645EC1B5F62014B8E8030@SYD1217
Similarly to pg_upgrade, pg_ctl and initdb, a root user is able to use
--version and --help, but cannot execute the actual operation to avoid
the creation of files with permissions incompatible with the
postmaster.
This is a behavior change, so not back-patching is done.
Author: Ian Barwick
Discussion: https://postgr.es/m/CABvVfJVqOdD2neLkYdygdOHvbWz_5K_iWiqY+psMfA=FeAa3qQ@mail.gmail.com
If we failed to fork a worker process, or create a communication pipe
for one, WaitForTerminatingWorkers would suffer an assertion failure
if assert-enabled, otherwise crash or go into an infinite loop. This
was a consequence of not accounting for the startup condition where
we've not yet forked all the workers.
The original bug was that ParallelBackupStart would set workerStatus to
WRKR_IDLE before it had successfully forked a worker. I made things
worse in commit b7b8cc0cf by not understanding the undocumented fact
that the WRKR_TERMINATED state was also meant to represent the case
where a worker hadn't been started yet: I changed enum T_WorkerStatus
so that *all* the worker slots were initially in WRKR_IDLE state. But
this wasn't any more broken in practice, since even one slot in the
wrong state would keep WaitForTerminatingWorkers from terminating.
In v10 and later, introduce an explicit T_WorkerStatus value for
worker-not-started, in hopes of preventing future oversights of the
same ilk. Before that, just document that WRKR_TERMINATED is supposed
to cover that case (partly because it wasn't actively broken, and
partly because the enum is exposed outside parallel.c in those branches,
so there's microscopically more risk involved in changing it).
In all branches, introduce a WORKER_IS_RUNNING status test macro
to hide which T_WorkerStatus values mean that, and be more careful
not to access ParallelSlot fields till we're sure they're valid.
Per report from Vignesh C, though this is my patch not his.
Back-patch to all supported branches.
Discussion: https://postgr.es/m/CALDaNm1Luv-E3sarR+-unz-BjchquHHyfP+YC+2FS2pt_J+wxg@mail.gmail.com
We used to strategically place newlines after some function call left
parentheses to make pgindent move the argument list a few chars to the
left, so that the whole line would fit under 80 chars. However,
pgindent no longer does that, so the newlines just made the code
vertically longer for no reason. Remove those newlines, and reflow some
of those lines for some extra naturality.
Reviewed-by: Michael Paquier, Tom Lane
Discussion: https://postgr.es/m/20200129200401.GA6303@alvherre.pgsql
This patch creates a new extension property, "trusted". An extension
that's marked that way in its control file can be installed by a
non-superuser who has the CREATE privilege on the current database,
even if the extension contains objects that normally would have to be
created by a superuser. The objects within the extension will (by
default) be owned by the bootstrap superuser, but the extension itself
will be owned by the calling user. This allows replicating the old
behavior around trusted procedural languages, without all the
special-case logic in CREATE LANGUAGE. We have, however, chosen to
loosen the rules slightly: formerly, only a database owner could take
advantage of the special case that allowed installation of a trusted
language, but now anyone who has CREATE privilege can do so.
Having done that, we can delete the pg_pltemplate catalog, moving the
knowledge it contained into the extension script files for the various
PLs. This ends up being no change at all for the in-core PLs, but it is
a large step forward for external PLs: they can now have the same ease
of installation as core PLs do. The old "trusted PL" behavior was only
available to PLs that had entries in pg_pltemplate, but now any
extension can be marked trusted if appropriate.
This also removes one of the stumbling blocks for our Python 2 -> 3
migration, since the association of "plpythonu" with Python 2 is no
longer hard-wired into pg_pltemplate's initial contents. Exactly where
we go from here on that front remains to be settled, but one problem
is fixed.
Patch by me, reviewed by Peter Eisentraut, Stephen Frost, and others.
Discussion: https://postgr.es/m/5889.1566415762@sss.pgh.pa.us
Commit 40d964ec99 allowed vacuum command to leverage multiple CPUs by
invoking parallel workers to process indexes. This commit provides a
'--parallel' option to specify the parallel degree used by vacuum command.
Author: Masahiko Sawada, with few modifications by me
Reviewed-by: Mahendra Singh and Amit Kapila
Discussion: https://postgr.es/m/CAD21AoDTPMgzSkV4E3SFo1CH_x50bf5PqZFQf4jmqjk-C03BWg@mail.gmail.com
The signature of XLogReadRecord() required the caller to pass the starting
WAL position as argument, or InvalidXLogRecPtr to continue reading at the
end of previous record. That's slightly awkward to the callers, as most
of them don't want to randomly jump around in the WAL stream, but start
reading at one position and then read everything from that point onwards.
Remove the 'RecPtr' argument and add a new function XLogBeginRead() to
specify the starting position instead. That's more convenient for the
callers. Also, xlogreader holds state that is reset when you change the
starting position, so having a separate function for doing that feels like
a more natural fit.
This changes XLogFindNextRecord() function so that it doesn't reset the
xlogreader's state to what it was before the call anymore. Instead, it
positions the xlogreader to the found record, like XLogBeginRead().
Reviewed-by: Kyotaro Horiguchi, Alvaro Herrera
Discussion: https://www.postgresql.org/message-id/5382a7a3-debe-be31-c860-cb810c08f366%40iki.fi
I had supposed that all versions of Readline that have filename
quoting hooks also have the rl_completion_suppress_quote variable.
But it seems OpenBSD managed to find a version someplace that does
not, so we'll have to expend a separate configure probe for that.
(Light testing suggests that this version also lacks the bugs that
make it necessary to frob that variable. Hooray!)
Per buildfarm.
The Readline library contains a fair amount of knowledge about how to
tab-complete filenames, but it turns out that that doesn't work too well
unless we follow its expectation that we use its filename quoting hooks
to quote and de-quote filenames. We were trying to do such quote handling
within complete_from_files(), and that's still what we have to do if we're
using libedit, which lacks those hooks. But for Readline, it works a lot
better if we tell Readline that single-quote is a quoting character and
then provide hooks that know the details of the quoting rules for SQL
and psql meta-commands.
Hence, resurrect the quoting hook functions that existed in the original
version of tab-complete.c (and were disabled by commit f6689a328 because
they "didn't work so well yet"), and whack on them until they do seem to
work well.
Notably, this fixes bug #16059 from Steven Winfield, who pointed out
that the previous coding would strip quote marks from filenames in SQL
COPY commands, even though they're syntactically necessary there.
Now, we not only don't do that, but we'll add a quote mark when you
tab-complete, even if you didn't type one.
Getting this to work across a range of libedit versions (and, to a
lesser extent, libreadline versions) was depressingly difficult.
It will be interesting to see whether the new regression test cases
pass everywhere in the buildfarm.
Some future patch might try to handle quoted SQL identifiers with
similar explicit quoting/dequoting logic, but that's for another day.
Patch by me, reviewed by Peter Eisentraut.
Discussion: https://postgr.es/m/16059-8836946734c02b84@postgresql.org
