psql offered USING, WHERE, and SET in this context, but SET is not a valid
possibility here. Seems to have been a thinko in commit f5ab0a14ea
which added DELETE's USING option.
Turns out we must set rl_basic_word_break_characters *before* we call
rl_initialize() the first time, because it will quietly copy that value
elsewhere --- but only on the first call. (Love these undocumented
dependencies.) I broke this yesterday in commit 2ec477dc8108339d;
like that commit, back-patch to all active branches. Per report from
Pavel Stehule.
It emerges that libreadline doesn't notice terminal window size change
events unless they occur while collecting input. This is easy to stumble
over if you resize the window while using a pager to look at query output,
but it can be demonstrated without any pager involvement. The symptom is
that queries exceeding one line are misdisplayed during subsequent input
cycles, because libreadline has the wrong idea of the screen dimensions.
The safest, simplest way to fix this is to call rl_reset_screen_size()
just before calling readline(). That causes an extra ioctl(TIOCGWINSZ)
for every command; but since it only happens when reading from a tty, the
performance impact should be negligible. A more valid objection is that
this still leaves a tiny window during entry to readline() wherein delivery
of SIGWINCH will be missed; but the practical consequences of that are
probably negligible. In any case, there doesn't seem to be any good way to
avoid the race, since readline exposes no functions that seem safe to call
from a generic signal handler --- rl_reset_screen_size() certainly isn't.
It turns out that we also need an explicit rl_initialize() call, else
rl_reset_screen_size() dumps core when called before the first readline()
call.
rl_reset_screen_size() is not present in old versions of libreadline,
so we need a configure test for that. (rl_initialize() is present at
least back to readline 4.0, so we won't bother with a test for it.)
We would need a configure test anyway since libedit's emulation of
libreadline doesn't currently include such a function. Fortunately,
libedit seems not to have any corresponding bug.
Merlin Moncure, adjusted a bit by me
PQhost() can return NULL in non-error situations, namely when a Unix-socket
connection has been selected by default. That behavior is a tad debatable
perhaps, but for the moment we should make sure that psql copes with it.
Unfortunately, do_connect() failed to: it could pass a NULL pointer to
strcmp(), resulting in crashes on most platforms. This was reported as a
security issue by ChenQin of Topsec Security Team, but the consensus of
the security list is that it's just a garden-variety bug with no security
implications.
For paranoia's sake, I made the keep_password test not trust PQuser or
PQport either, even though I believe those will never return NULL given
a valid PGconn.
Back-patch to all supported branches.
The POSIX standard for tar headers requires archive member sizes to be
printed in octal with at most 11 digits, limiting the representable file
size to 8GB. However, GNU tar and apparently most other modern tars
support a convention in which oversized values can be stored in base-256,
allowing any practical file to be a tar member. Adopt this convention
to remove two limitations:
* pg_dump with -Ft output format failed if the contents of any one table
exceeded 8GB.
* pg_basebackup failed if the data directory contained any file exceeding
8GB. (This would be a fatal problem for installations configured with a
table segment size of 8GB or more, and it has also been seen to fail when
large core dump files exist in the data directory.)
File sizes under 8GB are still printed in octal, so that no compatibility
issues are created except in cases that would have failed entirely before.
In addition, this patch fixes several bugs in the same area:
* In 9.3 and later, we'd defined tarCreateHeader's file-size argument as
size_t, which meant that on 32-bit machines it would write a corrupt tar
header for file sizes between 4GB and 8GB, even though no error was raised.
This broke both "pg_dump -Ft" and pg_basebackup for such cases.
* pg_restore from a tar archive would fail on tables of size between 4GB
and 8GB, on machines where either "size_t" or "unsigned long" is 32 bits.
This happened even with an archive file not affected by the previous bug.
* pg_basebackup would fail if there were files of size between 4GB and 8GB,
even on 64-bit machines.
* In 9.3 and later, "pg_basebackup -Ft" failed entirely, for any file size,
on 64-bit big-endian machines.
In view of these potential data-loss bugs, back-patch to all supported
branches, even though removal of the documented 8GB limit might otherwise
be considered a new feature rather than a bug fix.
At least OpenBSD, NetBSD, and Windows don't support it. This repairs
pg_ctl for listen_addresses='0.0.0.0' and listen_addresses='::'. Since
pg_ctl prefers to test a Unix-domain socket, Windows users are most
likely to need this change. Back-patch to 9.1 (all supported versions).
This could change pg_ctl interaction with loopback-interface firewall
rules. Therefore, in 9.4 and earlier (released branches), activate the
change only on known-affected platforms.
Reported (bug #13611) and designed by Kondo Yuta.
pg_ctl start with -w previously relied on a heuristic that the postmaster
would surely always manage to create postmaster.pid within five seconds.
Unfortunately, that fails much more often than we would like on some of the
slower, more heavily loaded buildfarm members.
We have known for quite some time that we could remove the need for that
heuristic on Unix by using fork/exec instead of system() to launch the
postmaster. This allows us to know the exact PID of the postmaster, which
allows near-certain verification that the postmaster.pid file is the one
we want and not a leftover, and it also lets us use waitpid() to detect
reliably whether the child postmaster has exited or not.
What was blocking this change was not wanting to rewrite the Windows
version of start_postmaster() to avoid use of CMD.EXE. That's doable
in theory but would require fooling about with stdout/stderr redirection,
and getting the handling of quote-containing postmaster switches to
stay the same might be rather ticklish. However, we realized that
we don't have to do that to fix the problem, because we can test
whether the shell process has exited as a proxy for whether the
postmaster is still alive. That doesn't allow an exact check of the
PID in postmaster.pid, but we're no worse off than before in that
respect; and we do get to get rid of the heuristic about how long the
postmaster might take to create postmaster.pid.
On Unix, this change means that a second "pg_ctl start -w" immediately
after another such command will now reliably fail, whereas previously
it would succeed if done within two seconds of the earlier command.
Since that's a saner behavior anyway, it's fine. On Windows, the case can
still succeed within the same time window, since pg_ctl can't tell that the
earlier postmaster's postmaster.pid isn't the pidfile it is looking for.
To ensure stable test results on Windows, we can insert a short sleep into
the test script for pg_ctl, ensuring that the existing pidfile looks stale.
This hack can be removed if we ever do rewrite start_postmaster(), but that
no longer seems like a high-priority thing to do.
Back-patch to all supported versions, both because the current behavior
is buggy and because we must do that if we want the buildfarm failures
to go away.
Tom Lane and Michael Paquier
This case seems to have been overlooked when unvalidated check constraints
were introduced, in 9.2. The code would attempt to dump such constraints
over again for each child table, even though adding them to the parent
table is sufficient.
In 9.2 and 9.3, also fix contrib/pg_upgrade/Makefile so that the "make
clean" target fully cleans up after a failed test. This evidently got
dealt with at some point in 9.4, but it wasn't back-patched. I ran into
it while testing this fix ...
Per bug #13656 from Ingmar Brouns.
(Third time's the charm, I hope.)
Additional testing disclosed that this code could mangle already-localized
output from the "money" datatype. We can't very easily skip applying it
to "money" values, because the logic is tied to column right-justification
and people expect "money" output to be right-justified. Short of
decoupling that, we can fix it in what should be a safe enough way by
testing to make sure the string doesn't contain any characters that would
not be expected in plain numeric output.
On closer inspection, those seemingly redundant atoi() calls were not so
much inefficient as just plain wrong: the author of this code either had
not read, or had not understood, the POSIX specification for localeconv().
The grouping field is *not* a textual digit string but separate integers
encoded as chars.
We'll follow the existing code as well as the backend's cash.c in only
honoring the first group width, but let's at least honor it correctly.
This doesn't actually result in any behavioral change in any of the
locales I have installed on my Linux box, which may explain why nobody's
complained; grouping width 3 is close enough to universal that it's barely
worth considering other cases. Still, wrong is wrong, so back-patch.
This code did the wrong thing entirely for numbers with an exponent
but no decimal point (e.g., '1e6'), as reported by Jeff Janes in
bug #13636. More generally, it made lots of unverified assumptions
about what the input string could possibly look like. Rearrange so
that it only fools with leading digits that it's directly verified
are there, and an immediately adjacent decimal point. While at it,
get rid of some useless inefficiencies, like converting the grouping
count string to integer over and over (and over).
This has been broken for a long time, so back-patch to all supported
branches.
Modify pg_dump to restore postgres/template1 databases to non-default
tablespaces by switching out of the database to be moved, then switching
back.
Also, to fix potentially cases where the old/new tablespaces might not
match, fix pg_upgrade to process new/old tablespaces separately in all
cases.
Report by Marti Raudsepp
Patch by Marti Raudsepp, me
Backpatch through 9.0
pg_dump produced fairly silly GRANT/REVOKE commands when dumping types from
pre-9.2 servers, and when dumping functions or procedural languages from
pre-7.3 servers. Those server versions lack the typacl, proacl, and/or
lanacl columns respectively, and pg_dump substituted default values that
were in fact incorrect. We ended up revoking all the owner's own
privileges for the object while granting all privileges to PUBLIC.
Of course the owner would then have those privileges again via PUBLIC, so
long as she did not try to revoke PUBLIC's privileges; which may explain
the lack of field reports. Nonetheless this is pretty silly behavior.
The stakes were raised by my recent patch to make pg_dump dump shell types,
because 9.2 and up pg_dump would proceed to emit bogus GRANT/REVOKE
commands for a shell type if dumping from a pre-9.2 server; and the server
will not accept GRANT/REVOKE commands for a shell type. (Perhaps it
should, but that's a topic for another day.) So the resulting dump script
wouldn't load without errors.
The right thing to do is to act as though these objects have default
privileges (null ACL entries), which causes pg_dump to print no
GRANT/REVOKE commands at all for them. That fixes the silly results
and also dodges the problem with shell types.
In passing, modify getProcLangs() to be less creatively different about
how to handle missing columns when dumping from older server versions.
Every other data-acquisition function in pg_dump does that by substituting
appropriate default values in the version-specific SQL commands, and I see
no reason why this one should march to its own drummer. Its use of
"SELECT *" was likewise not conformant with anyplace else, not to mention
it's not considered good SQL style for production queries.
Back-patch to all supported versions. Although 9.0 and 9.1 pg_dump don't
have the issue with typacl, they are more likely than newer versions to be
used to dump from ancient servers, so we ought to fix the proacl/lanacl
issues all the way back.
Per discussion, it really ought to do this. The original choice to
exclude shell types was probably made in the dark ages before we made
it harder to accidentally create shell types; but that was in 7.3.
Also, cause the standard regression tests to leave a shell type behind,
for convenience in testing the case in pg_dump and pg_upgrade.
Back-patch to all supported branches.
This was broken by commit 0e7e355f27 and
friends, which ignored the fact that gzopen() will treat "-1" in the
mode argument as an invalid character, which it ignores, and a flag for
compression level 1. Now, when this value is encountered no compression
level flag is passed to gzopen, leaving it to use the zlib default.
Also, enforce the documented allowed range for pg_dump's -Z option,
namely 0 .. 9, and remove some consequently dead code from
pg_backup_tar.c.
Problem reported by Marc Mamin.
Backpatch to 9.1, like the patch that introduced the bug.
Per Coverity (not that any of these are so non-obvious that they should not
have been caught before commit). The extent of leakage is probably minor
to unnoticeable, but a leak is a leak. Back-patch as necessary.
Michael Paquier
The psql crash happened when no current connection existed. (The second
new check is optional given today's undocumented NULL argument handling
in PQhost() etc.) Back-patch to 9.0 (all supported versions).
The Service Control Manager should be notified regularly during a shutdown
that takes a long time. Previously we would increaes the counter, but forgot
to actually send the notification to the system. The loop counter was also
incorrectly initalized in the event that the startup of the system took long
enough for it to increase, which could cause the shutdown process not to wait
as long as expected.
Krystian Bigaj, reviewed by Michael Paquier
While gcc doesn't complain if you declare a function "static" and then
define it not-static, other compilers do; and in any case the code is
highly misleading this way. Add the missing "static" keywords to a
couple of recent patches. Per buildfarm member pademelon.
psql was already accepting conninfo strings as the first parameter in
\connect, but the way it worked wasn't sane; some of the other
parameters would get the previous connection's values, causing it to
connect to a completely unexpected server or, more likely, not finding
any server at all because of completely wrong combinations of
parameters.
Fix by explicitely checking for a conninfo-looking parameter in the
dbname position; if one is found, use its complete specification rather
than mix with the other arguments. Also, change tab-completion to not
try to complete conninfo/URI-looking "dbnames" and document that
conninfos are accepted as first argument.
There was a weak consensus to backpatch this, because while the behavior
of using the dbname as a conninfo is nowhere documented for \connect, it
is reasonable to expect that it works because it does work in many other
contexts. Therefore this is backpatched all the way back to 9.0.
To implement this, routines previously private to libpq have been
duplicated so that psql can decide what looks like a conninfo/URI
string. In back branches, just duplicate the same code all the way back
to 9.2, where URIs where introduced; 9.0 and 9.1 have a simpler version.
In master, the routines are moved to src/common and renamed.
Author: David Fetter, Andrew Dunstan. Some editorialization by me
(probably earning a Gierth's "Sloppy" badge in the process.)
Reviewers: Andrew Gierth, Erik Rijkers, Pavel Stěhule, Stephen Frost,
Robert Haas, Andrew Dunstan.
As with initdb these programs need to run with a restricted token, and
if they don't pg_upgrade will fail when run as a user with Adminstrator
privileges.
Backpatch to all live branches. On the development branch the code is
reorganized so that the restricted token code is now in a single
location. On the stable bramches a less invasive change is made by
simply copying the relevant code to pg_upgrade.c and pg_resetxlog.c.
Patches and bug report from Muhammad Asif Naeem, reviewed by Michael
Paquier, slightly edited by me.
GNU readline defines the return value of write_history() as "zero if OK,
else an errno code". libedit's version of that function used to have a
different definition (to wit, "-1 if error, else the number of lines
written to the file"). We tried to work around that by checking whether
errno had become nonzero, but this method has never been kosher according
to the published API of either library. It's reportedly completely broken
in recent Ubuntu releases: psql bleats about "No such file or directory"
when saving ~/.psql_history, even though the write worked fine.
However, libedit has been following the readline definition since somewhere
around 2006, so it seems all right to finally break compatibility with
ancient libedit releases and trust that the return value is what readline
specifies. (I'm not sure when the various Linux distributions incorporated
this fix, but I did find that OS X has been shipping fixed versions since
10.5/Leopard.)
If anyone is still using such an ancient libedit, they will find that psql
complains it can't write ~/.psql_history at exit, even when the file was
written correctly. This is no worse than the behavior we're fixing for
current releases.
Back-patch to all supported branches.
Since 9.1, we've provided extensions with a way to denote
"configuration" tables- tables created by an extension which the user
may modify. By marking these as "configuration" tables, the extension
is asking for the data in these tables to be pg_dump'd (tables which
are not marked in this way are assumed to be entirely handled during
CREATE EXTENSION and are not included at all in a pg_dump).
Unfortunately, pg_dump neglected to consider foreign key relationships
between extension configuration tables and therefore could end up
trying to reload the data in an order which would cause FK violations.
This patch teaches pg_dump about these dependencies, so that the data
dumped out is done so in the best order possible. Note that there's no
way to handle circular dependencies, but those have yet to be seen in
the wild.
The release notes for this should include a caution to users that
existing pg_dump-based backups may be invalid due to this issue. The
data is all there, but restoring from it will require extracting the
data for the configuration tables and then loading them in the correct
order by hand.
Discussed initially back in bug #6738, more recently brought up by
Gilles Darold, who provided an initial patch which was further reworked
by Michael Paquier. Further modifications and documentation updates
by me.
Back-patch to 9.1 where we added the concept of extension configuration
tables.
cfopen() and cfopen_write() failed to pass the compression level through
to zlib, so that you always got the default compression level if you got
any at all.
In passing, also fix these and related functions so that the correct errno
is reliably returned on failure; the original coding supposes that free()
cannot change errno, which is untrue on at least some platforms.
Per bug #12779 from Christoph Berg. Back-patch to 9.1 where the faulty
code was introduced.
Michael Paquier
I bungled resolving a conflict while backpatching 2c0a48589 to 9.2, by
passing mark_done = true to ReceiveXlogStream in pg_receivexlog.c (all
the other branches are ok). Since pg_receivexlog doesn't use a archive
directory that causes 'could not create archive status file "...": No
such file or directory' errors.
Until 9.2.11 is released this can be worked around by creating
'archive_directory' in pg_receivexlog's target directory.
Found by Sergey Konoplev.
pg_database.datfrozenxid and pg_database.datminmxid were not preserved
for the 'postgres' and 'template1' databases. This could cause missing
clog file errors on access to user tables and indexes after upgrades in
these databases.
Backpatch through 9.0
We already had one go at this issue in commit d73b7f973d, but we
failed to notice that buildACLCommands also leaked several PQExpBuffers
along with a simply malloc'd string. This time let's try to make the
fix a bit more future-proof by eliminating the separate exit path.
It's still not exactly critical because pg_dump will curl up and die on
failure; but since the amount of the potential leak is now several KB,
it seems worth back-patching as far as 9.2 where the previous fix landed.
Per Coverity, which evidently is smarter than clang's static analyzer.
Back in 2003 we had a discussion about how to decide which casts to dump.
At the time pg_dump really only considered an object's containing schema
to decide what to dump (ie, dump whatever's not in pg_catalog), and so
we chose a complicated idea involving whether the underlying types were to
be dumped (cf commit a6790ce857). But users
are allowed to create casts between built-in types, and we failed to dump
such casts. Let's get rid of that heuristic, which has accreted even more
ugliness since then, in favor of just looking at the cast's OID to decide
if it's a built-in cast or not.
In passing, also fix some really ancient code that supposed that it had to
manufacture a dependency for the cast on its cast function; that's only
true when dumping from a pre-7.3 server. This just resulted in some wasted
cycles and duplicate dependency-list entries with newer servers, but we
might as well improve it.
Per gripes from a number of people, most recently Greg Sabino Mullane.
Back-patch to all supported branches.
pg_dump.c:dumDatabase() called ArchiveEntry() with the results of a a
query that was PQclear()ed a couple lines earlier.
Backpatch to 9.2 where security labels for shared objects where
introduced.
As every error in mark_file_as_archived() will lead to a failure of
pg_basebackup the FD leak couldn't ever lead to a real problem. It
seems better to fix the leak anyway though, rather than silence
Coverity, as the usage of the function might get extended or copied at
some point in the future.
Pointed out by Coverity.
Backpatch to 9.2, like the relevant part of the previous patch.
WAL (and timeline history) files created by pg_basebackup did not
maintain the new base backup's archive status. That's currently not a
problem if the new node is used as a standby - but if that node is
promoted all still existing files can get archived again. With a high
wal_keep_segment settings that can happen a significant time later -
which is quite confusing.
Change both the backend (for the -x/-X fetch case) and pg_basebackup
(for -X stream) itself to always mark WAL/timeline files included in
the base backup as .done. That's in line with walreceiver.c doing so.
The verbosity of the pg_basebackup changes show pretty clearly that it
needs some refactoring, but that'd result in not be backpatchable
changes.
Backpatch to 9.1 where pg_basebackup was introduced.
Discussion: 20141205002854.GE21964@awork2.anarazel.de
For simple boolean variables such as ON_ERROR_STOP, psql has for a long
time recognized variant spellings of "on" and "off" (such as "1"/"0"),
and it also made a point of warning you if you'd misspelled the setting.
But these conveniences did not exist for other keyword-valued variables.
In particular, though ECHO_HIDDEN and ON_ERROR_ROLLBACK include "on" and
"off" as possible values, none of the alternative spellings for those were
recognized; and to make matters worse the code would just silently assume
"on" was meant for any unrecognized spelling. Several people have reported
getting bitten by this, so let's fix it. In detail, this patch:
* Allows all spellings recognized by ParseVariableBool() for ECHO_HIDDEN
and ON_ERROR_ROLLBACK.
* Reports a warning for unrecognized values for COMP_KEYWORD_CASE, ECHO,
ECHO_HIDDEN, HISTCONTROL, ON_ERROR_ROLLBACK, and VERBOSITY.
* Recognizes all values for all these variables case-insensitively;
previously there was a mishmash of case-sensitive and case-insensitive
behaviors.
Back-patch to all supported branches. There is a small risk of breaking
existing scripts that were accidentally failing to malfunction; but the
consensus is that the chance of detecting real problems and preventing
future mistakes outweighs this.
Used to say just "could not read password from file "...": Success", which
isn't very informative.
Mats Erik Andersson. Backpatch to all supported versions.
Fix breakage induced by commits d8d3d2a4f3
and 463f2625a5: pg_dumpall has crashed when
attempting to dump from pre-8.1 servers since then, due to faulty
construction of the query used for dumping roles from older servers.
The query was erroneous as of the earlier commit, but it wasn't exposed
unless you tried to use --binary-upgrade, which you presumably wouldn't
with a pre-8.1 server. However commit 463f2625a made it fail always.
In HEAD, also fix additional breakage induced in the same query by
commit 491c029dbc, which evidently wasn't
tested against pre-8.1 servers either.
The bug is only latent in 9.1 because 463f2625a hadn't landed yet, but
it seems best to back-patch all branches containing the faulty query.
Gilles Darold
This reverts nearly all of commit 28f6cab61a
in favor of just using the typrelid we already have in pg_dump's TypeInfo
struct for the composite type. As coded, it'd crash if the composite type
had no attributes, since then the query would return no rows.
Back-patch to all supported versions. It seems to not really be a problem
in 9.0 because that version rejects the syntax "create type t as ()", but
we might as well keep the logic similar in all affected branches.
Report and fix by Rushabh Lathia.
Without this fix, parallel restore of a schema-only dump can deadlock,
because when the dump is schema-only, the dependency will still be
pointing at the TABLE item rather than the TABLE DATA item.
Robert Haas and Tom Lane
In psql, expanded mode was not being displayed correctly when using
the normal ascii or unicode linestyles and border set to '3'. Now,
per the documentation, border '3' is really only sensible for HTML
and LaTeX formats, however, that's no excuse for ascii/unicode to
break in that case, and provisions had been made for psql to cleanly
handle this case (and it did, in non-expanded mode).
This was broken when ascii/unicode was initially added a good five
years ago because print_aligned_vertical_line wasn't passed in the
border setting being used by print_aligned_vertical but instead was
given the whole printTableContent. There really isn't a good reason
for vertical_line to have the entire printTableContent structure, so
just pass in the printTextFormat and border setting (similar to how
this is handled in horizontal_line).
Pointed out by Pavel Stehule, fix by me.
Back-patch to all currently-supported versions.
psql's \s (print command history) doesn't work at all with recent libedit
versions when printing to the terminal, because libedit tries to do an
fchmod() on the target file which will fail if the target is /dev/tty.
(We'd already noted this in the context of the target being /dev/null.)
Even before that, it didn't work pleasantly, because libedit likes to
encode the command history file (to ensure successful reloading), which
renders it nigh unreadable, not to mention significantly different-looking
depending on exactly which libedit version you have. So let's forget using
write_history() for this purpose, and instead print the data ourselves,
using logic similar to that used to iterate over the history for newline
encoding/decoding purposes.
While we're at it, insert the ability to use the pager when \s is printing
to the terminal. This has been an acknowledged shortcoming of \s for many
years, so while you could argue it's not exactly a back-patchable bug fix
it still seems like a good improvement. Anyone who's seriously annoyed
at this can use "\s /dev/tty" or local equivalent to get the old behavior.
Experimentation with this showed that the history iteration logic was
actually rather broken when used with libedit. It turns out that with
libedit you have to use previous_history() not next_history() to advance
to more recent history entries. The easiest and most robust fix for this
seems to be to make a run-time test to verify which function to call.
We had not noticed this because libedit doesn't really need the newline
encoding logic: its own encoding ensures that command entries containing
newlines are reloaded correctly (unlike libreadline). So the effective
behavior with recent libedits was that only the oldest history entry got
newline-encoded or newline-decoded. However, because of yet other bugs in
history_set_pos(), some old versions of libedit allowed the existing loop
logic to reach entries besides the oldest, which means there may be libedit
~/.psql_history files out there containing encoded newlines in more than
just the oldest entry. To ensure we can reload such files, it seems
appropriate to back-patch this fix, even though that will result in some
incompatibility with older psql versions (ie, multiline history entries
written by a psql with this fix will look corrupted to a psql without it,
if its libedit is reasonably up to date).
Stepan Rutz and Tom Lane
findDependencyLoops() was not bright about cases where there are multiple
dependency paths between the same two dumpable objects. In most scenarios
this did not hurt us too badly; but since the introduction of section
boundary pseudo-objects in commit a1ef01fe16,
it was possible for this code to take unreasonable amounts of time (tens
of seconds on a database with a couple thousand objects), as reported in
bug #11033 from Joe Van Dyk. Joe's particular problem scenario involved
"pg_dump -a" mode with long chains of foreign key constraints, but I think
that similar problems could arise with other situations as long as there
were enough objects. To fix, add a flag array that lets us notice when we
arrive at the same object again while searching from a given start object.
This simple change seems to be enough to eliminate the performance problem.
Back-patch to 9.1, like the patch that introduced section boundary objects.
Prior to 9.0, pg_dump handled comments on large objects by dumping a bunch
of COMMENT commands into a single BLOB COMMENTS archive object. With
sufficiently many such comments, some of the commands would likely get
split across bufferloads when restoring, causing failures in
direct-to-database restores (though no problem would be evident in text
output). This is the same type of issue we have with table data dumped as
INSERT commands, and it can be fixed in the same way, by using a mini SQL
lexer to figure out where the command boundaries are. Fortunately, the
COMMENT commands are no more complex to lex than INSERTs, so we can just
re-use the existing lexer for INSERTs.
Per bug #10611 from Jacek Zalewski. Back-patch to all active branches.
