Commit Graph

21478 Commits

Author SHA1 Message Date
Tom Lane 6c20bdb2a2 Further tweak memory management for regex DFAs.
Coverity is still unhappy after commit 190c79884, and after looking
closer I think it might be onto something.  The callers of newdfa()
typically drop out if v->err has been set nonzero, which newdfa()
is faithfully doing if it fails.  However, what if v->err was already
nonzero before we entered newdfa()?  Then newdfa() could succeed and
the caller would promptly leak its result.

I don't think this scenario can actually happen, but the predicate
"v->err is always zero when newdfa() is called" seems difficult to be
entirely sure of; there's a good deal of code that potentially could
get that wrong.

It seems better to adjust the callers to directly check for a null
result instead of relying on ISERR() tests.  This is slightly cheaper
than the previous coding anyway.

Lacking evidence that there's any real bug, no back-patch.
2021-03-08 16:32:29 -05:00
Amit Kapila 8a812e5106 Track replication origin progress for rollbacks.
Commit 1eb6d6527a allowed to track replica origin replay progress for 2PC
but it was not complete. It misses to properly track the progress for
rollback prepared especially it missed updating the code for recovery.
Additionally, we need to allow tracking it on subscriber nodes where
wal_level might not be logical.

It is required to track decoding of 2PC which is committed in PG14
(a271a1b50e) and also nobody complained about this till now so not
backpatching it.

Author: Amit Kapila
Reviewed-by: Michael Paquier and Ajin Cherian
Discussion: https://postgr.es/m/CAA4eK1L-kHmMnSdrRW6UhRbCjR7cgh04c+6psY15qzT6ktcd+g@mail.gmail.com
2021-03-08 07:54:03 +05:30
Heikki Linnakangas 3174d69fb9 Remove server and libpq support for old FE/BE protocol version 2.
Protocol version 3 was introduced in PostgreSQL 7.4. There shouldn't be
many clients or servers left out there without version 3 support. But as
a courtesy, I kept just enough of the old protocol support that we can
still send the "unsupported protocol version" error in v2 format, so that
old clients can display the message properly. Likewise, libpq still
understands v2 ErrorResponse messages when establishing a connection.

The impetus to do this now is that I'm working on a patch to COPY
FROM, to always prefetch some data. We cannot do that safely with the
old protocol, because it requires parsing the input one byte at a time
to detect the end-of-copy marker.

Reviewed-by: Tom Lane, Alvaro Herrera, John Naylor
Discussion: https://www.postgresql.org/message-id/9ec25819-0a8a-d51a-17dc-4150bb3cca3b%40iki.fi
2021-03-04 10:45:55 +02:00
Tom Lane 0a687c8f10 Add trim_array() function.
This has been in the SQL spec since 2008.  It's a pretty thin
wrapper around the array slice functionality, but the spec
says we should have it, so here it is.

Vik Fearing, reviewed by Dian Fay

Discussion: https://postgr.es/m/fc92ce17-9655-8ff1-c62a-4dc4c8ccd815@postgresfriends.org
2021-03-03 16:39:57 -05:00
Peter Eisentraut e527a99055 Some copy-editing of GUC descriptions 2021-03-03 07:14:35 +01:00
Thomas Munro 8eda3eba30 Use sort_template.h for qsort_tuple() and qsort_ssup().
Replace the Perl code previously used to generate specialized sort
functions with sort_template.h.

Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/CA%2BhUKGJ2-eaDqAum5bxhpMNhvuJmRDZxB_Tow0n-gse%2BHG0Yig%40mail.gmail.com
2021-03-03 17:02:32 +13:00
Amit Kapila 19890a064e Add option to enable two_phase commits via pg_create_logical_replication_slot.
Commit 0aa8a01d04 extends the output plugin API to allow decoding of
prepared xacts and allowed the user to enable/disable the two-phase option
via pg_logical_slot_get_changes(). This can lead to a problem such that
the first time when it gets changes via pg_logical_slot_get_changes()
without two_phase option enabled it will not get the prepared even though
prepare is after consistent snapshot. Now next time during getting changes,
if the two_phase option is enabled it can skip prepare because by that
time start decoding point has been moved. So the user will only get commit
prepared.

Allow to enable/disable this option at the create slot time and default
will be false. It will break the existing slots which is fine in a major
release.

Author: Ajin Cherian
Reviewed-by: Amit Kapila and Vignesh C
Discussion: https://postgr.es/m/d0f60d60-133d-bf8d-bd70-47784d8fabf3@enterprisedb.com
2021-03-03 07:34:11 +05:30
Peter Geoghegan 5b2f2af3d9 nbtree page deletion: Add leaftopparent assertion.
Add documenting assertion.  This makes it easier to follow how we
maintain the top parent link in target subtree's half-dead/leaf level
page.
2021-03-02 14:06:07 -08:00
Peter Geoghegan 3d8d5787a3 Fix nbtree page deletion error messages.
Adjust some "can't happen" error messages that assumed that the page
deletion target page must be a half-dead page.  This assumption was
wrong in the case of an internal target page.  Simply refer to these
pages as the target page instead.

Internal pages are never marked half-dead.  There is exactly one
half-dead page for each subtree undergoing deletion.  The half-dead page
is also the target subtree's leaf-level page.  This has been the case
since commit efada2b8, which totally overhauled nbtree page deletion.
2021-03-02 13:02:24 -08:00
Tom Lane d16f8c8e41 Mark default_transaction_read_only as GUC_REPORT.
This allows clients to find out the setting at connection time without
having to expend a query round trip to do so; which is helpful when
trying to identify read/write servers.  (One must also look at
in_hot_standby, but that's already GUC_REPORT, cf bf8a662c9.)
Modifying libpq to make use of this will come soon, but I felt it
cleaner to push the server change separately.

Haribabu Kommi, Greg Nancarrow, Vignesh C; reviewed at various times
by Laurenz Albe, Takayuki Tsunakawa, Peter Smith.

Discussion: https://postgr.es/m/CAF3+xM+8-ztOkaV9gHiJ3wfgENTq97QcjXQt+rbFQ6F7oNzt9A@mail.gmail.com
2021-03-02 13:53:54 -05:00
Tom Lane 4604f83fdf Suppress unnecessary regex subre nodes in a couple more cases.
This extends the changes made in commit cebc1d34e, teaching
parseqatom() to generate fewer or cheaper subre nodes in some edge
cases.  The case of interest here is a quantified atom that is "messy"
only because it has greediness opposite to what preceded it (whereas
captures and backrefs are intrinsically messy).  In this case we don't
need an iteration node, since we don't care where the sub-matches of
the quantifier are; and we might also not need a second concatenation
node.  This seems of only marginal real-world use according to my
testing, but I wanted to get it in before wrapping up this series of
regex performance fixes.

Discussion: https://postgr.es/m/1340281.1613018383@sss.pgh.pa.us
2021-03-02 12:14:14 -05:00
Tom Lane 0c3405cf11 Improve performance of regular expression back-references.
In some cases, at the time that we're doing an NFA-based precheck
of whether a backref subexpression can match at a particular place
in the string, we already know which substring the referenced
subexpression matched.  If so, we might as well forget about the NFA
and just compare the substring; this is faster and it gives an exact
rather than approximate answer.

In general, this optimization can help while we are prechecking within
the second child expression of a concat node, while the capture was
within the first child expression; then the substring was saved during
cdissect() of the first child and will be available to NFA checks done
while cdissect() recurses into the second child.  It can help quite a
lot if the tree looks like

              concat
             /      \
      capture        concat
                    /      \
     expensive stuff        backref

as we will be able to avoid recursively dissecting the "expensive
stuff" before discovering that the backref isn't satisfied with a
particular midpoint that the lower concat node is testing.  This
doesn't help if the concat tree is left-deep, as the capture node
won't get set soon enough (and it's hard to fix that without changing
the engine's match behavior).  Fortunately, right-deep concat trees
are the common case.

Patch by me, reviewed by Joel Jacobson

Discussion: https://postgr.es/m/661609.1614560029@sss.pgh.pa.us
2021-03-02 11:55:12 -05:00
Tom Lane 4aea704a5b Fix semantics of regular expression back-references.
POSIX defines the behavior of back-references thus:

    The back-reference expression '\n' shall match the same (possibly
    empty) string of characters as was matched by a subexpression
    enclosed between "\(" and "\)" preceding the '\n'.

As far as I can see, the back-reference is supposed to consider only
the data characters matched by the referenced subexpression.  However,
because our engine copies the NFA constructed from the referenced
subexpression, it effectively enforces any constraints therein, too.
As an example, '(^.)\1' ought to match 'xx', or any other string
starting with two occurrences of the same character; but in our code
it does not, and indeed can't match anything, because the '^' anchor
constraint is included in the backref's copied NFA.  If POSIX intended
that, you'd think they'd mention it.  Perl for one doesn't act that
way, so it's hard to conclude that this isn't a bug.

Fix by modifying the backref's NFA immediately after it's copied from
the reference, replacing all constraint arcs by EMPTY arcs so that the
constraints are treated as automatically satisfied.  This still allows
us to enforce matching rules that depend only on the data characters;
for example, in '(^\d+).*\1' the NFA matching step will still know
that the backref can only match strings of digits.

Perhaps surprisingly, this change does not affect the results of any
of a rather large corpus of real-world regexes.  Nonetheless, I would
not consider back-patching it, since it's a clear compatibility break.

Patch by me, reviewed by Joel Jacobson

Discussion: https://postgr.es/m/661609.1614560029@sss.pgh.pa.us
2021-03-02 11:34:53 -05:00
Michael Paquier fabde52fab Simplify code to switch pg_class.relrowsecurity in tablecmds.c
The same code pattern was repeated twice to enable or disable ROW LEVEL
SECURITY with an ALTER TABLE command.  This makes the code slightly
cleaner.

Author: Justin Pryzby
Reviewed-by: Zhihong Yu
Discussion: https://postgr.es/m/20210228211854.GC20769@telsasoft.com
2021-03-02 12:30:21 +09:00
Tom Lane ffd3944ab9 Improve reporting for syntax errors in multi-line JSON data.
Point to the specific line where the error was detected; the
previous code tended to include several preceding lines as well.
Avoid re-scanning the entire input to recompute which line that
was.  Simplify the logic a bit.  Add test cases.

Simon Riggs and Hamid Akhtar, reviewed by Daniel Gustafsson and myself

Discussion: https://postgr.es/m/CANbhV-EPBnXm3MF_TTWBwwqgn1a1Ghmep9VHfqmNBQ8BT0f+_g@mail.gmail.com
2021-03-01 16:44:17 -05:00
Thomas Munro bd69ddfcdb Remove obsolete comment for WaitForProcSignalBarrier().
Commit 814f1d8b removed the behavior described.

Reported-by: Amit Kapila <amit.kapila16@gmail.com>
2021-03-02 09:30:57 +13:00
Thomas Munro f5a5773a9d Allow condition variables to be used in interrupt code.
Adjust the condition variable sleep loop to work correctly when code
reached by its internal CHECK_FOR_INTERRUPTS() call interacts with
another condition variable.

There are no such cases currently, but a proposed patch would do this.

Discussion: https://postgr.es/m/CA+hUKGLdemy2gBm80kz20GTe6hNVwoErE8KwcJk6-U56oStjtg@mail.gmail.com
2021-03-01 17:24:47 +13:00
Thomas Munro 814f1d8bc3 Use condition variables for ProcSignalBarriers.
Instead of a poll/sleep loop, use a condition variable for precise
wake-up whenever a backend's pss_barrierGeneration advances.

Discussion: https://postgr.es/m/CA+hUKGLdemy2gBm80kz20GTe6hNVwoErE8KwcJk6-U56oStjtg@mail.gmail.com
2021-03-01 17:23:43 +13:00
Amit Kapila 8bdb1332eb Avoid repeated decoding of prepared transactions after a restart.
In commit a271a1b50e, we allowed decoding at prepare time and the prepare
was decoded again if there is a restart after decoding it. It was done
that way because we can't distinguish between the cases where we have not
decoded the prepare because it was prior to consistent snapshot or we have
decoded it earlier but restarted. To distinguish between these two cases,
we have introduced an initial_consistent_point at the slot level which is
an LSN at which we found a consistent point at the time of slot creation.
This is also the point where we have exported a snapshot for the initial
copy. So, prepare transaction prior to this point are sent along with
commit prepared.

This commit bumps SNAPBUILD_VERSION because of change in SnapBuild. It
will break existing slots which is fine in a major release.

Author: Ajin Cherian, based on idea by Andres Freund
Reviewed-by: Amit Kapila and Vignesh C
Discussion: https://postgr.es/m/d0f60d60-133d-bf8d-bd70-47784d8fabf3@enterprisedb.com
2021-03-01 09:11:18 +05:30
Thomas Munro 6230912f23 Use FeBeWaitSet for walsender.c.
This avoids the need to set up and tear down a fresh WaitEventSet every
time we need need to wait.  We have to add an explicit exit on
postmaster exit (FeBeWaitSet isn't set up to do that automatically), so
move the code to do that into a new function to avoid repetition.

Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> (earlier version)
Discussion: https://postgr.es/m/CA%2BhUKGJAC4Oqao%3DqforhNey20J8CiG2R%3DoBPqvfR0vOJrFysGw%40mail.gmail.com
2021-03-01 16:19:38 +13:00
Thomas Munro a042ba2ba7 Introduce symbolic names for FeBeWaitSet positions.
Previously we used 0 and 1 to refer to the socket and latch in far flung
parts of the tree, without any explanation.  Also use PGINVALID_SOCKET
rather than -1 in a couple of places that didn't already do that.

Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKGJAC4Oqao%3DqforhNey20J8CiG2R%3DoBPqvfR0vOJrFysGw%40mail.gmail.com
2021-03-01 16:10:16 +13:00
Amit Kapila b4e3dc7fd4 Update the docs and comments for decoding of prepared xacts.
Commit a271a1b50e introduced decoding at prepare time in ReorderBuffer.
This can lead to deadlock for out-of-core logical replication solutions
that uses this feature to build distributed 2PC in case such transactions
lock [user] catalog tables exclusively. They need to inform users to not
have locks on catalog tables (via explicit LOCK command) in such
transactions.

Reported-by: Andres Freund
Discussion: https://postgr.es/m/20210222222847.tpnb6eg3yiykzpky@alap3.anarazel.de
2021-03-01 08:14:33 +05:30
Thomas Munro 6148656a0b Use EVFILT_SIGNAL for kqueue latches.
Cut down on system calls and other overheads by waiting for SIGURG
explicitly with kqueue instead of using a signal handler and self-pipe.
Affects *BSD and macOS systems.

This leaves only the poll implementation with a signal handler and the
traditional self-pipe trick.

Discussion: https://postgr.es/m/CA+hUKGJjxPDpzBE0a3hyUywBvaZuC89yx3jK9RFZgfv_KHU7gg@mail.gmail.com
2021-03-01 14:20:04 +13:00
Thomas Munro 6a2a70a020 Use signalfd(2) for epoll latches.
Cut down on system calls and other overheads by reading from a signalfd
instead of using a signal handler and self-pipe.  Affects Linux sytems,
and possibly others including illumos that implement the Linux epoll and
signalfd interfaces.

Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA+hUKGJjxPDpzBE0a3hyUywBvaZuC89yx3jK9RFZgfv_KHU7gg@mail.gmail.com
2021-03-01 14:12:02 +13:00
Thomas Munro 83709a0d5a Use SIGURG rather than SIGUSR1 for latches.
Traditionally, SIGUSR1 has been overloaded for ad-hoc signals,
procsignal.c signals and latch.c wakeups.  Move that last use over to a
new dedicated signal.  SIGURG is normally used to report out-of-band
socket data, but PostgreSQL doesn't use that facility.

The signal handler is now installed in all postmaster children by
InitializeLatchSupport().  Those wishing to disconnect from it should
call ShutdownLatchSupport().

Future patches will use this separation of signals to avoid the need for
a signal handler on some operating systems.

Discussion: https://postgr.es/m/CA+hUKGJjxPDpzBE0a3hyUywBvaZuC89yx3jK9RFZgfv_KHU7gg@mail.gmail.com
2021-03-01 12:44:12 +13:00
Thomas Munro c8f3bc2401 Optimize latches to send fewer signals.
Don't send signals to processes that aren't sleeping.

Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA+hUKGJjxPDpzBE0a3hyUywBvaZuC89yx3jK9RFZgfv_KHU7gg@mail.gmail.com
2021-03-01 12:44:12 +13:00
Thomas Munro d1b90995e8 Remove latch.c workaround for Linux < 2.6.27.
Commit 82ebbeb0 added a workaround for systems with no epoll_create1()
and EPOLL_CLOEXEC.  Linux < 2.6.27 and glibc < 2.9 are long gone.  Now
seems like a good time to drop the extra code, because otherwise we'd
have to add similar already-dead workaround code to new patches using
XXX_CLOEXEC flags that arrived in the same kernel release.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CA%2BhUKGKL_%3DaO%3Dr30N%3Ds9VoDgTqHpRSzePRbA9dkYO7snc7HsxA%40mail.gmail.com
2021-03-01 11:24:28 +13:00
Alvaro Herrera 25936fd46c
Fix use-after-free bug with AfterTriggersTableData.storeslot
AfterTriggerSaveEvent() wrongly allocates the slot in execution-span
memory context, whereas the correct thing is to allocate it in
a transaction-span context, because that's where the enclosing
AfterTriggersTableData instance belongs into.

Backpatch to 12 (the test back to 11, where it works well with no code
changes, and it's good to have to confirm that the case was previously
well supported); this bug seems introduced by commit ff11e7f4b9.

Reported-by: Bertrand Drouvot <bdrouvot@amazon.com>
Author: Amit Langote <amitlangote09@gmail.com>
Discussion: https://postgr.es/m/39a71864-b120-5a5c-8cc5-c632b6f16761@amazon.com
2021-02-27 18:09:15 -03:00
David Rowley 977b2c0853 Add missing TidRangeScan readfunc
Mistakenly forgotten in bb437f995
2021-02-27 23:21:21 +13:00
David Rowley bb437f995d Add TID Range Scans to support efficient scanning ranges of TIDs
This adds a new executor node named TID Range Scan.  The query planner
will generate paths for TID Range scans when quals are discovered on base
relations which search for ranges on the table's ctid column.  These
ranges may be open at either end. For example, WHERE ctid >= '(10,0)';
will return all tuples on page 10 and over.

To support this, two new optional callback functions have been added to
table AM.  scan_set_tidrange is used to set the scan range to just the
given range of TIDs.  scan_getnextslot_tidrange fetches the next tuple
in the given range.

For AMs were scanning ranges of TIDs would not make sense, these functions
can be set to NULL in the TableAmRoutine.  The query planner won't
generate TID Range Scan Paths in that case.

Author: Edmund Horner, David Rowley
Reviewed-by: David Rowley, Tomas Vondra, Tom Lane, Andres Freund, Zhihong Yu
Discussion: https://postgr.es/m/CAMyN-kB-nFTkF=VA_JPwFNo08S0d-Yk0F741S2B7LDmYAi8eyA@mail.gmail.com
2021-02-27 22:59:36 +13:00
Peter Eisentraut f4adc41c4f Enhanced cycle mark values
Per SQL:202x draft, in the CYCLE clause of a recursive query, the
cycle mark values can be of type boolean and can be omitted, in which
case they default to TRUE and FALSE.

Reviewed-by: Vik Fearing <vik@postgresfriends.org>
Discussion: https://www.postgresql.org/message-id/flat/db80ceee-6f97-9b4a-8ee8-3ba0c58e5be2@2ndquadrant.com
2021-02-27 08:13:24 +01:00
Tom Lane 0fc1af174c Improve memory management in regex compiler.
The previous logic here created a separate pool of arcs for each
state, so that the out-arcs of each state were physically stored
within it.  Perhaps this choice was driven by trying to not include
a "from" pointer within each arc; but Spencer gave up on that idea
long ago, and it's hard to see what the value is now.  The approach
turns out to be fairly disastrous in terms of memory consumption,
though.  In the first place, NFAs built by this engine seem to have
about 4 arcs per state on average, with a majority having only one
or two out-arcs.  So pre-allocating 10 out-arcs for each state is
already cause for a factor of two or more bloat.  Worse, the NFA
optimization phase moves arcs around with abandon.  In a large NFA,
some of the states will have hundreds of out-arcs, so towards the
end of the optimization phase we have a significant number of states
whose arc pools have room for hundreds of arcs each, even though only
a few of those arcs are in use.  We have seen real-world regexes in
which this effect bloats the memory requirement by 25X or even more.

Hence, get rid of the per-state arc pools in favor of a single arc
pool for the whole NFA, with variable-sized allocation batches
instead of always asking for 10 at a time.  While we're at it,
let's batch the allocations of state structs too, to further reduce
the malloc traffic.

This incidentally allows moveouts() to be optimized in a similar
way to moveins(): when moving an arc to another state, it's now
valid to just re-link the same arc struct into a different outchain,
where before the code invariants required us to make a physically
new arc and then free the old one.

These changes reduce the regex compiler's typical space consumption
for average-size regexes by about a factor of two, and much more for
large or complicated regexes.  In a large test set of real-world
regexes, we formerly had half a dozen cases that failed with "regular
expression too complex" due to exceeding the REG_MAX_COMPILE_SPACE
limit (about 150MB); we would have had to raise that limit to
something close to 400MB to make them work with the old code.  Now,
none of those cases need more than 13MB to compile.  Furthermore,
the test set is about 10% faster overall due to less malloc traffic.

Discussion: https://postgr.es/m/168861.1614298592@sss.pgh.pa.us
2021-02-26 13:52:10 -05:00
Thomas Munro 8556267b2b Revert "pg_collation_actual_version() -> pg_collation_current_version()."
This reverts commit 9cf184cc05.  Name
change less well received than anticipated.

Discussion: https://postgr.es/m/afcfb97e-88a1-a540-db95-6c573b93bc2b%40eisentraut.org
2021-02-26 15:29:27 +13:00
Tom Lane 80ca8464fe Fix list-manipulation bug in WITH RECURSIVE processing.
makeDependencyGraphWalker and checkWellFormedRecursionWalker
thought they could hold onto a pointer to a list's first
cons cell while the list was modified by recursive calls.
That was okay when the cons cell was actually separately
palloc'd ... but since commit 1cff1b95a, it's quite unsafe,
leading to core dumps or incorrect complaints of faulty
WITH nesting.

In the field this'd require at least a seven-deep WITH nest
to cause an issue, but enabling DEBUG_LIST_MEMORY_USAGE
allows the bug to be seen with lesser nesting depths.

Per bug #16801 from Alexander Lakhin.  Back-patch to v13.

Michael Paquier and Tom Lane

Discussion: https://postgr.es/m/16801-393c7922143eaa4d@postgresql.org
2021-02-25 20:47:32 -05:00
Peter Geoghegan 2376361839 VACUUM VERBOSE: Count "newly deleted" index pages.
Teach VACUUM VERBOSE to report on pages deleted by the _current_ VACUUM
operation -- these are newly deleted pages.  VACUUM VERBOSE continues to
report on the total number of deleted pages in the entire index (no
change there).  The former is a subset of the latter.

The distinction between each category of deleted index page only arises
with index AMs where page deletion is supported and is decoupled from
page recycling for performance reasons.

This is follow-up work to commit e5d8a999, which made nbtree store
64-bit XIDs (not 32-bit XIDs) in pages at the point at which they're
deleted.  Note that the btm_last_cleanup_num_delpages metapage field
added by that commit usually gets set to pages_newly_deleted.  The
exceptions (the scenarios in which they're not equal) all seem to be
tricky cases for the implementation (of page deletion and recycling) in
general.

Author: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-WznpdHvujGUwYZ8sihX%3Dd5u-tRYhi-F4wnV2uN2zHpMUXw%40mail.gmail.com
2021-02-25 14:32:18 -08:00
Tom Lane 301ed8812e Doc: remove src/backend/regex/re_syntax.n.
We aren't publishing this file as documentation, and it's been
much more haphazardly maintained than the real docs in func.sgml,
so let's just drop it.  I think the only reason I included it in
commit 7bcc6d98f was that the Berkeley-era sources had had a man
page in this directory.

Discussion: https://postgr.es/m/4099447.1614186542@sss.pgh.pa.us
2021-02-25 13:33:27 -05:00
Tom Lane 7dc13a0f08 Change regex \D and \W shorthands to always match newlines.
Newline is certainly not a digit, nor a word character, so it is
sensible that it should match these complemented character classes.
Previously, \D and \W acted that way by default, but in
newline-sensitive mode ('n' or 'p' flag) they did not match newlines.

This behavior was previously forced because explicit complemented
character classes don't match newlines in newline-sensitive mode;
but as of the previous commit that implementation constraint no
longer exists.  It seems useful to change this because the primary
real-world use for newline-sensitive mode seems to be to match the
default behavior of other regex engines such as Perl and Javascript
... and their default behavior is that these match newlines.

The old behavior can be kept by writing an explicit complemented
character class, i.e. [^[:digit:]] or [^[:word:]].  (This means
that \D and \W are not exactly equivalent to those strings, but
they weren't anyway.)

Discussion: https://postgr.es/m/3220564.1613859619@sss.pgh.pa.us
2021-02-25 13:29:06 -05:00
Tom Lane 2a0af7fe46 Allow complemented character class escapes within regex brackets.
The complement-class escapes \D, \S, \W are now allowed within
bracket expressions.  There is no semantic difficulty with doing
that, but the rather hokey macro-expansion-based implementation
previously used here couldn't cope.

Also, invent "word" as an allowed character class name, thus "\w"
is now equivalent to "[[:word:]]" outside brackets, or "[:word:]"
within brackets.  POSIX allows such implementation-specific
extensions, and the same name is used in e.g. bash.

One surprising compatibility issue this raises is that constructs
such as "[\w-_]" are now disallowed, as our documentation has always
said they should be: character classes can't be endpoints of a range.
Previously, because \w was just a macro for "[:alnum:]_", such a
construct was read as "[[:alnum:]_-_]", so it was accepted so long as
the character after "-" was numerically greater than or equal to "_".

Some implementation cleanup along the way:

* Remove the lexnest() hack, and in consequence clean up wordchrs()
to not interact with the lexer.

* Fix colorcomplement() to not be O(N^2) in the number of colors
involved.

* Get rid of useless-as-far-as-I-can-see calls of element()
on single-character character element names in brackpart().
element() always maps these to the character itself, and things
would be quite broken if it didn't --- should "[a]" match something
different than "a" does?  Besides, the shortcut path in brackpart()
wasn't doing this anyway, making it even more inconsistent.

Discussion: https://postgr.es/m/2845172.1613674385@sss.pgh.pa.us
Discussion: https://postgr.es/m/3220564.1613859619@sss.pgh.pa.us
2021-02-25 13:00:40 -05:00
Peter Geoghegan e5d8a99903 Use full 64-bit XIDs in deleted nbtree pages.
Otherwise we risk "leaking" deleted pages by making them non-recyclable
indefinitely.  Commit 6655a729 did the same thing for deleted pages in
GiST indexes.  That work was used as a starting point here.

Stop storing an XID indicating the oldest bpto.xact across all deleted
though unrecycled pages in nbtree metapages.  There is no longer any
reason to care about that condition/the oldest XID.  It only ever made
sense when wraparound was something _bt_vacuum_needs_cleanup() had to
consider.

The btm_oldest_btpo_xact metapage field has been repurposed and renamed.
It is now btm_last_cleanup_num_delpages, which is used to remember how
many non-recycled deleted pages remain from the last VACUUM (in practice
its value is usually the precise number of pages that were _newly
deleted_ during the specific VACUUM operation that last set the field).

The general idea behind storing btm_last_cleanup_num_delpages is to use
it to give _some_ consideration to non-recycled deleted pages inside
_bt_vacuum_needs_cleanup() -- though never too much.  We only really
need to avoid leaving a truly excessive number of deleted pages in an
unrecycled state forever.  We only do this to cover certain narrow cases
where no other factor makes VACUUM do a full scan, and yet the index
continues to grow (and so actually misses out on recycling existing
deleted pages).

These metapage changes result in a clear user-visible benefit: We no
longer trigger full index scans during VACUUM operations solely due to
the presence of only 1 or 2 known deleted (though unrecycled) blocks
from a very large index.  All that matters now is keeping the costs and
benefits in balance over time.

Fix an issue that has been around since commit 857f9c36, which added the
"skip full scan of index" mechanism (i.e. the _bt_vacuum_needs_cleanup()
logic).  The accuracy of btm_last_cleanup_num_heap_tuples accidentally
hinged upon _when_ the source value gets stored.  We now always store
btm_last_cleanup_num_heap_tuples in btvacuumcleanup().  This fixes the
issue because IndexVacuumInfo.num_heap_tuples (the source field) is
expected to accurately indicate the state of the table _after_ the
VACUUM completes inside btvacuumcleanup().

A backpatchable fix cannot easily be extracted from this commit.  A
targeted fix for the issue will follow in a later commit, though that
won't happen today.

I (pgeoghegan) have chosen to remove any mention of deleted pages in the
documentation of the vacuum_cleanup_index_scale_factor GUC/param, since
the presence of deleted (though unrecycled) pages is no longer of much
concern to users.  The vacuum_cleanup_index_scale_factor description in
the docs now seems rather unclear in any case, and it should probably be
rewritten in the near future.  Perhaps some passing mention of page
deletion will be added back at the same time.

Bump XLOG_PAGE_MAGIC due to nbtree WAL records using full XIDs now.

Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/CAH2-WznpdHvujGUwYZ8sihX=d5u-tRYhi-F4wnV2uN2zHpMUXw@mail.gmail.com
2021-02-24 18:41:34 -08:00
Amit Kapila 8a4f9522d0 Fix relcache reference leak introduced by ce0fdbfe97.
Author: Sawada Masahiko
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/CAD21AoA7ZEfsOXQ9HQqMv3QYGsEm2H5Wk5ic5S=mvzDf-3a3SA@mail.gmail.com
2021-02-25 07:48:24 +05:30
Michael Paquier bcf2667bf6 Fix some typos, grammar and style in docs and comments
The portions fixing the documentation are backpatched where needed.

Author: Justin Pryzby
Discussion: https://postgr.es/m/20210210235557.GQ20012@telsasoft.com
backpatch-through: 9.6
2021-02-24 16:13:17 +09:00
Peter Eisentraut 8ec8fe0f31 Message style fix
Don't quote type name placeholders.
2021-02-24 07:00:49 +01:00
Alvaro Herrera 5a65eacfdc
Fix confusion in comments about generate_gather_paths
d2d8a229bc introduced a new function generate_useful_gather_paths to
be used as a replacement for generate_gather_paths, but forgot to update
a couple of places that referenced the older function.

This is possibly not 100% complete (ref. create_ordered_paths), but it's
better than not changing anything.

Author: "Hou, Zhijie" <houzj.fnst@cn.fujitsu.com>
Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com>
Discussion: https://postgr.es/m/4ce1d5116fe746a699a6d29858c6a39a@G08CNEXMBPEKD05.g08.fujitsu.local
2021-02-23 20:05:15 -03:00
Alvaro Herrera 8deb6b38dc
Reinstate HEAP_XMAX_LOCK_ONLY|HEAP_KEYS_UPDATED as allowed
Commit 866e24d47d added an assert that HEAP_XMAX_LOCK_ONLY and
HEAP_KEYS_UPDATED cannot appear together, on the faulty assumption that
the latter necessarily referred to an update and not a tuple lock; but
that's wrong, because SELECT FOR UPDATE can use precisely that
combination, as evidenced by the amcheck test case added here.

Remove the Assert(), and also patch amcheck's verify_heapam.c to not
complain if the combination is found.  Also, out of overabundance of
caution, update (across all branches) README.tuplock to be more explicit
about this.

Author: Julien Rouhaud <rjuju123@gmail.com>
Reviewed-by: Mahendra Singh Thalor <mahi6run@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Discussion: https://postgr.es/m/20210124061758.GA11756@nol
2021-02-23 17:30:21 -03:00
Tom Lane 3db05e76f9 Suppress compiler warning in new regex match-all detection code.
gcc 10 is smart enough to notice that control could reach this
"hasmatch[depth]" assignment with depth < 0, but not smart enough
to know that that would require a badly broken NFA graph.  Change
the assert() to a plain runtime test to shut it up.

Per report from Andres Freund.

Discussion: https://postgr.es/m/20210223173437.b3ywijygsy6q42gq@alap3.anarazel.de
2021-02-23 13:55:34 -05:00
Alvaro Herrera d9d076222f
VACUUM: ignore indexing operations with CONCURRENTLY
As envisioned in commit c98763bf51, it is possible for VACUUM to
ignore certain transactions that are executing CREATE INDEX CONCURRENTLY
and REINDEX CONCURRENTLY for the purposes of computing Xmin; that's
because we know those transactions are not going to examine any other
tables, and are not going to execute anything else in the same
transaction.  (Only operations on "safe" indexes can be ignored: those
on indexes that are neither partial nor expressional).

This is extremely useful in cases where CIC/RC can run for a very long
time, because that used to be a significant headache for concurrent
vacuuming of other tables.

Reviewed-by: Matthias van de Meent <boekewurm+postgres@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/20210115133858.GA18931@alvherre.pgsql
2021-02-23 12:15:09 -03:00
Peter Eisentraut 6f6f284c7e Simplify printing of LSNs
Add a macro LSN_FORMAT_ARGS for use in printf-style printing of LSNs.
Convert all applicable code to use it.

Reviewed-by: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://www.postgresql.org/message-id/flat/CAExHW5ub5NaTELZ3hJUCE6amuvqAtsSxc7O+uK7y4t9Rrk23cw@mail.gmail.com
2021-02-23 10:27:02 +01:00
Amit Kapila ade89ba5f4 Fix an oversight in ReorderBufferFinishPrepared.
We don't have anything to decode in a transaction if ReorderBufferTXN
doesn't exist by the time we decode the commit prepared. So don't create a
new ReorderBufferTXN here. This is an oversight in commit a271a1b5.

Reported-by: Markus Wanner
Discussion: https://postgr.es/m/dbec82e2-dbd7-95a2-c6b6-e488cbbdf853@bluegap.ch
2021-02-23 09:47:41 +05:30
Amit Kapila bc617a7b1c Change the error message for logical replication authentication failure.
The authentication failure error message wasn't distinguishing whether
it is a physical replication or logical replication connection failure and
was giving incomplete information on what led to failure in case of logical
replication connection.

Author: Paul Martinez and Amit Kapila
Reviewed-by: Euler Taveira and Amit Kapila
Discussion: https://postgr.es/m/CACqFVBYahrAi2OPdJfUA3YCvn3QMzzxZdw0ibSJ8wouWeDtiyQ@mail.gmail.com
2021-02-23 09:11:22 +05:30
Alvaro Herrera 0f5505a881
Remove pointless HeapTupleHeaderIndicatesMovedPartitions calls
Pavan Deolasee recently noted that a few of the
HeapTupleHeaderIndicatesMovedPartitions calls added by commit
5db6df0c01 are useless, since they are done after comparing t_self
with t_ctid.  But because t_self can never be set to the magical values
that indicate that the tuple moved partition, this can never succeed: if
the first test fails (so we know t_self equals t_ctid), necessarily the
second test will also fail.

So these checks can be removed and no harm is done.  There's no bug
here, just a code legibility issue.

Reported-by: Pavan Deolasee <pavan.deolasee@gmail.com>
Discussion: https://postgr.es/m/20200929164411.GA15497@alvherre.pgsql
2021-02-22 16:51:44 -03:00