Since commit 859b3003de we only build extended statistics for individual
relations, ignoring the child relations. This resolved the issue with
updating catalog tuple twice, but we still tried to use the statistics
when calculating estimates for the whole inheritance tree. When the
relations contain very distinct data, it may produce bogus estimates.
This is roughly the same issue 427c6b5b9 addressed ~15 years ago, and we
fix it the same way - by ignoring extended statistics when calculating
estimates for the inheritance tree as a whole. We still consider
extended statistics when calculating estimates for individual child
relations, of course.
This may result in plan changes due to different estimates, but if the
old statistics were not describing the inheritance tree particularly
well it's quite likely the new plans is actually better.
Report and patch by Justin Pryzby, minor fixes and cleanup by me.
Backpatch all the way back to PostgreSQL 10, where extended statistics
were introduced (same as 859b3003de).
Author: Justin Pryzby
Reported-by: Justin Pryzby
Backpatch-through: 10
Discussion: https://postgr.es/m/20210923212624.GI831%40telsasoft.com
Provide a developer-only GUC allow_in_place_tablespaces, disabled by
default. When enabled, tablespaces can be created with an empty
LOCATION string, meaning that they should be created as a directory
directly beneath pg_tblspc. This can be used for new testing scenarios,
in a follow-up patch. Not intended for end-user usage, since it might
confuse backup tools that expect symlinks.
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/CA%2BhUKGKpRWQ9SxdxxDmTBCJoR0YnFpMBe7kyzY8SUQk%2BHeskxg%40mail.gmail.com
Commit 7745bc352 intended to ensure that whole-row Vars would be
printed with "::type" decoration in all contexts where plain
"var.*" notation would result in star-expansion, notably in
ROW() and VALUES() constructs. However, it missed the case of
INSERT with a single-row VALUES, as reported by Timur Khanjanov.
Nosing around ruleutils.c, I found a second oversight: the
code for RowCompareExpr generates ROW() notation without benefit
of an actual RowExpr, and naturally it wasn't in sync :-(.
(The code for FieldStore also does this, but we don't expect that
to generate strictly parsable SQL anyway, so I left it alone.)
Back-patch to all supported branches.
Discussion: https://postgr.es/m/efaba6f9-4190-56be-8ff2-7a1674f9194f@intrans.baku.az
The recent refactoring done in ac7c807 makes this move possible and
simple, as this just moves some code around. This reduces the size of
elog.c by 7%.
Author: Michael Paquier, Sehrope Sarkuni
Reviewed-by: Nathan Bossart
Discussion: https://postgr.es/m/CAH7T-aqswBM6JWe4pDehi1uOiufqe06DJWaU5=X7dDLyqUExHg@mail.gmail.com
simply moves the routines related to csvlog into their own file
This refactors the following routines and facilities coming from
elog.c, to ease their use across multiple log destinations:
- Start timestamp, including its reset, to store when a process has been
started.
- The log timestamp, associated to an entry (the same timestamp is used
when logging across multiple destinations).
- Routine deciding if a query can be logged or not.
- The backend type names, depending on the process that logs any
information (postmaster, bgworker name or just GetBackendTypeDesc() with
a regular backend).
- Write of logs using the logging piped protocol, with the log collector
enabled.
- Error severity converted to a string.
These refactored routines will be used for some follow-up changes
to move all the csvlog logic into its own file and to potentially add
JSON as log destination, reducing the overall size of elog.c as the end
result.
Author: Michael Paquier, Sehrope Sarkuni
Reviewed-by: Nathan Bossart
Discussion: https://postgr.es/m/CAH7T-aqswBM6JWe4pDehi1uOiufqe06DJWaU5=X7dDLyqUExHg@mail.gmail.com
Previously pg_log_backend_memory_contexts() could request to
log the memory contexts of backends, but not of auxiliary processes
such as checkpointer. This commit enhances the function so that
it can also send the request to auxiliary processes. It's useful to
look at the memory contexts of those processes for debugging purpose
and better understanding of the memory usage pattern of them.
Note that pg_log_backend_memory_contexts() cannot send the request
to logger or statistics collector. Because this logging request
mechanism is based on shared memory but those processes aren't
connected to that.
Author: Bharath Rupireddy
Reviewed-by: Vignesh C, Kyotaro Horiguchi, Fujii Masao
Discussion: https://postgr.es/m/CALj2ACU1nBzpacOK2q=a65S_4+Oaz_rLTsU1Ri0gf7YUmnmhfQ@mail.gmail.com
The existing cryptohash facility was causing problems in some code paths
related to MD5 (frontend and backend) that relied on the fact that the
only type of error that could happen would be an OOM, as the MD5
implementation used in PostgreSQL ~13 (the in-core implementation is
used when compiling with or without OpenSSL in those older versions),
could fail only under this circumstance.
The new cryptohash facilities can fail for reasons other than OOMs, like
attempting MD5 when FIPS is enabled (upstream OpenSSL allows that up to
1.0.2, Fedora and Photon patch OpenSSL 1.1.1 to allow that), so this
would cause incorrect reports to show up.
This commit extends the cryptohash APIs so as callers of those routines
can fetch more context when an error happens, by using a new routine
called pg_cryptohash_error(). The error states are stored within each
implementation's internal context data, so as it is possible to extend
the logic depending on what's suited for an implementation. The default
implementation requires few error states, but OpenSSL could report
various issues depending on its internal state so more is needed in
cryptohash_openssl.c, and the code is shaped so as we are always able to
grab the necessary information.
The core code is changed to adapt to the new error routine, painting
more "const" across the call stack where the static errors are stored,
particularly in authentication code paths on variables that provide
log details. This way, any future changes would warn if attempting to
free these strings. The MD5 authentication code was also a bit blurry
about the handling of "logdetail" (LOG sent to the postmaster), so
improve the comments related that, while on it.
The origin of the problem is 87ae969, that introduced the centralized
cryptohash facility. Extra changes are done for pgcrypto in v14 for the
non-OpenSSL code path to cope with the improvements done by this
commit.
Reported-by: Michael Mühlbeyer
Author: Michael Paquier
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/89B7F072-5BBE-4C92-903E-D83E865D9367@trivadis.com
Backpatch-through: 14
Since this function is defined to accept pg_node_tree values, it could
get applied to any nodetree that can appear in a cataloged pg_node_tree
column. Some such cases can't be supported --- for example, its API
doesn't allow providing referents for more than one relation --- but
we should try to throw a user-facing error rather than an internal
error when encountering such a case.
In support of this, extend expression_tree_walker/mutator to be sure
they'll work on any such node tree (which basically means adding
support for relpartbound node types). That allows us to run pull_varnos
and check for the case of multiple relations before we start processing
the tree. The alternative of changing the low-level error thrown for an
out-of-range varno isn't appealing, because that could mask actual bugs
in other usages of ruleutils.
Per report from Justin Pryzby. This is basically cosmetic, so no
back-patch.
Discussion: https://postgr.es/m/20211219205422.GT17618@telsasoft.com
Adjust the error texts used for unrecognized/unsupported datetime
units so that there are just two strings to translate, not two
per datatype. Along the way, follow our usual error message style
of not double-quoting type names, and instead making sure that we
say the name is a type. Fix a couple of places in date.c that
were using the wrong one of "unrecognized" and "unsupported".
Nikhil Benesch, with a bit more editing by me
Discussion: https://postgr.es/m/CAPWqQZTURGixmbMH2_Z3ZtWGA0ANjUb9bwtkkxSxSfDeFHuM6Q@mail.gmail.com
This seems like a clearer name for what it does now.
Provide a compatibility macro so that extensions don't have to convert
to the new name right away.
Discussion: https://postgr.es/m/116024.1640111629@sss.pgh.pa.us
Commit 75d22069e made SET print a warning if you tried to set an
unrecognized parameter within namespace previously reserved by an
extension. It seems better for that to be an outright error though,
for the same reason that we don't let you set unrecognized unqualified
parameter names. In any case, the preceding implementation was
inefficient and erroneous. Perform the check in a more appropriate
spot, and be more careful about prefix-match cases.
Discussion: https://postgr.es/m/116024.1640111629@sss.pgh.pa.us
Extensions that define any custom GUCs should call
EmitWarningsOnPlaceholders after doing so, to help catch misspellings.
Many of our contrib modules hadn't gotten the memo on that, though.
Also add such calls to src/test/modules extensions that have GUCs.
While these aren't really user-facing, they should illustrate good
practice not faulty practice.
Shinya Kato
Discussion: https://postgr.es/m/524fa2c0a34f34b68fbfa90d0760d515@oss.nttdata.com
pg_strtouint64() is a wrapper around strtoull/strtoul/_strtoui64, but
it seems no longer necessary to have this indirection.
msvc/Solution.pm claims HAVE_STRTOULL, so the "MSVC only" part seems
unnecessary. Also, we have code in c.h to substitute alternatives for
strtoull() if not found, and that would appear to cover all currently
supported platforms, so having a further fallback in pg_strtouint64()
seems unnecessary.
Therefore, we could remove pg_strtouint64(), and use strtoull()
directly in all call sites. However, it seems useful to keep a
separate notation for parsing exactly 64-bit integers, matching the
type definition int64/uint64. For that, add new macros strtoi64() and
strtou64() in c.h as thin wrappers around strtol()/strtoul() or
strtoll()/stroull(). This makes these functions available everywhere
instead of just in the server code, and it makes the function naming
notably different from the pg_strtointNN() functions in numutils.c,
which have a different API.
Discussion: https://www.postgresql.org/message-id/flat/a3df47c9-b1b4-29f2-7e91-427baf8b75a3%40enterprisedb.com
The API spec for lookup_rowtype_tupdesc previously said you could use
either ReleaseTupleDesc or DecrTupleDescRefCount. However, the latter
choice means the caller must be certain that the returned tupdesc is
refcounted. I don't recall right now whether that was always true
when this spec was written, but it's certainly not always true since
we introduced shared record typcaches for parallel workers. That means
that callers using DecrTupleDescRefCount are dependent on typcache
behavior details that they probably shouldn't be. Hence, change the API
spec to say that you must call ReleaseTupleDesc, and fix the half-dozen
callers that weren't.
AFAICT this is just future-proofing, there's no live bug here.
So no back-patch.
Per gripe from Chapman Flack.
Discussion: https://postgr.es/m/61B901A4.1050808@anastigmatix.net
Borrow the logic that's long been used in tuplesort.c: instead
of physically swapping the data in two heap entries, keep the
value that's being sifted up or down in a local variable, and
just move the other values as necessary. This makes the code
shorter as well as faster. It's not clear that any current
callers are really time-critical enough to notice, but we
might as well code heap maintenance the same way everywhere.
Ma Liangzhu and Tom Lane
Discussion: https://postgr.es/m/17336-fc4e522d26a750fd@postgresql.org
This could only matter if (a) long is wider than int, and (b) the heap
of free blocks exceeds UINT_MAX entries, which seems pretty unlikely.
Still, it's a theoretical bug, so backpatch to v13 where the typo came
in (in commit c02fdc922).
In passing, also make swap_nodes() use consistent datatypes.
Ma Liangzhu
Discussion: https://postgr.es/m/17336-fc4e522d26a750fd@postgresql.org
Nobody has filled in these stubs for upwards of twenty years,
so it's time to drop the idea that they might get implemented
any day now. The associated pg_operator and pg_proc entries
are just confusing wastes of space.
Per complaint from Anton Voloshin.
Discussion: https://postgr.es/m/3426566.1638832718@sss.pgh.pa.us
geo_ops.c contains half a dozen functions that are just stubs throwing
ERRCODE_FEATURE_NOT_SUPPORTED. Since it's been like that for more
than twenty years, there's clearly not a lot of interest in filling in
the stubs. However, I'm uncomfortable with deleting poly_distance(),
since every other geometric type supports a distance-to-another-object-
of-the-same-type function. We can easily add this capability by
cribbing from poly_overlap() and path_distance().
It's possible that the (existing) test case for this will show some
numeric instability, but hopefully the buildfarm will expose it if so.
In passing, improve the documentation to try to explain why polygons
are distinct from closed paths in the first place.
Discussion: https://postgr.es/m/3426566.1638832718@sss.pgh.pa.us
It's not great that RecoveryInProgress() calls InitXLOGAccess(),
because a status inquiry function typically shouldn't have the side
effect of performing initializations. We could fix that by calling
InitXLOGAccess() from some other place, but instead, let's remove it
altogether.
One thing InitXLogAccess() did is initialize wal_segment_size, but it
doesn't need to do that. In the postmaster, PostmasterMain() calls
LocalProcessControlFile(), and all child processes will inherit that
value -- except in EXEC_BACKEND bulds, but then each backend runs
SubPostmasterMain() which also calls LocalProcessControlFile().
The other thing InitXLOGAccess() did is update RedoRecPtr and
doPageWrites, but that's not critical, because all code that uses
them will just retry if it turns out that they've changed. The
only difference is that most code will now see an initial value that
is definitely invalid instead of one that might have just been way
out of date, but that will only happen once per backend lifetime,
so it shouldn't be a big deal.
Patch by me, reviewed by Nathan Bossart, Michael Paquier, Andres
Freund, Heikki Linnakangas, and Álvaro Herrera.
Discussion: http://postgr.es/m/CA+TgmoY7b65qRjzHN_tWUk8B4sJqk1vj1d31uepVzmgPnZKeLg@mail.gmail.com
The idea here is that when a performance problem is known to have
occurred at a certain point in time, it's a good thing if there is
some information available from the logs to help figure out what
might have happened around that time.
This change attracted an above-average amount of dissent, because
it means that a server with default settings will produce some amount
of log output even if nothing has gone wrong. However, by my count,
the mailing list discussion had about twice as many people in favor
of the change as opposed. The reasons for believing that the extra
log output is not an issue in practice are: (1) the rate at which
messages can be generated by this setting is bounded to one every
few minutes on a properly-configured system and (2) production
systems tend to have a lot more junk in the log from that due to
failed connection attempts, ERROR messages generated by application
activity, and the like.
Bharath Rupireddy, reviewed by Fujii Masao and by me. Many other
people commented on the thread, but as far as I can see that was
discussion of the merits of the change rather than review of the
patch.
Discussion: https://postgr.es/m/CALj2ACX-rW_OeDcp4gqrFUAkf1f50Fnh138dmkd0JkvCNQRKGA@mail.gmail.com
The multirange_get_range() function fails when two boundaries of the same
range have different alignments. Fix that by adding proper pointer alignment.
Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/17300-dced2d01ddeb1f2f%40postgresql.org
Backpatch-through: 14
Extend the foreign key ON DELETE actions SET NULL and SET DEFAULT by
allowing the specification of a column list, like
CREATE TABLE posts (
...
FOREIGN KEY (tenant_id, author_id) REFERENCES users ON DELETE SET NULL (author_id)
);
If a column list is specified, only those columns are set to
null/default, instead of all the columns in the foreign-key
constraint.
This is useful for multitenant or sharded schemas, where the tenant or
shard ID is included in the primary key of all tables but shouldn't be
set to null.
Author: Paul Martinez <paulmtz@google.com>
Discussion: https://www.postgresql.org/message-id/flat/CACqFVBZQyMYJV=njbSMxf+rbDHpx=W=B7AEaMKn8dWn9OZJY7w@mail.gmail.com
The chr() function used PG_GETARG_UINT32() even though the argument is
declared as (signed) integer. As a result, you can pass negative
arguments to this function and it internally interprets them as
positive. Ultimately ends up being harmless, but it seems wrong, so
fix this and rearrange the internal error checking a bit to
accommodate this.
Another case was in the documentation, where example code used
PG_GETARG_UINT32() with an argument declared as signed integer.
Reviewed-by: Nathan Bossart <bossartn@amazon.com>
Discussion: https://www.postgresql.org/message-id/flat/7e43869b-d412-8f81-30a3-809783edc9a3%40enterprisedb.com
This commit fixes a couple of inconsistencies in the descriptions of
some GUCs, while making their wording more general regarding the units
they rely on.
For most of them, this removes the use of terms like "N seconds" or "N
bytes", which may not apply easily to all the languages these strings
are translated to (from my own experience, this works in French and
English, less in Japanese).
Per debate between the authors listed below.
Author: Justin Pryzby, Michael Paquier
Discussion: https://postgr.es/m/20211129030833.GJ17618@telsasoft.com
An extension can already de facto reserve a GUC prefix using
EmitWarningsOnPlaceholders(). But this was only checked against
settings that exist at the time the extension is loaded (or the
extension chooses to call this). No diagnostic is given when a SET
command later uses a nonexisting setting with a custom prefix.
With this change, EmitWarningsOnPlaceholders() saves the prefixes it
reserves in a list, and SET checks when it finds a "placeholder"
setting whether it belongs to a reserved prefix and issues a warning
in that case.
Add a regression test that checks the patch using the "plpgsql"
registered prefix.
Author: Florin Irion <florin.irion@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/flat/CA+HEvJDhWuuTpGTJT9Tgbdzm4QS4EzPAwDBScWK18H2Q=FVJFw@mail.gmail.com
When determining whether an index update may be skipped by using HOT, we
can ignore attributes indexed only by BRIN indexes. There are no index
pointers to individual tuples in BRIN, and the page range summary will
be updated anyway as it relies on visibility info.
This also removes rd_indexattr list, and replaces it with rd_attrsvalid
flag. The list was not used anywhere, and a simple flag is sufficient.
Patch by Josef Simanek, various fixes and improvements by me.
Author: Josef Simanek
Reviewed-by: Tomas Vondra, Alvaro Herrera
Discussion: https://postgr.es/m/CAFp7QwpMRGcDAQumN7onN9HjrJ3u4X3ZRXdGFT0K5G2JWvnbWg%40mail.gmail.com
fsstate in process_pending_requests (in postgres_fdw.c) was added in
8998e3cafa as an assertion-only variable, 1ec7fca859 stated using
the variable outside of assertions.
rd_index in get_index_column_opclass (in lsyscache.c) was introduced
in 2a6368343f, and then promptly used in the fix commit 7e04160390
shortly thereafter.
This removes the PG_USED_FOR_ASSERTS_ONLY variable decoration from
the above mentioned variables.
Reviewed-by: Greg Nancarrow <gregn4422@gmail.com>
Discussion: https://postgr.es/m/F959106C-0F21-43A5-B2AE-D007D51ACBEE@yesql.se
This commit fixes some issues with GUCs:
- enable_incremental_sort was not marked as GUC_EXPLAIN, causing it to
not be listed in the output of EXPLAIN (SETTINGS) if using a value
different than the default, contrary to the other planner-level GUCs.
- trace_recovery_messages missed GUC_NOT_IN_SAMPLE, like the other
developer options.
- ssl_renegotiation_limit should be marked as COMPAT_OPTIONS_PREVIOUS.
While on it, this fixes one incorrect comment related to
autovacuum_freeze_max_age, and improves the descriptions of some other
GUCs, recently introduced.
Extracted from a larger patch set by the same author.
Author: Justin Pryzby
Description: https://postgr.es/m/20211129030833.GJ17618@telsasoft.com
This commit adds a new system view pg_stat_subscription_workers, that
shows information about any errors which occur during the application of
logical replication changes as well as during performing initial table
synchronization. The subscription statistics entries are removed when the
corresponding subscription is removed.
It also adds an SQL function pg_stat_reset_subscription_worker() to reset
single subscription errors.
The contents of this view can be used by an upcoming patch that skips the
particular transaction that conflicts with the existing data on the
subscriber.
This view can be extended in the future to track other xact related
statistics like the number of xacts committed/aborted for subscription
workers.
Author: Masahiko Sawada
Reviewed-by: Greg Nancarrow, Hou Zhijie, Tang Haiying, Vignesh C, Dilip Kumar, Takamichi Osumi, Amit Kapila
Discussion: https://postgr.es/m/CAD21AoDeScrsHhLyEPYqN3sydg6PxAPVBboK=30xJfUVihNZDA@mail.gmail.com
Standardize on xoroshiro128** as our basic PRNG algorithm, eliminating
a bunch of platform dependencies as well as fundamentally-obsolete PRNG
code. In addition, this API replacement will ease replacing the
algorithm again in future, should that become necessary.
xoroshiro128** is a few percent slower than the drand48 family,
but it can produce full-width 64-bit random values not only 48-bit,
and it should be much more trustworthy. It's likely to be noticeably
faster than the platform's random(), depending on which platform you
are thinking about; and we can have non-global state vectors easily,
unlike with random(). It is not cryptographically strong, but neither
are the functions it replaces.
Fabien Coelho, reviewed by Dean Rasheed, Aleksander Alekseev, and myself
Discussion: https://postgr.es/m/alpine.DEB.2.22.394.2105241211230.165418@pseudo
Memoize would always use the hash equality operator for the cache key
types to determine if the current set of parameters were the same as some
previously cached set. Certain types such as floating points where -0.0
and +0.0 differ in their binary representation but are classed as equal by
the hash equality operator may cause problems as unless the join uses the
same operator it's possible that whichever join operator is being used
would be able to distinguish the two values. In which case we may
accidentally return in the incorrect rows out of the cache.
To fix this here we add a binary mode to Memoize to allow it to the
current set of parameters to previously cached values by comparing
bit-by-bit rather than logically using the hash equality operator. This
binary mode is always used for LATERAL joins and it's used for normal
joins when any of the join operators are not hashable.
Reported-by: Tom Lane
Author: David Rowley
Discussion: https://postgr.es/m/3004308.1632952496@sss.pgh.pa.us
Backpatch-through: 14, where Memoize was added
This commit adds a set of functions able to look at the contents of
various paths related to replication slots:
- pg_ls_logicalsnapdir, for pg_logical/snapshots/
- pg_ls_logicalmapdir, for pg_logical/mappings/
- pg_ls_replslotdir, for pg_replslot/<slot_name>/
These are intended to be used by monitoring tools. Unlike pg_ls_dir(),
execution permission can be granted to non-superusers. Roles members of
pg_monitor gain have access to those functions.
Bump catalog version.
Author: Bharath Rupireddy
Reviewed-by: Nathan Bossart, Justin Pryzby
Discussion: https://postgr.es/m/CALj2ACWsfizZjMN6bzzdxOk1ADQQeSw8HhEjhmVXn_Pu+7VzLw@mail.gmail.com
This allows a later commit to reduce the number of branches in performance
sensitive functions during normal running, compared to a very minor saving
during bootstrapping.
Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-By: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CAAKRu_Yeg+vh6SHNEo1+=O7e-BPX35cU0XQM=YwQRnkFyv_y+w@mail.gmail.com
This fills in some gaps in planner support for starts_with() and
the equivalent ^@ operator:
* A condition such as "textcol ^@ constant" can now use a regular
btree index, not only an SP-GiST index, so long as the index's
collation is C. (This works just like "textcol LIKE 'foo%'".)
* "starts_with(textcol, constant)" can be optimized the same as
"textcol ^@ constant".
* Fixed-prefix LIKE and regex patterns are now more like starts_with()
in another way: if you apply one to an SPGiST-indexed column, you'll
get an index condition using ^@ rather than two index conditions with
>= and <.
Per a complaint from Shay Rojansky. Patch by me; thanks to
Nathan Bossart for review.
Discussion: https://postgr.es/m/232599.1633800229@sss.pgh.pa.us
If a SQL-standard function body contains an INSERT ... SELECT statement,
any function parameters referenced within the SELECT were always printed
in $N style, rather than using the parameter name if any. While not
strictly incorrect, this wasn't the intention, and it's inconsistent
with the way that such parameters would be printed in any other kind
of statement.
The cause is that the recursion to get_query_def from
get_insert_query_def neglected to pass down the context->namespaces
list, passing constant NIL instead. This is a very ancient oversight,
but AFAICT it had no visible consequences before commit e717a9a18
added an outermost namespace with function parameters. We don't allow
INSERT ... SELECT as a sub-query, except in a top-level WITH clause,
where it couldn't contain any outer references that might need to access
upper namespaces. So although that's arguably a bug, I don't see any
point in changing it before v14.
In passing, harden the code added to get_parameter by e717a9a18 so that
it won't crash if a PARAM_EXTERN Param appears in an unexpected place.
Per report from Erki Eessaar. Code fix by me, regression test case
by Masahiko Sawada.
Discussion: https://postgr.es/m/AM9PR01MB8268347BED344848555167FAFE949@AM9PR01MB8268.eurprd01.prod.exchangelabs.com
At present, there is an undocumented coding rule that you must call
RecoveryInProgress(), or do something else that results in a call
to InitXLogInsert(), before trying to write WAL. Otherwise, the
WAL construction buffers won't be initialized, resulting in
failures.
Since it's not good to rely on a status inquiry function like
RecoveryInProgress() having the side effect of initializing
critical data structures, instead do the initialization eariler,
when the backend first starts up.
Patch by me. Reviewed by Nathan Bossart and Michael Paquier.
Discussion: http://postgr.es/m/CA+TgmoY7b65qRjzHN_tWUk8B4sJqk1vj1d31uepVzmgPnZKeLg@mail.gmail.com
pg_stat_get_slru() in pgstatfuncs.c would point to one element after the
end of the array PgStat_SLRUStats when finishing to scan its entries.
This had no direct consequences as no data from the extra memory area
was read, but static analyzers would rightfully complain here. So let's
be clean.
While on it, this adds one regression test in the area reserved for
system views.
Reported-by: Alexander Kozhemyakin, via AddressSanitizer
Author: Kyotaro Horiguchi
Discussion: https://postgr.es/m/17280-37da556e86032070@postgresql.org
Backpatch-through: 13
The tsvector data type has always forbidden lexemes to be empty.
However, array_to_tsvector() didn't get that memo, and would
allow an empty-string array element to become an empty lexeme.
This could result in dump/restore failures later, not to mention
whatever semantic issues might be behind the original prohibition.
However, other functions that take a plain text input directly as
a lexeme value do not need a similar restriction, because they only
match the string against existing tsvector entries. In particular
it'd be a bad idea to make ts_delete() reject empty strings, since
that is the most convenient way to clean up any bad data that might
have gotten into a tsvector column via this bug.
Reflecting on that, let's also remove the prohibition against NULL
array elements in tsvector_delete_arr and tsvector_setweight_by_filter.
It seems more consistent to ignore them, as an empty-string element
would be ignored.
There's a case for back-patching this, since it's clearly a bug fix.
On balance though, it doesn't seem like something to change in a
minor release.
Jean-Christophe Arnu
Discussion: https://postgr.es/m/CAHZmTm1YVndPgUVRoag2WL0w900XcoiivDDj-gTTYBsG25c65A@mail.gmail.com
A new option "FOR ALL TABLES IN SCHEMA" in Create/Alter Publication allows
one or more schemas to be specified, whose tables are selected by the
publisher for sending the data to the subscriber.
The new syntax allows specifying both the tables and schemas. For example:
CREATE PUBLICATION pub1 FOR TABLE t1,t2,t3, ALL TABLES IN SCHEMA s1,s2;
OR
ALTER PUBLICATION pub1 ADD TABLE t1,t2,t3, ALL TABLES IN SCHEMA s1,s2;
A new system table "pg_publication_namespace" has been added, to maintain
the schemas that the user wants to publish through the publication.
Modified the output plugin (pgoutput) to publish the changes if the
relation is part of schema publication.
Updates pg_dump to identify and dump schema publications. Updates the \d
family of commands to display schema publications and \dRp+ variant will
now display associated schemas if any.
Author: Vignesh C, Hou Zhijie, Amit Kapila
Syntax-Suggested-by: Tom Lane, Alvaro Herrera
Reviewed-by: Greg Nancarrow, Masahiko Sawada, Hou Zhijie, Amit Kapila, Haiying Tang, Ajin Cherian, Rahila Syed, Bharath Rupireddy, Mark Dilger
Tested-by: Haiying Tang
Discussion: https://www.postgresql.org/message-id/CALDaNm0OANxuJ6RXqwZsM1MSY4s19nuH3734j4a72etDwvBETQ@mail.gmail.com
Remove superuser check, allowing any user granted permissions on
pg_log_backend_memory_contexts() to log the memory contexts of any
backend.
Note that this could allow a privileged non-superuser to log the
memory contexts of a superuser backend, but as discussed, that does
not seem to be a problem.
Reviewed-by: Nathan Bossart, Bharath Rupireddy, Michael Paquier, Kyotaro Horiguchi, Andres Freund
Discussion: https://postgr.es/m/e5cf6684d17c8d1ef4904ae248605ccd6da03e72.camel@j-davis.com
Users sometimes get concerned whe they start the server and it
emits a few messages and then doesn't emit any more messages for
a long time. Generally, what's happening is either that the
system is taking a long time to apply WAL, or it's taking a
long time to reset unlogged relations, or it's taking a long
time to fsync the data directory, but it's not easy to tell
which is the case.
To fix that, add a new 'log_startup_progress_interval' setting,
by default 10s. When an operation that is known to be potentially
long-running takes more than this amount of time, we'll log a
status update each time this interval elapses.
To avoid undesirable log chatter, don't log anything about WAL
replay when in standby mode.
Nitin Jadhav and Robert Haas, reviewed by Amul Sul, Bharath
Rupireddy, Justin Pryzby, Michael Paquier, and Álvaro Herrera.
Discussion: https://postgr.es/m/CA+TgmoaHQrgDFOBwgY16XCoMtXxsrVGFB2jNCvb7-ubuEe1MGg@mail.gmail.com
Discussion: https://postgr.es/m/CAMm1aWaHF7VE69572_OLQ+MgpT5RUiUDgF1x5RrtkJBLdpRj3Q@mail.gmail.com
In selectnewtape(), use 'nOutputTapes' rather than 'nOutputRuns' in the
check for whether to start a new tape or to append a new run to an
existing tape. Until 'maxTapes' is reached, nOutputTapes is always equal
to nOutputRuns, so it doesn't change the logic, but it seems more logical
to compare # of tapes with # of tapes. Also, currently maxTapes is never
modified after the merging begins, but written this way, the code would
still work if it was. (Although the nOutputRuns == nOutputTapes assertion
would need to be removed and using nOutputRuns % nOutputTapes to
distribute the runs evenly across the tapes wouldn't do a good job
anymore).
Similarly in mergeruns(), change to USEMEM(state->tape_buffer_mem) to
account for the memory used for tape buffers. It's equal to availMem
currently, but tape_buffer_mem is more direct and future-proof. For
example, if we changed the logic to only allocate half of the remaining
memory to tape buffers, USEMEM(state->tape_buffer_mem) would still be
correct.
Coverity complained about these. Hopefully this patch helps it to
understand the logic better. Thanks to Tom Lane for initial analysis.
The purpose of commit 8a54e12a38 was to
fix this, and it sufficed when the PREPARE TRANSACTION completed before
the CIC looked for lock conflicts. Otherwise, things still broke. As
before, in a cluster having used CIC while having enabled prepared
transactions, queries that use the resulting index can silently fail to
find rows. It may be necessary to reindex to recover from past
occurrences; REINDEX CONCURRENTLY suffices. Fix this for future index
builds by making CIC wait for arbitrarily-recent prepared transactions
and for ordinary transactions that may yet PREPARE TRANSACTION. As part
of that, have PREPARE TRANSACTION transfer locks to its dummy PGPROC
before it calls ProcArrayClearTransaction(). Back-patch to 9.6 (all
supported versions).
Andrey Borodin, reviewed (in earlier versions) by Andres Freund.
Discussion: https://postgr.es/m/01824242-AA92-4FE9-9BA7-AEBAFFEA3D0C@yandex-team.ru
CIC and REINDEX CONCURRENTLY assume backends see their catalog changes
no later than each backend's next transaction start. That failed to
hold when a backend absorbed a relevant invalidation in the middle of
running RelationBuildDesc() on the CIC index. Queries that use the
resulting index can silently fail to find rows. Fix this for future
index builds by making RelationBuildDesc() loop until it finishes
without accepting a relevant invalidation. It may be necessary to
reindex to recover from past occurrences; REINDEX CONCURRENTLY suffices.
Back-patch to 9.6 (all supported versions).
Noah Misch and Andrey Borodin, reviewed (in earlier versions) by Andres
Freund.
Discussion: https://postgr.es/m/20210730022548.GA1940096@gust.leadboat.com
The code for initializing the tapes on each merge iteration was skipped
in a parallel worker. I put the !WORKER(state) check in wrong place while
rebasing the patch.
That caused failures in the index build in 'multiple-row-versions'
isolation test, in multiple buildfarm members. On my laptop it was easier
to reproduce by building an index on a larger table, so that you got a
parallel sort more reliably.
The previous commit 65014000b3 changed the variable passed to elog
from an int64 to a size_t variable, but neglected to change the modifier
in the format string accordingly.
Per failure on buildfarm member lapwing.
The advantage of polyphase merge is that it can reuse the input tapes as
output tapes efficiently, but that is irrelevant on modern hardware, when
we can easily emulate any number of tape drives. The number of input tapes
we can/should use during merging is limited by work_mem, but output tapes
that we are not currently writing to only cost a little bit of memory, so
there is no need to skimp on them.
This makes sorts that need multiple merge passes faster.
Discussion: https://www.postgresql.org/message-id/420a0ec7-602c-d406-1e75-1ef7ddc58d83%40iki.fi
Reviewed-by: Peter Geoghegan, Zhihong Yu, John Naylor
All the tape functions, like LogicalTapeRead and LogicalTapeWrite, now
take a LogicalTape as argument, instead of LogicalTapeSet+tape number.
You can create any number of LogicalTapes in a single LogicalTapeSet, and
you don't need to decide the number upfront, when you create the tape set.
This makes the tape management in hash agg spilling in nodeAgg.c simpler.
Discussion: https://www.postgresql.org/message-id/420a0ec7-602c-d406-1e75-1ef7ddc58d83%40iki.fi
Reviewed-by: Peter Geoghegan, Zhihong Yu, John Naylor
Commit 3f50b8263 had an oversight: formerly, to deparse expressions
attached to a plan node, it was only necessary to update the
deparse_namespace ancestors list alongside calling set_deparse_plan.
Now it's necessary to update the ancestors list *first*, because
set_deparse_plan consults it, and one call site got that wrong.
This error was masked in most cases because explain.c uses just one
List object for the ancestors list, updating it in-place as the plan
is scanned, so that we accidentally had the right List assigned to
dpns->ancestors before it was needed. It would fail only if a
WorkTableScan node were the first one that we tried to deparse a
subexpression of.
Per report from Markus Winand. Like the previous patch,
back-patch to v14.
Discussion: https://postgr.es/m/648B0505-AA57-42C2-A2DA-E551DE46FA15@winand.at
send_message_to_server_log() would force a redirection of a log entry to
stderr in some cases for csvlog, like the syslogger not being available
yet. If this happens, csvlog would fall back to stderr to log
some information rather than nothing. The code was organized so as
stderr is done before csvlog, with csvlog checking that stderr did not
happen yet with a reversed condition. With this code organization, it
could be possible to lose some messages if running Postgres as a service
on WIN32, as there is no usable stderr, and the handling of the
StringInfoData holding the message for stderr was rather confusing
because of that.
This commit moves the csvlog handling to be before stderr, as as we are
able to track down if it is necessary to log something to stderr. The
reduces the handling of stderr to be in a single code path, adding a
fallback to event logs for a WIN32 service. This also simplifies the
way we handle the StringInfoData for stderr, making easier the
integration of new file-based log destinations. I got to play with
services and event logs on Windows while checking this change.
Reviewed-by: Chris Bandy
Discussion: https://postgr.es/m/YV0vwBovEKf1WXkl@paquier.xyz
This fixes a loss of precision that occurs when the first input is
very close to 1, so that its logarithm is very small.
Formerly, during the initial low-precision calculation to estimate the
result weight, the logarithm was computed to a local rscale that was
capped to NUMERIC_MAX_DISPLAY_SCALE (1000). However, the base may be
as close as 1e-16383 to 1, hence its logarithm may be as small as
1e-16383, and so the local rscale needs to be allowed to exceed 16383,
otherwise all precision is lost, leading to a poor choice of rscale
for the full-precision calculation.
Fix this by removing the cap on the local rscale during the initial
low-precision calculation, as we already do in the full-precision
calculation. This doesn't change the fact that the initial calculation
is a low-precision approximation, computing the logarithm to around 8
significant digits, which is very fast, especially when the base is
very close to 1.
Patch by me, reviewed by Alvaro Herrera.
Discussion: https://postgr.es/m/CAEZATCV-Ceu%2BHpRMf416yUe4KKFv%3DtdgXQAe5-7S9tD%3D5E-T1g%40mail.gmail.com
A couple of newer ones are available. There are no functional
differences, but let's get them in anyway, so that there is no
surprise diff next time someone wants to do some actual work in this
area.
get_variable_range() would incautiously believe that statistics
containing only an MCV list are sufficient to derive a range estimate.
That's okay for an enum-like column that contains only MCVs, but
otherwise the estimate could be pretty bad. Make it report that the
range is indeterminate unless the MCVs plus nullfrac account for
the whole table.
I don't think this needs a dedicated test case, since a quick code
coverage check verifies that the existing regression tests traverse
all the alternatives. There is room to doubt that a future-proof
test case could be built anyway, given that the submitted example
accidentally doesn't fail before v11.
Per bug #17207 from Simon Perepelitsa. Back-patch to v10.
In principle this has been broken all along, but I'm hesitant to
make such changes in 9.6, since if anyone is unhappy with 9.6.24's
behavior there will be no second chance to fix it.
Discussion: https://postgr.es/m/17207-5265aefa79e333b4@postgresql.org
Commit 84f5c2908 forgot to consider the possibility that
EnsurePortalSnapshotExists could run inside a subtransaction with
lifespan shorter than the Portal's. In that case, the new active
snapshot would be popped at the end of the subtransaction, leaving
a dangling pointer in the Portal, with mayhem ensuing.
To fix, make sure the ActiveSnapshot stack entry is marked with
the same subtransaction nesting level as the associated Portal.
It's certainly safe to do so since we won't be here at all unless
the stack is empty; hence we can't create an out-of-order stack.
Let's also apply this logic in the case where PortalRunUtility
sets portalSnapshot, just to be sure that path can't cause similar
problems. It's slightly less clear that that path can't create
an out-of-order stack, so add an assertion guarding it.
Report and patch by Bertrand Drouvot (with kibitzing by me).
Back-patch to v11, like the previous commit.
Discussion: https://postgr.es/m/ff82b8c5-77f4-3fe7-6028-fcf3303e82dd@amazon.com
The code inconsistently used "statistic object" or "statistics" where
the correct term, as discussed, is actually "statistics object". This
improves the state of the code to be more consistent.
While on it, fix an incorrect error message introduced in a4d75c8. This
error should never happen, as the code states, but it would be
misleading.
Author: Justin Pryzby
Reviewed-by: Álvaro Herrera, Michael Paquier
Discussion: https://postgr.es/m/20210924215827.GS831@telsasoft.com
Backpatch-through: 14
Splitting the time field into days and microseconds is pretty
useless when we're just going to recombine those values.
It's unclear if anyone will notice the speedup in real-world
cases, but a cycle shaved is a cycle earned.
Discussion: https://postgr.es/m/2629129.1632675713@sss.pgh.pa.us
This runtime-computed GUC shows the number of huge pages required
for the server's main shared memory area, taking advantage of the
work done in 0c39c29 and 0bd305e. This is useful for users to estimate
the amount of huge pages required for a server as it becomes possible to
do an estimation without having to start the server and potentially
allocate a large chunk of shared memory.
The number of huge pages is calculated based on the existing GUC
huge_page_size if set, or by using the system's default by looking at
/proc/meminfo on Linux. There is nothing new here as this commit reuses
the existing calculation methods, and just exposes this information
directly to the user. The routine calculating the huge page size is
refactored to limit the number of files with platform-specific flags.
This new GUC's name was the most popular choice based on the discussion
done. This is only supported on Linux.
I have taken the time to test the change on Linux, Windows and MacOS,
though for the last two ones large pages are not supported. The first
one calculates correctly the number of pages depending on the existing
GUC huge_page_size or the system's default.
Thanks to Andres Freund, Robert Haas, Kyotaro Horiguchi, Tom Lane,
Justin Pryzby (and anybody forgotten here) for the discussion.
Author: Nathan Bossart
Discussion: https://postgr.es/m/F2772387-CE0F-46BF-B5F1-CC55516EB885@amazon.com
The rewriter transformation for SEARCH BREADTH FIRST produces a
FieldSelect on a Var of type RECORD, where the Var references the
recursive union's worktable output. EXPLAIN VERBOSE failed to handle
this case, because it only expected such Vars to appear in CteScans
not WorkTableScans. Fix that, and add some test cases exercising
EXPLAIN on SEARCH and CYCLE queries.
In principle this oversight is an old bug, but it seems that the
case is unreachable without SEARCH BREADTH FIRST, because the
parser fails when attempting to create such a reference manually.
So for today I'll just patch HEAD/v14. Someday we might find that
the code portion of this patch needs to be back-patched further.
Per report from Atsushi Torikoshi.
Discussion: https://postgr.es/m/5bafa66ad529e11860339565c9e7c166@oss.nttdata.com
Session statistics, as introduced by 960869da08, had several shortcomings:
- an additional GetCurrentTimestamp() call that also impaired the accuracy of
the data collected
This can be avoided by passing the current timestamp we already have in
pgstat_report_stat().
- an additional statistics UDP packet sent every 500ms
This is solved by adding the new statistics to PgStat_MsgTabstat.
This is conceptually ugly, because session statistics are not
table statistics. But the struct already contains data unrelated
to tables, so there is not much damage done.
Connection and disconnection are reported in separate messages, which
reduces the number of additional messages to two messages per session and a
slight increase in PgStat_MsgTabstat size (but the same number of table
stats fit).
- Session time computation could overflow on systems where long is 32 bit.
Reported-By: Andres Freund <andres@anarazel.de>
Author: Andres Freund <andres@anarazel.de>
Author: Laurenz Albe <laurenz.albe@cybertec.at>
Discussion: https://postgr.es/m/20210801205501.nyxzxoelqoo4x2qc%40alap3.anarazel.de
Backpatch: 14-, where the feature was introduced.
Until now, the -C option of postgres was handled before a small subset
of GUCs computed at runtime are initialized, leading to incorrect
results as GUC machinery would fall back to default values for such
parameters.
For example, data_checksums could report "off" for a cluster as the
control file is not loaded yet. Or wal_segment_size would show a
segment size at 16MB even if initdb --wal-segsize used something else.
Worse, the command would fail to properly report the recently-introduced
shared_memory, that requires to load shared_preload_libraries as these
could ask for a chunk of shared memory.
Support for runtime GUCs comes with a limitation, as the operation is
now allowed on a running server. One notable reason for this is that
_PG_init() functions of loadable libraries are called before all
runtime-computed GUCs are initialized, and this is not guaranteed to be
safe to do on running servers. For the case of shared_memory_size,
where we want to know how much memory would be used without allocating
it, this limitation is fine. Another case where this will help is for
huge pages, with the introduction of a different GUC to evaluate the
amount of huge pages required for a server before starting it, without
having to allocate large chunks of memory.
This feature is controlled with a new GUC flag, and four parameters are
classified as runtime-computed as of this change:
- data_checksums
- shared_memory_size
- data_directory_mode
- wal_segment_size
Some TAP tests are added to provide some coverage here, using
data_checksums in the tests of pg_checksums.
Per discussion with Andres Freund, Justin Pryzby, Magnus Hagander and
more.
Author: Nathan Bossart
Discussion: https://postgr.es/m/F2772387-CE0F-46BF-B5F1-CC55516EB885@amazon.com
Up to now the size of a query's rangetable has been limited by the
constants INNER_VAR et al, which mustn't be equal to any real
rangetable index. 65000 doubtless seemed like enough for anybody,
and it still is orders of magnitude larger than the number of joins
we can realistically handle. However, we need a rangetable entry
for each child partition that is (or might be) processed by a query.
Queries with a few thousand partitions are getting more realistic,
so that the day when that limit becomes a problem is in sight,
even if it's not here yet. Hence, let's raise the limit.
Rather than just increase the values of INNER_VAR et al, this patch
adopts the approach of making them small negative values, so that
rangetables could theoretically become as long as INT_MAX.
The bulk of the patch is concerned with changing Var.varno and some
related variables from "Index" (unsigned int) to plain "int". This
is basically cosmetic, with little actual effect other than to help
debuggers print their values nicely. As such, I've only bothered
with changing places that could actually see INNER_VAR et al, which
the parser and most of the planner don't. We do have to be careful
in places that are performing less/greater comparisons on varnos,
but there are very few such places, other than the IS_SPECIAL_VARNO
macro itself.
A notable side effect of this patch is that while it used to be
possible to add INNER_VAR et al to a Bitmapset, that will now
draw an error. I don't see any likelihood that it wouldn't be a
bug to include these fake varnos in a bitmapset of real varnos,
so I think this is all to the good.
Although this touches outfuncs/readfuncs, I don't think a catversion
bump is required, since stored rules would never contain Vars
with these fake varnos.
Andrey Lepikhov and Tom Lane, after a suggestion by Peter Eisentraut
Discussion: https://postgr.es/m/43c7f2f5-1e27-27aa-8c65-c91859d15190@postgrespro.ru
All the types supported were listed directly in the README, but it was
very outdated. Rather than listing all the types supported in the
README, this commit adds a reference to look at ResourceOwnerData in
resowner.c to get this information.
The order of the paragraphs is reworked a bit for clarity.
Author: Amit Langote
Discussion: https://postgr.es/m/CA+HiwqHtfT9z=4H5+F7DOy0OyNHAaVwuRcakt9b2t2uADOaiag@mail.gmail.com
The previous protocol expected a set of matching characters to check if
a message sent was the last one or not, that changed depending on the
destination wanted:
- 't' and 'f' tracked the last message of a log sent to stderr.
- 'T' and 'F' tracked the last message of a log sent to csvlog.
This could be extended with more characters when introducing new
destinations, but using a bitmask is much more elegant. This commit
changes the protocol so as a bitmask is used in the header of a log
chunk message sent to the syslogger, with the following options
available for now:
- log_destination as stderr.
- log_destination as csvlog.
- if a message is the last chunk of a message.
Sehrope found this issue in a patch set to introduce JSON as an option
for log_destination, but his patch made the size of the protocol header
larger. This commit keeps the same size as the original, and adapts the
protocol as wanted.
Thanks also to Andrew Dunstan and Greg Stark for the discussion.
Author: Michael Paquier, Sehrope Sarkuni
Discussion: https://postgr.es/m/CAH7T-aqswBM6JWe4pDehi1uOiufqe06DJWaU5=X7dDLyqUExHg@mail.gmail.com
The Value node struct is a weird construct. It is its own node type,
but most of the time, it actually has a node type of Integer, Float,
String, or BitString. As a consequence, the struct name and the node
type don't match most of the time, and so it has to be treated
specially a lot. There doesn't seem to be any value in the special
construct. There is very little code that wants to accept all Value
variants but nothing else (and even if it did, this doesn't provide
any convenient way to check it), and most code wants either just one
particular node type (usually String), or it accepts a broader set of
node types besides just Value.
This change removes the Value struct and node type and replaces them
by separate Integer, Float, String, and BitString node types that are
proper node types and structs of their own and behave mostly like
normal node types.
Also, this removes the T_Null node tag, which was previously also a
possible variant of Value but wasn't actually used outside of the
Value contained in A_Const. Replace that by an isnull field in
A_Const.
Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/5ba6bc5b-3f95-04f2-2419-f8ddb4c046fb@enterprisedb.com
Commit 01e658fa74 added hash support for row types. This also added
support for hashing anonymous record types, using the same approach
that the type cache uses for comparison support for record types: It
just reports that it works, but it might fail at run time if a
component type doesn't actually support the operation. We get away
with that for comparison because most types support that. But some
types don't support hashing, so the current state can result in
failures at run time where the planner chooses hashing over sorting,
whereas that previously worked if only sorting was an option.
We do, however, want the record hashing support for path tracking in
recursive unions, and the SEARCH and CYCLE clauses built on that. In
that case, hashing is the only plan option. So enable that, this
commit implements the following approach: The type cache does not
report that hashing is available for the record type. This undoes
that part of 01e658fa74. Instead, callers that require hashing no
matter what can override that result themselves. This patch only
touches the callers to make the aforementioned recursive query cases
work, namely the parse analysis of unions, as well as the hash_array()
function.
Reported-by: Sait Talha Nisanci <sait.nisanci@microsoft.com>
Bug: #17158
Discussion: https://www.postgresql.org/message-id/flat/17158-8a2ba823982537a4%40postgresql.org
This runtime-computed GUC shows the size of the server's main shared
memory area, taking into account the amount of shared memory allocated
by extensions as this is calculated after processing
shared_preload_libraries.
Author: Nathan Bossart
Discussion: https://postgr.es/m/F2772387-CE0F-46BF-B5F1-CC55516EB885@amazon.com
All the code paths simplified here were already using a boolean or used
an expression that led to zero or one, making the extra bits
unnecessary.
Author: Justin Pryzby
Reviewed-by: Tom Lane, Michael Paquier, Peter Smith
Discussion: https://postgr.es/m/20210428182936.GE27406@telsasoft.com
Historically, timetz_zone() has used time(NULL) as the reference point
for deciding whether DST is active. That means its result can change
intra-statement, requiring it to be marked VOLATILE (cf. 35979e6c3).
But that definition is pretty inconsistent with the way we deal with
timestamps elsewhere. Let's make it use the transaction start time
("now()") as the reference point instead. That lets it be marked
STABLE, and also saves a kernel call per invocation.
While at it, remove the function's use of pg_time_t and pg_localtime.
Those are inconsistent with the other code in this area, which indeed
created a bug: timetz_zone() delivered completely wrong answers if
the zone was specified by a dynamic TZ abbreviation. (We need to do
something about that in the back branches, but the fix will look
different from this.)
Aleksander Alekseev and Tom Lane
Discussion: https://postgr.es/m/CAJ7c6TOMG8zSNEZtCn5SPe+cCk3Lfxb71ZaQwT2F4T7PJ_t=KA@mail.gmail.com
Use one fileset for the entire worker lifetime instead of using
separate filesets for each streaming transaction. Now, the
changes/subxacts files for every streaming transaction will be
created under the same fileset and the files will be deleted
after the transaction is completed.
This patch extends the BufFileOpenFileSet and BufFileDeleteFileSet
APIs to allow users to specify whether to give an error on missing
files.
Author: Dilip Kumar, based on suggestion by Thomas Munro
Reviewed-by: Hou Zhijie, Masahiko Sawada, Amit Kapila
Discussion: https://postgr.es/m/E1mCC6U-0004Ik-Fs@gemulon.postgresql.org
unpack_sql_state() has been introduced in d46bc44 to refactor the
unpacking of a SQLSTATE into a string, but it forgot one code path when
sending error reports to clients that could make use of it. This
changes the code to also use unpack_sql_state() there, simplifying a bit
the code.
Author: Peter Smith
Discussion: https://postgr.es/m/CAHut+PuYituuD1-VVZUNcmCQuc3ZzZMPoO57POgm8tnXOkwJAA@mail.gmail.com
The code printing expressions for extended statistics doubled the
parens, producing results like ((a+1)), which is unnecessary and not
consistent with how we print expressions elsewhere.
Fixed by tweaking the code to produce just a single set of parens.
Reported by Mark Dilger, fix by me. Backpatch to 14, where support for
extended statistics on expressions was added.
Reported-by: Mark Dilger
Discussion: https://postgr.es/m/20210122040101.GF27167%40telsasoft.com
When starting to use a query parsetree loaded from the catalogs,
we must begin by applying AcquireRewriteLocks(), to obtain the same
relation locks that the parser would have gotten if the query were
entered interactively, and to do some other cleanup such as dealing
with later-dropped columns. New-style SQL functions are just as
subject to this rule as other stored parsetrees; however, of the
places dealing with such functions, only init_sql_fcache had gotten
the memo. In particular, if we successfully inlined a new-style
set-returning SQL function that contained any relation references,
we'd either get an assertion failure or attempt to use those
relation(s) sans locks.
I also added AcquireRewriteLocks calls to fmgr_sql_validator and
print_function_sqlbody. Desultory experiments didn't demonstrate any
failures in those, but I suspect that I just didn't try hard enough.
Certainly we don't expect nearby code paths to operate without locks.
On the same logic of it-ought-to-have-the-same-effects-as-the-old-code,
call pg_rewrite_query() in fmgr_sql_validator, too. It's possible
that neither code path there needs to bother with rewriting, but
doing the analysis to prove that is beyond my goals for today.
Per bug #17161 from Alexander Lakhin.
Discussion: https://postgr.es/m/17161-048a1cdff8422800@postgresql.org
Move fileset related implementation out of sharedfileset.c to allow its
usage by backends that don't want to share filesets among different
processes. After this split, fileset infrastructure is used by both
sharedfileset.c and worker.c for the named temporary files that survive
across transactions.
Author: Dilip Kumar, based on suggestion by Andres Freund
Reviewed-by: Hou Zhijie, Masahiko Sawada, Amit Kapila
Discussion: https://postgr.es/m/E1mCC6U-0004Ik-Fs@gemulon.postgresql.org
The distance in phrase operator must be an integer value between zero
and MAXENTRYPOS inclusive. But previously the error message about
its valid value included the information about its upper limit
but not lower limit (i.e., zero). This commit improves the error message
so that it also includes the information about its lower limit.
Back-patch to v9.6 where full-text phrase search was supported.
Author: Kyotaro Horiguchi
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/20210819.170315.1413060634876301811.horikyota.ntt@gmail.com
Previously log messages late during shutdown could end up using either another
backend's PgBackendStatus (multi user) or segfault (single user) because
pgstat_get_my_query_id()'s check for !MyBEEntry didn't filter out use after
pgstat_beshutdown_hook().
This became a bug in 4f0b0966c8, but was a bit fishy before. But given
there's no known problematic cases before 14, it doesn't seem worth
backpatching further.
Also fixes a wrong filename in a comment, introduced in e1025044.
Reported-By: Andres Freund <andres@anarazel.de>
Reviewed-By: Julien Rouhaud <rjuju123@gmail.com>
Discussion: https://postgr.es/m/Julien Rouhaud <rjuju123@gmail.com>
Backpatch: 14-
This is a combined revert of the following commits:
- c3826f8, a refactoring piece that moved the hex decoding code to
src/common/. This code was cleaned up by aef8948, as it originally
included no overflow checks in the same way as the base64 routines in
src/common/ used by SCRAM, making it unsafe for its purpose.
- aef8948, a more advanced refactoring of the hex encoding/decoding code
to src/common/ that added sanity checks on the result buffer for hex
decoding and encoding. As reported by Hans Buschmann, those overflow
checks are expensive, and it is possible to see a performance drop in
the decoding/encoding of bytea or LOs the longer they are. Simple SQLs
working on large bytea values show a clear difference in perf profile.
- ccf4e27, a cleanup made possible by aef8948.
The reverts of all those commits bring back the performance of hex
decoding and encoding back to what it was in ~13. Fow now and
post-beta3, this is the simplest option.
Reported-by: Hans Buschmann
Discussion: https://postgr.es/m/1629039545467.80333@nidsa.net
Backpatch-through: 14
The existing data structures in inval.c are fairly inefficient for
the common case of a command or subtransaction that registers a small
number of cache invalidation events. While this doesn't matter if we
commit right away, it can build up to a lot of bloat in a transaction
that contains many DDL operations. By making a few more assumptions
about the expected use-case, we can switch to a representation using
densely-packed arrays. Although this eliminates some data-copying,
it doesn't seem to make much difference time-wise. But the space
consumption decreases substantially.
Patch by me; thanks to Nathan Bossart for review.
Discussion: https://postgr.es/m/2380555.1622395376@sss.pgh.pa.us
If the replacement string doesn't contain \1...\9, then we don't
need sub-match locations, so we can use the REG_NOSUB optimization
here too. There's already a pre-scan of the replacement string
to look for backslashes, so extend that to check for digits, and
refactor to allow that to happen before we compile the regexp.
While at it, try to speed up the pre-scan by using memchr() instead
of a handwritten loop. It's likely that this is lost in the noise
compared to the regexp processing proper, but maybe not. In any
case, this coding is shorter.
Also, add some test cases to improve the poor coverage of
appendStringInfoRegexpSubstr().
Discussion: https://postgr.es/m/3534632.1628536485@sss.pgh.pa.us
Identifying the precise match locations for parenthesized subexpressions
is a fairly expensive task given the way our regexp engine works, both
at regexp compile time (where we must create an optimized NFA for each
parenthesized subexpression) and at runtime (where determining exact
match locations requires laborious search).
Up to now we've made little attempt to optimize this situation. This
patch identifies cases where we know at compile time that we won't
need to know subexpression match locations, and teaches the regexp
compiler to not bother creating per-subexpression regexps for
parenthesis pairs that are not referenced by backrefs elsewhere in
the regexp. (To preserve semantics, we obviously still have to
pin down the match locations of backref references.) Users could
have obtained the same results before this by being careful to
write "non capturing" parentheses wherever possible, but few people
bother with that.
Discussion: https://postgr.es/m/2219936.1628115334@sss.pgh.pa.us
As reported by a few OSX buildfarm animals there exist at least one path where
temporary files exist during AtProcExit_Files() processing. As temporary file
cleanup causes pgstat reporting, the assertions added in ee3f8d3d3a caused
failures.
This is not an OSX specific issue, we were just lucky that timing on OSX
reliably triggered the problem. The known way to cause this is a FATAL error
during perform_base_backup() with a MANIFEST used - adding an elog(FATAL)
after InitializeBackupManifest() reliably reproduces the problem in isolation.
The problem is that the temporary file created in InitializeBackupManifest()
is not cleaned up via resource owner cleanup as WalSndResourceCleanup()
currently is only used for non-FATAL errors. That then allows to reach
AtProcExit_Files() with existing temporary files, causing the assertion
failure.
To fix this problem, move temporary file cleanup to a before_shmem_exit() hook
and add assertions ensuring that no temporary files are created before / after
temporary file management has been initialized / shut down. The cleanest way
to do so seems to be to split fd.c initialization into two, one for plain file
access and one for temporary file access.
Right now there's no need to perform further fd.c cleanup during process exit,
so I just renamed AtProcExit_Files() to BeforeShmemExit_Files(). Alternatively
we could perform another pass through the files to check that no temporary
files exist, but the added assertions seem to provide enough protection
against that.
It might turn out that the assertions added in ee3f8d3d3a will cause too much
noise - in that case we'll have to downgrade them to a WARNING, at least
temporarily.
This commit is not necessarily the best approach to address this issue, but it
should resolve the buildfarm failures. We can revise later.
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210807190131.2bm24acbebl4wl6i@alap3.anarazel.de
Previously pgstat_initialize() was called in InitPostgres() and
AuxiliaryProcessMain(). As it turns out there was at least one case where we
reported stats before pgstat_initialize() was called, see
AutoVacWorkerMain()'s intentionally early call to pgstat_report_autovac().
This turns out to not be a problem with the current pgstat implementation as
pgstat_initialize() only registers a shutdown callback. But in the shared
memory based stats implementation we are working towards pgstat_initialize()
has to do more work.
After b406478b87 BaseInit() is a central place where initialization shared by
normal backends and auxiliary backends can be put. Obviously BaseInit() is
called before InitPostgres() registers ShutdownPostgres. Previously
ShutdownPostgres was the first before_shmem_exit callback, now that's commonly
pgstats. That should be fine.
Previously pgstat_initialize() was not called in bootstrap mode, but there
does not appear to be a need for that. It's now done unconditionally.
To detect future issues like this, assertions are added to a few places
verifying that the pgstat subsystem is initialized and not yet shut down.
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210405092914.mmxqe7j56lsjfsej@alap3.anarazel.de
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de
Formerly, the numeric code tested whether an integer value of a larger
type would fit in a smaller type by casting it to the smaller type and
then testing if the reverse conversion produced the original value.
That's perfectly fine, except that it caused a test failure on
buildfarm animal castoroides, most likely due to a compiler bug.
Instead, do these tests by comparing against PG_INT16/32_MIN/MAX. That
matches existing code in other places, such as int84(), which is more
widely tested, and so is less likely to go wrong.
While at it, add regression tests covering the numeric-to-int8/4/2
conversions, and adjust the recently added tests to the style of
434ddfb79a (on the v11 branch) to make failures easier to diagnose.
Per buildfarm via Tom Lane, reviewed by Tom Lane.
Discussion: https://postgr.es/m/2394813.1628179479%40sss.pgh.pa.us
For EXEC_BACKEND InitProcess()/InitAuxiliaryProcess() needs to have been
called well before we call BaseInit(), as SubPostmasterMain() needs LWLocks to
work. Having the order of initialization differ between platforms makes it
unnecessarily hard to understand the system and to add initialization points
for new subsystems without a lot of duplication.
To be able to change the order, BaseInit() cannot trigger
CreateSharedMemoryAndSemaphores() anymore - obviously that needs to have
happened before we can call InitProcess(). It seems cleaner to create shared
memory explicitly in single user/bootstrap mode anyway.
After this change the separation of bufmgr initialization into
InitBufferPoolAccess() / InitBufferPoolBackend() is not meaningful anymore so
the latter is removed.
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de
For one, the existing location lead to somewhat awkward code in main(). For
another, the new location is easier to understand anyway.
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de
This fixes a long-standing bug when using to_char() to format a
numeric value in scientific notation -- if the value's exponent is
less than -NUMERIC_MAX_DISPLAY_SCALE-1 (-1001), it produced a
division-by-zero error.
The reason for this error was that get_str_from_var_sci() divides its
input by 10^exp, which it produced using power_var_int(). However, the
underflow test in power_var_int() causes it to return zero if the
result scale is too small. That's not a problem for power_var_int()'s
only other caller, power_var(), since that limits the rscale to 1000,
but in get_str_from_var_sci() the exponent can be much smaller,
requiring a much larger rscale. Fix by introducing a new function to
compute 10^exp directly, with no rscale limit. This also allows 10^exp
to be computed more efficiently, without any numeric multiplication,
division or rounding.
Discussion: https://postgr.es/m/CAEZATCWhojfH4whaqgUKBe8D5jNHB8ytzemL-PnRx+KCTyMXmg@mail.gmail.com
These have been unrelated since bgwriter and checkpointer were split into two
processes in 806a2aee37. As there several pending patches (shared memory
stats, extending the set of tracked IO / buffer statistics) that are made a
bit more awkward by the grouping, split them. Done separately to make
reviewing easier.
This does *not* change the contents of pg_stat_bgwriter or move fields out of
bgwriter/checkpointer stats that arguably do not belong in either. However
pgstat_fetch_global() was renamed and split into
pgstat_fetch_stat_checkpointer() and pgstat_fetch_stat_bgwriter().
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210405092914.mmxqe7j56lsjfsej@alap3.anarazel.de
This patch adds new functions regexp_count(), regexp_instr(),
regexp_like(), and regexp_substr(), and extends regexp_replace()
with some new optional arguments. All these functions follow
the definitions used in Oracle, although there are small differences
in the regexp language due to using our own regexp engine -- most
notably, that the default newline-matching behavior is different.
Similar functions appear in DB2 and elsewhere, too. Aside from
easing portability, these functions are easier to use for certain
tasks than our existing regexp_match[es] functions.
Gilles Darold, heavily revised by me
Discussion: https://postgr.es/m/fc160ee0-c843-b024-29bb-97b5da61971f@darold.net
This fixes a couple of related problems that arise when raising
numbers to very large powers.
Firstly, when raising a negative number to a very large integer power,
the result should be well-defined, but the previous code would only
cope if the exponent was small enough to go through power_var_int().
Otherwise it would throw an internal error, attempting to take the
logarithm of a negative number. Fix this by adding suitable handling
to the general case in power_var() to cope with negative bases,
checking for integer powers there.
Next, when raising a (positive or negative) number whose absolute
value is slightly less than 1 to a very large power, the result should
approach zero as the power is increased. However, in some cases, for
sufficiently large powers, this would lose all precision and return 1
instead of 0. This was due to the way that the local_rscale was being
calculated for the final full-precision calculation:
local_rscale = rscale + (int) val - ln_dweight + 8
The first two terms on the right hand side are meant to give the
number of significant digits required in the result ("val" being the
estimated result weight). However, this failed to account for the fact
that rscale is clipped to a maximum of NUMERIC_MAX_DISPLAY_SCALE
(1000), and the result weight might be less then -1000, causing their
sum to be negative, leading to a loss of precision. Fix this by
forcing the number of significant digits calculated to be nonnegative.
It's OK for it to be zero (when the result weight is less than -1000),
since the local_rscale value then includes a few extra digits to
ensure an accurate result.
Finally, add additional underflow checks to exp_var() and power_var(),
so that they consistently return zero for cases like this where the
result is indistinguishable from zero. Some paths through this code
already returned zero in such cases, but others were throwing overflow
errors.
Dean Rasheed, reviewed by Yugo Nagata.
Discussion: http://postgr.es/m/CAEZATCW6Dvq7+3wN3tt5jLj-FyOcUgT5xNoOqce5=6Su0bCR0w@mail.gmail.com
This changes the behavior of examining the pg_file_settings view after
changing a config option that requires restart. The user needs to know
that any change of such options does not take effect until a restart,
and this worked correctly if the line is edited without removing it.
However, for the case where the line is removed altogether, the flag
doesn't get set, because a flag was only set in set_config_option, but
that's not called for lines removed. Repair.
(Ref.: commits 62d16c7fc5 and a486e35706)
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/202107262302.xsfdfc5sb7sh@alvherre.pgsql
The error messages using the word "non-negative" are confusing
because it's ambiguous about whether it accepts zero or not.
This commit improves those error messages by replacing it with
less ambiguous word like "greater than zero" or
"greater than or equal to zero".
Also this commit added the note about the word "non-negative" to
the error message style guide, to help writing the new error messages.
When postgres_fdw option fetch_size was set to zero, previously
the error message "fetch_size requires a non-negative integer value"
was reported. This error message was outright buggy. Therefore
back-patch to all supported versions where such buggy error message
could be thrown.
Reported-by: Hou Zhijie
Author: Bharath Rupireddy
Reviewed-by: Kyotaro Horiguchi, Fujii Masao
Discussion: https://postgr.es/m/OS0PR01MB5716415335A06B489F1B3A8194569@OS0PR01MB5716.jpnprd01.prod.outlook.com
This patch causes EXPLAIN output to refer to objects that are in
the current session's temp schema with the "pg_temp" schema alias
rather than that schema's actual name. This is useful for our own
testing purposes since it will stabilize EXPLAIN VERBOSE output
for such cases, allowing us to use that in regression tests.
It should be less confusing for end users too.
Since ruleutils.c needs to change behavior for this, the change
also leaks into a few other users of ruleutils.c, for example
pg_get_viewdef(). AFAICS that won't cause any problems.
We did find that aggressively trying to change this behavior
across-the-board would cause issues, but as long as "pg_temp"
only appears within generated SQL text, I think it'll be fine.
Along the way, make get_namespace_name_or_temp conform to the
same API as get_namespace_name, ie that it returns a palloc'd
string or NULL. The current behavior hasn't caused any bugs
since no callers attempt to pfree the result, but if it gets
more widespread usage that could become a problem.
Amul Sul, reviewed and extended by me
Discussion: https://postgr.es/m/CAAJ_b97W=QaGmag9AhWNbmx3uEYsNkXWL+OVW1_E1D3BtgWvtw@mail.gmail.com
Formerly, when specifying NUMERIC(precision, scale), the scale had to
be in the range [0, precision], which was per SQL spec. This commit
extends the range of allowed scales to [-1000, 1000], independent of
the precision (whose valid range remains [1, 1000]).
A negative scale implies rounding before the decimal point. For
example, a column might be declared with a scale of -3 to round values
to the nearest thousand. Note that the display scale remains
non-negative, so in this case the display scale will be zero, and all
digits before the decimal point will be displayed.
A scale greater than the precision supports fractional values with
zeros immediately after the decimal point.
Take the opportunity to tidy up the code that packs, unpacks and
validates the contents of a typmod integer, encapsulating it in a
small set of new inline functions.
Bump the catversion because the allowed contents of atttypmod have
changed for numeric columns. This isn't a change that requires a
re-initdb, but negative scale values in the typmod would confuse old
backends.
Dean Rasheed, with additional improvements by Tom Lane. Reviewed by
Tom Lane.
Discussion: https://postgr.es/m/CAEZATCWdNLgpKihmURF8nfofP0RFtAKJ7ktY6GcZOPnMfUoRqA@mail.gmail.com
In postgresql.conf, memory and file size GUCs can be specified with "B"
(bytes) as of b06d8e58b. Likewise, time GUCs can be specified with "us"
(microseconds) as of caf626b2c. Update postgres.conf.sample to reflect
that fact.
Pavel Luzanov
Backpatch to v12, which is the earliest version that allows both of
these units. A separate commit will document the "B" case for v11.
Discussion: https://www.postgresql.org/message-id/flat/f10d16fc-8fa0-1b3c-7371-cb3a35a13b7a%40postgrespro.ru
It has been spotted that multiranges lack of ability to decompose them into
individual ranges. Subscription and proper expanded object representation
require substantial work, and it's too late for v14. This commit
provides the implementation of unnest(multirange), which is quite trivial.
unnest(multirange) is defined as a polymorphic procedure.
Catversion is bumped.
Reported-by: Jonathan S. Katz
Discussion: https://postgr.es/m/flat/60258efe-bd7e-4886-82e1-196e0cac5433%40postgresql.org
Author: Alexander Korotkov
Reviewed-by: Justin Pryzby, Jonathan S. Katz, Zhihong Yu, Tom Lane
Reviewed-by: Alvaro Herrera
Commit 0563a3a8b changed how partition constraints were generated such
that this function no longer computes the mapping of parent attnos to
child attnos.
This is an external function that extensions could use, so this is
potentially a breaking change. No external callers are known, however,
and this will make it simpler to write such callers in the future.
Author: Hou Zhijie
Reviewed-by: David Rowley, Michael Paquier, Soumyadeep Chakraborty
Discussion: https://www.postgresql.org/message-id/flat/OS0PR01MB5716A75A45BE46101A1B489894379@OS0PR01MB5716.jpnprd01.prod.outlook.com
"Result Cache" was never a great name for this node, but nobody managed
to come up with another name that anyone liked enough. That was until
David Johnston mentioned "Node Memoization", which Tom Lane revised to
just "Memoize". People seem to like "Memoize", so let's do the rename.
Reviewed-by: Justin Pryzby
Discussion: https://postgr.es/m/20210708165145.GG1176@momjian.us
Backpatch-through: 14, where Result Cache was introduced
41469253e went to the trouble of removing a theoretical bug from
free_sort_tuple by checking if the tuple was NULL before freeing it. Let's
make this a little more robust by also setting the tuple to NULL so that
should we be called again we won't end up doing a pfree on the already
pfree'd tuple. Per advice from Tom Lane.
Discussion: https://postgr.es/m/3188192.1626136953@sss.pgh.pa.us
Backpatch-through: 9.6, same as 41469253e
This fixes a theoretical bug in tuplesort.c which, if a bounded sort was
used in combination with a byval Datum sort (tuplesort_begin_datum), when
switching the sort to a bounded heap in make_bounded_heap(), we'd call
free_sort_tuple(). The problem was that when sorting Datums of a byval
type, the tuple is NULL and free_sort_tuple() would free the memory for it
regardless of that. This would result in a crash.
Here we fix that simply by adding a check to see if the tuple is NULL
before trying to disassociate and free any memory belonging to it.
The reason this bug is only theoretical is that nowhere in the current
code base do we do tuplesort_set_bound() when performing a Datum sort.
However, let's backpatch a fix for this as if any extension uses the code
in this way then it's likely to cause problems.
Author: Ronan Dunklau
Discussion: https://postgr.es/m/CAApHDvpdoqNC5FjDb3KUTSMs5dg6f+XxH4Bg_dVcLi8UYAG3EQ@mail.gmail.com
Backpatch-through: 9.6, oldest supported version
If an error occurred in the wrong place, it was possible to leave an
unintialized entry in the hash table, leading to a crash. Fixed.
Also, be more careful about the order of operations so that an
allocation error doesn't leak memory in CacheMemoryContext or
unnecessarily advance NextRecordTypmod.
Backpatch through version 11. Earlier versions (prior to 35ea75632a)
do not exhibit the problem, because an uninitialized hash entry
contains a valid empty list.
Author: Sait Talha Nisanci <Sait.Nisanci@microsoft.com>
Reviewed-by: Andres Freund
Discussion: https://postgr.es/m/HE1PR8303MB009069D476225B9A9E194B8891779@HE1PR8303MB0090.EURPRD83.prod.outlook.com
Backpatch-through: 11
This fixes an overflow error when using the numeric * operator if the
result has more than 16383 digits after the decimal point by rounding
the result. Overflow errors should only occur if the result has too
many digits *before* the decimal point.
Discussion: https://postgr.es/m/CAEZATCUmeFWCrq2dNzZpRj5+6LfN85jYiDoqm+ucSXhb9U2TbA@mail.gmail.com
There was talk about adding units all the way up to yottabytes but it
seems quite far-fetched that anyone would need those. Since such large
units are not exactly commonplace, it seems unlikely that having
pg_size_pretty outputting unit any larger than petabytes would actually be
helpful to anyone.
Since petabytes are on the horizon, let's just add those only. Maybe one
day we'll get to add additional units, but it will likely be a while
before we'll need to think beyond petabytes in regards to the size of a
database.
Author: David Christensen
Discussion: https://postgr.es/m/CAOxo6XKmHc_WZip-x5QwaOqFEiCq_SVD0B7sbTZQk+qqcn2qaw@mail.gmail.com
We've grown 2 versions of pg_size_pretty over the years, one for BIGINT
and one for NUMERIC. Both should output the same, but keeping them in
sync is harder than needed due to neither function sharing a source of
truth about which units to use and how to transition to the next largest
unit.
Here we add a static array which defines the units that we recognize and
have both pg_size_pretty and pg_size_pretty_numeric use it. This will
make adding any units in the future a very simple task.
The table contains all information required to allow us to also modify
pg_size_bytes to use the lookup table, so adjust that too.
There are no behavioral changes here.
Author: David Rowley
Reviewed-by: Dean Rasheed, Tom Lane, David Christensen
Discussion: https://postgr.es/m/CAApHDvru1F7qsEVL-iOHeezJ+5WVxXnyD_Jo9nht+Eh85ekK-Q@mail.gmail.com
Due to how pg_size_pretty(bigint) was implemented, it's possible that when
given a negative number of bytes that the returning value would not match
the equivalent positive return value when given the equivalent positive
number of bytes. This was due to two separate issues.
1. The function used bit shifting to convert the number of bytes into
larger units. The rounding performed by bit shifting is not the same as
dividing. For example -3 >> 1 = -2, but -3 / 2 = -1. These two
operations are only equivalent with positive numbers.
2. The half_rounded() macro rounded towards positive infinity. This meant
that negative numbers rounded towards zero and positive numbers rounded
away from zero.
Here we fix#1 by dividing the values instead of bit shifting. We fix#2
by adjusting the half_rounded macro always to round away from zero.
Additionally, adjust the pg_size_pretty(numeric) function to be more
explicit that it's using division rather than bit shifting. A casual
observer might have believed bit shifting was used due to a static
function being named numeric_shift_right. However, that function was
calculating the divisor from the number of bits and performed division.
Here we make that more clear. This change is just cosmetic and does not
affect the return value of the numeric version of the function.
Here we also add a set of regression tests both versions of
pg_size_pretty() which test the values directly before and after the
function switches to the next unit.
This bug was introduced in 8a1fab36a. Prior to that negative values were
always displayed in bytes.
Author: Dean Rasheed, David Rowley
Discussion: https://postgr.es/m/CAEZATCXnNW4HsmZnxhfezR5FuiGgp+mkY4AzcL5eRGO4fuadWg@mail.gmail.com
Backpatch-through: 9.6, where the bug was introduced.
Commit 03ffc4d6d added logic to bypass all caching behavior in
LookupOpclassInfo when CLOBBER_CACHE_ALWAYS is enabled. It doesn't
look like I stopped to think much about what that would cost, but
recent investigation shows that the cost is enormous: it roughly
doubles the time needed for cache-clobber test runs.
There does seem to be value in this behavior when trying to test
the opclass-cache loading logic itself, but for other purposes the
cost is excessive. Hence, let's back off to doing this only when
debug_invalidate_system_caches_always is at least 3; or in older
branches, when CLOBBER_CACHE_RECURSIVELY is defined.
While here, clean up some other minor issues in LookupOpclassInfo.
Re-order the code so we aren't left with broken cache entries (leading
to later core dumps) in the unlikely case that we suffer OOM while
trying to allocate space for a new entry. (That seems to be my
oversight in 03ffc4d6d.) Also, in >= v13, stop allocating one array
entry too many. That's evidently left over from sloppy reversion in
851b14b0c.
Back-patch to all supported branches, mainly to reduce the runtime
of cache-clobbering buildfarm animals.
Discussion: https://postgr.es/m/1370856.1625428625@sss.pgh.pa.us
Formerly various numeric aggregate functions supported parallel
aggregation by having each worker convert partial aggregate values to
Numeric and use numeric_send() as part of serializing their state.
That's problematic, since the range of Numeric is smaller than that of
NumericVar, so it's possible for it to overflow (on either side of the
decimal point) in cases that would succeed in non-parallel mode.
Fix by serializing NumericVars instead, to avoid the overflow risk and
ensure that parallel and non-parallel modes work the same.
A side benefit is that this improves the efficiency of the
serialization/deserialization code, which can make a noticeable
difference to performance with large numbers of parallel workers.
No back-patch due to risk from changing the binary format of the
aggregate serialization states, as well as lack of prior field
complaints and low probability of such overflows in practice.
Patch by me. Thanks to David Rowley for review and performance
testing, and Ranier Vilela for an additional suggestion.
Discussion: https://postgr.es/m/CAEZATCUmeFWCrq2dNzZpRj5+6LfN85jYiDoqm+ucSXhb9U2TbA@mail.gmail.com
This has the advantage to make a process more responsive when the
postmaster dies, even if the wait time was rather limited as there was
only a 50ms timeout here. Another advantage of this change is for
monitoring, as we gain a new wait event for the end-of-vacuum
truncation.
Author: Bharath Rupireddy
Reviewed-by: Aleksander Alekseev, Thomas Munro, Michael Paquier
Discussion: https://postgr.es/m/CALj2ACU4AdPCq6NLfcA-ZGwX7pPCK5FgEj-CAU0xCKzkASSy_A@mail.gmail.com
Several places were performing a tight loop to determine the first power
of 2 number that's > or >= the required memory. Instead of using a loop
for that, we can use pg_nextpower2_32 or pg_nextpower2_64. When we need a
power of 2 number equal to or greater than a given amount, we just pass
the amount to the nextpower2 function. When we need a power of 2 greater
than the amount, we just pass the amount + 1.
Additionally, in tsearch there were a couple of locations that were
performing a while loop when a simple "if" would have done. In both of
these locations only 1 item is being added, so the loop could only have
ever iterated once. Changing the loop into an if statement makes the code
very slightly more optimal as the condition is checked once rather than
twice.
There are quite a few remaining locations that increase the size of the
buffer in the following form:
while (reqsize >= buflen)
{
buflen *= 2;
buf = repalloc(buf, buflen);
}
These are not touched in this commit. repalloc will error out for sizes
larger than MaxAllocSize. Changing these to use pg_nextpower2_32 would
remove the chance of that error being raised. It's unclear from the code
if the sizes could ever become that large, so err on the side of caution.
Discussion: https://postgr.es/m/CAApHDvp=tns7RL4PH0ZR0M+M-YFLquK7218x=0B_zO+DbOma+w@mail.gmail.com
Reviewed-by: Zhihong Yu
* Fix enumeration of the multirange operators in calc_multirangesel() and
calc_multirangesel() switches.
* Add more regression tests for matching to empty ranges/multiranges.
Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/c5269c65-f967-77c5-ff7c-15e621c47f6a%40gmail.com
Author: Alexander Korotkov
Backpatch-through: 14, where multiranges were introduced
The logic is implemented so as there can be a choice in the compression
used when building a WAL record, and an extra per-record bit is used to
track down if a block is compressed with PGLZ, LZ4 or nothing.
wal_compression, the existing parameter, is changed to an enum with
support for the following backward-compatible values:
- "off", the default, to not use compression.
- "pglz" or "on", to compress FPWs with PGLZ.
- "lz4", the new mode, to compress FPWs with LZ4.
Benchmarking has showed that LZ4 outclasses easily PGLZ. ZSTD would be
also an interesting choice, but going just with LZ4 for now makes the
patch minimalistic as toast compression is already able to use LZ4, so
there is no need to worry about any build-related needs for this
implementation.
Author: Andrey Borodin, Justin Pryzby
Reviewed-by: Dilip Kumar, Michael Paquier
Discussion: https://postgr.es/m/3037310D-ECB7-4BF1-AF20-01C10BB33A33@yandex-team.ru
We were using RelationGetIndexList() to update the relation's replica
identity index but instead, we can directly use RelationGetReplicaIndex()
which uses the same functionality. This is a minor code readability
improvement.
Author: Japin Li
Reviewed-By: Takamichi Osumi, Amit Kapila
Discussion: https://postgr.es/m/4C99A862-69C8-431F-960A-81B1151F1B89@enterprisedb.com
The setting has no effect except during startup. It's still nice to be
able to change it dynamically, which is expected to be pretty useful to
an admin following crash recovery when restarting the cluster is not so
appealing.
Per discussions following commits 2941138e6 and 61752afb2.
Author: Justin Pryzby <pryzby@telsasoft.com>
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/20210529192321.GM2082%40telsasoft.com
The main goal of this option is to allow inspecting temporary files for
debugging purposes, so moving the parameter there is natural.
Oversight in cd91de0.
Reported-by: Justin Pryzby
Author: Euler Taveira
Discussion: https://postgr.es/m/20210612004347.GP16435@telsasoft.com
Contrary to the comment here, POSIX does not guarantee atomicity of a
read(), if another process calls write() concurrently. Or at least Linux
does not. Add locking to load_relmap_file() to avoid the race condition.
Fixes bug #17064. Thanks to Alexander Lakhin for the report and test case.
Backpatch-through: 9.6, all supported versions.
Discussion: https://www.postgresql.org/message-id/17064-bb0d7904ef72add3@postgresql.org
It has been spotted that multiranges lack of ability to decompose them into
individual ranges. Subscription and proper expanded object representation
require substantial work, and it's too late for v14. This commit
provides the implementation of unnest(multirange) and cast multirange as
an array of ranges, which is quite trivial.
unnest(multirange) is defined as a polymorphic procedure. The catalog
description of the cast underlying procedure is duplicated for each multirange
type because we don't have anyrangearray polymorphic type to use here.
Catversion is bumped.
Reported-by: Jonathan S. Katz
Discussion: https://postgr.es/m/flat/60258efe-bd7e-4886-82e1-196e0cac5433%40postgresql.org
Author: Alexander Korotkov
Reviewed-by: Justin Pryzby, Jonathan S. Katz, Zhihong Yu
Previously, a zero value for the relfilenode resulted in
a confusing error message about "unexpected duplicate".
This function returns NULL for other invalid relfilenode
values, so zero should be treated likewise.
It's been like this all along, so back-patch to all supported
branches.
Justin Pryzby
Discussion: https://postgr.es/m/20210612023324.GT16435@telsasoft.com
Commit 2453ea142 redefined pg_proc.proargtypes to include the types of
OUT parameters, for procedures only. While that had some advantages
for implementing the SQL-spec behavior of DROP PROCEDURE, it was pretty
disastrous from a number of other perspectives. Notably, since the
primary key of pg_proc is name + proargtypes, this made it possible to
have multiple procedures with identical names + input arguments and
differing output argument types. That would make it impossible to call
any one of the procedures by writing just NULL (or "?", or any other
data-type-free notation) for the output argument(s). The change also
seems likely to cause grave confusion for client applications that
examine pg_proc and expect the traditional definition of proargtypes.
Hence, revert the definition of proargtypes to what it was, and
undo a number of complications that had been added to support that.
To support the SQL-spec behavior of DROP PROCEDURE, when there are
no argmode markers in the command's parameter list, we perform the
lookup both ways (that is, matching against both proargtypes and
proallargtypes), succeeding if we get just one unique match.
In principle this could result in ambiguous-function failures
that would not happen when using only one of the two rules.
However, overloading of procedure names is thought to be a pretty
rare usage, so this shouldn't cause many problems in practice.
Postgres-specific code such as pg_dump can defend against any
possibility of such failures by being careful to specify argmodes
for all procedure arguments.
This also fixes a few other bugs in the area of CALL statements
with named parameters, and improves the documentation a little.
catversion bump forced because the representation of procedures
with OUT arguments changes.
Discussion: https://postgr.es/m/3742981.1621533210@sss.pgh.pa.us
The use of this function is limited to superusers and the code includes
a hardcoded check for that. However, the code would look for the PGPROC
entry to signal for the memory dump before checking if the user is a
superuser or not, which does not make sense if we know that an error
will be returned. Note that the code would let one know if a process
was a PostgreSQL process or not even for non-authorized users, which is
not the case now, but this avoids taking ProcArrayLock that will most
likely finish by being unnecessary.
Thanks to Julien Rouhaud and Tom Lane for the discussion.
Discussion: https://postgr.es/m/YLxw1uVGIAP5uMPl@paquier.xyz
This case should be disallowed, just as FOR UPDATE with a plain
GROUP BY is disallowed; FOR UPDATE only makes sense when each row
of the query result can be identified with a single table row.
However, we missed teaching CheckSelectLocking() to check
groupingSets as well as groupClause, so that it would allow
degenerate grouping sets. That resulted in a bad plan and
a null-pointer dereference in the executor.
Looking around for other instances of the same bug, the only one
I found was in examine_simple_variable(). That'd just lead to
silly estimates, but it should be fixed too.
Per private report from Yaoguang Chen.
Back-patch to all supported branches.
Braces were referred in some error messages as only brackets (not curly
brackets or curly braces), which can be confusing as other types of
brackets could be used.
While on it, add one test to check after the case of junk characters
detected after a right brace.
Author: Kyotaro Horiguchi
Discussion: https://postgr.es/m/20210514.153153.1814935914483287479.horikyota.ntt@gmail.com
Parallel query processes that called BlessTupleDesc() for identical
tuple descriptors at the same moment could crash. There was code to
handle that rare case, but it dereferenced a bogus DSA pointer. Repair.
Back-patch to 11, where commit cc5f8136 added support for sharing tuple
descriptors in parallel queries.
Reported-by: Eric Thinnes <e.thinnes@gmx.de>
Discussion: https://postgr.es/m/99aaa2eb-e194-bf07-c29a-1a76b4f2bcf9%40gmx.de
Redefine '\0' (InvalidCompressionMethod) as meaning "if we need to
compress, use the current setting of default_toast_compression".
This allows '\0' to be a suitable default choice regardless of
datatype, greatly simplifying code paths that initialize tupledescs
and the like. It seems like a more user-friendly approach as well,
because now the default compression choice doesn't migrate into table
definitions, meaning that changing default_toast_compression is
usually sufficient to flip an installation's behavior; one needn't
tediously issue per-column ALTER SET COMPRESSION commands.
Along the way, fix a few minor bugs and documentation issues
with the per-column-compression feature. Adopt more robust
APIs for SetIndexStorageProperties and GetAttributeCompression.
Bump catversion because typical contents of attcompression will now
be different. We could get away without doing that, but it seems
better to ensure v14 installations all agree on this. (We already
forced initdb for beta2, anyway.)
Discussion: https://postgr.es/m/626613.1621787110@sss.pgh.pa.us
The following parameters have been imprecise, or incorrect, about their
description (PGC_POSTMASTER or PGC_SIGHUP):
- autovacuum_work_mem (docs, as of 9.6~)
- huge_page_size (docs, as of 14~)
- max_logical_replication_workers (docs, as of 10~)
- max_sync_workers_per_subscription (docs, as of 10~)
- min_dynamic_shared_memory (docs, as of 14~)
- recovery_init_sync_method (postgresql.conf.sample, as of 14~)
- remove_temp_files_after_crash (docs, as of 14~)
- restart_after_crash (docs, as of 9.6~)
- ssl_min_protocol_version (docs, as of 12~)
- ssl_max_protocol_version (docs, as of 12~)
This commit adjusts the description of all these parameters to be more
consistent with the practice used for the others.
Revewed-by: Justin Pryzby
Discussion: https://postgr.es/m/YK2ltuLpe+FbRXzA@paquier.xyz
Backpatch-through: 9.6
COMMIT/ROLLBACK necessarily destroys all snapshots within the session.
The original implementation of intra-procedure transactions just
cavalierly did that, ignoring the fact that this left us executing in
a rather different environment than normal. In particular, it turns
out that handling of toasted datums depends rather critically on there
being an outer ActiveSnapshot: otherwise, when SPI or the core
executor pop whatever snapshot they used and return, it's unsafe to
dereference any toasted datums that may appear in the query result.
It's possible to demonstrate "no known snapshots" and "missing chunk
number N for toast value" errors as a result of this oversight.
Historically this outer snapshot has been held by the Portal code,
and that seems like a good plan to preserve. So add infrastructure
to pquery.c to allow re-establishing the Portal-owned snapshot if it's
not there anymore, and add enough bookkeeping support that we can tell
whether it is or not.
We can't, however, just re-establish the Portal snapshot as part of
COMMIT/ROLLBACK. As in normal transaction start, acquiring the first
snapshot should wait until after SET and LOCK commands. Hence, teach
spi.c about doing this at the right time. (Note that this patch
doesn't fix the problem for any PLs that try to run intra-procedure
transactions without using SPI to execute SQL commands.)
This makes SPI's no_snapshots parameter rather a misnomer, so in HEAD,
rename that to allow_nonatomic.
replication/logical/worker.c also needs some fixes, because it wasn't
careful to hold a snapshot open around AFTER trigger execution.
That code doesn't use a Portal, which I suspect someday we're gonna
have to fix. But for now, just rearrange the order of operations.
This includes back-patching the recent addition of finish_estate()
to centralize the cleanup logic there.
This also back-patches commit 2ecfeda3e into v13, to improve the
test coverage for worker.c (it was that test that exposed that
worker.c's snapshot management is wrong).
Per bug #15990 from Andreas Wicht. Back-patch to v11 where
intra-procedure COMMIT was added.
Discussion: https://postgr.es/m/15990-eee2ac466b11293d@postgresql.org
Allowing only on/off meant that all either all existing configuration
guides would become obsolete if we disabled it by default, or that we
would have to accept a performance loss in the default config if we
enabled it by default. By allowing 'auto' as a middle ground, the
performance cost is only paid by those who enable pg_stat_statements and
similar modules.
I only edited the release notes to comment-out a paragraph that is now
factually wrong; further edits are probably needed to describe the
related change in more detail.
Author: Julien Rouhaud <rjuju123@gmail.com>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/20210513002623.eugftm4nk2lvvks3@nol
Also "make reformat-dat-files".
The only change worthy of note is that pgindent messed up the formatting
of launcher.c's struct LogicalRepWorkerId, which led me to notice that
that struct wasn't used at all anymore, so I just took it out.
Use a static prolog file instead of generating the prolog from the
existing perl script. Also, support generation of the file in a vpath
build.
Discussion: https://postgr.es/m/700620.1620662868@sss.pgh.pa.us
While we were (mostly) careful about ensuring that the dimensions of
arrays aren't large enough to cause integer overflow, the lower bound
values were generally not checked. This allows situations where
lower_bound + dimension overflows an integer. It seems that that's
harmless so far as array reading is concerned, except that array
elements with subscripts notionally exceeding INT_MAX are inaccessible.
However, it confuses various array-assignment logic, resulting in a
potential for memory stomps.
Fix by adding checks that array lower bounds aren't large enough to
cause lower_bound + dimension to overflow. (Note: this results in
disallowing cases where the last subscript position would be exactly
INT_MAX. In principle we could probably allow that, but there's a lot
of code that computes lower_bound + dimension and would need adjustment.
It seems doubtful that it's worth the trouble/risk to allow it.)
Somewhat independently of that, array_set_element() was careless
about possible overflow when checking the subscript of a fixed-length
array, creating a different route to memory stomps. Fix that too.
Security: CVE-2021-32027
When building without --enable-dtrace, emit dummy
do {} while (0)
statements for the stubbed-out TRACE_POSTGRESQL_foo() macros
instead of empty macros that totally elide the original probe
statement.
This fixes the
warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
introduced by b94409a02f.
Author: Craig Ringer <craig.ringer@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/20210504221531.cfvpmmdfsou6eitb%40alap3.anarazel.de
This set of commits has some bugs with known fixes, but at this late
stage in the release cycle it seems best to revert and resubmit next
time, along with some new automated test coverage for this whole area.
Commits reverted:
dc88460c: Doc: Review for "Optionally prefetch referenced data in recovery."
1d257577: Optionally prefetch referenced data in recovery.
f003d9f8: Add circular WAL decoding buffer.
323cbe7c: Remove read_page callback from XLogReader.
Remove the new GUC group WAL_RECOVERY recently added by a55a9847, as the
corresponding section of config.sgml is now reverted.
Discussion: https://postgr.es/m/CAOuzzgrn7iKnFRsB4MHp3UisEQAGgZMbk_ViTN4HV4-Ksq8zCg%40mail.gmail.com
It seems that various people have moved GUCs around in the config.sgml
listing without bothering to make the code agree. Ensure that the
config_group codes assigned to GUCs match where they are listed in
config.sgml. Likewise ensure that postgresql.conf.sample lists GUCs
in the same sub-section and same ordering as they appear in config.sgml.
(I've got some doubts about some of these choices, but for the purposes
of this patch, we'll treat config.sgml as gospel.)
Notably, this requires adding a WAL_RECOVERY config_group value,
because 1d257577e didn't. As long as we're renumbering that enum
anyway, let's take out the values corresponding to major groups
that are divided into sub-groups. No GUC should be assigned to the
major group itself, so those values just create a temptation to
do the wrong thing, while adding work for translators.
In passing, adjust the short_desc strings for PRESET_OPTIONS GUCs
to uniformly use the phrasing "Shows XYZ.", removing the impression
some of these strings left that you can set the value.
While some of these errors are old, no back-patch, as changing the
contents of the pg_settings view in stable branches seems more likely
to be seen as a compatibility break than anything helpful.
Bharath Rupireddy, Justin Pryzby, Tom Lane
Discussion: https://postgr.es/m/16997-ff16127f6e0d1390@postgresql.org
Discussion: https://postgr.es/m/20210413123139.GE6091@telsasoft.com
The usual behavior for functions in ruleutils.c is to return NULL when
the object does not exist. pg_get_statisticsobjdef_expressions raised an
error instead, so correct that.
Reported-by: Justin Pryzby
Discussion: https://postgr.es/m/20210505210947.GA27406%40telsasoft.com
Design problems were discovered in the handling of composite types and
record types that would cause some relevant versions not to be recorded.
Misgivings were also expressed about the use of the pg_depend catalog
for this purpose. We're out of time for this release so we'll revert
and try again.
Commits reverted:
1bf946bd: Doc: Document known problem with Windows collation versions.
cf002008: Remove no-longer-relevant test case.
ef387bed: Fix bogus collation-version-recording logic.
0fb0a050: Hide internal error for pg_collation_actual_version(<bad OID>).
ff942057: Suppress "warning: variable 'collcollate' set but not used".
d50e3b1f: Fix assertion in collation version lookup.
f24b1569: Rethink extraction of collation dependencies.
257836a7: Track collation versions for indexes.
cd6f479e: Add pg_depend.refobjversion.
7d1297df: Remove pg_collation.collversion.
Discussion: https://postgr.es/m/CA%2BhUKGLhj5t1fcjqAu8iD9B3ixJtsTNqyCCD4V0aTO9kAKAjjA%40mail.gmail.com
Properly fix:
- the "ONLY" in FROM [ONLY] isn't hashed
- the agglevelsup field in GROUPING isn't hashed
- WITH TIES not being hashed (new in PG 13)
- "DISTINCT" in "GROUP BY [DISTINCT]" isn't hashed (new in PG 14)
Reported-by: Julien Rouhaud
Discussion: https://postgr.es/m/20210425081119.ulyzxqz23ueh3wuj@nol
websearch_to_tsquery() splits text in quotes into tokens and connects them with
phrase operator on its own. However, that leads to surprising results when the
token contains no words.
For instance, websearch_to_tsquery('"aaa: bbb"') is 'aaa <2> bbb', because
it is equivalent of to_tsquery(E'aaa <-> \':\' <-> bbb'). But
websearch_to_tsquery('"aaa: bbb"') has to be 'aaa <-> bbb' in order to match
to_tsvector('aaa: bbb').
Since 0c4f355c6a, we anyway connect lexemes of complex tokens with phrase
operators. Thus, let's just websearch_to_tsquery() parse text in quotes as
a single token. Therefore, websearch_to_tsquery() should process the quoted
text in the same way phraseto_tsquery() does. This solution is what we exactly
need and also simplifies the code.
This commit is an incompatible change, so we don't backpatch it.
Reported-by: Valentin Gatien-Baron
Discussion: https://postgr.es/m/CA%2B0DEqiZs7gdOd4ikmg%3D0UWG%2BSwWOLxPsk_JW-sx9WNOyrb0KQ%40mail.gmail.com
Author: Alexander Korotkov
Reviewed-by: Tom Lane, Zhihong Yu
Makes partition descriptor acquisition faster during the transient
period in which a partition is in the process of being detached.
This also adds the restriction that only one partition can be in
pending-detach state for a partitioned table.
While at it, return find_inheritance_children() API to what it was
before 71f4c8c6f7, and create a separate
find_inheritance_children_extended() that returns detailed info about
detached partitions.
(This incidentally fixes a bug in 8aba932251 whereby a memory context
holding a transient partdesc is reparented to a NULL PortalContext,
leading to permanent leak of that memory. The fix is to no longer rely
on reparenting contexts to PortalContext. Reported by Amit Langote.)
Per gripe from Amit Langote
Discussion: https://postgr.es/m/CA+HiwqFgpP1LxJZOBYGt9rpvTjXXkg5qG2+Xch2Z1Q7KrqZR1A@mail.gmail.com
Previously, we used to use the array of size max_replication_slots to
store stats for replication slots. But that had two problems in the cases
where a message for dropping a slot gets lost: 1) the stats for the new
slot are not recorded if the array is full and 2) writing beyond the end
of the array if the user reduces the max_replication_slots.
This commit uses HTAB for replication slot statistics, resolving both
problems. Now, pgstat_vacuum_stat() search for all the dead replication
slots in stats hashtable and tell the collector to remove them. To avoid
showing the stats for the already-dropped slots, pg_stat_replication_slots
view searches slot stats by the slot name taken from pg_replication_slots.
Also, we send a message for creating a slot at slot creation, initializing
the stats. This reduces the possibility that the stats are accumulated
into the old slot stats when a message for dropping a slot gets lost.
Reported-by: Andres Freund
Author: Sawada Masahiko, test case by Vignesh C
Reviewed-by: Amit Kapila, Vignesh C, Dilip Kumar
Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
The Truncate operation acquires an exclusive lock on the target relation
and indexes. It then waits for logical replication of the operation to
finish at commit. Now because we are acquiring the shared lock on the
target index to get index attributes in pgoutput while sending the
changes for the Truncate operation, it leads to a deadlock.
Actually, we don't need to acquire a lock on the target index as we build
the cache entry using a historic snapshot and all the later changes are
absorbed while decoding WAL. So, we wrote a special purpose function for
logical replication to get a bitmap of replica identity attribute numbers
where we get that information without locking the target index.
We decided not to backpatch this as there doesn't seem to be any field
complaint about this issue since it was introduced in commit 5dfd1e5a in
v11.
Reported-by: Haiying Tang
Author: Takamichi Osumi, test case by Li Japin
Reviewed-by: Amit Kapila, Ajin Cherian
Discussion: https://postgr.es/m/OS0PR01MB6113C2499C7DC70EE55ADB82FB759@OS0PR01MB6113.jpnprd01.prod.outlook.com
These functions shouldn't receive null arguments: multirange_constructor0()
doesn't have any arguments while multirange_constructor2() has a single array
argument, which is never null.
But mark them strict anyway for the sake of uniformity.
Also, make checks for null arguments use elog() instead of ereport() as these
errors should normally be never thrown. And adjust corresponding comments.
Catversion is bumped.
Reported-by: Peter Eisentraut
Discussion: https://postgr.es/m/0f783a96-8d67-9e71-996b-f34a7352eeef%40enterprisedb.com
log_statement is issued before query_id can be computed, so properly
clear the value, and document the interaction.
Reported-by: Fujii Masao, Michael Paquier
Discussion: https://postgr.es/m/YHPkU8hFi4no4NSw@paquier.xyz
Author: Julien Rouhaud
Previously, it was pg_stat_activity.queryid to match the
pg_stat_statements queryid column. This is an adjustment to patch
4f0b0966c8. This also adjusts some of the internal function calls to
match. Catversion bumped.
Reported-by: Álvaro Herrera, Julien Rouhaud
Discussion: https://postgr.es/m/20210408032704.GA7498@alvherre.pgsql
This adds the statistics about total transactions count and total
transaction data logically sent to the decoding output plugin from
ReorderBuffer. Users can query the pg_stat_replication_slots view to check
these stats.
Suggested-by: Andres Freund
Author: Vignesh C and Amit Kapila
Reviewed-by: Sawada Masahiko, Amit Kapila
Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
This GUC has always been classified as a planner option since its
introduction in 7c944bd, and was listed in postgresql.conf.sample. As
this parameter exists for testing purposes, move it to the section
dedicated to developer parameters and hence remove it from
postgresql.conf.sample. This will avoid any temptation to play with it
on production servers for users that should never really have to touch
this parameter.
The general description used for developer options is reworded a bit, to
take into account the inclusion of force_parallel_mode, per a suggestion
from Tom Lane.
Per discussion between Tom Lane, Bruce Momjian, Justin Pryzby, Bharath
Rupireddy and me.
Author: Justin Pryzby, Tom Lane
Discussion: https://postgr.es/m/20210403152402.GA8049@momjian.us
This will make it consistent with the other usage of slotname in the code.
In the passing, change pgstat_report_replslot signature to use a structure
rather than multiple parameters.
Reported-by: Andres Freund
Author: Vignesh C
Reviewed-by: Sawada Masahiko, Amit Kapila
Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
Most GUC check hooks that inspect database state have special checks
that prevent them from throwing hard errors for state-dependent issues
when source == PGC_S_TEST. This allows, for example,
"ALTER DATABASE d SET default_text_search_config = foo" when the "foo"
configuration hasn't been created yet. Without this, we have problems
during dump/reload or pg_upgrade, because pg_dump has no idea about
possible dependencies of GUC values and can't ensure a safe restore
ordering.
However, check_role() and check_session_authorization() hadn't gotten
the memo about that, and would throw hard errors anyway. It's not
entirely clear what is the use-case for "ALTER ROLE x SET role = y",
but we've now heard two independent complaints about that bollixing
an upgrade, so apparently some people are doing it.
Hence, fix these two functions to act more like other check hooks
with similar needs. (But I did not change their insistence on
being inside a transaction, as it's still not apparent that setting
either GUC from the configuration file would be wise.)
Also fix check_temp_buffers, which had a different form of the disease
of making state-dependent checks without any exception for PGC_S_TEST.
A cursory survey of other GUC check hooks did not find any more issues
of this ilk. (There are a lot of interdependencies among
PGC_POSTMASTER and PGC_SIGHUP GUCs, which may be a bad idea, but
they're not relevant to the immediate concern because they can't be
set via ALTER ROLE/DATABASE.)
Per reports from Charlie Hornsby and Nathan Bossart. Back-patch
to all supported branches.
Discussion: https://postgr.es/m/HE1P189MB0523B31598B0C772C908088DB7709@HE1P189MB0523.EURP189.PROD.OUTLOOK.COM
Discussion: https://postgr.es/m/20160711223641.1426.86096@wrigleys.postgresql.org
With the Oracle Developer Studio 12.6 compiler, #line directives alter
the current source file location for purposes of #include "..."
directives. Hence, a VPATH build failed with 'cannot find include file:
"specscanner.c"'. With two exceptions, parser-containing directories
already add "-I. -I$(srcdir)"; eliminate the exceptions. Back-patch to
9.6 (all supported versions).
This GUC has already been classified as LOGGING_WHAT, but its location
in postgresql.conf.sample and the documentation did not reflect that, so
fix those inconsistencies.
Author: Justin Pryzby
Discussion: https://postgr.es/m/20210404012546.GK6592@telsasoft.com
Using Roman numbers (via "RM" or "rm") for a conversion to calculate a
number of months has never considered the case of negative numbers,
where a conversion could easily cause out-of-bound memory accesses. The
conversions in themselves were not completely consistent either, as
specifying 12 would result in NULL, but it should mean XII.
This commit reworks the conversion calculation to have a more
consistent behavior:
- If the number of months and years is 0, return NULL.
- If the number of months is positive, return the exact month number.
- If the number of months is negative, do a backward calculation, with
-1 meaning December, -2 November, etc.
Reported-by: Theodor Arsenij Larionov-Trichkin
Author: Julien Rouhaud
Discussion: https://postgr.es/m/16953-f255a18f8c51f1d5@postgresql.org
backpatch-through: 9.6
Coverity complained about possible overflow in expressions like
intresult = tm->tm_sec * 1000000 + fsec;
on the grounds that the multiplication would happen in 32-bit
arithmetic before widening to the int64 result. I think these
are all false positives because of the limited possible range of
tm_sec; but nonetheless it seems silly to spell it like that when
nearby lines have the identical computation written with a 64-bit
constant.
... or more accurately, with an LL constant, which is not project
style. Make all of these use INT64CONST(), as we do elsewhere.
This is all new code from a2da77cdb, so no need for back-patch.
Commit c9c41c7a33 used two different
naming patterns. Standardize on the majority pattern, which was the
only pattern in the last reviewed version of that commit.
Comment fixes are applied on HEAD, and documentation improvements are
applied on back-branches where needed.
Author: Justin Pryzby
Discussion: https://postgr.es/m/20210408164008.GJ6592@telsasoft.com
Backpatch-through: 9.6
Ignore parallel workers in pg_stat_statements
Oversight in 4f0b0966c8 which exposed queryid in parallel workers.
Counters are aggregated by the main backend process so parallel workers
would report duplicated activity, and could also report activity for the
wrong entry as they are only aware of the top level queryid.
Fix thinko in pg_stat_get_activity when retrieving the queryid.
Remove unnecessary call to pgstat_report_queryid().
Reported-by: Amit Kapila, Andres Freund, Thomas Munro
Discussion: https://postgr.es/m/20210408051735.lfbdzun5zdlax5gd@alap3.anarazel.dep634GTSOqnDW86Owrn6qDAVosC5dJjXjp7BMfc5Gz1Q@mail.gmail.com
Author: Julien Rouhaud
Introduce a new GUC recovery_prefetch, disabled by default. When
enabled, look ahead in the WAL and try to initiate asynchronous reading
of referenced data blocks that are not yet cached in our buffer pool.
For now, this is done with posix_fadvise(), which has several caveats.
Better mechanisms will follow in later work on the I/O subsystem.
The GUC maintenance_io_concurrency is used to limit the number of
concurrent I/Os we allow ourselves to initiate, based on pessimistic
heuristics used to infer that I/Os have begun and completed.
The GUC wal_decode_buffer_size is used to limit the maximum distance we
are prepared to read ahead in the WAL to find uncached blocks.
Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com> (parts)
Reviewed-by: Andres Freund <andres@anarazel.de> (parts)
Reviewed-by: Tomas Vondra <tomas.vondra@2ndquadrant.com> (parts)
Tested-by: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Tested-by: Jakub Wartak <Jakub.Wartak@tomtom.com>
Tested-by: Dmitry Dolgov <9erthalion6@gmail.com>
Tested-by: Sait Talha Nisanci <Sait.Nisanci@microsoft.com>
Discussion: https://postgr.es/m/CA%2BhUKGJ4VJN8ttxScUFM8dOKX0BrBiboo5uz1cq%3DAovOddfHpA%40mail.gmail.com
This adds a function, pg_wait_for_backend_termination(), and a new
timeout argument to pg_terminate_backend(), which will wait for the
backend to actually terminate (with or without signaling it to do so
depending on which function is called). The default behaviour of
pg_terminate_backend() remains being timeout=0 which does not waiting.
For pg_wait_for_backend_termination() the default wait is 5 seconds.
Author: Bharath Rupireddy
Reviewed-By: Fujii Masao, David Johnston, Muhammad Usama,
Hou Zhijie, Magnus Hagander
Discussion: https://postgr.es/m/CALj2ACUBpunmyhYZw-kXCYs5NM+h6oG_7Df_Tn4mLmmUQifkqA@mail.gmail.com
This adds support for writing CREATE FUNCTION and CREATE PROCEDURE
statements for language SQL with a function body that conforms to the
SQL standard and is portable to other implementations.
Instead of the PostgreSQL-specific AS $$ string literal $$ syntax,
this allows writing out the SQL statements making up the body
unquoted, either as a single statement:
CREATE FUNCTION add(a integer, b integer) RETURNS integer
LANGUAGE SQL
RETURN a + b;
or as a block
CREATE PROCEDURE insert_data(a integer, b integer)
LANGUAGE SQL
BEGIN ATOMIC
INSERT INTO tbl VALUES (a);
INSERT INTO tbl VALUES (b);
END;
The function body is parsed at function definition time and stored as
expression nodes in a new pg_proc column prosqlbody. So at run time,
no further parsing is required.
However, this form does not support polymorphic arguments, because
there is no more parse analysis done at call time.
Dependencies between the function and the objects it uses are fully
tracked.
A new RETURN statement is introduced. This can only be used inside
function bodies. Internally, it is treated much like a SELECT
statement.
psql needs some new intelligence to keep track of function body
boundaries so that it doesn't send off statements when it sees
semicolons that are inside a function body.
Tested-by: Jaime Casanova <jcasanov@systemguards.com.ec>
Reviewed-by: Julien Rouhaud <rjuju123@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/1c11f1eb-f00c-43b7-799d-2d44132c02d7@2ndquadrant.com
Add a failsafe mechanism that is triggered by VACUUM when it notices
that the table's relfrozenxid and/or relminmxid are dangerously far in
the past. VACUUM checks the age of the table dynamically, at regular
intervals.
When the failsafe triggers, VACUUM takes extraordinary measures to
finish as quickly as possible so that relfrozenxid and/or relminmxid can
be advanced. VACUUM will stop applying any cost-based delay that may be
in effect. VACUUM will also bypass any further index vacuuming and heap
vacuuming -- it only completes whatever remaining pruning and freezing
is required. Bypassing index/heap vacuuming is enabled by commit
8523492d, which made it possible to dynamically trigger the mechanism
already used within VACUUM when it is run with INDEX_CLEANUP off.
It is expected that the failsafe will almost always trigger within an
autovacuum to prevent wraparound, long after the autovacuum began.
However, the failsafe mechanism can trigger in any VACUUM operation.
Even in a non-aggressive VACUUM, where we're likely to not advance
relfrozenxid, it still seems like a good idea to finish off remaining
pruning and freezing. An aggressive/anti-wraparound VACUUM will be
launched immediately afterwards. Note that the anti-wraparound VACUUM
that follows will itself trigger the failsafe, usually before it even
begins its first (and only) pass over the heap.
The failsafe is controlled by two new GUCs: vacuum_failsafe_age, and
vacuum_multixact_failsafe_age. There are no equivalent reloptions,
since that isn't expected to be useful. The GUCs have rather high
defaults (both default to 1.6 billion), and are expected to generally
only be used to make the failsafe trigger sooner/more frequently.
Author: Masahiko Sawada <sawada.mshk@gmail.com>
Author: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAD21AoD0SkE11fMw4jD4RENAwBMcw1wasVnwpJVw3tVqPOQgAw@mail.gmail.com
Discussion: https://postgr.es/m/CAH2-WzmgH3ySGYeC-m-eOBsa2=sDwa292-CFghV4rESYo39FsQ@mail.gmail.com
Use the in-core query id computation for pg_stat_activity,
log_line_prefix, and EXPLAIN VERBOSE.
Similar to other fields in pg_stat_activity, only the queryid from the
top level statements are exposed, and if the backends status isn't
active then the queryid from the last executed statements is displayed.
Add a %Q placeholder to include the queryid in log_line_prefix, which
will also only expose top level statements.
For EXPLAIN VERBOSE, if a query identifier has been computed, either by
enabling compute_query_id or using a third-party module, display it.
Bump catalog version.
Discussion: https://postgr.es/m/20210407125726.tkvjdbw76hxnpwfi@nol
Author: Julien Rouhaud
Reviewed-by: Alvaro Herrera, Nitin Jadhav, Zhihong Yu
Add compute_query_id GUC to control whether a query identifier should be
computed by the core (off by default). It's thefore now possible to
disable core queryid computation and use pg_stat_statements with a
different algorithm to compute the query identifier by using a
third-party module.
To ensure that a single source of query identifier can be used and is
well defined, modules that calculate a query identifier should throw an
error if compute_query_id specified to compute a query id and if a query
idenfitier was already calculated.
Discussion: https://postgr.es/m/20210407125726.tkvjdbw76hxnpwfi@nol
Author: Julien Rouhaud
Reviewed-by: Alvaro Herrera, Nitin Jadhav, Zhihong Yu
Formerly we were pretty lax about what a custom GUC's name could
be; so long as it had at least one dot in it, we'd take it.
However, corner cases such as dashes or equal signs in the name
would cause various bits of functionality to misbehave. Rather
than trying to make the world perfectly safe for that, let's
just require that custom names look like "identifier.identifier",
where "identifier" means something that scan.l would accept
without double quotes.
Along the way, this patch refactors things slightly in guc.c
so that find_option() is responsible for reporting GUC-not-found
cases, allowing removal of duplicative code from its callers.
Per report from Hubert Depesz Lubaczewski. No back-patch,
since the consequences of the problem don't seem to warrant
changing behavior in stable branches.
Discussion: https://postgr.es/m/951335.1612910077@sss.pgh.pa.us
Andrew Gierth reported that it's possible to crash the backend if no
pg_attrdef record is found to match an attribute that has atthasdef set.
AttrDefaultFetch warns about this situation, but then leaves behind
a relation tupdesc that has null "adbin" pointer(s), which most places
don't guard against.
We considered promoting the warning to an error, but throwing errors
during relcache load is pretty drastic: it effectively locks one out
of using the relation at all. What seems better is to leave the
load-time behavior as a warning, but then throw an error in any code
path that wants to use a default and can't find it. This confines
the error to a subset of INSERT/UPDATE operations on the table, and
in particular will at least allow a pg_dump to succeed.
Also, we should fix AttrDefaultFetch to not leave any null pointers
in the tupdesc, because that just creates an untested bug hazard.
While at it, apply the same philosophy of "warn at load, throw error
only upon use of the known-missing info" to CHECK constraints.
CheckConstraintFetch is very nearly the same logic as AttrDefaultFetch,
but for reasons lost in the mists of time, it was throwing ERROR for
the same cases that AttrDefaultFetch treats as WARNING. Make the two
functions more nearly alike.
In passing, get rid of potentially-O(N^2) loops in equalTupleDesc
by making AttrDefaultFetch sort the entries after fetching them,
so that equalTupleDesc can assume that entries in two equal tupdescs
must be in matching order. (CheckConstraintFetch already was sorting
CHECK constraints, but equalTupleDesc hadn't been told about it.)
There's some argument for back-patching this, but with such a small
number of field reports, I'm content to fix it in HEAD.
Discussion: https://postgr.es/m/87pmzaq4gx.fsf@news-spur.riddles.org.uk
The previous implementation of EXTRACT mapped internally to
date_part(), which returned type double precision (since it was
implemented long before the numeric type existed). This can lead to
imprecise output in some cases, so returning numeric would be
preferrable. Changing the return type of an existing function is a
bit risky, so instead we do the following: We implement a new set of
functions, which are now called "extract", in parallel to the existing
date_part functions. They work the same way internally but use
numeric instead of float8. The EXTRACT construct is now mapped by the
parser to these new extract functions. That way, dumps of views
etc. from old versions (which would use date_part) continue to work
unchanged, but new uses will map to the new extract functions.
Additionally, the reverse compilation of EXTRACT now reproduces the
original syntax, using the new mechanism introduced in
40c24bfef9.
The following minor changes of behavior result from the new
implementation:
- The column name from an isolated EXTRACT call is now "extract"
instead of "date_part".
- Extract from date now rejects inappropriate field names such as
HOUR. It was previously mapped internally to extract from
timestamp, so it would silently accept everything appropriate for
timestamp.
- Return values when extracting fields with possibly fractional
values, such as second and epoch, now have the full scale that the
value has internally (so, for example, '1.000000' instead of just
'1').
Reported-by: Petr Fedorov <petr.fedorov@phystech.edu>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/42b73d2d-da12-ba9f-570a-420e0cce19d9@phystech.edu
Commit 3e98c0bafb added pg_backend_memory_contexts view to display
the memory contexts of the backend process. However its target process
is limited to the backend that is accessing to the view. So this is
not so convenient when investigating the local memory bloat of other
backend process. To improve this situation, this commit adds
pg_log_backend_memory_contexts() function that requests to log
the memory contexts of the specified backend process.
This information can be also collected by calling
MemoryContextStats(TopMemoryContext) via a debugger. But
this technique cannot be used in some environments because no debugger
is available there. So, pg_log_backend_memory_contexts() allows us to
see the memory contexts of specified backend more easily.
Only superusers are allowed to request to log the memory contexts
because allowing any users to issue this request at an unbounded rate
would cause lots of log messages and which can lead to denial of service.
On receipt of the request, at the next CHECK_FOR_INTERRUPTS(),
the target backend logs its memory contexts at LOG_SERVER_ONLY level,
so that these memory contexts will appear in the server log but not
be sent to the client. It logs one message per memory context.
Because if it buffers all memory contexts into StringInfo to log them
as one message, which may require the buffer to be enlarged very much
and lead to OOM error since there can be a large number of memory
contexts in a backend.
When a backend process is consuming huge memory, logging all its
memory contexts might overrun available disk space. To prevent this,
now this patch limits the number of child contexts to log per parent
to 100. As with MemoryContextStats(), it supposes that practical cases
where the log gets long will typically be huge numbers of siblings
under the same parent context; while the additional debugging value
from seeing details about individual siblings beyond 100 will not be large.
There was another proposed patch to add the function to return
the memory contexts of specified backend as the result sets,
instead of logging them, in the discussion. However that patch is
not included in this commit because it had several issues to address.
Thanks to Tatsuhito Kasahara, Andres Freund, Tom Lane, Tomas Vondra,
Michael Paquier, Kyotaro Horiguchi and Zhihong Yu for the discussion.
Bump catalog version.
Author: Atsushi Torikoshi
Reviewed-by: Kyotaro Horiguchi, Zhihong Yu, Fujii Masao
Discussion: https://postgr.es/m/0271f440ac77f2a4180e0e56ebd944d1@oss.nttdata.com
spg_box_quad_leaf_consistent unconditionally returned the leaf
datum as leafValue, even though in its usage for poly_ops that
value is of completely the wrong type.
In versions before 12, that was harmless because the core code did
nothing with leafValue in non-index-only scans ... but since commit
2a6368343, if we were doing a KNN-style scan, spgNewHeapItem would
unconditionally try to copy the value using the wrong datatype
parameters. Said copying is a waste of time and space if we're not
going to return the data, but it accidentally failed to fail until
I fixed the datatype confusion in ac9099fc1.
Hence, change spgNewHeapItem to not copy the datum unless we're
actually going to return it later. This saves cycles and dodges
the question of whether lossy opclasses are returning the right
type. Also change spg_box_quad_leaf_consistent to not return
data that might be of the wrong type, as insurance against
somebody introducing a similar bug into the core code in future.
It seems like a good idea to back-patch these two changes into
v12 and v13, although I'm afraid to change spgNewHeapItem's
mistaken idea of which datatype to use in those branches.
Per buildfarm results from ac9099fc1.
Discussion: https://postgr.es/m/3728741.1617381471@sss.pgh.pa.us
pgstat_report_wait_start() and pgstat_report_wait_end() required two
conditional branches so far. One to check if MyProc is NULL, the other to
check if pgstat_track_activities is set. As wait events are used around
comparatively lightweight operations, and are inlined (reducing branch
predictor effectiveness), that's not great.
The dependency on MyProc has a second disadvantage: Low-level subsystems, like
storage/file/fd.c, report wait events, but architecturally it is preferable
for them to not depend on inter-process subsystems like proc.h (defining
PGPROC). After this change including pgstat.h (nor obviously its
sub-components like backend_status.h, wait_event.h, ...) does not pull in IPC
related headers anymore.
These goals, efficiency and abstraction, are achieved by having
pgstat_report_wait_start/end() not interact with MyProc, but instead a new
my_wait_event_info variable. At backend startup it points to a local variable,
removing the need to check for MyProc being NULL. During process
initialization my_wait_event_info is redirected to MyProc->wait_event_info. At
shutdown this is reversed. Because wait event reporting now does not need to
know about where the wait event is stored, it does not need to know about
PGPROC anymore.
The removal of the branch for checking pgstat_track_activities is simpler:
Don't check anymore. The cost due to the branch are often higher than the
store - and even if not, pgstat_track_activities is rarely disabled.
The main motivator to commit this work now is that removing the (indirect)
pgproc.h include from pgstat.h simplifies a patch to move statistics reporting
to shared memory (which still has a chance to get into 14).
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210402194458.2vu324hkk2djq6ce@alap3.anarazel.de
Backend status (supporting pg_stat_activity) and command
progress (supporting pg_stat_progress*) related code is largely
independent from the rest of pgstat.[ch] (supporting views like
pg_stat_all_tables that accumulate data over time). See also
a333476b92.
This commit doesn't rename the function names to make the distinction
from the rest of pgstat_ clearer - that'd be more invasive and not
clearly beneficial. If we were to decide to do such a rename at some
point, it's better done separately from moving the code as well.
Robert's review was of an earlier version.
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20210316195440.twxmlov24rr2nxrg@alap3.anarazel.de
Similarly to the cryptohash implementations, this refactors the existing
HMAC code into a single set of APIs that can be plugged with any crypto
libraries PostgreSQL is built with (only OpenSSL currently). If there
is no such libraries, a fallback implementation is available. Those new
APIs are designed similarly to the existing cryptohash layer, so there
is no real new design here, with the same logic around buffer bound
checks and memory handling.
HMAC has a dependency on cryptohashes, so all the cryptohash types
supported by cryptohash{_openssl}.c can be used with HMAC. This
refactoring is an advantage mainly for SCRAM, that included its own
implementation of HMAC with SHA256 without relying on the existing
crypto libraries even if PostgreSQL was built with their support.
This code has been tested on Windows and Linux, with and without
OpenSSL, across all the versions supported on HEAD from 1.1.1 down to
1.0.1. I have also checked that the implementations are working fine
using some sample results, a custom extension of my own, and doing
cross-checks across different major versions with SCRAM with the client
and the backend.
Author: Michael Paquier
Reviewed-by: Bruce Momjian
Discussion: https://postgr.es/m/X9m0nkEJEzIPXjeZ@paquier.xyz
The wait event related code is independent from the rest of the
pgstat.[ch] code, of nontrivial size and changes on a regular
basis. Put it into its own set of files.
As there doesn't seem to be a good pre-existing directory for code
like this, add src/backend/utils/activity.
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20210316195440.twxmlov24rr2nxrg@alap3.anarazel.de
Provide a new GUC check_client_connection_interval that can be used to
check whether the client connection has gone away, while running very
long queries. It is disabled by default.
For now this uses a non-standard Linux extension (also adopted by at
least one other OS). POLLRDHUP is not defined by POSIX, and other OSes
don't have a reliable way to know if a connection was closed without
actually trying to read or write.
In future we might consider trying to send a no-op/heartbeat message
instead, but that could require protocol changes.
Author: Sergey Cherkashin <s.cherkashin@postgrespro.ru>
Author: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Tatsuo Ishii <ishii@sraoss.co.jp>
Reviewed-by: Konstantin Knizhnik <k.knizhnik@postgrespro.ru>
Reviewed-by: Zhihong Yu <zyu@yugabyte.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Maksim Milyutin <milyutinma@gmail.com>
Reviewed-by: Tsunakawa, Takayuki/綱川 貴之 <tsunakawa.takay@fujitsu.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (much earlier version)
Discussion: https://postgr.es/m/77def86b27e41f0efcba411460e929ae%40postgrespro.ru
Commit dd136052b established a policy that error message FILE items
should include only the base name of the reporting source file, for
uniformity and succinctness. We now observe that some Windows compilers
use backslashes in __FILE__ strings, so truncate at backslashes as well.
This is expected to fix some platform variation in the results of the
new libpq_pipeline test module.
Discussion: https://postgr.es/m/3650140.1617372290@sss.pgh.pa.us
Here we add a new executor node type named "Result Cache". The planner
can include this node type in the plan to have the executor cache the
results from the inner side of parameterized nested loop joins. This
allows caching of tuples for sets of parameters so that in the event that
the node sees the same parameter values again, it can just return the
cached tuples instead of rescanning the inner side of the join all over
again. Internally, result cache uses a hash table in order to quickly
find tuples that have been previously cached.
For certain data sets, this can significantly improve the performance of
joins. The best cases for using this new node type are for join problems
where a large portion of the tuples from the inner side of the join have
no join partner on the outer side of the join. In such cases, hash join
would have to hash values that are never looked up, thus bloating the hash
table and possibly causing it to multi-batch. Merge joins would have to
skip over all of the unmatched rows. If we use a nested loop join with a
result cache, then we only cache tuples that have at least one join
partner on the outer side of the join. The benefits of using a
parameterized nested loop with a result cache increase when there are
fewer distinct values being looked up and the number of lookups of each
value is large. Also, hash probes to lookup the cache can be much faster
than the hash probe in a hash join as it's common that the result cache's
hash table is much smaller than the hash join's due to result cache only
caching useful tuples rather than all tuples from the inner side of the
join. This variation in hash probe performance is more significant when
the hash join's hash table no longer fits into the CPU's L3 cache, but the
result cache's hash table does. The apparent "random" access of hash
buckets with each hash probe can cause a poor L3 cache hit ratio for large
hash tables. Smaller hash tables generally perform better.
The hash table used for the cache limits itself to not exceeding work_mem
* hash_mem_multiplier in size. We maintain a dlist of keys for this cache
and when we're adding new tuples and realize we've exceeded the memory
budget, we evict cache entries starting with the least recently used ones
until we have enough memory to add the new tuples to the cache.
For parameterized nested loop joins, we now consider using one of these
result cache nodes in between the nested loop node and its inner node. We
determine when this might be useful based on cost, which is primarily
driven off of what the expected cache hit ratio will be. Estimating the
cache hit ratio relies on having good distinct estimates on the nested
loop's parameters.
For now, the planner will only consider using a result cache for
parameterized nested loop joins. This works for both normal joins and
also for LATERAL type joins to subqueries. It is possible to use this new
node for other uses in the future. For example, to cache results from
correlated subqueries. However, that's not done here due to some
difficulties obtaining a distinct estimation on the outer plan to
calculate the estimated cache hit ratio. Currently we plan the inner plan
before planning the outer plan so there is no good way to know if a result
cache would be useful or not since we can't estimate the number of times
the subplan will be called until the outer plan is generated.
The functionality being added here is newly introducing a dependency on
the return value of estimate_num_groups() during the join search.
Previously, during the join search, we only ever needed to perform
selectivity estimations. With this commit, we need to use
estimate_num_groups() in order to estimate what the hit ratio on the
result cache will be. In simple terms, if we expect 10 distinct values
and we expect 1000 outer rows, then we'll estimate the hit ratio to be
99%. Since cache hits are very cheap compared to scanning the underlying
nodes on the inner side of the nested loop join, then this will
significantly reduce the planner's cost for the join. However, it's
fairly easy to see here that things will go bad when estimate_num_groups()
incorrectly returns a value that's significantly lower than the actual
number of distinct values. If this happens then that may cause us to make
use of a nested loop join with a result cache instead of some other join
type, such as a merge or hash join. Our distinct estimations have been
known to be a source of trouble in the past, so the extra reliance on them
here could cause the planner to choose slower plans than it did previous
to having this feature. Distinct estimations are also fairly hard to
estimate accurately when several tables have been joined already or when a
WHERE clause filters out a set of values that are correlated to the
expressions we're estimating the number of distinct value for.
For now, the costing we perform during query planning for result caches
does put quite a bit of faith in the distinct estimations being accurate.
When these are accurate then we should generally see faster execution
times for plans containing a result cache. However, in the real world, we
may find that we need to either change the costings to put less trust in
the distinct estimations being accurate or perhaps even disable this
feature by default. There's always an element of risk when we teach the
query planner to do new tricks that it decides to use that new trick at
the wrong time and causes a regression. Users may opt to get the old
behavior by turning the feature off using the enable_resultcache GUC.
Currently, this is enabled by default. It remains to be seen if we'll
maintain that setting for the release.
Additionally, the name "Result Cache" is the best name I could think of
for this new node at the time I started writing the patch. Nobody seems
to strongly dislike the name. A few people did suggest other names but no
other name seemed to dominate in the brief discussion that there was about
names. Let's allow the beta period to see if the current name pleases
enough people. If there's some consensus on a better name, then we can
change it before the release. Please see the 2nd discussion link below
for the discussion on the "Result Cache" name.
Author: David Rowley
Reviewed-by: Andy Fan, Justin Pryzby, Zhihong Yu, Hou Zhijie
Tested-By: Konstantin Knizhnik
Discussion: https://postgr.es/m/CAApHDvrPcQyQdWERGYWx8J%2B2DLUNgXu%2BfOSbQ1UscxrunyXyrQ%40mail.gmail.com
Discussion: https://postgr.es/m/CAApHDvq=yQXr5kqhRviT2RhNKwToaWr9JAN5t+5_PzhuRJ3wvg@mail.gmail.com
Through various refactorings over time, the extract(timezone_minute
from time with time zone) and extract(timezone_minute from timestamp
with time zone) implementations ended up with two different but
equally nonsensical formulas by using SECS_PER_MINUTE and
MINS_PER_HOUR interchangeably. Since those two are of course both the
same number, the formulas do work, but for readability, fix them to be
semantically correct.
With the 'noError' argument, you can try to convert a buffer without
knowing the character boundaries beforehand. The functions now need to
return the number of input bytes successfully converted.
This is is a backwards-incompatible change, if you have created a custom
encoding conversion with CREATE CONVERSION. This adds a check to
pg_upgrade for that, refusing the upgrade if there are any user-defined
encoding conversions. Custom conversions are very rare, there are no
commonly used extensions that I know of that uses that feature. No other
objects can depend on conversions, so if you do have one, you can fairly
easily drop it before upgrading, and recreate it after the upgrade with
an updated version.
Add regression tests for built-in encoding conversions. This doesn't cover
every conversion, but it covers all the internal functions in conv.c that
are used to implement the conversions.
Reviewed-by: John Naylor
Discussion: https://www.postgresql.org/message-id/e7861509-3960-538a-9025-b75a61188e01%40iki.fi
This removes "Add Result Cache executor node". It seems that something
weird is going on with the tracking of cache hits and misses as
highlighted by many buildfarm animals. It's not yet clear what the
problem is as other parts of the plan indicate that the cache did work
correctly, it's just the hits and misses that were being reported as 0.
This is especially a bad time to have the buildfarm so broken, so
reverting before too many more animals go red.
Discussion: https://postgr.es/m/CAApHDvq_hydhfovm4=izgWs+C5HqEeRScjMbOgbpC-jRAeK3Yw@mail.gmail.com
Here we add a new executor node type named "Result Cache". The planner
can include this node type in the plan to have the executor cache the
results from the inner side of parameterized nested loop joins. This
allows caching of tuples for sets of parameters so that in the event that
the node sees the same parameter values again, it can just return the
cached tuples instead of rescanning the inner side of the join all over
again. Internally, result cache uses a hash table in order to quickly
find tuples that have been previously cached.
For certain data sets, this can significantly improve the performance of
joins. The best cases for using this new node type are for join problems
where a large portion of the tuples from the inner side of the join have
no join partner on the outer side of the join. In such cases, hash join
would have to hash values that are never looked up, thus bloating the hash
table and possibly causing it to multi-batch. Merge joins would have to
skip over all of the unmatched rows. If we use a nested loop join with a
result cache, then we only cache tuples that have at least one join
partner on the outer side of the join. The benefits of using a
parameterized nested loop with a result cache increase when there are
fewer distinct values being looked up and the number of lookups of each
value is large. Also, hash probes to lookup the cache can be much faster
than the hash probe in a hash join as it's common that the result cache's
hash table is much smaller than the hash join's due to result cache only
caching useful tuples rather than all tuples from the inner side of the
join. This variation in hash probe performance is more significant when
the hash join's hash table no longer fits into the CPU's L3 cache, but the
result cache's hash table does. The apparent "random" access of hash
buckets with each hash probe can cause a poor L3 cache hit ratio for large
hash tables. Smaller hash tables generally perform better.
The hash table used for the cache limits itself to not exceeding work_mem
* hash_mem_multiplier in size. We maintain a dlist of keys for this cache
and when we're adding new tuples and realize we've exceeded the memory
budget, we evict cache entries starting with the least recently used ones
until we have enough memory to add the new tuples to the cache.
For parameterized nested loop joins, we now consider using one of these
result cache nodes in between the nested loop node and its inner node. We
determine when this might be useful based on cost, which is primarily
driven off of what the expected cache hit ratio will be. Estimating the
cache hit ratio relies on having good distinct estimates on the nested
loop's parameters.
For now, the planner will only consider using a result cache for
parameterized nested loop joins. This works for both normal joins and
also for LATERAL type joins to subqueries. It is possible to use this new
node for other uses in the future. For example, to cache results from
correlated subqueries. However, that's not done here due to some
difficulties obtaining a distinct estimation on the outer plan to
calculate the estimated cache hit ratio. Currently we plan the inner plan
before planning the outer plan so there is no good way to know if a result
cache would be useful or not since we can't estimate the number of times
the subplan will be called until the outer plan is generated.
The functionality being added here is newly introducing a dependency on
the return value of estimate_num_groups() during the join search.
Previously, during the join search, we only ever needed to perform
selectivity estimations. With this commit, we need to use
estimate_num_groups() in order to estimate what the hit ratio on the
result cache will be. In simple terms, if we expect 10 distinct values
and we expect 1000 outer rows, then we'll estimate the hit ratio to be
99%. Since cache hits are very cheap compared to scanning the underlying
nodes on the inner side of the nested loop join, then this will
significantly reduce the planner's cost for the join. However, it's
fairly easy to see here that things will go bad when estimate_num_groups()
incorrectly returns a value that's significantly lower than the actual
number of distinct values. If this happens then that may cause us to make
use of a nested loop join with a result cache instead of some other join
type, such as a merge or hash join. Our distinct estimations have been
known to be a source of trouble in the past, so the extra reliance on them
here could cause the planner to choose slower plans than it did previous
to having this feature. Distinct estimations are also fairly hard to
estimate accurately when several tables have been joined already or when a
WHERE clause filters out a set of values that are correlated to the
expressions we're estimating the number of distinct value for.
For now, the costing we perform during query planning for result caches
does put quite a bit of faith in the distinct estimations being accurate.
When these are accurate then we should generally see faster execution
times for plans containing a result cache. However, in the real world, we
may find that we need to either change the costings to put less trust in
the distinct estimations being accurate or perhaps even disable this
feature by default. There's always an element of risk when we teach the
query planner to do new tricks that it decides to use that new trick at
the wrong time and causes a regression. Users may opt to get the old
behavior by turning the feature off using the enable_resultcache GUC.
Currently, this is enabled by default. It remains to be seen if we'll
maintain that setting for the release.
Additionally, the name "Result Cache" is the best name I could think of
for this new node at the time I started writing the patch. Nobody seems
to strongly dislike the name. A few people did suggest other names but no
other name seemed to dominate in the brief discussion that there was about
names. Let's allow the beta period to see if the current name pleases
enough people. If there's some consensus on a better name, then we can
change it before the release. Please see the 2nd discussion link below
for the discussion on the "Result Cache" name.
Author: David Rowley
Reviewed-by: Andy Fan, Justin Pryzby, Zhihong Yu
Tested-By: Konstantin Knizhnik
Discussion: https://postgr.es/m/CAApHDvrPcQyQdWERGYWx8J%2B2DLUNgXu%2BfOSbQ1UscxrunyXyrQ%40mail.gmail.com
Discussion: https://postgr.es/m/CAApHDvq=yQXr5kqhRviT2RhNKwToaWr9JAN5t+5_PzhuRJ3wvg@mail.gmail.com
According to the comments, when an invalid or dropped column oid is passed
to has_column_privilege(), the intention has always been to return NULL.
However, when the caller had table level privilege the invalid/missing
column was never discovered, because table permissions were checked first.
Fix that by introducing extended versions of pg_attribute_acl(check|mask)
and pg_class_acl(check|mask) which take a new argument, is_missing. When
is_missing is NULL, the old behavior is preserved. But when is_missing is
passed by the caller, no ERROR is thrown for dropped or missing
columns/relations, and is_missing is flipped to true. This in turn allows
has_column_privilege to check for column privileges first, providing the
desired semantics.
Not backpatched since it is a user visible behavioral change with no previous
complaints, and the fix is a bit on the invasive side.
Author: Joe Conway
Reviewed-By: Tom Lane
Reported by: Ian Barwick
Discussion: https://postgr.es/m/flat/9b5f4311-157b-4164-7fe7-077b4fe8ed84%40joeconway.com
This patch makes two closely related sets of changes:
1. For UPDATE, the subplan of the ModifyTable node now only delivers
the new values of the changed columns (i.e., the expressions computed
in the query's SET clause) plus row identity information such as CTID.
ModifyTable must re-fetch the original tuple to merge in the old
values of any unchanged columns. The core advantage of this is that
the changed columns are uniform across all tables of an inherited or
partitioned target relation, whereas the other columns might not be.
A secondary advantage, when the UPDATE involves joins, is that less
data needs to pass through the plan tree. The disadvantage of course
is an extra fetch of each tuple to be updated. However, that seems to
be very nearly free in context; even worst-case tests don't show it to
add more than a couple percent to the total query cost. At some point
it might be interesting to combine the re-fetch with the tuple access
that ModifyTable must do anyway to mark the old tuple dead; but that
would require a good deal of refactoring and it seems it wouldn't buy
all that much, so this patch doesn't attempt it.
2. For inherited UPDATE/DELETE, instead of generating a separate
subplan for each target relation, we now generate a single subplan
that is just exactly like a SELECT's plan, then stick ModifyTable
on top of that. To let ModifyTable know which target relation a
given incoming row refers to, a tableoid junk column is added to
the row identity information. This gets rid of the horrid hack
that was inheritance_planner(), eliminating O(N^2) planning cost
and memory consumption in cases where there were many unprunable
target relations.
Point 2 of course requires point 1, so that there is a uniform
definition of the non-junk columns to be returned by the subplan.
We can't insist on uniform definition of the row identity junk
columns however, if we want to keep the ability to have both
plain and foreign tables in a partitioning hierarchy. Since
it wouldn't scale very far to have every child table have its
own row identity column, this patch includes provisions to merge
similar row identity columns into one column of the subplan result.
In particular, we can merge the whole-row Vars typically used as
row identity by FDWs into one column by pretending they are type
RECORD. (It's still okay for the actual composite Datums to be
labeled with the table's rowtype OID, though.)
There is more that can be done to file down residual inefficiencies
in this patch, but it seems to be committable now.
FDW authors should note several API changes:
* The argument list for AddForeignUpdateTargets() has changed, and so
has the method it must use for adding junk columns to the query. Call
add_row_identity_var() instead of manipulating the parse tree directly.
You might want to reconsider exactly what you're adding, too.
* PlanDirectModify() must now work a little harder to find the
ForeignScan plan node; if the foreign table is part of a partitioning
hierarchy then the ForeignScan might not be the direct child of
ModifyTable. See postgres_fdw for sample code.
* To check whether a relation is a target relation, it's no
longer sufficient to compare its relid to root->parse->resultRelation.
Instead, check it against all_result_relids or leaf_result_relids,
as appropriate.
Amit Langote and Tom Lane
Discussion: https://postgr.es/m/CA+HiwqHpHdqdDn48yCEhynnniahH78rwcrv1rEX65-fsZGBOLQ@mail.gmail.com
This allows something like
SELECT ... FROM t1 JOIN t2 USING (a, b, c) AS x
where x has the columns a, b, c and unlike a regular alias it does not
hide the range variables of the tables being joined t1 and t2.
Per SQL:2016 feature F404 "Range variable for common column names".
Reviewed-by: Vik Fearing <vik.fearing@2ndquadrant.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/454638cf-d563-ab76-a585-2564428062af@2ndquadrant.com
This implements asynchronous execution, which runs multiple parts of a
non-parallel-aware Append concurrently rather than serially to improve
performance when possible. Currently, the only node type that can be
run concurrently is a ForeignScan that is an immediate child of such an
Append. In the case where such ForeignScans access data on different
remote servers, this would run those ForeignScans concurrently, and
overlap the remote operations to be performed simultaneously, so it'll
improve the performance especially when the operations involve
time-consuming ones such as remote join and remote aggregation.
We may extend this to other node types such as joins or aggregates over
ForeignScans in the future.
This also adds the support for postgres_fdw, which is enabled by the
table-level/server-level option "async_capable". The default is false.
Robert Haas, Kyotaro Horiguchi, Thomas Munro, and myself. This commit
is mostly based on the patch proposed by Robert Haas, but also uses
stuff from the patch proposed by Kyotaro Horiguchi and from the patch
proposed by Thomas Munro. Reviewed by Kyotaro Horiguchi, Konstantin
Knizhnik, Andrey Lepikhov, Movead Li, Thomas Munro, Justin Pryzby, and
others.
Discussion: https://postgr.es/m/CA%2BTgmoaXQEt4tZ03FtQhnzeDEMzBck%2BLrni0UWHVVgOTnA6C1w%40mail.gmail.com
Discussion: https://postgr.es/m/CA%2BhUKGLBRyu0rHrDCMC4%3DRn3252gogyp1SjOgG8SEKKZv%3DFwfQ%40mail.gmail.com
Discussion: https://postgr.es/m/20200228.170650.667613673625155850.horikyota.ntt%40gmail.com
Here we add a new output parameter to estimate_num_groups() to allow it to
inform the caller of additional, possibly useful information about the
estimation.
The new output parameter is a struct that currently contains just a single
field with a set of flags. This was done rather than having the flags as
an output parameter to allow future fields to be added without having to
change the signature of the function at a later date when we want to pass
back further information that might not be suitable to store in the flags
field.
It seems reasonable that one day in the future that the planner would want
to know more about the estimation. For example, how many individual sets
of statistics was the estimation generated from? The planner may want to
take that into account if we ever want to consider risks as well as costs
when generating plans.
For now, there's only 1 flag we set in the flags field. This is to
indicate if the estimation fell back on using the hard-coded constants in
any part of the estimation. Callers may like to change their behavior if
this is set, and this gives them the ability to do so. Callers may pass
the flag pointer as NULL if they have no interest in obtaining any
additional information about the estimate.
We're not adding any actual usages of these flags here. Some follow-up
commits will make use of this feature. Additionally, we're also not
making any changes to add support for clauselist_selectivity() and
clauselist_selectivity_ext(). However, if this is required in the future
then the same struct being added here should be fine to use as a new
output argument for those functions too.
Author: David Rowley
Discussion: https://postgr.es/m/CAApHDvqQqpk=1W-G_ds7A9CsXX3BggWj_7okinzkLVhDubQzjA@mail.gmail.com
Allow defining extended statistics on expressions, not just just on
simple column references. With this commit, expressions are supported
by all existing extended statistics kinds, improving the same types of
estimates. A simple example may look like this:
CREATE TABLE t (a int);
CREATE STATISTICS s ON mod(a,10), mod(a,20) FROM t;
ANALYZE t;
The collected statistics are useful e.g. to estimate queries with those
expressions in WHERE or GROUP BY clauses:
SELECT * FROM t WHERE mod(a,10) = 0 AND mod(a,20) = 0;
SELECT 1 FROM t GROUP BY mod(a,10), mod(a,20);
This introduces new internal statistics kind 'e' (expressions) which is
built automatically when the statistics object definition includes any
expressions. This represents single-expression statistics, as if there
was an expression index (but without the index maintenance overhead).
The statistics is stored in pg_statistics_ext_data as an array of
composite types, which is possible thanks to 79f6a942bd.
CREATE STATISTICS allows building statistics on a single expression, in
which case in which case it's not possible to specify statistics kinds.
A new system view pg_stats_ext_exprs can be used to display expression
statistics, similarly to pg_stats and pg_stats_ext views.
ALTER TABLE ... ALTER COLUMN ... TYPE now treats indexes the same way it
treats indexes, i.e. it drops and recreates the statistics. This means
all statistics are reset, and we no longer try to preserve at least the
functional dependencies. This should not be a major issue in practice,
as the functional dependencies actually rely on per-column statistics,
which were always reset anyway.
Author: Tomas Vondra
Reviewed-by: Justin Pryzby, Dean Rasheed, Zhihong Yu
Discussion: https://postgr.es/m/ad7891d2-e90c-b446-9fe2-7419143847d7%40enterprisedb.com
When estimating the number of groups using extended statistics, the code
was discarding information about system attributes. This led to strange
situation that
SELECT 1 FROM t GROUP BY ctid;
could have produced higher estimate (equal to pg_class.reltuples) than
SELECT 1 FROM t GROUP BY a, b, ctid;
with extended statistics on (a,b). Fixed by retaining information about
the system attribute.
Backpatch all the way to 10, where extended statistics were introduced.
Author: Tomas Vondra
Backpatch-through: 10
Membership consists, implicitly, of the current database owner. Expect
use in template databases. Once pg_database_owner has rights within a
template, each owner of a database instantiated from that template will
exercise those rights.
Reviewed by John Naylor.
Discussion: https://postgr.es/m/20201228043148.GA1053024@rfd.leadboat.com
Allow a partition be detached from its partitioned table without
blocking concurrent queries, by running in two transactions and only
requiring ShareUpdateExclusive in the partitioned table.
Because it runs in two transactions, it cannot be used in a transaction
block. This is the main reason to use dedicated syntax: so that users
can choose to use the original mode if they need it. But also, it
doesn't work when a default partition exists (because an exclusive lock
would still need to be obtained on it, in order to change its partition
constraint.)
In case the second transaction is cancelled or a crash occurs, there's
ALTER TABLE .. DETACH PARTITION .. FINALIZE, which executes the final
steps.
The main trick to make this work is the addition of column
pg_inherits.inhdetachpending, initially false; can only be set true in
the first part of this command. Once that is committed, concurrent
transactions that use a PartitionDirectory will include or ignore
partitions so marked: in optimizer they are ignored if the row is marked
committed for the snapshot; in executor they are always included. As a
result, and because of the way PartitionDirectory caches partition
descriptors, queries that were planned before the detach will see the
rows in the detached partition and queries that are planned after the
detach, won't.
A CHECK constraint is created that duplicates the partition constraint.
This is probably not strictly necessary, and some users will prefer to
remove it afterwards, but if the partition is re-attached to a
partitioned table, the constraint needn't be rechecked.
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Amit Langote <amitlangote09@gmail.com>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/20200803234854.GA24158@alvherre.pgsql
Tomas Vondra
Thomas Munro
Peter Eisentraut
Tom Lane
Michael Paquier
Fujii Masao
Bruce Momjian
Robert Haas
Alexander Korotkov
Daniel Gustafsson
Amit Kapila
David Rowley
Andres Freund
Jeff Davis
Heikki Linnakangas
Noah Misch
Dean Rasheed
John Naylor
Alvaro Herrera
Andrew Dunstan
Magnus Hagander
Peter Geoghegan
Stephen Frost
Joe Conway
Etsuro Fujita