Per-character pg_locale_t APIs. Useful for tsearch parsing and
potentially other places.
Significant overlap with the regc_wc_isalpha() and related functions
in regc_pg_locale.c, but this change leaves those intact for
now.
Discussion: https://postgr.es/m/0151ad01239e2cc7b3139644358cf8f7b9622ff7.camel@j-davis.com
The log output functionality of log_autovacuum_min_duration applies to
both VACUUM and ANALYZE, so it is not possible to separate the VACUUM
and ANALYZE log output thresholds. Logs are likely to be output only for
VACUUM and not for ANALYZE.
Therefore, we decided to separate the threshold for log output of VACUUM
by autovacuum (log_autovacuum_min_duration) and the threshold for log
output of ANALYZE by autovacuum (log_autoanalyze_min_duration).
Author: Shinya Kato <shinya11.kato@gmail.com>
Reviewed-by: Kasahara Tatsuhito <kasaharatt@oss.nttdata.com>
Discussion: https://www.postgresql.org/message-id/flat/CAOzEurQtfV4MxJiWT-XDnimEeZAY+rgzVSLe8YsyEKhZcajzSA@mail.gmail.com
log_error() would probably fail completely if used, and would
certainly print garbage for anything that needed to be interpolated
into the message, because it was failing to use the correct printing
subroutine for a va_list argument.
This bug likely went undetected because the error cases this code
is used for are rarely exercised - they only occur when Windows
security API calls fail catastrophically (out of memory, security
subsystem corruption, etc).
The FRONTEND variant can be fixed just by calling vfprintf()
instead of fprintf(). However, there was no va_list variant
of write_stderr(), so create one by refactoring that function.
Following the usual naming convention for such things, call
it vwrite_stderr().
Author: Bryan Green <dbryan.green@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CAF+pBj8goe4fRmZ0V3Cs6eyWzYLvK+HvFLYEYWG=TzaM+tWPnw@mail.gmail.com
Backpatch-through: 13
In the same spirit as 3bf905692, assume that all compilers we still
support provide the NAN macro, and get rid of workarounds for that.
The C standard allows implementations to omit NAN if the underlying
float arithmetic lacks quiet (non-signaling) NaNs. However, we've
required that feature for years: the workarounds only supported
lack of the macro, not lack of the functionality. I put in a
compile-time #error if there's no macro, just for clarity.
Also fix up the copies of these functions in ecpglib, and leave
a breadcrumb for the next hacker who touches them.
History of the hacks being removed here can be found in commits
1bc2d544b, 4d17a2146, cec8394b5.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/1952095.1759764279@sss.pgh.pa.us
It is possible to call pg_stat_reset_single_function_counters() for a
single function, but the reset time was missing the system view showing
its statistics. Like all the fields of pg_stat_user_functions, the GUC
track_functions needs to be enabled to show the statistics about
function executions.
Bump catalog version.
Bump PGSTAT_FILE_FORMAT_ID, as a result of the new field added to
PgStat_StatFuncEntry.
Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://postgr.es/m/aONjnsaJSx-nEdfU@paquier.xyz
The INFINITY macro is always defined per C99 standard, so this should
mean we can now get rid of the workaround code for when that macro isn't
defined.
Also, delete the (now unneeded) #pragma code which was disabling a
compiler warning in MSVC. There was a comment explaining why the #pragma
was placed outside the function body to work around a MSVC compiler bug,
but the link explaining that was dead, as reported by jian he.
Author: David Rowley <dgrowleyml@gmail.com>
Reported-by: jian he <jian.universality@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CACJufxGARYETnNwtCK7QC0zE_7gq-tfN0mME=gT5rTNtC=VSHQ@mail.gmail.com
It is possible to call pg_stat_reset_single_table_counters() on a
relation (index or table) but the reset time was missing from the system
views showing their statistics.
This commit adds the reset time as an attribute of pg_stat_all_tables,
pg_stat_all_indexes, and other relations related to them.
Bump catalog version.
Bump PGSTAT_FILE_FORMAT_ID, as a result of the new field added to
PgStat_StatTabEntry.
Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Sami Imseih <samimseih@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/aN8l182jKxEq1h9f@paquier.xyz
Stats kinds can set a new option called "track_entry_count" (disabled by
default, available for variable-numbered stats) that will make pgstats
track the number of entries that exist in its shared hashtable.
As there is only one code path where a new entry is added, and one code
path where entries are freed, the count tracking is straight-forward in
its implementation. Reads of these counters are optimistic, and may
change across two calls. The counter is incremented when an entry is
created (not when reused), and is decremented when an entry is freed
from the hashtable (marked for drop with its refcount reaching 0), which
is something that pgstats decides internally.
A first use case of this facility would be pg_stat_statements, where we
need to be able to cap the number of entries that would be stored in the
shared hashtable, based on its "max" GUC. The module currently relies
on hash_get_num_entries(), which offers a cheap way to count how many
entries are in its hash table, but we cannot do that in pgstats for
variable-sized stats kinds as a single hashtable is used for all the
stats kinds. Independently of PGSS, this is useful for other custom
stats kinds that want to cap, control, or track the number of entries
they have, without depending on a potentially expensive sequential scan
to know the number of entries while holding an extra exclusive lock.
Author: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Sami Imseih <samimseih@gmail.com>
Reviewed-by: Keisuke Kuroda <keisuke.kuroda.3862@gmail.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/aMPKWR81KT5UXvEr@paquier.xyz
It had always been intended that this already works correctly as
pg_unreachable() uses __assume(0) on MSVC, and that directs the compiler
in a way so it knows that a given function won't return. However, with
ereport_domain(), it didn't work...
It's now understood that the failure to determine that elog(ERROR) does not
return comes from the inability of the MSVC compiler to detect the "const
int elevel_" is the same as the "elevel" macro parameter. MSVC seems to be
unable to make the "if (elevel_ >= ERROR) branch constantly-true when the
macro is used with any elevel >= ERROR, therefore the pg_unreachable() is
seen to only be present in a *conditional* branch rather than present
*unconditionally*.
While there seems to be no way to force the compiler into knowing that
elevel_ is equal to elevel within the ereport_domain() macro, there is a
way in C11 to determine if the elevel parameter is a compile-time
constant or not. This is done via some hackery using the _Generic()
intrinsic function, which gives us functionality similar to GCC's
__builtin_constant_p(), albeit only for integers.
Here we define pg_builtin_integer_constant_p() for this purpose.
Callers can check for availability via HAVE_PG_BUILTIN_INTEGER_CONSTANT_P.
ereport_domain() has been adjusted to use
pg_builtin_integer_constant_p() instead of __builtin_constant_p().
It's not quite clear at this stage if this now allows us to forego doing
the likes of "return NULL; /* keep compiler quiet */" as there may be other
compilers in use that have similar struggles. It's just a matter of time
before someone commits a function that does not "return" a value after
an elog(ERROR). Let's make time and lack of complaints about said commit
be the judge of if we need to continue the "/* keep compiler quiet */"
palaver.
Author: David Rowley <drowleyml@gmail.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/CAApHDvom02B_XNVSkvxznVUyZbjGAR+5myA89ZcbEd3=PA9UcA@mail.gmail.com
This change is a tighter rework of 7d85d87f4d, which tried to improve
the code so as it would work should PgStat_HashKey gain new fields that
create padding bytes. However, the previous change is proving to not be
enough as some code paths of pgstats do not pass PgStat_HashKey by
reference (valgrind would warn when padding is added to the structure,
through a new field).
Per discussion, let's document and check that PgStat_HashKey has no
padding rather than try to complicate the code of pgstats so as it is
able to work around that.
This removes a couple of memset(0) calls that should not be required.
While on it, this commit adds a static assertion checking that no
padding is introduced in the structure, by checking that the size of
PgStat_HashKey matches with the sum of the size of all its fields.
The object ID part of the hash key is already 8 bytes, which should be
plenty enough already. A comment is added to discourage the addition of
new fields.
Author: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Sami Imseih <samimseih@gmail.com>
Discussion: https://postgr.es/m/CAA5RZ0t9omat+HVSakJXwTMWvhpYFcAZb41RPWKwrKFUgmAFBQ@mail.gmail.com
This commit allows to log the raw parse tree in the same way we
currently log the parse tree, rewritten tree, and plan tree.
To avoid unnecessary log noise for users not interested in this
detail, a new GUC option, "debug_print_raw_parse", has been added.
When starting the PostgreSQL process with "-d N", and N is 3 or higher,
debug_print_raw_parse is enabled automatically, alongside
debug_print_parse.
Author: Chao Li <lic@highgo.com>
Reviewed-by: Tender Wang <tndrwang@gmail.com>
Reviewed-by: Tatsuo Ishii <ishii@postgresql.org>
Reviewed-by: John Naylor <johncnaylorls@gmail.com>
Discussion: https://postgr.es/m/CAEoWx2mcO0Gpo4vd8kPMAFWeJLSp0MeUUnaLdE1x0tSVd-VzUw%40mail.gmail.com
This commit changes some functions related to the data type numeric to
use the soft error reporting rather than a custom boolean flag (called
"have_error") that callers of these functions could rely on to bypass
the generation of ERROR reports, letting the callers do their own error
handling (timestamp, jsonpath and numeric_to_char() require them).
This results in the removal of some boilerplate code that was required
to handle both the ereport() and the "have_error" code paths bypassing
ereport(), unifying everything under the soft error reporting facility.
While on it, some duplicated error messages are removed. The function
upgraded in this commit were suffixed with "_opt_error" in their names.
They are renamed to "_safe" instead.
This change relies on d9f7f5d32f, that has introduced the soft error
reporting infrastructure.
Author: Amul Sul <sulamul@gmail.com>
Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com>
Discussion: https://postgr.es/m/CAAJ_b96No5h5tRuR+KhcC44YcYUCw8WAHuLoqqyyop8_k3+JDQ@mail.gmail.com
pg_lsn includes pg_lsn_in_internal() for the purpose of parsing a LSN
position for the GUC recovery_target_lsn (21f428ebde). It relies on a
boolean called "have_error" that would be set when the LSN parsing
fails, then let its callers handle any errors.
d9f7f5d32f has added support for soft error reporting. This commit
removes some boilerplate code and switches the routine to use soft error
reporting directly, giving to the callers of pg_lsn_in_internal()
the possibility to be fed the error message generated on failure.
pg_lsn_in_internal() routine is renamed to pg_lsn_in_safe(), for
consistency with other similar routines that are given an escontext.
Author: Amul Sul <sulamul@gmail.com>
Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com>
Discussion: https://postgr.es/m/CAAJ_b96No5h5tRuR+KhcC44YcYUCw8WAHuLoqqyyop8_k3+JDQ@mail.gmail.com
Store the information in guc_tables.c in a .dat file similar to the
catalog data in src/include/catalog/, and generate a part of
guc_tables.c from that. The goal is to make it easier to edit that
information, and to be able to make changes to the downstream data
structures more easily. (Essentially, those are the same reasons as
for the original adoption of the .dat format.)
Reviewed-by: John Naylor <johncnaylorls@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: David E. Wheeler <david@justatheory.com>
Discussion: https://www.postgresql.org/message-id/flat/dae6fe89-1e0c-4c3f-8d92-19d23374fb10%40eisentraut.org
This has been done historically because of get_database_name (which
since commit cb98e6fb8f belongs in lsyscache.c/h, so let's move it
there) and get_database_oid (which is in the right place, but whose
declaration should appear in pg_database.h rather than dbcommands.h).
Clean this up.
Also, xlogreader.h and stringinfo.h are no longer needed by dbcommands.h
since commit f1fd515b39, so remove them.
Author: Álvaro Herrera <alvherre@kurilemu.de>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/202508191031.5ipojyuaswzt@alvherre.pgsql
Commit 1585ff7387 changed GetTransactionSnapshot() to throw an error
if it's called during logical decoding, instead of returning the
historic snapshot. I made that change for extra protection, because a
historic snapshot can only be used to access catalog tables while
GetTransactionSnapshot() is usually called when you're executing
arbitrary queries. You might get very subtle visibility problems if
you tried to use the historic snapshot for arbitrary queries.
There's no built-in code in PostgreSQL that calls
GetTransactionSnapshot() during logical decoding, but it turns out
that the pglogical extension does just that, to evaluate row filter
expressions. You would get weird results if the row filter runs
arbitrary queries, but it is sane as long as you don't access any
non-catalog tables. Even though there are no checks to enforce that in
pglogical, a typical row filter expression does not access any tables
and works fine. Accessing tables marked with the user_catalog_table =
true option is also OK.
To fix pglogical with row filters, and any other extensions that might
do similar things, revert GetTransactionSnapshot() to return a
historic snapshot during logical decoding.
To try to still catch the unsafe usage of historic snapshots, add
checks in heap_beginscan() and index_beginscan() to complain if you
try to use a historic snapshot to scan a non-catalog table. We're very
close to the version 18 release however, so add those new checks only
in master.
Backpatch-through: 18
Reported-by: Noah Misch <noah@leadboat.com>
Reviewed-by: Noah Misch <noah@leadboat.com>
Discussion: https://www.postgresql.org/message-id/20250809222338.cc.nmisch@google.com
This code was relying on "long", which is signed 8 bytes everywhere
except on Windows where it is 4 bytes, that could potentially expose it
to overflows, even if the current uses in the code are fine as far as I
know. This code is now able to rely on the same sizeof() variable
everywhere, with int64. long was used for sizes, partition counts and
entry counts.
Some callers of the dynahash.c routines used long declarations, that can
be cleaned up to use int64 instead. There was one shortcut based on
SIZEOF_LONG, that can be removed. long is entirely removed from
dynahash.c and hsearch.h.
Similar work was done in b1e5c9fa9a.
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/aKQYp-bKTRtRauZ6@paquier.xyz
Previously this was being output to stderr. This commit adjusts things
to use elog(DEBUG4). Here we also adjust the format of the message to
add the hash table name and also put the message on a single line. This
should make grepping the logs for this information easier.
Also get rid of the global hash table statistics. This seems very dated
and didn't fit very well with trying to put all the statistics for a
specific hash table on a single log line.
The main aim here is to allow it so we can have at least one buildfarm
member build with HASH_STATISTICS to help prevent future changes from
breaking things in that area. ca3891251 recently fixed some issues
here.
In passing, switch to using uint64 data types rather than longs for the
usage counters. The long type is 32 bits on some platforms we support.
Author: David Rowley <dgrowleyml@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/CAApHDvoccvJ9CG5zx+i-EyCzJbcL5K=CzqrnL_YN59qaL5hiaw@mail.gmail.com
Remove conditionally-compiled code for smaller Datum widths,
and simplify comments that describe cases no longer of interest.
I also fixed up a few more places that were not using
DatumGetIntXX where they should, and made some cosmetic
adjustments such as using sizeof(int64) not sizeof(Datum)
in places where that fit better with the surrounding code.
One thing I remembered while preparing this part is that SP-GiST
stores pass-by-value prefix keys as Datums, so that the on-disk
representation depends on sizeof(Datum). That's even more
unfortunate than the existing commentary makes it out to be,
because now there is a hazard that the change of sizeof(Datum)
will break SP-GiST indexes on 32-bit machines. It appears that
there are no existing SP-GiST opclasses that are actually
affected; and if there are some that I didn't find, the number
of installations that are using them on 32-bit machines is
doubtless tiny. So I'm proceeding on the assumption that we
can get away with this, but it's something to worry about.
(gininsert.c looks like it has a similar problem, but it's okay
because the "tuples" it's constructing are just transient data
within the tuplesort step. That's pretty poorly documented
though, so I added some comments.)
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/1749799.1752797397@sss.pgh.pa.us
Commit e2d4ef8de8 (the fix for CVE-2017-7484) added security checks
to the selectivity estimation functions to prevent them from running
user-supplied operators on data obtained from pg_statistic if the user
lacks privileges to select from the underlying table. In cases
involving inheritance/partitioning, those checks were originally
performed against the child RTE (which for plain inheritance might
actually refer to the parent table). Commit 553d2ec271 then extended
that to also check the parent RTE, allowing access if the user had
permissions on either the parent or the child. It turns out, however,
that doing any checks using the child RTE is incorrect, since
securityQuals is set to NULL when creating an RTE for an inheritance
child (whether it refers to the parent table or the child table), and
therefore such checks do not correctly account for any RLS policies or
security barrier views. Therefore, do the security checks using only
the parent RTE. This is consistent with how RLS policies are applied,
and the executor's ACL checks, both of which use only the parent
table's permissions/policies. Similar checks are performed in the
extended stats code, so update that in the same way, centralizing all
the checks in a new function.
In addition, note that these checks by themselves are insufficient to
ensure that the user has access to the table's data because, in a
query that goes via a view, they only check that the view owner has
permissions on the underlying table, not that the current user has
permissions on the view itself. In the selectivity estimation
functions, there is no easy way to navigate from underlying tables to
views, so add permissions checks for all views mentioned in the query
to the planner startup code. If the user lacks permissions on a view,
a permissions error will now be reported at planner-startup, and the
selectivity estimation functions will not be run.
Checking view permissions at planner-startup in this way is a little
ugly, since the same checks will be repeated at executor-startup.
Longer-term, it might be better to move all the permissions checks
from the executor to the planner so that permissions errors can be
reported sooner, instead of creating a plan that won't ever be run.
However, such a change seems too far-reaching to be back-patched.
Back-patch to all supported versions. In v13, there is the added
complication that UPDATEs and DELETEs on inherited target tables are
planned using inheritance_planner(), which plans each inheritance
child table separately, so that the selectivity estimation functions
do not know that they are dealing with a child table accessed via its
parent. Handle that by checking access permissions on the top parent
table at planner-startup, in the same way as we do for views. Any
securityQuals on the top parent table are moved down to the child
tables by inheritance_planner(), so they continue to be checked by the
selectivity estimation functions.
Author: Dean Rasheed <dean.a.rasheed@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Noah Misch <noah@leadboat.com>
Backpatch-through: 13
Security: CVE-2025-8713
Recent ICU versions have added U_SHOW_CPLUSPLUS_HEADER_API, and we need
to set this to zero as well to hide the ICU C++ APIs from pg_locale.h
Per discussion, we want cpluspluscheck to work cleanly in backbranches,
so backpatch both this and its predecessor commit ed26c4e25a to all
supported versions.
Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/1115793.1754414782%40sss.pgh.pa.us
Backpatch-through: 13
These changes don't actually fix any leaks. They just make sure that
Valgrind will find pointers to data structures that remain allocated
at process exit, and thus not falsely complain about leaks. In
particular, we are trying to avoid situations where there is no
pointer to the beginning of an allocated block (except possibly
within the block itself, which Valgrind won't count).
* Because dynahash.c never frees hashtable storage except by deleting
the whole hashtable context, it doesn't bother to track the individual
blocks of elements allocated by element_alloc(). This results in
"possibly lost" complaints from Valgrind except when the first element
of each block is actively in use. (Otherwise it'll be on a freelist,
but very likely only reachable via "interior pointers" within element
blocks, which doesn't satisfy Valgrind.)
To fix, if we're building with USE_VALGRIND, expend an extra pointer's
worth of space in each element block so that we can chain them all
together from the HTAB header. Skip this in shared hashtables though:
Valgrind doesn't track those, and we'd need additional locking to make
it safe to manipulate a shared chain.
While here, update a comment obsoleted by 9c911ec06.
* Put the dlist_node fields of catctup and catclist structs first.
This ensures that the dlist pointers point to the starts of these
palloc blocks, and thus that Valgrind won't consider them
"possibly lost".
* The postmaster's PMChild structs and the autovac launcher's
avl_dbase structs also have the dlist_node-is-not-first problem,
but putting it first still wouldn't silence the warning because we
bulk-allocate those structs in an array, so that Valgrind sees a
single allocation. Commonly the first array element will be pointed
to only from some later element, so that the reference would be an
interior pointer even if it pointed to the array start. (This is the
same issue as for dynahash elements.) Since these are pretty simple
data structures, I don't feel too bad about faking out Valgrind by
just keeping a static pointer to the array start.
(This is all quite hacky, and it's not hard to imagine usages where
we'd need some other idea in order to have reasonable leak tracking of
structures that are only accessible via dlist_node lists. But these
changes seem to be enough to silence this class of leakage complaints
for the moment.)
* Free a couple of data structures manually near the end of an
autovacuum worker's run when USE_VALGRIND, and ensure that the final
vac_update_datfrozenxid() call is done in a non-permanent context.
This doesn't have any real effect on the process's total memory
consumption, since we're going to exit as soon as that last
transaction is done. But it does pacify Valgrind.
* Valgrind complains about the postmaster's socket-files and
lock-files lists being leaked, which we can silence by just
not nulling out the static pointers to them.
* Valgrind seems not to consider the global "environ" variable as
a valid root pointer; so when we allocate a new environment array,
it claims that data is leaked. To fix that, keep our own
statically-allocated copy of the pointer, similarly to the previous
item.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/285483.1746756246@sss.pgh.pa.us
When determining whether an allocated chunk is still reachable,
Valgrind will consider only pointers within what it believes to be
allocated chunks. Normally, all of a block obtained from malloc()
would be considered "allocated" --- but it turns out that if we use
VALGRIND_MEMPOOL_ALLOC to designate sub-section(s) of a malloc'ed
block as allocated, all the rest of that malloc'ed block is ignored.
This leads to lots of false positives of course. In particular,
in any multi-malloc-block context, all but the primary block were
reported as leaked. We also had a problem with context "ident"
strings, which were reported as leaked unless there was some other
pointer to them besides the one in the context header.
To fix, we need to use VALGRIND_MEMPOOL_ALLOC to designate
a context's management structs (the context struct itself and
any per-block headers) as allocated chunks. That forces moving
the VALGRIND_CREATE_MEMPOOL/VALGRIND_DESTROY_MEMPOOL calls into
the per-context-type code, so that the pool identifier can be
made as soon as we've allocated the initial block, but otherwise
it's fairly straightforward. Note that in Valgrind's eyes there
is no distinction between these allocations and the allocations
that the mmgr modules hand out to user code. That's fine for
now, but perhaps someday we'll want to do better yet.
When reading this patch, it's helpful to start with the comments
added at the head of mcxt.c.
Author: Andres Freund <andres@anarazel.de>
Co-authored-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/285483.1746756246@sss.pgh.pa.us
Discussion: https://postgr.es/m/20210317181531.7oggpqevzz6bka3g@alap3.anarazel.de
The callback added in fc415edf8c used to check if there is any pending
data to flush for fixed-numbered statistics, done by looping across all
the builtin and custom stats kinds with a call to have_fixed_pending_cb,
is proving to able to show in workloads that do not report any stats
(read-only, no function calls, no WAL, no IO, etc). The code used in
v17 was cheaper than that what HEAD has introduced, relying on three
boolean checks for WAL, SLRU and IO stats.
This commit switches the code to use a more efficient approach than
fc415edf8c, with a single boolean flag that can be switched to "true"
by any fixed-numbered stats kinds to force pgstat_report_stat() to go
through one round of reports. The flag is reset by pgstat_report_stat()
once a full round of reports is done. The flag being false means that
fixed-numbered stats kinds saw no activity, and that there is no pending
data to flush.
ac000fca74 took one step in improving the performance by reducing the
number of stats kinds that the backend can hold. This commit takes a
more drastic step by bringing back the code efficiency to what it was
before v18 with a cheap check at the beginning of pgstat_report_stat()
for its fast-exit path.
The callback have_static_pending_cb is removed as an effect of all that.
Reported-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://postgr.es/m/eb224uegsga2hgq7dfq3ps5cduhpqej7ir2hjxzzozjthrekx5@dysei6buqthe
Backpatch-through: 18
Commit 232d8caea fixed a case where postgres_fdw could lose track
of a PGresult object, resulting in a process-lifespan memory leak.
But I have little faith that there aren't other potential PGresult
leakages, now or in future, in the backend modules that use libpq.
Therefore, this patch proposes infrastructure that makes all
PGresults returned from libpq act as though they are palloc'd
in the CurrentMemoryContext (with the option to relocate them to
another context later). This should greatly reduce the risk of
careless leaks, and it also permits removal of a bunch of code
that attempted to prevent such leaks via PG_TRY blocks.
This patch adds infrastructure that wraps each PGresult in a
"libpqsrv_PGresult" that provides a memory context reset callback
to PQclear the PGresult. Code using this abstraction is inherently
memory-safe to the same extent as we are accustomed to in most backend
code. Furthermore, we add some macros that automatically redirect
calls of the libpq functions concerned with PGresults to use this
infrastructure, so that almost no source-code changes are needed to
wheel this infrastructure into place in all the backend code that
uses libpq.
Perhaps in future we could create similar infrastructure for
PGconn objects, but there seems less need for that.
This patch just creates the infrastructure and makes relevant code
use it, including reverting 232d8caea in favor of this mechanism.
A good deal of follow-on simplification is possible now that we don't
have to be so cautious about freeing PGresults, but I'll put that in
a separate patch.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Matheus Alcantara <matheusssilv97@gmail.com>
Discussion: https://postgr.es/m/2976982.1748049023@sss.pgh.pa.us
This commit changes stats kinds to have the following bounds, making
their handling in core cheaper by default:
- PGSTAT_KIND_CUSTOM_MIN 128 -> 24
- PGSTAT_KIND_MAX 256 -> 32
The original numbers were rather high, and showed an impact on
performance in pgstat_report_stat() for the case of simple queries with
its early-exit path if there are no pending statistics to flush. This
logic will be improved more in a follow-up commit to bring the
performance of pgstat_report_stat() on par with v17 and older versions.
Lowering the bounds is a change worth doing on its own, independently of
the other improvement.
These new numbers should be enough to leave some room for the following
years for built-in and custom stats kinds, with stable ID numbers. At
least that should be enough to start with this facility for extension
developers. It can be always increased in the tree depending on the
requirements wanted.
Per discussion with Andres Freund and Bertrand Drouvot.
Discussion: https://postgr.es/m/eb224uegsga2hgq7dfq3ps5cduhpqej7ir2hjxzzozjthrekx5@dysei6buqthe
Backpatch-through: 18
Previously, the check_hook functions for max_slot_wal_keep_size and
idle_replication_slot_timeout would incorrectly raise an ERROR for values
set in postgresql.conf during upgrade, even though those values were not
actively used in the upgrade process.
To prevent logical slot invalidation during upgrade, we used to set
special values for these GUCs. Now, instead of relying on those values, we
directly prevent WAL removal and logical slot invalidation caused by
max_slot_wal_keep_size and idle_replication_slot_timeout.
Note: PostgreSQL 17 does not include the idle_replication_slot_timeout
GUC, so related changes were not backported.
BUG #18979
Reported-by: jorsol <jorsol@gmail.com>
Author: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed by: vignesh C <vignesh21@gmail.com>
Reviewed by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Backpatch-through: 17, where it was introduced
Discussion: https://postgr.es/m/219561.1751826409@sss.pgh.pa.us
Discussion: https://postgr.es/m/18979-a1b7fdbb7cd181c6@postgresql.org
Previous commits invented timestamp2timestamptz_opt_overflow,
date2timestamp_opt_overflow, and date2timestamptz_opt_overflow
functions to perform non-error-throwing conversions between
datetime types. This patch completes the set by adding
timestamp2date_opt_overflow, timestamptz2date_opt_overflow,
and timestamptz2timestamp_opt_overflow.
In addition, adjust timestamp2timestamptz_opt_overflow so that it
doesn't throw error if timestamp2tm fails, but treats that as an
overflow case. The situation probably can't arise except with an
invalid timestamp value, and I can't think of a way that that would
happen except data corruption. However, it's pretty silly to have a
function whose entire reason for existence is to not throw errors for
out-of-range inputs nonetheless throw an error for out-of-range input.
The new APIs are not used in this patch, but will be needed in
upcoming btree_gin changes.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Arseniy Mukhin <arseniy.mukhin.dev@gmail.com>
Discussion: https://postgr.es/m/262624.1738460652@sss.pgh.pa.us
This routine has come as a useful piece to be able to know the list of
injection points currently attached in a system. One area would be to
use it in a set-returning function, or just let out-of-core code play
with it.
This hides the internals of the shared memory array lookup holding the
information about the injection points (point name, library and function
name), allocating the result in a palloc'd List consumable by the
caller.
Reviewed-by: Jeff Davis <pgsql@j-davis.com>
Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Rahila Syed <rahilasyed90@gmail.com>
Discussion: https://postgr.es/m/Z_xYkA21KyLEHvWR@paquier.xyz
Discussion: https://postgr.es/m/aBG2rPwl3GE7m1-Q@paquier.xyz
Presently, the dynamic shared memory (DSM) registry only provides
GetNamedDSMSegment(), which allocates a fixed-size segment. To use
the DSM registry for more sophisticated things like dynamic shared
memory areas (DSAs) or a hash table backed by a DSA (dshash), users
need to create a DSM segment that stores various handles and LWLock
tranche IDs and to write fairly complicated initialization code.
Furthermore, there is likely little variation in this
initialization code between libraries.
This commit introduces functions that simplify allocating a DSA or
dshash within the DSM registry. These functions are very similar
to GetNamedDSMSegment(). Notable differences include the lack of
an initialization callback parameter and the prohibition of calling
the functions more than once for a given entry in each backend
(which should be trivially avoidable in most circumstances). While
at it, this commit bumps the maximum DSM registry entry name length
from 63 bytes to 127 bytes.
Also note that even though one could presumably detach/destroy the
DSAs and dshashes created in the registry, such use-cases are not
yet well-supported, if for no other reason than the associated DSM
registry entries cannot be removed. Adding such support is left as
a future exercise.
The test_dsm_registry test module contains tests for the new
functions and also serves as a complete usage example.
Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Reviewed-by: Sami Imseih <samimseih@gmail.com>
Reviewed-by: Florents Tselai <florents.tselai@gmail.com>
Reviewed-by: Rahila Syed <rahilasyed90@gmail.com>
Discussion: https://postgr.es/m/aEC8HGy2tRQjZg_8%40nathan
