Previously, the DSA segment size always started with 1MB and grew up
to DSA_MAX_SEGMENT_SIZE. It was inconvenient in certain scenarios,
such as when the caller desired a soft constraint on the total DSA
segment size, limiting it to less than 1MB.
This commit introduces the capability to specify the initial and
maximum DSA segment sizes when creating a DSA area, providing more
flexibility and control over memory usage.
Reviewed-by: John Naylor, Tomas Vondra
Discussion: https://postgr.es/m/CAD21AoAYGGC1ePjVX0H%2Bpp9rH%3D9vuPK19nNOiu12NprdV5TVJA%40mail.gmail.com
Commit e2fa76d80 centralized the responsibility for doing
set_cheapest() for a baserel, but these functions added later
seemingly didn't get the memo. There's no apparent reason why
we need the cheapest path for these relation types to be available
any sooner than it is for other base relation types, so delete the
duplicate calls. Doesn't save much since there's only one path
in these cases, but it might improve clarity.
Richard Guo
Discussion: https://postgr.es/m/CAMbWs4-KFEU_fDuJPNCOkUu3rwvZvKBEytkd9VrM4kH4-2h1CQ@mail.gmail.com
When the list of roles gathered by roles_is_member_of() grows very
large, a Bloom filter is created to help avoid some linear searches
through the list. The threshold for creating the Bloom filter is
set arbitrarily high and may require future adjustment.
Suggested-by: Tom Lane
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/CAGvXd3OSMbJQwOSc-Tq-Ro1CAz%3DvggErdSG7pv2s6vmmTOLJSg%40mail.gmail.com
Ordinary ALTER TABLE SET SCHEMA will also move any owned sequences
into the new schema. We failed to do likewise for foreign tables,
because AlterTableNamespaceInternal believed that only certain
relkinds could have indexes, owned sequences, or constraints.
We could simply add foreign tables to that relkind list, but it
seems likely that the same oversight could be made again in
future. Instead let's remove the relkind filter altogether.
These functions shouldn't cost much when there are no objects
that they need to process, and surely this isn't an especially
performance-critical case anyway.
Per bug #18407 from Vidushi Gupta. Back-patch to all supported
branches.
Discussion: https://postgr.es/m/18407-4fd07373d252c6a0@postgresql.org
If we know the sort order of a CTE's output, and it is relevant
to the outer query, label the CTE's outer-query access path using
those pathkeys. This may enable optimizations such as avoiding
a sort in the outer query.
The code for hoisting pathkeys into the outer query already exists
for regular RTE_SUBQUERY subqueries, but it wasn't getting used for
CTEs, possibly out of concern for maintaining an optimization fence
between the CTE and the outer query. However, on the same arguments
used for commit f7816aec2, there seems no harm in letting the outer
query know what the inner query decided to do.
In support of this, we now remember the best Path as well as Plan
for each subquery for the rest of the planner run. There may be
future applications for having that at hand, and it surely costs
little to build one more List.
Richard Guo (minor mods by me)
Discussion: https://postgr.es/m/CAMbWs49xYd3f8CrE8-WW3--dV1zH_sDSDn-vs2DzHj81Wcnsew@mail.gmail.com
The musl dynamic linker saves a pointer to the process' environment
value of LD_LIBRARY_PATH very early in startup. When we move/clobber
the environment to make more room for ps status strings, we clobber
that value and thereby prevent libraries from being found via
LD_LIBRARY_PATH, which breaks the use of a temporary installation
for testing purposes. To fix, stop collecting usable space for
ps status if we notice that the variable we are about to clobber
is LD_LIBRARY_PATH. This will result in some reduction in how long
the ps status can be, but it's only likely to occur in temporary
test contexts, so it doesn't seem like a big problem. In any case,
we don't have to do it if we see we are on glibc, which surely is
where the majority of our Linux testing is done.
Thomas Munro, Bruce Momjian, and Tom Lane, per report from Wolfgang
Walther. Back-patch to all supported branches, with the hope that
we'll set up a buildfarm animal to test on this platform.
Discussion: https://postgr.es/m/fddd1cd6-dc16-40a2-9eb5-d7fef2101488@technowledgy.de
ObjectClass is an enum whose values correspond to catalog OIDs. But
the extra layer of redirection, which is used only in small parts of
the code, and the similarity to ObjectType, are confusing and
cumbersome.
One advantage has been that some switches processing the OCLASS enum
don't have "default:" cases. This is so that the compiler tells us
when we fail to add support for some new object class. But you can
also handle that with some assertions and proper test coverage. It's
not even clear how strong this benefit is. For example, in
AlterObjectNamespace_oid(), you could still put a new OCLASS into the
"ignore object types that don't have schema-qualified names" case, and
it might or might not be wrong. Also, there are already various
OCLASS switches that do have a default case, so it's not even clear
what the preferred coding style should be.
Reviewed-by: jian he <jian.universality@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://www.postgresql.org/message-id/flat/CAGECzQT3caUbcCcszNewCCmMbCuyP7XNAm60J3ybd6PN5kH2Dw%40mail.gmail.com
Currently, in read committed transaction isolation mode (default), we have the
following sequence of actions when tuple_update()/tuple_delete() finds
the tuple updated by the concurrent transaction.
1. Attempt to update/delete tuple with tuple_update()/tuple_delete(), which
returns TM_Updated.
2. Lock tuple with tuple_lock().
3. Re-evaluate plan qual (recheck if we still need to update/delete and
calculate the new tuple for update).
4. Second attempt to update/delete tuple with tuple_update()/tuple_delete().
This attempt should be successful, since the tuple was previously locked.
This commit eliminates step 2 by taking the lock during the first
tuple_update()/tuple_delete() call. The heap table access method saves some
effort by checking the updated tuple once instead of twice. Future
undo-based table access methods, which will start from the latest row version,
can immediately place a lock there.
Also, this commit makes tuple_update()/tuple_delete() optionally save the old
tuple into the dedicated slot. That saves efforts on re-fetching tuples in
certain cases.
The code in nodeModifyTable.c is simplified by removing the nested switch/case.
Discussion: https://postgr.es/m/CAPpHfdua-YFw3XTprfutzGp28xXLigFtzNbuFY8yPhqeq6X5kg%40mail.gmail.com
Reviewed-by: Aleksander Alekseev, Pavel Borisov, Vignesh C, Mason Sharp
Reviewed-by: Andres Freund, Chris Travers
Put the node-type-dependent operations into switches on nodeTag.
This should ease addition of new proof rules for other expression
node types. There is no functional change, although some tests
are made in a different order than before.
Also, add a couple of new cross-checks in test_predtest.c.
James Coleman (part of a larger patch series)
Discussion: https://postgr.es/m/CAAaqYe8Bo4bf_i6qKj8KBsmHMYXhe3Xt6vOe3OBQnOaf3_XBWg@mail.gmail.com
It's now possible to specify a table access method via
CREATE TABLE ... USING for a partitioned table, as well change it with
ALTER TABLE ... SET ACCESS METHOD. Specifying an AM for a partitioned
table lets the value be used for all future partitions created under it,
closely mirroring the behavior of the TABLESPACE option for partitioned
tables. Existing partitions are not modified.
For a partitioned table with no AM specified, any new partitions are
created with the default_table_access_method.
Also add ALTER TABLE ... SET ACCESS METHOD DEFAULT, which reverts to the
original state of using the default for new partitions.
The relcache of partitioned tables is not changed: rd_tableam is not
set, even if a partitioned table has a relam set.
Author: Justin Pryzby <pryzby@telsasoft.com>
Author: Soumyadeep Chakraborty <soumyadeep2007@gmail.com>
Author: Michaël Paquier <michael@paquier.xyz>
Reviewed-by: The authors themselves
Discussion: https://postgr.es/m/CAE-ML+9zM4wJCGCBGv01k96qQ3gFv4WFcFy=zqPHKeaEFwwv6A@mail.gmail.com
Discussion: https://postgr.es/m/20210308010707.GA29832%40telsasoft.com
The new combined WAL record is now used for pruning, freezing and 2nd
pass of vacuum. This is in preparation for changing VACUUM to write a
combined prune+freeze record per page, instead of separate two
records. The new WAL record format now supports that, but the code
still always writes separate records for pruning and freezing.
This reserves separate XLOG_HEAP2_* info codes for when the pruning
record is emitted for on-access pruning or VACUUM, per Peter
Geoghegan's suggestion. The record format is identical, but having
separate info codes makes it easier analyze pruning and vacuuming with
pg_waldump.
The function to emit the new WAL record, log_heap_prune_and_freeze(),
is in pruneheap.c. The existing heap_log_freeze_plan() and its
subroutines are moved to pruneheap.c without changes, to keep them
together with log_heap_prune_and_freeze().
Author: Melanie Plageman <melanieplageman@gmail.com>
Discussion: https://www.postgresql.org/message-id/CAAKRu_azf-zH%3DDgVbquZ3tFWjMY1w5pO8m-TXJaMdri8z3933g@mail.gmail.com
Discussion: https://www.postgresql.org/message-id/CAAKRu_b2oE4GL%3Dq4g9mcByS9yT7wTQvEH9OLpabj28e%2BWKFi2A@mail.gmail.com
This commit adds a new property called last_inactive_time for slots. It is
set to 0 whenever a slot is made active/acquired and set to the current
timestamp whenever the slot is inactive/released or restored from the disk.
Note that we don't set the last_inactive_time for the slots currently being
synced from the primary to the standby because such slots are typically
inactive as decoding is not allowed on those.
The 'last_inactive_time' will be useful on production servers to debug and
analyze inactive replication slots. It will also help to know the lifetime
of a replication slot - one can know how long a streaming standby, logical
subscriber, or replication slot consumer is down.
The 'last_inactive_time' will also be useful to implement inactive
timeout-based replication slot invalidation in a future commit.
Author: Bharath Rupireddy
Reviewed-by: Bertrand Drouvot, Amit Kapila, Shveta Malik
Discussion: https://www.postgresql.org/message-id/CALj2ACW4aUe-_uFQOjdWCEN-xXoLGhmvRFnL8SNw_TZ5nJe+aw@mail.gmail.com
Specifically, this commit reduces the memory consumed by the
SpecialJoinInfos that are allocated for child joins in
try_partitionwise_join() by freeing them at the end of creating paths
for each child join.
A SpecialJoinInfo allocated for a given child join is a copy of the
parent join's SpecialJoinInfo, which contains the translated copies
of the various Relids bitmapsets and semi_rhs_exprs, which is a List
of Nodes. The newly added freeing step frees the struct itself and
the various bitmapsets, but not semi_rhs_exprs, because there's no
handy function to free the memory of Node trees.
Author: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Richard Guo <guofenglinux@gmail.com>
Reviewed-by: Amit Langote <amitlangote09@gmail.com>
Reviewed-by: Andrey Lepikhov <a.lepikhov@postgrespro.ru>
Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com>
Discussion: https://postgr.es/m/CAExHW5tHqEf3ASVqvFFcghYGPfpy7o3xnvhHwBGbJFMRH8KjNw@mail.gmail.com
Until now, UNION queries have often been suboptimal as the planner has
only ever considered using an Append node and making the results unique
by either using a Hash Aggregate, or by Sorting the entire Append result
and running it through the Unique operator. Both of these methods
always require reading all rows from the union subqueries.
Here we adjust the union planner so that it can request that each subquery
produce results in target list order so that these can be Merge Appended
together and made unique with a Unique node. This can improve performance
significantly as the union child can make use of the likes of btree
indexes and/or Merge Joins to provide the top-level UNION with presorted
input. This is especially good if the top-level UNION contains a LIMIT
node that limits the output rows to a small subset of the unioned rows as
cheap startup plans can be used.
Author: David Rowley
Reviewed-by: Richard Guo, Andy Fan
Discussion: https://postgr.es/m/CAApHDvpb_63XQodmxKUF8vb9M7CxyUyT4sWvEgqeQU-GB7QFoQ@mail.gmail.com
Up to now we've rejected cases like
BEGIN;
CREATE TYPE rainbow AS ENUM ();
ALTER TYPE rainbow ADD VALUE 'red';
-- use the value 'red', perhaps in a constraint or index
COMMIT;
The concern is that the uncommitted enum value 'red' might get into
an index and then break the index if we roll back the ALTER ADD.
If the ALTER is in the same transaction as the CREATE then it's really
perfectly safe, but we weren't taking the trouble to identify that.
pg_dump in binary-upgrade mode will emit enum definitions that look
like the above, which up to now didn't fall foul of the unsafe-usage
check because we processed each restore command as a separate
transaction. However an upcoming patch proposes to bundle the restore
commands into large transactions to reduce XID consumption during
pg_upgrade, and that makes this behavior a problem.
To fix, remember the OIDs of enum types created in the current
transaction, and allow use of enum values that are added to one later
in the same transaction. To do this fully correctly in the presence
of subtransactions, we'd have to track subtransaction nesting level of
the CREATE and do maintenance work at every subsequent subtransaction
exit. That seems expensive, and we don't need it to satisfy pg_dump's
usage. Hence, apply the additional optimization only when the CREATE
and ALTER are at outermost transaction level.
Patch by me, reviewed by Andrew Dunstan
Discussion: https://postgr.es/m/1548468.1711220438@sss.pgh.pa.us
Add PERIOD clause to foreign key constraint definitions. This is
supported for range and multirange types. Temporal foreign keys check
for range containment instead of equality.
This feature matches the behavior of the SQL standard temporal foreign
keys, but it works on PostgreSQL's native ranges instead of SQL's
"periods", which don't exist in PostgreSQL (yet).
Reference actions ON {UPDATE,DELETE} {CASCADE,SET NULL,SET DEFAULT}
are not supported yet.
Author: Paul A. Jungwirth <pj@illuminatedcomputing.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: jian he <jian.universality@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CA+renyUApHgSZF9-nd-a0+OPGharLQLO=mDHcY4_qQ0+noCUVg@mail.gmail.com
Up to now, all of the "catcache list" objects within a catalog cache
were just chained together on a single dlist, requiring O(N) time to
search. Remarkably, we've not had serious performance problems with
that so far; but we got a complaint of a bad performance regression
from v15 in a case with a large number of roles in the system, which
traced down to O(N^2) total time when we probed N catcache lists.
Replace that data structure with a hashtable having an enlargeable
number of dlists, in an exactly parallel way to the data structure
we've used for years for the plain CatCTup cache members. The extra
cost of maintaining a hash table seems negligible, since we were
already computing a hash value for list searches.
Normally this'd be HEAD-only material, but in view of the performance
regression it seems advisable to back-patch into v16. In the v16
version of the patch, leave the dead cc_lists field where it is and
add the new fields at the end of struct catcache, to avoid possible
ABI breakage in case any external code is looking at these structs.
(We assume no external code is actually allocating new catcache
structs.)
Per report from alex work.
Discussion: https://postgr.es/m/CAGvXd3OSMbJQwOSc-Tq-Ro1CAz=vggErdSG7pv2s6vmmTOLJSg@mail.gmail.com
This adds the X509 attributes notBefore and notAfter to sslinfo
as well as pg_stat_ssl to allow verifying and identifying the
validity period of the current client certificate. OpenSSL has
APIs for extracting notAfter and notBefore, but they are only
supported in recent versions so we have to calculate the dates
by hand in order to make this work for the older versions of
OpenSSL that we still support.
Original patch by Cary Huang with additional hacking by Jacob
and myself.
Author: Cary Huang <cary.huang@highgo.ca>
Co-author: Jacob Champion <jacob.champion@enterprisedb.com>
Co-author: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/182b8565486.10af1a86f158715.2387262617218380588@highgo.ca
This changes nodeToString() to not output the actual value of location
fields in nodes, but instead it writes -1. This mirrors the fact that
stringToNode() also does not read location field values but always
stores -1.
For most uses of nodeToString(), which is to store nodes in catalog
fields, this is more useful. We don't store original query texts in
catalogs, so any lingering query location values are not meaningful.
For debugging purposes, there is a new nodeToStringWithLocations(),
which mirrors the existing stringToNodeWithLocations(). This is used
for WRITE_READ_PARSE_PLAN_TREES and nodes/print.c functions, which
covers all the debugging uses.
Reviewed-by: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CAEze2WgrCiR3JZmWyB0YTc8HV7ewRdx13j0CqD6mVkYAW+SFGQ@mail.gmail.com
Till now, the reason for replication slot invalidation is not tracked
directly in pg_replication_slots. A recent commit 007693f2a3 added
'conflict_reason' to show the reasons for slot conflict/invalidation, but
only for logical slots.
This commit adds a new column 'invalidation_reason' to show invalidation
reasons for both physical and logical slots. And, this commit also turns
'conflict_reason' text column to 'conflicting' boolean column (effectively
reverting commit 007693f2a3). The 'conflicting' column is true for
invalidation reasons 'rows_removed' and 'wal_level_insufficient' because
those make the slot conflict with recovery. When 'conflicting' is true,
one can now look at the new 'invalidation_reason' column for the reason
for the logical slot's conflict with recovery.
The new 'invalidation_reason' column will also be useful to track other
invalidation reasons in the future commit.
Author: Bharath Rupireddy
Reviewed-by: Bertrand Drouvot, Amit Kapila, Shveta Malik
Discussion: https://www.postgresql.org/message-id/ZfR7HuzFEswakt/a%40ip-10-97-1-34.eu-west-3.compute.internal
Discussion: https://www.postgresql.org/message-id/CALj2ACW4aUe-_uFQOjdWCEN-xXoLGhmvRFnL8SNw_TZ5nJe+aw@mail.gmail.com
Put the fields alias and eref earlier in the struct, so that it
matches the order in _outRangeTblEntry()/_readRangeTblEntry(). This
helps if we ever want to fully automate out/read of RangeTblEntry.
Also, it makes dumps in the debugger easier to read in the same way.
Internally, this makes no difference.
Reviewed-by: Andrew Dunstan <andrew@dunslane.net>
Discussion: https://www.postgresql.org/message-id/flat/4b27fc50-8cd6-46f5-ab20-88dbaadca645@eisentraut.org
This is part of an effort to reduce the number of special cases in the
automatically generated node support functions.
This patch removes _jumbleRangeTblEntry() and instead adds per-field
query_jumble_ignore annotations to match the behavior of the previous
custom code. The pg_stat_statements test suite has some coverage of
this. It gets rid of the switch on rtekind; this should be
technically correct, since we do the equal and copy functions like
this also.
The list of fields to jumble has been checked and is considered
correct as of 8b29a119fd.
Reviewed-by: Andrew Dunstan <andrew@dunslane.net>
Discussion: https://www.postgresql.org/message-id/flat/4b27fc50-8cd6-46f5-ab20-88dbaadca645@eisentraut.org
This allows us to abstract how/whether table AM uses transaction identifiers.
A custom table AM can use a custom slot, which may not store xmin directly,
but determine the tuple belonging to the current transaction in the other way.
Discussion: https://postgr.es/m/CAPpHfdurb9ycV8udYqM%3Do0sPS66PJ4RCBM1g-bBpvzUfogY0EA%40mail.gmail.com
Reviewed-by: Matthias van de Meent, Mark Dilger, Pavel Borisov
Reviewed-by: Nikita Malakhov, Japin Li
This allows table AM to return a native tuple slot even if
VirtualTupleTableSlot is given as an input. Native tuple slots have knowledge
about system attributes, which could be accessed in the future.
table_multi_insert() method already can modify the input 'slots' array.
Discussion: https://postgr.es/m/CAPpHfdurb9ycV8udYqM%3Do0sPS66PJ4RCBM1g-bBpvzUfogY0EA%40mail.gmail.com
Reviewed-by: Matthias van de Meent, Mark Dilger, Pavel Borisov
Reviewed-by: Nikita Malakhov, Japin Li
The new table AM method free_rd_amcache is responsible for freeing all the
memory related to rd_amcache and setting free_rd_amcache to NULL. If the new
method is not specified, we still assume rd_amcache to be a single chunk of
memory, which could be just pfree'd.
Discussion: https://postgr.es/m/CAPpHfdurb9ycV8udYqM%3Do0sPS66PJ4RCBM1g-bBpvzUfogY0EA%40mail.gmail.com
Reviewed-by: Matthias van de Meent, Mark Dilger, Pavel Borisov
Reviewed-by: Nikita Malakhov, Japin Li
TIDStore is a data structure designed to efficiently store large sets
of TIDs. For TID storage, it employs a radix tree, where the key is
a block number, and the value is a bitmap representing offset
numbers. The TIDStore can be created on a DSA area and used by
multiple backend processes simultaneously.
There are potential future users such as tidbitmap.c, though it's very
likely the interface will need to evolve as we come to understand the
needs of different kinds of users. For example, we can support
updating the offset bitmap of existing values.
Currently, the TIDStore is not used for anything yet, aside from the
test code. But an upcoming patch will use it.
This includes a unit test module, in src/test/modules/test_tidstore.
Co-authored-by: John Naylor
Discussion: https://postgr.es/m/CAD21AoAfOZvmfR0j8VmZorZjL7RhTiQdVttNuC4W-Shdc2a-AA%40mail.gmail.com
This essentially reverts commit 69eb643b2, which added a fast path
in Catalog::ParseData, but neglected to preserve the behavior of
adding a line_number field in each hash. That makes it impossible
for genbki.pl to provide any localization of error reports, which is
bad enough; but actually the affected error reports failed entirely,
producing useless bleats like "use of undefined value in sprintf".
69eb643b2 claimed to get a 15% speedup, but I'm not sure I believe
that: the time to rebuild the bki files changes by less than 1% for
me. In any case, making debugging of mistakes in .dat files more
difficult would not be justified by even an order of magnitude
speedup here; it's just not that big a chunk of the total build time.
Per report from David Wheeler. Although it's also broken in v16,
I don't think this is worth a back-patch, since we're very unlikely
to touch the v16 catalog data again.
Discussion: https://postgr.es/m/19238.1710953049@sss.pgh.pa.us
In combination with to_regtype, this allows converting a string to
the "canonicalized" form emitted by format_type. That usage requires
parsing the string twice, which is slightly annoying but not really
too expensive. We considered alternatives such as returning a record
type, but that way was notationally uglier than this, and possibly
less flexible.
Like to_regtype(), we'd rather that this return NULL for any bad
input, but the underlying type-parsing logic isn't yet capable of
not throwing syntax errors. Adjust the documentation for both
functions to point that out.
In passing, fix up a couple of nearby entries in the System Catalog
Information Functions table that had not gotten the word about our
since-v13 convention for displaying function usage examples.
David Wheeler and Erik Wienhold, reviewed by Pavel Stehule, Jim Jones,
and others.
Discussion: https://postgr.es/m/DF2324CA-2673-4ABE-B382-26B5770B6AA3@justatheory.com
This commit limits the maximum value of wal_summary_keep_time to
INT_MAX / SECS_PER_MINUTE to avoid overflow when it is converted to
seconds. In passing, use the HOURS_PER_DAY, MINS_PER_HOUR, and
SECS_PER_MINUTE macros in the code for this GUC instead of hard-
coding those values.
Discussion: https://postgr.es/m/20240314210010.GA3056455%40nathanxps13
This way, we can fold the list of lock names to occur in
BuiltinTrancheNames instead of having its own separate array. This
saves two lines of code in GetLWTrancheName and some space in
BuiltinTrancheNames, as foreseen in commit 74a7306310, as well as
removing the need for a separate lwlocknames.c file.
We still have to build lwlocknames.h using Perl code, which initially I
wanted to avoid, but it gives us the chance to cross-check
wait_event_names.txt.
Discussion: https://postgr.es/m/202401231025.gbv4nnte5fmm@alvherre.pgsql
To avoid the compiler warnings:
launch_backend.c:211:39: warning: comparison of constant 16 with expression of type 'BackendType' (aka 'enum BackendType') is always true [-Wtautological-constant-out-of-range-compare]
launch_backend.c:233:39: warning: comparison of constant 16 with expression of type 'BackendType' (aka 'enum BackendType') is always true [-Wtautological-constant-out-of-range-compare]
The point of the assertions was to fail more explicitly if someone
adds a new BackendType to the end of the enum, but forgets to add it
to the child_process_kinds array. It was a pretty weak assertion to
begin with, because it wouldn't catch if you added a new BackendType
in the middle of the enum. So let's just remove it.
Per buildfarm member ayu and a few others, spotted by Tom Lane.
Discussion: https://www.postgresql.org/message-id/4119680.1710913067@sss.pgh.pa.us
The builtin C.UTF-8 locale has similar semantics to the libc locale of
the same name. That is, code point sort order (fast, memcmp-based)
combined with Unicode semantics for character operations such as
pattern matching, regular expressions, and
LOWER()/INITCAP()/UPPER(). The character semantics are based on
Unicode simple case mappings.
The builtin provider's C.UTF-8 offers several important advantages
over libc:
* faster sorting -- benefits from additional optimizations such as
abbreviated keys and varstrfastcmp_c
* faster case conversion, e.g. LOWER(), at least compared with some
libc implementations
* available on all platforms with identical semantics, and the
semantics are stable, testable, and documentable within a given
Postgres major version
Being based on memcmp, the builtin C.UTF-8 locale does not offer
natural language sort order. But it is an improvement for most use
cases that might otherwise use libc's "C.UTF-8" locale, as well as
many use cases that use libc's "C" locale.
Discussion: https://postgr.es/m/ff4c2f2f9c8fc7ca27c1c24ae37ecaeaeaff6b53.camel%40j-davis.com
Reviewed-by: Daniel Vérité, Peter Eisentraut, Jeremy Schneider
