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Fix two bugs in archive_mode=shared on standby#84

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Fix two bugs in archive_mode=shared on standby#84
x4m wants to merge 54 commits into
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fix_sa_16

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@x4m x4m commented Apr 21, 2026

  1. Checkpoint on standby deletes WAL with .ready status. XLogArchiveCheckDone() treated archive_mode=shared like archive_mode=on during recovery, returning true unconditionally and allowing checkpoint to remove WAL segments that the primary had not yet archived. Fix: exclude shared mode from the early-return path, same as "always".

  2. Walsender never sends archival status reports after archiving is restored. WalSndArchivalReport() calls pgstat_fetch_stat_archiver() whose result is cached per-session (PGSTAT_FETCH_CONSISTENCY_CACHE by default). The walsender has no transaction boundaries that would clear the cache, so last_archived_wal remained "" forever, and strcmp() suppressed all reports. Fix: call pgstat_clear_snapshot() before fetching archiver stats.

Add TAP tests in 051_archive_shared_checkpoint.pl that reproduce both bugs, and extend 050_archive_shared.pl with checkpoint/restore scenarios.

x4m and others added 30 commits April 17, 2026 08:23
Currently we allow to cancel awaiting of syncronous commit.
Some drivers cancel query after timeout. If application will retry
idempotent query, it will get confirmation of written data.
This can lead to split-brain in HA scenarios. To prevent it this
we add synchronous_commit_cancelation setting disalowing cancelation
of syncronous replication wait

Version for PostgreSQL 16
Introduces 3 functions:
extern bool mdb_admin_allow_bypass_owner_checks(Oid userId,  Oid ownerId);
extern void check_mdb_admin_is_member_of_role(Oid member, Oid role);
extern bool mdb_admin_is_member_of_role(Oid member, Oid role);

To check mdb admin belongship and role-to-role ownership transfer
correctness.

Our mdb_admin ACL model is the following:

* Any roles user or/and roles can be granted with mdb_admin
* mdb_admin member can tranfser ownershup of relations,
namespaces and functions to other roles, if target role in neither:
superuser, pg_read_server_files, pg_write_server_files nor
pg_execute_server_program.

* Allow mdb_admin to create LEAKPROOF functions
* mdb admin sets session replication role
* [MDB-16648 + MDB-17910]: Allow mdb admin to kill specific superuser queries

MDB-27288: allow mdb_admin to kill autovac + tests

mdb-27228: fix expected output
MDB replication role regression tests

Patch allows user with mdb_replication role to use
pg_create_logical_replication_slot, pg_replication_slot_advance,
pg_drop_replication_slot functions to manage logical replication slots.
Also, users with mdb_admin (which is memner of pg_create_subscription)
can create subscribptions. Slot names starting with MDB.* are forbidden.

Add run as owner tap tests

More test cases in mdb_102
This commit introduces new mdb internal role mdb_superuser.

Role is capaple of:

GRANT/REVOKE any set of priviledges to/from any object in database.
Has power of pg_database_owner in any database, including:
DROP any object in database (except system catalog and stuff)

Role is NOT capaple of:

Create database, role, extension or alter other roles with such
priviledges.

Transfer ownership to /pass has_priv of roles:

PG_READ_ALL_DATA
PG_WRITE_ALL_DATA
PG_EXECUTE_SERVER_PROGRAM
PG_READ_SERVER_FILES
PG_WRITE_SERVER_FILES

Fix configure.ac USE_MDBLOCALES option handling

Apply autoreconf stuff

Set missing ok parameter ito true while acquiring mdb_superuser oid

In regress tests, nobody creates mdb_superuser role, so missing ok is
fine

Fix spelling

Applied suggestion

Allow mdb_superuser to have power of pg_database_owner

Allow mdb_superuser to alter objects and grant ACl to
objects, owned by pg_database_owner. Also, when acl check,
allow mdb_superuser use pg_database_owner role power to pass check

regression test fixes
… non-superuser

It is well known that some of PostgreSQL-related security issues (CVE)
was related to COPY FROM/TO PROGRAM exploits for priviledge escalation
or other unwanted behaviour or consequences. Thus, proper usage of
this feature needed. For now, simply forbit this.

Add mdb copy test
Do not use mdb_locales and mdb_newlocale when configured without them.

Added ifdef codepath build without mdb-locales feature

Add mdb locales patch, restore COPY from/to files, enable regress.

Squashed commit of the following:

commit 9f8ea4a5f42e0fd6077061bafbb428e88499896f
Author: reshke kirill <reshke@double.cloud>
Date:   Wed Feb 22 09:27:53 2023 +0000

    Add mdb locales patch, restore COPY from/to files, enable regress.

    This commit does several things.
    * Enables back COPY from/to FILE functionality, becuase it is used
    by pg_regress
    * Enables pg_regress tests in deb build itself.
    * Add mdb locales function and checks that package build with
    mdb-locales support

Add configure ac target to define USE_MDBLOCALES properly

Refactor optional setlocale, fix minor issues
Accept new startup param _pq_.service_auth_role for service auth under
any user, which is niether superuser nor have some dangerous system
role priv

Add tap-test for mdb service role auth 👍👌😉

Fix tests after rebase

contrib tests 💅️️💅️️💅️️ now works

MDB-23247: debug ouput for testing purposes lowered to DEBUG5 elog level

Skip caching routines for pre-startup logic (SCRAM -service auth role)
Update mdb-patched.md

Update mdb-pacthes.md
Merge in MDB/postgres-dev from MDB-24221 to MDB_15_STABLE

Squashed commit of the following:

commit 16d1cd273560f2f9df6b4e7e1b21f8a8667e6c29
Author: Dmitry S. Fedorov <fedusia@yandex-team.ru>
Date:   Thu Jul 13 11:14:19 2023 +0300

    MDB-24221: added support for jammy

commit 12f75e39ee084e7ff54297729d7f4162c80e5b22
Author: Dmitry S. Fedorov <fedusia@yandex-team.ru>
Date:   Thu Jul 13 11:14:19 2023 +0300

    MDB-24221: added support for jammy

Add docker entrypoint and util script

Add prepare-build script

enable tests
Fixes for mdb build to compile: disable gss

Build fix
Add test for drop database MDB behaviour
We learned from the field incidents, that 128Kb is not enough.
This time we are going to try to increase this value.
There is no need to log the entire query, because it may be large and take lots of space on disk. Parameter max_log_size set the maximum length for logged query. Everything beyond that length is truncated. Value 0 disables the parameter.
Merge in MDB/postgres-dev from MDB-31374-bump-llvm-18-pg16_4 to MDB_16_4_no_force

Squashed commit of the following:

commit fac6ac32dda9ca581ed17134cf67db5755144386
Author: Andrey Lyarskiy <aslyarskiy@yandex-team.ru>
Date:   Tue Oct 29 12:59:04 2024 +0300

    bump llvm to 18
Add new parameter to VACUUM command, FORCE, meaning VACUUM should
terminate all backends that prevents the execution by holding conflicting lock
remove bogus progress reporting
Also truncate query to be logged in simple query

Remove unused functions in buf_internals.h
Do not run mdb locales tests in OS

Add llvm dir

tmp
reshke and others added 24 commits April 17, 2026 08:23
* check-world in worlfows

* Run both check & check-world
In the case of a large PGSS_TEXT_FILE, the work time of the qtext_load_file
function will be quite long, and the query to the pg_stat_statements table
will not be cancellable, as there is no CHECK_FOR_INTERRUPT in the function.

Also, the amount of bytes read can reach 1 GB, which leads to a slow read
system call that does not allow cancellation of the query. Testing the speed
of sequential read using fio with different block sizes shows that there is
no significant difference between 16 MB blocks and 1 GB blocks.

Therefore, this patch changes the maximum read value from 1 GB to 16 MB and
adds INTERRUPTS_PENDING_CONDITION() check in the read loop of qtext_load_file to make it cancellable.
For now, only statement execution is cancellable (fail_on_interrupt is true only for calls from pg_stat_statements_internal)

Signed-off-by: rkhapov <r.khapov@ya.ru>
Reviewed-by: reshke <reshke@double.cloud>
Various parts of pg_dump consult the --schema-only and --data-only
options to determine whether to run a section of code.  While this
is simple enough for two mutually-exclusive options, it will become
progressively more complicated as more options are added.  In
anticipation of that, this commit introduces new internal flags
called dumpSchema and dumpData, which are derivatives of
--schema-only and --data-only.  This commit also removes the
schemaOnly and dataOnly members from the dump/restore options
structs to prevent their use elsewhere.

Note that this change neither adds new user-facing command-line
options nor changes the existing --schema-only and --data-only
options.

Author: Corey Huinker
Reviewed-by: Jeff Davis
Discussion: https://postgr.es/m/CADkLM%3DcQgghMJOS8EcAVBwRO4s1dUVtxGZv5gLPfZkQ1nL1gzA%40mail.gmail.com
Introduce a new archive_mode setting "shared" to prevent WAL history
loss during standby promotion in HA streaming replication setups.

In shared mode, the primary proactively sends archival status updates
to standbys via the replication protocol. The standby creates .ready
files for received WAL segments but defers marking them as .done until
the primary confirms archival. This prevents WAL from being recycled
before it's safely archived, addressing a critical gap in PITR continuity
during failover.

Key implementation details:

- Primary periodically sends last archived WAL segment via new
  PqReplMsg_ArchiveStatusReport ('a') message
- Standby marks all segments <= reported segment as .done using
  alphanumeric comparison on segment part (timeline-safe)
- Archiver skips during recovery in shared mode, activates on promotion
- Cascading replication: each standby coordinates with immediate upstream
- Startup check rejects archive_mode=on during recovery

This "push" design (primary sends status) is more efficient than "pull"
(standby queries per-segment), avoiding directory scans and stat() calls.
Based on Heikki Linnakangas's 2014 design and Greenplum's production
implementation, modernized for PostgreSQL 19.

Includes TAP tests covering basic synchronization, promotion,
cascading replication, and multiple standbys scenarios.
When standby receives archive status report, check if .ready files
belong to ancestor timelines before the switch point and mark them
as .done if already archived by primary.
When archive status reports arrive sequentially on the same timeline,
directly generate expected WAL filenames and mark them as archived
instead of scanning the entire archive_status directory.

This optimization reduces overhead in the common case where the primary
continuously archives segments. Directory scan is still used when:
- Timeline changes (to handle ancestor timelines)
- First report received
- Non-sequential reports

XLogArchiveForceDone() handles all cases internally (checking if .done
exists, if .ready exists, or creating .done if neither exists), so no
pre-check is needed.
XXX do we also need DROP OWNED to work this way? Probably not.

Author: Alvaro Herrera

Discussion: https://postgr.es/m/CALdSSPhjONb+EftRD=J1pqajkB+pjT0=tbMJs16C6q9+xT8NNg@mail.gmail.com
This commit adds timeout that is expected to be used as a prevention
of long-running queries. Any session within the transaction will be
terminated after spanning longer than this timeout.

However, this timeout is not applied to prepared transactions.
Only transactions with user connections are affected.


Don't deal with transaction timeout in PostgresMain().  Instead, release
transaction timeout activated by StartTransaction() in
CommitTransaction()/AbortTransaction()/PrepareTransaction().  Deal with both
enabling and disabling transaction timeout in assign_transaction_timeout().

Also, remove potentially flaky timeouts-long isolation test, which has no
guarantees to pass on slow/busy machines.

Discussion: https://postgr.es/m/20240215230856.pc6k57tqxt7fhldm%40awork3.anarazel.de
Discussion: https://postgr.es/m/CAAhFRxiQsRs2Eq5kCo9nXE3HTugsAAJdSQSmxncivebAxdmBjQ%40mail.gmail.com
Author: Andrey Borodin <amborodin@acm.org>
Author: Japin Li <japinli@hotmail.com>
Author: Junwang Zhao <zhjwpku@gmail.com>

Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: bt23nguyent <bt23nguyent@oss.nttdata.com>
Reviewed-by: Yuhang Qiu <iamqyh@gmail.com>

Backport-by: rkhapov <r.khapov@ya.ru> 
Reviewed-by: reshke <reshke@double.cloud>

===== 
Cherry-pick source: 51efe38 bf82f43
1. Checkpoint on standby deletes WAL with .ready status.
   XLogArchiveCheckDone() treated archive_mode=shared like archive_mode=on
   during recovery, returning true unconditionally and allowing checkpoint
   to remove WAL segments that the primary had not yet archived.
   Fix: exclude shared mode from the early-return path, same as "always".

2. Walsender never sends archival status reports after archiving is restored.
   WalSndArchivalReport() calls pgstat_fetch_stat_archiver() whose result is
   cached per-session (PGSTAT_FETCH_CONSISTENCY_CACHE by default).  The
   walsender has no transaction boundaries that would clear the cache, so
   last_archived_wal remained "" forever, and strcmp() suppressed all reports.
   Fix: call pgstat_clear_snapshot() before fetching archiver stats.

Add TAP tests in 051_archive_shared_checkpoint.pl that reproduce both bugs,
and extend 050_archive_shared.pl with checkpoint/restore scenarios.
@reshke reshke force-pushed the MDB_16_STABLE branch 2 times, most recently from 7edaea5 to c7f9a1e Compare April 29, 2026 09:41
@reshke reshke force-pushed the MDB_16_STABLE branch 2 times, most recently from 95c1852 to 3b9643a Compare May 11, 2026 19:47
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9 participants