Commit a4ccc1cef introduced the Generation Context and modified the
logical decoding process to use a Generation Context with a fixed
block size of 8MB for storing tuple data decoded during logical
decoding (i.e., rb->tup_context). Several reports have indicated that
the logical decoding process can be terminated due to
out-of-memory (OOM) situations caused by excessive memory usage in
rb->tup_context.
This issue can occur when decoding a workload involving several
concurrent transactions, including a long-running transaction that
modifies tuples. By design, the Generation Context does not free a
memory block until all chunks within that block are
released. Consequently, if tuples modified by the long-running
transaction are stored across multiple memory blocks, these blocks
remain allocated until the long-running transaction completes, leading
to substantial memory fragmentation. The memory usage during logical
decoding, tracked by rb->size, does not account for memory
fragmentation, resulting in potentially much higher memory consumption
than the value of the logical_decoding_work_mem parameter.
Various improvement strategies were discussed in the relevant
thread. This change reduces the block size of the Generation Context
used in rb->tup_context from 8MB to 8kB. This modification
significantly decreases the likelihood of substantial memory
fragmentation occurring and is relatively straightforward to
backport. Performance testing across multiple platforms has confirmed
that this change will not introduce any performance degradation that
would impact actual operation.
Backport to all supported branches.
Reported-by: Alex Richman, Michael Guissine, Avi Weinberg
Reviewed-by: Amit Kapila, Fujii Masao, David Rowley
Tested-by: Hayato Kuroda, Shlok Kyal
Discussion: https://postgr.es/m/CAD21AoBTY1LATZUmvSXEssvq07qDZufV4AF-OHh9VD2pC0VY2A%40mail.gmail.com
Backpatch-through: 12
We advance origin progress during abort on successful streaming and
application of ROLLBACK in parallel streaming mode. But the origin
shouldn't be advanced during an error or unsuccessful apply due to
shutdown. Otherwise, it will result in a transaction loss as such a
transaction won't be sent again by the server.
Reported-by: Hou Zhijie
Author: Hayato Kuroda and Shveta Malik
Reviewed-by: Amit Kapila
Backpatch-through: 16
Discussion: https://postgr.es/m/TYAPR01MB5692FAC23BE40C69DA8ED4AFF5B92@TYAPR01MB5692.jpnprd01.prod.outlook.com
When creating and initializing a logical slot, the restart_lsn is set
to the latest WAL insertion point (or the latest replay point on
standbys). Subsequently, WAL records are decoded from that point to
find the start point for extracting changes in the
DecodingContextFindStartpoint() function. Since the initial
restart_lsn could be in the middle of a transaction, the start point
must be a consistent point where we won't see the data for partial
transactions.
Previously, when not building a full snapshot, serialized snapshots
were restored, and the SnapBuild jumps to the consistent state even
while finding the start point. Consequently, the slot's restart_lsn
and confirmed_flush could be set to the middle of a transaction. This
could lead to various unexpected consequences. Specifically, there
were reports of logical decoding decoding partial transactions, and
assertion failures occurred because only subtransactions were decoded
without decoding their top-level transaction until decoding the commit
record.
To resolve this issue, the changes prevent restoring the serialized
snapshot and jumping to the consistent state while finding the start
point.
On v17 and HEAD, a flag indicating whether snapshot restores should be
skipped has been added to the SnapBuild struct, and SNAPBUILD_VERSION
has been bumpded.
On backbranches, the flag is stored in the LogicalDecodingContext
instead, preserving on-disk compatibility.
Backpatch to all supported versions.
Reported-by: Drew Callahan
Reviewed-by: Amit Kapila, Hayato Kuroda
Discussion: https://postgr.es/m/2444AA15-D21B-4CCE-8052-52C7C2DAFE5C%40amazon.com
Backpatch-through: 12
In pgoutput, when converting the child table's tuple format to match the
parent table's, we temporarily create a new slot to store the converted
tuple. However, we missed to drop such temporary slots, leading to
resource leakage.
Reported-by: Bowen Shi
Author: Hou Zhijie
Reviewed-by: Amit Kapila
Backpatch-through: 15
Discussion: https://postgr.es/m/CAM_vCudv8dc3sjWiPkXx5F2b27UV7_YRKRbtSCcE-pv=cVACGA@mail.gmail.com
We missed performing table sync if the invalidation happened while the
non-ready tables list was being prepared. This occurs because the sync
state was set to valid at the end of non-ready table list preparation
irrespective of the invalidations processed while the list is being
prepared.
Fix it by changing the boolean variable to a tri-state enum and by setting
table state to valid only if no invalidations have occurred while the list
is being prepared.
Reprted-by: Alexander Lakhin
Diagnosed-by: Alexander Lakhin
Author: Vignesh C
Reviewed-by: Hou Zhijie, Alexander Lakhin, Ajin Cherian, Amit Kapila
Backpatch-through: 15
Discussion: https://postgr.es/m/711a6afe-edb7-1211-cc27-1bef8239eec7@gmail.com
The invalidation of an active slot is done in two steps:
- Termination of the backend holding it, if any.
- Report that the slot is obsolete, with a conflict cause depending on
the slot's data.
This can be racy because between these two steps the slot mutex would be
released while doing system calls, which means that the effective_xmin
and effective_catalog_xmin could advance during that time, detecting a
conflict cause different than the one originally wanted before the
process owning a slot is terminated.
Holding the mutex longer is not an option, so this commit changes the
code to record the LSNs stored in the slot during the termination of the
process owning the slot.
Bonus thanks to Alexander Lakhin for the various tests and the analysis.
Author: Bertrand Drouvot
Reviewed-by: Michael Paquier, Bharath Rupireddy
Discussion: https://postgr.es/m/ZaTjW2Xh+TQUCOH0@ip-10-97-1-34.eu-west-3.compute.internal
Backpatch-through: 16
This reverts commit 728f86fec65537eade8d9e751961782ddb527934.
The signal handling was a few bricks shy of a load in that commit,
which made the walreceiver non-responsive to SIGTERM while it was
waiting for the connection to be established. That prevented a standby
from being promoted.
Since it was non-essential refactoring, let's revert it to make v16
work the same as earlier releases. I reverted it in 'master' too, to
keep the branches in sync. The refactoring was a good idea as such,
but it needs a bit more work. Once we have developed a complete patch
with this issue fixed, let's re-apply that to 'master'.
Reported-by: Kyotaro Horiguchi
Backpatch-through: 16
Discussion: https://www.postgresql.org/message-id/20231231.200741.1078989336605759878.horikyota.ntt@gmail.com
A superuser may create a subscription with password_required=true, but
which uses a connection string without a password.
Previously, if the owner of such a subscription was changed to a
non-superuser, the non-superuser was able to utilize a password from
another source (like a password file or the PGPASSWORD environment
variable), which should not have been allowed.
This commit adds a step to re-validate the connection string before
connecting.
Reported-by: Jeff Davis
Author: Vignesh C
Reviewed-by: Peter Smith, Robert Haas, Amit Kapila
Discussion: https://www.postgresql.org/message-id/flat/e5892973ae2a80a1a3e0266806640dae3c428100.camel%40j-davis.com
Backpatch-through: 16
The apply worker needs to update the state of the subscription tables to
'READY' during the synchronization phase which requires locking the
corresponding subscription. The apply worker also waits for the
subscription tables to reach the 'SYNCDONE' state after holding the locks
on the subscription and the wait is done using WaitLatch. The 'SYNCDONE'
state is changed by tablesync workers again by locking the corresponding
subscription. Both the state updates use AccessShareLock mode to lock the
subscription, so they can't block each other. However, a backend can
simultaneously try to acquire a lock on the same subscription using
AccessExclusiveLock mode to alter the subscription. Now, the backend's
wait on a lock can sneak in between the apply worker and table sync worker
causing deadlock.
In other words, apply_worker waits for tablesync worker which waits for
backend, and backend waits for apply worker. This is not detected by the
deadlock detector because apply worker uses WaitLatch.
The fix is to release existing locks in apply worker before it starts to
wait for tablesync worker to change the state.
Reported-by: Tomas Vondra
Author: Shlok Kyal
Reviewed-by: Amit Kapila, Peter Smith
Backpatch-through: 12
Discussion: https://postgr.es/m/d291bb50-12c4-e8af-2af2-7bb9bb4d8e3e@enterprisedb.com
Commit 5a991ef8692e accidentally reversed the order of the tuples
and fields parameters, making the error message incorrectly refer
to 3 tuples with 1 field when IDENTIFY_SYSTEM returns 1 tuple and
3 or 4 fields. Fix by changing the order of the parameters. This
also adds a comment describing why we check for < 3 when postgres
since 9.4 has been sending 4 fields.
Backpatch all the way since the bug is almost a decade old.
Author: Tomonari Katsumata <t.katsumata1122@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Bug: #18224
Backpatch-through: v12
52e4f0cd4 introduced a bug in pgoutput in which missing values in tuples
were incorrectly filled in with NULL. The problem was the use of
CreateTupleDescCopy where CreateTupleDescCopyConstr was required, as the
former drops the constraints in the tuple description (specifically, the
default value constraint) on the floor.
The bug could result in incorrectness when a table replicated via
`REPLICA IDENTITY FULL` underwent a schema change that added a column
with a default value. The problem is that in such cases updates fill NULL
values in old tuples for missing columns for default values. Then on the
subscriber, we failed to find a matching tuple and missed updating the
required row.
Author: Nikhil Benesch
Reviewed-by: Hou Zhijie, Amit Kapila
Backpatch-through: 15
Discussion: http://postgr.es/m/CAPWqQZTEpZQamYsGMn6ZDRvVywwpVPiKH6OY4KSgA+NmeqFNzA@mail.gmail.com
The copy command formed for initial sync was using parenthesis for tables
with no columns leading to syntax error. This patch avoids adding
parenthesis for such tables.
Reported-by: Justin G
Author: Vignesh C
Reviewed-by: Peter Smith, Amit Kapila
Backpatch-through: 15
Discussion: http://postgr.es/m/18203-df37fe354b626670@postgresql.org
The pgoutput module uses a global variable (publish_no_origin) to cache
the action for the origin filter, but we didn't reset the flag when
shutting down the output plugin, so subsequent retries may access the
previous publish_no_origin value.
We fix this by storing the flag in the output plugin's private data.
Additionally, the patch removes the currently unused origin string from the
structure.
For the back branch, to avoid changing the exposed structure, we eliminated the
global variable and instead directly used the origin string for change
filtering.
Author: Hou Zhijie
Reviewed-by: Amit Kapila, Michael Paquier
Backpatch-through: 16
Discussion: http://postgr.es/m/OS0PR01MB571690EF24F51F51EFFCBB0E94FAA@OS0PR01MB5716.jpnprd01.prod.outlook.com
The logical_replication_mode GUC is intended for testing and debugging
purposes, but its current name may be misleading and encourage users to make
unnecessary changes.
To avoid confusion, renaming the GUC to a less misleading name
debug_logical_replication_streaming that casual users are less likely to mistakenly
assume needs to be modified in a regular logical replication setup.
Author: Hou Zhijie <houzj.fnst@cn.fujitsu.com>
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/d672d774-c44b-6fec-f993-793e744f169a%40eisentraut.org
The SnapBuildRestoreContents() used a const value in the error message to
indicate the size in bytes it was expecting to read from the serialized
snapshot file. Fix it by reporting the size that was actually passed.
Author: Hou Zhijie
Reviewed-by: Amit Kapila
Backpatch-through: 16
Discussion: http://postgr.es/m/OS0PR01MB5716D408364F7DF32221C08D941FA@OS0PR01MB5716.jpnprd01.prod.outlook.com
Previously, when selecting an usable index for update/delete for the
REPLICA IDENTITY FULL table, in IsIndexOnlyExpression(), we used to
check if all index fields are not expressions. However, it was not
necessary, because it is enough to check if only the leftmost index
field is not an expression (and references the remote table column)
and this check has already been done by
RemoteRelContainsLeftMostColumnOnIdx().
This commit removes IsIndexOnlyExpression() and
RemoteRelContainsLeftMostColumnOnIdx() and all checks for usable
indexes for REPLICA IDENTITY FULL tables are now performed by
IsIndexUsableForReplicaIdentityFull().
Backpatch this to remain the code consistent.
Reported-by: Peter Smith
Reviewed-by: Amit Kapila, Önder Kalacı
Discussion: https://postgr.es/m/CAHut%2BPsGRE5WSsY0jcLHJEoA17MrbP9yy8FxdjC_ZOAACxbt%2BQ%40mail.gmail.com
Backpatch-through: 16
We include the message type while displaying an error context in the
apply worker. Now, while retrieving the message type string if the
message type is unknown we throw an error that will hide the original
error. So, instead, we need to simply return the string indicating an
unknown message type.
Reported-by: Ashutosh Bapat
Author: Euler Taveira, Amit Kapila
Reviewed-by: Ashutosh Bapat
Backpatch-through: 15
Discussion: https://postgr.es/m/CAExHW5suAEDW-mBZt_qu4RVxWZ1vL54-L+ci2zreYWebpzxYsA@mail.gmail.com
Commit 89e46da5e allowed REPLICA IDENTITY FULL tables to use an index
on the subscriber during apply of update/delete. This commit clarifies
in the documentation that the leftmost field of candidate indexes must
be a column (not an expression) that references the published relation
column.
The source code comments are also updated accordingly.
Reviewed-by: Peter Smith, Amit Kapila
Discussion: https://postgr.es/m/CAD21AoDJjffEvUFKXT27Q5U8-UU9JHv4rrJ9Ke8Zkc5UPWHLvA@mail.gmail.com
Backpatch-through: 16
Clear any potential stale next_phase_at value from the snapshot
builder which otherwise may trip an assertion check ensuring
that there is no next_phase_at value.
This can be reproduced by running 80 concurrent sessions like
the below where $c is a loop counter (assumes there has been
1..$c databases created) :
echo "
CREATE TABLE replication_example(id SERIAL PRIMARY KEY,
somedata int,
text varchar(120));
SELECT 'init' FROM
pg_create_logical_replication_slot('regression_slot_$c',
'test_decoding');
SELECT data FROM
pg_logical_slot_get_changes('regression_slot_$c', NULL,
NULL, 'include-xids', '0',
'skip-empty-xacts', '1');
" | psql -d regress_$c >>psql.log &
Backpatch down to v16.
Bug: #17695
Author: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Alexander Lakhin <exclusion@gmail.com>
Reported-by: bowenshi <zxwsbg@qq.com>
Discussion: https://postgr.es/m/17695-6be9277c9295985f@postgresql.org
Backpatch-through: v16
Run pgindent and pgperltidy. It seems we're still some ways
away from all committers doing this automatically. Now that
we have a buildfarm animal that will whine about poorly-indented
code, we'll try to keep the tree more tidy.
Discussion: https://postgr.es/m/3156045.1687208823@sss.pgh.pa.us
Commit c3afe8cf5a added a new password_required option but forgot that you
need database access to check whether an arbitrary role ID is a superuser.
Commit e7e7da2f8d fixed a similar bug in apply worker, and this patch
fixes a similar bug in tablesync worker.
Author: Hou Zhijie
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/OS0PR01MB571607F5A9D723755268D36294759@OS0PR01MB5716.jpnprd01.prod.outlook.com
Commit 482675987 introduced "run_as_owner" subscription option so that
subscription runs with either the permissions of the subscription
owner or the permission of the table owner. However, tablesync workers
did not use this option for the initial data copy.
With this change, tablesync workers run with appropriate permissions
based on "run_as_owner" option.
Ajin Cherian, with changes and regression tests added by me.
Reported-By: Amit Kapila
Author: Ajin Cherian, Masahiko Sawada
Reviewed-by: Ajin Cherian, Amit Kapila
Discussion: https://postgr.es/m/CAA4eK1L=qzRHPEn+qeMoKQGFBzqGoLBzt_ov0A89iFFiut+ppA@mail.gmail.com
The apply worker was not reloading the configuration while processing
messages if there is a continuous flow of messages from upstream. It was
also not reloading the configuration if there is a change in the
configuration after it has waited for the message and before receiving the
new replication message. This can lead to failure in tests because we
expect that after reload, the behavior of apply worker to respect the
changed GUCs.
We found this while analyzing a rare buildfarm failure.
Author: Hou Zhijie
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/OS0PR01MB5716AF9079CC0755CD015322947E9@OS0PR01MB5716.jpnprd01.prod.outlook.com
WalSndWakeup() currently loops through all the walsenders slots, with a
spinlock acquisition and release for every iteration, to wake up waiting
walsenders.
This commonly was not a problem before e101dfac3a53c. But, to allow logical
decoding on standbys, we need to wake up logical walsenders after every WAL
record is applied on the standby, rather just when flushing WAL or switching
timelines. This causes a performance regression for workloads replaying a lot
of WAL records.
To solve this, we use condition variable (CV) to efficiently wake up
walsenders in WalSndWakeup().
Every walsender prepares to sleep on a shared memory CV. Note that it just
prepares to sleep on the CV (i.e., adds itself to the CV's waitlist), but does
not actually wait on the CV (IOW, it never calls ConditionVariableSleep()). It
still uses WaitEventSetWait() for waiting, because CV infrastructure doesn't
handle FeBe socket events currently. The processes (startup process,
walreceiver etc.) wanting to wake up walsenders use
ConditionVariableBroadcast(), which in turn calls SetLatch(), helping
walsenders come out of WaitEventSetWait().
We use separate shared memory CVs for physical and logical walsenders for
selective wake ups, see WalSndWakeup() for more details.
This approach is simple and reasonably efficient. But not very elegant. But
for 16 it seems to be a better path than a larger redesign of the CV
mechanism. A desirable future improvement would be to add support for CVs
into WaitEventSetWait().
This still leaves us with a small regression in very extreme workloads (due to
the spinlock acquisition in ConditionVariableBroadcast() when there are no
waiters) - but that seems acceptable.
Reported-by: Andres Freund <andres@anarazel.de>
Suggested-by: Andres Freund <andres@anarazel.de>
Author: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Reviewed-by: Zhijie Hou <houzj.fnst@fujitsu.com>
Discussion: https://www.postgresql.org/message-id/20230509190247.3rrplhdgem6su6cg%40awork3.anarazel.de
Run pgindent, pgperltidy, and reformat-dat-files.
This set of diffs is a bit larger than typical. We've updated to
pg_bsd_indent 2.1.2, which properly indents variable declarations that
have multi-line initialization expressions (the continuation lines are
now indented one tab stop). We've also updated to perltidy version
20230309 and changed some of its settings, which reduces its desire to
add whitespace to lines to make assignments etc. line up. Going
forward, that should make for fewer random-seeming changes to existing
code.
Discussion: https://postgr.es/m/20230428092545.qfb3y5wcu4cm75ur@alvherre.pgsql
The idea of EvalPlanQual is that we replace the query's scan of the
result relation with a single injected tuple, and see if we get a
tuple out, thereby implying that the injected tuple still passes the
query quals. (In join cases, other relations in the query are still
scanned normally.) This logic was not updated when commit 86dc90056
made it possible for a single DML query plan to have multiple result
relations, when the query target relation has inheritance or partition
children. We replaced the output for the current result relation
successfully, but other result relations were still scanned normally;
thus, if any other result relation contained a tuple satisfying the
quals, we'd think the EPQ check passed, even if it did not pass for
the injected tuple itself. This would lead to update or delete
actions getting performed when they should have been skipped due to
a conflicting concurrent update in READ COMMITTED isolation mode.
Fix by blocking all sibling result relations from emitting tuples
during an EvalPlanQual recheck. In the back branches, the fix is
complicated a bit by the need to not change the size of struct
EPQState (else we'd have ABI-breaking changes in offsets in
struct ModifyTableState). Like the back-patches of 3f7836ff6
and 4b3e37993, add a separately palloc'd struct to avoid that.
The logic is the same as in HEAD otherwise.
This is only a live bug back to v14 where 86dc90056 came in.
However, I chose to back-patch the test cases further, on the
grounds that this whole area is none too well tested. I skipped
doing so in v11 though because none of the test applied cleanly,
and it didn't quite seem worth extra work for a branch with only
six months to live.
Per report from Ante Krešić (via Aleksander Alekseev)
Discussion: https://postgr.es/m/CAJ7c6TMBTN3rcz4=AjYhLPD_w3FFT0Wq_C15jxCDn8U4tZnH1g@mail.gmail.com
The callback function pa_shutdown() accesses MyLogicalRepWorker which may
not be initialized if there is an error during the initialization of the
parallel apply worker. The other problem is that by the time it is invoked
even after the initialization of the worker, the MyLogicalRepWorker will
be reset by another callback logicalrep_worker_onexit. So, it won't have
the required information.
To fix this, register the shutdown callback after we are attached to the
worker slot.
After this fix, we observed another issue which is that sometimes the
leader apply worker tries to receive the message from the error queue that
might already be detached by the parallel apply worker leading to an
error. To prevent such an error, we ensure that the leader apply worker
detaches from the parallel apply worker's error queue before stopping it.
Reported-by: Sawada Masahiko
Author: Hou Zhijie
Reviewed-by: Sawada Masahiko, Amit Kapila
Discussion: https://postgr.es/m/CAD21AoDo+yUwNq6nTrvE2h9bB2vZfcag=jxWc7QxuWCmkDAqcA@mail.gmail.com
During exit, the logical replication apply worker tries to release session
level locks, if any. However, if the apply worker exits due to an error
before its connection is initialized, trying to release locks can lead to
assertion failure. The locks will be acquired once the worker is
initialized, so we don't need to release them till the worker
initialization is complete.
Reported-by: Alexander Lakhin
Author: Hou Zhijie based on inputs from Sawada Masahiko and Amit Kapila
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/2185d65f-5aae-3efa-c48f-fb42b173ef5c@gmail.com
Unsurprisingly, this requires wal_level = logical to be set on the primary and
standby. The infrastructure added in 26669757b6a ensures that slots are
invalidated if the primary's wal_level is lowered.
Creating a slot on a standby waits for a xl_running_xact record to be
processed. If the primary is idle (and thus not emitting xl_running_xact
records), that can take a while. To make that faster, this commit also
introduces the pg_log_standby_snapshot() function. By executing it on the
primary, completion of slot creation on the standby can be accelerated.
Note that logical decoding on a standby does not itself enforce that required
catalog rows are not removed. The user has to use physical replication slots +
hot_standby_feedback or other measures to prevent that. If catalog rows
required for a slot are removed, the slot is invalidated.
See 6af1793954e for an overall design of logical decoding on a standby.
Bumps catversion, for the addition of the pg_log_standby_snapshot() function.
Author: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Author: Andres Freund <andres@anarazel.de> (in an older version)
Author: Amit Khandekar <amitdkhan.pg@gmail.com> (in an older version)
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: FabrÌzio de Royes Mello <fabriziomello@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Physical walsenders can't send data until it's been flushed; logical
walsenders can't decode and send data until it's been applied. On the
standby, the WAL is flushed first, which will only wake up physical
walsenders; and then applied, which will only wake up logical
walsenders.
Previously, all walsenders were awakened when the WAL was flushed. That
was fine for logical walsenders on the primary; but on the standby the
flushed WAL would have been not applied yet, so logical walsenders were
awakened too early.
Per idea from Jeff Davis and Amit Kapila.
Author: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Reviewed-By: Jeff Davis <pgsql@j-davis.com>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/CAA4eK1+zO5LUeisabX10c81LU-fWMKO4M9Wyg1cdkbW7Hqh6vQ@mail.gmail.com
During WAL replay on the standby, when a conflict with a logical slot is
identified, invalidate such slots. There are two sources of conflicts:
1) Using the information added in 6af1793954e, logical slots are invalidated if
required rows are removed
2) wal_level on the primary server is reduced to below logical
Uses the infrastructure introduced in the prior commit. FIXME: add commit
reference.
Change InvalidatePossiblyObsoleteSlot() to use a recovery conflict to
interrupt use of a slot, if called in the startup process. The new recovery
conflict is added to pg_stat_database_conflicts, as confl_active_logicalslot.
See 6af1793954e for an overall design of logical decoding on a standby.
Bumps catversion for the addition of the pg_stat_database_conflicts column.
Bumps PGSTAT_FILE_FORMAT_ID for the same reason.
Author: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Author: Andres Freund <andres@anarazel.de>
Author: Amit Khandekar <amitdkhan.pg@gmail.com> (in an older version)
Reviewed-by: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com>
Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/20230407075009.igg7be27ha2htkbt@awork3.anarazel.de
Previously we had checks for this in multiple places. Support for logical
decoding on standbys will add other forms of invalidation, making it worth
while to centralize the checks.
This slightly changes the error message for both the walsender and SQL
interface. Particularly the SQL interface error was inaccurate, as the "This
slot has never previously reserved WAL" portion was unreachable.
Reviewed-by: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
Discussion: https://postgr.es/m/20230407075009.igg7be27ha2htkbt@awork3.anarazel.de
This is mainly useful because the upcoming logical-decoding-on-standby feature
adds further reasons for invalidating slots, and we don't want to end up with
multiple invalidated_* fields, or check different attributes.
Eventually we should consider not resetting restart_lsn when invalidating a
slot due to max_slot_wal_keep_size. But that's a user visible change, so left
for later.
Increases SLOT_VERSION, due to the changed field (with a different alignment,
no less).
Reviewed-by: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
Discussion: https://postgr.es/m/20230407075009.igg7be27ha2htkbt@awork3.anarazel.de
This option is normally false, but can be set to true to obtain
the legacy behavior where the subscription runs with the permissions
of the subscription owner rather than the permissions of the
table owner. The advantages of this mode are (1) it doesn't require
that the subscription owner have permission to SET ROLE to each
table owner and (2) since no role switching occurs, the
SECURITY_RESTRICTED_OPERATION restrictions do not apply.
On the downside, it allows any table owner to easily usurp
the privileges of the subscription owner - basically, to take
over their account. Because that's generally quite undesirable,
we don't make this mode the default, but we do make it available,
just in case the new behavior causes too many problems for someone.
Discussion: http://postgr.es/m/CA+TgmoZ-WEeG6Z14AfH7KhmpX2eFh+tZ0z+vf0=eMDdbda269g@mail.gmail.com
