Previously, transaction aborts were detected concurrently only during
system catalog scans while replaying a transaction in streaming mode.
This commit adds an additional CLOG lookup to check the transaction
status, allowing the logical decoding to skip changes also when it
doesn't touch system catalogs, if the transaction is already
aborted. This optimization enhances logical decoding performance,
especially for large transactions that have already been rolled back,
as it avoids unnecessary disk or network I/O.
To avoid potential slowdowns caused by frequent CLOG lookups for small
transactions (most of which commit), the CLOG lookup is performed only
for large transactions before eviction. The performance benchmark
results showed there is not noticeable performance regression due to
CLOG lookups.
Reviewed-by: Amit Kapila, Peter Smith, Vignesh C, Ajin Cherian
Reviewed-by: Dilip Kumar, Andres Freund
Discussion: https://postgr.es/m/CAD21AoDht9Pz_DFv_R2LqBTBbO4eGrpa9Vojmt5z5sEx3XwD7A@mail.gmail.com
The test was unstable in branches 14 and 15 as we were relying on the
number of changes in the table having a toast column to start streaming.
On branches >= 16, we have a GUC debug_logical_replication_streaming which
can stream each change, so the test was stable in those branches.
Change the test to use PREPARE TRANSACTION as that should make the result
consistent and test the code changed in 022564f60c.
Reported-by: Daniel Gustafsson as per buildfarm
Author: Hou Zhijie, Amit Kapila
Backpatch-through: 14
Discussion: https://postgr.es/m/8C2F86AA-981E-4803-B14D-E264C0255330@yesql.se
During logical decoding of in-progress transactions, we perform the toast
table scan while fetching the default toast value for an attribute. We
forgot to initialize the flag during this scan to indicate that the system
table scan is in progress. We need this flag to ensure that during logical
decoding we never directly access the tableam or heap APIs because we check
for concurrent aborts only in systable_* APIs.
Reported-by: Alexander Lakhin
Author: Takeshi Ideriha, Hou Zhijie
Reviewed-by: Amit Kapila, Hou Zhijie
Backpatch-through: 14
Discussion: https://postgr.es/m/18641-6687273b7f15269d@postgresql.org
Commit 5bec1d6bc5 changed the memory usage updates of the
ReorderBufferTXN to zero all at once by subtracting txn->size, rather
than updating it for each change. However, if TOAST reconstruction
data remained in the transaction when freeing it, there were cases
where it further subtracted the memory counter from zero, resulting in
an assertion failure.
This change calculates the memory size for each change and updates the
memory usage to precisely the amount that has been freed.
Backpatch to v17, where this was introducd.
Reviewed-by: Amit Kapila, Shlok Kyal
Discussion: https://postgr.es/m/CAD21AoAqkNUvicgKPT_dXzNoOwpPkVTg0QPPxEcWmzT0moCJ1g%40mail.gmail.com
Backpatch-through: 17
ReorderBufferImmediateInvalidation() executes invalidation messages in
an aborted transaction. However, RelationFlushRelation sometimes
required a valid resource owner, to temporarily increment the refcount
of the relache entry. Commit b8bff07daa worked around that in the main
subtransaction abort function, AbortSubTransaction(), but missed this
similar case in ReorderBufferImmediateInvalidation().
To fix, introduce a separate function to invalidate a relcache
entry. It does the same thing as RelationClearRelation(rebuild==true)
does when outside a transaction, but can be called without
incrementing the refcount.
Add regression test. Before this fix, it failed with:
ERROR: ResourceOwnerEnlarge called after release started
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://www.postgresql.org/message-id/e56be7d9-14b1-664d-0bfc-00ce9772721c@gmail.com
This commit introduces a new SQL function pg_sync_replication_slots()
which is used to synchronize the logical replication slots from the
primary server to the physical standby so that logical replication can be
resumed after a failover or planned switchover.
A new 'synced' flag is introduced in pg_replication_slots view, indicating
whether the slot has been synchronized from the primary server. On a
standby, synced slots cannot be dropped or consumed, and any attempt to
perform logical decoding on them will result in an error.
The logical replication slots on the primary can be synchronized to the
hot standby by using the 'failover' parameter of
pg-create-logical-replication-slot(), or by using the 'failover' option of
CREATE SUBSCRIPTION during slot creation, and then calling
pg_sync_replication_slots() on standby. For the synchronization to work,
it is mandatory to have a physical replication slot between the primary
and the standby aka 'primary_slot_name' should be configured on the
standby, and 'hot_standby_feedback' must be enabled on the standby. It is
also necessary to specify a valid 'dbname' in the 'primary_conninfo'.
If a logical slot is invalidated on the primary, then that slot on the
standby is also invalidated.
If a logical slot on the primary is valid but is invalidated on the
standby, then that slot is dropped but will be recreated on the standby in
the next pg_sync_replication_slots() call provided the slot still exists
on the primary server. It is okay to recreate such slots as long as these
are not consumable on standby (which is the case currently). This
situation may occur due to the following reasons:
- The 'max_slot_wal_keep_size' on the standby is insufficient to retain
WAL records from the restart_lsn of the slot.
- 'primary_slot_name' is temporarily reset to null and the physical slot
is removed.
The slot synchronization status on the standby can be monitored using the
'synced' column of pg_replication_slots view.
A functionality to automatically synchronize slots by a background worker
and allow logical walsenders to wait for the physical will be done in
subsequent commits.
Author: Hou Zhijie, Shveta Malik, Ajin Cherian based on an earlier version by Peter Eisentraut
Reviewed-by: Masahiko Sawada, Bertrand Drouvot, Peter Smith, Dilip Kumar, Nisha Moond, Kuroda Hayato, Amit Kapila
Discussion: https://postgr.es/m/514f6f2f-6833-4539-39f1-96cd1e011f23@enterprisedb.com
This commit adds the failover property to the replication slot. The
failover property indicates whether the slot will be synced to the standby
servers, enabling the resumption of corresponding logical replication
after failover. But note that this commit does not yet include the
capability to sync the replication slot; the subsequent commits will add
that capability.
A new optional parameter 'failover' is added to the
pg_create_logical_replication_slot() function. We will also enable to set
'failover' option for slots via the subscription commands in the
subsequent commits.
The value of the 'failover' flag is displayed as part of
pg_replication_slots view.
Author: Hou Zhijie, Shveta Malik, Ajin Cherian
Reviewed-by: Peter Smith, Bertrand Drouvot, Dilip Kumar, Masahiko Sawada, Nisha Moond, Kuroda, Hayato, Amit Kapila
Discussion: https://postgr.es/m/514f6f2f-6833-4539-39f1-96cd1e011f23@enterprisedb.com
Since its introduction, LogLogicalMessage() (via the SQL interface
pg_logical_emit_message()) has never included a call to XLogFlush(),
causing it to potentially lose messages on a crash when used in
non-transactional mode. This has come up to me as a problem while
playing with ideas to design a test suite for what has become
039_end_of_wal.pl introduced in bae868caf2 by Thomas Munro, because
there are no direct ways to force a WAL flush via SQL.
The default is false, to not flush messages and influence existing
use-cases where this function could be used. If set to true, the
message emitted is flushed before returning back to the caller, making
the message durable on crash. This new option has no effect when using
pg_logical_emit_message() in transactional mode, as the record's flush
is guaranteed by the WAL record generated by the transaction committed.
Two queries of test_decoding are tweaked to cover the new code path for
the flush.
Bump catalog version.
Author: Michael Paquier
Reviewed-by: Andres Freund, Amit Kapila, Fujii Masao, Tung Nguyen, Tomas
Vondra
Discussion: https://postgr.es/m/ZNsdThSe2qgsfs7R@paquier.xyz
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
Some of the test_decoding test output was extremely wide, because it
deals with massive toasted values, and the aligned mode causes psql to
produce 200kB of whitespace and dashes. Change to unaligned mode
temporarily to avoid that behavior.
Backpatch to 14, where it applies cleanly.
Discussion: https://postgr.es/m/20230405103953.sxleixp3uz5lazst@alvherre.pgsql
In test_decoding module, when skip_empty_xacts option was specified, add
BEGIN/COMMIT for transactional messages. This makes the handling of
transactional messages consistent irrespective of whether skip_empty_xacts
option was specified.
We decided not to backpatch this change because skip_empty_xacts is
primarily used to have consistent test results across different runs and
this change won't help with that.
Author: Vignesh C
Reviewed-by: Ashutosh Bapat, Hou Zhijie
Discussion: https://postgr.es/m/CAExHW5ujRhbOz6_aTq_jQA8NjeFqq9d_8G9viShWvXx8gdSXiQ@mail.gmail.com
This patch adds a new SUBSCRIPTION parameter "origin". It specifies
whether the subscription will request the publisher to only send changes
that don't have an origin or send changes regardless of origin. Setting it
to "none" means that the subscription will request the publisher to only
send changes that have no origin associated. Setting it to "any" means
that the publisher sends changes regardless of their origin. The default
is "any".
Usage:
CREATE SUBSCRIPTION sub1 CONNECTION 'dbname=postgres port=9999'
PUBLICATION pub1 WITH (origin = none);
This can be used to avoid loops (infinite replication of the same data)
among replication nodes.
This feature allows filtering only the replication data originating from
WAL but for initial sync (initial copy of table data) we don't have such a
facility as we can only distinguish the data based on origin from WAL. As
a follow-up patch, we are planning to forbid the initial sync if the
origin is specified as none and we notice that the publication tables were
also replicated from other publishers to avoid duplicate data or loops.
We forbid to allow creating origin with names 'none' and 'any' to avoid
confusion with the same name options.
Author: Vignesh C, Amit Kapila
Reviewed-By: Peter Smith, Amit Kapila, Dilip Kumar, Shi yu, Ashutosh Bapat, Hayato Kuroda
Discussion: https://postgr.es/m/CALDaNm0gwjY_4HFxvvty01BOT01q_fJLKQ3pWP9=9orqubhjcQ@mail.gmail.com
- subscriber stats reset path was untested
- slot stat sreset path for all slots was untested
- pg_stat_database.sessions etc was untested
- pg_stat_reset_shared() was untested, for any kind of shared stats
- pg_stat_reset() was untested
Author: Melanie Plageman <melanieplageman@gmail.com>
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20220303021600.hs34ghqcw6zcokdh@alap3.anarazel.de
In the stats collector days it was hard to write tests for the stats system,
because fundamentally delivery of stats messages over UDP was not
synchronous (nor guaranteed). Now we easily can force pending stats updates to
be flushed synchronously.
This moves stats.sql into a parallel group, there isn't a reason for it to run
in isolation anymore. And it may shake out some bugs.
Bumps catversion.
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20220303021600.hs34ghqcw6zcokdh@alap3.anarazel.de
MERGE performs actions that modify rows in the target table using a
source table or query. MERGE provides a single SQL statement that can
conditionally INSERT/UPDATE/DELETE rows -- a task that would otherwise
require multiple PL statements. For example,
MERGE INTO target AS t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED AND t.balance > s.delta THEN
UPDATE SET balance = t.balance - s.delta
WHEN MATCHED THEN
DELETE
WHEN NOT MATCHED AND s.delta > 0 THEN
INSERT VALUES (s.sid, s.delta)
WHEN NOT MATCHED THEN
DO NOTHING;
MERGE works with regular tables, partitioned tables and inheritance
hierarchies, including column and row security enforcement, as well as
support for row and statement triggers and transition tables therein.
MERGE is optimized for OLTP and is parameterizable, though also useful
for large scale ETL/ELT. MERGE is not intended to be used in preference
to existing single SQL commands for INSERT, UPDATE or DELETE since there
is some overhead. MERGE can be used from PL/pgSQL.
MERGE does not support targetting updatable views or foreign tables, and
RETURNING clauses are not allowed either. These limitations are likely
fixable with sufficient effort. Rewrite rules are also not supported,
but it's not clear that we'd want to support them.
Author: Pavan Deolasee <pavan.deolasee@gmail.com>
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Author: Amit Langote <amitlangote09@gmail.com>
Author: Simon Riggs <simon.riggs@enterprisedb.com>
Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Reviewed-by: Andres Freund <andres@anarazel.de> (earlier versions)
Reviewed-by: Peter Geoghegan <pg@bowt.ie> (earlier versions)
Reviewed-by: Robert Haas <robertmhaas@gmail.com> (earlier versions)
Reviewed-by: Japin Li <japinli@hotmail.com>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com>
Reviewed-by: Zhihong Yu <zyu@yugabyte.com>
Discussion: https://postgr.es/m/CANP8+jKitBSrB7oTgT9CY2i1ObfOt36z0XMraQc+Xrz8QB0nXA@mail.gmail.com
Discussion: https://postgr.es/m/CAH2-WzkJdBuxj9PO=2QaO9-3h3xGbQPZ34kJH=HukRekwM-GZg@mail.gmail.com
Discussion: https://postgr.es/m/20201231134736.GA25392@alvherre.pgsql
Some of the test_decoding regression tests are unstable due to modifying
a sequence. The first increment of a sequence after a checkpoint is
always logged (and thus decoded), which makes the output unpredictable.
The runs are usually much shorter than a checkpoint internal, so these
failures are rare, but we've seen a couple of them on animals that are
either slow or are running with valgrind/clobber cache/...
Fixed by skipping sequence decoding in most tests, with the exception of
the test aimed at testing decoding of sequences.
Reported-by: Amita Kapila
Discussion: https://postgr.es/m/d045f3c2-6cfb-06d3-5540-e63c320df8bc@enterprisedb.com
Regression tests need to use skip-empty-xacts = false, because there
might be accidental concurrent activity (like autovacuum), particularly
on slow machines. The tests added by 80901b3291 failed to do that in a
couple places, triggering occasional failures on buildfarm.
Fixing the tests however uncovered a bug in the code, because sequence
callbacks did not handle skip-empty-xacts properly. For trasactional
increments we need to check/update the xact_wrote_changes flag, and emit
the BEGIN if it's the first change in the transaction.
Reported-by: Andres Freund
Discussion: https://postgr.es/m/20220212220413.b25amklo7t4xb7ni%40alap3.anarazel.de
Commit 0da92dc530 improved the logical decoding infrastructure to handle
sequences, and did various changes to related parts (WAL logging etc.).
But it did not include any implementation of the new callbacks added to
OutputPluginCallbacks.
This extends test_decoding with two callbacks to decode sequences. The
decoding of sequences may be disabled using 'include-sequences', a new
option of the output plugin.
Author: Tomas Vondra, Cary Huang
Reviewed-by: Peter Eisentraut, Hannu Krosing, Andres Freund
Discussion: https://postgr.es/m/d045f3c2-6cfb-06d3-5540-e63c320df8bc@enterprisedb.com
Discussion: https://postgr.es/m/1710ed7e13b.cd7177461430746.3372264562543607781@highgo.ca
When using replication origins, pg_replication_origin_xact_setup() is an
optional choice to be able to set a LSN and a timestamp to mark the
origin, which would be additionally added to WAL for transaction commits
or aborts (including 2PC transactions). An assertion in the code path
of PREPARE TRANSACTION assumed that this data should always be set, so
it would trigger when using replication origins without setting up an
origin LSN. Some tests are added to cover more this kind of scenario.
Oversight in commit 1eb6d65.
Per discussion with Amit Kapila and Masahiko Sawada.
Discussion: https://postgr.es/m/YbbBfNSvMm5nIINV@paquier.xyz
Backpatch-through: 11
This commit adds a set of functions able to look at the contents of
various paths related to replication slots:
- pg_ls_logicalsnapdir, for pg_logical/snapshots/
- pg_ls_logicalmapdir, for pg_logical/mappings/
- pg_ls_replslotdir, for pg_replslot/<slot_name>/
These are intended to be used by monitoring tools. Unlike pg_ls_dir(),
execution permission can be granted to non-superusers. Roles members of
pg_monitor gain have access to those functions.
Bump catalog version.
Author: Bharath Rupireddy
Reviewed-by: Nathan Bossart, Justin Pryzby
Discussion: https://postgr.es/m/CALj2ACWsfizZjMN6bzzdxOk1ADQQeSw8HhEjhmVXn_Pu+7VzLw@mail.gmail.com
Commit 325f2ec555 introduced pg_class.relwrite to skip operations on
tables created as part of a heap rewrite during DDL. It links such
transient heaps to the original relation OID via this new field in
pg_class but forgot to do anything about toast tables. So, logical
decoding was not able to skip operations on internally created toast
tables. This leads to an error when we tried to decode the WAL for the
next operation for which it appeared that there is a toast data where
actually it didn't have any toast data.
To fix this, we set pg_class.relwrite for internally created toast tables
as well which allowed skipping operations on them during logical decoding.
Author: Bertrand Drouvot
Reviewed-by: David Zhang, Amit Kapila
Backpatch-through: 11, where it was introduced
Discussion: https://postgr.es/m/b5146fb1-ad9e-7d6e-f980-98ed68744a7c@amazon.com
While decoding the multi-insert WAL we can't clean the toast untill we get
the last insert of that WAL record. Now if we stream the changes before we
get the last change, the memory for toast chunks won't be released and we
expect the txn to have streamed all changes after streaming. This
restriction is mainly to ensure the correctness of streamed transactions
and it doesn't seem worth uplifting such a restriction just to allow this
case because anyway we will stream the transaction once such an insert is
complete.
Previously we were using two different flags (one for toast tuples and
another for speculative inserts) to indicate partial changes. Now instead
we replaced both of them with a single flag to indicate partial changes.
Reported-by: Pavan Deolasee
Author: Dilip Kumar
Reviewed-by: Pavan Deolasee, Amit Kapila
Discussion: https://postgr.es/m/CABOikdN-_858zojYN-2tNcHiVTw-nhxPwoQS4quExeweQfG1Ug@mail.gmail.com
Some of the tests were not considering that the slot's spill stats could be
received by the stats collector after we have reset the stats. Remove
those tests and don't check total bytes decoded and sent to output plugin
in the spilled stats test as we can send the spilled stats to the stats
collector before actually sending the changes to output plugin.
Reported-by: Tom Lane as per buildfarm
Author: Vignesh C, Sawada Masahiko
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
As per analysis, it appears that the 'drop slot' message from the previous
test and 'create slot' message of the new test are either missed or not
yet delivered to the stats collector due to which we will still see the
stats from the old slot. This can happen rarely which could be the reason
that we are seeing some failures in the buildfarm randomly. To avoid that
we are using a different slot name for the tests in
test_decoding/sql/stats.sql.
Reported-by: Tom Lane based on buildfarm reports
Author: Sawada Masahiko
Reviewed-by: Amit Kapila, Vignesh C
Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
In the new test after resetting the stats, we were not waiting for the
stats message to be delivered. Also, we need to decode the results for
the new test, otherwise, it will show the old stats.
In passing,
a. Change docs added by commit f5fc2f5b23 as per suggestion by
Justin Pryzby.
b. Bump the PGSTAT_FILE_FORMAT_ID as commit f5fc2f5b23 changes the file
format of stats.
Reported-by: Tom Lane based on buildfarm reports
Author: Vignesh C, Justin Pryzby
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
This adds the statistics about total transactions count and total
transaction data logically sent to the decoding output plugin from
ReorderBuffer. Users can query the pg_stat_replication_slots view to check
these stats.
Suggested-by: Andres Freund
Author: Vignesh C and Amit Kapila
Reviewed-by: Sawada Masahiko, Amit Kapila
Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
When accessing replication slot stats, introduced in 9868167500,
pgstat_read_statsfiles() reads the data into newly allocated
memory. Unfortunately the current memory context at that point is the
callers, leading to leaks and use-after-free dangers.
The fix is trivial, explicitly use pgStatLocalContext. There's some
potential for further improvements, but that's outside of the scope of
this bugfix.
No backpatch necessary, feature is only in HEAD.
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210317230447.c7uc4g3vbs4wi32i@alap3.anarazel.de
Commit 0aa8a01d04 extends the output plugin API to allow decoding of
prepared xacts and allowed the user to enable/disable the two-phase option
via pg_logical_slot_get_changes(). This can lead to a problem such that
the first time when it gets changes via pg_logical_slot_get_changes()
without two_phase option enabled it will not get the prepared even though
prepare is after consistent snapshot. Now next time during getting changes,
if the two_phase option is enabled it can skip prepare because by that
time start decoding point has been moved. So the user will only get commit
prepared.
Allow to enable/disable this option at the create slot time and default
will be false. It will break the existing slots which is fine in a major
release.
Author: Ajin Cherian
Reviewed-by: Amit Kapila and Vignesh C
Discussion: https://postgr.es/m/d0f60d60-133d-bf8d-bd70-47784d8fabf3@enterprisedb.com
This patch allows PREPARE-time decoding of two-phase transactions (if the
output plugin supports this capability), in which case the transactions
are replayed at PREPARE and then committed later when COMMIT PREPARED
arrives.
Now that we decode the changes before the commit, the concurrent aborts
may cause failures when the output plugin consults catalogs (both system
and user-defined).
We detect such failures with a special sqlerrcode
ERRCODE_TRANSACTION_ROLLBACK introduced by commit 7259736a6e and stop
decoding the remaining changes. Then we rollback the changes when rollback
prepared is encountered.
Author: Ajin Cherian and Amit Kapila based on previous work by Nikhil Sontakke and Stas Kelvich
Reviewed-by: Amit Kapila, Peter Smith, Sawada Masahiko, Arseny Sher, and Dilip Kumar
Tested-by: Takamichi Osumi
Discussion:
https://postgr.es/m/02DA5F5E-CECE-4D9C-8B4B-418077E2C010@postgrespro.ruhttps://postgr.es/m/CAMGcDxeqEpWj3fTXwqhSwBdXd2RS9jzwWscO-XbeCfso6ts3+Q@mail.gmail.com
Change the attribute 'name' to 'slot_name' in pg_stat_replication_slots
view to make it clear and that way we will be consistent with the other
places like pg_stat_wal_receiver view where we display the same attribute.
In the passing, fix the typo in one of the macros in the related code.
Bump the catversion as we have modified the name in the catalog as well.
Reported-by: Noriyoshi Shinoda
Author: Noriyoshi Shinoda
Reviewed-by: Sawada Masahiko and Amit Kapila
Discussion: https://postgr.es/m/CA+fd4k5_pPAYRTDrO2PbtTOe0eHQpBvuqmCr8ic39uTNmR49Eg@mail.gmail.com
The test cases added by that commit were trying to test the exact number of
times a particular transaction has spilled. However, that number can vary if
any background transaction (say by autovacuum) happens in parallel to the main
transaction. So let's not try to verify the exact count.
Author: Amit Kapila
Reviewed-by: Sawada Masahiko
Discussion: https://postgr.es/m/CA+fd4k5_pPAYRTDrO2PbtTOe0eHQpBvuqmCr8ic39uTNmR49Eg@mail.gmail.com
REPLICA IDENTITY USING INDEX behaves the same way as NOTHING if the
associated index is dropped, even if there is a primary key that could
be used as a fallback for the changes generated. There have never been
any tests to cover such scenarios, so this commit closes the gap.
Author: Michael Paquier
Reviewed-by: Masahiko Sawada, Rahila Syed, Euler Taveira
Discussion: https://postgr.es/m/20200522035028.GO2355@paquier.xyz
Commit 7259736a6e added the capability to stream changes in ReorderBuffer
which has some tests to test the streaming mode. It is quite possible that
while this test is running a parallel transaction could be logged by
autovacuum. Such a transaction won't perform any insert/update/delete to
non-catalog tables so will be shown as an empty transaction. Fix it by
skipping the empty transactions during this test.
Per report by buildfarm.
Instead of serializing the transaction to disk after reaching the
logical_decoding_work_mem limit in memory, we consume the changes we have
in memory and invoke stream API methods added by commit 45fdc9738b.
However, sometimes if we have incomplete toast or speculative insert we
spill to the disk because we can't generate the complete tuple and stream.
And, as soon as we get the complete tuple we stream the transaction
including the serialized changes.
We can do this incremental processing thanks to having assignments
(associating subxact with toplevel xacts) in WAL right away, and
thanks to logging the invalidation messages at each command end. These
features are added by commits 0bead9af48 and c55040ccd0 respectively.
Now that we can stream in-progress transactions, the concurrent aborts
may cause failures when the output plugin consults catalogs (both system
and user-defined).
We handle such failures by returning ERRCODE_TRANSACTION_ROLLBACK
sqlerrcode from system table scan APIs to the backend or WALSender
decoding a specific uncommitted transaction. The decoding logic on the
receipt of such a sqlerrcode aborts the decoding of the current
transaction and continue with the decoding of other transactions.
We have ReorderBufferTXN pointer in each ReorderBufferChange by which we
know which xact it belongs to. The output plugin can use this to decide
which changes to discard in case of stream_abort_cb (e.g. when a subxact
gets discarded).
We also provide a new option via SQL APIs to fetch the changes being
streamed.
Author: Dilip Kumar, Tomas Vondra, Amit Kapila, Nikhil Sontakke
Reviewed-by: Amit Kapila, Kuntal Ghosh, Ajin Cherian
Tested-by: Neha Sharma, Mahendra Singh Thalor and Ajin Cherian
Discussion: https://postgr.es/m/688b0b7f-2f6c-d827-c27b-216a8e3ea700@2ndquadrant.com
This patch removes the hardcoded check for superuser privileges when
executing replication origin functions. Instead, execution is revoked
from public, meaning that those functions can be executed by a superuser
and that access to them can be granted.
Author: Martín Marqués
Reviewed-by: Kyotaro Horiguchi, Michael Paquier, Masahiko Sawada
Discussion: https:/postgr.es/m/CAPdiE1xJMZOKQL3dgHMUrPqysZkgwzSMXETfKkHYnBAB7-0VRQ@mail.gmail.com
The txid_XXX family of fmgr functions exposes 64 bit transaction IDs to
users as int8. Now that we have an SQL type xid8 for FullTransactionId,
define a new set of functions including pg_current_xact_id() and
pg_current_snapshot() based on that. Keep the old functions around too,
for now.
It's a bit sneaky to use the same C functions for both, but since the
binary representation is identical except for the signedness of the
type, and since older functions are the ones using the wrong signedness,
and since we'll presumably drop the older ones after a reasonable period
of time, it seems reasonable to switch to FullTransactionId internally
and share the code for both.
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: Takao Fujii <btfujiitkp@oss.nttdata.com>
Reviewed-by: Yoshikazu Imai <imai.yoshikazu@fujitsu.com>
Reviewed-by: Mark Dilger <mark.dilger@enterprisedb.com>
Discussion: https://postgr.es/m/20190725000636.666m5mad25wfbrri%40alap3.anarazel.de
In commit 18555b132 we tentatively established a rule that regression
tests should use names containing "regression" for databases, and names
starting with "regress_" for all other globally-visible object names, so
as to circumscribe the side-effects that "make installcheck" could have on
an existing installation. However, no enforcement mechanism was created,
so it's unsurprising that some new violations have crept in since then.
In fact, a whole new *category* of violations has crept in, to wit we now
also have globally-visible subscription and replication origin names, and
"make installcheck" could very easily clobber user-created objects of
those types. So it's past time to do something about this.
This commit sanitizes the tests enough that they will pass (i.e. not
generate any visible warnings) with the enforcement mechanism I'll add
in the next commit. There are some TAP tests that still trigger the
warnings, but the warnings do not cause test failure. Since these tests
do not actually run against a pre-existing installation, there's no need
to worry whether they could conflict with user-created objects.
The problem with rolenames.sql testing special role names like "user"
is still there, and is dealt with only very cosmetically in this patch
(by hiding the warnings :-(). What we actually need to do to be safe is
to take that test script out of "make installcheck" altogether, but that
seems like material for a separate patch.
Discussion: https://postgr.es/m/16638.1468620817@sss.pgh.pa.us
When reindexing individual indexes on pg_class it was possible to
either trigger an assertion failure:
TRAP: FailedAssertion("!(!ReindexIsProcessingIndex(((index)->rd_id)))
That's because reindex_index() called SetReindexProcessing() - which
enables an asserts ensuring no index insertions happen into the index
- before calling RelationSetNewRelfilenode(). That not correct for
indexes on pg_class, because RelationSetNewRelfilenode() updates the
relevant pg_class row, which needs to update the indexes.
The are two reasons this wasn't noticed earlier. Firstly the bug
doesn't trigger when reindexing all of pg_class, as reindex_relation
has code "hiding" all yet-to-be-reindexed indexes. Secondly, the bug
only triggers when the the update to pg_class doesn't turn out to be a
HOT update - otherwise there's no index insertion to trigger the
bug. Most of the time there's enough space, making this bug hard to
trigger.
To fix, move RelationSetNewRelfilenode() to before the
SetReindexProcessing() (and, together with some other code, to outside
of the PG_TRY()).
To make sure the error checking intended by SetReindexProcessing() is
more robust, modify CatalogIndexInsert() to check
ReindexIsProcessingIndex() even when the update is a HOT update.
Also add a few regression tests for REINDEXing of system catalogs.
The last two improvements would have prevented some of the issues
fixed in 5c1560606d from being introduced in the first place.
Reported-By: Michael Paquier
Diagnosed-By: Tom Lane and Andres Freund
Author: Andres Freund
Reviewed-By: Tom Lane
Discussion: https://postgr.es/m/20190418011430.GA19133@paquier.xyz
Backpatch: 9.4-, the bug is present in all branches
This allows the user to create duplicates of existing replication slots,
either logical or physical, and even changing properties such as whether
they are temporary or the output plugin used.
There are multiple uses for this, such as initializing multiple replicas
using the slot for one base backup; when doing investigation of logical
replication issues; and to select a different output plugins.
Author: Masahiko Sawada
Reviewed-by: Michael Paquier, Andres Freund, Petr Jelinek
Discussion: https://postgr.es/m/CAD21AoAm7XX8y_tOPP6j4Nzzch12FvA1wPqiO690RCk+uYVstg@mail.gmail.com
Ever since its birth, ReorderBufferBuildTupleCidHash() has contained an
assertion that a catalog tuple cannot change Cmax after acquiring one. But
that's wrong: if a subtransaction executes DDL that affects that catalog
tuple, and later aborts and another DDL affects the same tuple, it will
change Cmax. Relax the assertion to merely verify that the Cmax remains
valid and monotonically increasing, instead.
Add a test that tickles the relevant code.
Diagnosed by, and initial patch submitted by: Arseny Sher
Co-authored-by: Arseny Sher
Discussion: https://postgr.es/m/874l9p8hyw.fsf@ars-thinkpad
Repeatedly rewriting a mapped catalog table with VACUUM FULL or
CLUSTER could cause logical decoding to fail with:
ERROR, "could not map filenode \"%s\" to relation OID"
To trigger the problem the rewritten catalog had to have live tuples
with toasted columns.
The problem was triggered as during catalog table rewrites the
heap_insert() check that prevents logical decoding information to be
emitted for system catalogs, failed to treat the new heap's toast table
as a system catalog (because the new heap is not recognized as a
catalog table via RelationIsLogicallyLogged()). The relmapper, in
contrast to the normal catalog contents, does not contain historical
information. After a single rewrite of a mapped table the new relation
is known to the relmapper, but if the table is rewritten twice before
logical decoding occurs, the relfilenode cannot be mapped to a
relation anymore. Which then leads us to error out. This only
happens for toast tables, because the main table contents aren't
re-inserted with heap_insert().
The fix is simple, add a new heap_insert() flag that prevents logical
decoding information from being emitted, and accept during decoding
that there might not be tuple data for toast tables.
Unfortunately that does not fix pre-existing logical decoding
errors. Doing so would require not throwing an error when a filenode
cannot be mapped to a relation during decoding, and that seems too
likely to hide bugs. If it's crucial to fix decoding for an existing
slot, temporarily changing the ERROR in ReorderBufferCommit() to a
WARNING appears to be the best fix.
Author: Andres Freund
Discussion: https://postgr.es/m/20180914021046.oi7dm4ra3ot2g2kt@alap3.anarazel.de
Backpatch: 9.4-, where logical decoding was introduced
Masahiko Sawada