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path: root/src/backend/replication/logical/tablesync.c
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2025-09-08Post-commit review fixes for 228c370868.Amit Kapila
This commit fixes three issues: 1) When a disabled subscription is created with retain_dead_tuples set to true, the launcher is not woken up immediately, which may lead to delays in creating the conflict detection slot. Creating the conflict detection slot is essential even when the subscription is not enabled. This ensures that dead tuples are retained, which is necessary for accurately identifying the type of conflict during replication. 2) Conflict-related data was unnecessarily retained when the subscription does not have a table. 3) Conflict-relevant data could be prematurely removed before applying prepared transactions on the publisher that are in the commit critical section. This issue occurred because the backend executing COMMIT PREPARED was not accounted for during the computation of oldestXid in the commit phase on the publisher. As a result, the subscriber could advance the conflict slot's xmin without waiting for such COMMIT PREPARED transactions to complete. We fixed this issue by identifying prepared transactions that are in the commit critical section during computation of oldestXid in commit phase. Author: Zhijie Hou <houzj.fnst@fujitsu.com> Reviewed-by: shveta malik <shveta.malik@gmail.com> Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com> Reviewed-by: Nisha Moond <nisha.moond412@gmail.com> Reviewed-by: Amit Kapila <amit.kapila16@gmail.com> Discussion: https://postgr.es/m/OS9PR01MB16913DACB64E5721872AA5C02943BA@OS9PR01MB16913.jpnprd01.prod.outlook.com Discussion: https://postgr.es/m/OS9PR01MB16913F67856B0DA2A909788129400A@OS9PR01MB16913.jpnprd01.prod.outlook.com
2025-08-01Fix a deadlock during ALTER SUBSCRIPTION ... DROP PUBLICATION.Amit Kapila
A deadlock can occur when the DDL command and the apply worker acquire catalog locks in different orders while dropping replication origins. The issue is rare in PG16 and higher branches because, in most cases, the tablesync worker performs the origin drop in those branches, and its locking sequence does not conflict with DDL operations. This patch ensures consistent lock acquisition to prevent such deadlocks. As per buildfarm. Reported-by: Alexander Lakhin <exclusion@gmail.com> Author: Ajin Cherian <itsajin@gmail.com> Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com> Reviewed-by: vignesh C <vignesh21@gmail.com> Reviewed-by: Amit Kapila <amit.kapila16@gmail.com> Backpatch-through: 14, where it was introduced Discussion: https://postgr.es/m/bab95e12-6cc5-4ebb-80a8-3e41956aa297@gmail.com
2025-07-23Preserve conflict-relevant data during logical replication.Amit Kapila
Logical replication requires reliable conflict detection to maintain data consistency across nodes. To achieve this, we must prevent premature removal of tuples deleted by other origins and their associated commit_ts data by VACUUM, which could otherwise lead to incorrect conflict reporting and resolution. This patch introduces a mechanism to retain deleted tuples on the subscriber during the application of concurrent transactions from remote nodes. Retaining these tuples allows us to correctly ignore concurrent updates to the same tuple. Without this, an UPDATE might be misinterpreted as an INSERT during resolutions due to the absence of the original tuple. Additionally, we ensure that origin metadata is not prematurely removed by vacuum freeze, which is essential for detecting update_origin_differs and delete_origin_differs conflicts. To support this, a new replication slot named pg_conflict_detection is created and maintained by the launcher on the subscriber. Each apply worker tracks its own non-removable transaction ID, which the launcher aggregates to determine the appropriate xmin for the slot, thereby retaining necessary tuples. Conflict information retention (deleted tuples and commit_ts) can be enabled per subscription via the retain_conflict_info option. This is disabled by default to avoid unnecessary overhead for configurations that do not require conflict resolution or logging. During upgrades, if any subscription on the old cluster has retain_conflict_info enabled, a conflict detection slot will be created to protect relevant tuples from deletion when the new cluster starts. This is a foundational work to correctly detect update_deleted conflict which will be done in a follow-up patch. Author: Zhijie Hou <houzj.fnst@fujitsu.com> Reviewed-by: shveta malik <shveta.malik@gmail.com> Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com> Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com> Reviewed-by: Nisha Moond <nisha.moond412@gmail.com> Reviewed-by: Amit Kapila <amit.kapila16@gmail.com> Discussion: https://postgr.es/m/OS0PR01MB5716BE80DAEB0EE2A6A5D1F5949D2@OS0PR01MB5716.jpnprd01.prod.outlook.com
2025-07-07Standardize LSN formatting by zero paddingÁlvaro Herrera
This commit standardizes the output format for LSNs to ensure consistent representation across various tools and messages. Previously, LSNs were inconsistently printed as `%X/%X` in some contexts, while others used zero-padding. This often led to confusion when comparing. To address this, the LSN format is now uniformly set to `%X/%08X`, ensuring the lower 32-bit part is always zero-padded to eight hexadecimal digits. Author: Japin Li <japinli@hotmail.com> Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com> Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de> Discussion: https://postgr.es/m/ME0P300MB0445CA53CA0E4B8C1879AF84B641A@ME0P300MB0445.AUSP300.PROD.OUTLOOK.COM
2025-06-24Prevent excessive delays before launching new logrep workers.Tom Lane
The logical replication launcher process would sometimes sleep for as much as 3 minutes before noticing that it is supposed to launch a new worker. This could happen if (1) WaitForReplicationWorkerAttach absorbed a process latch wakeup that was meant to cause ApplyLauncherMain to do work, or (2) logicalrep_worker_launch reported failure, either because of resource limits or because the new worker terminated immediately. In case (2), the expected behavior is that we retry the launch after wal_retrieve_retry_interval, but that didn't reliably happen. It's not clear how often such conditions would occur in the field, but in our subscription test suite they are somewhat common, especially in tests that exercise cases that cause quick worker failure. That causes the tests to take substantially longer than they ought to do on typical setups. To fix (1), make WaitForReplicationWorkerAttach re-set the latch before returning if it cleared it while looping. To fix (2), ensure that we reduce wait_time to no more than wal_retrieve_retry_interval when logicalrep_worker_launch reports failure. In passing, fix a couple of perhaps-hypothetical race conditions, e.g. examining worker->in_use without a lock. Backpatch to v16. Problem (2) didn't exist before commit 5a3a95385 because the previous code always set wait_time to wal_retrieve_retry_interval when launching a worker, regardless of success or failure of the launch. That behavior also greatly mitigated problem (1), so I'm not excited about adapting the remainder of the patch to the substantially-different code in older branches. Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Amit Kapila <amit.kapila16@gmail.com> Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com> Discussion: https://postgr.es/m/817604.1750723007@sss.pgh.pa.us Backpatch-through: 16
2025-04-11Improve various new-to-v18 appendStringInfo callsDavid Rowley
Similar to 8461424fd, here we adjust a few new locations which were not using the most suitable appendStringInfo* function for the intended purpose. Author: David Rowley <drowleyml@gmail.com Discussion: https://postgr.es/m/CAApHDvqJnNjueb=Eoj8K+8n0g7nj_AcPWSiCj5RNV4fDejAfqA@mail.gmail.com
2025-03-13pg_noreturn to replace pg_attribute_noreturn()Peter Eisentraut
We want to support a "noreturn" decoration on more compilers besides just GCC-compatible ones, but for that we need to move the decoration in front of the function declaration instead of either behind it or wherever, which is the current style afforded by GCC-style attributes. Also rename the macro to "pg_noreturn" to be similar to the C11 standard "noreturn". pg_noreturn is now supported on all compilers that support C11 (using _Noreturn), as well as GCC-compatible ones (using __attribute__, as before), as well as MSVC (using __declspec). (When PostgreSQL requires C11, the latter two variants can be dropped.) Now, all supported compilers effectively support pg_noreturn, so the extra code for !HAVE_PG_ATTRIBUTE_NORETURN can be dropped. This also fixes a possible problem if third-party code includes stdnoreturn.h, because then the current definition of #define pg_attribute_noreturn() __attribute__((noreturn)) would cause an error. Note that the C standard does not support a noreturn attribute on function pointer types. So we have to drop these here. There are only two instances at this time, so it's not a big loss. In one case, we can make up for it by adding the pg_noreturn to a wrapper function and adding a pg_unreachable(), in the other case, the latter was already done before. Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://www.postgresql.org/message-id/flat/pxr5b3z7jmkpenssra5zroxi7qzzp6eswuggokw64axmdixpnk@zbwxuq7gbbcw
2025-01-01Update copyright for 2025Bruce Momjian
Backpatch-through: 13
2024-11-28Remove useless casts to (void *)Peter Eisentraut
Many of them just seem to have been copied around for no real reason. Their presence causes (small) risks of hiding actual type mismatches or silently discarding qualifiers Discussion: https://www.postgresql.org/message-id/flat/461ea37c-8b58-43b4-9736-52884e862820@eisentraut.org
2024-10-30Replicate generated columns when specified in the column list.Amit Kapila
This commit allows logical replication to publish and replicate generated columns when explicitly listed in the column list. We also ensured that the generated columns were copied during the initial tablesync when they were published. We will allow to replicate generated columns even when they are not specified in the column list (via a new publication option) in a separate commit. The motivation of this work is to allow replication for cases where the client doesn't have generated columns. For example, the case where one is trying to replicate data from Postgres to the non-Postgres database. Author: Shubham Khanna, Vignesh C, Hou Zhijie Reviewed-by: Peter Smith, Hayato Kuroda, Shlok Kyal, Amit Kapila Discussion: https://postgr.es/m/B80D17B2-2C8E-4C7D-87F2-E5B4BE3C069E@gmail.com
2024-10-25Refactor code converting a publication name List to a StringInfoMichael Paquier
The existing get_publications_str() is renamed to GetPublicationsStr() and is moved to pg_subscription.c, so as it is possible to reuse it at two locations of the tablesync code where the same logic was duplicated. fetch_remote_table_info() was doing two List->StringInfo conversions when dealing with a server of version 15 or newer. The conversion happens only once now. This refactoring leads to less code overall. Author: Peter Smith Reviewed-by: Michael Paquier, Masahiko Sawada Discussion: https://postgr.es/m/CAHut+PtJMk4bKXqtpvqVy9ckknCgK9P6=FeG8zHF=6+Em_Snpw@mail.gmail.com
2024-07-11Improve logical replication connection-failure messages.Tom Lane
These messages mostly said "could not connect to the publisher: %s" which is lacking context. Add some verbiage to indicate which subscription or worker process is failing. Nisha Moond Discussion: https://postgr.es/m/CABdArM7q1=zqL++cYd0hVMg3u_tc0S=0Of=Um-KvDhLony0cSg@mail.gmail.com
2024-04-25Fix the missing table sync due to improper invalidation handling.Amit Kapila
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
2024-04-10Fixup various StringInfo function usagesDavid Rowley
This adjusts various appendStringInfo* function calls to use a more appropriate and efficient function with the same behavior. For example, use appendStringInfoChar() when appending a single character rather than appendStringInfo() and appendStringInfoString() when no formatting is required rather than using appendStringInfo(). All adjustments made here are in code that's new to v17, so it makes sense to fix these now rather than wait a few years and make backpatching harder. Discussion: https://postgr.es/m/CAApHDvojY2UvMiO+9_55ArTj10P1LBNJyyoGB+C65BLDNT0GsQ@mail.gmail.com Reviewed-by: Nathan Bossart, Tom Lane
2024-03-13Make the order of the header file includes consistentPeter Eisentraut
Similar to commit 7e735035f20. Author: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/CAMbWs4-WhpCFMbXCjtJ%2BFzmjfPrp7Hw1pk4p%2BZpU95Kh3ofZ1A%40mail.gmail.com
2024-02-05Enhance libpqrcv APIs to support slot synchronization.Amit Kapila
This patch provides support for regular (non-replication) connections in libpqrcv_connect(). This can be used to execute SQL statements on the primary server without starting a walsender. A new API libpqrcv_get_dbname_from_conninfo() is also added to extract the database name from the given connection-info. Note that this patch doesn't change any existing functionality but later patches implementing the slot synchronization will use this functionality to connect to the primary server to fetch required slot information. Author: Shveta Malik, Hou Zhijie, 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
2024-01-30Add a failover option to subscriptions.Amit Kapila
This commit introduces a new subscription option named 'failover', which provides users with the ability to set the failover property of the replication slot on the publisher when creating or altering a subscription. This uses the replication commands introduced by commit 7329240437 to enable the failover option for a logical replication slot. If the failover option is set to true, the associated replication slots (i.e. the main slot and the table sync slots) in the upstream database are enabled to be synchronized to the standbys. Note that the capability to sync the replication slots will be added in subsequent commits. Thanks to Masahiko Sawada for the design inputs. Author: Shveta Malik, Hou Zhijie, 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
2024-01-29Allow setting failover property in the replication command.Amit Kapila
This commit implements a new replication command called ALTER_REPLICATION_SLOT and a corresponding walreceiver API function named walrcv_alter_slot. Additionally, the CREATE_REPLICATION_SLOT command has been extended to support the failover option. These new additions allow the modification of the failover property of a replication slot on the publisher. A subsequent commit will make use of these commands in subscription commands and will add the tests as well to cover the functionality added/changed by this commit. Author: Hou Zhijie, Shveta Malik 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
2024-01-04Add macros for looping through a List without a ListCell.Nathan Bossart
Many foreach loops only use the ListCell pointer to retrieve the content of the cell, like so: ListCell *lc; foreach(lc, mylist) { int myint = lfirst_int(lc); ... } This commit adds a few convenience macros that automatically declare the loop variable and retrieve the current cell's contents. This allows us to rewrite the previous loop like this: foreach_int(myint, mylist) { ... } This commit also adjusts a few existing loops in order to add coverage for the new/adjusted macros. There is presently no plan to bulk update all foreach loops, as that could introduce a significant amount of back-patching pain. Instead, these macros are primarily intended for use in new code. Author: Jelte Fennema-Nio Reviewed-by: David Rowley, Alvaro Herrera, Vignesh C, Tom Lane Discussion: https://postgr.es/m/CAGECzQSwXKnxGwW1_Q5JE%2B8Ja20kyAbhBHO04vVrQsLcDciwXA%40mail.gmail.com
2024-01-03Update copyright for 2024Bruce Momjian
Reported-by: Michael Paquier Discussion: https://postgr.es/m/ZZKTDPxBBMt3C0J9@paquier.xyz Backpatch-through: 12
2023-12-11Fix an undetected deadlock due to apply worker.Amit Kapila
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
2023-11-22Fix the initial sync tables with no columns.Amit Kapila
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
2023-10-17Restart the apply worker if the privileges have been revoked.Amit Kapila
Restart the apply worker if the subscription owner's superuser privileges have been revoked. This is required so that the subscription connection string gets revalidated and use the password option to connect to the publisher for non-superusers, if required. Author: Vignesh C Reviewed-by: Amit Kapila Discussion: http://postgr.es/m/CALDaNm2Dxmhq08nr4P6G+24QvdBo_GAVyZ_Q1TcGYK+8NHs9xw@mail.gmail.com
2023-08-22Simplify the logical worker type checks by using the switch on worker type.Amit Kapila
The current code uses if/else statements at various places to take worker specific actions. Change those to use the switch on worker type added by commit 2a8b40e368. This makes code easier to read and understand. Author: Peter Smith Reviewed-by: Amit Kapila, Hou Zhijie Discussion: http://postgr.es/m/CAHut+PttPSuP0yoZ=9zLDXKqTJ=d0bhxwKaEaNcaym1XqcvDEg@mail.gmail.com
2023-08-14Simplify determining logical replication worker types.Amit Kapila
We deduce a LogicalRepWorker's type from the values of several different fields ('relid' and 'leader_pid') whenever logic needs to know it. In fact, the logical replication worker type is already known at the time of launching the LogicalRepWorker and it never changes for the lifetime of that process. Instead of deducing the type, it is simpler to just store it one time, and access it directly thereafter. Author: Peter Smith Reviewed-by: Amit Kapila, Bharath Rupireddy Discussion: http://postgr.es/m/CAHut+PttPSuP0yoZ=9zLDXKqTJ=d0bhxwKaEaNcaym1XqcvDEg@mail.gmail.com
2023-08-03Refactor to split Apply and Tablesync Workers code.Amit Kapila
Both apply and tablesync workers were using ApplyWorkerMain() as entry point. As the name implies, ApplyWorkerMain() should be considered as the main function for apply workers. Tablesync worker's path was hidden and does not have enough in common to share the same main function with apply worker. Also, most of the code shared by both worker types is already combined in LogicalRepApplyLoop(). There is no need to combine the rest in ApplyWorkerMain() anymore. This patch introduces TablesyncWorkerMain() as a new entry point for tablesync workers. This aims to increase code readability and would help with future improvements like the reuse of tablesync workers in the initial synchronization. Author: Melih Mutlu based on suggestions by Melanie Plageman Reviewed-by: Peter Smith, Kuroda Hayato, Amit Kapila Discussion: http://postgr.es/m/CAGPVpCTq=rUDd4JUdaRc1XUWf4BrH2gdSNf3rtOMUGj9rPpfzQ@mail.gmail.com
2023-06-20Pre-beta2 mechanical code beautification.Tom Lane
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
2023-06-15Fix possible crash in tablesync worker.Amit Kapila
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
2023-06-09Honor run_as_owner option in tablesync worker.Masahiko Sawada
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
2023-05-19Pre-beta mechanical code beautification.Tom Lane
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
2023-04-19Fix various typos and incorrect/outdated name referencesDavid Rowley
Author: Alexander Lakhin Discussion: https://postgr.es/m/699beab4-a6ca-92c9-f152-f559caf6dc25@gmail.com
2023-03-30Add new predefined role pg_create_subscription.Robert Haas
This role can be granted to non-superusers to allow them to issue CREATE SUBSCRIPTION. The non-superuser must additionally have CREATE permissions on the database in which the subscription is to be created. Most forms of ALTER SUBSCRIPTION, including ALTER SUBSCRIPTION .. SKIP, now require only that the role performing the operation own the subscription, or inherit the privileges of the owner. However, to use ALTER SUBSCRIPTION ... RENAME or ALTER SUBSCRIPTION ... OWNER TO, you also need CREATE permission on the database. This is similar to what we do for schemas. To change the owner of a schema, you must also have permission to SET ROLE to the new owner, similar to what we do for other object types. Non-superusers are required to specify a password for authentication and the remote side must use the password, similar to what is required for postgres_fdw and dblink. A superuser who wants a non-superuser to own a subscription that does not rely on password authentication may set the new password_required=false property on that subscription. A non-superuser may not set password_required=false and may not modify a subscription that already has password_required=false. This new password_required subscription property works much like the eponymous postgres_fdw property. In both cases, the actual semantics are that a password is not required if either (1) the property is set to false or (2) the relevant user is the superuser. Patch by me, reviewed by Andres Freund, Jeff Davis, Mark Dilger, and Stephen Frost (but some of those people did not fully endorse all of the decisions that the patch makes). Discussion: http://postgr.es/m/CA+TgmoaDH=0Xj7OBiQnsHTKcF2c4L+=gzPBUKSJLh8zed2_+Dg@mail.gmail.com
2023-03-23Allow logical replication to copy tables in binary format.Amit Kapila
This patch allows copying tables in the binary format during table synchronization when the binary option for a subscription is enabled. Previously, tables are copied in text format even if the subscription is created with the binary option enabled. Copying tables in binary format may reduce the time spent depending on column types. A binary copy for initial table synchronization is supported only when both publisher and subscriber are v16 or later. Author: Melih Mutlu Reviewed-by: Peter Smith, Shi yu, Euler Taveira, Vignesh C, Kuroda Hayato, Osumi Takamichi, Bharath Rupireddy, Hou Zhijie Discussion: https://postgr.es/m/CAGPVpCQvAziCLknEnygY0v1-KBtg%2BOm-9JHJYZOnNPKFJPompw%40mail.gmail.com
2023-01-24Fix the Drop Database hang.Amit Kapila
The drop database command waits for the logical replication sync worker to accept ProcSignalBarrier and the worker's slot creation waits for the drop database to finish which leads to a deadlock. This happens because the tablesync worker holds interrupts while creating a slot. We prevent cancel/die interrupts while creating a slot in the table sync worker because it is possible that before the server finishes this command, a concurrent drop subscription happens which would complete without removing this slot and that leads to the slot existing until the end of walsender. However, the slot will eventually get dropped at the walsender exit time, so there is no danger of the dangling slot. This patch reallows cancel/die interrupts while creating a slot and modifies the test to wait for slots to become zero to prevent finding an ephemeral slot. The reported hang doesn't happen in PG14 as the drop database starts to wait for ProcSignalBarrier with PG15 (commits 4eb2176318 and e2f65f4255) but it is good to backpatch this till PG14 as it is not a good idea to prevent interrupts during a network call that could block indefinitely. Reported-by: Lakshmi Narayanan Sreethar Diagnosed-by: Andres Freund Author: Hou Zhijie Reviewed-by: Vignesh C, Amit Kapila Backpatch-through: 14, where it was introduced in commit 6b67d72b60 Discussion: https://postgr.es/m/CA+kvmZELXQ4ZD3U=XCXuG3KvFgkuPoN1QrEj8c-rMRodrLOnsg@mail.gmail.com
2023-01-22Track logrep apply workers' last start times to avoid useless waits.Tom Lane
Enforce wal_retrieve_retry_interval on a per-subscription basis, rather than globally, and arrange to skip that delay in case of an intentional worker exit. This probably makes little difference in the field, where apply workers wouldn't be restarted often; but it has a significant impact on the runtime of our logical replication regression tests (even though those tests use artificially-small wal_retrieve_retry_interval settings already). Nathan Bossart, with mostly-cosmetic editorialization by me Discussion: https://postgr.es/m/20221122004119.GA132961@nathanxps13
2023-01-09Perform apply of large transactions by parallel workers.Amit Kapila
Currently, for large transactions, the publisher sends the data in multiple streams (changes divided into chunks depending upon logical_decoding_work_mem), and then on the subscriber-side, the apply worker writes the changes into temporary files and once it receives the commit, it reads from those files and applies the entire transaction. To improve the performance of such transactions, we can instead allow them to be applied via parallel workers. In this approach, we assign a new parallel apply worker (if available) as soon as the xact's first stream is received and the leader apply worker will send changes to this new worker via shared memory. The parallel apply worker will directly apply the change instead of writing it to temporary files. However, if the leader apply worker times out while attempting to send a message to the parallel apply worker, it will switch to "partial serialize" mode - in this mode, the leader serializes all remaining changes to a file and notifies the parallel apply workers to read and apply them at the end of the transaction. We use a non-blocking way to send the messages from the leader apply worker to the parallel apply to avoid deadlocks. We keep this parallel apply assigned till the transaction commit is received and also wait for the worker to finish at commit. This preserves commit ordering and avoid writing to and reading from files in most cases. We still need to spill if there is no worker available. This patch also extends the SUBSCRIPTION 'streaming' parameter so that the user can control whether to apply the streaming transaction in a parallel apply worker or spill the change to disk. The user can set the streaming parameter to 'on/off', or 'parallel'. The parameter value 'parallel' means the streaming will be applied via a parallel apply worker, if available. The parameter value 'on' means the streaming transaction will be spilled to disk. The default value is 'off' (same as current behaviour). In addition, the patch extends the logical replication STREAM_ABORT message so that abort_lsn and abort_time can also be sent which can be used to update the replication origin in parallel apply worker when the streaming transaction is aborted. Because this message extension is needed to support parallel streaming, parallel streaming is not supported for publications on servers < PG16. Author: Hou Zhijie, Wang wei, Amit Kapila with design inputs from Sawada Masahiko Reviewed-by: Sawada Masahiko, Peter Smith, Dilip Kumar, Shi yu, Kuroda Hayato, Shveta Mallik Discussion: https://postgr.es/m/CAA4eK1+wyN6zpaHUkCLorEWNx75MG0xhMwcFhvjqm2KURZEAGw@mail.gmail.com
2023-01-06Check for two_phase change at end of process_syncing_tables_for_apply.Tom Lane
Previously this function checked to see if we were ready to switch to two_phase mode at its start, but that's silly: we should check at the end, after we've done the work that might make us ready. This simple change removes one sleep cycle from the time needed to switch to two_phase mode. In the real world that might not be worth much, but it shaves a few seconds off the runtime for the subscription test suite. Nathan Bossart Discussion: https://postgr.es/m/20221122004119.GA132961@nathanxps13
2023-01-02Update copyright for 2023Bruce Momjian
Backpatch-through: 11
2022-10-11Add a common function to generate the origin name.Amit Kapila
Make a common replication origin name formatting function to replace multiple snprintf() expressions. This also includes logic previously done by ReplicationOriginNameForTablesync(). This makes the code to generate the origin name consistent among apply worker and tablesync worker. Author: Peter Smith Reviewed-By: Aleksander Alekseev Discussion: https://postgr.es/m/CAHut%2BPsa8hhfSE6ozUK-ih7GkQziAVAf4f3bqiXEj2nQiu-43g%40mail.gmail.com
2022-09-30Fix tab-completion after commit 790bf615ddbaAlvaro Herrera
I (Álvaro) broke tab-completion for GRANT .. ALL TABLES IN SCHEMA while removing ALL from the publication syntax for schemas in the aforementioned commit. I also missed to update a bunch of tab-completion rules for ALTER/CREATE PUBLICATION that match each individual piece of ALL TABLES IN SCHEMA. Repair those bugs. While fixing up that commit, update a couple of outdated comments related to the same change. Backpatch to 15. Author: Shi yu <shiy.fnst@fujitsu.com> Reviewed-by: Peter Smith <smithpb2250@gmail.com> Discussion: https://postgr.es/m/OSZPR01MB6310FCE8609185A56344EED2FD559@OSZPR01MB6310.jpnprd01.prod.outlook.com
2022-09-24Message style improvementsPeter Eisentraut
2022-09-21Pass Size as a 2nd argument for snprintf() in tablesync.c.Amit Kapila
Previously the following snprintf() wrappers: * ReplicationSlotNameForTablesync() * ReplicationOriginNameForTablesync() ... used int as a second argument of snprintf() while the actual type of it is size_t. Although it doesn't fail at present better replace it with Size for consistency with the rest of the system. Author: Aleksander Alekseev Reviewed-By: Peter Smith Discussion: https://postgr.es/m/CAHut%2BPsa8hhfSE6ozUK-ih7GkQziAVAf4f3bqiXEj2nQiu-43g%40mail.gmail.com
2022-09-12Make the tablesync worker's replication origin drop logic robust.Amit Kapila
In commit f6c5edb8ab, we started to drop the replication origin slots before tablesync worker exits to avoid consuming more slots than required. We were dropping the replication origin in the same transaction where we were marking the tablesync state as SYNCDONE. Now, if there is any error after we have dropped the origin but before we commit the containing transaction, the in-memory state of replication progress won't be rolled back. Due to this, after the restart, tablesync worker can start streaming from the wrong location and can apply the already processed transaction. To fix this, we need to opportunistically drop the origin after marking the tablesync state as SYNCDONE. Even, if the tablesync worker fails to remove the replication origin before exit, the apply worker ensures to clean it up afterward. Reported by Tom Lane as per buildfarm. Diagnosed-by: Masahiko Sawada Author: Hou Zhijie Reviewed-By: Masahiko Sawada, Amit Kapila Discussion: https://postgr.es/m/20220714115155.GA5439@depesz.com Discussion: https://postgr.es/m/CAD21AoAw0Oofi4kiDpJBOwpYyBBBkJj=sLUOn4Gd2GjUAKG-fw@mail.gmail.com
2022-09-06Fix an assortment of improper usages of string functionsDavid Rowley
In a similar effort to f736e188c and 110d81728, fixup various usages of string functions where a more appropriate function is available and more fit for purpose. These changes include: 1. Use cstring_to_text_with_len() instead of cstring_to_text() when working with a StringInfoData and the length can easily be obtained. 2. Use appendStringInfoString() instead of appendStringInfo() when no formatting is required. 3. Use pstrdup(...) instead of psprintf("%s", ...) 4. Use pstrdup(...) instead of psprintf(...) (with no formatting) 5. Use appendPQExpBufferChar() instead of appendPQExpBufferStr() when the length of the string being appended is 1. 6. appendStringInfoChar() instead of appendStringInfo() when no formatting is required and string is 1 char long. 7. Use appendPQExpBufferStr(b, .) instead of appendPQExpBuffer(b, "%s", .) 8. Don't use pstrdup when it's fine to just point to the string constant. I (David) did find other cases of #8 but opted to use #4 instead as I wasn't certain enough that applying #8 was ok (e.g in hba.c) Author: Ranier Vilela, David Rowley Discussion: https://postgr.es/m/CAApHDvo2j2+RJBGhNtUz6BxabWWh2Jx16wMUMWKUjv70Ver1vg@mail.gmail.com
2022-08-30Drop replication origin slots before tablesync worker exits.Amit Kapila
Currently, the replication origin tracking of the tablesync worker is dropped by the apply worker. So, there will be a small lag between the tablesync worker exit and its origin tracking got removed. In the meantime, new tablesync workers can be launched and will try to set up a new origin tracking. This can lead the system to reach max configured limit (max_replication_slots) even if the user has configured the max limit considering the number of tablesync workers required in the system. We decided not to back-patch as this can occur in very narrow circumstances and users have to option to increase the configured limit by increasing max_replication_slots. Reported-by: Hubert Depesz Lubaczewski Author: Ajin Cherian Reviwed-by: Masahiko Sawada, Peter Smith, Hou Zhijie, Amit Kapila Discussion: https://postgr.es/m/20220714115155.GA5439@depesz.com
2022-08-20Remove shadowed local variables that are new in v15David Rowley
Compiling with -Wshadow=compatible-local yields quite a few warnings about local variables being shadowed by compatible local variables in an inner scope. Of course, this is perfectly valid in C, but we have had bugs in the past as a result of developers failing to notice this. af7d270dd is a recent example. Here we do a cleanup of warnings we receive from -Wshadow=compatible-local for code which is new to PostgreSQL 15. We've yet to have the discussion about if we actually ever want to run that as a standard compilation flag. We'll need to at least get the number of warnings down to something easier to manage before we can realistically consider if we want this or not. This commit is the first step towards reducing the warnings. The changes being made here are all fairly trivial. Because of that, and the fact that v15 is still in beta, this is being back-patched into 15. It seems more risky not to do this as the risk of future bugs is increased by the additional conflicts that this commit could cause for any future bug fixes touching the same areas as this commit. Author: Justin Pryzby Discussion: https://postgr.es/m/20220817145434.GC26426%40telsasoft.com Backpatch-through: 15
2022-08-17Avoid using list_length() to test for empty list.Tom Lane
The standard way to check for list emptiness is to compare the List pointer to NIL; our list code goes out of its way to ensure that that is the only representation of an empty list. (An acceptable alternative is a plain boolean test for non-null pointer, but explicit mention of NIL is usually preferable.) Various places didn't get that memo and expressed the condition with list_length(), which might not be so bad except that there were such a variety of ways to check it exactly: equal to zero, less than or equal to zero, less than one, yadda yadda. In the name of code readability, let's standardize all those spellings as "list == NIL" or "list != NIL". (There's probably some microscopic efficiency gain too, though few of these look to be at all performance-critical.) A very small number of cases were left as-is because they seemed more consistent with other adjacent list_length tests that way. Peter Smith, with bikeshedding from a number of us Discussion: https://postgr.es/m/CAHut+PtQYe+ENX5KrONMfugf0q6NHg4hR5dAhqEXEc2eefFeig@mail.gmail.com
2022-07-27Refactor code in charge of grabbing the relations of a subscriptionMichael Paquier
GetSubscriptionRelations() and GetSubscriptionNotReadyRelations() share mostly the same code, which scans pg_subscription_rel and fetches all the relations of a given subscription. The only difference is that the second routine looks for all the relations not in a ready state. This commit refactors the code to use a single routine, shaving a bit of code. Author: Vignesh C Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Michael Paquier, Peter Smith Discussion: https://postgr.es/m/CALDaNm0eW-9g4G_EzHebnFT5zZoasWCS_EzZQ5BgnLZny9S=pg@mail.gmail.com
2022-06-02Prohibit combining publications with different column lists.Amit Kapila
Currently, we simply combine the column lists when publishing tables on multiple publications and that can sometimes lead to unexpected behavior. Say, if a column is published in any row-filtered publication, then the values for that column are sent to the subscriber even for rows that don't match the row filter, as long as the row matches the row filter for any other publication, even if that other publication doesn't include the column. The main purpose of introducing a column list is to have statically different shapes on publisher and subscriber or hide sensitive column data. In both cases, it doesn't seem to make sense to combine column lists. So, we disallow the cases where the column list is different for the same table when combining publications. It can be later extended to combine the column lists for selective cases where required. Reported-by: Alvaro Herrera Author: Hou Zhijie Reviewed-by: Amit Kapila Discussion: https://postgr.es/m/202204251548.mudq7jbqnh7r@alvherre.pgsql
2022-05-19Extend pg_publication_tables to display column list and row filter.Amit Kapila
Commit 923def9a53 and 52e4f0cd47 allowed to specify column lists and row filters for publication tables. This commit extends the pg_publication_tables view and pg_get_publication_tables function to display that information. This information will be useful to users and we also need this for the later commit that prohibits combining multiple publications with different column lists for the same table. Author: Hou Zhijie Reviewed By: Amit Kapila, Alvaro Herrera, Shi Yu, Takamichi Osumi Discussion: https://postgr.es/m/202204251548.mudq7jbqnh7r@alvherre.pgsql