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* Fix catalog lookup with the wrong snapshot during logical decoding.Amit Kapila2022-08-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, we relied on HEAP2_NEW_CID records and XACT_INVALIDATION records to know if the transaction has modified the catalog, and that information is not serialized to snapshot. Therefore, after the restart, if the logical decoding decodes only the commit record of the transaction that has actually modified a catalog, we will miss adding its XID to the snapshot. Thus, we will end up looking at catalogs with the wrong snapshot. To fix this problem, this change adds the list of transaction IDs and sub-transaction IDs, that have modified catalogs and are running during snapshot serialization, to the serialized snapshot. After restart or otherwise, when we restore from such a serialized snapshot, the corresponding list is restored in memory. Now, when decoding a COMMIT record, we check both the list and the ReorderBuffer to see if the transaction has modified catalogs. Since this adds additional information to the serialized snapshot, we cannot backpatch it. For back branches, we took another approach. We remember the last-running-xacts list of the decoded RUNNING_XACTS record after restoring the previously serialized snapshot. Then, we mark the transaction as containing catalog changes if it's in the list of initial running transactions and its commit record has XACT_XINFO_HAS_INVALS. This doesn't require any file format changes but the transaction will end up being added to the snapshot even if it has only relcache invalidations. But that won't be a problem since we use snapshot built during decoding only to read system catalogs. This commit bumps SNAPBUILD_VERSION because of a change in SnapBuild. Reported-by: Mike Oh Author: Masahiko Sawada Reviewed-by: Amit Kapila, Shi yu, Takamichi Osumi, Kyotaro Horiguchi, Bertrand Drouvot, Ahsan Hadi Backpatch-through: 10 Discussion: https://postgr.es/m/81D0D8B0-E7C4-4999-B616-1E5004DBDCD2%40amazon.com
* Change internal RelFileNode references to RelFileNumber or RelFileLocator.Robert Haas2022-07-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
* Pre-beta mechanical code beautification.Tom Lane2022-05-12
| | | | | Run pgindent, pgperltidy, and reformat-dat-files. I manually fixed a couple of comments that pgindent uglified.
* Revert "Logical decoding of sequences"Tomas Vondra2022-04-07
| | | | | | | | | | | | | | | | | | | | | This reverts a sequence of commits, implementing features related to logical decoding and replication of sequences: - 0da92dc530c9251735fc70b20cd004d9630a1266 - 80901b32913ffa59bf157a4d88284b2b3a7511d9 - b779d7d8fdae088d70da5ed9fcd8205035676df3 - d5ed9da41d96988d905b49bebb273a9b2d6e2915 - a180c2b34de0989269fdb819bff241a249bf5380 - 75b1521dae1ff1fde17fda2e30e591f2e5d64b6a - 2d2232933b02d9396113662e44dca5f120d6830e - 002c9dd97a0c874fd1693a570383e2dd38cd40d5 - 05843b1aa49df2ecc9b97c693b755bd1b6f856a9 The implementation has issues, mostly due to combining transactional and non-transactional behavior of sequences. It's not clear how this could be fixed, but it'll require reworking significant part of the patch. Discussion: https://postgr.es/m/95345a19-d508-63d1-860a-f5c2f41e8d40@enterprisedb.com
* Custom WAL Resource Managers.Jeff Davis2022-04-06
| | | | | | | | | | | | | Allow extensions to specify a new custom resource manager (rmgr), which allows specialized WAL. This is meant to be used by a Table Access Method or Index Access Method. Prior to this commit, only Generic WAL was available, which offers support for recovery and physical replication but not logical replication. Reviewed-by: Julien Rouhaud, Bharath Rupireddy, Andres Freund Discussion: https://postgr.es/m/ed1fb2e22d15d3563ae0eb610f7b61bb15999c0a.camel%40j-davis.com
* Add circular WAL decoding buffer, take II.Thomas Munro2022-03-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Teach xlogreader.c to decode the WAL into a circular buffer. This will support optimizations based on looking ahead, to follow in a later commit. * XLogReadRecord() works as before, decoding records one by one, and allowing them to be examined via the traditional XLogRecGetXXX() macros and certain traditional members like xlogreader->ReadRecPtr. * An alternative new interface XLogReadAhead()/XLogNextRecord() is added that returns pointers to DecodedXLogRecord objects so that it's now possible to look ahead in the WAL stream while replaying. * In order to be able to use the new interface effectively while streaming data, support is added for the page_read() callback to respond to a new nonblocking mode with XLREAD_WOULDBLOCK instead of waiting for more data to arrive. No direct user of the new interface is included in this commit, though XLogReadRecord() uses it internally. Existing code doesn't need to change, except in a few places where it was accessing reader internals directly and now needs to go through accessor macros. Reviewed-by: Julien Rouhaud <rjuju123@gmail.com> Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com> Reviewed-by: Andres Freund <andres@anarazel.de> (earlier versions) Discussion: https://postgr.es/m/CA+hUKGJ4VJN8ttxScUFM8dOKX0BrBiboo5uz1cq=AovOddfHpA@mail.gmail.com
* Call ReorderBufferProcessXid from sequence_decodeTomas Vondra2022-03-07
| | | | | | | | | Commit 0da92dc530c added sequence_decode() implementing logical decoding of sequences, but it failed to call ReorderBufferProcessXid() as it should. So add the missing call. Reported-by: Amit Kapila Discussion: https://postgr.es/m/CAA4eK1KGn6cQqJEsubOOENwQOANsExiV2sKL52r4U10J8NJEMQ%40mail.gmail.com
* Logical decoding of sequencesTomas Vondra2022-02-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This extends the logical decoding to also decode sequence increments. We differentiate between sequences created in the current (in-progress) transaction, and sequences created earlier. This mixed behavior is necessary because while sequences are not transactional (increments are not subject to ROLLBACK), relfilenode changes are. So we do this: * Changes for sequences created in the same top-level transaction are treated as transactional, i.e. just like any other change from that transaction, and discarded in case of a rollback. * Changes for sequences created earlier are applied immediately, as if performed outside any transaction. This applies also after ALTER SEQUENCE, which may create a new relfilenode. Moreover, if we ever get support for DDL replication, the sequence won't exist until the transaction gets applied. Sequences created in the current transaction are tracked in a simple hash table, identified by a relfilenode. That means a sequence may already exist, but if a transaction does ALTER SEQUENCE then the increments for the new relfilenode will be treated as transactional. For each relfilenode we track the XID of (sub)transaction that created it, which is needed for cleanup at transaction end. We don't need to check the XID to decide if an increment is transactional - if we find a match in the hash table, it has to be the same transaction. This requires two minor changes to WAL-logging. Firstly, we need to ensure the sequence record has a valid XID - until now the the increment might have XID 0 if it was the first change in a subxact. But the sequence might have been created in the same top-level transaction. So we ensure the XID is assigned when WAL-logging increments. The other change is addition of "created" flag, marking increments for newly created relfilenodes. This makes it easier to maintain the hash table of sequences that need transactional handling. Note: This is needed because of subxacts. A XID 0 might still have the sequence created in a different subxact of the same top-level xact. This does not include any changes to test_decoding and/or the built-in replication - those will be committed in separate patches. A patch adding decoding of sequences was originally submitted by Cary Huang. This commit reworks various important aspects (e.g. the WAL logging and transactional/non-transactional handling). However, the original patch and reviews were very useful. 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
* Clean up recent Coverity complaints.Tom Lane2022-01-23
| | | | | | | | | | | | | | Commit 5c649fe15 introduced a memory leak into pg_basebackup's parse_compress_options. (I simplified nearby code while at it.) Commit 9a974cbcb introduced a memory leak into pg_dump's binary_upgrade_set_pg_class_oids. Coverity also complained about a call of SnapBuildProcessChange that ignored the result, unlike every other call of that function. This is evidently intentional, so add a (void) cast to indicate that. (It's also old, dating to b89e15105; I suppose the reason it showed up now is 7a5f6b474's recent rearrangement of nearby code.)
* Make logical decoding a part of the rmgr.Jeff Davis2022-01-19
| | | | | | | | | | | Add a new rmgr method, rm_decode, and use that rather than a switch statement. In preparation for rmgr extensibility. Reviewed-by: Julien Rouhaud Discussion: https://postgr.es/m/ed1fb2e22d15d3563ae0eb610f7b61bb15999c0a.camel%40j-davis.com Discussion: https://postgr.es/m/20220118095332.6xtlcjoyxobv6cbk@jrouhaud
* Update copyright for 2022Bruce Momjian2022-01-07
| | | | Backpatch-through: 10
* Fix origin timestamp during decoding of ROLLBACK PREPARED operation.Amit Kapila2021-12-08
| | | | | | | | | | This happens because we were passing incorrect arguments to ReorderBufferFinishPrepared(). Author: Masahiko Sawada Reviewed-by: Vignesh C Backpatch-through: 14 Discussion: https://postgr.es/m/CAD21AoBqhUqgDZUhUVnnwKRubPDNJ6m6fJDPgok3E5cWJLL+pA@mail.gmail.com
* Handle XLOG_OVERWRITE_CONTRECORD in DecodeXLogOpAlvaro Herrera2021-11-01
| | | | | | | | | Failing to do so results in inability of logical decoding to process the WAL stream. Handle it by doing nothing. Backpatch all the way back. Reported-by: Petr Jelínek <petr.jelinek@enterprisedb.com>
* Add support for prepared transactions to built-in logical replication.Amit Kapila2021-07-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To add support for streaming transactions at prepare time into the built-in logical replication, we need to do the following things: * Modify the output plugin (pgoutput) to implement the new two-phase API callbacks, by leveraging the extended replication protocol. * Modify the replication apply worker, to properly handle two-phase transactions by replaying them on prepare. * Add a new SUBSCRIPTION option "two_phase" to allow users to enable two-phase transactions. We enable the two_phase once the initial data sync is over. We however must explicitly disable replication of two-phase transactions during replication slot creation, even if the plugin supports it. We don't need to replicate the changes accumulated during this phase, and moreover, we don't have a replication connection open so we don't know where to send the data anyway. The streaming option is not allowed with this new two_phase option. This can be done as a separate patch. We don't allow to toggle two_phase option of a subscription because it can lead to an inconsistent replica. For the same reason, we don't allow to refresh the publication once the two_phase is enabled for a subscription unless copy_data option is false. Author: Peter Smith, Ajin Cherian and Amit Kapila based on previous work by Nikhil Sontakke and Stas Kelvich Reviewed-by: Amit Kapila, Sawada Masahiko, Vignesh C, Dilip Kumar, Takamichi Osumi, Greg Nancarrow Tested-By: Haiying Tang Discussion: https://postgr.es/m/02DA5F5E-CECE-4D9C-8B4B-418077E2C010@postgrespro.ru Discussion: https://postgr.es/m/CAA4eK1+opiV4aFTmWWUF9h_32=HfPOW9vZASHarT0UA5oBrtGw@mail.gmail.com
* Fix decoding of speculative aborts.Amit Kapila2021-06-15
| | | | | | | | | | | | | | | | | | | | | | During decoding for speculative inserts, we were relying for cleaning toast hash on confirmation records or next change records. But that could lead to multiple problems (a) memory leak if there is neither a confirmation record nor any other record after toast insertion for a speculative insert in the transaction, (b) error and assertion failures if the next operation is not an insert/update on the same table. The fix is to start queuing spec abort change and clean up toast hash and change record during its processing. Currently, we are queuing the spec aborts for both toast and main table even though we perform cleanup while processing the main table's spec abort record. Later, if we have a way to distinguish between the spec abort record of toast and the main table, we can avoid queuing the change for spec aborts of toast tables. Reported-by: Ashutosh Bapat Author: Dilip Kumar Reviewed-by: Amit Kapila Backpatch-through: 9.6, where it was introduced Discussion: https://postgr.es/m/CAExHW5sPKF-Oovx_qZe4p5oM6Dvof7_P+XgsNAViug15Fm99jA@mail.gmail.com
* Revert recovery prefetching feature.Thomas Munro2021-05-10
| | | | | | | | | | | | | | | | | | This set of commits has some bugs with known fixes, but at this late stage in the release cycle it seems best to revert and resubmit next time, along with some new automated test coverage for this whole area. Commits reverted: dc88460c: Doc: Review for "Optionally prefetch referenced data in recovery." 1d257577: Optionally prefetch referenced data in recovery. f003d9f8: Add circular WAL decoding buffer. 323cbe7c: Remove read_page callback from XLogReader. Remove the new GUC group WAL_RECOVERY recently added by a55a9847, as the corresponding section of config.sgml is now reverted. Discussion: https://postgr.es/m/CAOuzzgrn7iKnFRsB4MHp3UisEQAGgZMbk_ViTN4HV4-Ksq8zCg%40mail.gmail.com
* Update replication statistics after every stream/spill.Amit Kapila2021-05-06
| | | | | | | | | | | | | | Currently, replication slot statistics are updated at prepare, commit, and rollback. Now, if the transaction is interrupted the stats might not get updated. Fixed this by updating replication statistics after every stream/spill. In passing update the docs to change the description of some of the slot stats. Author: Vignesh C, Sawada Masahiko Reviewed-by: Amit Kapila Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
* Add circular WAL decoding buffer.Thomas Munro2021-04-08
| | | | | | | | | | | | | | | | | | | | | | | | | Teach xlogreader.c to decode its output into a circular buffer, to support optimizations based on looking ahead. * XLogReadRecord() works as before, consuming records one by one, and allowing them to be examined via the traditional XLogRecGetXXX() macros. * An alternative new interface XLogNextRecord() is added that returns pointers to DecodedXLogRecord structs that can be examined directly. * XLogReadAhead() provides a second cursor that lets you see further ahead, as long as data is available and there is enough space in the decoding buffer. This returns DecodedXLogRecord pointers to the caller, but also adds them to a queue of records that will later be consumed by XLogNextRecord()/XLogReadRecord(). The buffer's size is controlled with wal_decode_buffer_size. The buffer could potentially be placed into shared memory, for future projects. Large records that don't fit in the circular buffer are called "oversized" and allocated separately with palloc(). Discussion: https://postgr.es/m/CA+hUKGJ4VJN8ttxScUFM8dOKX0BrBiboo5uz1cq=AovOddfHpA@mail.gmail.com
* Remove tupgone special case from vacuumlazy.c.Peter Geoghegan2021-04-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Retry the call to heap_prune_page() in rare cases where there is disagreement between the heap_prune_page() call and the call to HeapTupleSatisfiesVacuum() that immediately follows. Disagreement is possible when a concurrently-aborted transaction makes a tuple DEAD during the tiny window between each step. This was the only case where a tuple considered DEAD by VACUUM still had storage following pruning. VACUUM's definition of dead tuples is now uniformly simple and unambiguous: dead tuples from each page are always LP_DEAD line pointers that were encountered just after we performed pruning (and just before we considered freezing remaining items with tuple storage). Eliminating the tupgone=true special case enables INDEX_CLEANUP=off style skipping of index vacuuming that takes place based on flexible, dynamic criteria. The INDEX_CLEANUP=off case had to know about skipping indexes up-front before now, due to a subtle interaction with the special case (see commit dd695979) -- this was a special case unto itself. Now there are no special cases. And so now it won't matter when or how we decide to skip index vacuuming: it won't affect how pruning behaves, and it won't be affected by any of the implementation details of pruning or freezing. Also remove XLOG_HEAP2_CLEANUP_INFO records. These are no longer necessary because we now rely entirely on heap pruning taking care of recovery conflicts. There is no longer any need to generate recovery conflicts for DEAD tuples that pruning just missed. This also means that heap vacuuming now uses exactly the same strategy for recovery conflicts as index vacuuming always has: REDO routines never need to process a latestRemovedXid from the WAL record, since earlier REDO of the WAL record from pruning is sufficient in all cases. The generic XLOG_HEAP2_CLEAN record type is now split into two new record types to reflect this new division (these are called XLOG_HEAP2_PRUNE and XLOG_HEAP2_VACUUM). Also stop acquiring a super-exclusive lock for heap pages when they're vacuumed during VACUUM's second heap pass. A regular exclusive lock is enough. This is correct because heap page vacuuming is now strictly a matter of setting the LP_DEAD line pointers to LP_UNUSED. No other backend can have a pointer to a tuple located in a pinned buffer that can be invalidated by a concurrent heap page vacuum operation. Heap vacuuming can now be thought of as conceptually similar to index vacuuming and conceptually dissimilar to heap pruning. Heap pruning now has sole responsibility for anything involving the logical contents of the database (e.g., managing transaction status information, recovery conflicts, considering what to do with HOT chains). Index vacuuming and heap vacuuming are now only concerned with recycling garbage items from physical data structures that back the logical database. Bump XLOG_PAGE_MAGIC due to pruning and heap page vacuum WAL record changes. Credit for the idea of retrying pruning a page to avoid the tupgone case goes to Andres Freund. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Andres Freund <andres@anarazel.de> Reviewed-By: Masahiko Sawada <sawada.mshk@gmail.com> Discussion: https://postgr.es/m/CAH2-WznneCXTzuFmcwx_EyRQgfsfJAAsu+CsqRFmFXCAar=nJw@mail.gmail.com
* Add a xid argument to the filter_prepare callback for output plugins.Amit Kapila2021-03-30
| | | | | | | | | | | | Along with gid, this provides a different way to identify the transaction. The users that use xid in some way to prepare the transactions can use it to filter prepare transactions. The later commands COMMIT PREPARED or ROLLBACK PREPARED carries both identifiers, providing an output plugin the choice of what to use. Author: Markus Wanner Reviewed-by: Vignesh C, Amit Kapila Discussion: https://postgr.es/m/ee280000-7355-c4dc-e47b-2436e7be959c@enterprisedb.com
* Avoid repeated decoding of prepared transactions after a restart.Amit Kapila2021-03-01
| | | | | | | | | | | | | | | | | | | | In commit a271a1b50e, we allowed decoding at prepare time and the prepare was decoded again if there is a restart after decoding it. It was done that way because we can't distinguish between the cases where we have not decoded the prepare because it was prior to consistent snapshot or we have decoded it earlier but restarted. To distinguish between these two cases, we have introduced an initial_consistent_point at the slot level which is an LSN at which we found a consistent point at the time of slot creation. This is also the point where we have exported a snapshot for the initial copy. So, prepare transaction prior to this point are sent along with commit prepared. This commit bumps SNAPBUILD_VERSION because of change in SnapBuild. It will break existing slots which is fine in a major release. Author: Ajin Cherian, based on idea by Andres Freund Reviewed-by: Amit Kapila and Vignesh C Discussion: https://postgr.es/m/d0f60d60-133d-bf8d-bd70-47784d8fabf3@enterprisedb.com
* Update the docs and comments for decoding of prepared xacts.Amit Kapila2021-03-01
| | | | | | | | | | | | Commit a271a1b50e introduced decoding at prepare time in ReorderBuffer. This can lead to deadlock for out-of-core logical replication solutions that uses this feature to build distributed 2PC in case such transactions lock [user] catalog tables exclusively. They need to inform users to not have locks on catalog tables (via explicit LOCK command) in such transactions. Reported-by: Andres Freund Discussion: https://postgr.es/m/20210222222847.tpnb6eg3yiykzpky@alap3.anarazel.de
* Fix typos in decode.c and logical.c.Amit Kapila2021-01-06
| | | | | Per report by Ajin Cherian in email: https://postgr.es/m/CAFPTHDYnRKDvzgDxoMn_CKqXA-D0MtrbyJvfvjBsO4G=UHDXkg@mail.gmail.com
* Allow decoding at prepare time in ReorderBuffer.Amit Kapila2021-01-04
| | | | | | | | | | | | | | | | | | | | | | | 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.ru https://postgr.es/m/CAMGcDxeqEpWj3fTXwqhSwBdXd2RS9jzwWscO-XbeCfso6ts3+Q@mail.gmail.com
* Update copyright for 2021Bruce Momjian2021-01-02
| | | | Backpatch-through: 9.5
* Track statistics for spilling of changes from ReorderBuffer.Amit Kapila2020-10-08
| | | | | | | | | | | | | | | This adds the statistics about transactions spilled to disk from ReorderBuffer. Users can query the pg_stat_replication_slots view to check these stats and call pg_stat_reset_replication_slot to reset the stats of a particular slot. Users can pass NULL in pg_stat_reset_replication_slot to reset stats of all the slots. This commit extends the statistics collector to track this information about slots. Author: Sawada Masahiko and Amit Kapila Reviewed-by: Amit Kapila and Dilip Kumar Discussion: https://postgr.es/m/CA+fd4k5_pPAYRTDrO2PbtTOe0eHQpBvuqmCr8ic39uTNmR49Eg@mail.gmail.com
* Implement streaming mode in ReorderBuffer.Amit Kapila2020-08-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* WAL Log invalidations at command end with wal_level=logical.Amit Kapila2020-07-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When wal_level=logical, write invalidations at command end into WAL so that decoding can use this information. This patch is required to allow the streaming of in-progress transactions in logical decoding.  The actual work to allow streaming will be committed as a separate patch. We still add the invalidations to the cache and write them to WAL at commit time in RecordTransactionCommit(). This uses the existing XLOG_INVALIDATIONS xlog record type, from the RM_STANDBY_ID resource manager (see LogStandbyInvalidations for details). So existing code relying on those invalidations (e.g. redo) does not need to be changed. The invalidations written at command end uses a new xlog record type XLOG_XACT_INVALIDATIONS, from RM_XACT_ID resource manager. See LogLogicalInvalidations for details. These new xlog records are ignored by existing redo procedures, which still rely on the invalidations written to commit records. The invalidations are decoded and accumulated in top-transaction, and then executed during replay.  This obviates the need to decode the invalidations as part of a commit record. Bump XLOG_PAGE_MAGIC, since this introduces XLOG_XACT_INVALIDATIONS. Author: Dilip Kumar, Tomas Vondra, Amit Kapila Reviewed-by: Amit Kapila Tested-by: Neha Sharma and Mahendra Singh Thalor Discussion: https://postgr.es/m/688b0b7f-2f6c-d827-c27b-216a8e3ea700@2ndquadrant.com
* Immediately WAL-log subtransaction and top-level XID association.Amit Kapila2020-07-20
| | | | | | | | | | | | | | | | | | | | The logical decoding infrastructure needs to know which top-level transaction the subxact belongs to, in order to decode all the changes. Until now that might be delayed until commit, due to the caching (GPROC_MAX_CACHED_SUBXIDS), preventing features requiring incremental decoding. So we also write the assignment info into WAL immediately, as part of the next WAL record (to minimize overhead) only when wal_level=logical. We can not remove the existing XLOG_XACT_ASSIGNMENT WAL as that is required for avoiding overflow in the hot standby snapshot. Bump XLOG_PAGE_MAGIC, since this introduces XLR_BLOCK_ID_TOPLEVEL_XID. Author: Tomas Vondra, Dilip Kumar, Amit Kapila Reviewed-by: Amit Kapila Tested-by: Neha Sharma and Mahendra Singh Thalor Discussion: https://postgr.es/m/688b0b7f-2f6c-d827-c27b-216a8e3ea700@2ndquadrant.com
* Represent command completion tags as structsAlvaro Herrera2020-03-02
| | | | | | | | | | | | | | | | | | | | | | The backend was using strings to represent command tags and doing string comparisons in multiple places, but that's slow and unhelpful. Create a new command list with a supporting structure to use instead; this is stored in a tag-list-file that can be tailored to specific purposes with a caller-definable C macro, similar to what we do for WAL resource managers. The first first such uses are a new CommandTag enum and a CommandTagBehavior struct. Replace numerous occurrences of char *completionTag with a QueryCompletion struct so that the code no longer stores information about completed queries in a cstring. Only at the last moment, in EndCommand(), does this get converted to a string. EventTriggerCacheItem no longer holds an array of palloc’d tag strings in sorted order, but rather just a Bitmapset over the CommandTags. Author: Mark Dilger, with unsolicited help from Álvaro Herrera Reviewed-by: John Naylor, Tom Lane Discussion: https://postgr.es/m/981A9DB4-3F0C-4DA5-88AD-CB9CFF4D6CAD@enterprisedb.com
* Handle logical decoding in multi-insert for catalog tuplesMichael Paquier2020-03-02
| | | | | | | | | The code path for multi-insert decoding is not stressed yet for catalogs (a future patch may introduce this capability), so no back-patch is needed. Author: Daniel Gustafsson Discussion: https://postgr.es/m/9690D72F-5C4F-4016-9572-6D16684E1D87@yesql.se
* Update copyrights for 2020Bruce Momjian2020-01-01
| | | | Backpatch-through: update all files in master, backpatch legal files through 9.4
* Make the order of the header file includes consistent in backend modules.Amit Kapila2019-11-12
| | | | | | | | | | | Similar to commits 7e735035f2 and dddf4cdc33, this commit makes the order of header file inclusion consistent for backend modules. In the passing, removed a couple of duplicate inclusions. Author: Vignesh C Reviewed-by: Kuntal Ghosh and Amit Kapila Discussion: https://postgr.es/m/CALDaNm2Sznv8RR6Ex-iJO6xAdsxgWhCoETkaYX=+9DW3q0QCfA@mail.gmail.com
* logical decoding: process ASSIGNMENT during snapshot buildAlvaro Herrera2019-09-13
| | | | | | | | | | | | | Most WAL records are ignored in early SnapBuild snapshot build phases. But it's critical to process some of them, so that later messages have the correct transaction state after the snapshot is completely built; in particular, XLOG_XACT_ASSIGNMENT messages are critical in order for sub-transactions to be correctly assigned to their parent transactions, or at least one assert misbehaves, as reported by Ildar Musin. Diagnosed-by: Masahiko Sawada Author: Masahiko Sawada Discussion: https://postgr.es/m/CAONYFtOv+Er1p3WAuwUsy1zsCFrSYvpHLhapC_fMD-zNaRWxYg@mail.gmail.com
* Adjust tuple data lookup logic in multi-insert logical decodingMichael Paquier2019-08-07
| | | | | | | | | | | | | | | | | | | | As of now, logical decoding of a multi-insert has been scanning all xl_multi_insert_tuple entries only if XLH_INSERT_CONTAINS_NEW_TUPLE was getting set in the record. This is not an issue on HEAD as multi-insert records are not used for system catalogs, but the logical decoding logic includes all the code necessary to handle that properly, except that the code missed to iterate correctly over all xl_multi_insert_tuple entries when the flag is not set. Hence, when trying to use multi-insert for system catalogs, an assertion would be triggered. An upcoming patch is going to make use of multi-insert for system catalogs, and this fixes the logic to make sure that all entries are scanned correctly without softening the existing assertions. Reported-by: Daniel Gustafsson Author: Michael Paquier Reviewed-by: Daniel Gustafsson Discussion: https://postgr.es/m/CBFFD532-C033-49EB-9A5A-F67EAEE9EB0B@yesql.se
* Phase 2 pgindent run for v12.Tom Lane2019-05-22
| | | | | | | | | Switch to 2.1 version of pg_bsd_indent. This formats multiline function declarations "correctly", that is with additional lines of parameter declarations indented to match where the first line's left parenthesis is. Discussion: https://postgr.es/m/CAEepm=0P3FeTXRcU5B2W3jv3PgRVZ-kGUXLGfd42FFhUROO3ug@mail.gmail.com
* Update copyright for 2019Bruce Momjian2019-01-02
| | | | Backpatch-through: certain files through 9.4
* Do not decode TOAST data for table rewritesTomas Vondra2018-11-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During table rewrites (VACUUM FULL and CLUSTER), the main heap is logged using XLOG / FPI records, and thus (correctly) ignored in decoding. But the associated TOAST table is WAL-logged as plain INSERT records, and so was logically decoded and passed to reorder buffer. That has severe consequences with TOAST tables of non-trivial size. Firstly, reorder buffer has to keep all those changes, possibly spilling them to a file, incurring I/O costs and disk space. Secondly, ReoderBufferCommit() was stashing all those TOAST chunks into a hash table, which got discarded only after processing the row from the main heap. But as the main heap is not decoded for rewrites, this never happened, so all the TOAST data accumulated in memory, resulting either in excessive memory consumption or OOM. The fix is simple, as commit e9edc1ba already introduced infrastructure (namely HEAP_INSERT_NO_LOGICAL flag) to skip logical decoding of TOAST tables, but it only applied it to system tables. So simply use it for all TOAST data in raw_heap_insert(). That would however solve only the memory consumption issue - the TOAST changes would still be decoded and added to the reorder buffer, and spilled to disk (although without TOAST tuple data, so much smaller). But we can solve that by tweaking DecodeInsert() to just ignore such INSERT records altogether, using XLH_INSERT_CONTAINS_NEW_TUPLE flag, instead of skipping them later in ReorderBufferCommit(). Review: Masahiko Sawada Discussion: https://www.postgresql.org/message-id/flat/1a17c643-e9af-3dba-486b-fbe31bc1823a%402ndquadrant.com Backpatch: 9.4-, where logical decoding was introduced
* Fix memory leak in TRUNCATE decodingTomas Vondra2018-09-03
| | | | | | | | | | | | | | | | | | | | | | | | When decoding a TRUNCATE record, the relids array was being allocated in the main ReorderBuffer memory context, but not released with the change resulting in a memory leak. The array was also ignored when serializing/deserializing the change, assuming all the information is stored in the change itself. So when spilling the change to disk, we've only we have serialized only the pointer to the relids array. Thanks to never releasing the array, the pointer however remained valid even after loading the change back to memory, preventing an actual crash. This fixes both the memory leak and (de)serialization. The relids array is still allocated in the main ReorderBuffer memory context (none of the existing ones seems like a good match, and adding an extra context seems like an overkill). The allocation is wrapped in a new ReorderBuffer API functions, to keep the details within reorderbuffer.c, just like the other ReorderBufferGet methods do. Author: Tomas Vondra Discussion: https://www.postgresql.org/message-id/flat/66175a41-9342-2845-652f-1bd4c3ee50aa%402ndquadrant.com Backpatch: 11, where decoding of TRUNCATE was introduced
* Revert "Allow on-line enabling and disabling of data checksums"Magnus Hagander2018-04-09
| | | | | | | | This reverts the backend sides of commit 1fde38beaa0c3e66c340efc7cc0dc272d6254bb0. I have, at least for now, left the pg_verify_checksums tool in place, as this tool can be very valuable without the rest of the patch as well, and since it's a read-only tool that only runs when the cluster is down it should be a lot safer.
* Logical decoding of TRUNCATEPeter Eisentraut2018-04-07
| | | | | | | | | | | | | | Add a new WAL record type for TRUNCATE, which is only used when wal_level >= logical. (For physical replication, TRUNCATE is already replicated via SMGR records.) Add new callback for logical decoding output plugins to receive TRUNCATE actions. Author: Simon Riggs <simon@2ndquadrant.com> Author: Marco Nenciarini <marco.nenciarini@2ndquadrant.it> Author: Peter Eisentraut <peter.eisentraut@2ndquadrant.com> Reviewed-by: Petr Jelinek <petr.jelinek@2ndquadrant.com> Reviewed-by: Andres Freund <andres@anarazel.de> Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
* Allow on-line enabling and disabling of data checksumsMagnus Hagander2018-04-05
| | | | | | | | | | | | | | | | | | | This makes it possible to turn checksums on in a live cluster, without the previous need for dump/reload or logical replication (and to turn it off). Enabling checkusm starts a background process in the form of a launcher/worker combination that goes through the entire database and recalculates checksums on each and every page. Only when all pages have been checksummed are they fully enabled in the cluster. Any failure of the process will revert to checksums off and the process has to be started. This adds a new WAL record that indicates the state of checksums, so the process works across replicated clusters. Authors: Magnus Hagander and Daniel Gustafsson Review: Tomas Vondra, Michael Banck, Heikki Linnakangas, Andrey Borodin
* Ability to advance replication slotsSimon Riggs2018-01-17
| | | | | | | | | | | | | | | Ability to advance both physical and logical replication slots using a new user function pg_replication_slot_advance(). For logical advance that means records are consumed as fast as possible and changes are not given to output plugin for sending. Makes 2nd phase (after we reached SNAPBUILD_FULL_SNAPSHOT) of replication slot creation faster, especially when there are big transactions as the reorder buffer does not have to deal with data changes and does not have to spill to disk. Author: Petr Jelinek Reviewed-by: Simon Riggs
* Update copyright for 2018Bruce Momjian2018-01-02
| | | | Backpatch-through: certain files through 9.3
* Phase 3 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | Don't move parenthesized lines to the left, even if that means they flow past the right margin. By default, BSD indent lines up statement continuation lines that are within parentheses so that they start just to the right of the preceding left parenthesis. However, traditionally, if that resulted in the continuation line extending to the right of the desired right margin, then indent would push it left just far enough to not overrun the margin, if it could do so without making the continuation line start to the left of the current statement indent. That makes for a weird mix of indentations unless one has been completely rigid about never violating the 80-column limit. This behavior has been pretty universally panned by Postgres developers. Hence, disable it with indent's new -lpl switch, so that parenthesized lines are always lined up with the preceding left paren. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Fix race condition leading to hanging logical slot creation.Andres Freund2017-05-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The snapshot assembly during the creation of logical slots relied waiting for transactions in xl_running_xacts to end, by checking for their commit/abort records. Unfortunately, despite locking, it is possible to see an xl_running_xact record listing transactions as ready, that have already WAL-logged an commit/abort record, as the locking just prevents the ProcArray to be adjusted, and the commit record has to be logged first. That lead to either delayed or hanging snapshot creation, because snapbuild.c would wait "forever" to see commit/abort records for some transactions. That hang resolved only if a xl_running_xacts record without any running transactions happened to be logged, far from certain on a busy server. It's impractical to prevent that via more heavyweight locking, the likelihood of deadlocks and significantly increased contention would be too big. Instead change the initial snapshot creation to be solely based on tracking the oldest running transaction via xl_running_xacts->oldestRunningXid - that actually ends up significantly simplifying the code. That has two disadvantages: 1) Because we cannot fully "trust" the contents of xl_running_xacts, we cannot use it to build the initial snapshot. Instead we have to wait twice for all running transactions to finish. 2) Previously a slot, unless the race occurred, could be created when the all transaction perceived as running based on commit/abort records, now we have to wait for the next xl_running_xacts record. To address that, trigger logging new xl_running_xacts record from within snapbuild.c exactly when necessary. Unfortunately snabuild.c's SnapBuild is stored on disk, one of the stupider ideas of a certain Mr Freund, so we can't change it in a minor release. As this is going to be backpatched, we have to hack around a bit to keep on-disk compatibility. A later commit will rejigger that on master. Author: Andres Freund, based on a quite different patch from Petr Jelinek Analyzed-By: Petr Jelinek Reviewed-By: Petr Jelinek Discussion: https://postgr.es/m/f37e975c-908f-858e-707f-058d3b1eb214@2ndquadrant.com Backpatch: 9.4-, where logical decoding has been introduced
* Update copyright via script for 2017Bruce Momjian2017-01-03
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* pgindent run for 9.6Robert Haas2016-06-09
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* Emit invalidations to standby for transactions without xid.Andres Freund2016-04-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | So far, when a transaction with pending invalidations, but without an assigned xid, committed, we simply ignored those invalidation messages. That's problematic, because those are actually sent for a reason. Known symptoms of this include that existing sessions on a hot-standby replica sometimes fail to notice new concurrently built indexes and visibility map updates. The solution is to WAL log such invalidations in transactions without an xid. We considered to alternatively force-assign an xid, but that'd be problematic for vacuum, which might be run in systems with few xids. Important: This adds a new WAL record, but as the patch has to be back-patched, we can't bump the WAL page magic. This means that standbys have to be updated before primaries; otherwise "PANIC: standby_redo: unknown op code 32" errors can be encountered. XXX: Reported-By: Васильев Дмитрий, Masahiko Sawada Discussion: CAB-SwXY6oH=9twBkXJtgR4UC1NqT-vpYAtxCseME62ADwyK5OA@mail.gmail.com CAD21AoDpZ6Xjg=gFrGPnSn4oTRRcwK1EBrWCq9OqOHuAcMMC=w@mail.gmail.com
* Add required database and origin filtering for logical messages.Andres Freund2016-04-13
| | | | | | | | | | | | | | | | | Logical messages, added in 3fe3511d05, during decoding failed to filter messages emitted in other databases and messages emitted "under" a replication origin the output plugin isn't interested in. Add tests to verify that both types of filtering actually work. While touching message.sql remove hunk obsoleted by d25379e. Bump XLOG_PAGE_MAGIC because xl_logical_message changed and because 3fe3511d05 had omitted doing so. 3fe3511d05 additionally didn't bump catversion, but 7a542700d has done so since. Author: Petr Jelinek Reported-By: Andres Freund Discussion: 20160406142513.wotqy3ba3kanr423@alap3.anarazel.de