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* Track replication origin progress for rollbacks.Amit Kapila2021-03-08
| | | | | | | | | | | | | | | | Commit 1eb6d6527a allowed to track replica origin replay progress for 2PC but it was not complete. It misses to properly track the progress for rollback prepared especially it missed updating the code for recovery. Additionally, we need to allow tracking it on subscriber nodes where wal_level might not be logical. It is required to track decoding of 2PC which is committed in PG14 (a271a1b50e) and also nobody complained about this till now so not backpatching it. Author: Amit Kapila Reviewed-by: Michael Paquier and Ajin Cherian Discussion: https://postgr.es/m/CAA4eK1L-kHmMnSdrRW6UhRbCjR7cgh04c+6psY15qzT6ktcd+g@mail.gmail.com
* Remove server and libpq support for old FE/BE protocol version 2.Heikki Linnakangas2021-03-04
| | | | | | | | | | | | | | | | | Protocol version 3 was introduced in PostgreSQL 7.4. There shouldn't be many clients or servers left out there without version 3 support. But as a courtesy, I kept just enough of the old protocol support that we can still send the "unsupported protocol version" error in v2 format, so that old clients can display the message properly. Likewise, libpq still understands v2 ErrorResponse messages when establishing a connection. The impetus to do this now is that I'm working on a patch to COPY FROM, to always prefetch some data. We cannot do that safely with the old protocol, because it requires parsing the input one byte at a time to detect the end-of-copy marker. Reviewed-by: Tom Lane, Alvaro Herrera, John Naylor Discussion: https://www.postgresql.org/message-id/9ec25819-0a8a-d51a-17dc-4150bb3cca3b%40iki.fi
* nbtree page deletion: Add leaftopparent assertion.Peter Geoghegan2021-03-02
| | | | | | Add documenting assertion. This makes it easier to follow how we maintain the top parent link in target subtree's half-dead/leaf level page.
* Fix nbtree page deletion error messages.Peter Geoghegan2021-03-02
| | | | | | | | | | | | Adjust some "can't happen" error messages that assumed that the page deletion target page must be a half-dead page. This assumption was wrong in the case of an internal target page. Simply refer to these pages as the target page instead. Internal pages are never marked half-dead. There is exactly one half-dead page for each subtree undergoing deletion. The half-dead page is also the target subtree's leaf-level page. This has been the case since commit efada2b8, which totally overhauled nbtree page deletion.
* Add TID Range Scans to support efficient scanning ranges of TIDsDavid Rowley2021-02-27
| | | | | | | | | | | | | | | | | | | | | This adds a new executor node named TID Range Scan. The query planner will generate paths for TID Range scans when quals are discovered on base relations which search for ranges on the table's ctid column. These ranges may be open at either end. For example, WHERE ctid >= '(10,0)'; will return all tuples on page 10 and over. To support this, two new optional callback functions have been added to table AM. scan_set_tidrange is used to set the scan range to just the given range of TIDs. scan_getnextslot_tidrange fetches the next tuple in the given range. For AMs were scanning ranges of TIDs would not make sense, these functions can be set to NULL in the TableAmRoutine. The query planner won't generate TID Range Scan Paths in that case. Author: Edmund Horner, David Rowley Reviewed-by: David Rowley, Tomas Vondra, Tom Lane, Andres Freund, Zhihong Yu Discussion: https://postgr.es/m/CAMyN-kB-nFTkF=VA_JPwFNo08S0d-Yk0F741S2B7LDmYAi8eyA@mail.gmail.com
* VACUUM VERBOSE: Count "newly deleted" index pages.Peter Geoghegan2021-02-25
| | | | | | | | | | | | | | | | | | | | | | Teach VACUUM VERBOSE to report on pages deleted by the _current_ VACUUM operation -- these are newly deleted pages. VACUUM VERBOSE continues to report on the total number of deleted pages in the entire index (no change there). The former is a subset of the latter. The distinction between each category of deleted index page only arises with index AMs where page deletion is supported and is decoupled from page recycling for performance reasons. This is follow-up work to commit e5d8a999, which made nbtree store 64-bit XIDs (not 32-bit XIDs) in pages at the point at which they're deleted. Note that the btm_last_cleanup_num_delpages metapage field added by that commit usually gets set to pages_newly_deleted. The exceptions (the scenarios in which they're not equal) all seem to be tricky cases for the implementation (of page deletion and recycling) in general. Author: Peter Geoghegan <pg@bowt.ie> Discussion: https://postgr.es/m/CAH2-WznpdHvujGUwYZ8sihX%3Dd5u-tRYhi-F4wnV2uN2zHpMUXw%40mail.gmail.com
* Use full 64-bit XIDs in deleted nbtree pages.Peter Geoghegan2021-02-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Otherwise we risk "leaking" deleted pages by making them non-recyclable indefinitely. Commit 6655a729 did the same thing for deleted pages in GiST indexes. That work was used as a starting point here. Stop storing an XID indicating the oldest bpto.xact across all deleted though unrecycled pages in nbtree metapages. There is no longer any reason to care about that condition/the oldest XID. It only ever made sense when wraparound was something _bt_vacuum_needs_cleanup() had to consider. The btm_oldest_btpo_xact metapage field has been repurposed and renamed. It is now btm_last_cleanup_num_delpages, which is used to remember how many non-recycled deleted pages remain from the last VACUUM (in practice its value is usually the precise number of pages that were _newly deleted_ during the specific VACUUM operation that last set the field). The general idea behind storing btm_last_cleanup_num_delpages is to use it to give _some_ consideration to non-recycled deleted pages inside _bt_vacuum_needs_cleanup() -- though never too much. We only really need to avoid leaving a truly excessive number of deleted pages in an unrecycled state forever. We only do this to cover certain narrow cases where no other factor makes VACUUM do a full scan, and yet the index continues to grow (and so actually misses out on recycling existing deleted pages). These metapage changes result in a clear user-visible benefit: We no longer trigger full index scans during VACUUM operations solely due to the presence of only 1 or 2 known deleted (though unrecycled) blocks from a very large index. All that matters now is keeping the costs and benefits in balance over time. Fix an issue that has been around since commit 857f9c36, which added the "skip full scan of index" mechanism (i.e. the _bt_vacuum_needs_cleanup() logic). The accuracy of btm_last_cleanup_num_heap_tuples accidentally hinged upon _when_ the source value gets stored. We now always store btm_last_cleanup_num_heap_tuples in btvacuumcleanup(). This fixes the issue because IndexVacuumInfo.num_heap_tuples (the source field) is expected to accurately indicate the state of the table _after_ the VACUUM completes inside btvacuumcleanup(). A backpatchable fix cannot easily be extracted from this commit. A targeted fix for the issue will follow in a later commit, though that won't happen today. I (pgeoghegan) have chosen to remove any mention of deleted pages in the documentation of the vacuum_cleanup_index_scale_factor GUC/param, since the presence of deleted (though unrecycled) pages is no longer of much concern to users. The vacuum_cleanup_index_scale_factor description in the docs now seems rather unclear in any case, and it should probably be rewritten in the near future. Perhaps some passing mention of page deletion will be added back at the same time. Bump XLOG_PAGE_MAGIC due to nbtree WAL records using full XIDs now. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Masahiko Sawada <sawada.mshk@gmail.com> Discussion: https://postgr.es/m/CAH2-WznpdHvujGUwYZ8sihX=d5u-tRYhi-F4wnV2uN2zHpMUXw@mail.gmail.com
* Fix some typos, grammar and style in docs and commentsMichael Paquier2021-02-24
| | | | | | | | The portions fixing the documentation are backpatched where needed. Author: Justin Pryzby Discussion: https://postgr.es/m/20210210235557.GQ20012@telsasoft.com backpatch-through: 9.6
* Reinstate HEAP_XMAX_LOCK_ONLY|HEAP_KEYS_UPDATED as allowedAlvaro Herrera2021-02-23
| | | | | | | | | | | | | | | | | | Commit 866e24d47db1 added an assert that HEAP_XMAX_LOCK_ONLY and HEAP_KEYS_UPDATED cannot appear together, on the faulty assumption that the latter necessarily referred to an update and not a tuple lock; but that's wrong, because SELECT FOR UPDATE can use precisely that combination, as evidenced by the amcheck test case added here. Remove the Assert(), and also patch amcheck's verify_heapam.c to not complain if the combination is found. Also, out of overabundance of caution, update (across all branches) README.tuplock to be more explicit about this. Author: Julien Rouhaud <rjuju123@gmail.com> Reviewed-by: Mahendra Singh Thalor <mahi6run@gmail.com> Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com> Discussion: https://postgr.es/m/20210124061758.GA11756@nol
* Simplify printing of LSNsPeter Eisentraut2021-02-23
| | | | | | | | | | Add a macro LSN_FORMAT_ARGS for use in printf-style printing of LSNs. Convert all applicable code to use it. Reviewed-by: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://www.postgresql.org/message-id/flat/CAExHW5ub5NaTELZ3hJUCE6amuvqAtsSxc7O+uK7y4t9Rrk23cw@mail.gmail.com
* Remove pointless HeapTupleHeaderIndicatesMovedPartitions callsAlvaro Herrera2021-02-22
| | | | | | | | | | | | | | | | Pavan Deolasee recently noted that a few of the HeapTupleHeaderIndicatesMovedPartitions calls added by commit 5db6df0c0117 are useless, since they are done after comparing t_self with t_ctid. But because t_self can never be set to the magical values that indicate that the tuple moved partition, this can never succeed: if the first test fails (so we know t_self equals t_ctid), necessarily the second test will also fail. So these checks can be removed and no harm is done. There's no bug here, just a code legibility issue. Reported-by: Pavan Deolasee <pavan.deolasee@gmail.com> Discussion: https://postgr.es/m/20200929164411.GA15497@alvherre.pgsql
* Initialize atomic variable waitStart in PGPROC, at postmaster startup.Fujii Masao2021-02-22
| | | | | | | | | | | | | | | | | Commit 46d6e5f567 added the atomic variable "waitStart" into PGPROC struct, to store the time at which wait for lock acquisition started. Previously this variable was initialized every time each backend started. Instead, this commit makes postmaster initialize it at the startup, to ensure that the variable should be initialized before any use of it. This commit also moves the code to initialize "waitStart" variable for prepare transaction, from TwoPhaseGetDummyProc() to MarkAsPreparingGuts(). Because MarkAsPreparingGuts() is more proper place to do that since it initializes other PGPROC variables. Author: Fujii Masao Reviewed-by: Atsushi Torikoshi Discussion: https://postgr.es/m/1df88660-6f08-cc6e-b7e2-f85296a2bdab@oss.nttdata.com
* Fix bug in COMMIT AND CHAIN command.Fujii Masao2021-02-19
| | | | | | | | | | | | | | | | | | This commit fixes COMMIT AND CHAIN command so that it starts new transaction immediately even if savepoints are defined within the transaction to commit. Previously COMMIT AND CHAIN command did not in that case because commit 280a408b48 forgot to make CommitTransactionCommand() handle a transaction chaining when the transaction state was TBLOCK_SUBCOMMIT. Also this commit adds the regression test for COMMIT AND CHAIN command when savepoints are defined. Back-patch to v12 where transaction chaining was added. Reported-by: Arthur Nascimento Author: Fujii Masao Reviewed-by: Arthur Nascimento, Vik Fearing Discussion: https://postgr.es/m/16867-3475744069228158@postgresql.org
* Add nbtree README section on page recycling.Peter Geoghegan2021-02-18
| | | | | | | | | | | | | | | | | | | | | | | | Consolidate discussion of how VACUUM places pages in the FSM for recycling by adding a new section that comes after discussion of page deletion. This structure reflects the fact that page recycling is explicitly decoupled from page deletion in Lanin & Shasha's paper. Page recycling in nbtree is an implementation of what the paper calls "the drain technique". This decoupling is an important concept for nbtree VACUUM. Searchers have to detect and recover from concurrent page deletions, but they will never have to reason about concurrent page recycling. Recycling can almost always be thought of as a low level garbage collection operation that asynchronously frees the physical space that backs a logical tree node. Almost all code need only concern itself with logical tree nodes. (Note that "logical tree node" is not currently a term of art in the nbtree code -- this all works implicitly.) This is preparation for an upcoming patch that teaches nbtree VACUUM to remember the details of pages that it deletes on the fly, in local memory. This enables the same VACUUM operation to consider placing its own deleted pages in the FSM later on, when it reaches the end of btvacuumscan().
* nbtree README: move VACUUM linear scan section.Peter Geoghegan2021-02-17
| | | | | | | | | Discuss VACUUM's linear scan after discussion of tuple deletion by VACUUM, but before discussion of page deletion by VACUUM. This progression is a lot more natural. Also tweak the wording a little. It seems unnecessary to talk about how it worked prior to PostgreSQL 8.2.
* Use errmsg_internal for debug messagesPeter Eisentraut2021-02-17
| | | | | | An inconsistent set of debug-level messages was not using errmsg_internal(), thus uselessly exposing the messages to translation work. Fix those.
* Fix heap_page_prune() parameter order confusion introduced in dc7420c2c92.Andres Freund2021-02-15
| | | | | | | | | | | | | Both luckily and unluckily the passed values meant the same for all types. Luckily because that meant my confusion caused no harm, unluckily because otherwise the compiler might have warned... In passing, synchronize parameter names between definition and declaration. Reported-By: Peter Geoghegan <pg@bowt.ie> Author: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/CAH2-Wz=L=nBoepQdH9b5Qd0nMvepFT2CnT6sjWvvpOXa=K8HVQ@mail.gmail.com
* Display the time when the process started waiting for the lock, in pg_locks, ↵Fujii Masao2021-02-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | take 2 This commit adds new column "waitstart" into pg_locks view. This column reports the time when the server process started waiting for the lock if the lock is not held. This information is useful, for example, when examining the amount of time to wait on a lock by subtracting "waitstart" in pg_locks from the current time, and identify the lock that the processes are waiting for very long. This feature uses the current time obtained for the deadlock timeout timer as "waitstart" (i.e., the time when this process started waiting for the lock). Since getting the current time newly can cause overhead, we reuse the already-obtained time to avoid that overhead. Note that "waitstart" is updated without holding the lock table's partition lock, to avoid the overhead by additional lock acquisition. This can cause "waitstart" in pg_locks to become NULL for a very short period of time after the wait started even though "granted" is false. This is OK in practice because we can assume that users are likely to look at "waitstart" when waiting for the lock for a long time. The first attempt of this patch (commit 3b733fcd04) caused the buildfarm member "rorqual" (built with --disable-atomics --disable-spinlocks) to report the failure of the regression test. It was reverted by commit 890d2182a2. The cause of this failure was that the atomic variable for "waitstart" in the dummy process entry created at the end of prepare transaction was not initialized. This second attempt fixes that issue. Bump catalog version. Author: Atsushi Torikoshi Reviewed-by: Ian Lawrence Barwick, Robert Haas, Justin Pryzby, Fujii Masao Discussion: https://postgr.es/m/a96013dc51cdc56b2a2b84fa8a16a993@oss.nttdata.com
* Adjust lazy_scan_heap() accounting comments.Peter Geoghegan2021-02-14
| | | | | Explain which particular LP_DEAD line pointers get accounted for by the tups_vacuumed variable.
* ReadNewTransactionId() -> ReadNextTransactionId().Thomas Munro2021-02-15
| | | | | | | | | The new name conveys the effect better, is more consistent with similar functions ReadNextMultiXactId(), ReadNextFullTransactionId(), and matches the name of the variable that it reads. Reported-by: Peter Geoghegan <pg@bowt.ie> Discussion: https://postgr.es/m/CAH2-WzmVR4SakBXQUdhhPpMf1aYvZCnna5%3DHKa7DAgEmBAg%2B8g%40mail.gmail.com
* README/C-comment: document GiST's NSN valueBruce Momjian2021-02-13
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* Allow multiple xacts during table sync in logical replication.Amit Kapila2021-02-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For the initial table data synchronization in logical replication, we use a single transaction to copy the entire table and then synchronize the position in the stream with the main apply worker. There are multiple downsides of this approach: (a) We have to perform the entire copy operation again if there is any error (network breakdown, error in the database operation, etc.) while we synchronize the WAL position between tablesync worker and apply worker; this will be onerous especially for large copies, (b) Using a single transaction in the synchronization-phase (where we can receive WAL from multiple transactions) will have the risk of exceeding the CID limit, (c) The slot will hold the WAL till the entire sync is complete because we never commit till the end. This patch solves all the above downsides by allowing multiple transactions during the tablesync phase. The initial copy is done in a single transaction and after that, we commit each transaction as we receive. To allow recovery after any error or crash, we use a permanent slot and origin to track the progress. The slot and origin will be removed once we finish the synchronization of the table. We also remove slot and origin of tablesync workers if the user performs DROP SUBSCRIPTION .. or ALTER SUBSCRIPTION .. REFERESH and some of the table syncs are still not finished. The commands ALTER SUBSCRIPTION ... REFRESH PUBLICATION and ALTER SUBSCRIPTION ... SET PUBLICATION ... with refresh option as true cannot be executed inside a transaction block because they can now drop the slots for which we have no provision to rollback. This will also open up the path for logical replication of 2PC transactions on the subscriber side. Previously, we can't do that because of the requirement of maintaining a single transaction in tablesync workers. Bump catalog version due to change of state in the catalog (pg_subscription_rel). Author: Peter Smith, Amit Kapila, and Takamichi Osumi Reviewed-by: Ajin Cherian, Petr Jelinek, Hou Zhijie and Amit Kapila Discussion: https://postgr.es/m/CAA4eK1KHJxaZS-fod-0fey=0tq3=Gkn4ho=8N4-5HWiCfu0H1A@mail.gmail.com
* Remove obsolete IndexBulkDeleteResult stats field.Peter Geoghegan2021-02-11
| | | | | | The pages_removed field is no longer used for anything. It hasn't been possible for an index to physically shrink since old-style VACUUM FULL was removed by commit 0a469c87.
* Fix lack of message pluralizationPeter Eisentraut2021-02-10
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* Fix obsolete FSM remarks in nbtree README.Peter Geoghegan2021-02-09
| | | | | The free space map has used a dedicated relation fork rather than shared memory segments for over a decade.
* Fix permission checks on constraint violation errors on partitions.Heikki Linnakangas2021-02-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a cross-partition UPDATE violates a constraint on the target partition, and the columns in the new partition are in different physical order than in the parent, the error message can reveal columns that the user does not have SELECT permission on. A similar bug was fixed earlier in commit 804b6b6db4. The cause of the bug is that the callers of the ExecBuildSlotValueDescription() function got confused when constructing the list of modified columns. If the tuple was routed from a parent, we converted the tuple to the parent's format, but the list of modified columns was grabbed directly from the child's RTE entry. ExecUpdateLockMode() had a similar issue. That lead to confusion on which columns are key columns, leading to wrong tuple lock being taken on tables referenced by foreign keys, when a row is updated with INSERT ON CONFLICT UPDATE. A new isolation test is added for that corner case. With this patch, the ri_RangeTableIndex field is no longer set for partitions that don't have an entry in the range table. Previously, it was set to the RTE entry of the parent relation, but that was confusing. NOTE: This modifies the ResultRelInfo struct, replacing the ri_PartitionRoot field with ri_RootResultRelInfo. That's a bit risky to backpatch, because it breaks any extensions accessing the field. The change that ri_RangeTableIndex is not set for partitions could potentially break extensions, too. The ResultRelInfos are visible to FDWs at least, and this patch required small changes to postgres_fdw. Nevertheless, this seem like the least bad option. I don't think these fields widely used in extensions; I don't think there are FDWs out there that uses the FDW "direct update" API, other than postgres_fdw. If there is, you will get a compilation error, so hopefully it is caught quickly. Backpatch to 11, where support for both cross-partition UPDATEs, and unique indexes on partitioned tables, were added. Reviewed-by: Amit Langote Security: CVE-2021-3393
* Rename removable xid function for consistency.Peter Geoghegan2021-02-07
| | | | | | | | | | | | GlobalVisIsRemovableFullXid() is now GlobalVisCheckRemovableFullXid(). This is consistent with the general convention for FullTransactionId equivalents of functions that deal with TransactionId values. It now matches the nearby GlobalVisCheckRemovableXid() function, which performs the same check for callers that use TransactionId values. Oversight in commit dc7420c2c92. Discussion: https://postgr.es/m/CAH2-Wzmes12jFNDcVgpU89Vp=r6uLFrE-MT0fjSWGsE70UiNaA@mail.gmail.com
* Clarify some comments around SharedRecoveryState in xlog.cMichael Paquier2021-02-06
| | | | | | | | | SharedRecoveryState has been switched from a boolean to an enum as of commit 4e87c48, but some comments still referred to it as a boolean. Author: Amul Sul Reviewed-by: Dilip Kumar, Kyotaro Horiguchi Discussion: https://postgr.es/m/CAAJ_b97Hf+1SXnm8jySpO+Fhm+-VKFAAce1T_cupUYtnE3Nxig
* Harden nbtree page deletion.Peter Geoghegan2021-02-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | Add some additional defensive checks in the second phase of index deletion to detect and report index corruption during VACUUM, and to avoid having VACUUM become stuck in more cases. The code is still not robust in the presence of a circular chain of sibling links, though it's not clear whether that really matters. This is follow-up work to commit 3a01f68e. The new defensive checks rely on the assumption that there can be no more than one VACUUM operation running for an index at any given time. Remove an old comment suggesting that multiple concurrent VACUUMs need to be considered here. This concern now seems highly unlikely to have any real validity, since we clearly rely on the same assumption in several other places. For example, there are much more recent comments that appear in the same function (added by commit efada2b8e92) that make the same assumption. Also add a CHECK_FOR_INTERRUPTS() to the relevant code path. Contrary to comments added by commit 3a01f68e, it is actually possible to handle interrupts here, at least in the common case where processing takes place at the leaf level. We only hold a pin on leafbuf/target page when stepping right at the leaf level. No backpatch due to the lack of complaints following hardening added to the same area by commit 3a01f68e.
* Improve confusing variable namesPeter Eisentraut2021-02-02
| | | | | | | | | | The prototype calls the second argument of pgstat_progress_update_multi_param() "index", and some callers name their local variable that way. But when the surrounding code deals with index relations, this is confusing, and in at least one case shadowed another variable that is referring to an index relation. Adjust those call sites to have clearer local variable naming, similar to existing callers in indexcmds.c.
* Remove unused _bt_delitems_delete() argument.Peter Geoghegan2021-01-31
| | | | | | | | The latestRemovedXid values used by nbtree deletion operations are determined by _bt_delitems_delete()'s caller, so there is no reason to pass a separate heapRel argument. Oversight in commit d168b666823.
* Retire pg_standby.Thomas Munro2021-01-29
| | | | | | | | | | | | | | pg_standby was useful more than a decade ago, but now it is obsolete. It has been proposed that we retire it many times. Now seems like a good time to finally do it, because "waiting restore commands" are incompatible with a proposed recovery prefetching feature. Discussion: https://postgr.es/m/20201029024412.GP5380%40telsasoft.com Author: Justin Pryzby <pryzby@telsasoft.com> Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi> Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
* In TrimCLOG(), don't reset XactCtl->shared->latest_page_number.Robert Haas2021-01-27
| | | | | | | | | | | | | | | | | | | | | Since the CLOG page number is not recorded directly in the checkpoint record, we have to use ShmemVariableCache->nextXid to figure out the latest CLOG page number at the start of recovery. However, as recovery progresses, replay of CLOG/EXTEND records will update our notion of the latest page number, and we should rely on that being accurate rather than recomputing the value based on an updated notion of nextXid. ShmemVariableCache->nextXid is only an approximation during recovery anyway, whereas CLOG/EXTEND records are an authoritative representation of how the SLRU has been updated. Commit 0fcc2decd485a61321a3220d8f76cb108b082009 makes this simplification possible, as before that change clog_redo() might have injected a bogus value here, and we'd want to get rid of that before entering normal running. Patch by me, reviewed by Heikki Linnakangas. Discussion: http://postgr.es/m/CA+TgmoZYig9+AQodhF5sRXuKkJ=RgFDugLr3XX_dz_F-p=TwTg@mail.gmail.com
* In clog_redo(), don't set XactCtl->shared->latest_page_number.Robert Haas2021-01-27
| | | | | | | | | | | | | | | | | | | | | | The comment is no longer accurate, and hasn't been entirely accurate since Hot Standby was introduced. The original idea here was that StartupCLOG() wouldn't be called until the end of recovery and therefore this value would be uninitialized when this code is reached, but Hot Standby made that true only when hot_standby=off, and commit 1f113abdf87cd085dee3927960bb4f70442b7250 means that this value is now always initialized before replay even starts. The original purpose of this code was to bypass the sanity check in SimpleLruTruncate(), which will no longer occur: now, if something is wrong, that sanity check might trip during recovery. That's probably a good thing, because in the current code base latest_page_number should always be initialized and therefore we expect that the sanity check should pass. If it doesn't, something has gone wrong, and complaining about it is appropriate. Patch by me, reviewed by Heikki Linnakangas. Discussion: http://postgr.es/m/CA+TgmoZYig9+AQodhF5sRXuKkJ=RgFDugLr3XX_dz_F-p=TwTg@mail.gmail.com
* Move StartupCLOG() calls to just after we initialize ShmemVariableCache.Robert Haas2021-01-27
| | | | | | | | | | | | | Previously, the hot_standby=off code path did this at end of recovery, while the hot_standby=on code path did it at the beginning of recovery. It's better to do this in only one place because (a) it's simpler, (b) StartupCLOG() is trivial so trying to postpone the work isn't useful, and (c) this will make it possible to simplify some other logic. Patch by me, reviewed by Heikki Linnakangas. Discussion: http://postgr.es/m/CA+TgmoZYig9+AQodhF5sRXuKkJ=RgFDugLr3XX_dz_F-p=TwTg@mail.gmail.com
* Fix GiST index deletion assert issue.Peter Geoghegan2021-01-26
| | | | | | | | | | | | | Avoid calling heap_index_delete_tuples() with an empty deltids array to avoid an assertion failure. This issue was arguably an oversight in commit b5f58cf2, though the failing assert itself was added by my recent commit d168b666. No backpatch, though, since the oversight is harmless in the back branches. Author: Peter Geoghegan <pg@bowt.ie> Reported-By: Jaime Casanova <jcasanov@systemguards.com.ec> Discussion: https://postgr.es/m/CAJKUy5jscES84n3puE=sYngyF+zpb4wv8UMtuLnLPv5z=6yyNw@mail.gmail.com
* Remove CheckpointLock.Robert Haas2021-01-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Up until now, we've held this lock when performing a checkpoint or restartpoint, but commit 076a055acf3c55314de267c62b03191586d79cf6 back in 2004 and commit 7e48b77b1cebb9a43f9fdd6b17128a0ba36132f9 from 2009, taken together, have removed all need for this. In the present code, there's only ever one process entitled to attempt a checkpoint: either the checkpointer, during normal operation, or the postmaster, during single-user operation. So, we don't need the lock. One possible concern in making this change is that it means that a substantial amount of code where HOLD_INTERRUPTS() was previously in effect due to the preceding LWLockAcquire() will now be running without that. This could mean that ProcessInterrupts() gets called in places from which it didn't before. However, this seems unlikely to do very much, because the checkpointer doesn't have any signal mapped to die(), so it's not clear how, for example, ProcDiePending = true could happen in the first place. Similarly with ClientConnectionLost and recovery conflicts. Also, if there are any such problems, we might want to fix them rather than reverting this, since running lots of code with interrupt handling suspended is generally bad. Patch by me, per an inquiry by Amul Sul. Review by Tom Lane and Michael Paquier. Discussion: http://postgr.es/m/CAAJ_b97XnBBfYeSREDJorFsyoD1sHgqnNuCi=02mNQBUMnA=FA@mail.gmail.com
* Fix hypothetical bug in heap backward scansDavid Rowley2021-01-25
| | | | | | | | | | | | | | | | | | | | | | | | | | Both heapgettup() and heapgettup_pagemode() incorrectly set the first page to scan in a backward scan in which the number of pages to scan was specified by heap_setscanlimits(). The code incorrectly started the scan at the end of the relation when startBlk was 0, or otherwise at startBlk - 1, neither of which is correct when only scanning a subset of pages. The fix here checks if heap_setscanlimits() has changed the number of pages to scan and if so we set the first page to scan as the final page in the specified range during backward scans. Proper adjustment of this code was forgotten when heap_setscanlimits() was added in 7516f5259 back in 9.5. However, practice, nowhere in core code performs backward scans after having used heap_setscanlimits(), yet, it is possible an extension uses the heap functions in this way, hence backpatch. An upcoming patch does use heap_setscanlimits() with backward scans, so this must be fixed before that can go in. Author: David Rowley Discussion: https://postgr.es/m/CAApHDvpGc9h0_oVD2CtgBcxCS1N-qDYZSeBRnUh+0CWJA9cMaA@mail.gmail.com Backpatch-through: 9.5, all supported versions
* Fix COPY FREEZE with CLOBBER_CACHE_ALWAYSTomas Vondra2021-01-24
| | | | | | | | | | | | | This adds code omitted from commit 7db0cd2145 by accident, which had two consequences. Firstly, only rows inserted by heap_multi_insert were frozen as expected when running COPY FREEZE, while heap_insert left rows unfrozen. That however includes rows in TOAST tables, so a lot of data might have been left unfrozen. Secondly, page might have been left partially empty after relcache invalidation. This addresses both of those issues. Discussion: https://postgr.es/m/CABOikdN-ptGv0mZntrK2Q8OtfUuAjqaYMGmkdU1dCKFtUxVLrg@mail.gmail.com
* Fix bug in detecting concurrent page splits in GiST insertHeikki Linnakangas2021-01-20
| | | | | | | | | | | | | | | | | In commit 9eb5607e699, I got the condition on checking for split or deleted page wrong: I used && instead of ||. The comment correctly said "concurrent split _or_ deletion". As a result, GiST insertion could miss a concurrent split, and insert to wrong page. Duncan Sands demonstrated this with a test script that did a lot of concurrent inserts. Backpatch to v12, where this was introduced. REINDEX is required to fix indexes that were affected by this bug. Backpatch-through: 12 Reported-by: Duncan Sands Discussion: https://www.postgresql.org/message-id/a9690483-6c6c-3c82-c8ba-dc1a40848f11%40deepbluecap.com
* Pause recovery for insufficient parameter settingsPeter Eisentraut2021-01-18
| | | | | | | | | | | | | | | | | | When certain parameters are changed on a physical replication primary, this is communicated to standbys using the XLOG_PARAMETER_CHANGE WAL record. The standby then checks whether its own settings are at least as big as the ones on the primary. If not, the standby shuts down with a fatal error. This patch changes this behavior for hot standbys to pause recovery at that point instead. That allows read traffic on the standby to continue while database administrators figure out next steps. When recovery is unpaused, the server shuts down (as before). The idea is to fix the parameters while recovery is paused and then restart when there is a maintenance window. Reviewed-by: Sergei Kornilov <sk@zsrv.org> Discussion: https://www.postgresql.org/message-id/flat/4ad69a4c-cc9b-0dfe-0352-8b1b0cd36c7b@2ndquadrant.com
* Set PD_ALL_VISIBLE and visibility map bits in COPY FREEZETomas Vondra2021-01-17
| | | | | | | | | | | | | | | | | | Make sure COPY FREEZE marks the pages as PD_ALL_VISIBLE and updates the visibility map. Until now we only marked individual tuples as frozen, but page-level flags were not updated, so the first VACUUM after the COPY FREEZE had to rewrite the whole table. This is a fairly old patch, and multiple people worked on it. The first version was written by Jeff Janes, and then reworked by Pavan Deolasee and Anastasia Lubennikova. Author: Anastasia Lubennikova, Pavan Deolasee, Jeff Janes Reviewed-by: Kuntal Ghosh, Jeff Janes, Tomas Vondra, Masahiko Sawada, Andres Freund, Ibrar Ahmed, Robert Haas, Tatsuro Ishii, Darafei Praliaskouski Discussion: https://postgr.es/m/CABOikdN-ptGv0mZntrK2Q8OtfUuAjqaYMGmkdU1dCKFtUxVLrg@mail.gmail.com Discussion: https://postgr.es/m/CAMkU%3D1w3osJJ2FneELhhNRLxfZitDgp9FPHee08NT2FQFmz_pQ%40mail.gmail.com
* Prevent excess SimpleLruTruncate() deletion.Noah Misch2021-01-16
| | | | | | | | | | | | | | | | | Every core SLRU wraps around. With the exception of pg_notify, the wrap point can fall in the middle of a page. Account for this in the PagePrecedes callback specification and in SimpleLruTruncate()'s use of said callback. Update each callback implementation to fit the new specification. This changes SerialPagePrecedesLogically() from the style of asyncQueuePagePrecedes() to the style of CLOGPagePrecedes(). (Whereas pg_clog and pg_serial share a key space, pg_serial is nothing like pg_notify.) The bug fixed here has the same symptoms and user followup steps as 592a589a04bd456410b853d86bd05faa9432cbbb. Back-patch to 9.5 (all supported versions). Reviewed by Andrey Borodin and (in earlier versions) by Tom Lane. Discussion: https://postgr.es/m/20190202083822.GC32531@gust.leadboat.com
* Fix O(N^2) stat() calls when recycling WAL segmentsMichael Paquier2021-01-15
| | | | | | | | | | | | | | | | | | The counter tracking the last segment number recycled was getting initialized when recycling one single segment, while it should be used across a full cycle of segments recycled to prevent useless checks related to entries already recycled. This performance issue has been introduced by b2a5545, and it was first implemented in 61b86142. No backpatch is done per the lack of field complaints. Reported-by: Andres Freund, Thomas Munro Author: Michael Paquier Reviewed-By: Andres Freund Discussion: https://postgr.es/m/20170621211016.eln6cxxp3jrv7m4m@alap3.anarazel.de Discussion: https://postgr.es/m/CA+hUKG+DRiF9z1_MU4fWq+RfJMxP7zjoptfcmuCFPeO4JM2iVg@mail.gmail.com
* Enhance nbtree index tuple deletion.Peter Geoghegan2021-01-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Teach nbtree and heapam to cooperate in order to eagerly remove duplicate tuples representing dead MVCC versions. This is "bottom-up deletion". Each bottom-up deletion pass is triggered lazily in response to a flood of versions on an nbtree leaf page. This usually involves a "logically unchanged index" hint (these are produced by the executor mechanism added by commit 9dc718bd). The immediate goal of bottom-up index deletion is to avoid "unnecessary" page splits caused entirely by version duplicates. It naturally has an even more useful effect, though: it acts as a backstop against accumulating an excessive number of index tuple versions for any given _logical row_. Bottom-up index deletion complements what we might now call "top-down index deletion": index vacuuming performed by VACUUM. Bottom-up index deletion responds to the immediate local needs of queries, while leaving it up to autovacuum to perform infrequent clean sweeps of the index. The overall effect is to avoid certain pathological performance issues related to "version churn" from UPDATEs. The previous tableam interface used by index AMs to perform tuple deletion (the table_compute_xid_horizon_for_tuples() function) has been replaced with a new interface that supports certain new requirements. Many (perhaps all) of the capabilities added to nbtree by this commit could also be extended to other index AMs. That is left as work for a later commit. Extend deletion of LP_DEAD-marked index tuples in nbtree by adding logic to consider extra index tuples (that are not LP_DEAD-marked) for deletion in passing. This increases the number of index tuples deleted significantly in many cases. The LP_DEAD deletion process (which is now called "simple deletion" to clearly distinguish it from bottom-up deletion) won't usually need to visit any extra table blocks to check these extra tuples. We have to visit the same table blocks anyway to generate a latestRemovedXid value (at least in the common case where the index deletion operation's WAL record needs such a value). Testing has shown that the "extra tuples" simple deletion enhancement increases the number of index tuples deleted with almost any workload that has LP_DEAD bits set in leaf pages. That is, it almost never fails to delete at least a few extra index tuples. It helps most of all in cases that happen to naturally have a lot of delete-safe tuples. It's not uncommon for an individual deletion operation to end up deleting an order of magnitude more index tuples compared to the old naive approach (e.g., custom instrumentation of the patch shows that this happens fairly often when the regression tests are run). Add a further enhancement that augments simple deletion and bottom-up deletion in indexes that make use of deduplication: Teach nbtree's _bt_delitems_delete() function to support granular TID deletion in posting list tuples. It is now possible to delete individual TIDs from posting list tuples provided the TIDs have a tableam block number of a table block that gets visited as part of the deletion process (visiting the table block can be triggered directly or indirectly). Setting the LP_DEAD bit of a posting list tuple is still an all-or-nothing thing, but that matters much less now that deletion only needs to start out with the right _general_ idea about which index tuples are deletable. Bump XLOG_PAGE_MAGIC because xl_btree_delete changed. No bump in BTREE_VERSION, since there are no changes to the on-disk representation of nbtree indexes. Indexes built on PostgreSQL 12 or PostgreSQL 13 will automatically benefit from bottom-up index deletion (i.e. no reindexing required) following a pg_upgrade. The enhancement to simple deletion is available with all B-Tree indexes following a pg_upgrade, no matter what PostgreSQL version the user upgrades from. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Heikki Linnakangas <hlinnaka@iki.fi> Reviewed-By: Victor Yegorov <vyegorov@gmail.com> Discussion: https://postgr.es/m/CAH2-Wzm+maE3apHB8NOtmM=p-DO65j2V5GzAWCOEEuy3JZgb2g@mail.gmail.com
* Pass down "logically unchanged index" hint.Peter Geoghegan2021-01-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add an executor aminsert() hint mechanism that informs index AMs that the incoming index tuple (the tuple that accompanies the hint) is not being inserted by execution of an SQL statement that logically modifies any of the index's key columns. The hint is received by indexes when an UPDATE takes place that does not apply an optimization like heapam's HOT (though only for indexes where all key columns are logically unchanged). Any index tuple that receives the hint on insert is expected to be a duplicate of at least one existing older version that is needed for the same logical row. Related versions will typically be stored on the same index page, at least within index AMs that apply the hint. Recognizing the difference between MVCC version churn duplicates and true logical row duplicates at the index AM level can help with cleanup of garbage index tuples. Cleanup can intelligently target tuples that are likely to be garbage, without wasting too many cycles on less promising tuples/pages (index pages with little or no version churn). This is infrastructure for an upcoming commit that will teach nbtree to perform bottom-up index deletion. No index AM actually applies the hint just yet. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Victor Yegorov <vyegorov@gmail.com> Discussion: https://postgr.es/m/CAH2-Wz=CEKFa74EScx_hFVshCOn6AA5T-ajFASTdzipdkLTNQQ@mail.gmail.com
* Fix thinko in commentAlvaro Herrera2021-01-12
| | | | | | | | This comment has been wrong since its introduction in commit 2c03216d8311. Author: Masahiko Sawada <sawada.mshk@gmail.com> Discussion: https://postgr.es/m/CAD21AoAzz6qipFJBbGEaHmyWxvvNDp8httbwLR9tUQWaTjUs2Q@mail.gmail.com
* Use vectored I/O to fill new WAL segments.Thomas Munro2021-01-11
| | | | | | | | | | | | | Instead of making many block-sized write() calls to fill a new WAL file with zeroes, make a smaller number of pwritev() calls (or various emulations). The actual number depends on the OS's IOV_MAX, which PG_IOV_MAX currently caps at 32. That means we'll write 256kB per call on typical systems. We may want to tune the number later with more experience. Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/CA%2BhUKGJA%2Bu-220VONeoREBXJ9P3S94Y7J%2BkqCnTYmahvZJwM%3Dg%40mail.gmail.com
* Standardize one aspect of rmgr desc output.Peter Geoghegan2021-01-04
| | | | | | | | | | | | | Bring heap and hash rmgr desc output in line with nbtree and GiST desc output by using the name latestRemovedXid for all fields that output the contents of the latestRemovedXid field from the WAL record's C struct (stop using local variants). This seems like a clear improvement because latestRemovedXid is a symbol name that already appears across many different source files, and so is probably much more recognizable. Discussion: https://postgr.es/m/CAH2-Wzkt_Rs4VqPSCk87nyjPAAEmWL8STU9zgET_83EF5YfrLw@mail.gmail.com
* Replace remaining uses of "whitelist".Thomas Munro2021-01-05
| | | | | | | | Instead describe the action that the list effects, or just use "list" where the meaning is obvious from context. Author: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org> Discussion: https://postgr.es/m/20200615182235.x7lch5n6kcjq4aue%40alap3.anarazel.de