147 Commits (fc22b6623b6b3bab3cb057ccd282c2bfad1a0b30)

Author	SHA1	Message	Date
Peter Eisentraut	fc22b6623b	Generated columns ... This is an SQL-standard feature that allows creating columns that are computed from expressions rather than assigned, similar to a view or materialized view but on a column basis. This implements one kind of generated column: stored (computed on write). Another kind, virtual (computed on read), is planned for the future, and some room is left for it. Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/b151f851-4019-bdb1-699e-ebab07d2f40a@2ndquadrant.com	7 years ago
Andres Freund	9a8ee1dc65	tableam: Add and use table_fetch_row_version(). ... This is essentially the tableam version of heapam_fetch(), i.e. fetching a tuple identified by a tid, performing visibility checks. Note that this different from table_index_fetch_tuple(), which is for index lookups. It therefore has to handle a tid pointing to an earlier version of a tuple if the AM uses an optimization like heap's HOT. Add comments to that end. This commit removes the stats_relation argument from heap_fetch, as it's been unused for a long time. Author: Andres Freund Reviewed-By: Haribabu Kommi Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de	7 years ago
Andres Freund	5db6df0c01	tableam: Add tuple_{insert, delete, update, lock} and use. ... This adds new, required, table AM callbacks for insert/delete/update and lock_tuple. To be able to reasonably use those, the EvalPlanQual mechanism had to be adapted, moving more logic into the AM. Previously both delete/update/lock call-sites and the EPQ mechanism had to have awareness of the specific tuple format to be able to fetch the latest version of a tuple. Obviously that needs to be abstracted away. To do so, move the logic that find the latest row version into the AM. lock_tuple has a new flag argument, TUPLE_LOCK_FLAG_FIND_LAST_VERSION, that forces it to lock the last version, rather than the current one. It'd have been possible to do so via a separate callback as well, but finding the last version usually also necessitates locking the newest version, making it sensible to combine the two. This replaces the previous use of EvalPlanQualFetch(). Additionally HeapTupleUpdated, which previously signaled either a concurrent update or delete, is now split into two, to avoid callers needing AM specific knowledge to differentiate. The move of finding the latest row version into tuple_lock means that encountering a row concurrently moved into another partition will now raise an error about "tuple to be locked" rather than "tuple to be updated/deleted" - which is accurate, as that always happens when locking rows. While possible slightly less helpful for users, it seems like an acceptable trade-off. As part of this commit HTSU_Result has been renamed to TM_Result, and its members been expanded to differentiated between updating and deleting. HeapUpdateFailureData has been renamed to TM_FailureData. The interface to speculative insertion is changed so nodeModifyTable.c does not have to set the speculative token itself anymore. Instead there's a version of tuple_insert, tuple_insert_speculative, that performs the speculative insertion (without requiring a flag to signal that fact), and the speculative insertion is either made permanent with table_complete_speculative(succeeded = true) or aborted with succeeded = false). Note that multi_insert is not yet routed through tableam, nor is COPY. Changing multi_insert requires changes to copy.c that are large enough to better be done separately. Similarly, although simpler, CREATE TABLE AS and CREATE MATERIALIZED VIEW are also only going to be adjusted in a later commit. Author: Andres Freund and Haribabu Kommi Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20190313003903.nwvrxi7rw3ywhdel@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql	7 years ago
Andres Freund	c2fe139c20	tableam: Add and use scan APIs. ... Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql	7 years ago
Robert Haas	898e5e3290	Allow ATTACH PARTITION with only ShareUpdateExclusiveLock. ... We still require AccessExclusiveLock on the partition itself, because otherwise an insert that violates the newly-imposed partition constraint could be in progress at the same time that we're changing that constraint; only the lock level on the parent relation is weakened. To make this safe, we have to cope with (at least) three separate problems. First, relevant DDL might commit while we're in the process of building a PartitionDesc. If so, find_inheritance_children() might see a new partition while the RELOID system cache still has the old partition bound cached, and even before invalidation messages have been queued. To fix that, if we see that the pg_class tuple seems to be missing or to have a null relpartbound, refetch the value directly from the table. We can't get the wrong value, because DETACH PARTITION still requires AccessExclusiveLock throughout; if we ever want to change that, this will need more thought. In testing, I found it quite difficult to hit even the null-relpartbound case; the race condition is extremely tight, but the theoretical risk is there. Second, successive calls to RelationGetPartitionDesc might not return the same answer. The query planner will get confused if lookup up the PartitionDesc for a particular relation does not return a consistent answer for the entire duration of query planning. Likewise, query execution will get confused if the same relation seems to have a different PartitionDesc at different times. Invent a new PartitionDirectory concept and use it to ensure consistency. This ensures that a single invocation of either the planner or the executor sees the same view of the PartitionDesc from beginning to end, but it does not guarantee that the planner and the executor see the same view. Since this allows pointers to old PartitionDesc entries to survive even after a relcache rebuild, also postpone removing the old PartitionDesc entry until we're certain no one is using it. For the most part, it seems to be OK for the planner and executor to have different views of the PartitionDesc, because the executor will just ignore any concurrently added partitions which were unknown at plan time; those partitions won't be part of the inheritance expansion, but invalidation messages will trigger replanning at some point. Normally, this happens by the time the very next command is executed, but if the next command acquires no locks and executes a prepared query, it can manage not to notice until a new transaction is started. We might want to tighten that up, but it's material for a separate patch. There would still be a small window where a query that started just after an ATTACH PARTITION command committed might fail to notice its results -- but only if the command starts before the commit has been acknowledged to the user. All in all, the warts here around serializability seem small enough to be worth accepting for the considerable advantage of being able to add partitions without a full table lock. Although in general the consequences of new partitions showing up between planning and execution are limited to the query not noticing the new partitions, run-time partition pruning will get confused in that case, so that's the third problem that this patch fixes. Run-time partition pruning assumes that indexes into the PartitionDesc are stable between planning and execution. So, add code so that if new partitions are added between plan time and execution time, the indexes stored in the subplan_map[] and subpart_map[] arrays within the plan's PartitionedRelPruneInfo get adjusted accordingly. There does not seem to be a simple way to generalize this scheme to cope with partitions that are removed, mostly because they could then get added back again with different bounds, but it works OK for added partitions. This code does not try to ensure that every backend participating in a parallel query sees the same view of the PartitionDesc. That currently doesn't matter, because we never pass PartitionDesc indexes between backends. Each backend will ignore the concurrently added partitions which it notices, and it doesn't matter if different backends are ignoring different sets of concurrently added partitions. If in the future that matters, for example because we allow writes in parallel query and want all participants to do tuple routing to the same set of partitions, the PartitionDirectory concept could be improved to share PartitionDescs across backends. There is a draft patch to serialize and restore PartitionDescs on the thread where this patch was discussed, which may be a useful place to start. Patch by me. Thanks to Alvaro Herrera, David Rowley, Simon Riggs, Amit Langote, and Michael Paquier for discussion, and to Alvaro Herrera for some review. Discussion: http://postgr.es/m/CA+Tgmobt2upbSocvvDej3yzokd7AkiT+PvgFH+a9-5VV1oJNSQ@mail.gmail.com Discussion: http://postgr.es/m/CA+TgmoZE0r9-cyA-aY6f8WFEROaDLLL7Vf81kZ8MtFCkxpeQSw@mail.gmail.com Discussion: http://postgr.es/m/CA+TgmoY13KQZF-=HNTrt9UYWYx3_oYOQpu9ioNT49jGgiDpUEA@mail.gmail.com	7 years ago
Andres Freund	277cb78983	Don't reuse slots between root and partition in ON CONFLICT ... UPDATE. ... Until now the the slot to store the conflicting tuple, and the result of the ON CONFLICT SET, where reused between partitions. That necessitated changing slots descriptor when switching partitions. Besides the overhead of switching descriptors on a slot (which requires memory allocations and prevents JITing), that's importantly also problematic for tableam. There individual partitions might belong to different tableams, needing different kinds of slots. In passing also fix ExecOnConflictUpdate to clear the existing slot at exit. Otherwise that slot could continue to hold a pin till the query ends, which could be far too long if the input data set is large, and there's no further conflicts. While previously also problematic, it's now more important as there will be more such slots when partitioned. Author: Andres Freund Reviewed-By: Robert Haas, David Rowley Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de	7 years ago
Andres Freund	ad0bda5d24	Store tuples for EvalPlanQual in slots, rather than as HeapTuples. ... For the upcoming pluggable table access methods it's quite inconvenient to store tuples as HeapTuples, as that'd require converting tuples from a their native format into HeapTuples. Instead use slots to manage epq tuples. To fit into that scheme, change the foreign data wrapper callback RefetchForeignRow, to store the tuple in a slot. Insist on using the caller provided slot, so it conveniently can be stored in the corresponding EPQ slot. As there is no in core user of RefetchForeignRow, that change was done blindly, but we plan to test that soon. To avoid duplicating that work for row locks, move row locks to just directly use the EPQ slots - it previously temporarily stored tuples in LockRowsState.lr_curtuples, but that doesn't seem beneficial, given we'd possibly end up with a significant number of additional slots. The behaviour of es_epqTupleSet[rti -1] is now checked by es_epqTupleSlot[rti -1] != NULL, as that is distinguishable from a slot containing an empty tuple. Author: Andres Freund, Haribabu Kommi, Ashutosh Bapat Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de	7 years ago
Andres Freund	253655116b	Don't superfluously materialize slot after DELETE from an FDW. ... Previously that was needed to safely store the table oid, but after b8d71745ea that's not necessary anymore. Author: Andres Freund	7 years ago
Andres Freund	ff11e7f4b9	Use slots in trigger infrastructure, except for the actual invocation. ... In preparation for abstracting table storage, convert trigger.c to track tuples in slots. Which also happens to make code calling triggers simpler. As the calling interface for triggers themselves is not changed in this patch, HeapTuples still are extracted from the slot at that time. But that's handled solely inside trigger.c, not visible to callers. It's quite likely that we'll want to revise the external trigger interface, but that's a separate large project. As part of this work the slots used for old/new/return tuples are moved from EState into ResultRelInfo, as different updated tables might need different slots. The slots are now also now created on-demand, which is good both from an efficiency POV, but also makes the modifying code simpler. Author: Andres Freund, Amit Khandekar and Ashutosh Bapat Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de	7 years ago
Andres Freund	b8d71745ea	Store table oid and tuple's tid in tuple slots directly. ... After the introduction of tuple table slots all table AMs need to support returning the table oid of the tuple stored in a slot created by said AM. It does not make sense to re-implement that in every AM, therefore move handling of table OIDs into the TupleTableSlot structure itself. It's possible that we, at a later date, might want to get rid of HeapTupleData.t_tableOid entirely, but doing so before the abstractions for table AMs are integrated turns out to be too hard, so delay that for now. Similarly, every AM needs to support the concept of a tuple identifier (tid / item pointer) for its tuples. It's quite possible that we'll generalize the exact form of a tid at a future point (to allow for things like index organized tables), but for now many parts of the code know about tids, so there's not much point in abstracting tids away. Therefore also move into slot (rather than providing API to set/get the tid associated with the tuple in a slot). Once table AM includes insert/updating/deleting tuples, the responsibility to set the correct tid after such an action will move into that. After that change, code doing such modifications, should not have to deal with HeapTuples directly anymore. Author: Andres Freund, Haribabu Kommi and Ashutosh Bapat Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de	7 years ago
Andres Freund	c91560defc	Move remaining code from tqual.[ch] to heapam.h / heapam_visibility.c. ... Given these routines are heap specific, and that there will be more generic visibility support in via table AM, it makes sense to move the prototypes to heapam.h (routines like HeapTupleSatisfiesVacuum will not be exposed in a generic fashion, because they are too storage specific). Similarly, the code in tqual.c is specific to heap, so moving it into access/heap/ makes sense. Author: Andres Freund Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de	7 years ago
Andres Freund	148e632c05	Fix parent of WCO qual. ... The parent of some WCO expressions was, apparently by accident, set to the the source of DML queries, rather than the target table. This causes problems for the upcoming pluggable storage work, because the target and source table might be of different storage types. It's possible that this is already problematic, but neither experimenting nor inquiries on -hackers have found them. So don't backpatch for now. Author: Andres Freund Discussion: https://postgr.es/m/20181205225213.hiwa3kgoxeybqcqv@alap3.anarazel.de	7 years ago
Andres Freund	4c850ecec6	Don't include heapam.h from others headers. ... heapam.h previously was included in a number of widely used headers (e.g. execnodes.h, indirectly in executor.h, ...). That's problematic on its own, as heapam.h contains a lot of low-level details that don't need to be exposed that widely, but becomes more problematic with the upcoming introduction of pluggable table storage - it seems inappropriate for heapam.h to be included that widely afterwards. heapam.h was largely only included in other headers to get the HeapScanDesc typedef (which was defined in heapam.h, even though HeapScanDescData is defined in relscan.h). The better solution here seems to be to just use the underlying struct (forward declared where necessary). Similar for BulkInsertState. Another problem was that LockTupleMode was used in executor.h - parts of the file tried to cope without heapam.h, but due to the fact that it indirectly included it, several subsequent violations of that goal were not not noticed. We could just reuse the approach of declaring parameters as int, but it seems nicer to move LockTupleMode to lockoptions.h - that's not a perfect location, but also doesn't seem bad. As a number of files relied on implicitly included heapam.h, a significant number of files grew an explicit include. It's quite probably that a few external projects will need to do the same. Author: Andres Freund Reviewed-By: Alvaro Herrera Discussion: https://postgr.es/m/20190114000701.y4ttcb74jpskkcfb@alap3.anarazel.de	7 years ago
Bruce Momjian	97c39498e5	Update copyright for 2019 ... Backpatch-through: certain files through 9.4	7 years ago
Andres Freund	578b229718	Remove WITH OIDS support, change oid catalog column visibility. ... Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de	7 years ago
Andres Freund	4da597edf1	Make TupleTableSlots extensible, finish split of existing slot type. ... This commit completes the work prepared in 1a0586de36, splitting the old TupleTableSlot implementation (which could store buffer, heap, minimal and virtual slots) into four different slot types. As described in the aforementioned commit, this is done with the goal of making tuple table slots extensible, to allow for pluggable table access methods. To achieve runtime extensibility for TupleTableSlots, operations on slots that can differ between types of slots are performed using the TupleTableSlotOps struct provided at slot creation time. That includes information from the size of TupleTableSlot struct to be allocated, initialization, deforming etc. See the struct's definition for more detailed information about callbacks TupleTableSlotOps. I decided to rename TTSOpsBufferTuple to TTSOpsBufferHeapTuple and ExecCopySlotTuple to ExecCopySlotHeapTuple, as that seems more consistent with other naming introduced in recent patches. There's plenty optimization potential in the slot implementation, but according to benchmarking the state after this commit has similar performance characteristics to before this set of changes, which seems sufficient. There's a few changes in execReplication.c that currently need to poke through the slot abstraction, that'll be repaired once the pluggable storage patchset provides the necessary infrastructure. Author: Andres Freund and Ashutosh Bapat, with changes by Amit Khandekar Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de	7 years ago
Alvaro Herrera	3f2393edef	Redesign initialization of partition routing structures ... This speeds up write operations (INSERT, UPDATE, DELETE, COPY, as well as the future MERGE) on partitioned tables. This changes the setup for tuple routing so that it does far less work during the initial setup and pushes more work out to when partitions receive tuples. PartitionDispatchData structs for sub-partitioned tables are only created when a tuple gets routed through it. The possibly large arrays in the PartitionTupleRouting struct have largely been removed. The partitions[] array remains but now never contains any NULL gaps. Previously the NULLs had to be skipped during ExecCleanupTupleRouting(), which could add a large overhead to the cleanup when the number of partitions was large. The partitions[] array is allocated small to start with and only enlarged when we route tuples to enough partitions that it runs out of space. This allows us to keep simple single-row partition INSERTs running quickly. Redesign The arrays in PartitionTupleRouting which stored the tuple translation maps have now been removed. These have been moved out into a PartitionRoutingInfo struct which is an additional field in ResultRelInfo. The find_all_inheritors() call still remains by far the slowest part of ExecSetupPartitionTupleRouting(). This commit just removes the other slow parts. In passing also rename the tuple translation maps from being ParentToChild and ChildToParent to being RootToPartition and PartitionToRoot. The old names mislead you into thinking that a partition of some sub-partitioned table would translate to the rowtype of the sub-partitioned table rather than the root partitioned table. Authors: David Rowley and Amit Langote, heavily revised by Álvaro Herrera Testing help from Jesper Pedersen and Kato Sho. Discussion: https://postgr.es/m/CAKJS1f_1RJyFquuCKRFHTdcXqoPX-PYqAd7nz=GVBwvGh4a6xA@mail.gmail.com	7 years ago
Andres Freund	1a0586de36	Introduce notion of different types of slots (without implementing them). ... Upcoming work intends to allow pluggable ways to introduce new ways of storing table data. Accessing those table access methods from the executor requires TupleTableSlots to be carry tuples in the native format of such storage methods; otherwise there'll be a significant conversion overhead. Different access methods will require different data to store tuples efficiently (just like virtual, minimal, heap already require fields in TupleTableSlot). To allow that without requiring additional pointer indirections, we want to have different structs (embedding TupleTableSlot) for different types of slots. Thus different types of slots are needed, which requires adapting creators of slots. The slot that most efficiently can represent a type of tuple in an executor node will often depend on the type of slot a child node uses. Therefore we need to track the type of slot is returned by nodes, so parent slots can create slots based on that. Relatedly, JIT compilation of tuple deforming needs to know which type of slot a certain expression refers to, so it can create an appropriate deforming function for the type of tuple in the slot. But not all nodes will only return one type of slot, e.g. an append node will potentially return different types of slots for each of its subplans. Therefore add function that allows to query the type of a node's result slot, and whether it'll always be the same type (whether it's fixed). This can be queried using ExecGetResultSlotOps(). The scan, result, inner, outer type of slots are automatically inferred from ExecInitScanTupleSlot(), ExecInitResultSlot(), left/right subtrees respectively. If that's not correct for a node, that can be overwritten using new fields in PlanState. This commit does not introduce the actually abstracted implementation of different kind of TupleTableSlots, that will be left for a followup commit. The different types of slots introduced will, for now, still use the same backing implementation. While this already partially invalidates the big comment in tuptable.h, it seems to make more sense to update it later, when the different TupleTableSlot implementations actually exist. Author: Ashutosh Bapat and Andres Freund, with changes by Amit Khandekar Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de	7 years ago
Andres Freund	763f2edd92	Rejigger materializing and fetching a HeapTuple from a slot. ... Previously materializing a slot always returned a HeapTuple. As current work aims to reduce the reliance on HeapTuples (so other storage systems can work efficiently), that needs to change. Thus split the tasks of materializing a slot (i.e. making it independent from the underlying storage / other memory contexts) from fetching a HeapTuple from the slot. For brevity, allow to fetch a HeapTuple from a slot and materializing the slot at the same time, controlled by a parameter. For now some callers of ExecFetchSlotHeapTuple, with materialize = true, expect that changes to the heap tuple will be reflected in the underlying slot. Those places will be adapted in due course, so while not pretty, that's OK for now. Also rename ExecFetchSlotTuple to ExecFetchSlotHeapTupleDatum and ExecFetchSlotTupleDatum to ExecFetchSlotHeapTupleDatum, as it's likely that future storage methods will need similar methods. There already is ExecFetchSlotMinimalTuple, so the new names make the naming scheme more coherent. Author: Ashutosh Bapat and Andres Freund, with changes by Amit Khandekar Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de	7 years ago
Andres Freund	c058fc2a2b	Rationalize expression context reset in ExecModifyTable(). ... The current pattern of reseting expressions both in ExecProcessReturning() and ExecOnConflictUpdate() makes it harder than necessary to reason about memory lifetimes. It also requires materializing slots unnecessarily, although this patch doesn't take advantage of the fact that that's not necessary anymore. Instead reset the expression context once for each input tuple. Author: Ashutosh Bapat Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de	7 years ago
Andres Freund	1ef6bd2954	Don't require return slots for nodes without projection. ... In a lot of nodes the return slot is not required. That can either be because the node doesn't do any projection (say an Append node), or because the node does perform projections but the projection is optimized away because the projection would yield an identical row. Slots aren't that small, especially for wide rows, so it's worthwhile to avoid creating them. It's not possible to just skip creating the slot - it's currently used to determine the tuple descriptor returned by ExecGetResultType(). So separate the determination of the result type from the slot creation. The work previously done internally ExecInitResultTupleSlotTL() can now also be done separately with ExecInitResultTypeTL() and ExecInitResultSlot(). That way nodes that aren't guaranteed to need a result slot, can use ExecInitResultTypeTL() to determine the result type of the node, and ExecAssignScanProjectionInfo() (via ExecConditionalAssignProjectionInfo()) determines that a result slot is needed, it is created with ExecInitResultSlot(). Besides the advantage of avoiding to create slots that then are unused, this is necessary preparation for later patches around tuple table slot abstraction. In particular separating the return descriptor and slot is a prerequisite to allow JITing of tuple deforming with knowledge of the underlying tuple format, and to avoid unnecessarily creating JITed tuple deforming for virtual slots. This commit removes a redundant argument from ExecInitResultTupleSlotTL(). While this commit touches a lot of the relevant lines anyway, it'd normally still not worthwhile to cause breakage, except that aforementioned later commits will touch *all* ExecInitResultTupleSlotTL() callers anyway (but fits worse thematically). Author: Andres Freund Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de	7 years ago
Andres Freund	c5257345ef	Move TupleTableSlots boolean member into one flag variable. ... There's several reasons for this change: 1) It reduces the total size of TupleTableSlot / reduces alignment padding, making the commonly accessed members fit into a single cacheline (but we currently do not force proper alignment, so that's not yet guaranteed to be helpful) 2) Combining the booleans into a flag allows to combine read/writes from memory. 3) With the upcoming slot abstraction changes, it allows to have core and extended flags, in a memory efficient way. Author: Ashutosh Bapat and Andres Freund Discussion: https://postgr.es/m/20180220224318.gw4oe5jadhpmcdnm@alap3.anarazel.de	7 years ago
Andres Freund	cc2905e963	Use slots more widely in tuple mapping code and make naming more consistent. ... It's inefficient to use a single slot for mapping between tuple descriptors for multiple tuples, as previously done when using ConvertPartitionTupleSlot(), as that means the slot's tuple descriptors change for every tuple. Previously we also, via ConvertPartitionTupleSlot(), built new tuples after the mapping even in cases where we, immediately afterwards, access individual columns again. Refactor the code so one slot, on demand, is used for each partition. That avoids having to change the descriptor (and allows to use the more efficient "fixed" tuple slots). Then use slot->slot mapping, to avoid unnecessarily forming a tuple. As the naming between the tuple and slot mapping functions wasn't consistent, rename them to execute_attr_map_{tuple,slot}. It's likely that we'll also rename convert_tuples_by_* to denote that these functions "only" build a map, but that's left for later. Author: Amit Khandekar and Amit Langote, editorialized by me Reviewed-By: Amit Langote, Amit Khandekar, Andres Freund Discussion: https://postgr.es/m/CAJ3gD9fR0wRNeAE8VqffNTyONS_UfFPRpqxhnD9Q42vZB+Jvpg@mail.gmail.com https://postgr.es/m/e4f9d743-cd4b-efb0-7574-da21d86a7f36%40lab.ntt.co.jp Backpatch: -	7 years ago
Andres Freund	29c94e03c7	Split ExecStoreTuple into ExecStoreHeapTuple and ExecStoreBufferHeapTuple. ... Upcoming changes introduce further types of tuple table slots, in preparation of making table storage pluggable. New storage methods will have different representation of tuples, therefore the slot accessor should refer explicitly to heap tuples. Instead of just renaming the functions, split it into one function that accepts heap tuples not residing in buffers, and one accepting ones in buffers. Previously one function was used for both, but that was a bit awkward already, and splitting will allow us to represent slot types for tuples in buffers and normal memory separately. This is split out from the patch introducing abstract slots, as this largely consists out of mechanical changes. Author: Ashutosh Bapat Reviewed-By: Andres Freund Discussion: https://postgr.es/m/20180220224318.gw4oe5jadhpmcdnm@alap3.anarazel.de	7 years ago
Peter Eisentraut	0d5f05cde0	Allow multi-inserts during COPY into a partitioned table ... CopyFrom allows multi-inserts to be used for non-partitioned tables, but this was disabled for partitioned tables. The reason for this appeared to be that the tuple may not belong to the same partition as the previous tuple did. Not allowing multi-inserts here greatly slowed down imports into partitioned tables. These could take twice as long as a copy to an equivalent non-partitioned table. It seems wise to do something about this, so this change allows the multi-inserts by flushing the so-far inserted tuples to the partition when the next tuple does not belong to the same partition, or when the buffer fills. This improves performance when the next tuple in the stream commonly belongs to the same partition as the previous tuple. In cases where the target partition changes on every tuple, using multi-inserts slightly slows the performance. To get around this we track the average size of the batches that have been inserted and adaptively enable or disable multi-inserts based on the size of the batch. Some testing was done and the regression only seems to exist when the average size of the insert batch is close to 1, so let's just enable multi-inserts when the average size is at least 1.3. More performance testing might reveal a better number for, this, but since the slowdown was only 1-2% it does not seem critical enough to spend too much time calculating it. In any case it may depend on other factors rather than just the size of the batch. Allowing multi-inserts for partitions required a bit of work around the per-tuple memory contexts as we must flush the tuples when the next tuple does not belong the same partition. In which case there is no good time to reset the per-tuple context, as we've already built the new tuple by this time. In order to work around this we maintain two per-tuple contexts and just switch between them every time the partition changes and reset the old one. This does mean that the first of each batch of tuples is not allocated in the same memory context as the others, but that does not matter since we only reset the context once the previous batch has been inserted. Author: David Rowley <david.rowley@2ndquadrant.com> Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>	8 years ago
Heikki Linnakangas	6b387179ba	Fix misc typos, mostly in comments. ... A collection of typos I happened to spot while reading code, as well as grepping for common mistakes. Backpatch to all supported versions, as applicable, to avoid conflicts when backporting other commits in the future.	8 years ago
Amit Kapila	40ca70ebcc	Allow using the updated tuple while moving it to a different partition. ... An update that causes the tuple to be moved to a different partition was missing out on re-constructing the to-be-updated tuple, based on the latest tuple in the update chain. Instead, it's simply deleting the latest tuple and inserting a new tuple in the new partition based on the old tuple. Commit 2f17844104 didn't consider this case, so some of the updates were getting lost. In passing, change the argument order for output parameter in ExecDelete and add some commentary about it. Reported-by: Pavan Deolasee Author: Amit Khandekar, with minor changes by me Reviewed-by: Dilip Kumar, Amit Kapila and Alvaro Herrera Backpatch-through: 11 Discussion: https://postgr.es/m/CAJ3gD9fRbEzDqdeDq1jxqZUb47kJn+tQ7=Bcgjc8quqKsDViKQ@mail.gmail.com	8 years ago
Alvaro Herrera	5b0c7e2f75	Don't needlessly check the partition contraint twice ... Starting with commit f0e44751d7, ExecConstraints was in charge of running the partition constraint; commit 19c47e7c82 modified that so that caller could request to skip that checking depending on some conditions, but that commit and 15ce775faa together introduced a small bug there which caused ExecInsert to request skipping the constraint check but have this not be honored -- in effect doing the check twice. This could have been fixed in a very small patch, but on further analysis of the involved function and its callsites, it turns out to be simpler to give the responsibility of checking the partition constraint fully to the caller, and return ExecConstraints to its original (pre-partitioning) shape where it only checked tuple descriptor-related constraints. Each caller must do partition constraint checking on its own schedule, which is more convenient after commit 2f17844104 anyway. Reported-by: David Rowley Author: David Rowley, Álvaro Herrera Reviewed-by: Amit Langote, Amit Khandekar, Simon Riggs Discussion: https://postgr.es/m/CAKJS1f8w8+awsxgea8wt7_UX8qzOQ=Tm1LD+U1fHqBAkXxkW2w@mail.gmail.com	8 years ago
Heikki Linnakangas	57f06a7611	Fix obsolete comment. ... The 'orig_slot' argument was removed in commit c0a8ae7be3, but that commit forgot to update the comment. Author: Amit Langote Discussion: https://www.postgresql.org/message-id/194ac4bf-7b4a-c887-bf26-bc1a85ea995a@lab.ntt.co.jp	8 years ago
Tom Lane	41c912cad1	Clean up warnings from -Wimplicit-fallthrough. ... Recent gcc can warn about switch-case fall throughs that are not explicitly labeled as intentional. This seems like a good thing, so clean up the warnings exposed thereby by labeling all such cases with comments that gcc will recognize. In files that already had one or more suitable comments, I generally matched the existing style of those. Otherwise I went with /* FALLTHROUGH */, which is one of the spellings approved at the more-restrictive-than-default level -Wimplicit-fallthrough=4. (At the default level you can also spell it /* FALL ?THRU */, and it's not picky about case. What you can't do is include additional text in the same comment, so some existing comments containing versions of this aren't good enough.) Testing with gcc 8.0.1 (Fedora 28's current version), I found that I also had to put explicit "break"s after elog(ERROR) or ereport(ERROR); apparently, for this purpose gcc doesn't recognize that those don't return. That seems like possibly a gcc bug, but it's fine because in most places we did that anyway; so this amounts to a visit from the style police. Discussion: https://postgr.es/m/15083.1525207729@sss.pgh.pa.us	8 years ago
Robert Haas	37a3058bc7	Fix interaction of foreign tuple routing with remote triggers. ... Without these fixes, changes to the inserted tuple made by remote triggers are ignored when building local RETURNING tuples. In the core code, call ExecInitRoutingInfo at a later point from within ExecInitPartitionInfo so that the FDW callback gets invoked after the returning list has been built. But move CheckValidResultRel out of ExecInitRoutingInfo so that it can happen at an earlier stage. In postgres_fdw, refactor assorted deparsing functions to work with the RTE rather than the PlannerInfo, which saves us having to construct a fake PlannerInfo in cases where we don't have a real one. Then, we can pass down a constructed RTE that yields the correct deparse result when no real one exists. Unfortunately, this necessitates a hack that understands how the core code manages RT indexes for update tuple routing, which is ugly, but we don't have a better idea right now. Original report, analysis, and patch by Etsuro Fujita. Heavily refactored by me. Then worked over some more by Amit Langote. Discussion: http://postgr.es/m/5AD4882B.10002@lab.ntt.co.jp	8 years ago
Tom Lane	bdf46af748	Post-feature-freeze pgindent run. ... Discussion: https://postgr.es/m/15719.1523984266@sss.pgh.pa.us	8 years ago
Simon Riggs	08ea7a2291	Revert MERGE patch ... This reverts commits d204ef6377, 83454e3c2b and a few more commits thereafter (complete list at the end) related to MERGE feature. While the feature was fully functional, with sufficient test coverage and necessary documentation, it was felt that some parts of the executor and parse-analyzer can use a different design and it wasn't possible to do that in the available time. So it was decided to revert the patch for PG11 and retry again in the future. Thanks again to all reviewers and bug reporters. List of commits reverted, in reverse chronological order: f1464c5380 Improve parse representation for MERGE ddb4158579 MERGE syntax diagram correction 530e69e59b Allow cpluspluscheck to pass by renaming variable 01b88b4df5 MERGE minor errata 3af7b2b0d4 MERGE fix variable warning in non-assert builds a5d86181ec MERGE INSERT allows only one VALUES clause 4b2d44031f MERGE post-commit review 4923550c20 Tab completion for MERGE aa3faa3c7a WITH support in MERGE 83454e3c2b New files for MERGE d204ef6377 MERGE SQL Command following SQL:2016 Author: Pavan Deolasee Reviewed-by: Michael Paquier	8 years ago
Alvaro Herrera	15a8f8caad	Fix IndexOnlyScan counter for heap fetches in parallel mode ... The HeapFetches counter was using a simple value in IndexOnlyScanState, which fails to propagate values from parallel workers; so the counts are wrong when IndexOnlyScan runs in parallel. Move it to Instrumentation, like all the other counters. While at it, change INSERT ON CONFLICT conflicting tuple counter to use the new ntuples2 instead of nfiltered2, which is a blatant misuse. Discussion: https://postgr.es/m/20180409215851.idwc75ct2bzi6tea@alvherre.pgsql	8 years ago
Andres Freund	f16241bef7	Raise error when affecting tuple moved into different partition. ... When an update moves a row between partitions (supported since 2f17844104), our normal logic for following update chains in READ COMMITTED mode doesn't work anymore. Cross partition updates are modeled as an delete from the old and insert into the new partition. No ctid chain exists across partitions, and there's no convenient space to introduce that link. Not throwing an error in a partitioned context when one would have been thrown without partitioning is obviously problematic. This commit introduces infrastructure to detect when a tuple has been moved, not just plainly deleted. That allows to throw an error when encountering a deletion that's actually a move, while attempting to following a ctid chain. The row deleted as part of a cross partition update is marked by pointing it's t_ctid to an invalid block, instead of self as a normal update would. That was deemed to be the least invasive and most future proof way to represent the knowledge, given how few infomask bits are there to be recycled (there's also some locking issues with using infomask bits). External code following ctid chains should be updated to check for moved tuples. The most likely consequence of not doing so is a missed error. Author: Amul Sul, editorialized by me Reviewed-By: Amit Kapila, Pavan Deolasee, Andres Freund, Robert Haas Discussion: http://postgr.es/m/CAAJ_b95PkwojoYfz0bzXU8OokcTVGzN6vYGCNVUukeUDrnF3dw@mail.gmail.com	8 years ago
Robert Haas	3d956d9562	Allow insert and update tuple routing and COPY for foreign tables. ... Also enable this for postgres_fdw. Etsuro Fujita, based on an earlier patch by Amit Langote. The larger patch series of which this is a part has been reviewed by Amit Langote, David Fetter, Maksim Milyutin, Álvaro Herrera, Stephen Frost, and me. Minor documentation changes to the final version by me. Discussion: http://postgr.es/m/29906a26-da12-8c86-4fb9-d8f88442f2b9@lab.ntt.co.jp	8 years ago
Simon Riggs	4b2d44031f	MERGE post-commit review ... Review comments from Andres Freund * Consolidate code into AfterTriggerGetTransitionTable() * Rename nodeMerge.c to execMerge.c * Rename nodeMerge.h to execMerge.h * Move MERGE handling in ExecInitModifyTable() into a execMerge.c ExecInitMerge() * Move mt_merge_subcommands flags into execMerge.h * Rename opt_and_condition to opt_merge_when_and_condition * Wordsmith various comments Author: Pavan Deolasee Reviewer: Simon Riggs	8 years ago
Simon Riggs	d204ef6377	MERGE SQL Command following SQL:2016 ... MERGE performs actions that modify rows in the target table using a source table or query. MERGE provides a single SQL statement that can conditionally INSERT/UPDATE/DELETE rows a task that would other require multiple PL statements. e.g. MERGE INTO target AS t USING source AS s ON t.tid = s.sid WHEN MATCHED AND t.balance > s.delta THEN UPDATE SET balance = t.balance - s.delta WHEN MATCHED THEN DELETE WHEN NOT MATCHED AND s.delta > 0 THEN INSERT VALUES (s.sid, s.delta) WHEN NOT MATCHED THEN DO NOTHING; MERGE works with regular and partitioned tables, including column and row security enforcement, as well as support for row, statement and transition triggers. MERGE is optimized for OLTP and is parameterizable, though also useful for large scale ETL/ELT. MERGE is not intended to be used in preference to existing single SQL commands for INSERT, UPDATE or DELETE since there is some overhead. MERGE can be used statically from PL/pgSQL. MERGE does not yet support inheritance, write rules, RETURNING clauses, updatable views or foreign tables. MERGE follows SQL Standard per the most recent SQL:2016. Includes full tests and documentation, including full isolation tests to demonstrate the concurrent behavior. This version written from scratch in 2017 by Simon Riggs, using docs and tests originally written in 2009. Later work from Pavan Deolasee has been both complex and deep, leaving the lead author credit now in his hands. Extensive discussion of concurrency from Peter Geoghegan, with thanks for the time and effort contributed. Various issues reported via sqlsmith by Andreas Seltenreich Authors: Pavan Deolasee, Simon Riggs Reviewer: Peter Geoghegan, Amit Langote, Tomas Vondra, Simon Riggs Discussion: https://postgr.es/m/CANP8+jKitBSrB7oTgT9CY2i1ObfOt36z0XMraQc+Xrz8QB0nXA@mail.gmail.com https://postgr.es/m/CAH2-WzkJdBuxj9PO=2QaO9-3h3xGbQPZ34kJH=HukRekwM-GZg@mail.gmail.com	8 years ago
Simon Riggs	7cf8a5c302	Revert "Modified files for MERGE" ... This reverts commit 354f13855e.	8 years ago
Simon Riggs	354f13855e	Modified files for MERGE	8 years ago
Alvaro Herrera	555ee77a96	Handle INSERT .. ON CONFLICT with partitioned tables ... Commit eb7ed3f306 enabled unique constraints on partitioned tables, but one thing that was not working properly is INSERT/ON CONFLICT. This commit introduces a new node keeps state related to the ON CONFLICT clause per partition, and fills it when that partition is about to be used for tuple routing. Author: Amit Langote, Álvaro Herrera Reviewed-by: Etsuro Fujita, Pavan Deolasee Discussion: https://postgr.es/m/20180228004602.cwdyralmg5ejdqkq@alvherre.pgsql	8 years ago
Alvaro Herrera	ee0a1fc84e	Remove unnecessary members from ModifyTableState and ExecInsert ... These values can be obtained from the ModifyTable node which is already a part of both the ModifyTableState and ExecInsert. Author: Álvaro Herrera, Amit Langote Reviewed-by: Peter Geoghegan Discussion: https://postgr.es/m/20180316151303.rml2p5wffn3o6qy6@alvherre.pgsql	8 years ago
Alvaro Herrera	839a8eb2b3	Expand comment a little bit ... The previous commit removed a comment that was a bit more verbose than its replacement.	8 years ago
Alvaro Herrera	6666ee49f4	Fix state reversal after partition tuple routing ... We make some changes to ModifyTableState and the EState it uses whenever we route tuples to partitions; but we weren't restoring properly in all cases, possibly causing crashes when partitions with different tuple descriptors are targeted by tuples inserted in the same command. Refactor some code, creating ExecPrepareTupleRouting, to encapsulate the needed state changing logic, and have it invoked one level above its current place (ie. put it in ExecModifyTable instead of ExecInsert); this makes it all more readable. Add a test case to exercise this. We don't support having views as partitions; and since only views can have INSTEAD OF triggers, there is no point in testing for INSTEAD OF when processing insertions into a partitioned table. Remove code that appears to support this (but which is actually never relevant.) In passing, fix location of some very confusing comments in ModifyTableState. Reported-by: Amit Langote Author: Etsuro Fujita, Amit Langote Discussion: https://postgr/es/m/0473bf5c-57b1-f1f7-3d58-455c2230bc5f@lab.ntt.co.jp	8 years ago
Stephen Frost	97d18ce27d	Fix comment for ExecProcessReturning ... resultRelInfo is the argument for the function, not projectReturning. Author: Etsuro Fujita Discussion: https://postgr.es/m/5AA8E11E.1040609@lab.ntt.co.jp	8 years ago
Robert Haas	edd44738bc	Be lazier about partition tuple routing. ... It's not necessary to fully initialize the executor data structures for partitions to which no tuples are ever routed. Consider, for example, an INSERT statement that inserts only one row: it only cares about the partition to which that one row is routed. The new function ExecInitPartitionInfo performs the initialization in question only when a particular partition is about to receive a tuple. This includes creating, validating, and saving a pointer to the ResultRelInfo, setting up for speculative insertions, translating WCOs and initializing the resulting expressions, translating returning lists and building the appropriate projection information, and setting up a tuple conversion map. One thing that's not deferred is locking the child partitions; that seems desirable but would need more thought. Still, testing shows that this makes single-row inserts significantly faster on a table with many partitions without harming the bulk-insert case. Amit Langote, reviewed by Etsuro Fujita, with a few changes by me Discussion: http://postgr.es/m/8975331d-d961-cbdd-f862-fdd3d97dc2d0@lab.ntt.co.jp	8 years ago
Andres Freund	ad7dbee368	Allow tupleslots to have a fixed tupledesc, use in executor nodes. ... The reason for doing so is that it will allow expression evaluation to optimize based on the underlying tupledesc. In particular it will allow to JIT tuple deforming together with the expression itself. For that expression initialization needs to be moved after the relevant slots are initialized - mostly unproblematic, except in the case of nodeWorktablescan.c. After doing so there's no need for ExecAssignResultType() and ExecAssignResultTypeFromTL() anymore, as all former callers have been converted to create a slot with a fixed descriptor. When creating a slot with a fixed descriptor, tts_values/isnull can be allocated together with the main slot, reducing allocation overhead and increasing cache density a bit. Author: Andres Freund Discussion: https://postgr.es/m/20171206093717.vqdxe5icqttpxs3p@alap3.anarazel.de	8 years ago
Tom Lane	bb415675d8	Add missing "static" markers. ... Per buildfarm.	8 years ago
Robert Haas	945f71db84	Avoid referencing off the end of subplan_partition_offsets. ... Report by buildfarm member skink and Tom Lane. Analysis by me. Patch by Amit Khandekar. Discussion: http://postgr.es/m/CAJ3gD9fVA1iXQYhfqHP5n_TEd4U9=V8TL_cc-oKRnRmxgdvJrQ@mail.gmail.com	8 years ago
Robert Haas	2f17844104	Allow UPDATE to move rows between partitions. ... When an UPDATE causes a row to no longer match the partition constraint, try to move it to a different partition where it does match the partition constraint. In essence, the UPDATE is split into a DELETE from the old partition and an INSERT into the new one. This can lead to surprising behavior in concurrency scenarios because EvalPlanQual rechecks won't work as they normally did; the known problems are documented. (There is a pending patch to improve the situation further, but it needs more review.) Amit Khandekar, reviewed and tested by Amit Langote, David Rowley, Rajkumar Raghuwanshi, Dilip Kumar, Amul Sul, Thomas Munro, Álvaro Herrera, Amit Kapila, and me. A few final revisions by me. Discussion: http://postgr.es/m/CAJ3gD9do9o2ccQ7j7+tSgiE1REY65XRiMb=yJO3u3QhyP8EEPQ@mail.gmail.com	8 years ago