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2018-12-10Add stack depth checks to key recursive functions in backend/nodes/*.c.Tom Lane
Although copyfuncs.c has a check_stack_depth call in its recursion, equalfuncs.c, outfuncs.c, and readfuncs.c lacked one. This seems unwise. Likewise fix planstate_tree_walker(), in branches where that exists. Discussion: https://postgr.es/m/30253.1544286631@sss.pgh.pa.us
2018-11-08Revise attribute handling code on partition creationAlvaro Herrera
The original code to propagate NOT NULL and default expressions specified when creating a partition was mostly copy-pasted from typed-tables creation, but not being a great match it contained some duplicity, inefficiency and bugs. This commit fixes the bug that NOT NULL constraints declared in the parent table would not be honored in the partition. One reported issue that is not fixed is that a DEFAULT declared in the child is not used when inserting through the parent. That would amount to a behavioral change that's better not back-patched. This rewrite makes the code simpler: 1. instead of checking for duplicate column names in its own block, reuse the original one that already did that; 2. instead of concatenating the list of columns from parent and the one declared in the partition and scanning the result to (incorrectly) propagate defaults and not-null constraints, just scan the latter searching the former for a match, and merging sensibly. This works because we know the list in the parent is already correct and there can only be one parent. This rewrite makes ColumnDef->is_from_parent unused, so it's removed on branch master; on released branches, it's kept as an unused field in order not to cause ABI incompatibilities. This commit also adds a test case for creating partitions with collations mismatching that on the parent table, something that is closely related to the code being patched. No code change is introduced though, since that'd be a behavior change that could break some (broken) working applications. Amit Langote wrote a less invasive fix for the original NOT NULL/defaults bug, but while I kept the tests he added, I ended up not using his original code. Ashutosh Bapat reviewed Amit's fix. Amit reviewed mine. Author: Álvaro Herrera, Amit Langote Reviewed-by: Ashutosh Bapat, Amit Langote Reported-by: Jürgen Strobel (bug #15212) Discussion: https://postgr.es/m/152746742177.1291.9847032632907407358@wrigleys.postgresql.org
2018-10-12Correct attach/detach logic for FKs in partitionsAlvaro Herrera
There was no code to handle foreign key constraints on partitioned tables in the case of ALTER TABLE DETACH; and if you happened to ATTACH a partition that already had an equivalent constraint, that one was ignored and a new constraint was created. Adding this to the fact that foreign key cloning reuses the constraint name on the partition instead of generating a new name (as it probably should, to cater to SQL standard rules about constraint naming within schemas), the result was a pretty poor user experience -- the most visible failure was that just detaching a partition and re-attaching it failed with an error such as ERROR: duplicate key value violates unique constraint "pg_constraint_conrelid_contypid_conname_index" DETAIL: Key (conrelid, contypid, conname)=(26702, 0, test_result_asset_id_fkey) already exists. because it would try to create an identically-named constraint in the partition. To make matters worse, if you tried to drop the constraint in the now-independent partition, that would fail because the constraint was still seen as dependent on the constraint in its former parent partitioned table: ERROR: cannot drop inherited constraint "test_result_asset_id_fkey" of relation "test_result_cbsystem_0001_0050_monthly_2018_09" This fix attacks the problem from two angles: first, when the partition is detached, the constraint is also marked as independent, so the drop now works. Second, when the partition is re-attached, we scan existing constraints searching for one matching the FK in the parent, and if one exists, we link that one to the parent constraint. So we don't end up with a duplicate -- and better yet, we don't need to scan the referenced table to verify that the constraint holds. To implement this I made a small change to previously planner-only struct ForeignKeyCacheInfo to contain the constraint OID; also relcache now maintains the list of FKs for partitioned tables too. Backpatch to 11. Reported-by: Michael Vitale (bug #15425) Discussion: https://postgr.es/m/15425-2dbc9d2aa999f816@postgresql.org
2018-10-07Remove some unnecessary fields from Plan trees.Tom Lane
In the wake of commit f2343653f, we no longer need some fields that were used before to control executor lock acquisitions: * PlannedStmt.nonleafResultRelations can go away entirely. * partitioned_rels can go away from Append, MergeAppend, and ModifyTable. However, ModifyTable still needs to know the RT index of the partition root table if any, which was formerly kept in the first entry of that list. Add a new field "rootRelation" to remember that. rootRelation is partly redundant with nominalRelation, in that if it's set it will have the same value as nominalRelation. However, the latter field has a different purpose so it seems best to keep them distinct. Amit Langote, reviewed by David Rowley and Jesper Pedersen, and whacked around a bit more by me Discussion: https://postgr.es/m/468c85d9-540e-66a2-1dde-fec2b741e688@lab.ntt.co.jp
2018-10-04Centralize executor's opening/closing of Relations for rangetable entries.Tom Lane
Create an array estate->es_relations[] paralleling the es_range_table, and store references to Relations (relcache entries) there, so that any given RT entry is opened and closed just once per executor run. Scan nodes typically still call ExecOpenScanRelation, but ExecCloseScanRelation is no more; relation closing is now done centrally in ExecEndPlan. This is slightly more complex than one would expect because of the interactions with relcache references held in ResultRelInfo nodes. The general convention is now that ResultRelInfo->ri_RelationDesc does not represent a separate relcache reference and so does not need to be explicitly closed; but there is an exception for ResultRelInfos in the es_trig_target_relations list, which are manufactured by ExecGetTriggerResultRel and have to be cleaned up by ExecCleanUpTriggerState. (That much was true all along, but these ResultRelInfos are now more different from others than they used to be.) To allow the partition pruning logic to make use of es_relations[] rather than having its own relcache references, adjust PartitionedRelPruneInfo to store an RT index rather than a relation OID. Amit Langote, reviewed by David Rowley and Jesper Pedersen, some mods by me Discussion: https://postgr.es/m/468c85d9-540e-66a2-1dde-fec2b741e688@lab.ntt.co.jp
2018-09-30Create an RTE field to record the query's lock mode for each relation.Tom Lane
Add RangeTblEntry.rellockmode, which records the appropriate lock mode for each RTE_RELATION rangetable entry (either AccessShareLock, RowShareLock, or RowExclusiveLock depending on the RTE's role in the query). This patch creates the field and makes all creators of RTE nodes fill it in reasonably, but for the moment nothing much is done with it. The plan is to replace assorted post-parser logic that re-determines the right lockmode to use with simple uses of rte->rellockmode. For now, just add Asserts in each of those places that the rellockmode matches what they are computing today. (In some cases the match isn't perfect, so the Asserts are weaker than you might expect; but this seems OK, as per discussion.) This passes check-world for me, but it seems worth pushing in this state to see if the buildfarm finds any problems in cases I failed to test. catversion bump due to change of stored rules. Amit Langote, reviewed by David Rowley and Jesper Pedersen, and whacked around a bit more by me Discussion: https://postgr.es/m/468c85d9-540e-66a2-1dde-fec2b741e688@lab.ntt.co.jp
2018-09-18Fix some minor issues exposed by outfuncs/readfuncs testing.Tom Lane
A test patch to pass parse and plan trees through outfuncs + readfuncs exposed several issues that need to be fixed to get clean matches: Query.withCheckOptions failed to get copied; it's intentionally ignored by outfuncs/readfuncs on the grounds that it'd always be NIL anyway in stored rules. This seems less than future-proof, and it's not even saving very much, so just undo the decision and treat the field like all others. Several places that convert a view RTE into a subquery RTE, or similar manipulations, failed to clear out fields that were specific to the original RTE type and should be zero in a subquery RTE. Since readfuncs.c will leave such fields as zero, equalfuncs.c thinks the nodes are different leading to a reported mismatch. It seems like a good idea to clear out the no-longer-needed fields, even though in principle nothing should look at them; the node ought to be indistinguishable from how it would look if we'd built a new node instead of scribbling on the old one. BuildOnConflictExcludedTargetlist randomly set the resname of some TargetEntries to "" not NULL. outfuncs/readfuncs don't distinguish those cases, and so the string will read back in as NULL ... but equalfuncs.c does distinguish. Perhaps we ought to try to make things more consistent in this area --- but it's just useless extra code space for BuildOnConflictExcludedTargetlist to not use NULL here, so I fixed it for now by making it do that. catversion bumped because the change in handling of Query.withCheckOptions affects stored rules. Discussion: https://postgr.es/m/17114.1537138992@sss.pgh.pa.us
2018-09-16Add outfuncs.c support for RawStmt nodes.Tom Lane
I noticed while poking at a report from Andrey Lepikhov that the recent addition of RawStmt nodes at the top of raw parse trees makes it impossible to print any raw parse trees whatsoever, because outfuncs.c doesn't know RawStmt and hence fails to descend into it. While we generally lack outfuncs.c support for utility statements, there is reasonably complete support for what you can find in a raw SELECT statement. It was not my intention to make that all dead code ... so let's add support for RawStmt. Back-patch to v10 where RawStmt appeared.
2018-08-31Disable support for partitionwise joins in problematic cases.Etsuro Fujita
Commit f49842d, which added support for partitionwise joins, built the child's tlist by applying adjust_appendrel_attrs() to the parent's. So in the case where the parent's included a whole-row Var for the parent, the child's contained a ConvertRowtypeExpr. To cope with that, that commit added code to the planner, such as setrefs.c, but some code paths still assumed that the tlist for a scan (or join) rel would only include Vars and PlaceHolderVars, which was true before that commit, causing errors: * When creating an explicit sort node for an input path for a mergejoin path for a child join, prepare_sort_from_pathkeys() threw the 'could not find pathkey item to sort' error. * When deparsing a relation participating in a pushed down child join as a subquery in contrib/postgres_fdw, get_relation_column_alias_ids() threw the 'unexpected expression in subquery output' error. * When performing set_plan_references() on a local join plan generated by contrib/postgres_fdw for EvalPlanQual support for a pushed down child join, fix_join_expr() threw the 'variable not found in subplan target lists' error. To fix these, two approaches have been proposed: one by Ashutosh Bapat and one by me. While the former keeps building the child's tlist with a ConvertRowtypeExpr, the latter builds it with a whole-row Var for the child not to violate the planner assumption, and tries to fix it up later, But both approaches need more work, so refuse to generate partitionwise join paths when whole-row Vars are involved, instead. We don't need to handle ConvertRowtypeExprs in the child's tlists for now, so this commit also removes the changes to the planner. Previously, partitionwise join computed attr_needed data for each child separately, and built the child join's tlist using that data, which also required an extra step for adding PlaceHolderVars to that tlist, but it would be more efficient to build it from the parent join's tlist through the adjust_appendrel_attrs() transformation. So this commit builds that list that way, and simplifies build_joinrel_tlist() and placeholder.c as well as part of set_append_rel_size() to basically what they were before partitionwise join went in. Back-patch to PG11 where partitionwise join was introduced. Report by Rajkumar Raghuwanshi. Analysis by Ashutosh Bapat, who also provided some of regression tests. Patch by me, reviewed by Robert Haas. Discussion: https://postgr.es/m/CAKcux6ktu-8tefLWtQuuZBYFaZA83vUzuRd7c1YHC-yEWyYFpg@mail.gmail.com
2018-08-01Fix run-time partition pruning for appends with multiple source rels.Tom Lane
The previous coding here supposed that if run-time partitioning applied to a particular Append/MergeAppend plan, then all child plans of that node must be members of a single partitioning hierarchy. This is totally wrong, since an Append could be formed from a UNION ALL: we could have multiple hierarchies sharing the same Append, or child plans that aren't part of any hierarchy. To fix, restructure the related plan-time and execution-time data structures so that we can have a separate list or array for each partitioning hierarchy. Also track subplans that are not part of any hierarchy, and make sure they don't get pruned. Per reports from Phil Florent and others. Back-patch to v11, since the bug originated there. David Rowley, with a lot of cosmetic adjustments by me; thanks also to Amit Langote for review. Discussion: https://postgr.es/m/HE1PR03MB17068BB27404C90B5B788BCABA7B0@HE1PR03MB1706.eurprd03.prod.outlook.com
2018-07-19Expand run-time partition pruning to work with MergeAppendHeikki Linnakangas
This expands the support for the run-time partition pruning which was added for Append in 499be013de to also allow unneeded subnodes of a MergeAppend to be removed. Author: David Rowley Discussion: https://www.postgresql.org/message-id/CAKJS1f_F_V8D7Wu-HVdnH7zCUxhoGK8XhLLtd%3DCu85qDZzXrgg%40mail.gmail.com
2018-07-11Fix bugs with degenerate window ORDER BY clauses in GROUPS/RANGE mode.Tom Lane
nodeWindowAgg.c failed to cope with the possibility that no ordering columns are defined in the window frame for GROUPS mode or RANGE OFFSET mode, leading to assertion failures or odd errors, as reported by Masahiko Sawada and Lukas Eder. In RANGE OFFSET mode, an ordering column is really required, so add an Assert about that. In GROUPS mode, the code would work, except that the node initialization code wasn't in sync with the execution code about when to set up tuplestore read pointers and spare slots. Fix the latter for consistency's sake (even though I think the changes described below make the out-of-sync cases unreachable for now). Per SQL spec, a single ordering column is required for RANGE OFFSET mode, and at least one ordering column is required for GROUPS mode. The parser enforced the former but not the latter; add a check for that. We were able to reach the no-ordering-column cases even with fully spec compliant queries, though, because the planner would drop partitioning and ordering columns from the generated plan if they were redundant with earlier columns according to the redundant-pathkey logic, for instance "PARTITION BY x ORDER BY y" in the presence of a "WHERE x=y" qual. While in principle that's an optimization that could save some pointless comparisons at runtime, it seems unlikely to be meaningful in the real world. I think this behavior was not so much an intentional optimization as a side-effect of an ancient decision to construct the plan node's ordering-column info by reverse-engineering the PathKeys of the input path. If we give up redundant-column removal then it takes very little code to generate the plan node info directly from the WindowClause, ensuring that we have the expected number of ordering columns in all cases. (If anyone does complain about this, the planner could perhaps be taught to remove redundant columns only when it's safe to do so, ie *not* in RANGE OFFSET mode. But I doubt anyone ever will.) With these changes, the WindowAggPath.winpathkeys field is not used for anything anymore, so remove it. The test cases added here are not actually very interesting given the removal of the redundant-column-removal logic, but they would represent important corner cases if anyone ever tries to put that back. Tom Lane and Masahiko Sawada. Back-patch to v11 where RANGE OFFSET and GROUPS modes were added. Discussion: https://postgr.es/m/CAD21AoDrWqycq-w_+Bx1cjc+YUhZ11XTj9rfxNiNDojjBx8Fjw@mail.gmail.com Discussion: https://postgr.es/m/153086788677.17476.8002640580496698831@wrigleys.postgresql.org
2018-06-10Assorted cosmetic cleanup of run-time-partition-pruning code.Tom Lane
Use "subplan" rather than "subnode" to refer to the child plans of a partitioning Append; this seems a bit more specific and hence clearer. Improve assorted comments. No non-cosmetic changes. David Rowley and Tom Lane Discussion: https://postgr.es/m/CAFj8pRBjrufA3ocDm8o4LPGNye9Y+pm1b9kCwode4X04CULG3g@mail.gmail.com
2018-06-10Relocate partition pruning structs to a saner place.Tom Lane
These struct definitions were originally dropped into primnodes.h, which is a poor choice since that's mainly intended for primitive expression node types; these are not in that category. What they are is auxiliary info in Plan trees, so move them to plannodes.h. For consistency, also relocate some related code that was apparently placed with the aid of a dartboard. There's no interesting code changes in this commit, just reshuffling. David Rowley and Tom Lane Discussion: https://postgr.es/m/CAFj8pRBjrufA3ocDm8o4LPGNye9Y+pm1b9kCwode4X04CULG3g@mail.gmail.com
2018-06-10Improve run-time partition pruning to handle any stable expression.Tom Lane
The initial coding of the run-time-pruning feature only coped with cases where the partition key(s) are compared to Params. That is a bit silly; we can allow it to work with any non-Var-containing stable expression, as long as we take special care with expressions containing PARAM_EXEC Params. The code is hardly any longer this way, and it's considerably clearer (IMO at least). Per gripe from Pavel Stehule. David Rowley, whacked around a bit by me Discussion: https://postgr.es/m/CAFj8pRBjrufA3ocDm8o4LPGNye9Y+pm1b9kCwode4X04CULG3g@mail.gmail.com
2018-05-31Reconcile nodes/*funcs.c with PostgreSQL 11 work.Noah Misch
This covers new fields in two outfuncs.c functions having no readfuncs.c counterpart. Thus, this changes only debugging output.
2018-04-28Fix incorrect field type for PlannedStmt.jitFlags in outfuncs/readfuncs.Tom Lane
This field was a bool at one point, but now it's an int. Spotted by Hari Babu; trivial patch is by Ashutosh Bapat. Discussion: https://postgr.es/m/CAJrrPGedKiFE2fqntSauUfhapCksOJzam+QtHfSgx86LhXLeOQ@mail.gmail.com
2018-04-23Add GUC enable_partition_pruningAlvaro Herrera
This controls both plan-time and execution-time new-style partition pruning. While finer-grain control is possible (maybe using an enum GUC instead of boolean), there doesn't seem to be much need for that. This new parameter controls partition pruning for all queries: trivially, SELECT queries that affect partitioned tables are naturally under its control since they are using the new technology. However, while UPDATE/DELETE queries do not use the new code, we make the new GUC control their behavior also (stealing control from constraint_exclusion), because it is more natural, and it leads to a more natural transition to the future in which those queries will also use the new pruning code. Constraint exclusion still controls pruning for regular inheritance situations (those not involving partitioned tables). Author: David Rowley Review: Amit Langote, Ashutosh Bapat, Justin Pryzby, David G. Johnston Discussion: https://postgr.es/m/CAKJS1f_0HwsxJG9m+nzU+CizxSdGtfe6iF_ykPYBiYft302DCw@mail.gmail.com
2018-04-12Revert MERGE patchSimon Riggs
This reverts commits d204ef63776b8a00ca220adec23979091564e465, 83454e3c2b28141c0db01c7d2027e01040df5249 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
2018-04-07Support partition pruning at execution timeAlvaro Herrera
Existing partition pruning is only able to work at plan time, for query quals that appear in the parsed query. This is good but limiting, as there can be parameters that appear later that can be usefully used to further prune partitions. This commit adds support for pruning subnodes of Append which cannot possibly contain any matching tuples, during execution, by evaluating Params to determine the minimum set of subnodes that can possibly match. We support more than just simple Params in WHERE clauses. Support additionally includes: 1. Parameterized Nested Loop Joins: The parameter from the outer side of the join can be used to determine the minimum set of inner side partitions to scan. 2. Initplans: Once an initplan has been executed we can then determine which partitions match the value from the initplan. Partition pruning is performed in two ways. When Params external to the plan are found to match the partition key we attempt to prune away unneeded Append subplans during the initialization of the executor. This allows us to bypass the initialization of non-matching subplans meaning they won't appear in the EXPLAIN or EXPLAIN ANALYZE output. For parameters whose value is only known during the actual execution then the pruning of these subplans must wait. Subplans which are eliminated during this stage of pruning are still visible in the EXPLAIN output. In order to determine if pruning has actually taken place, the EXPLAIN ANALYZE must be viewed. If a certain Append subplan was never executed due to the elimination of the partition then the execution timing area will state "(never executed)". Whereas, if, for example in the case of parameterized nested loops, the number of loops stated in the EXPLAIN ANALYZE output for certain subplans may appear lower than others due to the subplan having been scanned fewer times. This is due to the list of matching subnodes having to be evaluated whenever a parameter which was found to match the partition key changes. This commit required some additional infrastructure that permits the building of a data structure which is able to perform the translation of the matching partition IDs, as returned by get_matching_partitions, into the list index of a subpaths list, as exist in node types such as Append, MergeAppend and ModifyTable. This allows us to translate a list of clauses into a Bitmapset of all the subpath indexes which must be included to satisfy the clause list. Author: David Rowley, based on an earlier effort by Beena Emerson Reviewers: Amit Langote, Robert Haas, Amul Sul, Rajkumar Raghuwanshi, Jesper Pedersen Discussion: https://postgr.es/m/CAOG9ApE16ac-_VVZVvv0gePSgkg_BwYEV1NBqZFqDR2bBE0X0A@mail.gmail.com
2018-04-07Indexes with INCLUDE columns and their support in B-treeTeodor Sigaev
This patch introduces INCLUDE clause to index definition. This clause specifies a list of columns which will be included as a non-key part in the index. The INCLUDE columns exist solely to allow more queries to benefit from index-only scans. Also, such columns don't need to have appropriate operator classes. Expressions are not supported as INCLUDE columns since they cannot be used in index-only scans. Index access methods supporting INCLUDE are indicated by amcaninclude flag in IndexAmRoutine. For now, only B-tree indexes support INCLUDE clause. In B-tree indexes INCLUDE columns are truncated from pivot index tuples (tuples located in non-leaf pages and high keys). Therefore, B-tree indexes now might have variable number of attributes. This patch also provides generic facility to support that: pivot tuples contain number of their attributes in t_tid.ip_posid. Free 13th bit of t_info is used for indicating that. This facility will simplify further support of index suffix truncation. The changes of above are backward-compatible, pg_upgrade doesn't need special handling of B-tree indexes for that. Bump catalog version Author: Anastasia Lubennikova with contribition by Alexander Korotkov and me Reviewed by: Peter Geoghegan, Tomas Vondra, Antonin Houska, Jeff Janes, David Rowley, Alexander Korotkov Discussion: https://www.postgresql.org/message-id/flat/56168952.4010101@postgrespro.ru
2018-04-06Faster partition pruningAlvaro Herrera
Add a new module backend/partitioning/partprune.c, implementing a more sophisticated algorithm for partition pruning. The new module uses each partition's "boundinfo" for pruning instead of constraint exclusion, based on an idea proposed by Robert Haas of a "pruning program": a list of steps generated from the query quals which are run iteratively to obtain a list of partitions that must be scanned in order to satisfy those quals. At present, this targets planner-time partition pruning, but there exist further patches to apply partition pruning at execution time as well. This commit also moves some definitions from include/catalog/partition.h to a new file include/partitioning/partbounds.h, in an attempt to rationalize partitioning related code. Authors: Amit Langote, David Rowley, Dilip Kumar Reviewers: Robert Haas, Kyotaro Horiguchi, Ashutosh Bapat, Jesper Pedersen. Discussion: https://postgr.es/m/098b9c71-1915-1a2a-8d52-1a7a50ce79e8@lab.ntt.co.jp
2018-04-06Improve parse representation for MERGESimon Riggs
Separation of parser data structures from executor, as requested by Tom Lane. Further improvements possible. While there, implement error for multiple VALUES clauses via parser to allow line number of error, as requested by Andres Freund. Author: Pavan Deolasee Discussion: https://www.postgresql.org/message-id/CABOikdPpqjectFchg0FyTOpsGXyPoqwgC==OLKWuxgBOsrDDZw@mail.gmail.com
2018-04-03MERGE SQL Command following SQL:2016Simon Riggs
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
2018-04-02Revert "Modified files for MERGE"Simon Riggs
This reverts commit 354f13855e6381d288dfaa52bcd4f2cb0fd4a5eb.
2018-04-02Modified files for MERGESimon Riggs
2018-03-22Basic planner and executor integration for JIT.Andres Freund
This adds simple cost based plan time decision about whether JIT should be performed. jit_above_cost, jit_optimize_above_cost are compared with the total cost of a plan, and if the cost is above them JIT is performed / optimization is performed respectively. For that PlannedStmt and EState have a jitFlags (es_jit_flags) field that stores information about what JIT operations should be performed. EState now also has a new es_jit field, which can store a JitContext. When there are no errors the context is released in standard_ExecutorEnd(). It is likely that the default values for jit_[optimize_]above_cost will need to be adapted further, but in my test these values seem to work reasonably. Author: Andres Freund, with feedback by Peter Eisentraut Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
2018-03-13Change internal integer representation of Value nodePeter Eisentraut
A Value node would store an integer as a long. This causes needless portability risks, as long can be of varying sizes. Change it to use int instead. All code using this was already careful to only store 32-bit values anyway. Reviewed-by: Michael Paquier <michael@paquier.xyz>
2018-03-05Clone extended stats in CREATE TABLE (LIKE INCLUDING ALL)Alvaro Herrera
The LIKE INCLUDING ALL clause to CREATE TABLE intuitively indicates cloning of extended statistics on the source table, but it failed to do so. Patch it up so that it does. Also include an INCLUDING STATISTICS option to the LIKE clause, so that the behavior can be requested individually, or excluded individually. While at it, reorder the INCLUDING options, both in code and in docs, in alphabetical order which makes more sense than feature-implementation order that was previously used. Backpatch this to Postgres 10, where extended statistics were introduced, because this is seen as an oversight in a fresh feature which is better to get consistent from the get-go instead of changing only in pg11. In pg11, comments on statistics objects are cloned too. In pg10 they are not, because I (Álvaro) was too coward to change the parse node as required to support it. Also, in pg10 I chose not to renumber the parser symbols for the various INCLUDING options in LIKE, for the same reason. Any corresponding user-visible changes (docs) are backpatched, though. Reported-by: Stephen Froehlich Author: David Rowley Reviewed-by: Álvaro Herrera, Tomas Vondra Discussion: https://postgr.es/m/CY1PR0601MB1927315B45667A1B679D0FD5E5EF0@CY1PR0601MB1927.namprd06.prod.outlook.com
2018-02-07Support all SQL:2011 options for window frame clauses.Tom Lane
This patch adds the ability to use "RANGE offset PRECEDING/FOLLOWING" frame boundaries in window functions. We'd punted on that back in the original patch to add window functions, because it was not clear how to do it in a reasonably data-type-extensible fashion. That problem is resolved here by adding the ability for btree operator classes to provide an "in_range" support function that defines how to add or subtract the RANGE offset value. Factoring it this way also allows the operator class to avoid overflow problems near the ends of the datatype's range, if it wishes to expend effort on that. (In the committed patch, the integer opclasses handle that issue, but it did not seem worth the trouble to avoid overflow failures for datetime types.) The patch includes in_range support for the integer_ops opfamily (int2/int4/int8) as well as the standard datetime types. Support for other numeric types has been requested, but that seems like suitable material for a follow-on patch. In addition, the patch adds GROUPS mode which counts the offset in ORDER-BY peer groups rather than rows, and it adds the frame_exclusion options specified by SQL:2011. As far as I can see, we are now fully up to spec on window framing options. Existing behaviors remain unchanged, except that I changed the errcode for a couple of existing error reports to meet the SQL spec's expectation that negative "offset" values should be reported as SQLSTATE 22013. Internally and in relevant parts of the documentation, we now consistently use the terminology "offset PRECEDING/FOLLOWING" rather than "value PRECEDING/FOLLOWING", since the term "value" is confusingly vague. Oliver Ford, reviewed and whacked around some by me Discussion: https://postgr.es/m/CAGMVOdu9sivPAxbNN0X+q19Sfv9edEPv=HibOJhB14TJv_RCQg@mail.gmail.com
2018-02-02Fix application of identity values in some casesPeter Eisentraut
Investigation of 2d2d06b7e27e3177d5bef0061801c75946871db3 revealed that identity values were not applied in some further cases, including logical replication subscribers, VALUES RTEs, and ALTER TABLE ... ADD COLUMN. To fix all that, apply the identity column expression in build_column_default() instead of repeating the same logic at each call site. For ALTER TABLE ... ADD COLUMN ... IDENTITY, the previous coding completely ignored that existing rows for the new column should have values filled in from the identity sequence. The coding using build_column_default() fails for this because the sequence ownership isn't registered until after ALTER TABLE, and we can't do it before because we don't have the column in the catalog yet. So we specially remember in ColumnDef the sequence name that we decided on and build a custom NextValueExpr using that. Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
2018-01-19Allow UPDATE to move rows between partitions.Robert Haas
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
2018-01-19Local partitioned indexesAlvaro Herrera
When CREATE INDEX is run on a partitioned table, create catalog entries for an index on the partitioned table (which is just a placeholder since the table proper has no data of its own), and recurse to create actual indexes on the existing partitions; create them in future partitions also. As a convenience gadget, if the new index definition matches some existing index in partitions, these are picked up and used instead of creating new ones. Whichever way these indexes come about, they become attached to the index on the parent table and are dropped alongside it, and cannot be dropped on isolation unless they are detached first. To support pg_dump'ing these indexes, add commands CREATE INDEX ON ONLY <table> (which creates the index on the parent partitioned table, without recursing) and ALTER INDEX ATTACH PARTITION (which is used after the indexes have been created individually on each partition, to attach them to the parent index). These reconstruct prior database state exactly. Reviewed-by: (in alphabetical order) Peter Eisentraut, Robert Haas, Amit Langote, Jesper Pedersen, Simon Riggs, David Rowley Discussion: https://postgr.es/m/20171113170646.gzweigyrgg6pwsg4@alvherre.pgsql
2018-01-02Update copyright for 2018Bruce Momjian
Backpatch-through: certain files through 9.3
2017-12-21Add parallel-aware hash joins.Andres Freund
Introduce parallel-aware hash joins that appear in EXPLAIN plans as Parallel Hash Join with Parallel Hash. While hash joins could already appear in parallel queries, they were previously always parallel-oblivious and had a partial subplan only on the outer side, meaning that the work of the inner subplan was duplicated in every worker. After this commit, the planner will consider using a partial subplan on the inner side too, using the Parallel Hash node to divide the work over the available CPU cores and combine its results in shared memory. If the join needs to be split into multiple batches in order to respect work_mem, then workers process different batches as much as possible and then work together on the remaining batches. The advantages of a parallel-aware hash join over a parallel-oblivious hash join used in a parallel query are that it: * avoids wasting memory on duplicated hash tables * avoids wasting disk space on duplicated batch files * divides the work of building the hash table over the CPUs One disadvantage is that there is some communication between the participating CPUs which might outweigh the benefits of parallelism in the case of small hash tables. This is avoided by the planner's existing reluctance to supply partial plans for small scans, but it may be necessary to estimate synchronization costs in future if that situation changes. Another is that outer batch 0 must be written to disk if multiple batches are required. A potential future advantage of parallel-aware hash joins is that right and full outer joins could be supported, since there is a single set of matched bits for each hashtable, but that is not yet implemented. A new GUC enable_parallel_hash is defined to control the feature, defaulting to on. Author: Thomas Munro Reviewed-By: Andres Freund, Robert Haas Tested-By: Rafia Sabih, Prabhat Sahu Discussion: https://postgr.es/m/CAEepm=2W=cOkiZxcg6qiFQP-dHUe09aqTrEMM7yJDrHMhDv_RA@mail.gmail.com https://postgr.es/m/CAEepm=37HKyJ4U6XOLi=JgfSHM3o6B-GaeO-6hkOmneTDkH+Uw@mail.gmail.com
2017-12-05Support Parallel Append plan nodes.Robert Haas
When we create an Append node, we can spread out the workers over the subplans instead of piling on to each subplan one at a time, which should typically be a bit more efficient, both because the startup cost of any plan executed entirely by one worker is paid only once and also because of reduced contention. We can also construct Append plans using a mix of partial and non-partial subplans, which may allow for parallelism in places that otherwise couldn't support it. Unfortunately, this patch doesn't handle the important case of parallelizing UNION ALL by running each branch in a separate worker; the executor infrastructure is added here, but more planner work is needed. Amit Khandekar, Robert Haas, Amul Sul, reviewed and tested by Ashutosh Bapat, Amit Langote, Rafia Sabih, Amit Kapila, and Rajkumar Raghuwanshi. Discussion: http://postgr.es/m/CAJ3gD9dy0K_E8r727heqXoBmWZ83HwLFwdcaSSmBQ1+S+vRuUQ@mail.gmail.com
2017-11-16Pass InitPlan values to workers via Gather (Merge).Robert Haas
If a PARAM_EXEC parameter is used below a Gather (Merge) but the InitPlan that computes it is attached to or above the Gather (Merge), force the value to be computed before starting parallelism and pass it down to all workers. This allows us to use parallelism in cases where it previously would have had to be rejected as unsafe. We do - in this case - lose the optimization that the value is only computed if it's actually used. An alternative strategy would be to have the first worker that needs the value compute it, but one downside of that approach is that we'd then need to select a parallel-safe path to compute the parameter value; it couldn't for example contain a Gather (Merge) node. At some point in the future, we might want to consider both approaches. Independent of that consideration, there is a great deal more work that could be done to make more kinds of PARAM_EXEC parameters parallel-safe. This infrastructure could be used to allow a Gather (Merge) on the inner side of a nested loop (although that's not a very appealing plan) and cases where the InitPlan is attached below the Gather (Merge) could be addressed as well using various techniques. But this is a good start. Amit Kapila, reviewed and revised by me. Reviewing and testing from Kuntal Ghosh, Haribabu Kommi, and Tushar Ahuja. Discussion: http://postgr.es/m/CAA4eK1LV0Y1AUV4cUCdC+sYOx0Z0-8NAJ2Pd9=UKsbQ5Sr7+JQ@mail.gmail.com
2017-11-13Track in the plan the types associated with PARAM_EXEC parameters.Robert Haas
Up until now, we only tracked the number of parameters, which was sufficient to allocate an array of Datums of the appropriate size, but not sufficient to, for example, know how to serialize a Datum stored in one of those slots. An upcoming patch wants to do that, so add this tracking to make it possible. Patch by me, reviewed by Tom Lane and Amit Kapila. Discussion: http://postgr.es/m/CA+TgmoYqpxDKn8koHdW8BEKk8FMUL0=e8m2Qe=M+r0UBjr3tuQ@mail.gmail.com
2017-11-09Add hash partitioning.Robert Haas
Hash partitioning is useful when you want to partition a growing data set evenly. This can be useful to keep table sizes reasonable, which makes maintenance operations such as VACUUM faster, or to enable partition-wise join. At present, we still depend on constraint exclusion for partitioning pruning, and the shape of the partition constraints for hash partitioning is such that that doesn't work. Work is underway to fix that, which should both improve performance and make partitioning pruning work with hash partitioning. Amul Sul, reviewed and tested by Dilip Kumar, Ashutosh Bapat, Yugo Nagata, Rajkumar Raghuwanshi, Jesper Pedersen, and by me. A few final tweaks also by me. Discussion: http://postgr.es/m/CAAJ_b96fhpJAP=ALbETmeLk1Uni_GFZD938zgenhF49qgDTjaQ@mail.gmail.com
2017-10-11pg_stat_statements: Widen query IDs from 32 bits to 64 bits.Robert Haas
This takes advantage of the infrastructure introduced by commit 81c5e46c490e2426db243eada186995da5bb0ba7 to greatly reduce the likelihood that two different queries will end up with the same query ID. It's still possible, of course, but whereas before it the chances of a collision reached 25% around 50,000 queries, it will now take more than 3 billion queries. Backward incompatibility: Because the type exposed at the SQL level is int8, users may now see negative query IDs in the pg_stat_statements view (and also, query IDs more than 4 billion, which was the old limit). Patch by me, reviewed by Michael Paquier and Peter Geoghegan. Discussion: http://postgr.es/m/CA+TgmobG_Kp4cBKFmsznUAaM1GWW6hhRNiZC0KjRMOOeYnz5Yw@mail.gmail.com
2017-09-30Support arrays over domains.Tom Lane
Allowing arrays with a domain type as their element type was left un-done in the original domain patch, but not for any very good reason. This omission leads to such surprising results as array_agg() not working on a domain column, because the parser can't identify a suitable output type for the polymorphic aggregate. In order to fix this, first clean up the APIs of coerce_to_domain() and some internal functions in parse_coerce.c so that we consistently pass around a CoercionContext along with CoercionForm. Previously, we sometimes passed an "isExplicit" boolean flag instead, which is strictly less information; and coerce_to_domain() didn't even get that, but instead had to reverse-engineer isExplicit from CoercionForm. That's contrary to the documentation in primnodes.h that says that CoercionForm only affects display and not semantics. I don't think this change fixes any live bugs, but it makes things more consistent. The main reason for doing it though is that now build_coercion_expression() receives ccontext, which it needs in order to be able to recursively invoke coerce_to_target_type(). Next, reimplement ArrayCoerceExpr so that the node does not directly know any details of what has to be done to the individual array elements while performing the array coercion. Instead, the per-element processing is represented by a sub-expression whose input is a source array element and whose output is a target array element. This simplifies life in parse_coerce.c, because it can build that sub-expression by a recursive invocation of coerce_to_target_type(). The executor now handles the per-element processing as a compiled expression instead of hard-wired code. The main advantage of this is that we can use a single ArrayCoerceExpr to handle as many as three successive steps per element: base type conversion, typmod coercion, and domain constraint checking. The old code used two stacked ArrayCoerceExprs to handle type + typmod coercion, which was pretty inefficient, and adding yet another array deconstruction to do domain constraint checking seemed very unappetizing. In the case where we just need a single, very simple coercion function, doing this straightforwardly leads to a noticeable increase in the per-array-element runtime cost. Hence, add an additional shortcut evalfunc in execExprInterp.c that skips unnecessary overhead for that specific form of expression. The runtime speed of simple cases is within 1% or so of where it was before, while cases that previously required two levels of array processing are significantly faster. Finally, create an implicit array type for every domain type, as we do for base types, enums, etc. Everything except the array-coercion case seems to just work without further effort. Tom Lane, reviewed by Andrew Dunstan Discussion: https://postgr.es/m/9852.1499791473@sss.pgh.pa.us
2017-09-08Allow a partitioned table to have a default partition.Robert Haas
Any tuples that don't route to any other partition will route to the default partition. Jeevan Ladhe, Beena Emerson, Ashutosh Bapat, Rahila Syed, and Robert Haas, with review and testing at various stages by (at least) Rushabh Lathia, Keith Fiske, Amit Langote, Amul Sul, Rajkumar Raghuanshi, Sven Kunze, Kyotaro Horiguchi, Thom Brown, Rafia Sabih, and Dilip Kumar. Discussion: http://postgr.es/m/CAH2L28tbN4SYyhS7YV1YBWcitkqbhSWfQCy0G=apRcC_PEO-bg@mail.gmail.com Discussion: http://postgr.es/m/CAOG9ApEYj34fWMcvBMBQ-YtqR9fTdXhdN82QEKG0SVZ6zeL1xg@mail.gmail.com
2017-08-30Force rescanning of parallel-aware scan nodes below a Gather[Merge].Tom Lane
The ExecReScan machinery contains various optimizations for postponing or skipping rescans of plan subtrees; for example a HashAgg node may conclude that it can re-use the table it built before, instead of re-reading its input subtree. But that is wrong if the input contains a parallel-aware table scan node, since the portion of the table scanned by the leader process is likely to vary from one rescan to the next. This explains the timing-dependent buildfarm failures we saw after commit a2b70c89c. The established mechanism for showing that a plan node's output is potentially variable is to mark it as depending on some runtime Param. Hence, to fix this, invent a dummy Param (one that has a PARAM_EXEC parameter number, but carries no actual value) associated with each Gather or GatherMerge node, mark parallel-aware nodes below that node as dependent on that Param, and arrange for ExecReScanGather[Merge] to flag that Param as changed whenever the Gather[Merge] node is rescanned. This solution breaks an undocumented assumption made by the parallel executor logic, namely that all rescans of nodes below a Gather[Merge] will happen synchronously during the ReScan of the top node itself. But that's fundamentally contrary to the design of the ExecReScan code, and so was doomed to fail someday anyway (even if you want to argue that the bug being fixed here wasn't a failure of that assumption). A follow-on patch will address that issue. In the meantime, the worst that's expected to happen is that given very bad timing luck, the leader might have to do all the work during a rescan, because workers think they have nothing to do, if they are able to start up before the eventual ReScan of the leader's parallel-aware table scan node has reset the shared scan state. Although this problem exists in 9.6, there does not seem to be any way for it to manifest there. Without GatherMerge, it seems that a plan tree that has a rescan-short-circuiting node below Gather will always also have one above it that will short-circuit in the same cases, preventing the Gather from being rescanned. Hence we won't take the risk of back-patching this change into 9.6. But v10 needs it. Discussion: https://postgr.es/m/CAA4eK1JkByysFJNh9M349u_nNjqETuEnY_y1VUc_kJiU0bxtaQ@mail.gmail.com
2017-08-15Fix up some misusage of appendStringInfo() and friendsPeter Eisentraut
Change to appendStringInfoChar() or appendStringInfoString() where those can be used. Author: David Rowley <david.rowley@2ndquadrant.com> Reviewed-by: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>
2017-07-21Use MINVALUE/MAXVALUE instead of UNBOUNDED for range partition bounds.Dean Rasheed
Previously, UNBOUNDED meant no lower bound when used in the FROM list, and no upper bound when used in the TO list, which was OK for single-column range partitioning, but problematic with multiple columns. For example, an upper bound of (10.0, UNBOUNDED) would not be collocated with a lower bound of (10.0, UNBOUNDED), thus making it difficult or impossible to define contiguous multi-column range partitions in some cases. Fix this by using MINVALUE and MAXVALUE instead of UNBOUNDED to represent a partition column that is unbounded below or above respectively. This syntax removes any ambiguity, and ensures that if one partition's lower bound equals another partition's upper bound, then the partitions are contiguous. Also drop the constraint prohibiting finite values after an unbounded column, and just document the fact that any values after MINVALUE or MAXVALUE are ignored. Previously it was necessary to repeat UNBOUNDED multiple times, which was needlessly verbose. Note: Forces a post-PG 10 beta2 initdb. Report by Amul Sul, original patch by Amit Langote with some additional hacking by me. Discussion: https://postgr.es/m/CAAJ_b947mowpLdxL3jo3YLKngRjrq9+Ej4ymduQTfYR+8=YAYQ@mail.gmail.com
2017-07-14Code review for NextValueExpr expression node type.Tom Lane
Add missing infrastructure for this node type, notably in ruleutils.c where its lack could demonstrably cause EXPLAIN to fail. Add outfuncs/readfuncs support. (outfuncs support is useful today for debugging purposes. The readfuncs support may never be needed, since at present it would only matter for parallel query and NextValueExpr should never appear in a parallelizable query; but it seems like a bad idea to have a primnode type that isn't fully supported here.) Teach planner infrastructure that NextValueExpr is a volatile, parallel-unsafe, non-leaky expression node with cost cpu_operator_cost. Given its limited scope of usage, there *might* be no live bug today from the lack of that knowledge, but it's certainly going to bite us on the rear someday. Teach pg_stat_statements about the new node type, too. While at it, also teach cost_qual_eval() that MinMaxExpr, SQLValueFunction, XmlExpr, and CoerceToDomain should be charged as cpu_operator_cost. Failing to do this for SQLValueFunction was an oversight in my commit 0bb51aa96. The others are longer-standing oversights, but no time like the present to fix them. (In principle, CoerceToDomain could have cost much higher than this, but it doesn't presently seem worth trying to examine the domain's constraints here.) Modify execExprInterp.c to execute NextValueExpr as an out-of-line function; it seems quite unlikely to me that it's worth insisting that it be inlined in all expression eval methods. Besides, providing the out-of-line function doesn't stop anyone from inlining if they want to. Adjust some places where NextValueExpr support had been inserted with the aid of a dartboard rather than keeping it in the same order as elsewhere. Discussion: https://postgr.es/m/23862.1499981661@sss.pgh.pa.us
2017-07-05Fix output of char node fieldsPeter Eisentraut
WRITE_CHAR_FIELD() didn't do any escaping, so that for example a zero byte would cause the whole output string to be truncated. To fix, pass the char through outToken(), so it is escaped like a string. Adjust the reading side to handle this.
2017-06-16Reconcile nodes/*funcs.c with PostgreSQL 10 work.Noah Misch
The _equalTableFunc() omission of coltypmods has semantic significance, but I did not track down resulting user-visible bugs, if any. The other changes are cosmetic only, affecting order. catversion bump due to readfuncs.c field order change.
2017-06-14Fix problems related to RangeTblEntry members enrname and enrtuples.Robert Haas
Commit 18ce3a4ab22d2984f8540ab480979c851dae5338 failed to update the comments in parsenodes.h for the new members, and made only incomplete updates to src/backend/nodes Thomas Munro, per a report from Noah Misch. Discussion: http://postgr.es/m/20170611062525.GA1628882@rfd.leadboat.com
2017-05-30Fix omission of locations in outfuncs/readfuncs partitioning node support.Tom Lane
We could have limped along without this for v10, which was my intention when I annotated the bug in commit 76a3df6e5. But consensus is that it's better to fix it now and take the cost of a post-beta1 initdb (which is needed because these node types are stored in pg_class.relpartbound). Since we're forcing initdb anyway, take the opportunity to make the node type identification strings match the node struct names, instead of being randomly different from them. Discussion: https://postgr.es/m/E1dFBEX-0004wt-8t@gemulon.postgresql.org