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2024-10-20SQL/JSON: Fix some oversights in commit b6e1157e7Amit Langote
The decision in b6e1157e7 to ignore raw_expr when evaluating a JsonValueExpr was incorrect. While its value is not ultimately used (since formatted_expr's value is), failing to initialize it can lead to problems, for instance, when the expression tree in raw_expr contains Aggref nodes, which must be initialized to ensure the parent Agg node works correctly. Also, optimize eval_const_expressions_mutator()'s handling of JsonValueExpr a bit. Currently, when formatted_expr cannot be folded into a constant, we end up processing it twice -- once directly in eval_const_expressions_mutator() and again recursively via ece_generic_processing(). This recursive processing is required to handle raw_expr. To avoid the redundant processing of formatted_expr, we now process raw_expr directly in eval_const_expressions_mutator(). Finally, update the comment of JsonValueExpr to describe the roles of raw_expr and formatted_expr more clearly. Bug: #18657 Reported-by: Alexander Lakhin <exclusion@gmail.com> Diagnosed-by: Fabio R. Sluzala <fabio3rs@gmail.com> Diagnosed-by: Tender Wang <tndrwang@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18657-1b90ccce2b16bdb8@postgresql.org Backpatch-through: 16
2024-09-27Recalculate where-needed data accurately after a join removal.Tom Lane
Up to now, remove_rel_from_query() has done a pretty shoddy job of updating our where-needed bitmaps (per-Var attr_needed and per-PlaceHolderVar ph_needed relid sets). It removed direct mentions of the to-be-removed baserel and outer join, which is the minimum amount of effort needed to keep the data structures self-consistent. But it didn't account for the fact that the removed join ON clause probably mentioned Vars of other relations, and those Vars might now not be needed as high up in the join tree as before. It's easy to show cases where this results in failing to remove a lower outer join that could also have been removed. To fix, recalculate the where-needed bitmaps from scratch after each successful join removal. This sounds expensive, but it seems to add only negligible planner runtime. (We cheat a little bit by preserving "relation 0" entries in the bitmaps, allowing us to skip re-scanning the targetlist and HAVING qual.) The submitted test case drew attention because we had successfully optimized away the lower join prior to v16. I suspect that that's somewhat accidental and there are related cases that were never optimized before and now can be. I've not tried to come up with one, though. Perhaps we should back-patch this into v16 and v17 to repair the performance regression. However, since it took a year for anyone to notice the problem, it can't be affecting too many people. Let's let the patch bake awhile in HEAD, and see if we get more complaints. Per bug #18627 from Mikaël Gourlaouen. No back-patch for now. Discussion: https://postgr.es/m/18627-44f950eb6a8416c2@postgresql.org
2024-09-17Add temporal PRIMARY KEY and UNIQUE constraintsPeter Eisentraut
Add WITHOUT OVERLAPS clause to PRIMARY KEY and UNIQUE constraints. These are backed by GiST indexes instead of B-tree indexes, since they are essentially exclusion constraints with = for the scalar parts of the key and && for the temporal part. (previously committed as 46a0cd4cefb, reverted by 46a0cd4cefb; the new part is this:) Because 'empty' && 'empty' is false, the temporal PK/UQ constraint allowed duplicates, which is confusing to users and breaks internal expectations. For instance, when GROUP BY checks functional dependencies on the PK, it allows selecting other columns from the table, but in the presence of duplicate keys you could get the value from any of their rows. So we need to forbid empties. This all means that at the moment we can only support ranges and multiranges for temporal PK/UQs, unlike the original patch (above). Documentation and tests for this are added. But this could conceivably be extended by introducing some more general support for the notion of "empty" for other types. Author: Paul A. Jungwirth <pj@illuminatedcomputing.com> Reviewed-by: Peter Eisentraut <peter@eisentraut.org> Reviewed-by: jian he <jian.universality@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/CA+renyUApHgSZF9-nd-a0+OPGharLQLO=mDHcY4_qQ0+noCUVg@mail.gmail.com
2024-09-10Add amgettreeheight index AM API routinePeter Eisentraut
The only current implementation is for btree where it calls _bt_getrootheight(). Other index types can now also use this to pass information to their amcostestimate routine. Previously, btree was hardcoded and other index types could not hook into the optimizer at this point. Author: Mark Dilger <mark.dilger@enterprisedb.com> Discussion: https://www.postgresql.org/message-id/flat/E72EAA49-354D-4C2E-8EB9-255197F55330@enterprisedb.com
2024-09-10Mark expressions nullable by grouping setsRichard Guo
When generating window_pathkeys, distinct_pathkeys, or sort_pathkeys, we failed to realize that the grouping/ordering expressions might be nullable by grouping sets. As a result, we may incorrectly deem that the PathKeys are redundant by EquivalenceClass processing and thus remove them from the pathkeys list. That would lead to wrong results in some cases. To fix this issue, we mark the grouping expressions nullable by grouping sets if that is the case. If the grouping expression is a Var or PlaceHolderVar or constructed from those, we can just add the RT index of the RTE_GROUP RTE to the existing nullingrels field(s); otherwise we have to add a PlaceHolderVar to carry on the nullingrel bit. However, we have to manually remove this nullingrel bit from expressions in various cases where these expressions are logically below the grouping step, such as when we generate groupClause pathkeys for grouping sets, or when we generate PathTarget for initial input to grouping nodes. Furthermore, in set_upper_references, the targetlist and quals of an Agg node should have nullingrels that include the effects of the grouping step, ie they will have nullingrels equal to the input Vars/PHVs' nullingrels plus the nullingrel bit that references the grouping RTE. In order to perform exact nullingrels matches, we also need to manually remove this nullingrel bit. Bump catversion because this changes the querytree produced by the parser. Thanks to Tom Lane for the idea to invent a new kind of RTE. Per reports from Geoff Winkless, Tobias Wendorff, Richard Guo from various threads. Author: Richard Guo Reviewed-by: Ashutosh Bapat, Sutou Kouhei Discussion: https://postgr.es/m/CAMbWs4_dp7e7oTwaiZeBX8+P1rXw4ThkZxh1QG81rhu9Z47VsQ@mail.gmail.com
2024-09-10Introduce an RTE for the grouping stepRichard Guo
If there are subqueries in the grouping expressions, each of these subqueries in the targetlist and HAVING clause is expanded into distinct SubPlan nodes. As a result, only one of these SubPlan nodes would be converted to reference to the grouping key column output by the Agg node; others would have to get evaluated afresh. This is not efficient, and with grouping sets this can cause wrong results issues in cases where they should go to NULL because they are from the wrong grouping set. Furthermore, during re-evaluation, these SubPlan nodes might use nulled column values from grouping sets, which is not correct. This issue is not limited to subqueries. For other types of expressions that are part of grouping items, if they are transformed into another form during preprocessing, they may fail to match lower target items. This can also lead to wrong results with grouping sets. To fix this issue, we introduce a new kind of RTE representing the output of the grouping step, with columns that are the Vars or expressions being grouped on. In the parser, we replace the grouping expressions in the targetlist and HAVING clause with Vars referencing this new RTE, so that the output of the parser directly expresses the semantic requirement that the grouping expressions be gotten from the grouping output rather than computed some other way. In the planner, we first preprocess all the columns of this new RTE and then replace any Vars in the targetlist and HAVING clause that reference this new RTE with the underlying grouping expressions, so that we will have only one instance of a SubPlan node for each subquery contained in the grouping expressions. Bump catversion because this changes the querytree produced by the parser. Thanks to Tom Lane for the idea to invent a new kind of RTE. Per reports from Geoff Winkless, Tobias Wendorff, Richard Guo from various threads. Author: Richard Guo Reviewed-by: Ashutosh Bapat, Sutou Kouhei Discussion: https://postgr.es/m/CAMbWs4_dp7e7oTwaiZeBX8+P1rXw4ThkZxh1QG81rhu9Z47VsQ@mail.gmail.com
2024-08-21Treat number of disabled nodes in a path as a separate cost metric.Robert Haas
Previously, when a path type was disabled by e.g. enable_seqscan=false, we either avoided generating that path type in the first place, or more commonly, we added a large constant, called disable_cost, to the estimated startup cost of that path. This latter approach can distort planning. For instance, an extremely expensive non-disabled path could seem to be worse than a disabled path, especially if the full cost of that path node need not be paid (e.g. due to a Limit). Or, as in the regression test whose expected output changes with this commit, the addition of disable_cost can make two paths that would normally be distinguishible in cost seem to have fuzzily the same cost. To fix that, we now count the number of disabled path nodes and consider that a high-order component of both the startup cost and the total cost. Hence, the path list is now sorted by disabled_nodes and then by total_cost, instead of just by the latter, and likewise for the partial path list. It is important that this number is a count and not simply a Boolean; else, as soon as we're unable to respect disabled path types in all portions of the path, we stop trying to avoid them where we can. Because the path list is now sorted by the number of disabled nodes, the join prechecks must compute the count of disabled nodes during the initial cost phase instead of postponing it to final cost time. Counts of disabled nodes do not cross subquery levels; at present, there is no reason for them to do so, since the we do not postpone path selection across subquery boundaries (see make_subplan). Reviewed by Andres Freund, Heikki Linnakangas, and David Rowley. Discussion: http://postgr.es/m/CA+TgmoZ_+MS+o6NeGK2xyBv-xM+w1AfFVuHE4f_aq6ekHv7YSQ@mail.gmail.com
2024-08-19Avoid failure to open dropped detached partitionAlvaro Herrera
When a partition is detached and immediately dropped, a prepared statement could try to compute a new partition descriptor that includes it. This leads to this kind of error: ERROR: could not open relation with OID 457639 Avoid this by skipping the partition in expand_partitioned_rtentry if it doesn't exist. Noted by me while investigating bug #18559. Kuntal Gosh helped to identify the exact failure. Backpatch to 14, where DETACH CONCURRENTLY was introduced. Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-by: Kuntal Ghosh <kuntalghosh.2007@gmail.com> Reviewed-by: Junwang Zhao <zhjwpku@gmail.com> Discussion: https://postgr.es/m/202408122233.bo4adt3vh5bi@alvherre.pgsql
2024-08-13Rename C23 keywordPeter Eisentraut
constexpr is a keyword in C23. Rename a conflicting identifier for future-proofing. Reviewed-by: Robert Haas <robertmhaas@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/08abc832-1384-4aca-a535-1a79765b565e%40eisentraut.org
2024-08-05Restrict accesses to non-system views and foreign tables during pg_dump.Masahiko Sawada
When pg_dump retrieves the list of database objects and performs the data dump, there was possibility that objects are replaced with others of the same name, such as views, and access them. This vulnerability could result in code execution with superuser privileges during the pg_dump process. This issue can arise when dumping data of sequences, foreign tables (only 13 or later), or tables registered with a WHERE clause in the extension configuration table. To address this, pg_dump now utilizes the newly introduced restrict_nonsystem_relation_kind GUC parameter to restrict the accesses to non-system views and foreign tables during the dump process. This new GUC parameter is added to back branches too, but these changes do not require cluster recreation. Back-patch to all supported branches. Reviewed-by: Noah Misch Security: CVE-2024-7348 Backpatch-through: 12
2024-07-30Fix partitionwise join with partially-redundant join clausesRichard Guo
To determine if the two relations being joined can use partitionwise join, we need to verify the existence of equi-join conditions involving pairs of matching partition keys for all partition keys. Currently we do that by looking through the join's restriction clauses. However, it has been discovered that this approach is insufficient, because there might be partition keys known equal by a specific EC, but they do not form a join clause because it happens that other members of the EC than the partition keys are constrained to become a join clause. To address this issue, in addition to examining the join's restriction clauses, we also check if any partition keys are known equal by ECs, by leveraging function exprs_known_equal(). To accomplish this, we enhance exprs_known_equal() to check equality per the semantics of the opfamily, if provided. It could be argued that exprs_known_equal() could be called O(N^2) times, where N is the number of partition key expressions, resulting in noticeable performance costs if there are a lot of partition key expressions. But I think this is not a problem. The number of a joinrel's partition key expressions would only be equal to the join degree, since each base relation within the join contributes only one partition key expression. That is to say, it does not scale with the number of partitions. A benchmark with a query involving 5-way joins of partitioned tables, each with 3 partition keys and 1000 partitions, shows that the planning time is not significantly affected by this patch (within the margin of error), particularly when compared to the impact caused by partitionwise join. Thanks to Tom Lane for the idea of leveraging exprs_known_equal() to check if partition keys are known equal by ECs. Author: Richard Guo, Tom Lane Reviewed-by: Tom Lane, Ashutosh Bapat, Robert Haas Discussion: https://postgr.es/m/CAN_9JTzo_2F5dKLqXVtDX5V6dwqB0Xk+ihstpKEt3a1LT6X78A@mail.gmail.com
2024-07-29Reduce memory used by partitionwise joinsRichard Guo
In try_partitionwise_join, we aim to break down the join between two partitioned relations into joins between matching partitions. To achieve this, we iterate through each pair of partitions from the two joining relations and create child-join relations for them. With potentially thousands of partitions, the local objects allocated in each iteration can accumulate significant memory usage. Therefore, we opt to eagerly free these local objects at the end of each iteration. In line with this approach, this patch frees the bitmap set that represents the relids of child-join relations at the end of each iteration. Additionally, it modifies build_child_join_rel() to reuse the AppendRelInfo structures generated within each iteration. Author: Ashutosh Bapat Reviewed-by: David Christensen, Richard Guo Discussion: https://postgr.es/m/CAExHW5s4EqY43oB=ne6B2=-xLgrs9ZGeTr1NXwkGFt2j-OmaQQ@mail.gmail.com
2024-07-29Simplify create_merge_append_path for clarityRichard Guo
We don't currently support parameterized MergeAppend paths: there's little use for an ordered path on the inside of a nestloop. Given this, we can simplify create_merge_append_path by directly setting param_info to NULL instead of calling get_appendrel_parampathinfo. We can also simplify the Assert for child paths a little bit. This change won't make any measurable difference in performance; it's just for clarity's sake. Author: Richard Guo Reviewed-by: Alena Rybakina, Paul A Jungwirth Discussion: https://postgr.es/m/CAMbWs4_n1bgH2nACMuGsXZct3KH6PBFS0tPdQsXdstRfyxTunQ@mail.gmail.com
2024-07-23Remove redundant code in create_gather_merge_pathRichard Guo
In create_gather_merge_path, we should always guarantee that the subpath is adequately ordered, and we do not add a Sort node in createplan.c for a Gather Merge node. Therefore, the 'else' branch in create_gather_merge_path, which computes the cost for a Sort node, is redundant. This patch removes the redundant code and emits an error if the subpath is not sufficiently ordered. Meanwhile, this patch changes the check for the subpath's pathkeys in create_gather_merge_plan to an Assert. Author: Richard Guo Discussion: https://postgr.es/m/CAMbWs48u=0bWf3epVtULjJ-=M9Hbkz+ieZQAOS=BfbXZFqbDCg@mail.gmail.com
2024-07-23Fix rowcount estimate for gather (merge) pathsRichard Guo
In the case of a parallel plan, when computing the number of tuples processed per worker, we divide the total number of tuples by the parallel_divisor obtained from get_parallel_divisor(), which accounts for the leader's contribution in addition to the number of workers. Accordingly, when estimating the number of tuples for gather (merge) nodes, we should multiply the number of tuples per worker by the same parallel_divisor to reverse the division. However, currently we use parallel_workers rather than parallel_divisor for the multiplication. This could result in an underestimation of the number of tuples for gather (merge) nodes, especially when there are fewer than four workers. This patch fixes this issue by using the same parallel_divisor for the multiplication. There is one ensuing plan change in the regression tests, but it looks reasonable and does not compromise its original purpose of testing parallel-aware hash join. In passing, this patch removes an unnecessary assignment for path.rows in create_gather_merge_path, and fixes an uninitialized-variable issue in generate_useful_gather_paths. No backpatch as this could result in plan changes. Author: Anthonin Bonnefoy Reviewed-by: Rafia Sabih, Richard Guo Discussion: https://postgr.es/m/CAO6_Xqr9+51NxgO=XospEkUeAg-p=EjAWmtpdcZwjRgGKJ53iA@mail.gmail.com
2024-07-04Assign error codes where missing for user-facing failuresMichael Paquier
All the errors triggered in the code paths patched here would cause the backend to issue an internal_error errcode, which is a state that should be used only for "can't happen" situations. However, these code paths are reachable by the regression tests, and could be seen by users in valid cases. Some regression tests expect internal errcodes as they manipulate the backend state to cause corruption (like checksums), or use elog() because it is more convenient (like injection points), these have no need to change. This reduces the number of internal failures triggered in a check-world by more than half, while providing correct errcodes for these valid cases. Reviewed-by: Robert Haas Discussion: https://postgr.es/m/Zic_GNgos5sMxKoa@paquier.xyz
2024-07-02Use TupleDescAttr macro consistentlyDavid Rowley
A few places were directly accessing the attrs[] array. This goes against the standards set by 2cd708452. Fix that. Discussion: https://postgr.es/m/CAApHDvrBztXP3yx=NKNmo3xwFAFhEdyPnvrDg3=M0RhDs+4vYw@mail.gmail.com
2024-06-19Fix possible Assert failure in cost_memoize_rescanDavid Rowley
In cost_memoize_rescan(), when calculating the hit_ratio using the calls and ndistinct estimations, if the value that was set in MemoizePath.calls had not been processed through clamp_row_est(), then it was possible that it was set to some non-integer value which could result in ndistinct being 1 higher than calls due to estimate_num_groups() performing clamp_row_est() on its input_rows. This could result in hit_ratio values slightly below 0.0, which would cause an Assert failure. The value of MemoizePath.calls comes from the final parameter in the create_memoize_path() function, of which we only have one true caller of. That caller passes outer_path->rows. All the core code I looked at always seems to call clamp_row_est() on the Path.rows, so there might have been no issues with any core Paths causing troubles here. The bug report was about a CustomPath with a non-clamped row estimated. The misbehavior as a result of this seems to be mostly limited to the Assert() failing. Aside from that, it seems the Memoize costs would just come out slightly higher than they should have, which is likely fairly harmless. Reported-by: Kohei KaiGai <kaigai@heterodb.com> Discussion: https://postgr.es/m/CAOP8fzZnTU+N64UYJYogb1hN-5hFP+PwTb3m_cnGAD7EsQwrKw@mail.gmail.com Reviewed-by: Richard Guo Backpatch-through: 14, where Memoize was introduced
2024-06-11Fix infer_arbiter_indexes() to not assume resultRelation is 1.Tom Lane
infer_arbiter_indexes failed to renumber varnos in index expressions or predicates that it got from the catalogs. This escaped detection up to now because the stored varnos in such trees will be 1, and an INSERT's result relation is usually the first rangetable entry, so that that was fine. However, in cases such as inserting through an updatable view, it's not fine, leading to failure to match the expressions to the query with ensuing "there is no unique or exclusion constraint matching the ON CONFLICT specification" errors. Fix by copy-and-paste from get_relation_info(). Per bug #18502 from Michael Wang. Back-patch to all supported versions. Discussion: https://postgr.es/m/18502-545b53f5b81e54e0@postgresql.org
2024-05-16Revert temporal primary keys and foreign keysPeter Eisentraut
This feature set did not handle empty ranges correctly, and it's now too late for PostgreSQL 17 to fix it. The following commits are reverted: 6db4598fcb8 Add stratnum GiST support function 46a0cd4cefb Add temporal PRIMARY KEY and UNIQUE constraints 86232a49a43 Fix comment on gist_stratnum_btree 030e10ff1a3 Rename pg_constraint.conwithoutoverlaps to conperiod a88c800deb6 Use daterange and YMD in without_overlaps tests instead of tsrange. 5577a71fb0c Use half-open interval notation in without_overlaps tests 34768ee3616 Add temporal FOREIGN KEY contraints 482e108cd38 Add test for REPLICA IDENTITY with a temporal key c3db1f30cba doc: clarify PERIOD and WITHOUT OVERLAPS in CREATE TABLE 144c2ce0cc7 Fix ON CONFLICT DO NOTHING/UPDATE for temporal indexes Discussion: https://www.postgresql.org/message-id/d0b64a7a-dfe4-4b84-a906-c7dedfa40a3e@eisentraut.org
2024-05-13Revert structural changes to not-null constraintsAlvaro Herrera
There are some problems with the new way to handle these constraints that were detected at the last minute, and require fixes that appear too invasive to be doing this late in the cycle. Revert this (again) for now, we'll try again with these problems fixed. The following commits are reverted: b0e96f311985 Catalog not-null constraints 9b581c534186 Disallow changing NO INHERIT status of a not-null constraint d0ec2ddbe088 Fix not-null constraint test ac22a9545ca9 Move privilege check to the right place b0f7dd915bca Check stack depth in new recursive functions 3af721794272 Update information_schema definition for not-null constraints c3709100be73 Fix propagating attnotnull in multiple inheritance d9f686a72ee9 Fix restore of not-null constraints with inheritance d72d32f52d26 Don't try to assign smart names to constraints 0cd711271d42 Better handle indirect constraint drops 13daa33fa5a6 Disallow NO INHERIT not-null constraints on partitioned tables d45597f72fe5 Disallow direct change of NO INHERIT of not-null constraints 21ac38f498b3 Fix inconsistencies in error messages Discussion: https://postgr.es/m/202405110940.joxlqcx4dogd@alvherre.pgsql
2024-05-10Fix ON CONFLICT DO NOTHING/UPDATE for temporal indexesPeter Eisentraut
A PRIMARY KEY or UNIQUE constraint with WITHOUT OVERLAPS will be a GiST index, not a B-Tree, but it will still have indisunique set. The code for ON CONFLICT fails if it sees a non-btree index that has indisunique. This commit fixes that and adds some tests. But now that we can't just test indisunique, we also need some extra checks to prevent DO UPDATE from running against a WITHOUT OVERLAPS constraint (because the conflict could happen against more than one row, and we'd only update one). Author: Paul A. Jungwirth <pj@illuminatedcomputing.com> Discussion: https://www.postgresql.org/message-id/1426589a-83cb-4a89-bf40-713970c07e63@illuminatedcomputing.com
2024-05-05Fix query pullup issue with WindowClause runConditionDavid Rowley
94985c210 added code to detect when WindowFuncs were monotonic and allowed additional quals to be "pushed down" into the subquery to be used as WindowClause runConditions in order to short-circuit execution in nodeWindowAgg.c. The Node representation of runConditions wasn't well selected and because we do qual pushdown before planning the subquery, the planning of the subquery could perform subquery pull-up of nested subqueries. For WindowFuncs with args, the arguments could be changed after pushing the qual down to the subquery. This was made more difficult by the fact that the code duplicated the WindowFunc inside an OpExpr to include in the WindowClauses runCondition field. This could result in duplication of subqueries and a pull-up of such a subquery could result in another initplan parameter being issued for the 2nd version of the subplan. This could result in errors such as: ERROR: WindowFunc not found in subplan target lists To fix this, we change the node representation of these run conditions and instead of storing an OpExpr containing the WindowFunc in a list inside WindowClause, we now store a new node type named WindowFuncRunCondition within a new field in the WindowFunc. These get transformed into OpExprs later in planning once subquery pull-up has been performed. This problem did exist in v15 and v16, but that was fixed by 9d36b883b and e5d20bbd. Cat version bump due to new node type and modifying WindowFunc struct. Bug: #18305 Reported-by: Zuming Jiang Discussion: https://postgr.es/m/18305-33c49b4c830b37b3%40postgresql.org
2024-04-16Ensure generated join clauses for child rels have correct relids.Tom Lane
When building a join clause derived from an EquivalenceClass, if the clause is to be used with an appendrel child relation then make sure its clause_relids include the relids of that child relation. Normally this would be true already because the EquivalenceMember would be a Var of that relation. However, if the appendrel represents a flattened UNION ALL construct then some child EquivalenceMembers could be constants with no relids. The resulting under-marked clause is problematic because it could mislead join_clause_is_movable_into about where the clause should be evaluated. We do not have an example showing incorrect plan generation, but there are existing cases in the regression tests that will fail the Asserts this patch adds to get_baserel_parampathinfo. A similarly wrong conclusion about a clause being considered by get_joinrel_parampathinfo would lead to wrong placement of the clause. (This also squares with the way that clause_relids is calculated for non-equijoin clauses in adjust_appendrel_attrs.) The other reason for wanting these new Asserts is that the previous blithe assumption that the results of generate_join_implied_equalities "necessarily satisfy join_clause_is_movable_into" turns out to be wrong pre-v16. If it's still wrong it'd be good to find out. Per bug #18429 from Benoît Ryder. The bug as filed was fixed by commit 2489d76c4, but these changes correlate with the fix we will need to apply in pre-v16 branches. Discussion: https://postgr.es/m/18429-8982d4a348cc86c6@postgresql.org
2024-04-15Fix type-checking of RECORD-returning functions in FROM, redux.Tom Lane
Commit 2ed8f9a01 intended to institute a policy that if a RangeTblFunction has a coldeflist, then the function return type is certainly RECORD, and we should use the coldeflist as the source of truth about what the columns of the record type are. When the original function has been folded to a constant, inspection of the constant might give a different answer. This situation will lead to a tuple-type-mismatch error at execution, but up until that point we need to consistently believe the coldeflist, or we'll have problems from different bits of code reaching different conclusions. expandRTE didn't get that memo though, and would try to produce a tupdesc based on the constant in this situation, leading to an assertion failure. (Desultory testing suggests that non-assert builds often manage to give the expected error, although I also saw a "cache lookup failed for type 0" error, and it seems at least possible that a crash could happen.) Some other callers of get_expr_result_type and get_expr_result_tupdesc were also being incautious about this. While none of them seem to have actual bugs, they're working harder than necessary in this case, besides which it seems safest to have an explicit policy of not using those functions on an RTE with a coldeflist. Adjust the code accordingly, and add commentary to funcapi.c about this policy. Also fix an obsolete comment that claimed "get_expr_result_type() doesn't know how to extract type info from a RECORD constant". That hasn't been true since commit d57534740. Per bug #18422 from Alexander Lakhin. As with the previous commit, back-patch to all supported branches. Discussion: https://postgr.es/m/18422-89ca86c8eac5246d@postgresql.org
2024-04-12Fix IS [NOT] NULL qual optimization for inheritance tablesDavid Rowley
b262ad440 added code to have the planner remove redundant IS NOT NULL quals and eliminate needless scans for IS NULL quals on tables where the qual's column has a NOT NULL constraint. That commit failed to consider that an inheritance parent table could have differing NOT NULL constraints between the parent and the child. This caused issues as if we eliminated a qual on the parent, when applying the quals to child tables in apply_child_basequals(), the qual might not have been added to the parent's baserestrictinfo. Here we fix this by not applying the optimization to remove redundant quals to RelOptInfos belonging to inheritance parents and applying the optimization again in apply_child_basequals(). Effectively, this means that the parent and child are considered independently as the parent has both an inh=true and inh=false RTE and we still apply the optimization to the RelOptInfo corresponding to the inh=false RTE. We're able to still apply the optimization in add_base_clause_to_rel() for partitioned tables as the NULLability of partitions must match that of their parent. And, if we ever expand restriction_is_always_false() and restriction_is_always_true() to handle partition constraints then we can apply the same logic as, even in multi-level partitioned tables, there's no way to route values to a partition when the qual does not match the partition qual of the partitioned table's parent partition. The same is true for CHECK constraints as those must also match between arent partitioned tables and their partitions. Author: Richard Guo, David Rowley Discussion: https://postgr.es/m/CAMbWs4930gQSZmjR7aANzEapdy61gCg6z8dT-kAEYD0sYWKPdQ@mail.gmail.com
2024-03-30Add support for MERGE ... WHEN NOT MATCHED BY SOURCE.Dean Rasheed
This allows MERGE commands to include WHEN NOT MATCHED BY SOURCE actions, which operate on rows that exist in the target relation, but not in the data source. These actions can execute UPDATE, DELETE, or DO NOTHING sub-commands. This is in contrast to already-supported WHEN NOT MATCHED actions, which operate on rows that exist in the data source, but not in the target relation. To make this distinction clearer, such actions may now be written as WHEN NOT MATCHED BY TARGET. Writing WHEN NOT MATCHED without specifying BY SOURCE or BY TARGET is equivalent to writing WHEN NOT MATCHED BY TARGET. Dean Rasheed, reviewed by Alvaro Herrera, Ted Yu and Vik Fearing. Discussion: https://postgr.es/m/CAEZATCWqnKGc57Y_JanUBHQXNKcXd7r=0R4NEZUVwP+syRkWbA@mail.gmail.com
2024-03-26Propagate pathkeys from CTEs up to the outer query.Tom Lane
If we know the sort order of a CTE's output, and it is relevant to the outer query, label the CTE's outer-query access path using those pathkeys. This may enable optimizations such as avoiding a sort in the outer query. The code for hoisting pathkeys into the outer query already exists for regular RTE_SUBQUERY subqueries, but it wasn't getting used for CTEs, possibly out of concern for maintaining an optimization fence between the CTE and the outer query. However, on the same arguments used for commit f7816aec2, there seems no harm in letting the outer query know what the inner query decided to do. In support of this, we now remember the best Path as well as Plan for each subquery for the rest of the planner run. There may be future applications for having that at hand, and it surely costs little to build one more List. Richard Guo (minor mods by me) Discussion: https://postgr.es/m/CAMbWs49xYd3f8CrE8-WW3--dV1zH_sDSDn-vs2DzHj81Wcnsew@mail.gmail.com
2024-03-25Refactor predicate_{implied,refuted}_by_simple_clause.Tom Lane
Put the node-type-dependent operations into switches on nodeTag. This should ease addition of new proof rules for other expression node types. There is no functional change, although some tests are made in a different order than before. Also, add a couple of new cross-checks in test_predtest.c. James Coleman (part of a larger patch series) Discussion: https://postgr.es/m/CAAaqYe8Bo4bf_i6qKj8KBsmHMYXhe3Xt6vOe3OBQnOaf3_XBWg@mail.gmail.com
2024-03-25Code review for 6190d828cd2Amit Langote
* Fix the comment of init_dummy_sjinfo() to remove references to non-existing parameters 'rel1' and 'rel2'. * Adjust consider_new_or_clause() to call init_dummy_sjinfo() to make up a SpecialJoinInfo for inner joins like other code sites that were adjusted in 6190d828cd2 to do so. Author: Richard Guo <guofenglinux@gmail.com> Reported-by: Richard Guo <guofenglinux@gmail.com> Discussion: https://postgr.es/m/CAExHW5tHqEf3ASVqvFFcghYGPfpy7o3xnvhHwBGbJFMRH8KjNw@mail.gmail.com
2024-03-25Reduce memory used by partitionwise joinsAmit Langote
Specifically, this commit reduces the memory consumed by the SpecialJoinInfos that are allocated for child joins in try_partitionwise_join() by freeing them at the end of creating paths for each child join. A SpecialJoinInfo allocated for a given child join is a copy of the parent join's SpecialJoinInfo, which contains the translated copies of the various Relids bitmapsets and semi_rhs_exprs, which is a List of Nodes. The newly added freeing step frees the struct itself and the various bitmapsets, but not semi_rhs_exprs, because there's no handy function to free the memory of Node trees. Author: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com> Reviewed-by: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Amit Langote <amitlangote09@gmail.com> Reviewed-by: Andrey Lepikhov <a.lepikhov@postgrespro.ru> Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com> Discussion: https://postgr.es/m/CAExHW5tHqEf3ASVqvFFcghYGPfpy7o3xnvhHwBGbJFMRH8KjNw@mail.gmail.com
2024-03-21Add SQL/JSON query functionsAmit Langote
This introduces the following SQL/JSON functions for querying JSON data using jsonpath expressions: JSON_EXISTS(), which can be used to apply a jsonpath expression to a JSON value to check if it yields any values. JSON_QUERY(), which can be used to to apply a jsonpath expression to a JSON value to get a JSON object, an array, or a string. There are various options to control whether multi-value result uses array wrappers and whether the singleton scalar strings are quoted or not. JSON_VALUE(), which can be used to apply a jsonpath expression to a JSON value to return a single scalar value, producing an error if it multiple values are matched. Both JSON_VALUE() and JSON_QUERY() functions have options for handling EMPTY and ERROR conditions, which can be used to specify the behavior when no values are matched and when an error occurs during jsonpath evaluation, respectively. Author: Nikita Glukhov <n.gluhov@postgrespro.ru> Author: Teodor Sigaev <teodor@sigaev.ru> Author: Oleg Bartunov <obartunov@gmail.com> Author: Alexander Korotkov <aekorotkov@gmail.com> Author: Andrew Dunstan <andrew@dunslane.net> Author: Amit Langote <amitlangote09@gmail.com> Author: Peter Eisentraut <peter@eisentraut.org> Author: Jian He <jian.universality@gmail.com> Reviewers have included (in no particular order): Andres Freund, Alexander Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zihong Yu, Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby, Álvaro Herrera, Jian He, Anton A. Melnikov, Nikita Malakhov, Peter Eisentraut, Tomas Vondra Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru Discussion: https://postgr.es/m/20220616233130.rparivafipt6doj3@alap3.anarazel.de Discussion: https://postgr.es/m/abd9b83b-aa66-f230-3d6d-734817f0995d%40postgresql.org Discussion: https://postgr.es/m/CA+HiwqHROpf9e644D8BRqYvaAPmgBZVup-xKMDPk-nd4EpgzHw@mail.gmail.com Discussion: https://postgr.es/m/CA+HiwqE4XTdfb1nW=Ojoy_tQSRhYt-q_kb6i5d4xcKyrLC1Nbg@mail.gmail.com
2024-03-19Postpone reparameterization of paths until create_plan().Tom Lane
When considering nestloop paths for individual partitions within a partitionwise join, if the inner path is parameterized, it is parameterized by the topmost parent of the outer rel, not the corresponding outer rel itself. Therefore, we need to translate the parameterization so that the inner path is parameterized by the corresponding outer rel. Up to now, we did this while generating join paths. However, that's problematic because we must also translate some expressions that are shared across all paths for a relation, such as restriction clauses (kept in the RelOptInfo and/or IndexOptInfo) and TableSampleClauses (kept in the RangeTblEntry). The existing code fails to translate these at all, leading to wrong answers, odd failures such as "variable not found in subplan target list", or executor crashes. But we can't modify them during path generation, because that would break things if we end up choosing some non-partitioned-join path. So this patch postpones reparameterization of the inner path until createplan.c, where it is safe to modify the referenced RangeTblEntry, RelOptInfo or IndexOptInfo, because we have made a final choice of which Path to use. We do still have to check during path generation that the reparameterization will be possible. So we introduce a new function path_is_reparameterizable_by_child() to detect that. The duplication between path_is_reparameterizable_by_child() and reparameterize_path_by_child() is a bit annoying, but there seems no other good answer. A small benefit is that we can avoid building useless reparameterized trees in cases where a non-partitioned join is ultimately chosen. Also, reparameterize_path_by_child() can now be allowed to scribble on the input paths, saving a few cycles. This fix repairs the same problems previously addressed in the back branches by commits 62f120203 et al. Richard Guo, reviewed at various times by Ashutosh Bapat, Andrei Lepikhov, Alena Rybakina, Robert Haas, and myself Discussion: https://postgr.es/m/CAMbWs496+N=UAjOc=rcD3P7B6oJe4rZw08e_TZRUsWbPxZW3Tw@mail.gmail.com
2024-03-17Add RETURNING support to MERGE.Dean Rasheed
This allows a RETURNING clause to be appended to a MERGE query, to return values based on each row inserted, updated, or deleted. As with plain INSERT, UPDATE, and DELETE commands, the returned values are based on the new contents of the target table for INSERT and UPDATE actions, and on its old contents for DELETE actions. Values from the source relation may also be returned. As with INSERT/UPDATE/DELETE, the output of MERGE ... RETURNING may be used as the source relation for other operations such as WITH queries and COPY commands. Additionally, a special function merge_action() is provided, which returns 'INSERT', 'UPDATE', or 'DELETE', depending on the action executed for each row. The merge_action() function can be used anywhere in the RETURNING list, including in arbitrary expressions and subqueries, but it is an error to use it anywhere outside of a MERGE query's RETURNING list. Dean Rasheed, reviewed by Isaac Morland, Vik Fearing, Alvaro Herrera, Gurjeet Singh, Jian He, Jeff Davis, Merlin Moncure, Peter Eisentraut, and Wolfgang Walther. Discussion: http://postgr.es/m/CAEZATCWePEGQR5LBn-vD6SfeLZafzEm2Qy_L_Oky2=qw2w3Pzg@mail.gmail.com
2024-03-13Make the order of the header file includes consistentPeter Eisentraut
Similar to commit 7e735035f20. Author: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/CAMbWs4-WhpCFMbXCjtJ%2BFzmjfPrp7Hw1pk4p%2BZpU95Kh3ofZ1A%40mail.gmail.com
2024-03-12Fix confusion about the return rowtype of SQL-language procedures.Tom Lane
There is a very ancient hack in check_sql_fn_retval that allows a single SELECT targetlist entry of composite type to be taken as supplying all the output columns of a function returning composite. (This is grotty and fundamentally ambiguous, but it's really hard to do nested composite-returning functions without it.) As far as I know, that doesn't cause any problems in ordinary functions. It's disastrous for procedures however. All procedures that have any output parameters are labeled with prorettype RECORD, and the CALL code expects it will get back a record with one column per output parameter, regardless of whether any of those parameters is composite. Doing something else leads to an assertion failure or core dump. This is simple enough to fix: we just need to not apply that rule when considering procedures. However, that requires adding another argument to check_sql_fn_retval, which at least in principle might be getting called by external callers. Therefore, in the back branches convert check_sql_fn_retval into an ABI-preserving wrapper around a new function check_sql_fn_retval_ext. Per report from Yahor Yuzefovich. This has been broken since we implemented procedures, so back-patch to all supported branches. Discussion: https://postgr.es/m/CABz5gWHSjj2df6uG0NRiDhZ_Uz=Y8t0FJP-_SVSsRsnrQT76Gg@mail.gmail.com
2024-03-06Fix type-checking of RECORD-returning functions in FROM.Tom Lane
In the corner case where a function returning RECORD has been simplified to a RECORD constant or an inlined ROW() expression, ExecInitFunctionScan failed to cross-check the function's result rowtype against the coldeflist provided by the calling query. That happened because get_expr_result_type is able to extract a tupdesc from such expressions, which led ExecInitFunctionScan to ignore the coldeflist. (Instead, it used the extracted tupdesc to check the function's output, which of course always succeeds.) I have not been able to demonstrate any really serious consequences from this, because if some column of the result is of the wrong type and is directly referenced by a Var of the calling query, CheckVarSlotCompatibility will catch it. However, we definitely do fail to report the case where the function returns more columns than the coldeflist expects, and in the converse case where it returns fewer columns, we get an assert failure (but, seemingly, no worse results in non-assert builds). To fix, always build the expected tupdesc from the coldeflist if there is one, and consult get_expr_result_type only when there isn't one. Also remove the failing Assert, even though it is no longer reached after this fix. It doesn't seem to be adding anything useful, since later checking will deal with cases with the wrong number of columns. The only other place I could find that is doing something similar is inline_set_returning_function. There's no live bug there because we cannot be looking at a Const or RowExpr, but for consistency change that code to agree with ExecInitFunctionScan. Per report from PetSerAl. After some debate I've concluded that this should be back-patched. There is a small risk that somebody has been relying on such a case not throwing an error, but I judge this outweighed by the risk that I've missed some way in which the failure to cross-check has worse consequences than sketched above. Discussion: https://postgr.es/m/CAKygsHSerA1eXsJHR9wft3Gn3wfHQ5RfP8XHBzF70_qcrrRvEg@mail.gmail.com
2024-03-04Remove unused #include's from backend .c filesPeter Eisentraut
as determined by include-what-you-use (IWYU) While IWYU also suggests to *add* a bunch of #include's (which is its main purpose), this patch does not do that. In some cases, a more specific #include replaces another less specific one. Some manual adjustments of the automatic result: - IWYU currently doesn't know about includes that provide global variable declarations (like -Wmissing-variable-declarations), so those includes are being kept manually. - All includes for port(ability) headers are being kept for now, to play it safe. - No changes of catalog/pg_foo.h to catalog/pg_foo_d.h, to keep the patch from exploding in size. Note that this patch touches just *.c files, so nothing declared in header files changes in hidden ways. As a small example, in src/backend/access/transam/rmgr.c, some IWYU pragma annotations are added to handle a special case there. Discussion: https://www.postgresql.org/message-id/flat/af837490-6b2f-46df-ba05-37ea6a6653fc%40eisentraut.org
2024-02-29Support MERGE into updatable views.Dean Rasheed
This allows the target relation of MERGE to be an auto-updatable or trigger-updatable view, and includes support for WITH CHECK OPTION, security barrier views, and security invoker views. A trigger-updatable view must have INSTEAD OF triggers for every type of action (INSERT, UPDATE, and DELETE) mentioned in the MERGE command. An auto-updatable view must not have any INSTEAD OF triggers. Mixing auto-update and trigger-update actions (i.e., having a partial set of INSTEAD OF triggers) is not supported. Rule-updatable views are also not supported, since there is no rewriter support for non-SELECT rules with MERGE operations. Dean Rasheed, reviewed by Jian He and Alvaro Herrera. Discussion: https://postgr.es/m/CAEZATCVcB1g0nmxuEc-A+gGB0HnfcGQNGYH7gS=7rq0u0zOBXA@mail.gmail.com
2024-02-23Avoid dangling-pointer problem with partitionwise joins under GEQO.Tom Lane
build_child_join_sjinfo creates a derived SpecialJoinInfo in the short-lived GEQO context, but afterwards the semi_rhs_exprs from that may be used in a UniquePath for a child base relation. This breaks the expectation that all base-relation-level structures are in the planning-lifespan context, leading to use of a dangling pointer with probable ensuing crash later on in create_unique_plan. To fix, copy the expression trees when making a UniquePath. Per bug #18360 from Alexander Lakhin. This has been broken since partitionwise joins were added, so back-patch to all supported branches. Discussion: https://postgr.es/m/18360-a23caf3157f34e62@postgresql.org
2024-02-16Add missing check_stack_depth() to some recursive functionsAlexander Korotkov
Reported-by: Egor Chindyaskin, Alexander Lakhin Discussion: https://postgr.es/m/1672760457.940462079%40f306.i.mail.ru
2024-02-15Clarify the 'rows' parameter in create_append_pathDavid Rowley
This is extracted from a larger patch to improve the UNION planner. While working on that, I found myself having to check what the 'rows' parameter is for. It's not obvious that passing a negative number is the way to have the rows estimate calculated and to find that out you need to read code in create_append_path() and in cost_append(). Discussion: https://postgr.es/m/CAApHDvpb_63XQodmxKUF8vb9M7CxyUyT4sWvEgqeQU-GB7QFoQ@mail.gmail.com
2024-02-01Fix costing bug in MergeAppendDavid Rowley
When building a MergeAppendPath which has child paths that are not sorted correctly for the MergeAppend's sort order, we apply the cost of sorting those paths to the MergeAppendPath costs. Here we fix a bug where the number of tuples specified that needed to be sorted was effectively pg_class.reltuples rather than the number of expected row in the subpath. This effectively penalizes MergeAppend plans any time any filter is present on the MergeAppend subpath as the sort cost added is to sort all tuples in the table rather than just the ones expected the path to return. This did not affect UNION ALL type queries as the RelOptInfo tuples is set from the subquery's path rows. It does affect MergeAppends uses for inheritance and partitioned tables. This is a long-standing bug introduced when MergeAppend was first added in 11cad29c9. No backpatch as this could result in plan changes. Author: Alexander Kuzmenkov Reviewed-by: Ashutosh Bapat, Aleksander Alekseev, David Rowley Discussion: https://postgr.es/m/CALzhyqyhoXQDR-Usd_0HeWk%3DuqNLzoVeT8KhRoo%3DpV_KzgO3QQ%40mail.gmail.com
2024-01-26Compare varnullingrels too in assign_param_for_var().Tom Lane
Oversight in 2489d76c4. Preliminary analysis suggests that the problem may be unreachable --- but if we did have instances of the same column with different varnullingrels, we'd surely need to treat them as different Params. Discussion: https://postgr.es/m/412552.1706203379@sss.pgh.pa.us
2024-01-23Add better handling of redundant IS [NOT] NULL qualsDavid Rowley
Until now PostgreSQL has not been very smart about optimizing away IS NOT NULL base quals on columns defined as NOT NULL. The evaluation of these needless quals adds overhead. Ordinarily, anyone who came complaining about that would likely just have been told to not include the qual in their query if it's not required. However, a recent bug report indicates this might not always be possible. Bug 17540 highlighted that when we optimize Min/Max aggregates the IS NOT NULL qual that the planner adds to make the rewritten plan ignore NULLs can cause issues with poor index choice. That particular case demonstrated that other quals, especially ones where no statistics are available to allow the planner a chance at estimating an approximate selectivity for can result in poor index choice due to cheap startup paths being prefered with LIMIT 1. Here we take generic approach to fixing this by having the planner check for NOT NULL columns and just have the planner remove these quals (when they're not needed) for all queries, not just when optimizing Min/Max aggregates. Additionally, here we also detect IS NULL quals on a NOT NULL column and transform that into a gating qual so that we don't have to perform the scan at all. This also works for join relations when the Var is not nullable by any outer join. This also helps with the self-join removal work as it must replace strict join quals with IS NOT NULL quals to ensure equivalence with the original query. Author: David Rowley, Richard Guo, Andy Fan Reviewed-by: Richard Guo, David Rowley Discussion: https://postgr.es/m/CAApHDvqg6XZDhYRPz0zgOcevSMo0d3vxA9DvHrZtKfqO30WTnw@mail.gmail.com Discussion: https://postgr.es/m/17540-7aa1855ad5ec18b4%40postgresql.org
2024-01-10Fix Asserts in calc_non_nestloop_required_outer().Tom Lane
These were not testing the same thing as the comparable Assert in calc_nestloop_required_outer(), because we neglected to map the given Paths' relids to top-level relids. When considering a partition child join the latter is the correct thing to do. This oversight is old, but since it's only an overly-weak Assert check there doesn't seem to be much value in back-patching. Richard Guo (with cosmetic changes and comment updates by me) Discussion: https://postgr.es/m/CAMbWs49sqbe9GBZ8sy8dSfKRNURgicR85HX8vgzcgQsPF0XY1w@mail.gmail.com
2024-01-08Allow examine_simple_variable() to work on INSERT RETURNING Vars.Tom Lane
Since commit 599b33b94, this function assumed that every RTE_RELATION RangeTblEntry would have an associated RelOptInfo. But that's not so: we only build RelOptInfos for relations that are scanned by the query. In particular the target of an INSERT won't have one, so that Vars appearing in an INSERT ... RETURNING list will not have an associated RelOptInfo. This apparently wasn't a problem before commit f7816aec2 taught examine_simple_variable() to drill down into CTEs containing INSERT RETURNING, but it is now. To fix, add a fallback code path that gets the userid to use directly from the RTEPermissionInfo associated with the RTE. (Sadly, we must have two code paths, because not every RTE has a RTEPermissionInfo either.) Per report from Alexander Lakhin. No back-patch, since the case is apparently unreachable before f7816aec2. Discussion: https://postgr.es/m/608a4886-6c60-0f9e-97d5-591256bd4150@gmail.com
2024-01-03Update copyright for 2024Bruce Momjian
Reported-by: Michael Paquier Discussion: https://postgr.es/m/ZZKTDPxBBMt3C0J9@paquier.xyz Backpatch-through: 12
2023-12-19Prevent integer overflow when forming tuple width estimates.Tom Lane
It's at least theoretically possible to overflow int32 when adding up column width estimates to make a row width estimate. (The bug example isn't terribly convincing as a real use-case, but perhaps wide joins would provide a more plausible route to trouble.) This'd lead to assertion failures or silly planner behavior. To forestall it, make the relevant functions compute their running sums in int64 arithmetic and then clamp to int32 range at the end. We can reasonably assume that MaxAllocSize is a hard limit on actual tuple width, so clamping to that is simply a correction for dubious input values, and there's no need to go as far as widening width variables to int64 everywhere. Per bug #18247 from RekGRpth. There've been no reports of this issue arising in practical cases, so I feel no need to back-patch. Richard Guo and Tom Lane Discussion: https://postgr.es/m/18247-11ac477f02954422@postgresql.org
2023-11-16Ensure we preprocess expressions before checking their volatility.Tom Lane
contain_mutable_functions and contain_volatile_functions give reliable answers only after expression preprocessing (specifically eval_const_expressions). Some places understand this, but some did not get the memo --- which is not entirely their fault, because the problem is documented only in places far away from those functions. Introduce wrapper functions that allow doing the right thing easily, and add commentary in hopes of preventing future mistakes from copy-and-paste of code that's only conditionally safe. Two actual bugs of this ilk are fixed here. We failed to preprocess column GENERATED expressions before checking mutability, so that the code could fail to detect the use of a volatile function default-argument expression, or it could reject a polymorphic function that is actually immutable on the datatype of interest. Likewise, column DEFAULT expressions weren't preprocessed before determining if it's safe to apply the attmissingval mechanism. A false negative would just result in an unnecessary table rewrite, but a false positive could allow the attmissingval mechanism to be used in a case where it should not be, resulting in unexpected initial values in a new column. In passing, re-order the steps in ComputePartitionAttrs so that its checks for invalid column references are done before applying expression_planner, rather than after. The previous coding would not complain if a partition expression contains a disallowed column reference that gets optimized away by constant folding, which seems to me to be a behavior we do not want. Per bug #18097 from Jim Keener. Back-patch to all supported versions. Discussion: https://postgr.es/m/18097-ebb179674f22932f@postgresql.org