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* Update copyright for 2021Bruce Momjian2021-01-02
| | | | Backpatch-through: 9.5
* Support subscripting of arbitrary types, not only arrays.Tom Lane2020-12-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch generalizes the subscripting infrastructure so that any data type can be subscripted, if it provides a handler function to define what that means. Traditional variable-length (varlena) arrays all use array_subscript_handler(), while the existing fixed-length types that support subscripting use raw_array_subscript_handler(). It's expected that other types that want to use subscripting notation will define their own handlers. (This patch provides no such new features, though; it only lays the foundation for them.) To do this, move the parser's semantic processing of subscripts (including coercion to whatever data type is required) into a method callback supplied by the handler. On the execution side, replace the ExecEvalSubscriptingRef* layer of functions with direct calls to callback-supplied execution routines. (Thus, essentially no new run-time overhead should be caused by this patch. Indeed, there is room to remove some overhead by supplying specialized execution routines. This patch does a little bit in that line, but more could be done.) Additional work is required here and there to remove formerly hard-wired assumptions about the result type, collation, etc of a SubscriptingRef expression node; and to remove assumptions that the subscript values must be integers. One useful side-effect of this is that we now have a less squishy mechanism for identifying whether a data type is a "true" array: instead of wiring in weird rules about typlen, we can look to see if pg_type.typsubscript == F_ARRAY_SUBSCRIPT_HANDLER. For this to be bulletproof, we have to forbid user-defined types from using that handler directly; but there seems no good reason for them to do so. This patch also removes assumptions that the number of subscripts is limited to MAXDIM (6), or indeed has any hard-wired limit. That limit still applies to types handled by array_subscript_handler or raw_array_subscript_handler, but to discourage other dependencies on this constant, I've moved it from c.h to utils/array.h. Dmitry Dolgov, reviewed at various times by Tom Lane, Arthur Zakirov, Peter Eisentraut, Pavel Stehule Discussion: https://postgr.es/m/CA+q6zcVDuGBv=M0FqBYX8DPebS3F_0KQ6OVFobGJPM507_SZ_w@mail.gmail.com Discussion: https://postgr.es/m/CA+q6zcVovR+XY4mfk-7oNk-rF91gH0PebnNfuUjuuDsyHjOcVA@mail.gmail.com
* Add for_each_from, to simplify loops starting from non-first list cells.Tom Lane2020-09-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have a dozen or so places that need to iterate over all but the first cell of a List. Prior to v13 this was typically written as for_each_cell(lc, lnext(list_head(list))) Commit 1cff1b95a changed these to for_each_cell(lc, list, list_second_cell(list)) This patch introduces a new macro for_each_from() which expresses the start point as a list index, allowing these to be written as for_each_from(lc, list, 1) This is marginally more efficient, since ForEachState.i can be initialized directly instead of backing into it from a ListCell address. It also seems clearer and less typo-prone. Some of the remaining uses of for_each_cell() look like they could profitably be changed to for_each_from(), but here I confined myself to changing uses of list_second_cell(). Also, fix for_each_cell_setup() and for_both_cell_setup() to const-ify their arguments; that's a simple oversight in 1cff1b95a. Back-patch into v13, on the grounds that (1) the const-ification is a minor bug fix, and (2) it's better for back-patching purposes if we only have two ways to write these loops rather than three. In HEAD, also remove list_third_cell() and list_fourth_cell(), which were also introduced in 1cff1b95a, and are unused as of cc99baa43. It seems unlikely that any third-party code would have started to use them already; anyone who has can be directed to list_nth_cell instead. Discussion: https://postgr.es/m/CAApHDvpo1zj9KhEpU2cCRZfSM3Q6XGdhzuAS2v79PH7WJBkYVA@mail.gmail.com
* Suppress unnecessary RelabelType nodes in yet more cases.Tom Lane2020-08-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit a477bfc1d fixed eval_const_expressions() to ensure that it didn't generate unnecessary RelabelType nodes, but I failed to notice that some other places in the planner had the same issue. Really noplace in the planner should be using plain makeRelabelType(), for fear of generating expressions that should be equal() to semantically equivalent trees, but aren't. An example is that because canonicalize_ec_expression() failed to be careful about this, we could end up with an equivalence class containing both a plain Const, and a Const-with-RelabelType representing exactly the same value. So far as I can tell this led to no visible misbehavior, but we did waste a bunch of cycles generating and evaluating "Const = Const-with-RelabelType" to prove such entries are redundant. Hence, move the support function added by a477bfc1d to where it can be more generally useful, and use it in the places where planner code previously used makeRelabelType. Back-patch to v12, like the previous patch. While I have no concrete evidence of any real misbehavior here, it's certainly possible that I overlooked a case where equivalent expressions that aren't equal() could cause a user-visible problem. In any case carrying extra RelabelType nodes through planning to execution isn't very desirable. Discussion: https://postgr.es/m/1311836.1597781384@sss.pgh.pa.us
* Update copyrights for 2020Bruce Momjian2020-01-01
| | | | Backpatch-through: update all files in master, backpatch legal files through 9.4
* Prevent overly-aggressive collapsing of joins to RTE_RESULT relations.Tom Lane2019-12-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The RTE_RESULT simplification logic added by commit 4be058fe9 had a flaw: it would collapse out a RTE_RESULT that is due to compute a PlaceHolderVar, and reassign the PHV to the parent join level, even if another input relation of the join contained a lateral reference to the PHV. That can't work because the PHV would be computed too late. In practice it led to failures of internal sanity checks later in planning (either assertion failures or errors such as "failed to construct the join relation"). To fix, add code to check for the presence of such PHVs in relevant portions of the query tree. Notably, this required refactoring range_table_walker so that a caller could ask to walk individual RTEs not the whole list. (It might be a good idea to refactor range_table_mutator in the same way, if only to keep those functions looking similar; but I didn't do so here as it wasn't necessary for the bug fix.) This exercise also taught me that find_dependent_phvs(), as it stood, could only safely be used on the entire Query, not on subtrees. Adjust its API to reflect that; which in passing allows it to have a fast path for the common case of no PHVs anywhere. Per report from Will Leinweber. Back-patch to v12 where the bug was introduced. Discussion: https://postgr.es/m/CALLb-4xJMd4GZt2YCecMC95H-PafuWNKcmps4HLRx2NHNBfB4g@mail.gmail.com
* Add a reverse-translation column number array to struct AppendRelInfo.Tom Lane2019-12-02
| | | | | | | | | | | This provides for cheaper mapping of child columns back to parent columns. The one existing use-case in examine_simple_variable() would hardly justify this by itself; but an upcoming bug fix will make use of this array in a mainstream code path, and it seems likely that we'll find other uses for it as we continue to build out the partitioning infrastructure. Discussion: https://postgr.es/m/12424.1575168015@sss.pgh.pa.us
* Make the order of the header file includes consistent in backend modules.Amit Kapila2019-11-12
| | | | | | | | | | | Similar to commits 7e735035f2 and dddf4cdc33, this commit makes the order of header file inclusion consistent for backend modules. In the passing, removed a couple of duplicate inclusions. Author: Vignesh C Reviewed-by: Kuntal Ghosh and Amit Kapila Discussion: https://postgr.es/m/CALDaNm2Sznv8RR6Ex-iJO6xAdsxgWhCoETkaYX=+9DW3q0QCfA@mail.gmail.com
* Selectively include window frames in expression walks/mutates.Andrew Gierth2019-10-03
| | | | | | | | | | | | | | | | | | | | query_tree_walker and query_tree_mutator were skipping the windowClause of the query, without regard for the fact that the startOffset and endOffset in a WindowClause node are expression trees that need to be processed. This was an oversight in commit ec4be2ee6 from 2010 which added the expression fields; the main symptom is that function parameters in window frame clauses don't work in inlined functions. Fix (as conservatively as possible since this needs to not break existing out-of-tree callers) and add tests. Backpatch all the way, since this has been broken since 9.0. Per report from Alastair McKinley; fix by me with kibitzing and review from Tom Lane. Discussion: https://postgr.es/m/DB6PR0202MB2904E7FDDA9D81504D1E8C68E3800@DB6PR0202MB2904.eurprd02.prod.outlook.com
* Represent Lists as expansible arrays, not chains of cons-cells.Tom Lane2019-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Originally, Postgres Lists were a more or less exact reimplementation of Lisp lists, which consist of chains of separately-allocated cons cells, each having a value and a next-cell link. We'd hacked that once before (commit d0b4399d8) to add a separate List header, but the data was still in cons cells. That makes some operations -- notably list_nth() -- O(N), and it's bulky because of the next-cell pointers and per-cell palloc overhead, and it's very cache-unfriendly if the cons cells end up scattered around rather than being adjacent. In this rewrite, we still have List headers, but the data is in a resizable array of values, with no next-cell links. Now we need at most two palloc's per List, and often only one, since we can allocate some values in the same palloc call as the List header. (Of course, extending an existing List may require repalloc's to enlarge the array. But this involves just O(log N) allocations not O(N).) Of course this is not without downsides. The key difficulty is that addition or deletion of a list entry may now cause other entries to move, which it did not before. For example, that breaks foreach() and sister macros, which historically used a pointer to the current cons-cell as loop state. We can repair those macros transparently by making their actual loop state be an integer list index; the exposed "ListCell *" pointer is no longer state carried across loop iterations, but is just a derived value. (In practice, modern compilers can optimize things back to having just one loop state value, at least for simple cases with inline loop bodies.) In principle, this is a semantics change for cases where the loop body inserts or deletes list entries ahead of the current loop index; but I found no such cases in the Postgres code. The change is not at all transparent for code that doesn't use foreach() but chases lists "by hand" using lnext(). The largest share of such code in the backend is in loops that were maintaining "prev" and "next" variables in addition to the current-cell pointer, in order to delete list cells efficiently using list_delete_cell(). However, we no longer need a previous-cell pointer to delete a list cell efficiently. Keeping a next-cell pointer doesn't work, as explained above, but we can improve matters by changing such code to use a regular foreach() loop and then using the new macro foreach_delete_current() to delete the current cell. (This macro knows how to update the associated foreach loop's state so that no cells will be missed in the traversal.) There remains a nontrivial risk of code assuming that a ListCell * pointer will remain good over an operation that could now move the list contents. To help catch such errors, list.c can be compiled with a new define symbol DEBUG_LIST_MEMORY_USAGE that forcibly moves list contents whenever that could possibly happen. This makes list operations significantly more expensive so it's not normally turned on (though it is on by default if USE_VALGRIND is on). There are two notable API differences from the previous code: * lnext() now requires the List's header pointer in addition to the current cell's address. * list_delete_cell() no longer requires a previous-cell argument. These changes are somewhat unfortunate, but on the other hand code using either function needs inspection to see if it is assuming anything it shouldn't, so it's not all bad. Programmers should be aware of these significant performance changes: * list_nth() and related functions are now O(1); so there's no major access-speed difference between a list and an array. * Inserting or deleting a list element now takes time proportional to the distance to the end of the list, due to moving the array elements. (However, it typically *doesn't* require palloc or pfree, so except in long lists it's probably still faster than before.) Notably, lcons() used to be about the same cost as lappend(), but that's no longer true if the list is long. Code that uses lcons() and list_delete_first() to maintain a stack might usefully be rewritten to push and pop at the end of the list rather than the beginning. * There are now list_insert_nth...() and list_delete_nth...() functions that add or remove a list cell identified by index. These have the data-movement penalty explained above, but there's no search penalty. * list_concat() and variants now copy the second list's data into storage belonging to the first list, so there is no longer any sharing of cells between the input lists. The second argument is now declared "const List *" to reflect that it isn't changed. This patch just does the minimum needed to get the new implementation in place and fix bugs exposed by the regression tests. As suggested by the foregoing, there's a fair amount of followup work remaining to do. Also, the ENABLE_LIST_COMPAT macros are finally removed in this commit. Code using those should have been gone a dozen years ago. Patch by me; thanks to David Rowley, Jesper Pedersen, and others for review. Discussion: https://postgr.es/m/11587.1550975080@sss.pgh.pa.us
* Phase 2 pgindent run for v12.Tom Lane2019-05-22
| | | | | | | | | Switch to 2.1 version of pg_bsd_indent. This formats multiline function declarations "correctly", that is with additional lines of parameter declarations indented to match where the first line's left parenthesis is. Discussion: https://postgr.es/m/CAEepm=0P3FeTXRcU5B2W3jv3PgRVZ-kGUXLGfd42FFhUROO3ug@mail.gmail.com
* Refactor the representation of indexable clauses in IndexPaths.Tom Lane2019-02-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In place of three separate but interrelated lists (indexclauses, indexquals, and indexqualcols), an IndexPath now has one list "indexclauses" of IndexClause nodes. This holds basically the same information as before, but in a more useful format: in particular, there is now a clear connection between an indexclause (an original restriction clause from WHERE or JOIN/ON) and the indexquals (directly usable index conditions) derived from it. We also change the ground rules a bit by mandating that clause commutation, if needed, be done up-front so that what is stored in the indexquals list is always directly usable as an index condition. This gets rid of repeated re-determination of which side of the clause is the indexkey during costing and plan generation, as well as repeated lookups of the commutator operator. To minimize the added up-front cost, the typical case of commuting a plain OpExpr is handled by a new special-purpose function commute_restrictinfo(). For RowCompareExprs, generating the new clause properly commuted to begin with is not really any more complex than before, it's just different --- and we can save doing that work twice, as the pretty-klugy original implementation did. Tracking the connection between original and derived clauses lets us also track explicitly whether the derived clauses are an exact or lossy translation of the original. This provides a cheap solution to getting rid of unnecessary rechecks of boolean index clauses, which previously seemed like it'd be more expensive than it was worth. Another pleasant (IMO) side-effect is that EXPLAIN now always shows index clauses with the indexkey on the left; this seems less confusing. This commit leaves expand_indexqual_conditions() and some related functions in a slightly messy state. I didn't bother to change them any more than minimally necessary to work with the new data structure, because all that code is going to be refactored out of existence in a follow-on patch. Discussion: https://postgr.es/m/22182.1549124950@sss.pgh.pa.us
* Renaming for new subscripting mechanismAlvaro Herrera2019-02-01
| | | | | | | | | | | | Over at patch https://commitfest.postgresql.org/21/1062/ Dmitry wants to introduce a more generic subscription mechanism, which allows subscripting not only arrays but also other object types such as JSONB. That functionality is introduced in a largish invasive patch, out of which this internal renaming patch was extracted. Author: Dmitry Dolgov Reviewed-by: Tom Lane, Arthur Zakirov Discussion: https://postgr.es/m/CA+q6zcUK4EqPAu7XRRO5CCjMwhz5zvg+rfWuLzVoxp_5sKS6=w@mail.gmail.com
* Rename nodes/relation.h to nodes/pathnodes.h.Tom Lane2019-01-29
| | | | | | | | | | | | | The old name of this file was never a very good indication of what it was for. Now that there's also access/relation.h, we have a potential confusion hazard as well, so let's rename it to something more apropos. Per discussion, "pathnodes.h" is reasonable, since a good fraction of the file is Path node definitions. While at it, tweak a couple of other headers that were gratuitously importing relation.h into modules that don't need it. Discussion: https://postgr.es/m/7719.1548688728@sss.pgh.pa.us
* In the planner, replace an empty FROM clause with a dummy RTE.Tom Lane2019-01-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The fact that "SELECT expression" has no base relations has long been a thorn in the side of the planner. It makes it hard to flatten a sub-query that looks like that, or is a trivial VALUES() item, because the planner generally uses relid sets to identify sub-relations, and such a sub-query would have an empty relid set if we flattened it. prepjointree.c contains some baroque logic that works around this in certain special cases --- but there is a much better answer. We can replace an empty FROM clause with a dummy RTE that acts like a table of one row and no columns, and then there are no such corner cases to worry about. Instead we need some logic to get rid of useless dummy RTEs, but that's simpler and covers more cases than what was there before. For really trivial cases, where the query is just "SELECT expression" and nothing else, there's a hazard that adding the extra RTE makes for a noticeable slowdown; even though it's not much processing, there's not that much for the planner to do overall. However testing says that the penalty is very small, close to the noise level. In more complex queries, this is able to find optimizations that we could not find before. The new RTE type is called RTE_RESULT, since the "scan" plan type it gives rise to is a Result node (the same plan we produced for a "SELECT expression" query before). To avoid confusion, rename the old ResultPath path type to GroupResultPath, reflecting that it's only used in degenerate grouping cases where we know the query produces just one grouped row. (It wouldn't work to unify the two cases, because there are different rules about where the associated quals live during query_planner.) Note: although this touches readfuncs.c, I don't think a catversion bump is required, because the added case can't occur in stored rules, only plans. Patch by me, reviewed by David Rowley and Mark Dilger Discussion: https://postgr.es/m/15944.1521127664@sss.pgh.pa.us
* Split QTW_EXAMINE_RTES flag into QTW_EXAMINE_RTES_BEFORE/_AFTER.Tom Lane2019-01-25
| | | | | | | | | | | | | This change allows callers of query_tree_walker() to choose whether to visit an RTE before or after visiting the contents of the RTE (i.e., prefix or postfix tree order). All existing users of QTW_EXAMINE_RTES want the QTW_EXAMINE_RTES_BEFORE behavior, but an upcoming patch will want QTW_EXAMINE_RTES_AFTER, and it seems like a potentially useful change on its own. Andreas Karlsson (extracted from CTE inlining patch) Discussion: https://postgr.es/m/8810.1542402910@sss.pgh.pa.us
* Update copyright for 2019Bruce Momjian2019-01-02
| | | | Backpatch-through: certain files through 9.4
* Make type "name" collation-aware.Tom Lane2018-12-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The "name" comparison operators now all support collations, making them functionally equivalent to "text" comparisons, except for the different physical representation of the datatype. They do, in fact, mostly share the varstr_cmp and varstr_sortsupport infrastructure, which has been slightly enlarged to handle the case. To avoid changes in the default behavior of the datatype, set name's typcollation to C_COLLATION_OID not DEFAULT_COLLATION_OID, so that by default comparisons to a name value will continue to use strcmp semantics. (This would have been the case for system catalog columns anyway, because of commit 6b0faf723, but doing this makes it true for user-created name columns as well. In particular, this avoids locale-dependent changes in our regression test results.) In consequence, tweak a couple of places that made assumptions about collatable base types always having typcollation DEFAULT_COLLATION_OID. I have not, however, attempted to relax the restriction that user- defined collatable types must have that. Hence, "name" doesn't behave quite like a user-defined type; it acts more like a domain with COLLATE "C". (Conceivably, if we ever get rid of the need for catalog name columns to be fixed-length, "name" could actually become such a domain over text. But that'd be a pretty massive undertaking, and I'm not volunteering.) Discussion: https://postgr.es/m/15938.1544377821@sss.pgh.pa.us
* Add stack depth checks to key recursive functions in backend/nodes/*.c.Tom Lane2018-12-10
| | | | | | | | | | 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
* Revert MERGE patchSimon Riggs2018-04-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Support partition pruning at execution timeAlvaro Herrera2018-04-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Faster partition pruningAlvaro Herrera2018-04-06
| | | | | | | | | | | | | | | | | | | | | 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
* Improve parse representation for MERGESimon Riggs2018-04-06
| | | | | | | | | | | | 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
* WITH support in MERGESimon Riggs2018-04-03
| | | | | | Author: Peter Geoghegan Recursive support removed, no tests Docs added by me
* MERGE SQL Command following SQL:2016Simon Riggs2018-04-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Revert "Modified files for MERGE"Simon Riggs2018-04-02
| | | | This reverts commit 354f13855e6381d288dfaa52bcd4f2cb0fd4a5eb.
* Modified files for MERGESimon Riggs2018-04-02
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* Update copyright for 2018Bruce Momjian2018-01-02
| | | | Backpatch-through: certain files through 9.3
* Change TRUE/FALSE to true/falsePeter Eisentraut2017-11-08
| | | | | | | | | | | | | | The lower case spellings are C and C++ standard and are used in most parts of the PostgreSQL sources. The upper case spellings are only used in some files/modules. So standardize on the standard spellings. The APIs for ICU, Perl, and Windows define their own TRUE and FALSE, so those are left as is when using those APIs. In code comments, we use the lower-case spelling for the C concepts and keep the upper-case spelling for the SQL concepts. Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
* Support arrays over domains.Tom Lane2017-09-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Code review for NextValueExpr expression node type.Tom Lane2017-07-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Phase 3 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | Don't move parenthesized lines to the left, even if that means they flow past the right margin. By default, BSD indent lines up statement continuation lines that are within parentheses so that they start just to the right of the preceding left parenthesis. However, traditionally, if that resulted in the continuation line extending to the right of the desired right margin, then indent would push it left just far enough to not overrun the margin, if it could do so without making the continuation line start to the left of the current statement indent. That makes for a weird mix of indentations unless one has been completely rigid about never violating the 80-column limit. This behavior has been pretty universally panned by Postgres developers. Hence, disable it with indent's new -lpl switch, so that parenthesized lines are always lined up with the preceding left paren. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Phase 2 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Initial pgindent run with pg_bsd_indent version 2.0.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The new indent version includes numerous fixes thanks to Piotr Stefaniak. The main changes visible in this commit are: * Nicer formatting of function-pointer declarations. * No longer unexpectedly removes spaces in expressions using casts, sizeof, or offsetof. * No longer wants to add a space in "struct structname *varname", as well as some similar cases for const- or volatile-qualified pointers. * Declarations using PG_USED_FOR_ASSERTS_ONLY are formatted more nicely. * Fixes bug where comments following declarations were sometimes placed with no space separating them from the code. * Fixes some odd decisions for comments following case labels. * Fixes some cases where comments following code were indented to less than the expected column 33. On the less good side, it now tends to put more whitespace around typedef names that are not listed in typedefs.list. This might encourage us to put more effort into typedef name collection; it's not really a bug in indent itself. There are more changes coming after this round, having to do with comment indentation and alignment of lines appearing within parentheses. I wanted to limit the size of the diffs to something that could be reviewed without one's eyes completely glazing over, so it seemed better to split up the changes as much as practical. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Fix no-longer-valid shortcuts in expression_returns_set().Tom Lane2017-06-14
| | | | | | | | | | | | | | | expression_returns_set() used to short-circuit its recursion upon seeing certain node types, such as DistinctExpr, that it knew the executor did not support set-valued arguments for. That was never inherent, though, just a reflection of laziness in execQual.c. With the new implementation of SRFs there is no reason to think that any scalar-valued expression node could not have a set-valued subexpression, except for AggRefs and WindowFuncs where we know there is a parser check rejecting it. And indeed, the shortcut causes unexpected failures for cases such as a SRF underneath DistinctExpr, because the planner stops looking for SRFs too soon. Discussion: https://postgr.es/m/5259.1497044025@sss.pgh.pa.us
* Code review focused on new node types added by partitioning support.Tom Lane2017-05-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix failure to check that we got a plain Const from const-simplification of a coercion request. This is the cause of bug #14666 from Tian Bing: there is an int4 to money cast, but it's only stable not immutable (because of dependence on lc_monetary), resulting in a FuncExpr that the code was miserably unequipped to deal with, or indeed even to notice that it was failing to deal with. Add test cases around this coercion behavior. In view of the above, sprinkle the code liberally with castNode() macros, in hope of catching the next such bug a bit sooner. Also, change some functions that were randomly declared to take Node* to take more specific pointer types. And change some struct fields that were declared Node* but could be given more specific types, allowing removal of assorted explicit casts. Place PARTITION_MAX_KEYS check a bit closer to the code it's protecting. Likewise check only-one-key-for-list-partitioning restriction in a less random place. Avoid not-per-project-style usages like !strcmp(...). Fix assorted failures to avoid scribbling on the input of parse transformation. I'm not sure how necessary this is, but it's entirely silly for these functions to be expending cycles to avoid that and not getting it right. Add guards against partitioning on system columns. Put backend/nodes/ support code into an order that matches handling of these node types elsewhere. Annotate the fact that somebody added location fields to PartitionBoundSpec and PartitionRangeDatum but forgot to handle them in outfuncs.c/readfuncs.c. This is fairly harmless for production purposes (since readfuncs.c would just substitute -1 anyway) but it's still bogus. It's not worth forcing a post-beta1 initdb just to fix this, but if we have another reason to force initdb before 10.0, we should go back and clean this up. Contrariwise, somebody added location fields to PartitionElem and PartitionSpec but forgot to teach exprLocation() about them. Consolidate duplicative code in transformPartitionBound(). Improve a couple of error messages. Improve assorted commentary. Re-pgindent the files touched by this patch; this affects a few comment blocks that must have been added quite recently. Report: https://postgr.es/m/20170524024550.29935.14396@wrigleys.postgresql.org
* Post-PG 10 beta1 pgindent runBruce Momjian2017-05-17
| | | | perltidy run not included.
* Improve castNode notation by introducing list-extraction-specific variants.Tom Lane2017-04-10
| | | | | | | | | | | | | | | | | This extends the castNode() notation introduced by commit 5bcab1114 to provide, in one step, extraction of a list cell's pointer and coercion to a concrete node type. For example, "lfirst_node(Foo, lc)" is the same as "castNode(Foo, lfirst(lc))". Almost half of the uses of castNode that have appeared so far include a list extraction call, so this is pretty widely useful, and it saves a few more keystrokes compared to the old way. As with the previous patch, back-patch the addition of these macros to pg_list.h, so that the notation will be available when back-patching. Patch by me, after an idea of Andrew Gierth's. Discussion: https://postgr.es/m/14197.1491841216@sss.pgh.pa.us
* Identity columnsPeter Eisentraut2017-04-06
| | | | | | | | | | | | | This is the SQL standard-conforming variant of PostgreSQL's serial columns. It fixes a few usability issues that serial columns have: - CREATE TABLE / LIKE copies default but refers to same sequence - cannot add/drop serialness with ALTER TABLE - dropping default does not drop sequence - need to grant separate privileges to sequence - other slight weirdnesses because serial is some kind of special macro Reviewed-by: Vitaly Burovoy <vitaly.burovoy@gmail.com>
* Add infrastructure to support EphemeralNamedRelation references.Kevin Grittner2017-03-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A QueryEnvironment concept is added, which allows new types of objects to be passed into queries from parsing on through execution. At this point, the only thing implemented is a collection of EphemeralNamedRelation objects -- relations which can be referenced by name in queries, but do not exist in the catalogs. The only type of ENR implemented is NamedTuplestore, but provision is made to add more types fairly easily. An ENR can carry its own TupleDesc or reference a relation in the catalogs by relid. Although these features can be used without SPI, convenience functions are added to SPI so that ENRs can easily be used by code run through SPI. The initial use of all this is going to be transition tables in AFTER triggers, but that will be added to each PL as a separate commit. An incidental effect of this patch is to produce a more informative error message if an attempt is made to modify the contents of a CTE from a referencing DML statement. No tests previously covered that possibility, so one is added. Kevin Grittner and Thomas Munro Reviewed by Heikki Linnakangas, David Fetter, and Thomas Munro with valuable comments and suggestions from many others
* Support XMLTABLE query expressionAlvaro Herrera2017-03-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | XMLTABLE is defined by the SQL/XML standard as a feature that allows turning XML-formatted data into relational form, so that it can be used as a <table primary> in the FROM clause of a query. This new construct provides significant simplicity and performance benefit for XML data processing; what in a client-side custom implementation was reported to take 20 minutes can be executed in 400ms using XMLTABLE. (The same functionality was said to take 10 seconds using nested PostgreSQL XPath function calls, and 5 seconds using XMLReader under PL/Python). The implemented syntax deviates slightly from what the standard requires. First, the standard indicates that the PASSING clause is optional and that multiple XML input documents may be given to it; we make it mandatory and accept a single document only. Second, we don't currently support a default namespace to be specified. This implementation relies on a new executor node based on a hardcoded method table. (Because the grammar is fixed, there is no extensibility in the current approach; further constructs can be implemented on top of this such as JSON_TABLE, but they require changes to core code.) Author: Pavel Stehule, Álvaro Herrera Extensively reviewed by: Craig Ringer Discussion: https://postgr.es/m/CAFj8pRAgfzMD-LoSmnMGybD0WsEznLHWap8DO79+-GTRAPR4qA@mail.gmail.com
* Make more use of castNode()Peter Eisentraut2017-02-21
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* Update copyright via script for 2017Bruce Momjian2017-01-03
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* Implement table partitioning.Robert Haas2016-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Table partitioning is like table inheritance and reuses much of the existing infrastructure, but there are some important differences. The parent is called a partitioned table and is always empty; it may not have indexes or non-inherited constraints, since those make no sense for a relation with no data of its own. The children are called partitions and contain all of the actual data. Each partition has an implicit partitioning constraint. Multiple inheritance is not allowed, and partitioning and inheritance can't be mixed. Partitions can't have extra columns and may not allow nulls unless the parent does. Tuples inserted into the parent are automatically routed to the correct partition, so tuple-routing ON INSERT triggers are not needed. Tuple routing isn't yet supported for partitions which are foreign tables, and it doesn't handle updates that cross partition boundaries. Currently, tables can be range-partitioned or list-partitioned. List partitioning is limited to a single column, but range partitioning can involve multiple columns. A partitioning "column" can be an expression. Because table partitioning is less general than table inheritance, it is hoped that it will be easier to reason about properties of partitions, and therefore that this will serve as a better foundation for a variety of possible optimizations, including query planner optimizations. The tuple routing based which this patch does based on the implicit partitioning constraints is an example of this, but it seems likely that many other useful optimizations are also possible. Amit Langote, reviewed and tested by Robert Haas, Ashutosh Bapat, Amit Kapila, Rajkumar Raghuwanshi, Corey Huinker, Jaime Casanova, Rushabh Lathia, Erik Rijkers, among others. Minor revisions by me.
* Improve parsetree representation of special functions such as CURRENT_DATE.Tom Lane2016-08-16
| | | | | | | | | | | | | | We implement a dozen or so parameterless functions that the SQL standard defines special syntax for. Up to now, that was done by converting them into more or less ad-hoc constructs such as "'now'::text::date". That's messy for multiple reasons: it exposes what should be implementation details to users, and performance is worse than it needs to be in several cases. To improve matters, invent a new expression node type SQLValueFunction that can represent any of these parameterless functions. Bump catversion because this changes stored parsetrees for rules. Discussion: <30058.1463091294@sss.pgh.pa.us>
* Rethink node-level representation of partial-aggregation modes.Tom Lane2016-06-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | The original coding had three separate booleans representing partial aggregation behavior, which was confusing, unreadable, and error-prone, not least because the booleans weren't always listed in the same order. It was also inadequate for the allegedly-desirable future extension to support intermediate partial aggregation, because we'd need separate markers for serialization and deserialization in such a case. Merge these bools into an enum "AggSplit" to provide symbolic names for the supported operating modes (and document what those are). By assigning the values of the enum constants carefully, we can treat AggSplit values as options bitmasks so that tests of what to do aren't noticeably more expensive than before. While at it, get rid of Aggref.aggoutputtype. That's not needed since commit 59a3795c2 got rid of setrefs.c's special-purpose Aggref comparison code, and it likewise seemed more confusing than helpful. Assorted comment cleanup as well (there's still more that I want to do in that line). catversion bump for change in Aggref node contents. Should be the last one for partial-aggregation changes. Discussion: <29309.1466699160@sss.pgh.pa.us>
* Fix handling of argument and result datatypes for partial aggregation.Tom Lane2016-06-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When doing partial aggregation, the args list of the upper (combining) Aggref node is replaced by a Var representing the output of the partial aggregation steps, which has either the aggregate's transition data type or a serialized representation of that. However, nodeAgg.c blindly continued to use the args list as an indication of the user-level argument types. This broke resolution of polymorphic transition datatypes at executor startup (though it accidentally failed to fail for the ANYARRAY case, which is likely the only one anyone had tested). Moreover, the constructed FuncExpr passed to the finalfunc contained completely wrong information, which would have led to bogus answers or crashes for any case where the finalfunc examined that information (which is only likely to be with polymorphic aggregates using a non-polymorphic transition type). As an independent bug, apply_partialaggref_adjustment neglected to resolve a polymorphic transition datatype before assigning it as the output type of the lower-level Aggref node. This again accidentally failed to fail for ANYARRAY but would be unlikely to work in other cases. To fix the first problem, record the user-level argument types in a separate OID-list field of Aggref, and look to that rather than the args list when asking what the argument types were. (It turns out to be convenient to include any "direct" arguments in this list too, although those are not currently subject to being overwritten.) Rather than adding yet another resolve_aggregate_transtype() call to fix the second problem, add an aggtranstype field to Aggref, and store the resolved transition type OID there when the planner first computes it. (By doing this in the planner and not the parser, we can allow the aggregate's transition type to change from time to time, although no DDL support yet exists for that.) This saves nothing of consequence for simple non-polymorphic aggregates, but for polymorphic transition types we save a catalog lookup during executor startup as well as several planner lookups that are new in 9.6 due to parallel query planning. In passing, fix an error that was introduced into count_agg_clauses_walker some time ago: it was applying exprTypmod() to something that wasn't an expression node at all, but a TargetEntry. exprTypmod silently returned -1 so that there was not an obvious failure, but this broke the intended sensitivity of aggregate space consumption estimates to the typmod of varchar and similar data types. This part needs to be back-patched. Catversion bump due to change of stored Aggref nodes. Discussion: <8229.1466109074@sss.pgh.pa.us>
* Refactor to reduce code duplication for function property checking.Tom Lane2016-06-10
| | | | | | | | | | | | | | | | | | | | | | | As noted by Andres Freund, we'd accumulated quite a few similar functions in clauses.c that examine all functions in an expression tree to see if they satisfy some boolean test. Reduce the duplication by inventing a function check_functions_in_node() that applies a simple callback function to each SQL function OID appearing in a given expression node. This also fixes some arguable oversights; for example, contain_mutable_functions() did not check aggregate or window functions for mutability. I doubt that that represents a live bug at the moment, because we don't really consider mutability for aggregates; but it might someday be one. I chose to put check_functions_in_node() in nodeFuncs.c because it seemed like other modules might wish to use it in future. That in turn forced moving set_opfuncid() et al into nodeFuncs.c, as the alternative was for nodeFuncs.c to depend on optimizer/setrefs.c which didn't seem very clean. In passing, teach contain_leaked_vars_walker() about a few more expression node types it can safely look through, and improve the rather messy and undercommented code in has_parallel_hazard_walker(). Discussion: <20160527185853.ziol2os2zskahl7v@alap3.anarazel.de>
* pgindent run for 9.6Robert Haas2016-06-09
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* Support IndexElem in raw_expression_tree_walker().Tom Lane2016-05-23
| | | | | | | | | Needed for cases in which INSERT ... ON CONFLICT appears inside a recursive CTE item. Per bug #14153 from Thomas Alton. Patch by Peter Geoghegan, slightly adjusted by me Report: <20160521232802.22598.13537@wrigleys.postgresql.org>