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* Implement SEMI and ANTI joins in the planner and executor. (Semijoins replaceTom Lane2008-08-14
| | | | | | | | | | | | | | the old JOIN_IN code, but antijoins are new functionality.) Teach the planner to convert appropriate EXISTS and NOT EXISTS subqueries into semi and anti joins respectively. Also, LEFT JOINs with suitable upper-level IS NULL filters are recognized as being anti joins. Unify the InClauseInfo and OuterJoinInfo infrastructure into "SpecialJoinInfo". With that change, it becomes possible to associate a SpecialJoinInfo with every join attempt, which permits some cleanup of join selectivity estimation. That needs to be taken much further than this patch does, but the next step is to change the API for oprjoin selectivity functions, which seems like material for a separate patch. So for the moment the output size estimates for semi and especially anti joins are quite bogus.
* Improve INTERSECT/EXCEPT hashing by realizing that we don't need to make anyTom Lane2008-08-07
| | | | | | | | | hashtable entries for tuples that are found only in the second input: they can never contribute to the output. Furthermore, this implies that the planner should endeavor to put first the smaller (in number of groups) input relation for an INTERSECT. Implement that, and upgrade prepunion's estimation of the number of rows returned by setops so that there's some amount of sanity in the estimate of which one is smaller.
* Support hashing for duplicate-elimination in INTERSECT and EXCEPT queries.Tom Lane2008-08-07
| | | | | | | | | | This completes my project of improving usage of hashing for duplicate elimination (aggregate functions with DISTINCT remain undone, but that's for some other day). As with the previous patches, this means we can INTERSECT/EXCEPT on datatypes that can hash but not sort, and it means that INTERSECT/EXCEPT without ORDER BY are no longer certain to produce sorted output.
* Teach the system how to use hashing for UNION. (INTERSECT/EXCEPT will follow,Tom Lane2008-08-07
| | | | | | | | | | | but seem like a separate patch since most of the remaining work is on the executor side.) I took the opportunity to push selection of the grouping operators for set operations into the parser where it belongs. Otherwise this is just a small exercise in making prepunion.c consider both alternatives. As with the recent DISTINCT patch, this means we can UNION on datatypes that can hash but not sort, and it means that UNION without ORDER BY is no longer certain to produce sorted output.
* Rearrange the querytree representation of ORDER BY/GROUP BY/DISTINCT itemsTom Lane2008-08-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | as per my recent proposal: 1. Fold SortClause and GroupClause into a single node type SortGroupClause. We were already relying on them to be struct-equivalent, so using two node tags wasn't accomplishing much except to get in the way of comparing items with equal(). 2. Add an "eqop" field to SortGroupClause to carry the associated equality operator. This is cheap for the parser to get at the same time it's looking up the sort operator, and storing it eliminates the need for repeated not-so-cheap lookups during planning. In future this will also let us represent GROUP/DISTINCT operations on datatypes that have hash opclasses but no btree opclasses (ie, they have equality but no natural sort order). The previous representation simply didn't work for that, since its only indicator of comparison semantics was a sort operator. 3. Add a hasDistinctOn boolean to struct Query to explicitly record whether the distinctClause came from DISTINCT or DISTINCT ON. This allows removing some complicated and not 100% bulletproof code that attempted to figure that out from the distinctClause alone. This patch doesn't in itself create any new capability, but it's necessary infrastructure for future attempts to use hash-based grouping for DISTINCT and UNION/INTERSECT/EXCEPT.
* Support "variadic" functions, which can accept a variable number of argumentsTom Lane2008-07-16
| | | | | | | | | | | | | | so long as all the trailing arguments are of the same (non-array) type. The function receives them as a single array argument (which is why they have to all be the same type). It might be useful to extend this facility to aggregates, but this patch doesn't do that. This patch imposes a noticeable slowdown on function lookup --- a follow-on patch will fix that by adding a redundant column to pg_proc. Pavel Stehule
* Add a RESTART (without parameter) option to ALTER SEQUENCE, allowing aTom Lane2008-05-16
| | | | | | | | | | | | | | sequence to be reset to its original starting value. This requires adding the original start value to the set of parameters (columns) of a sequence object, which is a user-visible change with potential compatibility implications; it also forces initdb. Also add hopefully-SQL-compatible RESTART/CONTINUE IDENTITY options to TRUNCATE TABLE. RESTART IDENTITY executes ALTER SEQUENCE RESTART for all sequences "owned by" any of the truncated relations. CONTINUE IDENTITY is a no-op option. Zoltan Boszormenyi
* Remove typename from A_Const.Alvaro Herrera2008-04-29
| | | | Brendan Jurd, minor editorialization by me.
* Push index operator lossiness determination down to GIST/GIN opclassTom Lane2008-04-14
| | | | | | | | | | | "consistent" functions, and remove pg_amop.opreqcheck, as per recent discussion. The main immediate benefit of this is that we no longer need 8.3's ugly hack of requiring @@@ rather than @@ to test weight-using tsquery searches on GIN indexes. In future it should be possible to optimize some other queries better than is done now, by detecting at runtime whether the index match is exact or not. Tom Lane, after an idea of Heikki's, and with some help from Teodor.
* Since createplan.c no longer cares whether index operators are lossy, it hasTom Lane2008-04-13
| | | | | | | | | | no particular need to do get_op_opfamily_properties() while building an indexscan plan. Postpone that lookup until executor start. This simplifies createplan.c a lot more than it complicates nodeIndexscan.c, and makes things more uniform since we already had to do it that way for RowCompare expressions. Should be a bit faster too, at least for plans that aren't re-used many times, since we avoid palloc'ing and perhaps copying the intermediate list data structure.
* Remove TypeName struct's timezone flag, which has been write-only storageTom Lane2008-03-21
| | | | | for a very long time --- in current usage it's entirely redundant with the name field.
* Arrange for an explicit cast applied to an ARRAY[] constructor to be appliedTom Lane2008-03-20
| | | | | | | | | | directly to all the member expressions, instead of the previous implementation where the ARRAY[] constructor would infer a common element type and then we'd coerce the finished array after the fact. This has a number of benefits, one being that we can allow an empty ARRAY[] construct so long as its element type is specified by such a cast. Brendan Jurd, minor fixes by me.
* Add missing copyfuncs/equalfuncs support for AlterTSDictionaryStmt andTom Lane2008-02-07
| | | | | | | AlterTSConfigurationStmt. All utility statement node types are expected to be supported here, though they do not have to have outfuncs/readfuncs support. Found by running regression tests with COPY_PARSE_PLAN_TREES enabled.
* Update copyrights in source tree to 2008.Bruce Momjian2008-01-01
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* Code review for LIKE ... INCLUDING INDEXES patch. Fix failure to propagateTom Lane2007-12-01
| | | | | | | | | | constraint status of copied indexes (bug #3774), as well as various other small bugs such as failure to pstrdup when needed. Allow INCLUDING INDEXES indexes to be merged with identical declared indexes (perhaps not real useful, but the code is there and having it not apply to LIKE indexes seems pretty unorthogonal). Avoid useless work in generateClonedIndexStmt(). Undo some poorly chosen API changes, and put a couple of routines in modules that seem to be better places for them.
* Re-run pgindent with updated list of typedefs. (Updated README shouldBruce Momjian2007-11-15
| | | | avoid this problem in the future.)
* pgindent run for 8.3.Bruce Momjian2007-11-15
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* Fix the plan-invalidation mechanism to treat regclass constants that refer toTom Lane2007-10-11
| | | | | | | | | | a relation as a reason to invalidate a plan when the relation changes. This handles scenarios such as dropping/recreating a sequence that is referenced by nextval('seq') in a cached plan. Rather than teach plancache.c all about digging through plan trees to find regclass Consts, we charge the planner's setrefs.c with making a list of the relation OIDs on which each plan depends. That way the list can be built cheaply during a plan tree traversal that has to happen anyway. Per bug #3662 and subsequent discussion.
* Support SET FROM CURRENT in CREATE/ALTER FUNCTION, ALTER DATABASE, ALTER ROLE.Tom Lane2007-09-03
| | | | | | | (Actually, it works as a plain statement too, but I didn't document that because it seems a bit useless.) Unify VariableResetStmt with VariableSetStmt, and clean up some ancient cruft in the representation of same.
* Rewrite make_outerjoininfo's construction of min_lefthand and min_righthandTom Lane2007-08-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | sets for outer joins, in the light of bug #3588 and additional thought and experimentation. The original methodology was fatally flawed for nests of more than two outer joins: it got the relationships between adjacent joins right, but didn't always come to the right conclusions about whether a join could be interchanged with one two or more levels below it. This was largely caused by a mistaken idea that we should use the min_lefthand + min_righthand sets of a sub-join as the minimum left or right input set of an upper join when we conclude that the sub-join can't commute with the upper one. If there's a still-lower join that the sub-join *can* commute with, this method led us to think that that one could commute with the topmost join; which it can't. Another problem (not directly connected to bug #3588) was that make_outerjoininfo's processing-order-dependent method for enforcing outer join identity #3 didn't work right: if we decided that join A could safely commute with lower join B, we dropped all information about sub-joins under B that join A could perhaps not safely commute with, because we removed B's entire min_righthand from A's. To fix, make an explicit computation of all inner join combinations that occur below an outer join, and add to that the full syntactic relsets of any lower outer joins that we determine it can't commute with. This method gives much more direct enforcement of the outer join rearrangement identities, and it turns out not to cost a lot of additional bookkeeping. Thanks to Richard Harris for the bug report and test case.
* Implement CREATE TABLE LIKE ... INCLUDING INDEXES. Patch from NikhilS,Neil Conway2007-07-17
| | | | | based in part on an earlier patch from Trevor Hardcastle, and reviewed by myself.
* Improve UPDATE/DELETE WHERE CURRENT OF so that they can be used from plpgsqlTom Lane2007-06-11
| | | | | | | with a plpgsql-defined cursor. The underlying mechanism for this is that the main SQL engine will now take "WHERE CURRENT OF $n" where $n is a refcursor parameter. Not sure if we should document that fact or consider it an implementation detail. Per discussion with Pavel Stehule.
* Support UPDATE/DELETE WHERE CURRENT OF cursor_name, per SQL standard.Tom Lane2007-06-11
| | | | | | | | | Along the way, allow FOR UPDATE in non-WITH-HOLD cursors; there may once have been a reason to disallow that, but it seems to work now, and it's really rather necessary if you want to select a row via a cursor and then update it in a concurrent-safe fashion. Original patch by Arul Shaji, rather heavily editorialized by Tom Lane.
* Downgrade implicit casts to text to be assignment-only, except for the onesTom Lane2007-06-05
| | | | | | | | | | | | | | | | | | | | | | | | | from the other string-category types; this eliminates a lot of surprising interpretations that the parser could formerly make when there was no directly applicable operator. Create a general mechanism that supports casts to and from the standard string types (text,varchar,bpchar) for *every* datatype, by invoking the datatype's I/O functions. These new casts are assignment-only in the to-string direction, explicit-only in the other, and therefore should create no surprising behavior. Remove a bunch of thereby-obsoleted datatype-specific casting functions. The "general mechanism" is a new expression node type CoerceViaIO that can actually convert between *any* two datatypes if their external text representations are compatible. This is more general than needed for the immediate feature, but might be useful in plpgsql or other places in future. This commit does nothing about the issue that applying the concatenation operator || to non-text types will now fail, often with strange error messages due to misinterpreting the operator as array concatenation. Since it often (not always) worked before, we should either make it succeed or at least give a more user-friendly error; but details are still under debate. Peter Eisentraut and Tom Lane
* Repair planner bug introduced in 8.2 by ability to rearrange outer joins:Tom Lane2007-05-22
| | | | | | | | | | | | | | | | | | | in cases where a sub-SELECT inserts a WHERE clause between two outer joins, that clause may prevent us from re-ordering the two outer joins. The code was considering only the joins' own ON-conditions in determining reordering safety, which is not good enough. Add a "delay_upper_joins" flag to OuterJoinInfo to flag that we have detected such a clause and higher-level outer joins shouldn't be permitted to commute with this one. (This might seem overly coarse, but given the current rules for OJ reordering, it's sufficient AFAICT.) The failure case is actually pretty narrow: it needs a WHERE clause within the RHS of a left join that checks the RHS of a lower left join, but is not strict for that RHS (else we'd have simplified the lower join to a plain join). Even then no failure will be manifest unless the planner chooses to rearrange the join order. Per bug report from Adam Terrey.
* Modify processing of DECLARE CURSOR and EXPLAIN so that they can resolve theTom Lane2007-04-27
| | | | | | | | | | | | | | types of unspecified parameters when submitted via extended query protocol. This worked in 8.2 but I had broken it during plancache changes. DECLARE CURSOR is now treated almost exactly like a plain SELECT through parse analysis, rewrite, and planning; only just before sending to the executor do we divert it away to ProcessUtility. This requires a special-case check in a number of places, but practically all of them were already special-casing SELECT INTO, so it's not too ugly. (Maybe it would be a good idea to merge the two by treating IntoClause as a form of utility statement? Not going to worry about that now, though.) That approach doesn't work for EXPLAIN, however, so for that I punted and used a klugy solution of running parse analysis an extra time if under extended query protocol.
* Rename the newly-added commands for discarding session state.Neil Conway2007-04-26
| | | | | | | | RESET SESSION, RESET PLANS, and RESET TEMP are now DISCARD ALL, DISCARD PLANS, and DISCARD TEMP, respectively. This is to avoid confusion with the pre-existing RESET variants: the DISCARD commands are not actually similar to RESET. Patch from Marko Kreen, with some minor editorialization.
* Support enum data types. Along the way, use macros for the values ofTom Lane2007-04-02
| | | | | pg_type.typtype whereever practical. Tom Dunstan, with some kibitzing from Tom Lane.
* Fix array coercion expressions to ensure that the correct volatility isTom Lane2007-03-27
| | | | | | | | | seen by code inspecting the expression. The best way to do this seems to be to drop the original representation as a function invocation, and instead make a special expression node type that represents applying the element-type coercion function to each array element. In this way the element function is exposed and will be checked for volatility. Per report from Guillaume Smet.
* Fix up the remaining places where the expression node structure would loseTom Lane2007-03-17
| | | | | | | | | | | | | | available information about the typmod of an expression; namely, Const, ArrayRef, ArrayExpr, and EXPR and ARRAY SubLinks. In the ArrayExpr and SubLink cases it wasn't really the data structure's fault, but exprTypmod() being lazy. This seems like a good idea in view of the expected increase in typmod usage from Teodor's work to allow user-defined types to have typmods. In particular this responds to the concerns we had about eliminating the special-purpose hack that exprTypmod() used to have for BPCHAR Consts. We can now tell whether or not such a Const has been cast to a specific length, and report or display properly if so. initdb forced due to changes in stored rules.
* First phase of plan-invalidation project: create a plan cache managementTom Lane2007-03-13
| | | | | | | | | | | | | | | | module and teach PREPARE and protocol-level prepared statements to use it. In service of this, rearrange utility-statement processing so that parse analysis does not assume table schemas can't change before execution for utility statements (necessary because we don't attempt to re-acquire locks for utility statements when reusing a stored plan). This requires some refactoring of the ProcessUtility API, but it ends up cleaner anyway, for instance we can get rid of the QueryContext global. Still to do: fix up SPI and related code to use the plan cache; I'm tempted to try to make SQL functions use it too. Also, there are at least some aspects of system state that we want to ensure remain the same during a replan as in the original processing; search_path certainly ought to behave that way for instance, and perhaps there are others.
* Get rid of the separate EState for subplans, and just let them share theTom Lane2007-02-27
| | | | | | | | | parent query's EState. Now that there's a single flat rangetable for both the main plan and subplans, there's no need anymore for a separate EState, and removing it allows cleaning up some crufty code in nodeSubplan.c and nodeSubqueryscan.c. Should be a tad faster too, although any difference will probably be hard to measure. This is the last bit of subsidiary mop-up work from changing to a flat rangetable.
* Turn the rangetable used by the executor into a flat list, and avoid storingTom Lane2007-02-22
| | | | | | | | | | | | | | | | | useless substructure for its RangeTblEntry nodes. (I chose to keep using the same struct node type and just zero out the link fields for unneeded info, rather than making a separate ExecRangeTblEntry type --- it seemed too fragile to have two different rangetable representations.) Along the way, put subplans into a list in the toplevel PlannedStmt node, and have SubPlan nodes refer to them by list index instead of direct pointers. Vadim wanted to do that years ago, but I never understood what he was on about until now. It makes things a *whole* lot more robust, because we can stop worrying about duplicate processing of subplans during expression tree traversals. That's been a constant source of bugs, and it's finally gone. There are some consequent simplifications yet to be made, like not using a separate EState for subplans in the executor, but I'll tackle that later.
* Remove the Query structure from the executor's API. This allows us to stopTom Lane2007-02-20
| | | | | | | | | | | | | | | storing mostly-redundant Query trees in prepared statements, portals, etc. To replace Query, a new node type called PlannedStmt is inserted by the planner at the top of a completed plan tree; this carries just the fields of Query that are still needed at runtime. The statement lists kept in portals etc. now consist of intermixed PlannedStmt and bare utility-statement nodes --- no Query. This incidentally allows us to remove some fields from Query and Plan nodes that shouldn't have been there in the first place. Still to do: simplify the execution-time range table; at the moment the range table passed to the executor still contains Query trees for subqueries. initdb forced due to change of stored rules.
* Put function expressions and values lists into FunctionScan and ValuesScanTom Lane2007-02-19
| | | | | | plan nodes, so that the executor does not need to get these items from the range table at runtime. This will avoid needing to include these fields in the compact range table I'm expecting to make the executor use.
* Implement XMLSERIALIZE for real. Analogously, make the xml to text castPeter Eisentraut2007-02-03
| | | | | | | | | observe the xmloption. Reorganize the representation of the XML option in the parse tree and the API to make it easier to manage and understand. Add regression tests for parsing back XML expressions.
* Add CREATE/ALTER/DROP OPERATOR FAMILY commands, also COMMENT ON OPERATORTom Lane2007-01-23
| | | | | | FAMILY; and add FAMILY option to CREATE OPERATOR CLASS to allow adding a class to a pre-existing family. Per previous discussion. Man, what a tedious lot of cutting and pasting ...
* Put back planner's ability to cache the results of mergejoinscansel(),Tom Lane2007-01-22
| | | | | | | | | | which I had removed in the first cut of the EquivalenceClass rewrite to simplify that patch a little. But it's still important --- in a four-way join problem mergejoinscansel() was eating about 40% of the planning time according to gprof. Also, improve the EquivalenceClass code to re-use join RestrictInfos rather than generating fresh ones for each join considered. This saves some memory space but more importantly improves the effectiveness of caching planning info in RestrictInfos.
* Refactor planner's pathkeys data structure to create a separate, explicitTom Lane2007-01-20
| | | | | | | | | | | | | | representation of equivalence classes of variables. This is an extensive rewrite, but it brings a number of benefits: * planner no longer fails in the presence of "incomplete" operator families that don't offer operators for every possible combination of datatypes. * avoid generating and then discarding redundant equality clauses. * remove bogus assumption that derived equalities always use operators named "=". * mergejoins can work with a variety of sort orders (e.g., descending) now, instead of tying each mergejoinable operator to exactly one sort order. * better recognition of redundant sort columns. * can make use of equalities appearing underneath an outer join.
* Change the planner-to-executor API so that the planner tells the executorTom Lane2007-01-10
| | | | | | | | | | | | | | | | which comparison operators to use for plan nodes involving tuple comparison (Agg, Group, Unique, SetOp). Formerly the executor looked up the default equality operator for the datatype, which was really pretty shaky, since it's possible that the data being fed to the node is sorted according to some nondefault operator class that could have an incompatible idea of equality. The planner knows what it has sorted by and therefore can provide the right equality operator to use. Also, this change moves a couple of catalog lookups out of the executor and into the planner, which should help startup time for pre-planned queries by some small amount. Modify the planner to remove some other cavalier assumptions about always being able to use the default operators. Also add "nulls first/last" info to the Plan node for a mergejoin --- neither the executor nor the planner can cope yet, but at least the API is in place.
* Support ORDER BY ... NULLS FIRST/LAST, and add ASC/DESC/NULLS FIRST/NULLS LASTTom Lane2007-01-09
| | | | | | | | | | | | per-column options for btree indexes. The planner's support for this is still pretty rudimentary; it does not yet know how to plan mergejoins with nondefault ordering options. The documentation is pretty rudimentary, too. I'll work on improving that stuff later. Note incompatible change from prior behavior: ORDER BY ... USING will now be rejected if the operator is not a less-than or greater-than member of some btree opclass. This prevents less-than-sane behavior if an operator that doesn't actually define a proper sort ordering is selected.
* Update CVS HEAD for 2007 copyright. Back branches are typically notBruce Momjian2007-01-05
| | | | back-stamped for this.
* Support type modifiers for user-defined types, and pull most knowledgeTom Lane2006-12-30
| | | | | | about typmod representation for standard types out into type-specific typmod I/O functions. Teodor Sigaev, with some editorialization by Tom Lane.
* Code review for XML patch. Instill a bit of sanity in the location ofTom Lane2006-12-24
| | | | | | | the XmlExpr code in various lists, use a representation that has some hope of reverse-listing correctly (though it's still a de-escaping function shy of correctness), generally try to make it look more like Postgres coding conventions.
* Restructure operator classes to allow improved handling of cross-data-typeTom Lane2006-12-23
| | | | | | | | | | | | | | | | cases. Operator classes now exist within "operator families". While most families are equivalent to a single class, related classes can be grouped into one family to represent the fact that they are semantically compatible. Cross-type operators are now naturally adjunct parts of a family, without having to wedge them into a particular opclass as we had done originally. This commit restructures the catalogs and cleans up enough of the fallout so that everything still works at least as well as before, but most of the work needed to actually improve the planner's behavior will come later. Also, there are not yet CREATE/DROP/ALTER OPERATOR FAMILY commands; the only way to create a new family right now is to allow CREATE OPERATOR CLASS to make one by default. I owe some more documentation work, too. But that can all be done in smaller pieces once this infrastructure is in place.
* Initial SQL/XML support: xml data type and initial set of functions.Peter Eisentraut2006-12-21
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* Add a paramtypmod field to Param nodes. This is dead weight for ParamsTom Lane2006-12-10
| | | | | | | | | | representing externally-supplied values, since the APIs that carry such values only specify type not typmod. However, for PARAM_SUBLINK Params it is handy to carry the typmod of the sublink's output column. This is a much cleaner solution for the recently reported 'could not find pathkey item to sort' and 'failed to find unique expression in subplan tlist' bugs than my original 8.2-compatible patch. Besides, someday we might want to support typmods for external parameters ...
* Fix recently-understood problems with handling of XID freezing, particularlyTom Lane2006-11-05
| | | | | | | | | | | | | | | in PITR scenarios. We now WAL-log the replacement of old XIDs with FrozenTransactionId, so that such replacement is guaranteed to propagate to PITR slave databases. Also, rather than relying on hint-bit updates to be preserved, pg_clog is not truncated until all instances of an XID are known to have been replaced by FrozenTransactionId. Add new GUC variables and pg_autovacuum columns to allow management of the freezing policy, so that users can trade off the size of pg_clog against the amount of freezing work done. Revise the already-existing code that forces autovacuum of tables approaching the wraparound point to make it more bulletproof; also, revise the autovacuum logic so that anti-wraparound vacuuming is done per-table rather than per-database. initdb forced because of changes in pg_class, pg_database, and pg_autovacuum catalogs. Heikki Linnakangas, Simon Riggs, and Tom Lane.
* Code and docs review for ALTER TABLE INHERIT/NO INHERIT patch.Tom Lane2006-10-13
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* pgindent run for 8.2.Bruce Momjian2006-10-04
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