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* Split CollateClause into separate raw and analyzed node types.Tom Lane2011-03-11
| | | | | | | | | | | CollateClause is now used only in raw grammar output, and CollateExpr after parse analysis. This is for clarity and to avoid carrying collation names in post-analysis parse trees: that's both wasteful and possibly misleading, since the collation's name could be changed while the parsetree still exists. Also, clean up assorted infelicities and omissions in processing of the node type.
* Remove collation information from TypeName, where it does not belong.Tom Lane2011-03-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The initial collations patch treated a COLLATE spec as part of a TypeName, following what can only be described as brain fade on the part of the SQL committee. It's a lot more reasonable to treat COLLATE as a syntactically separate object, so that it can be added in only the productions where it actually belongs, rather than needing to reject it in a boatload of places where it doesn't belong (something the original patch mostly failed to do). In addition this change lets us meet the spec's requirement to allow COLLATE anywhere in the clauses of a ColumnDef, and it avoids unfriendly behavior for constructs such as "foo::type COLLATE collation". To do this, pull collation information out of TypeName and put it in ColumnDef instead, thus reverting most of the collation-related changes in parse_type.c's API. I made one additional structural change, which was to use a ColumnDef as an intermediate node in AT_AlterColumnType AlterTableCmd nodes. This provides enough room to get rid of the "transform" wart in AlterTableCmd too, since the ColumnDef can carry the USING expression easily enough. Also fix some other minor bugs that have crept in in the same areas, like failure to copy recently-added fields of ColumnDef in copyfuncs.c. While at it, document the formerly secret ability to specify a collation in ALTER TABLE ALTER COLUMN TYPE, ALTER TYPE ADD ATTRIBUTE, and ALTER TYPE ALTER ATTRIBUTE TYPE; and correct some misstatements about what the default collation selection will be when COLLATE is omitted. BTW, the three-parameter form of format_type() should go away too, since it just contributes to the confusion in this area; but I'll do that in a separate patch.
* Allow non-superusers to create (some) extensions.Tom Lane2011-03-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the unconditional superuser permissions check in CREATE EXTENSION, and instead define a "superuser" extension property, which when false (not the default) skips the superuser permissions check. In this case the calling user only needs enough permissions to execute the commands in the extension's installation script. The superuser property is also enforced in the same way for ALTER EXTENSION UPDATE cases. In other ALTER EXTENSION cases and DROP EXTENSION, test ownership of the extension rather than superuserness. ALTER EXTENSION ADD/DROP needs to insist on ownership of the target object as well; to do that without duplicating code, refactor comment.c's big switch for permissions checks into a separate function in objectaddress.c. I also removed the superuserness checks in pg_available_extensions and related functions; there's no strong reason why everybody shouldn't be able to see that info. Also invent an IF NOT EXISTS variant of CREATE EXTENSION, and use that in pg_dump, so that dumps won't fail for installed-by-default extensions. We don't have any of those yet, but we will soon. This is all per discussion of wrapping the standard procedural languages into extensions. I'll make those changes in a separate commit; this is just putting the core infrastructure in place.
* Support data-modifying commands (INSERT/UPDATE/DELETE) in WITH.Tom Lane2011-02-25
| | | | | | | | | | | | | | This patch implements data-modifying WITH queries according to the semantics that the updates all happen with the same command counter value, and in an unspecified order. Therefore one WITH clause can't see the effects of another, nor can the outer query see the effects other than through the RETURNING values. And attempts to do conflicting updates will have unpredictable results. We'll need to document all that. This commit just fixes the code; documentation updates are waiting on author. Marko Tiikkaja and Hitoshi Harada
* Add a relkind field to RangeTblEntry to avoid some syscache lookups.Tom Lane2011-02-22
| | | | | | | | | The recent additions for FDW support required checking foreign-table-ness in several places in the parse/plan chain. While it's not clear whether that would really result in a noticeable slowdown, it seems best to avoid any performance risk by keeping a copy of the relation's relkind in RangeTblEntry. That might have some other uses later, anyway. Per discussion.
* Implement an API to let foreign-data wrappers actually be functional.Tom Lane2011-02-20
| | | | | | | This commit provides the core code and documentation needed. A contrib module test case will follow shortly. Shigeru Hanada, Jan Urbanski, Heikki Linnakangas
* Create the catalog infrastructure for foreign-data-wrapper handlers.Tom Lane2011-02-19
| | | | | | | | | | | | | | | Add a fdwhandler column to pg_foreign_data_wrapper, plus HANDLER options in the CREATE FOREIGN DATA WRAPPER and ALTER FOREIGN DATA WRAPPER commands, plus pg_dump support for same. Also invent a new pseudotype fdw_handler with properties similar to language_handler. This is split out of the "FDW API" patch for ease of review; it's all stuff we will certainly need, regardless of any other details of the FDW API. FDW handler functions will not actually get called yet. In passing, fix some omissions and infelicities in foreigncmds.c. Shigeru Hanada, Jan Urbanski, Heikki Linnakangas
* Add support for multiple versions of an extension and ALTER EXTENSION UPDATE.Tom Lane2011-02-11
| | | | | | | | | | | This follows recent discussions, so it's quite a bit different from Dimitri's original. There will probably be more changes once we get a bit of experience with it, but let's get it in and start playing with it. This is still just core code. I'll start converting contrib modules shortly. Dimitri Fontaine and Tom Lane
* Extend "ALTER EXTENSION ADD object" to permit "DROP object" as well.Tom Lane2011-02-10
| | | | | Per discussion, this is something we should have sooner rather than later, and it doesn't take much additional code to support it.
* Fix improper matching of resjunk column names for FOR UPDATE in subselect.Tom Lane2011-02-09
| | | | | | | | | | | | | | | | Flattening of subquery range tables during setrefs.c could lead to the rangetable indexes in PlanRowMark nodes not matching up with the column names previously assigned to the corresponding resjunk ctid (resp. tableoid or wholerow) columns. Typical symptom would be either a "cannot extract system attribute from virtual tuple" error or an Assert failure. This wasn't a problem before 9.0 because we didn't support FOR UPDATE below the top query level, and so the final flattening could never renumber an RTE that was relevant to FOR UPDATE. Fix by using a plan-tree-wide unique number for each PlanRowMark to label the associated resjunk columns, so that the number need not change during flattening. Per report from David Johnston (though I'm darned if I can see how this got past initial testing of the relevant code). Back-patch to 9.0.
* Implement "ALTER EXTENSION ADD object".Tom Lane2011-02-09
| | | | | | | | | | | This is an essential component of making the extension feature usable; first because it's needed in the process of converting an existing installation containing "loose" objects of an old contrib module into the extension-based world, and second because we'll have to use it in pg_dump --binary-upgrade, as per recent discussion. Loosely based on part of Dimitri Fontaine's ALTER EXTENSION UPGRADE patch.
* Core support for "extensions", which are packages of SQL objects.Tom Lane2011-02-08
| | | | | | | | | | | | | This patch adds the server infrastructure to support extensions. There is still one significant loose end, namely how to make it play nice with pg_upgrade, so I am not yet committing the changes that would make all the contrib modules depend on this feature. In passing, fix a disturbingly large amount of breakage in AlterObjectNamespace() and callers. Dimitri Fontaine, reviewed by Anssi Kääriäinen, Itagaki Takahiro, Tom Lane, and numerous others
* Per-column collation supportPeter Eisentraut2011-02-08
| | | | | | | | This adds collation support for columns and domains, a COLLATE clause to override it per expression, and B-tree index support. Peter Eisentraut reviewed by Pavel Stehule, Itagaki Takahiro, Robert Haas, Noah Misch
* Implement ALTER TABLE ADD UNIQUE/PRIMARY KEY USING INDEX.Tom Lane2011-01-25
| | | | | | | | | | | | | | | | | | | This feature allows a unique or pkey constraint to be created using an already-existing unique index. While the constraint isn't very functionally different from the bare index, it's nice to be able to do that for documentation purposes. The main advantage over just issuing a plain ALTER TABLE ADD UNIQUE/PRIMARY KEY is that the index can be created with CREATE INDEX CONCURRENTLY, so that there is not a long interval where the table is locked against updates. On the way, refactor some of the code in DefineIndex() and index_create() so that we don't have to pass through those functions in order to create the index constraint's catalog entries. Also, in parse_utilcmd.c, pass around the ParseState pointer in struct CreateStmtContext to save on notation, and add error location pointers to some error reports that didn't have one before. Gurjeet Singh, reviewed by Steve Singer and Tom Lane
* Fix PlanRowMark/ExecRowMark structures to handle inheritance correctly.Tom Lane2011-01-12
| | | | | | | | | | | | | | | | | | In an inherited UPDATE/DELETE, each target table has its own subplan, because it might have a column set different from other targets. This means that the resjunk columns we add to support EvalPlanQual might be at different physical column numbers in each subplan. The EvalPlanQual rewrite I did for 9.0 failed to account for this, resulting in possible misbehavior or even crashes during concurrent updates to the same row, as seen in a recent report from Gordon Shannon. Revise the data structure so that we track resjunk column numbers separately for each subplan. I also chose to move responsibility for identifying the physical column numbers back to executor startup, instead of assuming that numbers derived during preprocess_targetlist would stay valid throughout subsequent massaging of the plan. That's a bit slower, so we might want to consider undoing it someday; but it would complicate the patch considerably and didn't seem justifiable in a bug fix that has to be back-patched to 9.0.
* Basic foreign table support.Robert Haas2011-01-01
| | | | | | | | | | | Foreign tables are a core component of SQL/MED. This commit does not provide a working SQL/MED infrastructure, because foreign tables cannot yet be queried. Support for foreign table scans will need to be added in a future patch. However, this patch creates the necessary system catalog structure, syntax support, and support for ancillary operations such as COMMENT and SECURITY LABEL. Shigeru Hanada, heavily revised by Robert Haas
* Stamp copyrights for year 2011.Bruce Momjian2011-01-01
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* Generalize concept of temporary relations to "relation persistence".Robert Haas2010-12-13
| | | | | | | | | | | | | | | This commit replaces pg_class.relistemp with pg_class.relpersistence; and also modifies the RangeVar node type to carry relpersistence rather than istemp. It also removes removes rd_istemp from RelationData and instead performs the correct computation based on relpersistence. For clarity, we add three new macros: RelationNeedsWAL(), RelationUsesLocalBuffers(), and RelationUsesTempNamespace(), so that we can clarify the purpose of each check that previous depended on rd_istemp. This is intended as infrastructure for the upcoming unlogged tables patch, as well as for future possible work on global temporary tables.
* Add a stack overflow check to copyObject().Tom Lane2010-12-06
| | | | | | | | | | | | | | | There are some code paths, such as SPI_execute(), where we invoke copyObject() on raw parse trees before doing parse analysis on them. Since the bison grammar is capable of building heavily nested parsetrees while itself using only minimal stack depth, this means that copyObject() can be the front-line function that hits stack overflow before anything else does. Accordingly, it had better have a check_stack_depth() call. I did a bit of performance testing and found that this slows down copyObject() by only a few percent, so the hit ought to be negligible in the context of complete processing of a query. Per off-list report from Toshihide Katayama. Back-patch to all supported branches.
* Create core infrastructure for KNNGIST.Tom Lane2010-12-02
| | | | | | | | | | | | | | | | | | | This is a heavily revised version of builtin_knngist_core-0.9. The ordering operators are no longer mixed in with actual quals, which would have confused not only humans but significant parts of the planner. Instead, ordering operators are carried separately throughout planning and execution. Since the API for ambeginscan and amrescan functions had to be changed anyway, this commit takes the opportunity to rationalize that a bit. RelationGetIndexScan no longer forces a premature index_rescan call; instead, callers of index_beginscan must call index_rescan too. Aside from making the AM-side initialization logic a bit less peculiar, this has the advantage that we do not make a useless extra am_rescan call when there are runtime key values. AMs formerly could not assume that the key values passed to amrescan were actually valid; now they can. Teodor Sigaev and Tom Lane
* Create the system catalog infrastructure needed for KNNGIST.Tom Lane2010-11-24
| | | | | | | | | | | | | | | | This commit adds columns amoppurpose and amopsortfamily to pg_amop, and column amcanorderbyop to pg_am. For the moment all the entries in amcanorderbyop are "false", since the underlying support isn't there yet. Also, extend the CREATE OPERATOR CLASS/ALTER OPERATOR FAMILY commands with [ FOR SEARCH | FOR ORDER BY sort_operator_family ] clauses to allow the new columns of pg_amop to be populated, and create pg_dump support for dumping that information. I also added some documentation, although it's perhaps a bit premature given that the feature doesn't do anything useful yet. Teodor Sigaev, Robert Haas, Tom Lane
* Propagate ALTER TYPE operations to typed tablesPeter Eisentraut2010-11-23
| | | | | This adds RESTRICT/CASCADE flags to ALTER TYPE ... ADD/DROP/ALTER/ RENAME ATTRIBUTE to control whether to alter typed tables as well.
* Reimplement planner's handling of MIN/MAX aggregate optimization.Tom Lane2010-11-04
| | | | | | | | | | | | | | | | | | | | | | Per my recent proposal, get rid of all the direct inspection of indexes and manual generation of paths in planagg.c. Instead, set up EquivalenceClasses for the aggregate argument expressions, and let the regular path generation logic deal with creating paths that can satisfy those sort orders. This makes planagg.c a bit more visible to the rest of the planner than it was originally, but the approach is basically a lot cleaner than before. A major advantage of doing it this way is that we get MIN/MAX optimization on inheritance trees (using MergeAppend of indexscans) practically for free, whereas in the old way we'd have had to add a whole lot more duplicative logic. One small disadvantage of this approach is that MIN/MAX aggregates can no longer exploit partial indexes having an "x IS NOT NULL" predicate, unless that restriction or something that implies it is specified in the query. The previous implementation was able to use the added "x IS NOT NULL" condition as an extra predicate proof condition, but in this version we rely entirely on indexes that are considered usable by the main planning process. That seems a fair tradeoff for the simplicity and functionality gained.
* Provide hashing support for arrays.Tom Lane2010-10-30
| | | | | | | | | | | | | | | | | | | | | The core of this patch is hash_array() and associated typcache infrastructure, which works just about exactly like the existing support for array comparison. In addition I did some work to ensure that the planner won't think that an array type is hashable unless its element type is hashable, and similarly for sorting. This includes adding a datatype parameter to op_hashjoinable and op_mergejoinable, and adding an explicit "hashable" flag to SortGroupClause. The lack of a cross-check on the element type was a pre-existing bug in mergejoin support --- but it didn't matter so much before, because if you couldn't sort the element type there wasn't any good alternative to failing anyhow. Now that we have the alternative of hashing the array type, there are cases where we can avoid a failure by being picky at the planner stage, so it's time to be picky. The issue of exactly how to combine the per-element hash values to produce an array hash is still open for discussion, but the rest of this is pretty solid, so I'll commit it as-is.
* Allow new values to be added to an existing enum type.Tom Lane2010-10-24
| | | | | | | After much expenditure of effort, we've got this to the point where the performance penalty is pretty minimal in typical cases. Andrew Dunstan, reviewed by Brendan Jurd, Dean Rasheed, and Tom Lane
* Allow WITH clauses to be attached to INSERT, UPDATE, DELETE statements.Tom Lane2010-10-15
| | | | | | | | | | | | | | | | This is not the hoped-for facility of using INSERT/UPDATE/DELETE inside a WITH, but rather the other way around. It seems useful in its own right anyway. Note: catversion bumped because, although the contents of stored rules might look compatible, there's actually a subtle semantic change. A single Query containing a WITH and INSERT...VALUES now represents writing the WITH before the INSERT, not before the VALUES. While it's not clear that that matters to anyone, it seems like a good idea to have it cited in the git history for catversion.h. Original patch by Marko Tiikkaja, with updating and cleanup by Hitoshi Harada.
* Support MergeAppend plans, to allow sorted output from append relations.Tom Lane2010-10-14
| | | | | | | | | This patch eliminates the former need to sort the output of an Append scan when an ordered scan of an inheritance tree is wanted. This should be particularly useful for fast-start cases such as queries with LIMIT. Original patch by Greg Stark, with further hacking by Hans-Jurgen Schonig, Robert Haas, and Tom Lane.
* Support triggers on views.Tom Lane2010-10-10
| | | | | | | | | | | | | | | This patch adds the SQL-standard concept of an INSTEAD OF trigger, which is fired instead of performing a physical insert/update/delete. The trigger function is passed the entire old and/or new rows of the view, and must figure out what to do to the underlying tables to implement the update. So this feature can be used to implement updatable views using trigger programming style rather than rule hacking. In passing, this patch corrects the names of some columns in the information_schema.triggers view. It seems the SQL committee renamed them somewhere between SQL:99 and SQL:2003. Dean Rasheed, reviewed by Bernd Helmle; some additional hacking by me.
* Fix PlaceHolderVar mechanism's interaction with outer joins.Tom Lane2010-09-28
| | | | | | | | | | | | | | The point of a PlaceHolderVar is to allow a non-strict expression to be evaluated below an outer join, after which its value bubbles up like a Var and can be forced to NULL when the outer join's semantics require that. However, there was a serious design oversight in that, namely that we didn't ensure that there was actually a correct place in the plan tree to evaluate the placeholder :-(. It may be necessary to delay evaluation of an outer join to ensure that a placeholder that should be evaluated below the join can be evaluated there. Per recent bug report from Kirill Simonov. Back-patch to 8.4 where the PlaceHolderVar mechanism was introduced.
* Add a SECURITY LABEL command.Robert Haas2010-09-27
| | | | | | | | This is intended as infrastructure to support integration with label-based mandatory access control systems such as SE-Linux. Further changes (mostly hooks) will be needed, but this is a big chunk of it. KaiGai Kohei and Robert Haas
* Remove cvs keywords from all files.Magnus Hagander2010-09-20
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* Fix failure of "ALTER TABLE t ADD COLUMN c serial" when done by non-owner.Tom Lane2010-08-18
| | | | | | | | | | | | | | | | | The implicitly created sequence was created as owned by the current user, who could be different from the table owner, eg if current user is a superuser or some member of the table's owning role. This caused sanity checks in the SEQUENCE OWNED BY code to spit up. Although possibly we don't need those sanity checks, the safest fix seems to be to make sure the implicit sequence is assigned the same owner role as the table has. (We still do all permissions checks as the current user, however.) Per report from Josh Berkus. Back-patch to 9.0. The bug goes back to the invention of SEQUENCE OWNED BY in 8.2, but the fix requires an API change for DefineRelation(), which seems to have potential for breaking third-party code if done in a minor release. Given the lack of prior complaints, it's probably not worth fixing in the stable branches.
* Add missing handling of PlannedStmt.transientPlan in copyfuncs/outfuncs.Tom Lane2010-08-18
| | | | | | | | | | | | _outPlannedStmt is only debug support, so the omission there was not very serious, but the omission in _copyPlannedStmt is a real bug. The consequence would be that a copied plan tree would never be marked as a transient plan, so that we would forget we ought to replan it after some not-yet-ready index becomes ready for use. This might explain some past complaints about indexes created with CREATE INDEX CONCURRENTLY not being used right away. Problem spotted by Yeb Havinga. Back-patch to 8.3, where the field was added.
* Recognize functional dependency on primary keys. This allows a table'sTom Lane2010-08-07
| | | | | | | | | | | | | other columns to be referenced without listing them in GROUP BY, so long as the primary key column(s) are listed in GROUP BY. Eventually we should also allow functional dependency on a UNIQUE constraint when the columns are marked NOT NULL, but that has to wait until NOT NULL constraints are represented in pg_constraint, because we need to have pg_constraint OIDs for all the conditions needed to ensure functional dependency. Peter Eisentraut, reviewed by Alex Hunsaker and Tom Lane
* CREATE TABLE IF NOT EXISTS.Robert Haas2010-07-25
| | | | Reviewed by Bernd Helmle.
* Make NestLoop plan nodes pass outer-relation variables into their innerTom Lane2010-07-12
| | | | | | | | | | | | relation using the general PARAM_EXEC executor parameter mechanism, rather than the ad-hoc kluge of passing the outer tuple down through ExecReScan. The previous method was hard to understand and could never be extended to handle parameters coming from multiple join levels. This patch doesn't change the set of possible plans nor have any significant performance effect, but it's necessary infrastructure for future generalization of the concept of an inner indexscan plan. ExecReScan's second parameter is now unused, so it's removed.
* pgindent run for 9.0Bruce Momjian2010-02-26
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* Add an OR REPLACE option to CREATE LANGUAGE.Tom Lane2010-02-23
| | | | | | | | | | | | | | | This operates in the same way as other CREATE OR REPLACE commands, ie, it replaces everything but the ownership and ACL lists of an existing entry, and requires the caller to have owner privileges for that entry. While modifying an existing language has some use in development scenarios, in typical usage all the "replaced" values come from pg_pltemplate so there will be no actual change in the language definition. The reason for adding this is mainly to allow programs to ensure that a language exists without triggering an error if it already does exist. This commit just adds and documents the new option. A followon patch will use it to clean up some unpleasant cases in pg_dump and pg_regress.
* Replace the pg_listener-based LISTEN/NOTIFY mechanism with an in-memory queue.Tom Lane2010-02-16
| | | | | | | | | | | | In addition, add support for a "payload" string to be passed along with each notify event. This implementation should be significantly more efficient than the old one, and is also more compatible with Hot Standby usage. There is not yet any facility for HS slaves to receive notifications generated on the master, although such a thing is possible in future. Joachim Wieland, reviewed by Jeff Davis; also hacked on by me.
* Extend the set of frame options supported for window functions.Tom Lane2010-02-12
| | | | | | | | | This patch allows the frame to start from CURRENT ROW (in either RANGE or ROWS mode), and it also adds support for ROWS n PRECEDING and ROWS n FOLLOWING start and end points. (RANGE value PRECEDING/FOLLOWING isn't there yet --- the grammar works, but that's all.) Hitoshi Harada, reviewed by Pavel Stehule
* Type table featurePeter Eisentraut2010-01-28
| | | | This adds the CREATE TABLE name OF type command, per SQL standard.
* Support ALTER TABLESPACE name SET/RESET ( tablespace_options ).Robert Haas2010-01-05
| | | | | | | | | This patch only supports seq_page_cost and random_page_cost as parameters, but it provides the infrastructure to scalably support many more. In particular, we may want to add support for effective_io_concurrency, but I'm leaving that as future work for now. Thanks to Tom Lane for design help and Alvaro Herrera for the review.
* Update copyright for the year 2010.Bruce Momjian2010-01-02
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* Add an "argisrow" field to NullTest nodes, following a plan made way back inTom Lane2010-01-01
| | | | | | 8.2beta but never carried out. This avoids repetitive tests of whether the argument is of scalar or composite type. Also, be a bit more paranoid about composite arguments in some places where we previously weren't checking.
* Add the ability to store inheritance-tree statistics in pg_statistic,Tom Lane2009-12-29
| | | | | | | | and teach ANALYZE to compute such stats for tables that have subclasses. Per my proposal of yesterday. autovacuum still needs to be taught about running ANALYZE on parent tables when their subclasses change, but the feature is useful even without that.
* Adjust naming of indexes and their columns per recent discussion.Tom Lane2009-12-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Index expression columns are now named after the FigureColname result for their expressions, rather than always being "pg_expression_N". Digits are appended to this name if needed to make the column name unique within the index. (That happens for regular columns too, thus fixing the old problem that CREATE INDEX fooi ON foo (f1, f1) fails. Before exclusion indexes there was no real reason to do such a thing, but now maybe there is.) Default names for indexes and associated constraints now include the column names of all their columns, not only the first one as in previous practice. (Of course, this will be truncated as needed to fit in NAMEDATALEN. Also, pkey indexes retain the historical behavior of not naming specific columns at all.) An example of the results: regression=# create table foo (f1 int, f2 text, regression(# exclude (f1 with =, lower(f2) with =)); NOTICE: CREATE TABLE / EXCLUDE will create implicit index "foo_f1_lower_exclusion" for table "foo" CREATE TABLE regression=# \d foo_f1_lower_exclusion Index "public.foo_f1_lower_exclusion" Column | Type | Definition --------+---------+------------ f1 | integer | f1 lower | text | lower(f2) btree, for table "public.foo"
* Support ORDER BY within aggregate function calls, at long last providing aTom Lane2009-12-15
| | | | | | | | | | | | | non-kluge method for controlling the order in which values are fed to an aggregate function. At the same time eliminate the old implementation restriction that DISTINCT was only supported for single-argument aggregates. Possibly release-notable behavioral change: formerly, agg(DISTINCT x) dropped null values of x unconditionally. Now, it does so only if the agg transition function is strict; otherwise nulls are treated as DISTINCT normally would, ie, you get one copy. Andrew Gierth, reviewed by Hitoshi Harada
* Add exclusion constraints, which generalize the concept of uniqueness toTom Lane2009-12-07
| | | | | | | | support any indexable commutative operator, not just equality. Two rows violate the exclusion constraint if "row1.col OP row2.col" is TRUE for each of the columns in the constraint. Jeff Davis, reviewed by Robert Haas
* Add a WHEN clause to CREATE TRIGGER, allowing a boolean expression to beTom Lane2009-11-20
| | | | | | | | | | | checked to determine whether the trigger should be fired. For BEFORE triggers this is mostly a matter of spec compliance; but for AFTER triggers it can provide a noticeable performance improvement, since queuing of a deferred trigger event and re-fetching of the row(s) at end of statement can be short-circuited if the trigger does not need to be fired. Takahiro Itagaki, reviewed by KaiGai Kohei.
* Provide a parenthesized-options syntax for VACUUM, analogous to that recentlyTom Lane2009-11-16
| | | | | | | | adopted for EXPLAIN. This will allow additional options to be implemented in future without having to make them fully-reserved keywords. The old syntax remains available for existing options, however. Itagaki Takahiro
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