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* Simplify handling of remote-qual pass-forward in postgres_fdw.Tom Lane2017-04-11
| | | | | | | | | | | | | | | | | | | | | | Commit 0bf3ae88a encountered a need to pass the finally chosen remote qual conditions forward from postgresGetForeignPlan to postgresPlanDirectModify. It solved that by sticking them into the plan node's fdw_private list, which in hindsight was a pretty bad idea. In the first place, there's no use for those qual trees either in EXPLAIN or execution; indeed they could never safely be used for any post-planning purposes, because they would not get processed by setrefs.c. So they're just dead weight to carry around in the finished plan tree, plus being an attractive nuisance for somebody who might get the idea that they could be used that way. Secondly, because those qual trees (sometimes) contained RestrictInfos, they created a plan-transmission hazard for parallel query, which is how come we noticed a problem. We dealt with that symptom in commit 28b047875, but really a more straightforward and more efficient fix is to pass the data through in a new field of struct PgFdwRelationInfo. So do it that way. (There's no need to revert 28b047875, as it has sufficient reason to live anyway.) Per fuzz testing by Andreas Seltenreich. Discussion: https://postgr.es/m/87tw5x4vcu.fsf@credativ.de
* Handle restriction clause lists more uniformly in postgres_fdw.Tom Lane2017-04-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Clauses in the lists retained by postgres_fdw during planning were sometimes bare boolean clauses, sometimes RestrictInfos, and sometimes a mixture of the two in the same list. The comment about that situation didn't come close to telling the full truth, either. Aside from being confusing, this had a couple of bad practical consequences: * waste of planning cycles due to inability to cache per-clause selectivity and cost estimates; * sometimes, RestrictInfos would sneak into the fdw_private list of a finished Plan node, causing failures if, for example, we tried to ship the Plan tree to a parallel worker. (It may well be that it's a bug in the parallel-query logic that we would ever try to ship such a plan to a parallel worker, but in any case this deserves to be cleaned up.) To fix, rearrange so that clause lists in PgFdwRelationInfo are always lists of RestrictInfos, and then strip the RestrictInfos at the last minute when making a Plan node. In passing do a bit of refactoring and comment cleanup in postgresGetForeignPlan and foreign_join_ok. Although the messiness here dates back at least to 9.6, there's no evidence that it causes anything worse than wasted planning cycles in 9.6, so no back-patch for now. Per fuzz testing by Andreas Seltenreich. Tom Lane and Ashutosh Bapat Discussion: https://postgr.es/m/87tw5x4vcu.fsf@credativ.de
* 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
* Optimize joins when the inner relation can be proven unique.Tom Lane2017-04-07
| | | | | | | | | | | | | | | | | | | | | | | If there can certainly be no more than one matching inner row for a given outer row, then the executor can move on to the next outer row as soon as it's found one match; there's no need to continue scanning the inner relation for this outer row. This saves useless scanning in nestloop and hash joins. In merge joins, it offers the opportunity to skip mark/restore processing, because we know we have not advanced past the first possible match for the next outer row. Of course, the devil is in the details: the proof of uniqueness must depend only on joinquals (not otherquals), and if we want to skip mergejoin mark/restore then it must depend only on merge clauses. To avoid adding more planning overhead than absolutely necessary, the present patch errs in the conservative direction: there are cases where inner_unique or skip_mark_restore processing could be used, but it will not do so because it's not sure that the uniqueness proof depended only on "safe" clauses. This could be improved later. David Rowley, reviewed and rather heavily editorialized on by me Discussion: https://postgr.es/m/CAApHDvqF6Sw-TK98bW48TdtFJ+3a7D2mFyZ7++=D-RyPsL76gw@mail.gmail.com
* Reset API of clause_selectivity()Simon Riggs2017-04-06
| | | | Discussion: https://postgr.es/m/CAKJS1f9yurJQW9pdnzL+rmOtsp2vOytkpXKGnMFJEO-qz5O5eA@mail.gmail.com
* Collect and use multi-column dependency statsSimon Riggs2017-04-05
| | | | | | | | | | | | | | | | | | Follow on patch in the multi-variate statistics patch series. CREATE STATISTICS s1 WITH (dependencies) ON (a, b) FROM t; ANALYZE; will collect dependency stats on (a, b) and then use the measured dependency in subsequent query planning. Commit 7b504eb282ca2f5104b5c00b4f05a3ef6bb1385b added CREATE STATISTICS with n-distinct coefficients. These are now specified using the mutually exclusive option WITH (ndistinct). Author: Tomas Vondra, David Rowley Reviewed-by: Kyotaro HORIGUCHI, Álvaro Herrera, Dean Rasheed, Robert Haas and many other comments and contributions Discussion: https://postgr.es/m/56f40b20-c464-fad2-ff39-06b668fac47c@2ndquadrant.com
* Capitalize names of PLs consistentlyPeter Eisentraut2017-04-05
| | | | Author: Daniel Gustafsson <daniel@yesql.se>
* Abstract logic to allow for multiple kinds of child rels.Robert Haas2017-04-03
| | | | | | | | | | | | | | | | | | | | | | Currently, the only type of child relation is an "other member rel", which is the child of a baserel, but in the future joins and even upper relations may have child rels. To facilitate that, introduce macros that test to test for particular RelOptKind values, and use them in various places where they help to clarify the sense of a test. (For example, a test may allow RELOPT_OTHER_MEMBER_REL either because it intends to allow child rels, or because it intends to allow simple rels.) Also, remove find_childrel_top_parent, which will not work for a child rel that is not a baserel. Instead, add a new RelOptInfo member top_parent_relids to track the same kind of information in a more generic manner. Ashutosh Bapat, slightly tweaked by me. Review and testing of the patch set from which this was taken by Rajkumar Raghuwanshi and Rafia Sabih. Discussion: http://postgr.es/m/CA+TgmoagTnF2yqR3PT2rv=om=wJiZ4-A+ATwdnriTGku1CLYxA@mail.gmail.com
* postgres_fdw: Teach IMPORT FOREIGN SCHEMA about partitioning.Robert Haas2017-03-31
| | | | | | | | | | Don't import partitions. Do import partitioned tables which are not themselves partitions. Report by Stephen Frost. Design and patch by Michael Paquier, reviewed by Amit Langote. Documentation revised by me. Discussion: http://postgr.es/m/20170309141531.GD9812@tamriel.snowman.net
* Support hashed aggregation with grouping sets.Andrew Gierth2017-03-27
| | | | | | | | | | | | | | | | | | This extends the Aggregate node with two new features: HashAggregate can now run multiple hashtables concurrently, and a new strategy MixedAggregate populates hashtables while doing sorted grouping. The planner will now attempt to save as many sorts as possible when planning grouping sets queries, while not exceeding work_mem for the estimated combined sizes of all hashtables used. No SQL-level changes are required. There should be no user-visible impact other than the new EXPLAIN output and possible changes to result ordering when ORDER BY was not used (which affected a few regression tests). The enable_hashagg option is respected. Author: Andrew Gierth Reviewers: Mark Dilger, Andres Freund Discussion: https://postgr.es/m/87vatszyhj.fsf@news-spur.riddles.org.uk
* Faster expression evaluation and targetlist projection.Andres Freund2017-03-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This replaces the old, recursive tree-walk based evaluation, with non-recursive, opcode dispatch based, expression evaluation. Projection is now implemented as part of expression evaluation. This both leads to significant performance improvements, and makes future just-in-time compilation of expressions easier. The speed gains primarily come from: - non-recursive implementation reduces stack usage / overhead - simple sub-expressions are implemented with a single jump, without function calls - sharing some state between different sub-expressions - reduced amount of indirect/hard to predict memory accesses by laying out operation metadata sequentially; including the avoidance of nearly all of the previously used linked lists - more code has been moved to expression initialization, avoiding constant re-checks at evaluation time Future just-in-time compilation (JIT) has become easier, as demonstrated by released patches intended to be merged in a later release, for primarily two reasons: Firstly, due to a stricter split between expression initialization and evaluation, less code has to be handled by the JIT. Secondly, due to the non-recursive nature of the generated "instructions", less performance-critical code-paths can easily be shared between interpreted and compiled evaluation. The new framework allows for significant future optimizations. E.g.: - basic infrastructure for to later reduce the per executor-startup overhead of expression evaluation, by caching state in prepared statements. That'd be helpful in OLTPish scenarios where initialization overhead is measurable. - optimizing the generated "code". A number of proposals for potential work has already been made. - optimizing the interpreter. Similarly a number of proposals have been made here too. The move of logic into the expression initialization step leads to some backward-incompatible changes: - Function permission checks are now done during expression initialization, whereas previously they were done during execution. In edge cases this can lead to errors being raised that previously wouldn't have been, e.g. a NULL array being coerced to a different array type previously didn't perform checks. - The set of domain constraints to be checked, is now evaluated once during expression initialization, previously it was re-built every time a domain check was evaluated. For normal queries this doesn't change much, but e.g. for plpgsql functions, which caches ExprStates, the old set could stick around longer. The behavior around might still change. Author: Andres Freund, with significant changes by Tom Lane, changes by Heikki Linnakangas Reviewed-By: Tom Lane, Heikki Linnakangas Discussion: https://postgr.es/m/20161206034955.bh33paeralxbtluv@alap3.anarazel.de
* postgres_fdw: Push down FULL JOINs with restriction clauses.Robert Haas2017-03-16
| | | | | | | | | | | The previous deparsing logic wasn't smart enough to produce subqueries when deparsing; make it smart enough to do that. However, we only do it that way when necessary, because it generates more complicated SQL which will be harder for any humans reading the queries to understand. Etsuro Fujita, reviewed by Ashutosh Bapat Discussion: http://postgr.es/m/c449261a-b033-dc02-9254-2fe5b7044795@lab.ntt.co.jp
* Fix hard-coded relkind constants in assorted other files.Tom Lane2017-03-09
| | | | | | | | | | | | Although it's reasonable to expect that most of these constants will never change, that does not make it good programming style to hard-code the value rather than using the RELKIND_FOO macros. I think I've now gotten all the hard-coded references in C code. Unfortunately there's no equally convenient way to parameterize SQL files ... Discussion: https://postgr.es/m/11145.1488931324@sss.pgh.pa.us
* chomp PQerrorMessage() in backend usesPeter Eisentraut2017-02-27
| | | | | | | | PQerrorMessage() returns an error message with a trailing newline, but in backend use (dblink, postgres_fdw, libpqwalreceiver), we want to have the error message without that for emitting via ereport(). To simplify that, add a function pchomp() that returns a pstrdup'ed string with the trailing newline characters removed.
* Fix typos in comments.Heikki Linnakangas2017-02-06
| | | | | | | | | Backpatch to all supported versions, where applicable, to make backpatching of future fixes go more smoothly. Josh Soref Discussion: https://www.postgresql.org/message-id/CACZqfqCf+5qRztLPgmmosr-B0Ye4srWzzw_mo4c_8_B_mtjmJQ@mail.gmail.com
* Fix typo in comment.Robert Haas2017-01-27
| | | | Etsuro Fujita
* Use the new castNode() macro in a number of places.Andres Freund2017-01-26
| | | | | | | | | This is far from a pervasive conversion, but it's a good starting point. Author: Peter Eisentraut, with some minor changes by me Reviewed-By: Tom Lane Discussion: https://postgr.es/m/c5d387d9-3440-f5e0-f9d4-71d53b9fbe52@2ndquadrant.com
* Improve speed of contrib/postgres_fdw regression tests.Tom Lane2017-01-25
| | | | | | | | | | | Commit 7012b132d added some tests that consumed an excessive amount of time, more than tripling the time needed for "make installcheck" for this module. Add filter conditions to reduce the number of rows scanned, bringing the runtime down to within hailing distance of what it was before. Jeevan Chalke and Ashutosh Bapat, per a gripe from me Discussion: https://postgr.es/m/16565.1478104765@sss.pgh.pa.us
* Move some things from builtins.h to new header filesPeter Eisentraut2017-01-20
| | | | This avoids that builtins.h has to include additional header files.
* Remove obsoleted code relating to targetlist SRF evaluation.Andres Freund2017-01-19
| | | | | | | | | | | | | Since 69f4b9c plain expression evaluation (and thus normal projection) can't return sets of tuples anymore. Thus remove code dealing with that possibility. This will require adjustments in external code using ExecEvalExpr()/ExecProject() - that should neither be hard nor very common. Author: Andres Freund and Tom Lane Discussion: https://postgr.es/m/20160822214023.aaxz5l4igypowyri@alap3.anarazel.de
* Invalidate cached plans on FDW option changes.Tom Lane2017-01-06
| | | | | | | | | | | | | | | | | | | | | | | | This fixes problems where a plan must change but fails to do so, as seen in a bug report from Rajkumar Raghuwanshi. For ALTER FOREIGN TABLE OPTIONS, do this through the standard method of forcing a relcache flush on the table. For ALTER FOREIGN DATA WRAPPER and ALTER SERVER, just flush the whole plan cache on any change in pg_foreign_data_wrapper or pg_foreign_server. That matches the way we handle some other low-probability cases such as opclass changes, and it's unclear that the case arises often enough to be worth working harder. Besides, that gives a patch that is simple enough to back-patch with confidence. Back-patch to 9.3. In principle we could apply the code change to 9.2 as well, but (a) we lack postgres_fdw to test it with, (b) it's doubtful that anyone is doing anything exciting enough with FDWs that far back to need this desperately, and (c) the patch doesn't apply cleanly. Patch originally by Amit Langote, reviewed by Etsuro Fujita and Ashutosh Bapat, who each contributed substantial changes as well. Discussion: https://postgr.es/m/CAKcux6m5cA6rRPTKkqVdJ-R=KKDfe35Q_ZuUqxDSV_4hwga=og@mail.gmail.com
* Update copyright via script for 2017Bruce Momjian2017-01-03
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* Improve dblink error message when remote does not provide itJoe Conway2016-12-21
| | | | | | | | | | | | | When dblink or postgres_fdw detects an error on the remote side of the connection, it will try to construct a local error message as best it can using libpq's PQresultErrorField(). When no primary message is available, it was bailing out with an unhelpful "unknown error". Make that message better and more style guide compliant. Per discussion on hackers. Backpatch to 9.2 except postgres_fdw which didn't exist before 9.3. Discussion: https://postgr.es/m/19872.1482338965%40sss.pgh.pa.us
* postgres_fdw: Fix typo in comment.Robert Haas2016-11-04
| | | | Etsuro Fujita
* psql: Split up "Modifiers" column in \d and \dDPeter Eisentraut2016-11-03
| | | | | | Make separate columns "Collation", "Nullable", "Default". Reviewed-by: Kuntal Ghosh <kuntalghosh.2007@gmail.com>
* Use NIL instead of NULL for an empty List.Robert Haas2016-11-03
| | | | Tatsuro Yamada, reviewed by Ashutosh Bapat
* Don't convert Consts into Vars during setrefs.c processing.Tom Lane2016-11-02
| | | | | | | | | | | | | | | | | | | | | | | | | While converting expressions in an upper-level plan node so that they reference Vars and expressions provided by the input plan node(s), don't convert plain Const items, even if there happens to be a matching Const in the input. It's silly to do so because a Var is more expensive to execute than a Const. Moreover, converting can fool ExecCheckPlanOutput's check that an insert or update query inserts nulls into dropped columns, leading to "query provides a value for a dropped column" errors during INSERT or UPDATE on a table with a dropped column. We could solve this by making that check more complicated, but I don't see the point; this fix should save a marginal number of cycles, and it also makes for less messy EXPLAIN output, as shown by the ensuing regression test result changes. Per report from Pavel Hanák. I have not incorporated a test case based on that example, as there doesn't seem to be a simple way of checking this in isolation without making a bunch of assumptions about other planner and SQL-function behavior. Back-patch to 9.6. This setrefs.c behavior exists much further back, but there is not currently reason to think that it causes problems before 9.6. Discussion: <83shraampf.fsf@is-it.eu>
* postgres_fdw: Fix typo in comment.Robert Haas2016-11-01
| | | | Etsuro Fujita
* Suppress unused-variable warning in non-assert builds.Tom Lane2016-10-26
| | | | | | Introduced in commit 7012b132d. Kyotaro Horiguchi
* postgres_fdw: Try again to stabilize aggregate pushdown regression tests.Robert Haas2016-10-24
| | | | | | | | A query that only aggregates one row isn't a great argument for pushdown, and buildfarm member brolga decides against it. Adjust the query a bit in the hopes of getting remote aggregation to win consistently. Jeevan Chalke, per suggestion from Tom Lane
* postgres_fdw: Attempt to stabilize regression results.Robert Haas2016-10-21
| | | | | | | | | | | Set enable_hashagg to false for tests involving least_agg(), so that we get the same plan regardless of local costing variances. Also, remove a test involving sqrt(); it's there to test deparsing of HAVING clauses containing expressions, but that's tested elsewhere anyway, and sqrt(2) deparses with different amounts of precision on different machines. Per buildfarm.
* postgres_fdw: Push down aggregates to remote servers.Robert Haas2016-10-21
| | | | | | | | | | | | | Now that the upper planner uses paths, and now that we have proper hooks to inject paths into the upper planning process, it's possible for foreign data wrappers to arrange to push aggregates to the remote side instead of fetching all of the rows and aggregating them locally. This figures to be a massive win for performance, so teach postgres_fdw to do it. Jeevan Chalke and Ashutosh Bapat. Reviewed by Ashutosh Bapat with additional testing by Prabhat Sahu. Various mostly cosmetic changes by me.
* Rename WAIT_* constants to PG_WAIT_*.Robert Haas2016-10-05
| | | | | | | | Windows apparently has a constant named WAIT_TIMEOUT, and some of these other names are pretty generic, too. Insert "PG_" at the front of each name in order to disambiguate. Michael Paquier
* Extend framework from commit 53be0b1ad to report latch waits.Robert Haas2016-10-04
| | | | | | | | | | | | | | | | | | | | | | WaitLatch, WaitLatchOrSocket, and WaitEventSetWait now taken an additional wait_event_info parameter; legal values are defined in pgstat.h. This makes it possible to uniquely identify every point in the core code where we are waiting for a latch; extensions can pass WAIT_EXTENSION. Because latches were the major wait primitive not previously covered by this patch, it is now possible to see information in pg_stat_activity on a large number of important wait events not previously addressed, such as ClientRead, ClientWrite, and SyncRep. Unfortunately, many of the wait events added by this patch will fail to appear in pg_stat_activity because they're only used in background processes which don't currently appear in pg_stat_activity. We should fix this either by creating a separate view for such information, or else by deciding to include them in pg_stat_activity after all. Michael Paquier and Robert Haas, reviewed by Alexander Korotkov and Thomas Munro.
* Add macros to make AllocSetContextCreate() calls simpler and safer.Tom Lane2016-08-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I found that half a dozen (nearly 5%) of our AllocSetContextCreate calls had typos in the context-sizing parameters. While none of these led to especially significant problems, they did create minor inefficiencies, and it's now clear that expecting people to copy-and-paste those calls accurately is not a great idea. Let's reduce the risk of future errors by introducing single macros that encapsulate the common use-cases. Three such macros are enough to cover all but two special-purpose contexts; those two calls can be left as-is, I think. While this patch doesn't in itself improve matters for third-party extensions, it doesn't break anything for them either, and they can gradually adopt the simplified notation over time. In passing, change TopMemoryContext to use the default allocation parameters. Formerly it could only be extended 8K at a time. That was probably reasonable when this code was written; but nowadays we create many more contexts than we did then, so that it's not unusual to have a couple hundred K in TopMemoryContext, even without considering various dubious code that sticks other things there. There seems no good reason not to let it use growing blocks like most other contexts. Back-patch to 9.6, mostly because that's still close enough to HEAD that it's easy to do so, and keeping the branches in sync can be expected to avoid some future back-patching pain. The bugs fixed by these changes don't seem to be significant enough to justify fixing them further back. Discussion: <21072.1472321324@sss.pgh.pa.us>
* Support OID system column in postgres_fdw.Heikki Linnakangas2016-08-26
| | | | | | | | | | You can use ALTER FOREIGN TABLE SET WITH OIDS on a foreign table, but the oid column read out as zeros, because the postgres_fdw didn't know about it. Teach postgres_fdw how to fetch it. Etsuro Fujita, with an additional test case by me. Discussion: <56E90A76.5000503@lab.ntt.co.jp>
* postgres_fdw: Cosmetic cleanup.Robert Haas2016-08-24
| | | | Etsuro Fujita
* Fix assorted fallout from IS [NOT] NULL patch.Tom Lane2016-07-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commits 4452000f3 et al established semantics for NullTest.argisrow that are a bit different from its initial conception: rather than being merely a cache of whether we've determined the input to have composite type, the flag now has the further meaning that we should apply field-by-field testing as per the standard's definition of IS [NOT] NULL. If argisrow is false and yet the input has composite type, the construct instead has the semantics of IS [NOT] DISTINCT FROM NULL. Update the comments in primnodes.h to clarify this, and fix ruleutils.c and deparse.c to print such cases correctly. In the case of ruleutils.c, this merely results in cosmetic changes in EXPLAIN output, since the case can't currently arise in stored rules. However, it represents a live bug for deparse.c, which would formerly have sent a remote query that had semantics different from the local behavior. (From the user's standpoint, this means that testing a remote nested-composite column for null-ness could have had unexpected recursive behavior much like that fixed in 4452000f3.) In a related but somewhat independent fix, make plancat.c set argisrow to false in all NullTest expressions constructed to represent "attnotnull" constructs. Since attnotnull is actually enforced as a simple null-value check, this is a more accurate representation of the semantics; we were previously overpromising what it meant for composite columns, which might possibly lead to incorrect planner optimizations. (It seems that what the SQL spec expects a NOT NULL constraint to mean is an IS NOT NULL test, so arguably we are violating the spec and should fix attnotnull to do the other thing. If we ever do, this part should get reverted.) Back-patch, same as the previous commit. Discussion: <10682.1469566308@sss.pgh.pa.us>
* Fix typo in comment.Fujii Masao2016-07-25
| | | | Author: Masahiko Sawada
* Avoid invalidating all foreign-join cached plans when user mappings change.Tom Lane2016-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We must not push down a foreign join when the foreign tables involved should be accessed under different user mappings. Previously we tried to enforce that rule literally during planning, but that meant that the resulting plans were dependent on the current contents of the pg_user_mapping catalog, and we had to blow away all cached plans containing any remote join when anything at all changed in pg_user_mapping. This could have been improved somewhat, but the fact that a syscache inval callback has very limited info about what changed made it hard to do better within that design. Instead, let's change the planner to not consider user mappings per se, but to allow a foreign join if both RTEs have the same checkAsUser value. If they do, then they necessarily will use the same user mapping at runtime, and we don't need to know specifically which one that is. Post-plan-time changes in pg_user_mapping no longer require any plan invalidation. This rule does give up some optimization ability, to wit where two foreign table references come from views with different owners or one's from a view and one's directly in the query, but nonetheless the same user mapping would have applied. We'll sacrifice the first case, but to not regress more than we have to in the second case, allow a foreign join involving both zero and nonzero checkAsUser values if the nonzero one is the same as the prevailing effective userID. In that case, mark the plan as only runnable by that userID. The plancache code already had a notion of plans being userID-specific, in order to support RLS. It was a little confused though, in particular lacking clarity of thought as to whether it was the rewritten query or just the finished plan that's dependent on the userID. Rearrange that code so that it's clearer what depends on which, and so that the same logic applies to both RLS-injected role dependency and foreign-join-injected role dependency. Note that this patch doesn't remove the other issue mentioned in the original complaint, which is that while we'll reliably stop using a foreign join if it's disallowed in a new context, we might fail to start using a foreign join if it's now allowed, but we previously created a generic cached plan that didn't use one. It was agreed that the chance of winning that way was not high enough to justify the much larger number of plan invalidations that would have to occur if we tried to cause it to happen. In passing, clean up randomly-varying spelling of EXPLAIN commands in postgres_fdw.sql, and fix a COSTS ON example that had been allowed to leak into the committed tests. This reverts most of commits fbe5a3fb7 and 5d4171d1c, which were the previous attempt at ensuring we wouldn't push down foreign joins that span permissions contexts. Etsuro Fujita and Tom Lane Discussion: <d49c1e5b-f059-20f4-c132-e9752ee0113e@lab.ntt.co.jp>
* postgres_fdw: Fix cache lookup failure while creating error context.Robert Haas2016-07-01
| | | | | | | | This is fallout from join pushdown; get_relid_attribute_name can't handle an attribute number of 0, indicating a whole-row reference, and shouldn't be called in that case. Etsuro Fujita, reviewed by Ashutosh Bapat
* postgres_fdw: Remove schema-qualification from cast to text.Robert Haas2016-07-01
| | | | | | As pointed out by Ashutosh Bapat, the header comments for this file say that schema-qualification is needed for all and only those types outside pg_catalog. pg_catalog.text is not outside pg_catalog.
* postgres_fdw: Fix incorrect NULL handling in join pushdown.Robert Haas2016-06-24
| | | | | | | | | | something.* IS NOT NULL means that every attribute of the row is not NULL, not that the row itself is non-NULL (e.g. because it's coming from below an outer join. Use (somevar.*)::pg_catalog.text IS NOT NULL instead. Ashutosh Bapat, per a report by Rushabh Lathia. Reviewed by Amit Langote and Etsuro Fujita. Schema-qualification added by me.
* postgres_fdw: Remove useless return statement.Robert Haas2016-06-24
| | | | Etsuro Fujita
* postgres_fdw: Rephrase comment.Robert Haas2016-06-17
| | | | | Per gripe from Thomas Munro, who only complained about a more localized problem, but I couldn't resist a bit more wordsmithing.
* postgres_fdw: Check PlaceHolderVars before pushing down a join.Robert Haas2016-06-14
| | | | | | | | | | | | | | | | | | | As discovered by Andreas Seltenreich via sqlsmith, it's possible for a remote join to need to generate a target list which contains a PlaceHolderVar which would need to be evaluated on the remote server. This happens when we try to push down a join tree which contains outer joins and the nullable side of the join contains a subquery which evauates some expression which can go to NULL above the level of the join. Since the deparsing logic can't build a remote query that involves subqueries, it fails while trying to produce an SQL query that can be sent to the remote side. Detect such cases and don't try to push down the join at all. It's actually fine to push down the join if the PlaceHolderVar needs to be evaluated at the current join level. This patch makes a small change to build_tlist_to_deparse so that this case will work. Amit Langote, Ashutosh Bapat, and me.
* postgres_fdw: Promote an Assert() to elog().Robert Haas2016-06-14
| | | | | | | | | | Andreas Seltenreich reports that it is possible for a PlaceHolderVar to creep into this tlist, and I fear that even after that's fixed we might have other, similar bugs in this area either now or in the future. There's a lot of action-at-a-distance here, because the validity of this assertion depends on core planner behavior; so, let's use elog() to make sure we catch this even in non-assert builds, rather than just crashing.
* pgindent run for 9.6Robert Haas2016-06-09
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* postgres_fdw: Fix the fix for crash when pushing down multiple joins.Robert Haas2016-05-16
| | | | | | | | | | | | | | Commit 3151f16e1874db82ed85a005dac15368903ca9fb was intended to be a commit of a patch from Ashutosh Bapat, but instead I mistakenly committed an earlier version from Michael Paquier (because both patches were submitted with the same filename, and I confused them). Michael's patch fixes the crash but doesn't actually implement the correct test. Repair the incorrect logic, and also expand the comments considerably so that this is all more clear. Ashutosh Bapat and Robert Haas
* Fix multiple problems in postgres_fdw query cancellation logic.Robert Haas2016-05-16
| | | | | | | | | | | First, even if we cancel a query, we still have to roll back the containing transaction; otherwise, the session will be left in a failed transaction state. Second, we need to support canceling queries whe aborting a subtransaction as well as when aborting a toplevel transaction. Etsuro Fujita, reviewed by Michael Paquier