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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
* postgres_fdw: Don't push down certain full joins.Robert Haas2016-04-20
| | | | | | | | | | | | | | | | If there's a filter condition on either side of a full outer join, it is neither correct to attach it to the join's ON clause nor to throw it into the toplevel WHERE clause. Just don't push down the join in that case. To maximize the number of cases where we can still push down full joins, push inner join conditions into the ON clause at the first opportunity rather than postponing them to the top-level WHERE clause. This produces nicer SQL, anyway. This bug was introduced in e4106b2528727c4b48639c0e12bf2f70a766b910. Ashutosh Bapat, per report from Rajkumar Raghuwanshi.
* Don't require a user mapping for FDWs to work.Robert Haas2016-03-28
| | | | | | | | | Commit fbe5a3fb73102c2cfec11aaaa4a67943f4474383 accidentally changed this behavior; put things back the way they were, and add some regression tests. Report by Andres Freund; patch by Ashutosh Bapat, with a bit of kibitzing by me.
* postgres_fdw: Fix crash when pushing down multiple joins.Robert Haas2016-03-23
| | | | | | | | | A join clause might mention multiple relations on either side, so it need not be the case that a given joinrel's constituent relations are all on one side of the join clause or all on the other. Report by Rajkumar Raghuwanshi. Analysis and fix by Michael Paquier and Ashutosh Bapat.
* Directly modify foreign tables.Robert Haas2016-03-18
| | | | | | | | | postgres_fdw can now sent an UPDATE or DELETE statement directly to the foreign server in simple cases, rather than sending a SELECT FOR UPDATE statement and then updating or deleting rows one-by-one. Etsuro Fujita, reviewed by Rushabh Lathia, Shigeru Hanada, Kyotaro Horiguchi, Albe Laurenz, Thom Brown, and me.
* postgres_fdw: Consider foreign joining and foreign sorting together.Robert Haas2016-03-09
| | | | | | | | | | | | Commit ccd8f97922944566d26c7d90eb67ab7848ee9905 gave us the ability to request that the remote side sort the data, and, later, commit e4106b2528727c4b48639c0e12bf2f70a766b910 gave us the ability to request that the remote side perform the join for us rather than doing it locally. But we could not do both things at the same time: a remote SQL query that had an ORDER BY clause would never be a join. This commit adds that capability. Ashutosh Bapat, reviewed by me.
* postgres_fdw: When sending ORDER BY, always include NULLS FIRST/LAST.Robert Haas2016-03-04
| | | | | | | | | Previously, we included NULLS FIRST when appropriate but relied on the default behavior to be NULLS LAST. This is, however, not true for a sort in descending order and seems like a fragile assumption anyway. Report by Rajkumar Raghuwanshi. Patch by Ashutosh Bapat. Review comments from Michael Paquier and Tom Lane.
* postgres_fdw: Remove unstable regression test.Robert Haas2016-02-09
| | | | Per Tom Lane and the buildfarm.
* postgres_fdw: Push down joins to remote servers.Robert Haas2016-02-09
| | | | | | | | | | | | | | | If we've got a relatively straightforward join between two tables, this pushes that join down to the remote server instead of fetching the rows for each table and performing the join locally. Some cases are not handled yet, such as SEMI and ANTI joins. Also, we don't yet attempt to create presorted join paths or parameterized join paths even though these options do get tried for a base relation scan. Nevertheless, this seems likely to be a very significant win in many practical cases. Shigeru Hanada and Ashutosh Bapat, reviewed by Robert Haas, with additional review at various points by Tom Lane, Etsuro Fujita, KaiGai Kohei, and Jeevan Chalke.
* postgres_fdw: Avoid possible misbehavior when RETURNING tableoid column only.Robert Haas2016-02-04
| | | | | | | | deparseReturningList ended up adding up RETURNING NULL to the code, but code elsewhere saw an empty list of attributes and concluded that it should not expect tuples from the remote side. Etsuro Fujita and Robert Haas, reviewed by Thom Brown
* postgres_fdw: Allow fetch_size to be set per-table or per-server.Robert Haas2016-02-03
| | | | | | | The default fetch size of 100 rows might not be right in every environment, so allow users to configure it. Corey Huinker, reviewed by Kyotaro Horiguchi, Andres Freund, and me.
* Fix incorrect pattern-match processing in psql's \det command.Tom Lane2016-01-29
| | | | | | | | | | | | | | listForeignTables' invocation of processSQLNamePattern did not match up with the other ones that handle potentially-schema-qualified names; it failed to make use of pg_table_is_visible() and also passed the name arguments in the wrong order. Bug seems to have been aboriginal in commit 0d692a0dc9f0e532. It accidentally sort of worked as long as you didn't inquire too closely into the behavior, although the silliness was later exposed by inconsistencies in the test queries added by 59efda3e50ca4de6 (which I probably should have questioned at the time, but didn't). Per bug #13899 from Reece Hart. Patch by Reece Hart and Tom Lane. Back-patch to all affected branches.
* postgres_fdw: Consider requesting sorted data so we can do a merge join.Robert Haas2015-12-22
| | | | | | | | | | | | | | | | | | When use_remote_estimate is enabled, consider adding ORDER BY to the query we sending to the remote server so that we can use that ordered data for a merge join. Commit f18c944b6137329ac4a6b2dce5745c5dc21a8578 arranges to push down the query pathkeys, which seems like the case mostly likely to be a win, but testing shows this can sometimes win, too. For a regular table, we know which indexes are present and therefore test whether the ordering provided by each such index is useful. Here, we take the opposite approach: guess what orderings would be useful if they could be generated cheaply, and then ask the remote side what those will cost. Ashutosh Bapat, with very substantial cosmetic revisions by me. Also reviewed by Rushabh Lathia.
* Add regression tests for remote execution of extension operators/functions.Tom Lane2015-11-04
| | | | | | Rather than relying on other extensions to be available for installation, let's just add some test objects to the postgres_fdw extension itself within the regression script.
* postgres_fdw: Add ORDER BY to some remote SQL queries.Robert Haas2015-11-03
| | | | | | | | | | | | | | | | | | | | If the join problem's entire ORDER BY clause can be pushed to the remote server, consider a path that adds this ORDER BY clause. If use_remote_estimate is on, we cost this path using an additional remote EXPLAIN. If not, we just estimate that the path costs 20% more, which is intended to be large enough that we won't request a remote sort when it's not helpful, but small enough that we'll have the remote side do the sort when in doubt. In some cases, the remote sort might actually be free, because the remote query plan might happen to produce output that is ordered the way we need, but without remote estimates we have no way of knowing that. It might also be useful to request sorted output from the remote side if it enables an efficient merge join, but this patch doesn't attempt to handle that case. Ashutosh Bapat with revisions by me. Also reviewed by Fabrízio de Royes Mello and Jeevan Chalke.
* Improve handling of collations in contrib/postgres_fdw.Tom Lane2015-09-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we have a local Var of say varchar type with default collation, and we apply a RelabelType to convert that to text with default collation, we don't want to consider that as creating an FDW_COLLATE_UNSAFE situation. It should be okay to compare that to a remote Var, so long as the remote Var determines the comparison collation. (When we actually ship such an expression to the remote side, the local Var would become a Param with default collation, meaning the remote Var would in fact control the comparison collation, because non-default implicit collation overrides default implicit collation in parse_collate.c.) To fix, be more precise about what FDW_COLLATE_NONE means: it applies either to a noncollatable data type or to a collatable type with default collation, if that collation can't be traced to a remote Var. (When it can, FDW_COLLATE_SAFE is appropriate.) We were essentially using that interpretation already at the Var/Const/Param level, but we weren't bubbling it up properly. An alternative fix would be to introduce a separate FDW_COLLATE_DEFAULT value to describe the second situation, but that would add more code without changing the actual behavior, so it didn't seem worthwhile. Also, since we're clarifying the rule to be that we care about whether operator/function input collations match, there seems no need to fail immediately upon seeing a Const/Param/non-foreign-Var with nondefault collation. We only have to reject if it appears in a collation-sensitive context (for example, "var IS NOT NULL" is perfectly safe from a collation standpoint, whatever collation the var has). So just set the state to UNSAFE rather than failing immediately. Per report from Jeevan Chalke. This essentially corrects some sloppy thinking in commit ed3ddf918b59545583a4b374566bc1148e75f593, so back-patch to 9.3 where that logic appeared.
* Add support for INSERT ... ON CONFLICT DO NOTHING/UPDATE.Andres Freund2015-05-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The newly added ON CONFLICT clause allows to specify an alternative to raising a unique or exclusion constraint violation error when inserting. ON CONFLICT refers to constraints that can either be specified using a inference clause (by specifying the columns of a unique constraint) or by naming a unique or exclusion constraint. DO NOTHING avoids the constraint violation, without touching the pre-existing row. DO UPDATE SET ... [WHERE ...] updates the pre-existing tuple, and has access to both the tuple proposed for insertion and the existing tuple; the optional WHERE clause can be used to prevent an update from being executed. The UPDATE SET and WHERE clauses have access to the tuple proposed for insertion using the "magic" EXCLUDED alias, and to the pre-existing tuple using the table name or its alias. This feature is often referred to as upsert. This is implemented using a new infrastructure called "speculative insertion". It is an optimistic variant of regular insertion that first does a pre-check for existing tuples and then attempts an insert. If a violating tuple was inserted concurrently, the speculatively inserted tuple is deleted and a new attempt is made. If the pre-check finds a matching tuple the alternative DO NOTHING or DO UPDATE action is taken. If the insertion succeeds without detecting a conflict, the tuple is deemed inserted. To handle the possible ambiguity between the excluded alias and a table named excluded, and for convenience with long relation names, INSERT INTO now can alias its target table. Bumps catversion as stored rules change. Author: Peter Geoghegan, with significant contributions from Heikki Linnakangas and Andres Freund. Testing infrastructure by Jeff Janes. Reviewed-By: Heikki Linnakangas, Andres Freund, Robert Haas, Simon Riggs, Dean Rasheed, Stephen Frost and many others.
* Allow foreign tables to participate in inheritance.Tom Lane2015-03-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Foreign tables can now be inheritance children, or parents. Much of the system was already ready for this, but we had to fix a few things of course, mostly in the area of planner and executor handling of row locks. As side effects of this, allow foreign tables to have NOT VALID CHECK constraints (and hence to accept ALTER ... VALIDATE CONSTRAINT), and to accept ALTER SET STORAGE and ALTER SET WITH/WITHOUT OIDS. Continuing to disallow these things would've required bizarre and inconsistent special cases in inheritance behavior. Since foreign tables don't enforce CHECK constraints anyway, a NOT VALID one is a complete no-op, but that doesn't mean we shouldn't allow it. And it's possible that some FDWs might have use for SET STORAGE or SET WITH OIDS, though doubtless they will be no-ops for most. An additional change in support of this is that when a ModifyTable node has multiple target tables, they will all now be explicitly identified in EXPLAIN output, for example: Update on pt1 (cost=0.00..321.05 rows=3541 width=46) Update on pt1 Foreign Update on ft1 Foreign Update on ft2 Update on child3 -> Seq Scan on pt1 (cost=0.00..0.00 rows=1 width=46) -> Foreign Scan on ft1 (cost=100.00..148.03 rows=1170 width=46) -> Foreign Scan on ft2 (cost=100.00..148.03 rows=1170 width=46) -> Seq Scan on child3 (cost=0.00..25.00 rows=1200 width=46) This was done mainly to provide an unambiguous place to attach "Remote SQL" fields, but it is useful for inherited updates even when no foreign tables are involved. Shigeru Hanada and Etsuro Fujita, reviewed by Ashutosh Bapat and Kyotaro Horiguchi, some additional hacking by me
* Allow CHECK constraints to be placed on foreign tables.Tom Lane2014-12-17
| | | | | | | | | | | | | | | As with NOT NULL constraints, we consider that such constraints are merely reports of constraints that are being enforced by the remote server (or other underlying storage mechanism). Their only real use is to allow planner optimizations, for example in constraint-exclusion checks. Thus, the code changes here amount to little more than removal of the error that was formerly thrown for applying CHECK to a foreign table. (In passing, do a bit of cleanup of the ALTER FOREIGN TABLE reference page, which had accumulated some weird decisions about ordering etc.) Shigeru Hanada and Etsuro Fujita, reviewed by Kyotaro Horiguchi and Ashutosh Bapat.
* Revert misguided change to postgres_fdw FOR UPDATE/SHARE code.Tom Lane2014-12-12
| | | | | | | | | | | | | | | In commit 462bd95705a0c23ba0b0ba60a78d32566a0384c1, I changed postgres_fdw to rely on get_plan_rowmark() instead of get_parse_rowmark(). I still think that's a good idea in the long run, but as Etsuro Fujita pointed out, it doesn't work today because planner.c forces PlanRowMarks to have markType = ROW_MARK_COPY for all foreign tables. There's no urgent reason to change this in the back branches, so let's just revert that part of yesterday's commit rather than trying to design a better solution under time pressure. Also, add a regression test case showing what postgres_fdw does with FOR UPDATE/SHARE. I'd blithely assumed there was one already, else I'd have realized yesterday that this code didn't work.
* Fix mishandling of system columns in FDW queries.Tom Lane2014-11-22
| | | | | | | | | | | | | | | | | | | | postgres_fdw would send query conditions involving system columns to the remote server, even though it makes no effort to ensure that system columns other than CTID match what the remote side thinks. tableoid, in particular, probably won't match and might have some use in queries. Hence, prevent sending conditions that include non-CTID system columns. Also, create_foreignscan_plan neglected to check local restriction conditions while determining whether to set fsSystemCol for a foreign scan plan node. This again would bollix the results for queries that test a foreign table's tableoid. Back-patch the first fix to 9.3 where postgres_fdw was introduced. Back-patch the second to 9.2. The code is probably broken in 9.1 as well, but the patch doesn't apply cleanly there; given the weak state of support for FDWs in 9.1, it doesn't seem worth fixing. Etsuro Fujita, reviewed by Ashutosh Bapat, and somewhat modified by me
* Specify the port in dblink and postgres_fdw tests.Andres Freund2014-08-26
| | | | | | | | | | That allows to run those tests against a postmaster listening on a nonstandard port without requiring to export PGPORT in postmaster's environment. This still doesn't support connecting to a nondefault host without configuring it in postmaster's environment. That's harder and less frequently used though. So this is a useful step.
* Don't hardcode contrib_regression dbname in postgres_fdw and dblink tests.Andres Freund2014-08-26
| | | | | | | | | | | That allows parallel installcheck to succeed inside contrib/. The output is not particularly pretty unless make's -O option to synchronize the output is used. There's other tests, outside contrib, that use a hardcoded, non-unique, database name. Those prohibit paralell installcheck to be used across more directories; but that's something for a separate patch.
* Implement IMPORT FOREIGN SCHEMA.Tom Lane2014-07-10
| | | | | | | | | | | This command provides an automated way to create foreign table definitions that match remote tables, thereby reducing tedium and chances for error. In this patch, we provide the necessary core-server infrastructure and implement the feature fully in the postgres_fdw foreign-data wrapper. Other wrappers will throw a "feature not supported" error until/unless they are updated. Ronan Dunklau and Michael Paquier, additional work by me
* Fix contrib/postgres_fdw's remote-estimate representation of array Params.Tom Lane2014-04-16
| | | | | | | | | | | We were emitting "(SELECT null::typename)", which is usually interpreted as a scalar subselect, but not so much in the context "x = ANY(...)". This led to remote-side parsing failures when remote_estimate is enabled. A quick and ugly fix is to stick in an extra cast step, "((SELECT null::typename)::typename)". The cast will be thrown away as redundant by parse analysis, but not before it's done its job of making sure the grammar sees the ANY argument as an a_expr rather than a select_with_parens. Per an example from Hannu Krosing.
* Don't test xmin/xmax columns of a postgres_fdw foreign table.Noah Misch2014-03-23
| | | | | | Their values are unspecified and system-dependent. Per buildfarm member kouprey.
* Offer triggers on foreign tables.Noah Misch2014-03-23
| | | | | | | | | | | | | | | | | This covers all the SQL-standard trigger types supported for regular tables; it does not cover constraint triggers. The approach for acquiring the old row mirrors that for view INSTEAD OF triggers. For AFTER ROW triggers, we spool the foreign tuples to a tuplestore. This changes the FDW API contract; when deciding which columns to populate in the slot returned from data modification callbacks, writable FDWs will need to check for AFTER ROW triggers in addition to checking for a RETURNING clause. In support of the feature addition, refactor the TriggerFlags bits and the assembly of old tuples in ModifyTable. Ronan Dunklau, reviewed by KaiGai Kohei; some additional hacking by me.
* Fix contrib/postgres_fdw to handle multiple join conditions properly.Tom Lane2014-03-07
| | | | | | | | | | | | | | | | | | | | | | | | The previous coding supposed that it could consider just a single join condition in any one parameterized path for the foreign table. But in reality, the parameterized-path machinery forces all join clauses that are "movable to" the foreign table to be evaluated at that node; including clauses that we might not consider safe to send across. Such cases would result in an Assert failure in an assert-enabled build, and otherwise in sending an unsafe clause to the foreign server, which might result in errors or silently-wrong answers. A lesser problem was that the cost/rowcount estimates generated for the parameterized path failed to account for any additional join quals that get assigned to the scan. To fix, rewrite postgresGetForeignPaths so that it correctly collects all the movable quals for any one outer relation when generating parameterized paths; we'll now generate just one path per outer relation not one per join qual. Also fix bogus assumptions in postgresGetForeignPlan and estimate_path_cost_size that only safe-to-send join quals will be presented. Based on complaint from Etsuro Fujita that the path costs were being miscalculated, though this is significantly different from his proposed patch.
* Improve updatability checking for views and foreign tables.Tom Lane2013-06-12
| | | | | | | | | | | | | | | | | | | | | Extend the FDW API (which we already changed for 9.3) so that an FDW can report whether specific foreign tables are insertable/updatable/deletable. The default assumption continues to be that they're updatable if the relevant executor callback function is supplied by the FDW, but finer granularity is now possible. As a test case, add an "updatable" option to contrib/postgres_fdw. This patch also fixes the information_schema views, which previously did not think that foreign tables were ever updatable, and fixes view_is_auto_updatable() so that a view on a foreign table can be auto-updatable. initdb forced due to changes in information_schema views and the functions they rely on. This is a bit unfortunate to do post-beta1, but if we don't change this now then we'll have another API break for FDWs when we do change it. Dean Rasheed, somewhat editorialized on by Tom Lane
* Tweak postgres_fdw regression test so autovacuum doesn't change results.Tom Lane2013-06-09
| | | | | | | | | | Autovacuum occurring while the test runs could allow some of the inserts to go into recycled space, thus changing the output ordering of later queries. While we could complicate those queries to force sorting of their output rows, it doesn't seem like that would make the test better in any meaningful way, and conceivably it could hide unexpected diffs. Instead, tweak the affected queries so that the inserted rows aren't updated by the following UPDATE. Per buildfarm.
* Allow CREATE FOREIGN TABLE to include SERIAL columns.Tom Lane2013-05-15
| | | | | | | | | | | | | | | | The behavior is that the required sequence is created locally, which is appropriate because the default expression will be evaluated locally. Per gripe from Brad Nicholson that this case was refused with a confusing error message. We could have improved the error message but it seems better to just allow the case. Also, remove ALTER TABLE's arbitrary prohibition against being applied to foreign tables, which was pretty inconsistent considering we allow it for views, sequences, and other relation types that aren't even called tables. This is needed to avoid breaking pg_dump, which sometimes emits column defaults using separate ALTER TABLE commands. (I think this can happen even when the default is not associated with a sequence, so that was a pre-existing bug once we allowed column defaults for foreign tables.)
* Avoid retrieving dummy NULL columns in postgres_fdw.Tom Lane2013-03-22
| | | | | | | This should provide some marginal overall savings, since it surely takes many more cycles for the remote server to deal with the NULL columns than it takes for postgres_fdw not to emit them. But really the reason is to keep the emitted queries from looking quite so silly ...
* Redo postgres_fdw's planner code so it can handle parameterized paths.Tom Lane2013-03-21
| | | | | | | | | | | | I wasn't going to ship this without having at least some example of how to do that. This version isn't terribly bright; in particular it won't consider any combinations of multiple join clauses. Given the cost of executing a remote EXPLAIN, I'm not sure we want to be very aggressive about doing that, anyway. In support of this, refactor generate_implied_equalities_for_indexcol so that it can be used to extract equivalence clauses that aren't necessarily tied to an index.
* Introduce less-bogus handling of collations in contrib/postgres_fdw.Tom Lane2013-03-13
| | | | | | | | | | | | Treat expressions as being remotely executable only if all collations used in them are determined by Vars of the foreign table. This means that, if the foreign server gets different answers than we do, it's the user's fault for not having marked the foreign table columns with collations equivalent to the remote table's. This rule allows most simple expressions such as "var < 'constant'" to be sent to the remote side, because the constant isn't determining the collation (the Var's collation would win). There's still room for improvement, but it's hard to see how to do it without a lot more knowledge and/or assumptions about what the remote side will do.
* Fix contrib/postgres_fdw's handling of column defaults.Tom Lane2013-03-12
| | | | | | | | | Adopt the position that only locally-defined defaults matter. Any defaults defined in the remote database do not affect insertions performed through a foreign table (unless they are for columns not known to the foreign table). While it'd arguably be more useful to permit remote defaults to be used, making that work in a consistent fashion requires far more work than seems possible for 9.3.
* Avoid row-processing-order dependency in postgres_fdw regression test.Tom Lane2013-03-12
| | | | | | A test intended to provoke an error on the remote side was coded in such a way that multiple rows should be updated, so the output would vary depending on which one was processed first. Per buildfarm.
* Fix postgres_fdw's issues with inconsistent interpretation of data values.Tom Lane2013-03-11
| | | | | | | | | | | | | | | | | | | | | For datatypes whose output formatting depends on one or more GUC settings, we have to worry about whether the other server will interpret the value the same way it was meant. pg_dump has been aware of this hazard for a long time, but postgres_fdw needs to deal with it too. To fix data retrieval from the remote server, set the necessary remote GUC settings at connection startup. (We were already assuming that settings made then would persist throughout the remote session.) To fix data transmission to the remote server, temporarily force the relevant GUCs to the right values when we're about to convert any data values to text for transmission. This is all pretty grotty, and not very cheap either. It's tempting to think of defining one uber-GUC that would override any settings that might render printed data values unportable. But of course, older remote servers wouldn't know any such thing and would still need this logic. While at it, revert commit f7951eef89be78c50ea2241f593d76dfefe176c9, since this provides a real fix. (The timestamptz given in the error message returned from the "remote" server will now reliably be shown in UTC.)
* Band-aid for regression test expected-results problem with timestamptz.Tom Lane2013-03-10
| | | | | | | We probably need to tell the remote server to use specific timezone and datestyle settings, and maybe other things. But for now let's just hack the postgres_fdw regression test to not provoke failures when run in non-EST5EDT environments. Per buildfarm.
* Support writable foreign tables.Tom Lane2013-03-10
| | | | | | | | | | | This patch adds the core-system infrastructure needed to support updates on foreign tables, and extends contrib/postgres_fdw to allow updates against remote Postgres servers. There's still a great deal of room for improvement in optimization of remote updates, but at least there's basic functionality there now. KaiGai Kohei, reviewed by Alexander Korotkov and Laurenz Albe, and rather heavily revised by Tom Lane.
* Rename postgres_fdw's use_remote_explain option to use_remote_estimate.Tom Lane2013-02-23
| | | | | The new name was originally my typo, but per discussion it seems like a better name anyway. So make the code match the docs, not vice versa.
* Fix whole-row references in postgres_fdw.Tom Lane2013-02-22
| | | | | The optimization to not retrieve unnecessary columns wasn't smart enough. Noted by Thom Brown.
* Add postgres_fdw contrib module.Tom Lane2013-02-21
There's still a lot of room for improvement, but it basically works, and we need this to be present before we can do anything much with the writable-foreign-tables patch. So let's commit it and get on with testing. Shigeru Hanada, reviewed by KaiGai Kohei and Tom Lane