postgres_fdw does not support two-phase transactions, so let's add a
small negative test case to check after it. Note that this is checked
using an end-of-xact callback to ensure a proper connection cleanup with
the foreign server, which is called before checking if a server is able
to handle 2PC with max_prepared_xacts, so this test does not need an
alternate output file.
Author: Gilles Darold
Discussion: https://postgr.es/m/20191108090507.GC1768@paquier.xyz
Previously, in postgresPlanForeignModify, we planned an UPDATE operation
on a foreign table so that we transmit only columns that were explicitly
targets of the UPDATE, so as to avoid unnecessary data transmission, but
if there were BEFORE ROW UPDATE triggers on the foreign table, those
triggers might change values for non-target columns, in which case we
would miss sending changed values for those columns. Prevent optimizing
away transmitting all columns if there are BEFORE ROW UPDATE triggers on
the foreign table.
This is an oversight in commit 7cbe57c34 which added triggers on foreign
tables, so apply the patch all the way back to 9.4 where that came in.
Author: Shohei Mochizuki
Reviewed-by: Amit Langote
Discussion: https://postgr.es/m/201905270152.x4R1q3qi014550@toshiba.co.jp
foreign_grouping_ok() is willing to put fairly arbitrary expressions into
the targetlist of a remote SELECT that's doing grouping or aggregation on
the remote side, including expressions that have no foreign component to
them at all. This is possibly a bit dubious from an efficiency standpoint;
but it rises to the level of a crash-causing bug if the expression is just
a Param or non-foreign Var. In that case, the expression will necessarily
also appear in the fdw_exprs list of values we need to send to the remote
server, and then setrefs.c's set_foreignscan_references will mistakenly
replace the fdw_exprs entry with a Var referencing the targetlist result.
The root cause of this problem is bad design in commit e7cb7ee14: it put
logic into set_foreignscan_references that IMV is postgres_fdw-specific,
and yet this bug shows that it isn't postgres_fdw-specific enough. The
transformation being done on fdw_exprs assumes that fdw_exprs is to be
evaluated with the fdw_scan_tlist as input, which is not how postgres_fdw
uses it; yet it could be the right thing for some other FDW. (In the
bigger picture, setrefs.c has no business assuming this for the other
expression fields of a ForeignScan either.)
The right fix therefore would be to expand the FDW API so that the
FDW could inform setrefs.c how it intends to evaluate these various
expressions. We can't change that in the back branches though, and we
also can't just summarily change setrefs.c's behavior there, or we're
likely to break external FDWs.
As a stopgap, therefore, hack up postgres_fdw so that it won't attempt
to send targetlist entries that look exactly like the fdw_exprs entries
they'd produce. In most cases this actually produces a superior plan,
IMO, with less data needing to be transmitted and returned; so we probably
ought to think harder about whether we should ship tlist expressions at
all when they don't contain any foreign Vars or Aggs. But that's an
optimization not a bug fix so I left it for later. One case where this
produces an inferior plan is where the expression in question is actually
a GROUP BY expression: then the restriction prevents us from using remote
grouping. It might be possible to work around that (since that would
reduce to group-by-a-constant on the remote side); but it seems like a
pretty unlikely corner case, so I'm not sure it's worth expending effort
solely to improve that. In any case the right long-term answer is to fix
the API as sketched above, and then revert this hack.
Per bug #15781 from Sean Johnston. Back-patch to v10 where the problem
was introduced.
Discussion: https://postgr.es/m/15781-2601b1002bad087c@postgresql.org
Commit 3d956d9562 added support for update row movement in postgres_fdw.
This patch fixes the following issues introduced by that commit:
* When a remote partition chosen to insert routed rows into was also an
UPDATE subplan target rel that would be updated later, the UPDATE that
used a direct modification plan modified those routed rows incorrectly
because those routed rows were visible to the later UPDATE command.
The right fix for this would be to have some way in postgres_fdw in
which the later UPDATE command ignores those routed rows, but it seems
hard to do so with the current infrastructure. For now throw an error
in that case.
* When a remote partition chosen to insert routed rows into was also an
UPDATE subplan target rel, fmstate created for the UPDATE that used a
non-direct modification plan was mistakenly overridden by another
fmstate created for inserting those routed rows into the partition.
This caused 1) server crash when the partition would be updated later,
and 2) resource leak when the partition had been already updated. To
avoid that, adjust the treatment of the fmstate for the inserting. As
for #1, since we would also have the incorrectness issue as mentioned
above, error out in that case as well.
Update the docs to mention that postgres_fdw currently does not handle
the case where a remote partition chosen to insert a routed row into is
also an UPDATE subplan target rel that will be updated later.
Author: Amit Langote and Etsuro Fujita
Reviewed-by: Amit Langote
Backpatch-through: 11 where row movement in postgres_fdw was added
Discussion: https://postgr.es/m/21e7eaa4-0d4d-20c2-a1f7-c7e96f4ce440@lab.ntt.co.jp
Similarly to the set of parameters for keepalive, a connection parameter
for libpq is added as well as a backend GUC, called tcp_user_timeout.
Increasing the TCP user timeout is useful to allow a connection to
survive extended periods without end-to-end connection, and decreasing
it allows application to fail faster. By default, the parameter is 0,
which makes the connection use the system default, and follows a logic
close to the keepalive parameters in its handling. When connecting
through a Unix-socket domain, the parameters have no effect.
Author: Ryohei Nagaura
Reviewed-by: Fabien Coelho, Robert Haas, Kyotaro Horiguchi, Kirk
Jamison, Mikalai Keida, Takayuki Tsunakawa, Andrei Yahorau
Discussion: https://postgr.es/m/EDA4195584F5064680D8130B1CA91C45367328@G01JPEXMBYT04
The upper-planner pathification allows FDWs to arrange to push down
different types of upper-stage operations to the remote side. This
commit teaches postgres_fdw to do it for the (FINAL, NULL) upperrel,
which is responsible for doing LockRows, LIMIT, and/or ModifyTable.
This provides the ability for postgres_fdw to handle SELECT commands
so that it 1) skips the LockRows step (if any) (note that this is
safe since it performs early locking) and 2) pushes down the LIMIT
and/or OFFSET restrictions (if any) to the remote side. This doesn't
handle the INSERT/UPDATE/DELETE cases.
Author: Etsuro Fujita
Reviewed-By: Antonin Houska and Jeff Janes
Discussion: https://postgr.es/m/87pnz1aby9.fsf@news-spur.riddles.org.uk
This is an SQL-standard feature that allows creating columns that are
computed from expressions rather than assigned, similar to a view or
materialized view but on a column basis.
This implements one kind of generated column: stored (computed on
write). Another kind, virtual (computed on read), is planned for the
future, and some room is left for it.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/b151f851-4019-bdb1-699e-ebab07d2f40a@2ndquadrant.com
If there's only one child relation, the Append or MergeAppend isn't
doing anything useful, and can be elided. It does have a purpose
during planning though, which is to serve as a buffer between parent
and child Var numbering. Therefore we keep it all the way through
to setrefs.c, and get rid of it only after fixing references in the
plan level(s) above it. This works largely the same as setrefs.c's
ancient hack to get rid of no-op SubqueryScan nodes, and can even
share some code with that.
Note the change to make setrefs.c use apply_tlist_labeling rather than
ad-hoc code. This has the effect of propagating the child's resjunk
and ressortgroupref labels, which formerly weren't propagated when
removing a SubqueryScan. Doing that is demonstrably necessary for
the [Merge]Append cases, and seems harmless for SubqueryScan, if only
because trivial_subqueryscan is afraid to collapse cases where the
resjunk marking differs. (I suspect that restriction could now be
removed, though it's unclear that it'd make any new matches possible,
since the outer query can't have references to a child resjunk column.)
David Rowley, reviewed by Alvaro Herrera and Tomas Vondra
Discussion: https://postgr.es/m/CAKJS1f_7u8ATyJ1JGTMHFoKDvZdeF-iEBhs+sM_SXowOr9cArg@mail.gmail.com
Historically we've always materialized the full output of a CTE query,
treating WITH as an optimization fence (so that, for example, restrictions
from the outer query cannot be pushed into it). This is appropriate when
the CTE query is INSERT/UPDATE/DELETE, or is recursive; but when the CTE
query is non-recursive and side-effect-free, there's no hazard of changing
the query results by pushing restrictions down.
Another argument for materialization is that it can avoid duplicate
computation of an expensive WITH query --- but that only applies if
the WITH query is called more than once in the outer query. Even then
it could still be a net loss, if each call has restrictions that
would allow just a small part of the WITH query to be computed.
Hence, let's change the behavior for WITH queries that are non-recursive
and side-effect-free. By default, we will inline them into the outer
query (removing the optimization fence) if they are called just once.
If they are called more than once, we will keep the old behavior by
default, but the user can override this and force inlining by specifying
NOT MATERIALIZED. Lastly, the user can force the old behavior by
specifying MATERIALIZED; this would mainly be useful when the query had
deliberately been employing WITH as an optimization fence to prevent a
poor choice of plan.
Andreas Karlsson, Andrew Gierth, David Fetter
Discussion: https://postgr.es/m/87sh48ffhb.fsf@news-spur.riddles.org.uk
Up to now postgres_fdw has been using create_foreignscan_path() to
generate not only base-relation paths, but also paths for foreign joins
and foreign upperrels. This is wrong, because create_foreignscan_path()
calls get_baserel_parampathinfo() which will only do the right thing for
baserels. It accidentally fails to fail for unparameterized paths, which
are the only ones postgres_fdw (thought it) was handling, but we really
need different APIs for the baserel and join cases.
In HEAD, the best thing to do seems to be to split up the baserel,
joinrel, and upperrel cases into three functions so that they can
have different APIs. I haven't actually given create_foreign_join_path
a different API in this commit: we should spend a bit of time thinking
about just what we want to do there, since perhaps FDWs would want to
do something different from the build-up-a-join-pairwise approach that
get_joinrel_parampathinfo expects. In the meantime, since postgres_fdw
isn't prepared to generate parameterized joins anyway, just give it a
defense against trying to plan joins with lateral refs.
In addition (and this is what triggered this whole mess) fix bug #15613
from Srinivasan S A, by teaching file_fdw and postgres_fdw that plain
baserel foreign paths still have outer refs if the relation has
lateral_relids. Add some assertions in relnode.c to catch future
occurrences of the same error --- in particular, to catch other FDWs
doing that, but also as backstop against core-code mistakes like the
one fixed by commit bdd9a99aa.
Bug #15613 also needs to be fixed in the back branches, but the
appropriate fix will look quite a bit different there, since we don't
want to assume that existing FDWs get the word right away.
Discussion: https://postgr.es/m/15613-092be1be9576c728@postgresql.org
COPY can skip writing WAL when loading data on a table which has been
created in the same transaction as the one loading the data, however
this cannot work on views or foreign table as this would result in
trying to flush relation files which do not exist. So disable the
optimization so as commands are able to work the same way with any
configuration of wal_level.
Tests are added to cover the different cases, which need to have
wal_level set to minimal to allow the problem to show up, and that is
not the default configuration.
Reported-by: Luis M. Carril, Etsuro Fujita
Author: Amit Langote, Michael Paquier
Reviewed-by: Etsuro Fujita
Discussion: https://postgr.es/m/15552-c64aa14c5c22f63c@postgresql.org
Backpatch-through: 10, where support for COPY on views has been added,
while v11 has added support for COPY on foreign tables.
In commit 7012b132d0, which added aggregate
pushdown to postgres_fdw, we didn't account for the evaluation cost and the
selectivity of HAVING quals attached to ForeignPaths performing aggregate
pushdown, as core had never accounted for that for AggPaths and GroupPaths.
And we didn't set these values of the locally-checked quals (ie, fpinfo's
local_conds_cost and local_conds_sel), which were initialized to zeros, but
since estimate_path_cost_size factors in these to estimate the result size
and the evaluation cost of such a ForeignPath when the use_remote_estimate
option is enabled, this caused it to produce underestimated results in that
case.
By commit 7b6c075471 core was changed so that
it accounts for the evaluation cost and the selectivity of HAVING quals in
aggregation paths, so change the postgres_fdw's aggregate pushdown code as
well as such. This not only fixes the underestimation issue mentioned
above, but improves the estimation using local statistics in that function
when that option is disabled.
This would be a bug fix rather than an improvement, but apply it to HEAD
only to avoid destabilizing existing plan choices.
Author: Etsuro Fujita
Discussion: https://postgr.es/m/5BFD3EAD.2060301%40lab.ntt.co.jp
Previously tables declared WITH OIDS, including a significant fraction
of the catalog tables, stored the oid column not as a normal column,
but as part of the tuple header.
This special column was not shown by default, which was somewhat odd,
as it's often (consider e.g. pg_class.oid) one of the more important
parts of a row. Neither pg_dump nor COPY included the contents of the
oid column by default.
The fact that the oid column was not an ordinary column necessitated a
significant amount of special case code to support oid columns. That
already was painful for the existing, but upcoming work aiming to make
table storage pluggable, would have required expanding and duplicating
that "specialness" significantly.
WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0).
Remove it.
Removing includes:
- CREATE TABLE and ALTER TABLE syntax for declaring the table to be
WITH OIDS has been removed (WITH (oids[ = true]) will error out)
- pg_dump does not support dumping tables declared WITH OIDS and will
issue a warning when dumping one (and ignore the oid column).
- restoring an pg_dump archive with pg_restore will warn when
restoring a table with oid contents (and ignore the oid column)
- COPY will refuse to load binary dump that includes oids.
- pg_upgrade will error out when encountering tables declared WITH
OIDS, they have to be altered to remove the oid column first.
- Functionality to access the oid of the last inserted row (like
plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed.
The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false)
for CREATE TABLE) is still supported. While that requires a bit of
support code, it seems unnecessary to break applications / dumps that
do not use oids, and are explicit about not using them.
The biggest user of WITH OID columns was postgres' catalog. This
commit changes all 'magic' oid columns to be columns that are normally
declared and stored. To reduce unnecessary query breakage all the
newly added columns are still named 'oid', even if a table's column
naming scheme would indicate 'reloid' or such. This obviously
requires adapting a lot code, mostly replacing oid access via
HeapTupleGetOid() with access to the underlying Form_pg_*->oid column.
The bootstrap process now assigns oids for all oid columns in
genbki.pl that do not have an explicit value (starting at the largest
oid previously used), only oids assigned later by oids will be above
FirstBootstrapObjectId. As the oid column now is a normal column the
special bootstrap syntax for oids has been removed.
Oids are not automatically assigned during insertion anymore, all
backend code explicitly assigns oids with GetNewOidWithIndex(). For
the rare case that insertions into the catalog via SQL are called for
the new pg_nextoid() function can be used (which only works on catalog
tables).
The fact that oid columns on system tables are now normal columns
means that they will be included in the set of columns expanded
by * (i.e. SELECT * FROM pg_class will now include the table's oid,
previously it did not). It'd not technically be hard to hide oid
column by default, but that'd mean confusing behavior would either
have to be carried forward forever, or it'd cause breakage down the
line.
While it's not unlikely that further adjustments are needed, the
scope/invasiveness of the patch makes it worthwhile to get merge this
now. It's painful to maintain externally, too complicated to commit
after the code code freeze, and a dependency of a number of other
patches.
Catversion bump, for obvious reasons.
Author: Andres Freund, with contributions by John Naylor
Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
Commit f49842d, which added support for partitionwise joins, built the
child's tlist by applying adjust_appendrel_attrs() to the parent's. So in
the case where the parent's included a whole-row Var for the parent, the
child's contained a ConvertRowtypeExpr. To cope with that, that commit
added code to the planner, such as setrefs.c, but some code paths still
assumed that the tlist for a scan (or join) rel would only include Vars
and PlaceHolderVars, which was true before that commit, causing errors:
* When creating an explicit sort node for an input path for a mergejoin
path for a child join, prepare_sort_from_pathkeys() threw the 'could not
find pathkey item to sort' error.
* When deparsing a relation participating in a pushed down child join as a
subquery in contrib/postgres_fdw, get_relation_column_alias_ids() threw
the 'unexpected expression in subquery output' error.
* When performing set_plan_references() on a local join plan generated by
contrib/postgres_fdw for EvalPlanQual support for a pushed down child
join, fix_join_expr() threw the 'variable not found in subplan target
lists' error.
To fix these, two approaches have been proposed: one by Ashutosh Bapat and
one by me. While the former keeps building the child's tlist with a
ConvertRowtypeExpr, the latter builds it with a whole-row Var for the
child not to violate the planner assumption, and tries to fix it up later,
But both approaches need more work, so refuse to generate partitionwise
join paths when whole-row Vars are involved, instead. We don't need to
handle ConvertRowtypeExprs in the child's tlists for now, so this commit
also removes the changes to the planner.
Previously, partitionwise join computed attr_needed data for each child
separately, and built the child join's tlist using that data, which also
required an extra step for adding PlaceHolderVars to that tlist, but it
would be more efficient to build it from the parent join's tlist through
the adjust_appendrel_attrs() transformation. So this commit builds that
list that way, and simplifies build_joinrel_tlist() and placeholder.c as
well as part of set_append_rel_size() to basically what they were before
partitionwise join went in.
Back-patch to PG11 where partitionwise join was introduced.
Report by Rajkumar Raghuwanshi. Analysis by Ashutosh Bapat, who also
provided some of regression tests. Patch by me, reviewed by Robert Haas.
Discussion: https://postgr.es/m/CAKcux6ktu-8tefLWtQuuZBYFaZA83vUzuRd7c1YHC-yEWyYFpg@mail.gmail.com
If a view references a foreign table, and the foreign table has a
BEFORE INSERT trigger, then it's possible for a tuple inserted or
updated through the view to be changed such that it violates the
view's WITH CHECK OPTION constraint.
Before this commit, postgres_fdw handled this case inconsistently. A
RETURNING clause on the INSERT or UPDATE statement targeting the view
would cause the finally-inserted tuple to be read back, and the WITH
CHECK OPTION violation would throw an error. But without a RETURNING
clause, postgres_fdw would not read the final tuple back, and WITH
CHECK OPTION would not throw an error for the violation (or may throw
an error when there is no real violation). AFTER ROW triggers on the
foreign table had a similar effect as a RETURNING clause on the INSERT
or UPDATE statement.
To fix, this commit retrieves the attributes needed to enforce the
WITH CHECK OPTION constraint along with the attributes needed for the
RETURNING clause (if any) from the remote side. Thus, the WITH CHECK
OPTION constraint is always evaluated against the final tuple after
any triggers on the remote side.
This fix may be considered inconsistent with CHECK constraints
declared on foreign tables, which are not enforced locally at all
(because the constraint is on a remote object). The discussion
concluded that this difference is reasonable, because the WITH CHECK
OPTION is a constraint on the local view (not any remote object);
therefore it only makes sense to enforce its WITH CHECK OPTION
constraint locally.
Author: Etsuro Fujita
Reviewed-by: Arthur Zakirov, Stephen Frost
Discussion: https://www.postgresql.org/message-id/7eb58fab-fd3b-781b-ac33-f7cfec96021f%40lab.ntt.co.jp
Previously, we passed the toplevel PlannerInfo, but we actually want
to pass the relevant subroot. One problem with passing the toplevel
PlannerInfo is that the FDW which wants to push down an UPDATE or
DELETE against a join won't find the relevant joinrel there.
As of commit 1bc0100d27, postgres_fdw
tries to do exactly this and can be made to fail an assertion as a
result.
It's possible that this should be regarded as a bug fix and
back-patched to earlier releases, but for lack of a test case that
fails in earlier releases, no back-patch for now.
Etsuro Fujita, reviewed by Amit Langote.
Discussion: http://postgr.es/m/5AF43E02.30000@lab.ntt.co.jp
Without these fixes, changes to the inserted tuple made by remote
triggers are ignored when building local RETURNING tuples.
In the core code, call ExecInitRoutingInfo at a later point from
within ExecInitPartitionInfo so that the FDW callback gets invoked
after the returning list has been built. But move CheckValidResultRel
out of ExecInitRoutingInfo so that it can happen at an earlier stage.
In postgres_fdw, refactor assorted deparsing functions to work with
the RTE rather than the PlannerInfo, which saves us having to
construct a fake PlannerInfo in cases where we don't have a real one.
Then, we can pass down a constructed RTE that yields the correct
deparse result when no real one exists. Unfortunately, this
necessitates a hack that understands how the core code manages RT
indexes for update tuple routing, which is ugly, but we don't have a
better idea right now.
Original report, analysis, and patch by Etsuro Fujita. Heavily
refactored by me. Then worked over some more by Amit Langote.
Discussion: http://postgr.es/m/5AD4882B.10002@lab.ntt.co.jp
We've made multiple attempts to stabilize the plans shown by commit
1bc0100d2, with little success so far. The reason for the remaining
instability seems to be that if a transaction (such as auto-analyze)
is running concurrently with the test, then get_actual_variable_range may
return a maximum value for "T 1"."C 1" that's far away from the actual max,
as a result of our having transiently inserted such a value earlier in
the test. Because we use a non-MVCC snapshot to fetch the value (for
performance reasons), the presence of other transactions can cause that
function to return entries that are actually dead.
To fix, use a less extreme value in the earlier transient insertion, so
that whether it is visible or not won't affect the selectivity estimate.
The use of 9999 there seems to have been picked with the aid of a
dartboard anyway, rather than having a specific reason.
Discussion: https://postgr.es/m/16962.1523551784@sss.pgh.pa.us
Also enable this for postgres_fdw.
Etsuro Fujita, based on an earlier patch by Amit Langote. The larger
patch series of which this is a part has been reviewed by Amit
Langote, David Fetter, Maksim Milyutin, Álvaro Herrera, Stephen Frost,
and me. Minor documentation changes to the final version by me.
Discussion: http://postgr.es/m/29906a26-da12-8c86-4fb9-d8f88442f2b9@lab.ntt.co.jp
Since commit 7012b132d0, postgres_fdw
has been able to push down the toplevel aggregation operation to the
remote server. Commit e2f1eb0ee3 made
it possible to break down the toplevel aggregation into one
aggregate per partition. This commit lets postgres_fdw push down
aggregation in that case just as it does at the top level.
In order to make this work, this commit adds an additional argument
to the GetForeignUpperPaths FDW API. A matching argument is added
to the signature for create_upper_paths_hook. Third-party code using
either of these will need to be updated.
Also adjust create_foreignscan_plan() so that it picks up the correct
set of relids in this case.
Jeevan Chalke, reviewed by Ashutosh Bapat and by me and with some
adjustments by me. The larger patch series of which this patch is a
part was also reviewed and tested by Antonin Houska, Rajkumar
Raghuwanshi, David Rowley, Dilip Kumar, Konstantin Knizhnik, Pascal
Legrand, and Rafia Sabih.
Discussion: http://postgr.es/m/CAM2+6=V64_xhstVHie0Rz=KPEQnLJMZt_e314P0jaT_oJ9MR8A@mail.gmail.com
Discussion: http://postgr.es/m/CAM2+6=XPWujjmj5zUaBTGDoB38CemwcPmjkRy0qOcsQj_V+2sQ@mail.gmail.com
This reverts commit c2c537c56d.
It's now clear that whatever is going on there, it can't be blamed
on unexpected ANALYZE runs, because the statistics are the same
just before the failing query as they were at the start of the test.
It seems fairly hard to explain recent buildfarm failures without the
theory that something is doing an ANALYZE behind our backs. Probe
for this directly to see if it's true.
In principle the outputs of these queries should be stable, since the table
in question is small enough that ANALYZE's sample will include all rows.
But even if that turns out to be wrong, we can put up with some failures
for a bit. I don't intend to leave this here indefinitely.
Discussion: https://postgr.es/m/25502.1520277552@sss.pgh.pa.us
Commit 1bc0100d27 added this test, and
commits 882ea509fe,
958e20e42d,
4fa396464e tried to stabilize it. It's
still not stable, so keep trying.
The latest comment from Tom Lane is that disabling autovacuum seems
like a good strategy, but we might need to do it on more tables, hence
this patch.
Etsuro Fujita
Discussion: http://postgr.es/m/5A9928F1.2010206@lab.ntt.co.jp
Commit 1bc0100d27 added this test,
and commit 882ea509fe tried to
stabilize it. There were still failures, so commit
958e20e42d tried again to stabilize
it. That approach is still failing on jaguarundi, though, so
back it out and try something else. Specifically, instead of
disabling remote estimates for the table in question, let's tell
autovacuum to leave it alone.
Etsuro Fujita
Discussion: http://postgr.es/m/5A82DCCE.3060107@lab.ntt.co.jp
Even after commit 882ea509fe, some
buildfarm members are still failing in the postgres_fdw tests.
Try to fix that by disabling use of remote statistics for some
test cases.
Etsuro Fujita
Discussion: http://postgr.es/m/5A7D76CF.8080601@lab.ntt.co.jp
Commit 1bc0100d27 added these tests,
but they're not stable enough to survive in the buildfarm. Remove
CTIDs from the output in the hopes of fixing that.
Commit 0bf3ae88af allowed direct
foreign table modification; instead of fetching each row, updating
it locally, and then pushing the modification back to the remote
side, we would instead do all the work on the remote server via a
single remote UPDATE or DELETE command. However, that commit only
enabled this optimization when join tree consisted only of the
target table.
This change allows the same optimization when an UPDATE statement
has a FROM clause or a DELETE statement has a USING clause. This
works much like ordinary foreign join pushdown, in that the tables
must be on the same remote server, relevant parts of the query
must be pushdown-safe, and so forth.
Etsuro Fujita, reviewed by Ashutosh Bapat, Rushabh Lathia, and me.
Some formatting corrections by me.
Discussion: http://postgr.es/m/5A57193A.2080003@lab.ntt.co.jp
Discussion: http://postgr.es/m/b9cee735-62f8-6c07-7528-6364ce9347d0@lab.ntt.co.jp
Commit 4bbf6edfbd added a test case,
but it turns out that the test case doesn't reliably test for the
bug, and in the context of the regression test suite did not because
ANALYZE had not been run.
Report and patch by Etsuro Fujita. I added a comment along lines
previously suggested by Tom Lane.
Discussion: http://postgr.es/m/5A6195D8.8060206@lab.ntt.co.jp
When pushing down a join to a foreign server, postgres_fdw constructs
an alternative plan to be used for any EvalPlanQual rechecks that
prove to be necessary. This plan is stored as the outer subplan of
the Foreign Scan implementing the pushed-down join. Previously, this
alternative plan could have a different nominal sort ordering than its
parent, which seemed OK since there will only be one tuple per base
table anyway in the case of an EvalPlanQual recheck. Actually,
though, it caused a problem if that path was used as a building block
for the EvalPlanQual recheck plan of a higher-level foreign join,
because we could end up with a merge join one of whose inputs was not
labelled with the correct sort order. Repair by injecting an extra
Sort node into the EvalPlanQual recheck plan whenever it would
otherwise fail to be sorted at least as well as its parent Foreign
Scan.
Report by Jeff Janes. Patch by me, reviewed by Tom Lane, who also
provided the test case and comment text.
Discussion: http://postgr.es/m/CAMkU=1y2G8VOVBHv3iXU2TMAj7-RyBFFW1uhkr5sm9LQ2=X35g@mail.gmail.com
Commit 7012b132d, which added the ability to push down aggregates and
grouping to the remote server, wasn't careful to ensure that the remote
server would have the same idea we do about which columns are the grouping
columns, in cases where there are textually identical GROUP BY expressions.
Such cases typically led to "targetlist item has multiple sortgroupref
labels" errors.
To fix this reliably, switch over to using "GROUP BY column-number" syntax
rather than "GROUP BY expression" in transmitted queries, and adjust
foreign_grouping_ok() to be more careful about duplicating the sortgroupref
labeling of the local pathtarget.
Per bug #14890 from Sean Johnston. Back-patch to v10 where the buggy code
was introduced.
Jeevan Chalke, reviewed by Ashutosh Bapat
Discussion: https://postgr.es/m/20171107134948.1508.94783@wrigleys.postgresql.org
Antonin Houska reported that the planner does consider pushing
postgres_fdw_abs() to the remote side, which happens because we make
it shippable earlier in the test case file.
Jeevan Chalke provided this patch, which changes the join
condition to use random(), which is not shippable, instead.
Antonin reviewed the patch.
Discussion: http://postgr.es/m/15265.1511985971@localhost
rewriteTargetListUD's processing is dependent on the relkind of the query's
target table. That was fine at the time it was made to act that way, even
for queries on inheritance trees, because all tables in an inheritance tree
would necessarily be plain tables. However, the 9.5 feature addition
allowing some members of an inheritance tree to be foreign tables broke the
assumption that rewriteTargetListUD's output tlist could be applied to all
child tables with nothing more than column-number mapping. This led to
visible failures if foreign child tables had row-level triggers, and would
also break in cases where child tables belonged to FDWs that used methods
other than CTID for row identification.
To fix, delay running rewriteTargetListUD until after the planner has
expanded inheritance, so that it is applied separately to the (already
mapped) tlist for each child table. We can conveniently call it from
preprocess_targetlist. Refactor associated code slightly to avoid the
need to heap_open the target relation multiple times during
preprocess_targetlist. (The APIs remain a bit ugly, particularly around
the point of which steps scribble on parse->targetList and which don't.
But avoiding such scribbling would require a change in FDW callback APIs,
which is more pain than it's worth.)
Also fix ExecModifyTable to ensure that "tupleid" is reset to NULL when
we transition from rows providing a CTID to rows that don't. (That's
really an independent bug, but it manifests in much the same cases.)
Add a regression test checking one manifestation of this problem, which
was that row-level triggers on a foreign child table did not work right.
Back-patch to 9.5 where the problem was introduced.
Etsuro Fujita, reviewed by Ildus Kurbangaliev and Ashutosh Bapat
Discussion: https://postgr.es/m/20170514150525.0346ba72@postgrespro.ru
Instead of joining two partitioned tables in their entirety we can, if
it is an equi-join on the partition keys, join the matching partitions
individually. This involves teaching the planner about "other join"
rels, which are related to regular join rels in the same way that
other member rels are related to baserels. This can use significantly
more CPU time and memory than regular join planning, because there may
now be a set of "other" rels not only for every base relation but also
for every join relation. In most practical cases, this probably
shouldn't be a problem, because (1) it's probably unusual to join many
tables each with many partitions using the partition keys for all
joins and (2) if you do that scenario then you probably have a big
enough machine to handle the increased memory cost of planning and (3)
the resulting plan is highly likely to be better, so what you spend in
planning you'll make up on the execution side. All the same, for now,
turn this feature off by default.
Currently, we can only perform joins between two tables whose
partitioning schemes are absolutely identical. It would be nice to
cope with other scenarios, such as extra partitions on one side or the
other with no match on the other side, but that will have to wait for
a future patch.
Ashutosh Bapat, reviewed and tested by Rajkumar Raghuwanshi, Amit
Langote, Rafia Sabih, Thomas Munro, Dilip Kumar, Antonin Houska, Amit
Khandekar, and by me. A few final adjustments by me.
Discussion: http://postgr.es/m/CAFjFpRfQ8GrQvzp3jA2wnLqrHmaXna-urjm_UY9BqXj=EaDTSA@mail.gmail.com
Discussion: http://postgr.es/m/CAFjFpRcitjfrULr5jfuKWRPsGUX0LQ0k8-yG0Qw2+1LBGNpMdw@mail.gmail.com
If the user modifies a view that has CHECK OPTIONs and this gets
translated into a modification to an underlying relation which happens
to be a foreign table, the check options should be enforced. In the
normal code path, that was happening properly, but it was not working
properly for "direct" modification because the whole operation gets
pushed to the remote side in that case and we never have an option to
enforce the constraint against individual tuples. Fix by disabling
direct modification when there is a need to enforce CHECK OPTIONs.
Etsuro Fujita, reviewed by Kyotaro Horiguchi and by me.
Discussion: http://postgr.es/m/f8a48f54-6f02-9c8a-5250-9791603171ee@lab.ntt.co.jp
The new test cases added in commit 8bf58c0d9 turn out to have output
that can vary depending on the lc_messages setting prevailing on the
test server. Hide the remote end's error messages to ensure stable
output. This isn't a terribly desirable solution; we'd rather know
that the connection failed for the expected reason and not some other
one. But there seems little choice for the moment.
Per buildfarm.
Discussion: https://postgr.es/m/18419.1500658570@sss.pgh.pa.us
Previously, postgres_fdw would keep on using an existing connection even
if the user did ALTER SERVER or ALTER USER MAPPING commands that should
affect connection parameters. Teach it to watch for catcache invals
on these catalogs and re-establish connections when the relevant catalog
entries change. Per bug #14738 from Michal Lis.
In passing, clean up some rather crufty decisions in commit ae9bfc5d6
about where fields of ConnCacheEntry should be reset. We now reset
all the fields whenever we open a new connection.
Kyotaro Horiguchi, reviewed by Ashutosh Bapat and myself.
Back-patch to 9.3 where postgres_fdw appeared.
Discussion: https://postgr.es/m/20170710113917.7727.10247@wrigleys.postgresql.org
Objects in an extension are shippable to a foreign server if the
extension is part of the foreign server definition's shippable
extensions list. But this was not properly considered in some cases
when checking whether a join condition can be pushed to a foreign server
and the join condition uses an object from a shippable extension. So
the join would never be pushed down in those cases.
So, the list of extensions needs to be made available in fpinfo of the
relation being considered to be pushed down before any expressions are
assessed for being shippable. Fix foreign_join_ok() to do that for a
join relation.
The code to save FDW options in fpinfo is scattered at multiple places.
Bring all of that together into functions apply_server_options(),
apply_table_options(), and merge_fdw_options().
David Rowley and Ashutosh Bapat, per report from David Rowley
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
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
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
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
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