174 Commits (99cea49d6525e30bc3768e4ffb95377e7584dea1)

Author	SHA1	Message	Date
Tomas Vondra	99cea49d65	Fix copying data into slots with FDW batching ... Commit b676ac443b optimized handling of tuple slots with bulk inserts into foreign tables, so that the slots are initialized only once and reused for all batches. The data was however copied into the slots only after the initialization, inserting duplicate values when the slot gets reused. Fixed by moving the ExecCopySlot outside the init branch. The existing postgres_fdw tests failed to catch this due to inserting data into foreign tables without unique indexes, and then checking only the number of inserted rows. This adds a new test with both a unique index and a check of inserted values. Reported-by: Alexander Pyhalov Discussion: https://postgr.es/m/7a8cf8d56b3d18e5c0bccd6cd42d04ac%40postgrespro.ru	4 years ago
Tomas Vondra	cb92703384	Adjust batch size in postgres_fdw to not use too many parameters ... The FE/BE protocol identifies parameters with an Int16 index, which limits the maximum number of parameters per query to 65535. With batching added to postges_fdw this limit is much easier to hit, as the whole batch is essentially a single query, making this error much easier to hit. The failures are a bit unpredictable, because it also depends on the number of columns in the query. So instead of just failing, this patch tweaks the batch_size to not exceed the maximum number of parameters. Reported-by: Hou Zhijie <houzj.fnst@cn.fujitsu.com> Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> Discussion: https://postgr.es/m/OS0PR01MB571603973C0AC2874AD6BF2594299%40OS0PR01MB5716.jpnprd01.prod.outlook.com	4 years ago
Etsuro Fujita	f3baaf28a6	Fix rescanning of async-aware Append nodes. ... In cases where run-time pruning isn't required, the synchronous and asynchronous subplans for an async-aware Append node determined using classify_matching_subplans() should be re-used when rescanning the node, but the previous code re-determined them using that function repeatedly each time when rescanning the node, leading to incorrect results in a normal build and an Assert failure in an Assert-enabled build as that function doesn't assume that it's called repeatedly in such cases. Fix the code as mentioned above. My oversight in commit 27e1f1456. While at it, initialize async-related pointers/variables to NULL/zero explicitly in ExecInitAppend() and ExecReScanAppend(), just to be sure. (The variables would have been set to zero before we get to the latter function, but let's do so.) Reviewed-by: Kyotaro Horiguchi Discussion: https://postgr.es/m/CAPmGK16Q4B2_KY%2BJH7rb7wQbw54AUprp7TMekGTd2T1B62yysQ%40mail.gmail.com	4 years ago
Tom Lane	f61db909df	Fix postgres_fdw failure with whole-row Vars of type RECORD. ... Commit 86dc90056 expects that FDWs can cope with whole-row Vars for their tables, even if the Vars are marked with vartype RECORDOID. Previously, whole-row Vars generated by the planner had vartype equal to the relevant table's rowtype OID. (The point behind this change is to enable sharing of resjunk columns across inheritance child tables.) It turns out that postgres_fdw fails to cope with this, though through bad fortune none of its test cases exposed that. Things mostly work, but when we try to read back a value of such a Var, the expected rowtype is not available to record_in(). Fortunately, it's not difficult to hack up the tupdesc that controls this process to substitute the foreign table's rowtype for RECORDOID. Thus we can solve the runtime problem while still sharing the resjunk column with other tables. Per report from Alexander Pyhalov. Discussion: https://postgr.es/m/7817fb9ebd6661cdf9b67dec6e129a78@postgrespro.ru	4 years ago
Tom Lane	889592344c	Fix planner's row-mark code for inheritance from a foreign table. ... Commit 428b260f8 broke planning of cases where row marks are needed (SELECT FOR UPDATE, etc) and one of the query's tables is a foreign table that has regular table(s) as inheritance children. We got the reverse case right, but apparently were thinking that foreign tables couldn't be inheritance parents. Not so; so we need to be able to add a CTID junk column while adding a new child, not only a wholerow junk column. Back-patch to v12 where the faulty code came in. Amit Langote Discussion: https://postgr.es/m/CA+HiwqEmo3FV1LAQ4TVyS2h1WM=kMkZUmbNuZSCnfHvMcUcPeA@mail.gmail.com	4 years ago
Etsuro Fujita	a784859f44	Prevent asynchronous execution of direct foreign-table modifications. ... Commits 27e1f1456 and 86dc90056, which were independently discussed, cause a crash when executing an inherited foreign UPDATE/DELETE query with asynchronous execution enabled, where children of an Append node that is the direct/indirect child of the ModifyTable node are rewritten so as to modify foreign tables directly by postgresPlanDirectModify(); as in that case the direct modifications are executed asynchronously, which is not currently supported by asynchronous execution. Fix by disabling asynchronous execution of the direct modifications in that function. Author: Etsuro Fujita Reviewed-by: Amit Langote Discussion: https://postgr.es/m/CAPmGK158e9sJOfuWxfn%2B0ynrspXQU3JhNjSCbaoeSzMvnga%2Bbw%40mail.gmail.com	4 years ago
Etsuro Fujita	a363bc6da9	Fix EXPLAIN ANALYZE for async-capable nodes. ... EXPLAIN ANALYZE for an async-capable ForeignScan node associated with postgres_fdw is done just by using instrumentation for ExecProcNode() called from the node's callbacks, causing the following problems: 1) If the remote table to scan is empty, the node is incorrectly considered as "never executed" by the command even if the node is executed, as ExecProcNode() isn't called from the node's callbacks at all in that case. 2) The command fails to collect timings for things other than ExecProcNode() done in the node, such as creating a cursor for the node's remote query. To fix these problems, add instrumentation for async-capable nodes, and modify postgres_fdw accordingly. My oversight in commit 27e1f1456. While at it, update a comment for the AsyncRequest struct in execnodes.h and the documentation for the ForeignAsyncRequest API in fdwhandler.sgml to match the code in ExecAsyncAppendResponse() in nodeAppend.c, and fix typos in comments in nodeAppend.c. Per report from Andrey Lepikhov, though I didn't use his patch. Reviewed-by: Andrey Lepikhov Discussion: https://postgr.es/m/2eb662bb-105d-fc20-7412-2f027cc3ca72%40postgrespro.ru	4 years ago
Tom Lane	1273a15bf9	Disable cache clobber to avoid breaking postgres_fdw termination test. ... Commit 93f414614 improved a pre-existing test case so that it would show whether or not termination of the "remote" worker process happened. This soon exposed that, when debug_invalidate_system_caches_always (nee CLOBBER_CACHE_ALWAYS) is enabled, no such termination occurs. That's because cache invalidation forces postgres_fdw connections to be dropped at end of transaction, so that there's no worker to terminate. There's a race condition as to whether the worker will manage to get out of the BackendStatusArray before we look, but at least on buildfarm member hyrax, it's failed twice in two attempts. Rather than re-lobotomizing the test, let's fix this by transiently disabling debug_invalidate_system_caches_always. (Hooray for that being just a GUC nowadays, rather than a compile-time option.) If this proves not to be enough to make the test stable, we can do the other thing instead. Discussion: https://postgr.es/m/3854538.1620081771@sss.pgh.pa.us	4 years ago
Fujii Masao	8e9ea08bae	Don't pass "ONLY" options specified in TRUNCATE to foreign data wrapper. ... Commit 8ff1c94649 allowed TRUNCATE command to truncate foreign tables. Previously the information about "ONLY" options specified in TRUNCATE command were passed to the foreign data wrapper. Then postgres_fdw constructed the TRUNCATE command to issue the remote server and included "ONLY" options in it based on the passed information. On the other hand, "ONLY" options specified in SELECT, UPDATE or DELETE have no effect when accessing or modifying the remote table, i.e., are not passed to the foreign data wrapper. So it's inconsistent to make only TRUNCATE command pass the "ONLY" options to the foreign data wrapper. Therefore this commit changes the TRUNCATE command so that it doesn't pass the "ONLY" options to the foreign data wrapper, for the consistency with other statements. Also this commit changes postgres_fdw so that it always doesn't include "ONLY" options in the TRUNCATE command that it constructs. Author: Fujii Masao Reviewed-by: Bharath Rupireddy, Kyotaro Horiguchi, Justin Pryzby, Zhihong Yu Discussion: https://postgr.es/m/551ed8c1-f531-818b-664a-2cecdab99cd8@oss.nttdata.com	4 years ago
Michael Paquier	93f4146144	Simplify tests of postgres_fdw terminating connections ... The tests introduced in 32a9c0b for connections broken and re-established rely on pg_terminate_backend() for their logic. When these were introduced, this function simply sent a signal to a backend without waiting for the operation to complete, and the tests repeatedly looked at pg_stat_activity to check if the operation was completed or not. Since aaf0432, it is possible to define a timeout to make pg_terminate_backend() wait for a certain duration, so make use of it, with a timeout reasonably large enough (3min) to give enough room for the tests to pass even on slow machines. Some measurements show that the tests of postgres_fdw are much faster with this change. For example, on my laptop, they now take 4s instead of 6s. Author: Bharath Rupireddy Discussion: https://postgr.es/m/CALj2ACXGY_EfGrMTjKjHy2zi-u1u9rdeioU_fro0T6Jo8t56KQ@mail.gmail.com	4 years ago
Fujii Masao	8ff1c94649	Allow TRUNCATE command to truncate foreign tables. ... This commit introduces new foreign data wrapper API for TRUNCATE. It extends TRUNCATE command so that it accepts foreign tables as the targets to truncate and invokes that API. Also it extends postgres_fdw so that it can issue TRUNCATE command to foreign servers, by adding new routine for that TRUNCATE API. The information about options specified in TRUNCATE command, e.g., ONLY, CACADE, etc is passed to FDW via API. The list of foreign tables to truncate is also passed to FDW. FDW truncates the foreign data sources that the passed foreign tables specify, based on those information. For example, postgres_fdw constructs TRUNCATE command using them and issues it to the foreign server. For performance, TRUNCATE command invokes the FDW routine for TRUNCATE once per foreign server that foreign tables to truncate belong to. Author: Kazutaka Onishi, Kohei KaiGai, slightly modified by Fujii Masao Reviewed-by: Bharath Rupireddy, Michael Paquier, Zhihong Yu, Alvaro Herrera, Stephen Frost, Ashutosh Bapat, Amit Langote, Daniel Gustafsson, Ibrar Ahmed, Fujii Masao Discussion: https://postgr.es/m/CAOP8fzb_gkReLput7OvOK+8NHgw-RKqNv59vem7=524krQTcWA@mail.gmail.com Discussion: https://postgr.es/m/CAJuF6cMWDDqU-vn_knZgma+2GMaout68YUgn1uyDnexRhqqM5Q@mail.gmail.com	5 years ago
Peter Eisentraut	5c55dc8b47	libpq: Set Server Name Indication (SNI) for SSL connections ... By default, have libpq set the TLS extension "Server Name Indication" (SNI). This allows an SNI-aware SSL proxy to route connections. (This requires a proxy that is aware of the PostgreSQL protocol, not just any SSL proxy.) In the future, this could also allow the server to use different SSL certificates for different host specifications. (That would require new server functionality. This would be the client-side functionality for that.) Since SNI makes the host name appear in cleartext in the network traffic, this might be undesirable in some cases. Therefore, also add a libpq connection option "sslsni" to turn it off. Discussion: https://www.postgresql.org/message-id/flat/7289d5eb-62a5-a732-c3b9-438cee2cb709%40enterprisedb.com	5 years ago
Fujii Masao	a3740c48eb	postgres_fdw: Allow partitions specified in LIMIT TO to be imported. ... Commit f49bcd4ef3 disallowed postgres_fdw to import table partitions. Because all data can be accessed through the partitioned table which is the root of the partitioning hierarchy, importing only partitioned table should allow access to all the data without creating extra objects. This is a reasonable default when importing a whole schema. But there may be the case where users want to explicitly import one of a partitioned tables' partitions. For that use case, this commit allows postgres_fdw to import tables or foreign tables which are partitions of some other table only when they are explicitly specified in LIMIT TO clause. It doesn't change the behavior that any partitions not specified in LIMIT TO are automatically excluded in IMPORT FOREIGN SCHEMA command. Author: Matthias van de Meent Reviewed-by: Bernd Helmle, Amit Langote, Michael Paquier, Fujii Masao Discussion: https://postgr.es/m/CAEze2Whwg4i=mzApMe+PXxCEfgoZmHGqdqQFW7J4bmj_5p6t1A@mail.gmail.com	5 years ago
Fujii Masao	b1be3074ac	postgres_fdw: Add option to control whether to keep connections open. ... This commit adds a new option keep_connections that controls whether postgres_fdw keeps the connections to the foreign server open so that the subsequent queries can re-use them. This option can only be specified for a foreign server. The default is on. If set to off, all connections to the foreign server will be discarded at the end of transaction. Closed connections will be re-established when they are necessary by future queries using a foreign table. This option is useful, for example, when users want to prevent the connections from eating up the foreign servers connections capacity. Author: Bharath Rupireddy Reviewed-by: Alexey Kondratov, Vignesh C, Fujii Masao Discussion: https://postgr.es/m/CALj2ACVvrp5=AVp2PupEm+nAC8S4buqR3fJMmaCoc7ftT0aD2A@mail.gmail.com	5 years ago
David Rowley	9eacee2e62	Add Result Cache executor node (take 2) ... Here we add a new executor node type named "Result Cache". The planner can include this node type in the plan to have the executor cache the results from the inner side of parameterized nested loop joins. This allows caching of tuples for sets of parameters so that in the event that the node sees the same parameter values again, it can just return the cached tuples instead of rescanning the inner side of the join all over again. Internally, result cache uses a hash table in order to quickly find tuples that have been previously cached. For certain data sets, this can significantly improve the performance of joins. The best cases for using this new node type are for join problems where a large portion of the tuples from the inner side of the join have no join partner on the outer side of the join. In such cases, hash join would have to hash values that are never looked up, thus bloating the hash table and possibly causing it to multi-batch. Merge joins would have to skip over all of the unmatched rows. If we use a nested loop join with a result cache, then we only cache tuples that have at least one join partner on the outer side of the join. The benefits of using a parameterized nested loop with a result cache increase when there are fewer distinct values being looked up and the number of lookups of each value is large. Also, hash probes to lookup the cache can be much faster than the hash probe in a hash join as it's common that the result cache's hash table is much smaller than the hash join's due to result cache only caching useful tuples rather than all tuples from the inner side of the join. This variation in hash probe performance is more significant when the hash join's hash table no longer fits into the CPU's L3 cache, but the result cache's hash table does. The apparent "random" access of hash buckets with each hash probe can cause a poor L3 cache hit ratio for large hash tables. Smaller hash tables generally perform better. The hash table used for the cache limits itself to not exceeding work_mem * hash_mem_multiplier in size. We maintain a dlist of keys for this cache and when we're adding new tuples and realize we've exceeded the memory budget, we evict cache entries starting with the least recently used ones until we have enough memory to add the new tuples to the cache. For parameterized nested loop joins, we now consider using one of these result cache nodes in between the nested loop node and its inner node. We determine when this might be useful based on cost, which is primarily driven off of what the expected cache hit ratio will be. Estimating the cache hit ratio relies on having good distinct estimates on the nested loop's parameters. For now, the planner will only consider using a result cache for parameterized nested loop joins. This works for both normal joins and also for LATERAL type joins to subqueries. It is possible to use this new node for other uses in the future. For example, to cache results from correlated subqueries. However, that's not done here due to some difficulties obtaining a distinct estimation on the outer plan to calculate the estimated cache hit ratio. Currently we plan the inner plan before planning the outer plan so there is no good way to know if a result cache would be useful or not since we can't estimate the number of times the subplan will be called until the outer plan is generated. The functionality being added here is newly introducing a dependency on the return value of estimate_num_groups() during the join search. Previously, during the join search, we only ever needed to perform selectivity estimations. With this commit, we need to use estimate_num_groups() in order to estimate what the hit ratio on the result cache will be. In simple terms, if we expect 10 distinct values and we expect 1000 outer rows, then we'll estimate the hit ratio to be 99%. Since cache hits are very cheap compared to scanning the underlying nodes on the inner side of the nested loop join, then this will significantly reduce the planner's cost for the join. However, it's fairly easy to see here that things will go bad when estimate_num_groups() incorrectly returns a value that's significantly lower than the actual number of distinct values. If this happens then that may cause us to make use of a nested loop join with a result cache instead of some other join type, such as a merge or hash join. Our distinct estimations have been known to be a source of trouble in the past, so the extra reliance on them here could cause the planner to choose slower plans than it did previous to having this feature. Distinct estimations are also fairly hard to estimate accurately when several tables have been joined already or when a WHERE clause filters out a set of values that are correlated to the expressions we're estimating the number of distinct value for. For now, the costing we perform during query planning for result caches does put quite a bit of faith in the distinct estimations being accurate. When these are accurate then we should generally see faster execution times for plans containing a result cache. However, in the real world, we may find that we need to either change the costings to put less trust in the distinct estimations being accurate or perhaps even disable this feature by default. There's always an element of risk when we teach the query planner to do new tricks that it decides to use that new trick at the wrong time and causes a regression. Users may opt to get the old behavior by turning the feature off using the enable_resultcache GUC. Currently, this is enabled by default. It remains to be seen if we'll maintain that setting for the release. Additionally, the name "Result Cache" is the best name I could think of for this new node at the time I started writing the patch. Nobody seems to strongly dislike the name. A few people did suggest other names but no other name seemed to dominate in the brief discussion that there was about names. Let's allow the beta period to see if the current name pleases enough people. If there's some consensus on a better name, then we can change it before the release. Please see the 2nd discussion link below for the discussion on the "Result Cache" name. Author: David Rowley Reviewed-by: Andy Fan, Justin Pryzby, Zhihong Yu, Hou Zhijie Tested-By: Konstantin Knizhnik Discussion: https://postgr.es/m/CAApHDvrPcQyQdWERGYWx8J%2B2DLUNgXu%2BfOSbQ1UscxrunyXyrQ%40mail.gmail.com Discussion: https://postgr.es/m/CAApHDvq=yQXr5kqhRviT2RhNKwToaWr9JAN5t+5_PzhuRJ3wvg@mail.gmail.com	5 years ago
David Rowley	28b3e3905c	Revert b6002a796 ... This removes "Add Result Cache executor node". It seems that something weird is going on with the tracking of cache hits and misses as highlighted by many buildfarm animals. It's not yet clear what the problem is as other parts of the plan indicate that the cache did work correctly, it's just the hits and misses that were being reported as 0. This is especially a bad time to have the buildfarm so broken, so reverting before too many more animals go red. Discussion: https://postgr.es/m/CAApHDvq_hydhfovm4=izgWs+C5HqEeRScjMbOgbpC-jRAeK3Yw@mail.gmail.com	5 years ago
David Rowley	b6002a796d	Add Result Cache executor node ... Here we add a new executor node type named "Result Cache". The planner can include this node type in the plan to have the executor cache the results from the inner side of parameterized nested loop joins. This allows caching of tuples for sets of parameters so that in the event that the node sees the same parameter values again, it can just return the cached tuples instead of rescanning the inner side of the join all over again. Internally, result cache uses a hash table in order to quickly find tuples that have been previously cached. For certain data sets, this can significantly improve the performance of joins. The best cases for using this new node type are for join problems where a large portion of the tuples from the inner side of the join have no join partner on the outer side of the join. In such cases, hash join would have to hash values that are never looked up, thus bloating the hash table and possibly causing it to multi-batch. Merge joins would have to skip over all of the unmatched rows. If we use a nested loop join with a result cache, then we only cache tuples that have at least one join partner on the outer side of the join. The benefits of using a parameterized nested loop with a result cache increase when there are fewer distinct values being looked up and the number of lookups of each value is large. Also, hash probes to lookup the cache can be much faster than the hash probe in a hash join as it's common that the result cache's hash table is much smaller than the hash join's due to result cache only caching useful tuples rather than all tuples from the inner side of the join. This variation in hash probe performance is more significant when the hash join's hash table no longer fits into the CPU's L3 cache, but the result cache's hash table does. The apparent "random" access of hash buckets with each hash probe can cause a poor L3 cache hit ratio for large hash tables. Smaller hash tables generally perform better. The hash table used for the cache limits itself to not exceeding work_mem * hash_mem_multiplier in size. We maintain a dlist of keys for this cache and when we're adding new tuples and realize we've exceeded the memory budget, we evict cache entries starting with the least recently used ones until we have enough memory to add the new tuples to the cache. For parameterized nested loop joins, we now consider using one of these result cache nodes in between the nested loop node and its inner node. We determine when this might be useful based on cost, which is primarily driven off of what the expected cache hit ratio will be. Estimating the cache hit ratio relies on having good distinct estimates on the nested loop's parameters. For now, the planner will only consider using a result cache for parameterized nested loop joins. This works for both normal joins and also for LATERAL type joins to subqueries. It is possible to use this new node for other uses in the future. For example, to cache results from correlated subqueries. However, that's not done here due to some difficulties obtaining a distinct estimation on the outer plan to calculate the estimated cache hit ratio. Currently we plan the inner plan before planning the outer plan so there is no good way to know if a result cache would be useful or not since we can't estimate the number of times the subplan will be called until the outer plan is generated. The functionality being added here is newly introducing a dependency on the return value of estimate_num_groups() during the join search. Previously, during the join search, we only ever needed to perform selectivity estimations. With this commit, we need to use estimate_num_groups() in order to estimate what the hit ratio on the result cache will be. In simple terms, if we expect 10 distinct values and we expect 1000 outer rows, then we'll estimate the hit ratio to be 99%. Since cache hits are very cheap compared to scanning the underlying nodes on the inner side of the nested loop join, then this will significantly reduce the planner's cost for the join. However, it's fairly easy to see here that things will go bad when estimate_num_groups() incorrectly returns a value that's significantly lower than the actual number of distinct values. If this happens then that may cause us to make use of a nested loop join with a result cache instead of some other join type, such as a merge or hash join. Our distinct estimations have been known to be a source of trouble in the past, so the extra reliance on them here could cause the planner to choose slower plans than it did previous to having this feature. Distinct estimations are also fairly hard to estimate accurately when several tables have been joined already or when a WHERE clause filters out a set of values that are correlated to the expressions we're estimating the number of distinct value for. For now, the costing we perform during query planning for result caches does put quite a bit of faith in the distinct estimations being accurate. When these are accurate then we should generally see faster execution times for plans containing a result cache. However, in the real world, we may find that we need to either change the costings to put less trust in the distinct estimations being accurate or perhaps even disable this feature by default. There's always an element of risk when we teach the query planner to do new tricks that it decides to use that new trick at the wrong time and causes a regression. Users may opt to get the old behavior by turning the feature off using the enable_resultcache GUC. Currently, this is enabled by default. It remains to be seen if we'll maintain that setting for the release. Additionally, the name "Result Cache" is the best name I could think of for this new node at the time I started writing the patch. Nobody seems to strongly dislike the name. A few people did suggest other names but no other name seemed to dominate in the brief discussion that there was about names. Let's allow the beta period to see if the current name pleases enough people. If there's some consensus on a better name, then we can change it before the release. Please see the 2nd discussion link below for the discussion on the "Result Cache" name. Author: David Rowley Reviewed-by: Andy Fan, Justin Pryzby, Zhihong Yu Tested-By: Konstantin Knizhnik Discussion: https://postgr.es/m/CAApHDvrPcQyQdWERGYWx8J%2B2DLUNgXu%2BfOSbQ1UscxrunyXyrQ%40mail.gmail.com Discussion: https://postgr.es/m/CAApHDvq=yQXr5kqhRviT2RhNKwToaWr9JAN5t+5_PzhuRJ3wvg@mail.gmail.com	5 years ago
Tom Lane	86dc90056d	Rework planning and execution of UPDATE and DELETE. ... This patch makes two closely related sets of changes: 1. For UPDATE, the subplan of the ModifyTable node now only delivers the new values of the changed columns (i.e., the expressions computed in the query's SET clause) plus row identity information such as CTID. ModifyTable must re-fetch the original tuple to merge in the old values of any unchanged columns. The core advantage of this is that the changed columns are uniform across all tables of an inherited or partitioned target relation, whereas the other columns might not be. A secondary advantage, when the UPDATE involves joins, is that less data needs to pass through the plan tree. The disadvantage of course is an extra fetch of each tuple to be updated. However, that seems to be very nearly free in context; even worst-case tests don't show it to add more than a couple percent to the total query cost. At some point it might be interesting to combine the re-fetch with the tuple access that ModifyTable must do anyway to mark the old tuple dead; but that would require a good deal of refactoring and it seems it wouldn't buy all that much, so this patch doesn't attempt it. 2. For inherited UPDATE/DELETE, instead of generating a separate subplan for each target relation, we now generate a single subplan that is just exactly like a SELECT's plan, then stick ModifyTable on top of that. To let ModifyTable know which target relation a given incoming row refers to, a tableoid junk column is added to the row identity information. This gets rid of the horrid hack that was inheritance_planner(), eliminating O(N^2) planning cost and memory consumption in cases where there were many unprunable target relations. Point 2 of course requires point 1, so that there is a uniform definition of the non-junk columns to be returned by the subplan. We can't insist on uniform definition of the row identity junk columns however, if we want to keep the ability to have both plain and foreign tables in a partitioning hierarchy. Since it wouldn't scale very far to have every child table have its own row identity column, this patch includes provisions to merge similar row identity columns into one column of the subplan result. In particular, we can merge the whole-row Vars typically used as row identity by FDWs into one column by pretending they are type RECORD. (It's still okay for the actual composite Datums to be labeled with the table's rowtype OID, though.) There is more that can be done to file down residual inefficiencies in this patch, but it seems to be committable now. FDW authors should note several API changes: * The argument list for AddForeignUpdateTargets() has changed, and so has the method it must use for adding junk columns to the query. Call add_row_identity_var() instead of manipulating the parse tree directly. You might want to reconsider exactly what you're adding, too. * PlanDirectModify() must now work a little harder to find the ForeignScan plan node; if the foreign table is part of a partitioning hierarchy then the ForeignScan might not be the direct child of ModifyTable. See postgres_fdw for sample code. * To check whether a relation is a target relation, it's no longer sufficient to compare its relid to root->parse->resultRelation. Instead, check it against all_result_relids or leaf_result_relids, as appropriate. Amit Langote and Tom Lane Discussion: https://postgr.es/m/CA+HiwqHpHdqdDn48yCEhynnniahH78rwcrv1rEX65-fsZGBOLQ@mail.gmail.com	5 years ago
Etsuro Fujita	27e1f14563	Add support for asynchronous execution. ... This implements asynchronous execution, which runs multiple parts of a non-parallel-aware Append concurrently rather than serially to improve performance when possible. Currently, the only node type that can be run concurrently is a ForeignScan that is an immediate child of such an Append. In the case where such ForeignScans access data on different remote servers, this would run those ForeignScans concurrently, and overlap the remote operations to be performed simultaneously, so it'll improve the performance especially when the operations involve time-consuming ones such as remote join and remote aggregation. We may extend this to other node types such as joins or aggregates over ForeignScans in the future. This also adds the support for postgres_fdw, which is enabled by the table-level/server-level option "async_capable". The default is false. Robert Haas, Kyotaro Horiguchi, Thomas Munro, and myself. This commit is mostly based on the patch proposed by Robert Haas, but also uses stuff from the patch proposed by Kyotaro Horiguchi and from the patch proposed by Thomas Munro. Reviewed by Kyotaro Horiguchi, Konstantin Knizhnik, Andrey Lepikhov, Movead Li, Thomas Munro, Justin Pryzby, and others. Discussion: https://postgr.es/m/CA%2BTgmoaXQEt4tZ03FtQhnzeDEMzBck%2BLrni0UWHVVgOTnA6C1w%40mail.gmail.com Discussion: https://postgr.es/m/CA%2BhUKGLBRyu0rHrDCMC4%3DRn3252gogyp1SjOgG8SEKKZv%3DFwfQ%40mail.gmail.com Discussion: https://postgr.es/m/20200228.170650.667613673625155850.horikyota.ntt%40gmail.com	5 years ago
Amit Kapila	13cb5bd846	Remove extra semicolon in postgres_fdw tests. ... Author: Suraj Kharage Reviewed-by: Bharath Rupireddy, Vignesh C Discussion: https://postgr.es/m/CAF1DzPWRfxUeH-wShz7P_pK5Tx6M_nEK+TkS8gn5ngvg07Q5=g@mail.gmail.com	5 years ago
Michael Paquier	0ba71107ef	Revert changes for SSL compression in libpq ... This partially reverts 096bbf7 and 9d2d457, undoing the libpq changes as it could cause breakages in distributions that share one single libpq version across multiple major versions of Postgres for extensions and applications linking to that. Note that the backend is unchanged here, and it still disables SSL compression while simplifying the underlying catalogs that tracked if compression was enabled or not for a SSL connection. Per discussion with Tom Lane and Daniel Gustafsson. Discussion: https://postgr.es/m/YEbq15JKJwIX+S6m@paquier.xyz	5 years ago
Michael Paquier	096bbf7c93	Switch back sslcompression to be a normal input field in libpq ... Per buildfarm member crake, any servers including a postgres_fdw server with this option set would fail to do a pg_upgrade properly as the option got hidden in f9264d1 by becoming a debug option, making the restore of the FDW server fail. This changes back the option in libpq to be visible, but still inactive to fix this upgrade issue. Discussion: https://postgr.es/m/YEbq15JKJwIX+S6m@paquier.xyz	5 years ago
Michael Paquier	f9264d1524	Remove support for SSL compression ... PostgreSQL disabled compression as of e3bdb2d and the documentation recommends against using it since. Additionally, SSL compression has been disabled in OpenSSL since version 1.1.0, and was disabled in many distributions long before that. The most recent TLS version, TLSv1.3, disallows compression at the protocol level. This commit removes the feature itself, removing support for the libpq parameter sslcompression (parameter still listed for compatibility reasons with existing connection strings, just ignored), and removes the equivalent field in pg_stat_ssl and de facto PgBackendSSLStatus. Note that, on top of removing the ability to activate compression by configuration, compression is actively disabled in both frontend and backend to avoid overrides from local configurations. A TAP test is added for deprecated SSL parameters to check after backwards compatibility. Bump catalog version. Author: Daniel Gustafsson Reviewed-by: Peter Eisentraut, Magnus Hagander, Michael Paquier Discussion: https://postgr.es/m/7E384D48-11C5-441B-9EC3-F7DB1F8518F6@yesql.se	5 years ago
Peter Eisentraut	f5465fade9	Allow specifying CRL directory ... Add another method to specify CRLs, hashed directory method, for both server and client side. This offers a means for server or libpq to load only CRLs that are required to verify a certificate. The CRL directory is specifed by separate GUC variables or connection options ssl_crl_dir and sslcrldir, alongside the existing ssl_crl_file and sslcrl, so both methods can be used at the same time. Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/20200731.173911.904649928639357911.horikyota.ntt@gmail.com	5 years ago
Tomas Vondra	927f453a94	Fix tuple routing to initialize batching only for inserts ... A cross-partition update on a partitioned table is implemented as a delete followed by an insert. With foreign partitions, this was however causing issues, because the FDW and core may disagree on when to enable batching. postgres_fdw was only allowing batching for plain inserts (CMD_INSERT) while core was trying to batch the insert component of the cross-partition update. Fix by restricting core to apply batching only to plain CMD_INSERT queries. It's possible to allow batching for cross-partition updates, but that will require more extensive changes, so better to leave that for a separate patch. Author: Amit Langote Reviewed-by: Tomas Vondra, Takayuki Tsunakawa Discussion: https://postgr.es/m/20200628151002.7x5laxwpgvkyiu3q@development	5 years ago
Etsuro Fujita	5e7fa189ee	postgres_fdw: Fix assertion in estimate_path_cost_size(). ... Commit 08d2d58a2 added an assertion assuming that the retrieved_rows estimate for a foreign relation, which is re-used to cost pre-sorted foreign paths with local stats, is set to at least one row in estimate_path_cost_size(), which isn't correct because if the relation is a foreign table with tuples=0, the estimate would be set to 0 there when not using remote estimates. Per bug #16807 from Alexander Lakhin. Back-patch to v13 where the aforementioned commit went in. Author: Etsuro Fujita Reviewed-by: Kyotaro Horiguchi Discussion: https://postgr.es/m/16807-9fe4e08fbaa5c7ce%40postgresql.org	5 years ago
Fujii Masao	f77717b298	postgres_fdw: Fix tests for CLOBBER_CACHE_ALWAYS. ... The regression tests added in commits 708d165ddb and 411ae64997 caused buildfarm failures when CLOBBER_CACHE_ALWAYS was enabled. This commit stabilizes those tests. The foreign server connections established by postgres_fdw behaves differently depending on whether CLOBBER_CACHE_ALWAYS is enabled or not. If it's not enabled, those connections are cached. On the other hand, if it's enabled, when the connections are established outside transaction block, they are not cached (i.e., they are immediately closed at the end of query that established them). So the subsequent postgres_fdw_get_connections() cannot list those connections and postgres_fdw_disconnect() cannot close them (because they are already closed). When the connections are established inside transaction block, they are cached whether CLOBBER_CACHE_ALWAYS was enabled or not. But if it's enabled, they are immediately marked as invalid, otherwise not. This causes the subsequent postgres_fdw_get_connections() to return different result in "valid" column depending on whether CLOBBER_CACHE_ALWAYS was enabled or not. This commit prevents the above differences of behavior from affecting the regression tests. Per buildfarm failure on trilobite. Original patch by Bharath Rupireddy. I (Fujii Masao) extracted the regression test fix from that and revised it a bit. Reported-by: Tom Lane Author: Bharath Rupireddy Reviewed-by: Fujii Masao Discussion: https://postgr.es/m/2688508.1611865371@sss.pgh.pa.us	5 years ago
Fujii Masao	0c3fc09fe3	postgres_fdw: Fix test failure with -DENFORCE_REGRESSION_TEST_NAME_RESTRICTIONS ... The roles created by regression test should have names starting with "regress_", and the test introduced in commit 411ae64997 did not do that. Per buildfarm member longfin. Discussion: https://postgr.es/m/73fc5ae4-3c54-1262-4533-f8c547de2e60@oss.nttdata.com	5 years ago
Fujii Masao	6adc5376dc	postgres_fdw: Stabilize regression test for postgres_fdw_disconnect_all(). ... The regression test added in commit 411ae64997 caused buildfarm failures. The cause of them was that the order of warning messages output in the test was not stable. To fix this, this commit sets client_min_messages to ERROR temporarily when performing the test generating those warnings. Per buildfarm failures. Discussion: https://postgr.es/m/2147113.1611644754@sss.pgh.pa.us	5 years ago
Fujii Masao	411ae64997	postgres_fdw: Add functions to discard cached connections. ... This commit introduces two new functions postgres_fdw_disconnect() and postgres_fdw_disconnect_all(). The former function discards the cached connections to the specified foreign server. The latter discards all the cached connections. If the connection is used in the current transaction, it's not closed and a warning message is emitted. For example, these functions are useful when users want to explicitly close the foreign server connections that are no longer necessary and then to prevent them from eating up the foreign servers connections capacity. Author: Bharath Rupireddy, tweaked a bit by Fujii Masao Reviewed-by: Alexey Kondratov, Zhijie Hou, Zhihong Yu, Fujii Masao Discussion: https://postgr.es/m/CALj2ACVvrp5=AVp2PupEm+nAC8S4buqR3fJMmaCoc7ftT0aD2A@mail.gmail.com	5 years ago
Tomas Vondra	b663a41363	Implement support for bulk inserts in postgres_fdw ... Extends the FDW API to allow batching inserts into foreign tables. That is usually much more efficient than inserting individual rows, due to high latency for each round-trip to the foreign server. It was possible to implement something similar in the regular FDW API, but it was inconvenient and there were issues with reporting the number of actually inserted rows etc. This extends the FDW API with two new functions: * GetForeignModifyBatchSize - allows the FDW picking optimal batch size * ExecForeignBatchInsert - inserts a batch of rows at once Currently, only INSERT queries support batching. Support for DELETE and UPDATE may be added in the future. This also implements batching for postgres_fdw. The batch size may be specified using "batch_size" option both at the server and table level. The initial patch version was written by me, but it was rewritten and improved in many ways by Takayuki Tsunakawa. Author: Takayuki Tsunakawa Reviewed-by: Tomas Vondra, Amit Langote Discussion: https://postgr.es/m/20200628151002.7x5laxwpgvkyiu3q@development	5 years ago
Fujii Masao	708d165ddb	postgres_fdw: Add function to list cached connections to foreign servers. ... This commit adds function postgres_fdw_get_connections() to return the foreign server names of all the open connections that postgres_fdw established from the local session to the foreign servers. This function also returns whether each connection is valid or not. This function is useful when checking all the open foreign server connections. If we found some connection to drop, from the result of function, probably we can explicitly close them by the function that upcoming commit will add. This commit bumps the version of postgres_fdw to 1.1 since it adds new function. Author: Bharath Rupireddy, tweaked by Fujii Masao Reviewed-by: Zhijie Hou, Alexey Kondratov, Zhihong Yu, Fujii Masao Discussion: https://postgr.es/m/2d5cb0b3-a6e8-9bbb-953f-879f47128faa@oss.nttdata.com	5 years ago
Fujii Masao	e3ebcca843	postgres_fdw: Fix connection leak. ... In postgres_fdw, the cached connections to foreign servers will not be closed until the local session exits if the user mappings or foreign servers that those connections depend on are dropped. Those connections can be leaked. To fix that connection leak issue, after a change to a pg_foreign_server or pg_user_mapping catalog entry, this commit makes postgres_fdw close the connections depending on that entry immediately if current transaction has not used those connections yet. Otherwise, mark those connections as invalid and then close them at the end of current transaction, since they cannot be closed in the midst of the transaction using them. Closed connections will be remade at the next opportunity if necessary. Back-patch to all supported branches. Author: Bharath Rupireddy Reviewed-by: Zhihong Yu, Zhijie Hou, Fujii Masao Discussion: https://postgr.es/m/CALj2ACVNcGH_6qLY-4_tXz8JLvA+4yeBThRfxMz7Oxbk1aHcpQ@mail.gmail.com	5 years ago
Tom Lane	85d08b8b72	Band-aid new postgres_fdw test case to remove error text dependency. ... Buildfarm member lorikeet is still failing the test from commit 32a9c0bdf, but now it's down to the should-have-foreseen-it problem that the error message isn't what the expected-output file expects. Let's see if we can get stable results by printing just the SQLSTATE. I believe we'll reliably see ERRCODE_CONNECTION_FAILURE, since pgfdw_report_error() will report that for any libpq-originated error. There may be a better way to do this, but I'd like to get the buildfarm back to green before we discuss further improvements. Discussion: https://postgr.es/m/E1kPc9v-0005L4-2l@gemulon.postgresql.org Discussion: https://postgr.es/m/2621622.1602184554@sss.pgh.pa.us	5 years ago
Fujii Masao	32a9c0bdf4	postgres_fdw: reestablish new connection if cached one is detected as broken. ... In postgres_fdw, once remote connections are established, they are cached and re-used for subsequent queries and transactions. There can be some cases where those cached connections are unavaiable, for example, by the restart of remote server. In these cases, previously an error was reported and the query accessing to remote server failed if new remote transaction failed to start because the cached connection was broken. This commit improves postgres_fdw so that new connection is remade if broken connection is detected when starting new remote transaction. This is useful to avoid unnecessary failure of queries when connection is broken but can be reestablished. Author: Bharath Rupireddy, tweaked a bit by Fujii Masao Reviewed-by: Ashutosh Bapat, Tatsuhito Kasahara, Fujii Masao Discussion: https://postgr.es/m/CALj2ACUAi23vf1WiHNar_LksM9EDOWXcbHCo-fD4Mbr1d=78YQ@mail.gmail.com	5 years ago
Tom Lane	76f412ab31	Remove factorial operators, leaving only the factorial() function. ... The "!" operator is our only built-in postfix operator. Remove it, on the way to removal of grammar support for postfix operators. There is also a "!!" prefix operator, but since it's been marked deprecated for most of its existence, we might as well remove it too. Also zap the SQL alias function numeric_fac(), which seems to have equally little reason to live. Mark Dilger, based on work by myself and Robert Haas; review by John Naylor Discussion: https://postgr.es/m/38ca86db-42ab-9b48-2902-337a0d6b8311@2ndquadrant.com	5 years ago
Michael Paquier	a6642b3ae0	Add support for partitioned tables and indexes in REINDEX ... Until now, REINDEX was not able to work with partitioned tables and indexes, forcing users to reindex partitions one by one. This extends REINDEX INDEX and REINDEX TABLE so as they can accept a partitioned index and table in input, respectively, to reindex all the partitions assigned to them with physical storage (foreign tables, partitioned tables and indexes are then discarded). This shares some logic with schema and database REINDEX as each partition gets processed in its own transaction after building a list of relations to work on. This choice has the advantage to minimize the number of invalid indexes to one partition with REINDEX CONCURRENTLY in the event a cancellation or failure in-flight, as the only indexes handled at once in a single REINDEX CONCURRENTLY loop are the ones from the partition being working on. Isolation tests are added to emulate some cases I bumped into while developing this feature, particularly with the concurrent drop of a leaf partition reindexed. However, this is rather limited as LOCK would cause REINDEX to block in the first transaction building the list of partitions. Per its multi-transaction nature, this new flavor cannot run in a transaction block, similarly to REINDEX SCHEMA, SYSTEM and DATABASE. Author: Justin Pryzby, Michael Paquier Reviewed-by: Anastasia Lubennikova Discussion: https://postgr.es/m/db12e897-73ff-467e-94cb-4af03705435f.adger.lj@alibaba-inc.com	5 years ago
Jeff Davis	0babd10980	Revert "Use CP_SMALL_TLIST for hash aggregate" ... This reverts commit 4cad2534da due to a performance regression. It will be replaced by a new approach in an upcoming commit. Reported-by: Andres Freund Discussion: https://postgr.es/m/20200614181418.mx4bvljmfkkhoqzl@alap3.anarazel.de Backpatch-through: 13	5 years ago
Tomas Vondra	4cad2534da	Use CP_SMALL_TLIST for hash aggregate ... Commit 1f39bce021 added disk-based hash aggregation, which may spill incoming tuples to disk. It however did not request projection to make the tuples as narrow as possible, which may mean having to spill much more data than necessary (increasing I/O, pushing other stuff from page cache, etc.). This adds CP_SMALL_TLIST in places that may use hash aggregation - we do that only for AGG_HASHED. It's unnecessary for AGG_SORTED, because that either uses explicit Sort (which already does projection) or pre-sorted input (which does not need spilling to disk). Author: Tomas Vondra Reviewed-by: Jeff Davis Discussion: https://postgr.es/m/20200519151202.u2p2gpiawoaznsv2%40development	5 years ago
Michael Paquier	401aad6704	Rename connection parameters to control min/max SSL protocol version in libpq ... The libpq parameters ssl{max|min}protocolversion are renamed to use underscores, to become ssl_{max|min}_protocol_version. The related environment variables still use the names introduced in commit ff8ca5f that added the feature. Per complaint from Peter Eisentraut (this was also mentioned by me in the original patch review but the issue got discarded). Author: Daniel Gustafsson Reviewed-by: Peter Eisentraut, Michael Paquier Discussion: https://postgr.es/m/b319e449-318d-e691-4997-1327e166fcc4@2ndquadrant.com	5 years ago
Michael Paquier	ff8ca5fadd	Add connection parameters to control SSL protocol min/max in libpq ... These two new parameters, named sslminprotocolversion and sslmaxprotocolversion, allow to respectively control the minimum and the maximum version of the SSL protocol used for the SSL connection attempt. The default setting is to allow any version for both the minimum and the maximum bounds, causing libpq to rely on the bounds set by the backend when negotiating the protocol to use for an SSL connection. The bounds are checked when the values are set at the earliest stage possible as this makes the checks independent of any SSL implementation. Author: Daniel Gustafsson Reviewed-by: Michael Paquier, Cary Huang Discussion: https://postgr.es/m/4F246AE3-A7AE-471E-BD3D-C799D3748E03@yesql.se	6 years ago
Tom Lane	215824f918	In postgres_fdw, don't try to ship MULTIEXPR updates to remote server. ... In a statement like "UPDATE remote_tab SET (x,y) = (SELECT ...)", we'd conclude that the statement could be directly executed remotely, because the sub-SELECT is in a resjunk tlist item that's not examined for shippability. Currently that ends up crashing if the sub-SELECT contains any remote Vars. Prevent the crash by deeming MULTIEXEC Params to be unshippable. This is a bit of a brute-force solution, since if the sub-SELECT *doesn't* contain any remote Vars, the current execution technology would work; but that's not a terribly common use-case for this syntax, I think. In any case, we generally don't try to ship sub-SELECTs, so it won't surprise anybody that this doesn't end up as a remote direct update. I'd be inclined to see if that general limitation can be fixed before worrying about this case further. Per report from Lukáš Sobotka. Back-patch to 9.6. 9.5 had MULTIEXPR, but we didn't try to perform remote direct updates then, so the case didn't arise anyway. Discussion: https://postgr.es/m/CAJif3k+iA_ekBB5Zw2hDBaE1wtiQa4LH4_JUXrrMGwTrH0J01Q@mail.gmail.com	6 years ago
Andrew Dunstan	cebf9d6e6e	Only superuser can set sslcert/sslkey in postgres_fdw user mappings ... Othrwise there is a security risk. Discussion: https://postgr.es/m/20200109103014.GA4192@msg.df7cb.de	6 years ago
Andrew Dunstan	f5fd995a1a	Allow 'sslkey' and 'sslcert' in postgres_fdw user mappings ... This allows different users to authenticate with different certificates. Author: Craig Ringer	6 years ago
Tom Lane	0af0504da9	Adjust test case added by commit 6136e94dc. ... Per project policy, transient roles created by regression test cases should be named "regress_something", to reduce the risks of running such cases against installed servers. And no such role should ever be left behind after running a test. Discussion: https://postgr.es/m/11297.1576868677@sss.pgh.pa.us	6 years ago
Tom Lane	e60b480d39	libpq should expose GSS-related parameters even when not implemented. ... We realized years ago that it's better for libpq to accept all connection parameters syntactically, even if some are ignored or restricted due to lack of the feature in a particular build. However, that lesson from the SSL support was for some reason never applied to the GSSAPI support. This is causing various buildfarm members to have problems with a test case added by commit 6136e94dc, and it's just a bad idea from a user-experience standpoint anyway, so fix it. While at it, fix some places where parameter-related infrastructure was added with the aid of a dartboard, or perhaps with the aid of the anti-pattern "add new stuff at the end". It should be safe to rearrange the contents of struct pg_conn even in released branches, since that's private to libpq (and we'd have to move some fields in some builds to fix this, anyway). Back-patch to all supported branches. Discussion: https://postgr.es/m/11297.1576868677@sss.pgh.pa.us	6 years ago
Andrew Dunstan	6136e94dcb	Superuser can permit passwordless connections on postgres_fdw ... Currently postgres_fdw doesn't permit a non-superuser to connect to a foreign server without specifying a password, or to use an authentication mechanism that doesn't use the password. This is to avoid using the settings and identity of the user running Postgres. However, this doesn't make sense for all authentication methods. We therefore allow a superuser to set "password_required 'false'" for user mappings for the postgres_fdw. The superuser must ensure that the foreign server won't try to rely solely on the server identity (e.g. trust, peer, ident) or use an authentication mechanism that relies on the password settings (e.g. md5, scram-sha-256). This feature is a prelude to better support for sslcert and sslkey settings in user mappings. Author: Craig Ringer. Discussion: https://postgr.es/m/075135da-545c-f958-fed0-5dcb462d6dae@2ndQuadrant.com	6 years ago
Tom Lane	6ef77cf46e	Further adjust EXPLAIN's choices of table alias names. ... This patch causes EXPLAIN to always assign a separate table alias to the parent RTE of an append relation (inheritance set); before, such RTEs were ignored if not actually scanned by the plan. Since the child RTEs now always have that same alias to start with (cf. commit 55a1954da), the net effect is that the parent RTE usually gets the alias used or implied by the query text, and the children all get that alias with "_N" appended. (The exception to "usually" is if there are duplicate aliases in different subtrees of the original query; then some of those original RTEs will also have "_N" appended.) This results in more uniform output for partitioned-table plans than we had before: the partitioned table itself gets the original alias, and all child tables have aliases with "_N", rather than the previous behavior where one of the children would get an alias without "_N". The reason for giving the parent RTE an alias, even if it isn't scanned by the plan, is that we now use the parent's alias to qualify Vars that refer to an appendrel output column and appear above the Append or MergeAppend that computes the appendrel. But below the append, Vars refer to some one of the child relations, and are displayed that way. This seems clearer than the old behavior where a Var that could carry values from any child relation was displayed as if it referred to only one of them. While at it, change ruleutils.c so that the code paths used by EXPLAIN deal in Plan trees not PlanState trees. This effectively reverts a decision made in commit 1cc29fe7c, which seemed like a good idea at the time to make ruleutils.c consistent with explain.c. However, it's problematic because we'd really like to allow executor startup pruning to remove all the children of an append node when possible, leaving no child PlanState to resolve Vars against. (That's not done here, but will be in the next patch.) This requires different handling of subplans and initplans than before, but is otherwise a pretty straightforward change. Discussion: https://postgr.es/m/001001d4f44b$2a2cca50$7e865ef0$@lab.ntt.co.jp	6 years ago
Etsuro Fujita	5a20b0219e	Fix handling of multiple AFTER ROW triggers on a foreign table. ... AfterTriggerExecute() retrieves a fresh tuple or pair of tuples from a tuplestore and then stores the tuple(s) in the passed-in slot(s) if AFTER_TRIGGER_FDW_FETCH, while it uses the most-recently-retrieved tuple(s) stored in the slot(s) if AFTER_TRIGGER_FDW_REUSE. This was done correctly before 12, but commit ff11e7f4b broke it by mistakenly clearing the tuple(s) stored in the slot(s) in that function, leading to an assertion failure as reported in bug #16139 from Alexander Lakhin. Also, fix some other issues with the aforementioned commit in passing: * For tg_newslot, which is a slot added to the TriggerData struct by the commit to store new updated tuples, it didn't ensure the slot was NULL if there was no such tuple. * The commit failed to update the documentation about the trigger interface. Author: Etsuro Fujita Backpatch-through: 12 Discussion: https://postgr.es/m/16139-94f9ccf0db6119ec%40postgresql.org	6 years ago
Tom Lane	bf39b3af6a	Further sync postgres_fdw's "Relations" output with the rest of EXPLAIN. ... EXPLAIN generally only adds schema qualifications to table names when VERBOSE is specified. In postgres_fdw's "Relations" output, table names were always so qualified, but that was an implementation restriction: in the original coding, we didn't have access to the verbose flag at the time the string was generated. After the code rearrangement of commit 4526951d5, we do have that info available at the right time, so make this output follow the normal rule. Discussion: https://postgr.es/m/12424.1575168015@sss.pgh.pa.us	6 years ago