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* Ensure mark_dummy_rel doesn't create dangling pointers in RelOptInfos.Tom Lane2011-04-13
| | | | | | | | | | | | | | | When we are doing GEQO join planning, the current memory context is a short-lived context that will be reset at the end of geqo_eval(). However, the RelOptInfos for base relations are set up before that and then re-used across many GEQO cycles. Hence, any code that modifies a baserel during join planning has to be careful not to put pointers to the short-lived context into the baserel struct. mark_dummy_rel got this wrong, leading to easy-to-reproduce-once-you-know-how crashes in 8.4, as reported off-list by Leo Carson of SDSC. Some improvements made in 9.0 make it difficult to demonstrate the crash in 9.0 or HEAD; but there's no doubt that there's still a risk factor here, so patch all branches that have the function. (Note: 8.3 has a similar function, but it's only applied to joinrels and thus is not a hazard.)
* On IA64 architecture, we check the depth of the register stack in additionHeikki Linnakangas2011-04-13
| | | | | to the regular stack. The code to do that is platform and compiler specific, add support for the HP-UX native compiler.
* Be more wary of missing statistics in eqjoinsel_semi().Tom Lane2011-04-12
| | | | | | | | In particular, if we don't have real ndistinct estimates for both sides, fall back to assuming that half of the left-hand rows have join partners. This is what was done in 8.2 and 8.3 (cf nulltestsel() in those versions). It's pretty stupid but it won't lead us to think that an antijoin produces no rows out, as seen in recent example from Uwe Schroeder.
* Modernize dlopen interface code for FreeBSD and OpenBSD.Tom Lane2011-04-07
| | | | | | | | | | Remove the hard-wired assumption that __mips__ (and only __mips__) lacks dlopen in FreeBSD and OpenBSD. This assumption is outdated at least for OpenBSD, as per report from an anonymous 9.1 tester. We can perfectly well use HAVE_DLOPEN instead to decide which code to use. Some other cosmetic adjustments to make freebsd.c, netbsd.c, and openbsd.c exactly alike.
* Fix plpgsql's issues with dropped columns in rowtypes in 8.4 branch.Tom Lane2011-04-07
| | | | | | | | | | | This is a back-patch of commit dcb2bda9b7042dbf43f876c94ebf35d951de10e9 of Aug 6 2009, which fixed assorted cases in which plpgsql would fail to cope with composite types that contain any dropped columns. Per discussion, this fix has been out in 9.0 for long enough to make it improbable that it creates any new bugs, so this is a low-risk fix. To make it even lower risk, I did not back-patch the changes in execQual.c, but just accepted the duplication of code between there and tupconvert.c. The added files tupconvert.h and tupconvert.c match their current states in HEAD.
* Prevent a rowtype from being included in itself.Tom Lane2011-03-28
| | | | | | | | | | | | | | | | Eventually we might be able to allow that, but it's not clear how many places need to be fixed to prevent infinite recursion when there's a direct or indirect inclusion of a rowtype in itself. One such place is CheckAttributeType(), which will recurse to stack overflow in cases such as those exhibited in bug #5950 from Alex Perepelica. If we were sure it was the only such place, we could easily modify the code added by this patch to stop the recursion without a complaint ... but it probably isn't the only such place. Hence, throw error until such time as someone is excited enough about this type of usage to put work into making it safe. Back-patch as far as 8.3. 8.2 doesn't have the recursive call in CheckAttributeType in the first place, so I see no need to add code there in the absence of clear evidence of a problem elsewhere.
* Avoid potential deadlock in InitCatCachePhase2().Tom Lane2011-03-22
| | | | | | | | | | | | | | | Opening a catcache's index could require reading from that cache's own catalog, which of course would acquire AccessShareLock on the catalog. So the original coding here risks locking index before heap, which could deadlock against another backend trying to get exclusive locks in the normal order. Because InitCatCachePhase2 is only called when a backend has to start up without a relcache init file, the deadlock was seldom seen in the field. (And by the same token, there's no need to worry about any performance disadvantage; so not much point in trying to distinguish exactly which catalogs have the risk.) Bug report, diagnosis, and patch by Nikhil Sontakke. Additional commentary by me. Back-patch to all supported branches.
* On further reflection, we'd better do the same in int.c.Tom Lane2011-03-11
| | | | | We previously heard of the same problem in int24div(), so there's not a good reason to suppose the problem is confined to cases involving int8.
* Put in some more safeguards against executing a division-by-zero.Tom Lane2011-03-11
| | | | | | | | Add dummy returns before every potential division-by-zero in int8.c, because apparently further "improvements" in gcc's optimizer have enabled it to break functions that weren't broken before. Aurelien Jarno, via Martin Pitt
* Don't throw a warning if vacuum sees PD_ALL_VISIBLE flag set on a page thatHeikki Linnakangas2011-03-08
| | | | | | | | | | | | | | | | | | | | contains newly-inserted tuples that according to our OldestXmin are not yet visible to everyone. The value returned by GetOldestXmin() is conservative, and it can move backwards on repeated calls, so if we see that contradiction between the PD_ALL_VISIBLE flag and status of tuples on the page, we have to assume it's because an earlier vacuum calculated a higher OldestXmin value, and all the tuples really are visible to everyone. We have received several reports of this bug, with the "PD_ALL_VISIBLE flag was incorrectly set in relation ..." warning appearing in logs. We were finally able to hunt it down with David Gould's help to run extra diagnostics in an environment where this happened frequently. Also reword the warning, per Robert Haas' suggestion, to not imply that the PD_ALL_VISIBLE flag is necessarily at fault, as it might also be a symptom of corruption on a tuple header. Backpatch to 8.4, where the PD_ALL_VISIBLE flag was introduced.
* Fix dangling-pointer problem in before-row update trigger processing.Tom Lane2011-02-21
| | | | | | | | | | | | | | | | | | | | | | ExecUpdate checked for whether ExecBRUpdateTriggers had returned a new tuple value by seeing if the returned tuple was pointer-equal to the old one. But the "old one" was in estate->es_junkFilter's result slot, which would be scribbled on if we had done an EvalPlanQual update in response to a concurrent update of the target tuple; therefore we were comparing a dangling pointer to a live one. Given the right set of circumstances we could get a false match, resulting in not forcing the tuple to be stored in the slot we thought it was stored in. In the case reported by Maxim Boguk in bug #5798, this led to "cannot extract system attribute from virtual tuple" failures when trying to do "RETURNING ctid". I believe there is a very-low-probability chance of more serious errors, such as generating incorrect index entries based on the original rather than the trigger-modified version of the row. In HEAD, change all of ExecBRInsertTriggers, ExecIRInsertTriggers, ExecBRUpdateTriggers, and ExecIRUpdateTriggers so that they continue to have similar APIs. In the back branches I just changed ExecBRUpdateTriggers, since there is no bug in the ExecBRInsertTriggers case.
* Fix tsmatchsel() to account properly for null rows.Tom Lane2011-02-17
| | | | | | | | | | | ts_typanalyze.c computes MCE statistics as fractions of the non-null rows, which seems fairly reasonable, and anyway changing it in released versions wouldn't be a good idea. But then ts_selfuncs.c has to account for that. Failure to do so results in overestimates in columns with a significant fraction of null documents. Back-patch to 8.4 where this stuff was introduced. Jesper Krogh
* Add CheckTableNotInUse calls in DROP TABLE and DROP INDEX.Tom Lane2011-02-15
| | | | | | | | | | | | | Recent releases had a check on rel->rd_refcnt in heap_drop_with_catalog, but failed to cover the possibility of pending trigger events at DROP time. (Before 8.4 we didn't even check the refcnt.) When the trigger events were eventually fired, you'd get "could not open relation with OID nnn" errors, as in recent report from strk. Better to throw a suitable error when the DROP is attempted. Also add a similar check in DROP INDEX. Back-patch to all supported branches.
* Fix wrong error reports in 'number of array dimensions exceeds theItagaki Takahiro2011-02-01
| | | | | | maximum allowed' messages, that have reported one-less dimensions. Alexey Klyukin
* Make reduce_outer_joins() smarter about semijoins.Tom Lane2011-01-30
| | | | | | | | | | | | | | reduce_outer_joins() mistakenly treated a semijoin like a left join for purposes of deciding whether not-null constraints created by the join's quals could be passed down into the join's left-hand side (possibly resulting in outer-join simplification there). Actually, semijoin works like inner join for this purpose, ie, we do not need to see any rows that can't possibly satisfy the quals. Hence, two-line fix to treat semi and inner joins alike. Per observation by Andres Freund about a performance gripe from Yazan Suleiman. Back-patch to 8.4, since this oversight has been there since the current handling of semijoins was implemented.
* Don't include <asm/ia64regs.h> unnecessarily.Tom Lane2011-01-27
| | | | | | | We only need that header when compiling with icc, since the gcc variant of ia64_get_bsp() uses in-line assembly code. Per report from Frank Brendel, the header doesn't exist on all IA64 platforms; so don't include it unless we need it.
* Translation updates for release 8.4.7Peter Eisentraut2011-01-27
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* Fix miscalculation of itemsafter in array_set_slice().Tom Lane2011-01-17
| | | | | | | | | | | If the slice to be assigned to was before the existing array lower bound (requiring at least one null element to spring into existence to fill the gap), the code miscalculated how many entries needed to be copied from the old array's null bitmap. This could result in trashing the array's data area (as seen in bug #5840 from Karsten Loesing), or worse. This has been broken since we first allowed the behavior of assigning to non-adjacent slices, in 8.2. Back-patch to all affected versions.
* Work around header misdefines in modern Windows SDK when _WIN32_WINNT is ↵Andrew Dunstan2011-01-04
| | | | less than 0x0501. Only required for versions 8.2, 8.3 and 8.4., as we defined _WIN32_WINNT as 0x0501 after that.
* Avoid unexpected conversion overflow in planner for distant date values.Tom Lane2010-12-28
| | | | | | | | | | | | | | The "date" type supports a wider range of dates than int64 timestamps do. However, there is pre-int64-timestamp code in the planner that assumes that all date values can be converted to timestamp with impunity. Fortunately, what we really need out of the conversion is always a double (float8) value; so even when the date is out of timestamp's range it's possible to produce a sane answer. All we need is a code path that doesn't try to force the result into int64. Per trouble report from David Rericha. Back-patch to all supported versions. Although this is surely a corner case, there's not much point in advertising a date range wider than timestamp's if we will choke on such values in unexpected places.
* Fix up handling of simple-form CASE with constant test expression.Tom Lane2010-12-19
| | | | | | | | | | | | | | | | | | | | | | | | | eval_const_expressions() can replace CaseTestExprs with constants when the surrounding CASE's test expression is a constant. This confuses ruleutils.c's heuristic for deparsing simple-form CASEs, leading to Assert failures or "unexpected CASE WHEN clause" errors. I had put in a hack solution for that years ago (see commit 514ce7a331c5bea8e55b106d624e55732a002295 of 2006-10-01), but bug #5794 from Peter Speck shows that that solution failed to cover all cases. Fortunately, there's a much better way, which came to me upon reflecting that Peter's "CASE TRUE WHEN" seemed pretty redundant: we can "simplify" the simple-form CASE to the general form of CASE, by simply omitting the constant test expression from the rebuilt CASE construct. This is intuitively valid because there is no need for the executor to evaluate the test expression at runtime; it will never be referenced, because any CaseTestExprs that would have referenced it are now replaced by constants. This won't save a whole lot of cycles, since evaluating a Const is pretty cheap, but a cycle saved is a cycle earned. In any case it beats kluging ruleutils.c still further. So this patch improves const-simplification and reverts the previous change in ruleutils.c. Back-patch to all supported branches. The bug exists in 8.1 too, but it's out of warranty.
* Fix erroneous parsing of tsquery input "... & !(subexpression) | ..."Tom Lane2010-12-19
| | | | | | | | | | | After parsing a parenthesized subexpression, we must pop all pending ANDs and NOTs off the stack, just like the case for a simple operand. Per bug #5793. Also fix clones of this routine in contrib/intarray and contrib/ltree, where input of types query_int and ltxtquery had the same problem. Back-patch to all supported versions.
* Remove optreset from src/port/ implementations of getopt and getopt_long.Tom Lane2010-12-16
| | | | | | | | | | We don't actually need optreset, because we can easily fix the code to ensure that it's cleanly restartable after having completed a scan over the argv array; which is the only case we need to restart in. Getting rid of it avoids a class of interactions with the system libraries and allows reversion of my change of yesterday in postmaster.c and postgres.c. Back-patch to 8.4. Before that the getopt code was a bit different anyway.
* Fix up getopt() reset management so it works on recent mingw.Tom Lane2010-12-15
| | | | | | | | | The mingw people don't appear to care about compatibility with non-GNU versions of getopt, so force use of our own copy of getopt on Windows. Also, ensure that we make use of optreset when using our own copy. Per report from Andrew Dunstan. Back-patch to all versions supported on Windows.
* Translation updates for release 8.4.6Peter Eisentraut2010-12-13
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* Fix efficiency problems in tuplestore_trim().Tom Lane2010-12-10
| | | | | | | | | | | | | | | | | | | | | | The original coding in tuplestore_trim() was only meant to work efficiently in cases where each trim call deleted most of the tuples in the store. Which, in fact, was the pattern of the original usage with a Material node supporting mark/restore operations underneath a MergeJoin. However, WindowAgg now uses tuplestores and it has considerably less friendly trimming behavior. In particular it can attempt to trim one tuple at a time off a large tuplestore. tuplestore_trim() had O(N^2) runtime in this situation because of repeatedly shifting its tuple pointer array. Fix by avoiding shifting the array until a reasonably large number of tuples have been deleted. This can waste some pointer space, but we do still reclaim the tuples themselves, so the percentage wastage should be pretty small. Per Jie Li's report of slow percent_rank() evaluation. cume_dist() and ntile() would certainly be affected as well, along with any other window function that has a moving frame start and requires reading substantially ahead of the current row. Back-patch to 8.4, where window functions were introduced. There's no need to tweak it before that.
* Force default wal_sync_method to be fdatasync on Linux.Tom Lane2010-12-08
| | | | | | | | | | | | | | | | | | | | | | | Recent versions of the Linux system header files cause xlogdefs.h to believe that open_datasync should be the default sync method, whereas formerly fdatasync was the default on Linux. open_datasync is a bad choice, first because it doesn't actually outperform fdatasync (in fact the reverse), and second because we try to use O_DIRECT with it, causing failures on certain filesystems (e.g., ext4 with data=journal option). This part of the patch is largely per a proposal from Marti Raudsepp. More extensive changes are likely to follow in HEAD, but this is as much change as we want to back-patch. Also clean up confusing code and incorrect documentation surrounding the fsync_writethrough option. Those changes shouldn't result in any actual behavioral change, but I chose to back-patch them anyway to keep the branches looking similar in this area. In 9.0 and HEAD, also do some copy-editing on the WAL Reliability documentation section. Back-patch to all supported branches, since any of them might get used on modern Linux versions.
* Add a stack overflow check to copyObject().Tom Lane2010-12-06
| | | | | | | | | | | | | | | There are some code paths, such as SPI_execute(), where we invoke copyObject() on raw parse trees before doing parse analysis on them. Since the bison grammar is capable of building heavily nested parsetrees while itself using only minimal stack depth, this means that copyObject() can be the front-line function that hits stack overflow before anything else does. Accordingly, it had better have a check_stack_depth() call. I did a bit of performance testing and found that this slows down copyObject() by only a few percent, so the hit ought to be negligible in the context of complete processing of a query. Per off-list report from Toshihide Katayama. Back-patch to all supported branches.
* Prevent inlining a SQL function with multiple OUT parameters.Tom Lane2010-12-01
| | | | | | | | | | | | | There were corner cases in which the planner would attempt to inline such a function, which would result in a failure at runtime due to loss of information about exactly what the result record type is. Fix by disabling inlining when the function's recorded result type is RECORD. There might be some sub-cases where inlining could still be allowed, but this is a simple and backpatchable fix, so leave refinements for another day. Per bug #5777 from Nate Carson. Back-patch to all supported branches. 8.1 happens to avoid a core-dump here, but it still does the wrong thing.
* Fix leakage of cost_limit when multiple autovacuum workers are active.Tom Lane2010-11-19
| | | | | | | | | | | | | | | | When using default autovacuum_vac_cost_limit, autovac_balance_cost relied on VacuumCostLimit to contain the correct global value ... but after the first time through in a particular worker process, it didn't, because we'd trashed it in previous iterations. Depending on the state of other autovac workers, this could result in a steady reduction of the effective cost_limit setting as a particular worker processed more and more tables, causing it to go slower and slower. Spotted by Simon Poole (bug #5759). Fix by saving and restoring the GUC variables in the loop in do_autovacuum. In passing, improve a few comments. Back-patch to 8.3 ... the cost rebalancing code has been buggy since it was put in.
* The GiST scan algorithm uses LSNs to detect concurrent pages splits, butHeikki Linnakangas2010-11-16
| | | | | | | | | | | | | temporary indexes are not WAL-logged. We used a constant LSN for temporary indexes, on the assumption that we don't need to worry about concurrent page splits in temporary indexes because they're only visible to the current session. But that assumption is wrong, it's possible to insert rows and split pages in the same session, while a scan is in progress. For example, by opening a cursor and fetching some rows, and INSERTing new rows before fetching some more. Fix by generating fake increasing LSNs, used in place of real LSNs in temporary GiST indexes.
* Fix canAcceptConnections() bugs introduced by replication-related patches.Tom Lane2010-11-14
| | | | | | | | | | We must not return any "okay to proceed" result code without having checked for too many children, else we might fail later on when trying to add the new child to one of the per-child state arrays. It's not clear whether this oversight explains Stefan Kaltenbrunner's recent report, but it could certainly produce a similar symptom. Back-patch to 8.4; the logic was not broken before that.
* Add missing outfuncs.c support for struct InhRelation.Tom Lane2010-11-13
| | | | | | This is needed to support debug_print_parse, per report from Jon Nelson. Cursory testing via the regression tests suggests we aren't missing anything else.
* Fix old oversight in const-simplification of COALESCE() expressions.Tom Lane2010-11-12
| | | | | | | | | | | | | Once we have found a non-null constant argument, there is no need to examine additional arguments of the COALESCE. The previous coding got it right only if the constant was in the first argument position; otherwise it tried to simplify following arguments too, leading to unexpected behavior like this: regression=# select coalesce(f1, 42, 1/0) from int4_tbl; ERROR: division by zero It's a minor corner case, but a bug is a bug, so back-patch all the way.
* Fix bug introduced by the recent patch to check that the checkpoint redoHeikki Linnakangas2010-11-11
| | | | | | | location read from backup label file can be found: wasShutdown was set incorrectly when a backup label file was found. Jeff Davis, with a little tweaking by me.
* Fix line_construct_pm() for the case of "infinite" (DBL_MAX) slope.Tom Lane2010-11-10
| | | | | | | | | | | | | | This code was just plain wrong: what you got was not a line through the given point but a line almost indistinguishable from the Y-axis, although not truly vertical. The only caller that tries to use this function with m == DBL_MAX is dist_ps_internal for the case where the lseg is horizontal; it would end up producing the distance from the given point to the place where the lseg's line crosses the Y-axis. That function is used by other operators too, so there are several operators that could compute wrong distances from a line segment to something else. Per bug #5745 from jindiax. Back-patch to all supported branches.
* Repair memory leakage while ANALYZE-ing complex index expressions.Tom Lane2010-11-09
| | | | | | | | | | | | | | | | | The general design of memory management in Postgres is that intermediate results computed by an expression are not freed until the end of the tuple cycle. For expression indexes, ANALYZE has to re-evaluate each expression for each of its sample rows, and it wasn't bothering to free intermediate results until the end of processing of that index. This could lead to very substantial leakage if the intermediate results were large, as in a recent example from Jakub Ouhrabka. Fix by doing ResetExprContext for each sample row. This necessitates adding a datumCopy step to ensure that the final expression value isn't recycled too. Some quick testing suggests that this change adds at worst about 10% to the time needed to analyze a table with an expression index; which is annoying, but seems a tolerable price to pay to avoid unexpected out-of-memory problems. Back-patch to all supported branches.
* In rewriteheap.c (used by VACUUM FULL and CLUSTER), calculate the tupleHeikki Linnakangas2010-11-09
| | | | | | | | | | length stored in the line pointer the same way it's calculated in the normal heap_insert() codepath. As noted by Jeff Davis, the length stored by raw_heap_insert() included padding but the one stored by the normal codepath did not. While the mismatch seems to be harmless, inconsistency isn't good, and the normal codepath has received a lot more testing over the years. Backpatch to 8.3 where the heap rewrite code was introduced.
* Fix error handling in temp-file deletion with log_temp_files active.Tom Lane2010-11-08
| | | | | | | | | | | | | | | | | | | | The original coding in FileClose() reset the file-is-temp flag before unlinking the file, so that if control came back through due to an error, it wouldn't try to unlink the file twice. This was correct when written, but when the log_temp_files feature was added, the logging action was put in between those two steps. An error occurring during the logging action --- such as a query cancel --- would result in the unlink not getting done at all, as in recent report from Michael Glaesemann. To fix this, make sure that we do both the stat and the unlink before doing anything that could conceivably CHECK_FOR_INTERRUPTS. There is a judgment call here, which is which log message to emit first: if you can see only one, which should it be? I chose to log unlink failure at the risk of losing the log_temp_files log message --- after all, if the unlink does fail, the temp file is still there for you to see. Back-patch to all versions that have log_temp_files. The code was OK before that.
* Add support for detecting register-stack overrun on IA64.Tom Lane2010-11-06
| | | | | | | | Per recent investigation, the register stack can grow faster than the regular stack depending on compiler and choice of options. To avoid crashes we must check both stacks in check_stack_depth(). Back-patch to all supported versions.
* Fix adjust_semi_join to be more cautious about clauseless joins.Tom Lane2010-11-02
| | | | | | | It was reporting that these were fully indexed (hence cheap), when of course they're the exact opposite of that. I'm not certain if the case would arise in practice, since a clauseless semijoin is hard to produce in SQL, but if it did happen we'd make some dumb decisions.
* Ensure an index that uses a whole-row Var still depends on its table.Tom Lane2010-11-02
| | | | | | | | | | | | | | | | We failed to record any dependency on the underlying table for an index declared like "create index i on t (foo(t.*))". This would create trouble if the table were dropped without previously dropping the index. To fix, simplify some overly-cute code in index_create(), accepting the possibility that sometimes the whole-table dependency will be redundant. Also document this hazard in dependency.c. Per report from Kevin Grittner. In passing, prevent a core dump in pg_get_indexdef() if the index's table can't be found. I came across this while experimenting with Kevin's example. Not sure it's a real issue when the catalogs aren't corrupt, but might as well be cautious. Back-patch to all supported versions.
* Fix long-standing segfault when accept() or one of the calls made rightHeikki Linnakangas2010-10-27
| | | | | after accepting a connection fails, and the server is compiled with GSSAPI support. Report and patch by Alexander V. Chernikov, bug #5731.
* Before removing backup_label and irrevocably changing pg_control file, checkHeikki Linnakangas2010-10-26
| | | | | | | | that WAL file containing the checkpoint redo-location can be found. This avoids making the cluster irrecoverable if the redo location is in an earlie WAL file than the checkpoint record. Report, analysis and patch by Jeff Davis, with small changes by me.
* Fix assorted bugs in GIN's WAL replay logic.Tom Lane2010-10-11
| | | | | | | | | | | | | | The original coding was quite sloppy about handling the case where XLogReadBuffer fails (because the page has since been deleted). This would result in either "bad buffer id: 0" or an Assert failure during replay, if indeed the page were no longer there. In a couple of places it also neglected to check whether the change had already been applied, which would probably result in corrupted index contents. I believe that bug #5703 is an instance of the first problem. These issues could show up without replication, but only if you were unfortunate enough to crash between modification of a GIN index and the next checkpoint. Back-patch to 8.2, which is as far back as GIN has WAL support.
* Behave correctly if INSERT ... VALUES is decorated with additional clauses.Tom Lane2010-10-02
| | | | | | | | | | In versions 8.2 and up, the grammar allows attaching ORDER BY, LIMIT, FOR UPDATE, or WITH to VALUES, and hence to INSERT ... VALUES. But the special-case code for VALUES in transformInsertStmt() wasn't expecting any of those, and just ignored them, leading to unexpected results. Rather than complicate the special-case path, just ensure that the presence of any of those clauses makes us treat the query as if it had a general SELECT. Per report from Hitoshi Harada.
* Translation updates for 8.4.5Peter Eisentraut2010-09-30
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* Fix PlaceHolderVar mechanism's interaction with outer joins.Tom Lane2010-09-28
| | | | | | | | | | | | | | The point of a PlaceHolderVar is to allow a non-strict expression to be evaluated below an outer join, after which its value bubbles up like a Var and can be forced to NULL when the outer join's semantics require that. However, there was a serious design oversight in that, namely that we didn't ensure that there was actually a correct place in the plan tree to evaluate the placeholder :-(. It may be necessary to delay evaluation of an outer join to ensure that a placeholder that should be evaluated below the join can be evaluated there. Per recent bug report from Kirill Simonov. Back-patch to 8.4 where the PlaceHolderVar mechanism was introduced.
* Further fixes to the pg_get_expr() security fix in back branches.Tom Lane2010-09-25
| | | | | | | It now emerges that the JDBC driver expects to be able to use pg_get_expr() on an output of a sub-SELECT. So extend the check logic to be able to recurse into a sub-SELECT to see if the argument is ultimately coming from an appropriate column. Per report from Thomas Kellerer.
* Prevent show_session_authorization from crashing when session_authorizationTom Lane2010-09-23
| | | | | | | | | | | | | | | hasn't been set. The only known case where this can happen is when show_session_authorization is invoked in an autovacuum process, which is possible if an index function calls it, as for example in bug #5669 from Andrew Geery. We could perhaps try to return a sensible value, such as the name of the cluster-owning superuser; but that seems like much more trouble than the case is worth, and in any case it could create new possible failure modes. Simply returning an empty string seems like the most appropriate fix. Back-patch to all supported versions, even those before autovacuum, just in case there's another way to provoke this crash.