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* Fix BRIN free space computationsAlvaro Herrera2015-10-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | A bug in the original free space computation made it possible to return a page which wasn't actually able to fit the item. Since the insertion code isn't prepared to deal with PageAddItem failing, a PANIC resulted ("failed to add BRIN tuple [to new page]"). Add a macro to encapsulate the correct computation, and use it in brin_getinsertbuffer's callers before calling that routine, to raise an early error. I became aware of the possiblity of a problem in this area while working on ccc4c074994d734. There's no archived discussion about it, but it's easy to reproduce a problem in the unpatched code with something like CREATE TABLE t (a text); CREATE INDEX ti ON t USING brin (a) WITH (pages_per_range=1); for length in `seq 8000 8196` do psql -f - <<EOF TRUNCATE TABLE t; INSERT INTO t VALUES ('z'), (repeat('a', $length)); EOF done Backpatch to 9.5, where BRIN was introduced.
* Cleanup commit timestamp module activaction, againAlvaro Herrera2015-10-27
| | | | | | | | | | | | | Further tweak commit_ts.c so that on a standby the state is completely consistent with what that in the master, rather than behaving differently in the cases that the settings differ. Now in standby and master the module should always be active or inactive in lockstep. Author: Petr Jelínek, with some further tweaks by Álvaro Herrera. Backpatch to 9.5, where commit timestamps were introduced. Discussion: http://www.postgresql.org/message-id/5622BF9D.2010409@2ndquadrant.com
* Measure string lengths only onceAlvaro Herrera2015-10-27
| | | | | | | | | | | | | | | | | | | | Bernd Helmle complained that CreateReplicationSlot() was assigning the same value to the same variable twice, so we could remove one of them. Code inspection reveals that we can actually remove both assignments: according to the author the assignment was there for beauty of the strlen line only, and another possible fix to that is to put the strlen in its own line, so do that. To be consistent within the file, refactor all duplicated strlen() calls, which is what we do elsewhere in the backend anyway. In basebackup.c, snprintf already returns the right length; no need for strlen afterwards. Backpatch to 9.4, where replication slots were introduced, to keep code identical. Some of this is older, but the patch doesn't apply cleanly and it's only of cosmetic value anyway. Discussion: http://www.postgresql.org/message-id/BE2FD71DEA35A2287EA5F018@eje.credativ.lan
* shm_mq: Repair breakage from previous commit.Robert Haas2015-10-22
| | | | | | If the counterparty writes some data into the queue and then detaches, it's wrong to return SHM_MQ_DETACHED right away. If we do that, we fail to read whatever was written.
* Add two missing cases to ATWrongRelkindError.Robert Haas2015-10-22
| | | | | | | This way, we produce a better error message if someone tries to do something like ALTER INDEX .. ALTER COLUMN .. SET STORAGE. Amit Langote
* shm_mq: Fix failure to notice a dead counterparty when nowait is used.Robert Haas2015-10-22
| | | | | | | | | | | | The shm_mq mechanism was intended to optionally notice when the process on the other end of the queue fails to attach to the queue. It does this by allowing the user to pass a BackgroundWorkerHandle; if the background worker in question is launched and dies without attaching to the queue, then we know it never will. This logic works OK in blocking mode, but when called with nowait = true we fail to notice that this has happened due to an asymmetry in the logic. Repair. Reported off-list by Rushabh Lathia. Patch by me.
* Fix incorrect translation of minus-infinity datetimes for json/jsonb.Tom Lane2015-10-20
| | | | | | | | | | | | | Commit bda76c1c8cfb1d11751ba6be88f0242850481733 caused both plus and minus infinity to be rendered as "infinity", which is not only wrong but inconsistent with the pre-9.4 behavior of to_json(). Fix that by duplicating the coding in date_out/timestamp_out/timestamptz_out more closely. Per bug #13687 from Stepan Perlov. Back-patch to 9.4, like the previous commit. In passing, also re-pgindent json.c, since it had gotten a bit messed up by recent patches (and I was already annoyed by indentation-related problems in back-patching this fix ...)
* Put back ssl_renegotiation_limit parameter, but only allow 0.Robert Haas2015-10-20
| | | | | | | | | | | | Per a report from Shay Rojansky, Npgsql sends ssl_renegotiation_limit=0 in the startup packet because it does not support renegotiation; other clients which have not attempted to support renegotiation might well behave similarly. The recent removal of this parameter forces them to break compatibility with either current PostgreSQL versions, or previous ones. Per discussion, the best solution is to accept the parameter but only allow a value of 0. Shay Rojansky, edited a little by me.
* Fix incorrect handling of lookahead constraints in pg_regprefix().Tom Lane2015-10-19
| | | | | | | | | | | | | | | | | | | pg_regprefix was doing nothing with lookahead constraints, which would be fine if it were the right kind of nothing, but it isn't: we have to terminate our search for a fixed prefix, not just pretend the LACON arc isn't there. Otherwise, if the current state has both a LACON outarc and a single plain-color outarc, we'd falsely conclude that the color represents an addition to the fixed prefix, and generate an extracted index condition that restricts the indexscan too much. (See added regression test case.) Terminating the search is conservative: we could traverse the LACON arc (thus assuming that the constraint can be satisfied at runtime) and then examine the outarcs of the linked-to state. But that would be a lot more work than it seems worth, because writing a LACON followed by a single plain character is a pretty silly thing to do. This makes a difference only in rather contrived cases, but it's a bug, so back-patch to all supported branches.
* Miscellaneous cleanup of regular-expression compiler.Tom Lane2015-10-16
| | | | | | | | | | | | | | | | | Revert our previous addition of "all" flags to copyins() and copyouts(); they're no longer needed, and were never anything but an unsightly hack. Improve a couple of infelicities in the REG_DEBUG code for dumping the NFA data structure, including adding code to count the total number of states and arcs. Add a couple of missed error checks. Add some more documentation in the README file, and some regression tests illustrating cases that exceeded the state-count limit and/or took unreasonable amounts of time before this set of patches. Back-patch to all supported branches.
* Improve memory-usage accounting in regular-expression compiler.Tom Lane2015-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This code previously counted the number of NFA states it created, and complained if a limit was exceeded, so as to prevent bizarre regex patterns from consuming unreasonable time or memory. That's fine as far as it went, but the code paid no attention to how many arcs linked those states. Since regexes can be contrived that have O(N) states but will need O(N^2) arcs after fixempties() processing, it was still possible to blow out memory, and take a long time doing it too. To fix, modify the bookkeeping to count space used by both states and arcs. I did not bother with including the "color map" in the accounting; it can only grow to a few megabytes, which is not a lot in comparison to what we're allowing for states+arcs (about 150MB on 64-bit machines or half that on 32-bit machines). Looking at some of the larger real-world regexes captured in the Tcl regression test suite suggests that the most that is likely to be needed for regexes found in the wild is under 10MB, so I believe that the current limit has enough headroom to make it okay to keep it as a hard-wired limit. In connection with this, redefine REG_ETOOBIG as meaning "regular expression is too complex"; the previous wording of "nfa has too many states" was already somewhat inapropos because of the error code's use for stack depth overrun, and it was not very user-friendly either. Back-patch to all supported branches.
* Improve performance of pullback/pushfwd in regular-expression compiler.Tom Lane2015-10-16
| | | | | | | | | | | | | | | | | | | The previous coding would create a new intermediate state every time it wanted to interchange the ordering of two constraint arcs. Certain regex features such as \Y can generate large numbers of parallel constraint arcs, and if we needed to reorder the results of that, we created unreasonable numbers of intermediate states. To improve matters, keep a list of already-created intermediate states associated with the state currently being considered by the outer loop; we can re-use such states to place all the new arcs leading to the same destination or source. I also took the trouble to redefine push() and pull() to have a less risky API: they no longer delete any state or arc that the caller might possibly have a pointer to, except for the specifically-passed constraint arc. This reduces the risk of re-introducing the same type of error seen in the failed patch for CVE-2007-4772. Back-patch to all supported branches.
* Improve performance of fixempties() pass in regular-expression compiler.Tom Lane2015-10-16
| | | | | | | | | | | | | | | The previous coding took something like O(N^4) time to fully process a chain of N EMPTY arcs. We can't really do much better than O(N^2) because we have to insert about that many arcs, but we can do lots better than what's there now. The win comes partly from using mergeins() to amortize de-duplication of arcs across multiple source states, and partly from exploiting knowledge of the ordering of arcs for each state to avoid looking at arcs we don't need to consider during the scan. We do have to be a bit careful of the possible reordering of arcs introduced by the sort-merge coding of the previous commit, but that's not hard to deal with. Back-patch to all supported branches.
* Fix O(N^2) performance problems in regular-expression compiler.Tom Lane2015-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Change the singly-linked in-arc and out-arc lists to be doubly-linked, so that arc deletion is constant time rather than having worst-case time proportional to the number of other arcs on the connected states. Modify the bulk arc transfer operations copyins(), copyouts(), moveins(), moveouts() so that they use a sort-and-merge algorithm whenever there's more than a small number of arcs to be copied or moved. The previous method is O(N^2) in the number of arcs involved, because it performs duplicate checking independently for each copied arc. The new method may change the ordering of existing arcs for the destination state, but nothing really cares about that. Provide another bulk arc copying method mergeins(), which is unused as of this commit but is needed for the next one. It basically is like copyins(), but the source arcs might not all come from the same state. Replace the O(N^2) bubble-sort algorithm used in carcsort() with a qsort() call. These changes greatly improve the performance of regex compilation for large or complex regexes, at the cost of extra space for arc storage during compilation. The original tradeoff was probably fine when it was made, but now we care more about speed and less about memory consumption. Back-patch to all supported branches.
* Fix regular-expression compiler to handle loops of constraint arcs.Tom Lane2015-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's possible to construct regular expressions that contain loops of constraint arcs (that is, ^ $ AHEAD BEHIND or LACON arcs). There's no use in fully traversing such a loop at execution, since you'd just end up in the same NFA state without having consumed any input. Worse, such a loop leads to infinite looping in the pullback/pushfwd stage of compilation, because we keep pushing or pulling the same constraints around the loop in a vain attempt to move them to the pre or post state. Such looping was previously recognized in CVE-2007-4772; but the fix only handled the case of trivial single-state loops (that is, a constraint arc leading back to its source state) ... and not only that, it was incorrect even for that case, because it broke the admittedly-not-very-clearly-stated API contract of the pull() and push() subroutines. The first two regression test cases added by this commit exhibit patterns that result in assertion failures because of that (though there seem to be no ill effects in non-assert builds). The other new test cases exhibit multi-state constraint loops; in an unpatched build they will run until the NFA state-count limit is exceeded. To fix, remove the code added for CVE-2007-4772, and instead create a general-purpose constraint-loop-breaking phase of regex compilation that executes before we do pullback/pushfwd. Since we never need to traverse a constraint loop fully, we can just break the loop at any chosen spot, if we add clone states that can replicate any sequence of arc transitions that would've traversed just part of the loop. Also add some commentary clarifying why we have to have all these machinations in the first place. This class of problems has been known for some time --- we had a report from Marc Mamin about two years ago, for example, and there are related complaints in the Tcl bug tracker. I had discussed a fix of this kind off-list with Henry Spencer, but didn't get around to doing something about it until the issue was rediscovered by Greg Stark recently. Back-patch to all supported branches.
* Fix a problem with parallel workers being unable to restore role.Robert Haas2015-10-16
| | | | | | | | | check_role() tries to verify that the user has permission to become the requested role, but this is inappropriate in a parallel worker, which needs to exactly recreate the master's authorization settings. So skip the check in that case. This fixes a bug in commit 924bcf4f16d54c55310b28f77686608684734f42.
* Invalidate caches after cranking up a parallel worker transaction.Robert Haas2015-10-16
| | | | | | | | | | Starting a parallel worker transaction changes our notion of which XIDs are in-progress or committed, and our notion of the current command counter ID. Therefore, our view of these caches prior to starting this transaction may no longer valid. Defend against that by clearing them. This fixes a bug in commit 924bcf4f16d54c55310b28f77686608684734f42.
* Tighten up application of parallel mode checks.Robert Haas2015-10-16
| | | | | | | | | | | | | | Commit 924bcf4f16d54c55310b28f77686608684734f42 failed to enforce parallel mode checks during the commit of a parallel worker, because we exited parallel mode prior to ending the transaction so that we could pop the active snapshot. Re-establish parallel mode during parallel worker commit. Without this, it's far too easy for unsafe actions during the pre-commit sequence to crash the server instead of hitting the error checks as intended. Just to be extra paranoid, adjust a couple of the sanity checks in xact.c to check not only IsInParallelMode() but also IsParallelWorker().
* Transfer current command counter ID to parallel workers.Robert Haas2015-10-16
| | | | | | | | Commit 924bcf4f16d54c55310b28f77686608684734f42 correctly forbade parallel workers to modify the command counter while in parallel mode, but it inexplicably neglected to actually transfer the current command counter from leader to workers. This can result in the workers seeing a different set of tuples from the leader, which is bad. Repair.
* Don't send protocol messages to a shm_mq that no longer exists.Robert Haas2015-10-16
| | | | | | | | | | | Commit 2bd9e412f92bc6a68f3e8bcb18e04955cc35001d introduced a mechanism for relaying protocol messages from a background worker to another backend via a shm_mq. However, there was no provision for shutting down the communication channel. Therefore, a protocol message sent late in the shutdown sequence, such as a DEBUG message resulting from cranking up log_min_messages, could crash the server. To fix, install an on_dsm_detach callback that disables sending messages to the shm_mq when the associated DSM is detached.
* Fix NULL handling in datum_to_jsonb().Tom Lane2015-10-15
| | | | | | | | | | | The function failed to adhere to its specification that the "tcategory" argument should not be examined when the input value is NULL. This resulted in a crash in some cases. Per bug #13680 from Boyko Yordanov. In passing, re-pgindent some recent changes in jsonb.c, and fix a rather ungrammatical comment. Diagnosis and patch by Michael Paquier, cosmetic changes by me
* Allow FDWs to push down quals without breaking EvalPlanQual rechecks.Robert Haas2015-10-15
| | | | | | | | | | | | | | | | | This fixes a long-standing bug which was discovered while investigating the interaction between the new join pushdown code and the EvalPlanQual machinery: if a ForeignScan appears on the inner side of a paramaterized nestloop, an EPQ recheck would re-return the original tuple even if it no longer satisfied the pushed-down quals due to changed parameter values. This fix adds a new member to ForeignScan and ForeignScanState and a new argument to make_foreignscan, and requires changes to FDWs which push down quals to populate that new argument with a list of quals they have chosen to push down. Therefore, I'm only back-patching to 9.5, even though the bug is not new in 9.5. Etsuro Fujita, reviewed by me and by Kyotaro Horiguchi.
* Fix bogus commentsAlvaro Herrera2015-10-15
| | | | Author: Amit Langote
* Improve INSERT .. ON CONFLICT error message.Robert Haas2015-10-13
| | | | Peter Geoghegan, reviewed by me.
* On Windows, ensure shared memory handle gets closed if not being used.Tom Lane2015-10-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Postmaster child processes that aren't supposed to be attached to shared memory were not bothering to close the shared memory mapping handle they inherit from the postmaster process. That's mostly harmless, since the handle vanishes anyway when the child process exits -- but the syslogger process, if used, doesn't get killed and restarted during recovery from a backend crash. That meant that Windows doesn't see the shared memory mapping as becoming free, so it doesn't delete it and the postmaster is unable to create a new one, resulting in failure to recover from crashes whenever logging_collector is turned on. Per report from Dmitry Vasilyev. It's a bit astonishing that we'd not figured this out long ago, since it's been broken from the very beginnings of out native Windows support; probably some previously-unexplained trouble reports trace to this. A secondary problem is that on Cygwin (perhaps only in older versions?), exec() may not detach from the shared memory segment after all, in which case these child processes did remain attached to shared memory, posing the risk of an unexpected shared memory clobber if they went off the rails somehow. That may be a long-gone bug, but we can deal with it now if it's still live, by detaching within the infrastructure introduced here to deal with closing the handle. Back-patch to all supported branches. Tom Lane and Amit Kapila
* Use JsonbIteratorToken consistently in automatic variable declarations.Noah Misch2015-10-12
| | | | | | Many functions stored JsonbIteratorToken values in variables of other integer types. Also, standardize order relative to other declarations. Expect compilers to generate the same code before and after this change.
* Handle append_rel_list in expand_security_qualStephen Frost2015-10-09
| | | | | | | | | | | | | | | | | During expand_security_quals, we take the security barrier quals on an RTE and create a subquery which evaluates the quals. During this, we have to replace any variables in the outer query which refer to the original RTE with references to the columns from the subquery. We need to also perform that replacement for any Vars in the append_rel_list. Only backpatching to 9.5 as we only go through this process in 9.4 for auto-updatable security barrier views, which UNION ALL queries aren't. Discovered by Haribabu Kommi Patch by Dean Rasheed
* Fix uninitialized-variable bug.Tom Lane2015-10-09
| | | | | | | | | | | | | | | For some reason, neither of the compilers I usually use noticed the uninitialized-variable problem I introduced in commit 7e2a18a9161fee7e. That's hardly a good enough excuse though. Committing with brown paper bag on head. In addition to putting the operations in the right order, move the declaration of "now" inside the loop; there's no need for it to be outside, and that does wake up older gcc enough to notice any similar future problem. Back-patch to 9.4; earlier versions lack the time-to-SIGKILL stanza so there's no bug.
* Perform an immediate shutdown if the postmaster.pid file is removed.Tom Lane2015-10-06
| | | | | | | | | | | | | | | | | | | | | | | | The postmaster now checks every minute or so (worst case, at most two minutes) that postmaster.pid is still there and still contains its own PID. If not, it performs an immediate shutdown, as though it had received SIGQUIT. The original goal behind this change was to ensure that failed buildfarm runs would get fully cleaned up, even if the test scripts had left a postmaster running, which is not an infrequent occurrence. When the buildfarm script removes a test postmaster's $PGDATA directory, its next check on postmaster.pid will fail and cause it to exit. Previously, manual intervention was often needed to get rid of such orphaned postmasters, since they'd block new test postmasters from obtaining the expected socket address. However, by checking postmaster.pid and not something else, we can provide additional robustness: manual removal of postmaster.pid is a frequent DBA mistake, and now we can at least limit the damage that will ensue if a new postmaster is started while the old one is still alive. Back-patch to all supported branches, since we won't get the desired improvement in buildfarm reliability otherwise.
* Translation updatesPeter Eisentraut2015-10-05
| | | | | Source-Git-URL: git://git.postgresql.org/git/pgtranslation/messages.git Source-Git-Hash: 23a52bc86edcd39c3c6b80ee1f7374759c8711f8
* Prevent stack overflow in query-type functions.Noah Misch2015-10-05
| | | | | | The tsquery, ltxtquery and query_int data types have a common ancestor. Having acquired check_stack_depth() calls independently, each was missing at least one call. Back-patch to 9.0 (all supported versions).
* Prevent stack overflow in container-type functions.Noah Misch2015-10-05
| | | | | | | | | | | | | | A range type can name another range type as its subtype, and a record type can bear a column of another record type. Consequently, functions like range_cmp() and record_recv() are recursive. Functions at risk include operator family members and referents of pg_type regproc columns. Treat as recursive any such function that looks up and calls the same-purpose function for a record column type or the range subtype. Back-patch to 9.0 (all supported versions). An array type's element type is never itself an array type, so array functions are unaffected. Recursion depth proportional to array dimensionality, found in array_dim_to_jsonb(), is fine thanks to MAXDIM.
* Prevent stack overflow in json-related functions.Noah Misch2015-10-05
| | | | | | | | | | | | | | Sufficiently-deep recursion heretofore elicited a SIGSEGV. If an application constructs PostgreSQL json or jsonb values from arbitrary user input, application users could have exploited this to terminate all active database connections. That applies to 9.3, where the json parser adopted recursive descent, and later versions. Only row_to_json() and array_to_json() were at risk in 9.2, both in a non-security capacity. Back-patch to 9.2, where the json type was introduced. Oskari Saarenmaa, reviewed by Michael Paquier. Security: CVE-2015-5289
* Apply SELECT policies in INSERT/UPDATE+RETURNINGStephen Frost2015-10-05
| | | | | | | | Similar to 7d8db3e, given that INSERT+RETURNING requires SELECT rights on the table, apply the SELECT policies as WCOs to the tuples being inserted. Apply the same logic to UPDATE+RETURNING. Back-patch to 9.5 where RLS was added.
* Do not write out WCOs in QueryStephen Frost2015-10-05
| | | | | | | | | | The WithCheckOptions list in Query are only populated during rewrite and do not need to be written out or read in as part of a Query structure. Further, move WithCheckOptions to the bottom and add comments to clarify that it is only populated during rewrite. Back-patch to 9.5 with a catversion bump, as we are still in alpha.
* Re-Align *_freeze_max_age reloption limits with corresponding GUC limits.Andres Freund2015-10-05
| | | | | | | | | | | | | | In 020235a5754 I lowered the autovacuum_*freeze_max_age minimums to allow for easier testing of wraparounds. I did not touch the corresponding per-table limits. While those don't matter for the purpose of wraparound, it seems more consistent to lower them as well. It's noteworthy that the previous reloption lower limit for autovacuum_multixact_freeze_max_age was too high by one magnitude, even before 020235a5754. Discussion: 26377.1443105453@sss.pgh.pa.us Backpatch: back to 9.0 (in parts), like the prior patch
* ALTER TABLE .. FORCE ROW LEVEL SECURITYStephen Frost2015-10-04
| | | | | | | | | | | | | | | | | To allow users to force RLS to always be applied, even for table owners, add ALTER TABLE .. FORCE ROW LEVEL SECURITY. row_security=off overrides FORCE ROW LEVEL SECURITY, to ensure pg_dump output is complete (by default). Also add SECURITY_NOFORCE_RLS context to avoid data corruption when ALTER TABLE .. FORCE ROW SECURITY is being used. The SECURITY_NOFORCE_RLS security context is used only during referential integrity checks and is only considered in check_enable_rls() after we have already checked that the current user is the owner of the relation (which should always be the case during referential integrity checks). Back-patch to 9.5 where RLS was added.
* Further twiddling of nodeHash.c hashtable sizing calculation.Tom Lane2015-10-04
| | | | | | | | | | | On reflection, the submitted patch didn't really work to prevent the request size from exceeding MaxAllocSize, because of the fact that we'd happily round nbuckets up to the next power of 2 after we'd limited it to max_pointers. The simplest way to enforce the limit correctly is to round max_pointers down to a power of 2 when it isn't one already. (Note that the constraint to INT_MAX / 2, if it were doing anything useful at all, is properly applied after that.)
* Fix some issues in new hashtable size calculations in nodeHash.c.Tom Lane2015-10-04
| | | | | | | | | | | | | | | | Limit the size of the hashtable pointer array to not more than MaxAllocSize, per reports from Kouhei Kaigai and others of "invalid memory alloc request size" failures. There was discussion of allowing the array to get larger than that by using the "huge" palloc API, but so far no proof that that is actually a good idea, and at this point in the 9.5 cycle major changes from old behavior don't seem like the way to go. Fix a rather serious secondary bug in the new code, which was that it didn't ensure nbuckets remained a power of 2 when recomputing it for the multiple-batch case. Clean up sloppy division of labor between ExecHashIncreaseNumBuckets and its sole call site.
* Disallow invalid path elements in jsonb_setAndrew Dunstan2015-10-04
| | | | | | | | | Null path elements and, where the object is an array, invalid integer elements now cause an error. Incorrect behaviour noted by Thom Brown, patch from Dmitry Dolgov. Backpatch to 9.5 where jsonb_set was introduced
* Group cluster_name and update_process_title settings togetherPeter Eisentraut2015-10-04
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* Make BYPASSRLS behave like superuser RLS bypass.Noah Misch2015-10-03
| | | | | | | | Specifically, make its effect independent from the row_security GUC, and make it affect permission checks pertinent to views the BYPASSRLS role owns. The row_security GUC thereby ceases to change successful-query behavior; it can only make a query fail with an error. Back-patch to 9.5, where BYPASSRLS was introduced.
* Improve errhint() about replication slot naming restrictions.Andres Freund2015-10-03
| | | | | | | | | | The existing hint talked about "may only contain letters", but the actual requirement is more strict: only lower case letters are allowed. Reported-By: Rushabh Lathia Author: Rushabh Lathia Discussion: AGPqQf2x50qcwbYOBKzb4x75sO_V3g81ZsA8+Ji9iN5t_khFhQ@mail.gmail.com Backpatch: 9.4-, where replication slots were added
* Fix several bugs related to ON CONFLICT's EXCLUDED pseudo relation.Andres Freund2015-10-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Four related issues: 1) attnos/varnos/resnos for EXCLUDED were out of sync when a column after one dropped in the underlying relation was referenced. 2) References to whole-row variables (i.e. EXCLUDED.*) lead to errors. 3) It was possible to reference system columns in the EXCLUDED pseudo relations, even though they would not have valid contents. 4) References to EXCLUDED were rewritten by the RLS machinery, as EXCLUDED was treated as if it were the underlying relation. To fix the first two issues, generate the excluded targetlist with dropped columns in mind and add an entry for whole row variables. Instead of unconditionally adding a wholerow entry we could pull up the expression if needed, but doing it unconditionally seems simpler. The wholerow entry is only really needed for ruleutils/EXPLAIN support anyway. The remaining two issues are addressed by changing the EXCLUDED RTE to have relkind = composite. That fits with EXCLUDED not actually being a real relation, and allows to treat it differently in the relevant places. scanRTEForColumn now skips looking up system columns when the RTE has a composite relkind; fireRIRrules() already had a corresponding check, thereby preventing RLS expansion on EXCLUDED. Also add tests for these issues, and improve a few comments around excluded handling in setrefs.c. Reported-By: Peter Geoghegan, Geoff Winkless Author: Andres Freund, Amit Langote, Peter Geoghegan Discussion: CAEzk6fdzJ3xYQZGbcuYM2rBd2BuDkUksmK=mY9UYYDugg_GgZg@mail.gmail.com, CAM3SWZS+CauzbiCEcg-GdE6K6ycHE_Bz6Ksszy8AoixcMHOmsA@mail.gmail.com Backpatch: 9.5, where ON CONFLICT was introduced
* Add recursion depth protection to LIKE matching.Tom Lane2015-10-02
| | | | | Since MatchText() recurses, it could in principle be driven to stack overflow, although quite a long pattern would be needed.
* Add recursion depth protections to regular expression matching.Tom Lane2015-10-02
| | | | | | | | | | | | | | | Some of the functions in regex compilation and execution recurse, and therefore could in principle be driven to stack overflow. The Tcl crew has seen this happen in practice in duptraverse(), though their fix was to put in a hard-wired limit on the number of recursive levels, which is not too appetizing --- fortunately, we have enough infrastructure to check the actually available stack. Greg Stark has also seen it in other places while fuzz testing on a machine with limited stack space. Let's put guards in to prevent crashes in all these places. Since the regex code would leak memory if we simply threw elog(ERROR), we have to introduce an API that checks for stack depth without throwing such an error. Fortunately that's not difficult.
* Fix potential infinite loop in regular expression execution.Tom Lane2015-10-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In cfindloop(), if the initial call to shortest() reports that a zero-length match is possible at the current search start point, but then it is unable to construct any actual match to that, it'll just loop around with the same start point, and thus make no progress. We need to force the start point to be advanced. This is safe because the loop over "begin" points has already tried and failed to match starting at "close", so there is surely no need to try that again. This bug was introduced in commit e2bd904955e2221eddf01110b1f25002de2aaa83, wherein we allowed continued searching after we'd run out of match possibilities, but evidently failed to think hard enough about exactly where we needed to search next. Because of the way this code works, such a match failure is only possible in the presence of backrefs --- otherwise, shortest()'s judgment that a match is possible should always be correct. That probably explains how come the bug has escaped detection for several years. The actual fix is a one-liner, but I took the trouble to add/improve some comments related to the loop logic. After fixing that, the submitted test case "()*\1" didn't loop anymore. But it reported failure, though it seems like it ought to match a zero-length string; both Tcl and Perl think it does. That seems to be from overenthusiastic optimization on my part when I rewrote the iteration match logic in commit 173e29aa5deefd9e71c183583ba37805c8102a72: we can't just "declare victory" for a zero-length match without bothering to set match data for capturing parens inside the iterator node. Per fuzz testing by Greg Stark. The first part of this is a bug in all supported branches, and the second part is a bug since 9.2 where the iteration rewrite happened.
* Add some more query-cancel checks to regular expression matching.Tom Lane2015-10-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 9662143f0c35d64d7042fbeaf879df8f0b54be32 added infrastructure to allow regular-expression operations to be terminated early in the event of SIGINT etc. However, fuzz testing by Greg Stark disclosed that there are still cases where regex compilation could run for a long time without noticing a cancel request. Specifically, the fixempties() phase never adds new states, only new arcs, so it doesn't hit the cancel check I'd put in newstate(). Add one to newarc() as well to cover that. Some experimentation of my own found that regex execution could also run for a long time despite a pending cancel. We'd put a high-level cancel check into cdissect(), but there was none inside the core text-matching routines longest() and shortest(). Ordinarily those inner loops are very very fast ... but in the presence of lookahead constraints, not so much. As a compromise, stick a cancel check into the stateset cache-miss function, which is enough to guarantee a cancel check at least once per lookahead constraint test. Making this work required more attention to error handling throughout the regex executor. Henry Spencer had apparently originally intended longest() and shortest() to be incapable of incurring errors while running, so neither they nor their subroutines had well-defined error reporting behaviors. However, that was already broken by the lookahead constraint feature, since lacon() can surely suffer an out-of-memory failure --- which, in the code as it stood, might never be reported to the user at all, but just silently be treated as a non-match of the lookahead constraint. Normalize all that by inserting explicit error tests as needed. I took the opportunity to add some more comments to the code, too. Back-patch to all supported branches, like the previous patch.
* Don't disable commit_ts in standby if enabled locallyAlvaro Herrera2015-10-02
| | | | Bug noticed by Fujii Masao
* Fix message punctuation according to style guidePeter Eisentraut2015-10-01
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