summaryrefslogtreecommitdiff
path: root/src/backend/replication/logical
AgeCommit message (Collapse)Author
2016-05-04Revert timeline following in replication slotsAlvaro Herrera
This reverts commits f07d18b6e94d, 82c83b337202, 3a3b309041b0, and 24c5f1a103ce. This feature has shown enough immaturity that it was deemed better to rip it out before rushing some more fixes at the last minute. There are discussions on larger changes in this area for the next release.
2016-05-02Fix code comments regarding logical decodingAlvaro Herrera
Back in 3b02ea4f0780 I added some comments in various places to explain how logical decoding and other things worked. Not all of the changes were welcome, because they were misleading or wrong. This changes them a little bit to make them more accurate. Some other comments are also changed to be more accurate. Also, fix a bunch of typos. Author: Álvaro Herrera, Craig Ringer Andres Freund reviewed some parts of this.
2016-04-26Emit invalidations to standby for transactions without xid.Andres Freund
So far, when a transaction with pending invalidations, but without an assigned xid, committed, we simply ignored those invalidation messages. That's problematic, because those are actually sent for a reason. Known symptoms of this include that existing sessions on a hot-standby replica sometimes fail to notice new concurrently built indexes and visibility map updates. The solution is to WAL log such invalidations in transactions without an xid. We considered to alternatively force-assign an xid, but that'd be problematic for vacuum, which might be run in systems with few xids. Important: This adds a new WAL record, but as the patch has to be back-patched, we can't bump the WAL page magic. This means that standbys have to be updated before primaries; otherwise "PANIC: standby_redo: unknown op code 32" errors can be encountered. XXX: Reported-By: Васильев Дмитрий, Masahiko Sawada Discussion: CAB-SwXY6oH=9twBkXJtgR4UC1NqT-vpYAtxCseME62ADwyK5OA@mail.gmail.com CAD21AoDpZ6Xjg=gFrGPnSn4oTRRcwK1EBrWCq9OqOHuAcMMC=w@mail.gmail.com
2016-04-14Fix trivial typo.Andres Freund
2016-04-14Fix core dump in ReorderBufferRestoreChange on alignment-picky platforms.Tom Lane
When re-reading an update involving both an old tuple and a new tuple from disk, reorderbuffer.c was careless about whether the new tuple is suitably aligned for direct access --- in general, it isn't. We'd missed seeing this in the buildfarm because the contrib/test_decoding tests exercise this code path only a few times, and by chance all of those cases have old tuples with length a multiple of 4, which is usually enough to make the access to the new tuple's t_len safe. For some still-not-entirely-clear reason, however, Debian's sparc build gets a bus error, as reported by Christoph Berg; perhaps it's assuming 8-byte alignment of the pointer? The lack of previous field reports is probably because you need all of these conditions to trigger a crash: an alignment-picky platform (not Intel), a transaction large enough to spill to disk, an update within that xact that changes a primary-key field and has an odd-length old tuple, and of course logical decoding tracing the transaction. Avoid the alignment assumption by using memcpy instead of fetching t_len directly, and add a test case that exposes the crash on picky platforms. Back-patch to 9.4 where the bug was introduced. Discussion: <20160413094117.GC21485@msg.credativ.de>
2016-04-14Adjust datatype of ReplicationState.acquired_by.Tom Lane
It was declared as "pid_t", which would be fine except that none of the places that printed it in error messages took any thought for the possibility that it's not equivalent to "int". This leads to warnings on some buildfarm members, and could possibly lead to actually wrong error messages on those platforms. There doesn't seem to be any very good reason not to just make it "int"; it's only ever assigned from MyProcPid, which is int. If we want to cope with PIDs that are wider than int, this is not the place to start. Also, fix the comment, which seems to perhaps be a leftover from a time when the field was only a bool? Per buildfarm. Back-patch to 9.5 which has same issue.
2016-04-13Add required database and origin filtering for logical messages.Andres Freund
Logical messages, added in 3fe3511d05, during decoding failed to filter messages emitted in other databases and messages emitted "under" a replication origin the output plugin isn't interested in. Add tests to verify that both types of filtering actually work. While touching message.sql remove hunk obsoleted by d25379e. Bump XLOG_PAGE_MAGIC because xl_logical_message changed and because 3fe3511d05 had omitted doing so. 3fe3511d05 additionally didn't bump catversion, but 7a542700d has done so since. Author: Petr Jelinek Reported-By: Andres Freund Discussion: 20160406142513.wotqy3ba3kanr423@alap3.anarazel.de
2016-04-06Generic Messages for Logical DecodingSimon Riggs
API and mechanism to allow generic messages to be inserted into WAL that are intended to be read by logical decoding plugins. This commit adds an optional new callback to the logical decoding API. Messages are either text or bytea. Messages can be transactional, or not, and are identified by a prefix to allow multiple concurrent decoding plugins. (Not to be confused with Generic WAL records, which are intended to allow crash recovery of extensible objects.) Author: Petr Jelinek and Andres Freund Reviewers: Artur Zakirov, Tomas Vondra, Simon Riggs Discussion: 5685F999.6010202@2ndquadrant.com
2016-04-01Add Generic WAL interfaceTeodor Sigaev
This interface is designed to give an access to WAL for extensions which could implement new access method, for example. Previously it was impossible because restoring from custom WAL would need to access system catalog to find a redo custom function. This patch suggests generic way to describe changes on page with standart layout. Bump XLOG_PAGE_MAGIC because of new record type. Author: Alexander Korotkov with a help of Petr Jelinek, Markus Nullmeier and minor editorization by my Reviewers: Petr Jelinek, Alvaro Herrera, Teodor Sigaev, Jim Nasby, Michael Paquier
2016-03-30Fix broken variable declarationAlvaro Herrera
Author: Konstantin Knizhnik
2016-03-30Enable logical slots to follow timeline switchesAlvaro Herrera
When decoding from a logical slot, it's necessary for xlog reading to be able to read xlog from historical (i.e. not current) timelines; otherwise, decoding fails after failover, because the archives are in the historical timeline. This is required to make "failover logical slots" possible; it currently has no other use, although theoretically it could be used by an extension that creates a slot on a standby and continues to replay from the slot when the standby is promoted. This commit includes a module in src/test/modules with functions to manipulate the slots (which is not otherwise possible in SQL code) in order to enable testing, and a new test in src/test/recovery to ensure that the behavior is as expected. Author: Craig Ringer Reviewed-By: Oleksii Kliukin, Andres Freund, Petr Jelínek
2016-03-30XLogReader general code cleanupAlvaro Herrera
Some minor tweaks and comment additions, for cleanliness sake and to avoid having the upcoming timeline-following patch be polluted with unrelated cleanup. Extracted from a larger patch by Craig Ringer, reviewed by Andres Freund, with some additions by myself.
2016-03-27Don't use !! but != 0/NULL to force boolean evaluation.Andres Freund
I introduced several uses of !! to force bit arithmetic to be boolean, but per discussion the project prefers != 0/NULL. Discussion: CA+TgmoZP5KakLGP6B4vUjgMBUW0woq_dJYi0paOz-My0Hwt_vQ@mail.gmail.com
2016-03-09Avoid unlikely data-loss scenarios due to rename() without fsync.Andres Freund
Renaming a file using rename(2) is not guaranteed to be durable in face of crashes. Use the previously added durable_rename()/durable_link_or_rename() in various places where we previously just renamed files. Most of the changed call sites are arguably not critical, but it seems better to err on the side of too much durability. The most prominent known case where the previously missing fsyncs could cause data loss is crashes at the end of a checkpoint. After the actual checkpoint has been performed, old WAL files are recycled. When they're filled, their contents are fdatasynced, but we did not fsync the containing directory. An OS/hardware crash in an unfortunate moment could then end up leaving that file with its old name, but new content; WAL replay would thus not replay it. Reported-By: Tomas Vondra Author: Michael Paquier, Tomas Vondra, Andres Freund Discussion: 56583BDD.9060302@2ndquadrant.com Backpatch: All supported branches
2016-03-09Introduce durable_rename() and durable_link_or_rename().Andres Freund
Renaming a file using rename(2) is not guaranteed to be durable in face of crashes; especially on filesystems like xfs and ext4 when mounted with data=writeback. To be certain that a rename() atomically replaces the previous file contents in the face of crashes and different filesystems, one has to fsync the old filename, rename the file, fsync the new filename, fsync the containing directory. This sequence is not generally adhered to currently; which exposes us to data loss risks. To avoid having to repeat this arduous sequence, introduce durable_rename(), which wraps all that. Also add durable_link_or_rename(). Several places use link() (with a fallback to rename()) to rename a file, trying to avoid replacing the target file out of paranoia. Some of those rename sequences need to be durable as well. There seems little reason extend several copies of the same logic, so centralize the link() callers. This commit does not yet make use of the new functions; they're used in a followup commit. Author: Michael Paquier, Andres Freund Discussion: 56583BDD.9060302@2ndquadrant.com Backpatch: All supported branches
2016-03-07Further improvements to c8f621c43.Andres Freund
Coverity and inspection for the issue addressed in fd45d16f found some questionable code. Specifically coverity noticed that the wrong length was added in ReorderBufferSerializeChange() - without immediate negative consequences as the variable isn't used afterwards. During code-review and testing I noticed that a bit of space was wasted when allocating tuple bufs in several places. Thirdly, the debug memset()s in ReorderBufferGetTupleBuf() reduce the error checking valgrind can do. Backpatch: 9.4, like c8f621c43.
2016-03-06Fix wrong allocation size in c8f621c43.Andres Freund
In c8f621c43 I forgot to account for MAXALIGN when allocating a new tuplebuf in ReorderBufferGetTupleBuf(). That happens to currently not cause active problems on a number of platforms because the affected pointer is already aligned, but others, like ppc and hppa, trigger this in the regression test, due to a debug memset clearing memory. Fix that. Backpatch: 9.4, like the previous commit.
2016-03-05logical decoding: Fix handling of large old tuples with replica identity full.Andres Freund
When decoding the old version of an UPDATE or DELETE change, and if that tuple was bigger than MaxHeapTupleSize, we either Assert'ed out, or failed in more subtle ways in non-assert builds. Normally individual tuples aren't bigger than MaxHeapTupleSize, with big datums toasted. But that's not the case for the old version of a tuple for logical decoding; the replica identity is logged as one piece. With the default replica identity btree limits that to small tuples, but that's not the case for FULL. Change the tuple buffer infrastructure to separate allocate over-large tuples, instead of always going through the slab cache. This unfortunately requires changing the ReorderBufferTupleBuf definition, we need to store the allocated size someplace. To avoid requiring output plugins to recompile, don't store HeapTupleHeaderData directly after HeapTupleData, but point to it via t_data; that leaves rooms for the allocated size. As there's no reason for an output plugin to look at ReorderBufferTupleBuf->t_data.header, remove the field. It was just a minor convenience having it directly accessible. Reported-By: Adam Dratwiński Discussion: CAKg6ypLd7773AOX4DiOGRwQk1TVOQKhNwjYiVjJnpq8Wo+i62Q@mail.gmail.com
2016-03-05logical decoding: old/newtuple in spooled UPDATE changes was switched around.Andres Freund
Somehow I managed to flip the order of restoring old & new tuples when de-spooling a change in a large transaction from disk. This happens to only take effect when a change is spooled to disk which has old/new versions of the tuple. That only is the case for UPDATEs where he primary key changed or where replica identity is changed to FULL. The tests didn't catch this because either spooled updates, or updates that changed primary keys, were tested; not both at the same time. Found while adding tests for the following commit. Backpatch: 9.4, where logical decoding was added
2016-03-05logical decoding: Tell reorderbuffer about all xids.Andres Freund
Logical decoding's reorderbuffer keeps transactions in an LSN ordered list for efficiency. To make that's efficiently possible upper-level xids are forced to be logged before nested subtransaction xids. That only works though if these records are all looked at: Unfortunately we didn't do so for e.g. row level locks, which are otherwise uninteresting for logical decoding. This could lead to errors like: "ERROR: subxact logged without previous toplevel record". It's not sufficient to just look at row locking records, the xid could appear first due to a lot of other types of records (which will trigger the transaction to be marked logged with MarkCurrentTransactionIdLoggedIfAny). So invent infrastructure to tell reorderbuffer about xids seen, when they'd otherwise not pass through reorderbuffer.c. Reported-By: Jarred Ward Bug: #13844 Discussion: 20160105033249.1087.66040@wrigleys.postgresql.org Backpatch: 9.4, where logical decoding was added
2016-03-02logical decoding: fix decoding of a commit's commit time.Andres Freund
When adding replication origins in 5aa235042, I somehow managed to set the timestamp of decoded transactions to InvalidXLogRecptr when decoding one made without a replication origin. Fix that, and the wrong type of the new commit_time variable. This didn't trigger a regression test failure because we explicitly don't show commit timestamps in the regression tests, as they obviously are variable. Add a test that checks that a decoded commit's timestamp is within minutes of NOW() from before the commit. Reported-By: Weiping Qu Diagnosed-By: Artur Zakirov Discussion: 56D4197E.9050706@informatik.uni-kl.de, 56D42918.1010108@postgrespro.ru Backpatch: 9.5, where 5aa235042 originates.
2016-02-12Make builtin lwlock tranche names consistent.Robert Haas
Previously, we had a mix of styles. Amit Kapila
2016-02-02Make all built-in lwlock tranche IDs fixed.Robert Haas
This makes the values more stable, which seems like a good thing for anybody who needs to look at at them. Alexander Korotkov and Amit Kapila
2016-02-01Fix typos in commentsMagnus Hagander
Author: Michael Paquier
2016-01-20Refactor to create generic WAL page read callbackSimon Riggs
Previously we didn’t have a generic WAL page read callback function, surprisingly. Logical decoding has logical_read_local_xlog_page(), which was actually generic, so move that to xlogfunc.c and rename to read_local_xlog_page(). Maintain logical_read_local_xlog_page() so existing callers still work. As requested by Michael Paquier, Alvaro Herrera and Andres Freund
2016-01-09Clean up some lack-of-STRICT issues in the core code, too.Tom Lane
A scan for missed proisstrict markings in the core code turned up these functions: brin_summarize_new_values pg_stat_reset_single_table_counters pg_stat_reset_single_function_counters pg_create_logical_replication_slot pg_create_physical_replication_slot pg_drop_replication_slot The first three of these take OID, so a null argument will normally look like a zero to them, resulting in "ERROR: could not open relation with OID 0" for brin_summarize_new_values, and no action for the pg_stat_reset_XXX functions. The other three will dump core on a null argument, though this is mitigated by the fact that they won't do so until after checking that the caller is superuser or has rolreplication privilege. In addition, the pg_logical_slot_get/peek[_binary]_changes family was intentionally marked nonstrict, but failed to make nullness checks on all the arguments; so again a null-pointer-dereference crash is possible but only for superusers and rolreplication users. Add the missing ARGISNULL checks to the latter functions, and mark the former functions as strict in pg_proc. Make that change in the back branches too, even though we can't force initdb there, just so that installations initdb'd in future won't have the issue. Since none of these bugs rise to the level of security issues (and indeed the pg_stat_reset_XXX functions hardly misbehave at all), it seems sufficient to do this. In addition, fix some order-of-operations oddities in the slot_get_changes family, mostly cosmetic, but not the part that moves the function's last few operations into the PG_TRY block. As it stood, there was significant risk for an error to exit without clearing historical information from the system caches. The slot_get_changes bugs go back to 9.4 where that code was introduced. Back-patch appropriate subsets of the pg_proc changes into all active branches, as well.
2016-01-02Update copyright for 2016Bruce Momjian
Backpatch certain files through 9.1
2015-12-18Fix copy-and-paste error in logical decoding callback.Robert Haas
This could result in the error context misidentifying where the error actually occurred. Craig Ringer
2015-11-09Set replication origin when decoding commit records.Andres Freund
By accident the replication origin was not set properly in DecodeCommit(). That's bad because the origin is passed to the output plugins origin filter, and accessible from the output plugin via ReorderBufferTXN->origin_id. Accessing the origin of individual changes worked before the fix, which is why this wasn't notices earlier. Reported-By: Craig Ringer Author: Craig Ringer Discussion: CAMsr+YFhBJLp=qfSz3-J+0P1zLkE8zNXM2otycn20QRMx380gw@mail.gmail.com Backpatch: 9.5, where replication origins where introduced
2015-10-28Message style improvementsPeter Eisentraut
Message style, plurals, quoting, spelling, consistency with similar messages
2015-10-06Remove more volatile qualifiers.Robert Haas
Prior to commit 0709b7ee72e4bc71ad07b7120acd117265ab51d0, access to variables within a spinlock-protected critical section had to be done through a volatile pointer, but that should no longer be necessary. This continues work begun in df4077cda2eae3eb4a5cf387da0c1e7616e73204 and 6ba4ecbf477e0b25dd7bde1b0c4e07fc2da19348. Thomas Munro and Michael Paquier
2015-09-28Fix "sesssion" typoAlvaro Herrera
It was introduced alongside replication origins, by commit 5aa2350426c, so backpatch to 9.5. Pointed out by Fujii Masao
2015-09-05Fix misc typos.Heikki Linnakangas
Oskari Saarenmaa. Backpatch to stable branches where applicable.
2015-08-15Don't use function definitions looking like old-style ones.Andres Freund
This fixes a bunch of somewhat pedantic warnings with new compilers. Since by far the majority of other functions definitions use the (void) style it just seems to be consistent to do so as well in the remaining few places.
2015-08-11Don't include rel.h when relcache.h is sufficientAlvaro Herrera
Trivial change to reduce exposure of rel.h.
2015-08-11Allow pg_create_physical_replication_slot() to reserve WAL.Andres Freund
When creating a physical slot it's often useful to immediately reserve the current WAL position instead of only doing after the first feedback message arrives. That e.g. allows slots to guarantee that all the WAL for a base backup will be available afterwards. Logical slots already have to reserve WAL during creation, so generalize that logic into being usable for both physical and logical slots. Catversion bump because of the new parameter. Author: Gurjeet Singh Reviewed-By: Andres Freund Discussion: CABwTF4Wh_dBCzTU=49pFXR6coR4NW1ynb+vBqT+Po=7fuq5iCw@mail.gmail.com
2015-08-11Introduce macros determining if a replication slot is physical or logical.Andres Freund
These make the code a bit easier to read, and make it easier to add a more explicit notion of a slot's type at some point in the future. Author: Gurjeet Singh Discussion: CABwTF4Wh_dBCzTU=49pFXR6coR4NW1ynb+vBqT+Po=7fuq5iCw@mail.gmail.com
2015-08-11Minor cleanups in slot related code.Andres Freund
Fix a bunch of typos, and remove two superflous includes. Author: Gurjeet Singh Discussion: CABwTF4Wh_dBCzTU=49pFXR6coR4NW1ynb+vBqT+Po=7fuq5iCw@mail.gmail.com Backpatch: 9.4
2015-08-07Address points made in post-commit review of replication origins.Andres Freund
Amit reviewed the replication origins patch and made some good points. Address them. This fixes typos in error messages, docs and comments and adds a missing error check (although in a should-never-happen scenario). Discussion: CAA4eK1JqUBVeWWKwUmBPryFaje4190ug0y-OAUHWQ6tD83V4xg@mail.gmail.com Backpatch: 9.5, where replication origins were introduced.
2015-08-05Fix debug message output when connecting to a logical slot.Andres Freund
Previously the message erroneously printed the same LSN twice as the assignment to the start_lsn variable was before the message. Correct that. Reported-By: Marko Tiikkaja Author: Marko Tiikkaja Backpatch: 9.5, where logical decoding was introduced
2015-07-07Fix logical decoding bug leading to inefficient reopening of files.Andres Freund
When spilling transaction data to disk a simple typo caused the output file to be closed and reopened for every serialized change. That happens to not have a huge impact on linux, which is why it probably wasn't noticed so far, but on windows that appears to trigger actual disk writes after every change. Not fun. The bug fortunately does not have any impact besides speed. A change could end up being in the wrong segment (last instead of next), but since we read all files to the end, that's just ugly, not really problematic. It's not a problem to upgrade, since transaction spill files do not persist across restarts. Bug: #13484 Reported-By: Olivier Gosseaume Discussion: 20150703090217.1190.63940@wrigleys.postgresql.org Backpatch to 9.4, where logical decoding was added.
2015-05-23pgindent run for 9.5Bruce Momjian
2015-05-20Fix more typos in comments.Heikki Linnakangas
Patch by CharSyam, plus a few more I spotted with grep.
2015-05-20Collection of typo fixes.Heikki Linnakangas
Use "a" and "an" correctly, mostly in comments. Two error messages were also fixed (they were just elogs, so no translation work required). Two function comments in pg_proc.h were also fixed. Etsuro Fujita reported one of these, but I found a lot more with grep. Also fix a few other typos spotted while grepping for the a/an typos. For example, "consists out of ..." -> "consists of ...". Plus a "though"/ "through" mixup reported by Euler Taveira. Many of these typos were in old code, which would be nice to backpatch to make future backpatching easier. But much of the code was new, and I didn't feel like crafting separate patches for each branch. So no backpatching.
2015-05-17Fix typos in commentsMagnus Hagander
Dmitriy Olshevskiy
2015-05-08Add support for INSERT ... ON CONFLICT DO NOTHING/UPDATE.Andres Freund
The newly added ON CONFLICT clause allows to specify an alternative to raising a unique or exclusion constraint violation error when inserting. ON CONFLICT refers to constraints that can either be specified using a inference clause (by specifying the columns of a unique constraint) or by naming a unique or exclusion constraint. DO NOTHING avoids the constraint violation, without touching the pre-existing row. DO UPDATE SET ... [WHERE ...] updates the pre-existing tuple, and has access to both the tuple proposed for insertion and the existing tuple; the optional WHERE clause can be used to prevent an update from being executed. The UPDATE SET and WHERE clauses have access to the tuple proposed for insertion using the "magic" EXCLUDED alias, and to the pre-existing tuple using the table name or its alias. This feature is often referred to as upsert. This is implemented using a new infrastructure called "speculative insertion". It is an optimistic variant of regular insertion that first does a pre-check for existing tuples and then attempts an insert. If a violating tuple was inserted concurrently, the speculatively inserted tuple is deleted and a new attempt is made. If the pre-check finds a matching tuple the alternative DO NOTHING or DO UPDATE action is taken. If the insertion succeeds without detecting a conflict, the tuple is deemed inserted. To handle the possible ambiguity between the excluded alias and a table named excluded, and for convenience with long relation names, INSERT INTO now can alias its target table. Bumps catversion as stored rules change. Author: Peter Geoghegan, with significant contributions from Heikki Linnakangas and Andres Freund. Testing infrastructure by Jeff Janes. Reviewed-By: Heikki Linnakangas, Andres Freund, Robert Haas, Simon Riggs, Dean Rasheed, Stephen Frost and many others.
2015-05-04Fix typosPeter Eisentraut
Author: Erik Rijkers <er@xs4all.nl>
2015-05-01Copy editing of the replication origins patch.Andres Freund
Michael Paquier and myself.
2015-04-30Correct replication origin's use of UINT16_MAX to PG_UINT16_MAX.Andres Freund
We can't rely on UINT16_MAX being present, which is why we introduced PG_UINT16_MAX... Buildfarm animal bowerbird via Andrew Gierth.
2015-04-29Introduce replication progress tracking infrastructure.Andres Freund
When implementing a replication solution ontop of logical decoding, two related problems exist: * How to safely keep track of replication progress * How to change replication behavior, based on the origin of a row; e.g. to avoid loops in bi-directional replication setups The solution to these problems, as implemented here, consist out of three parts: 1) 'replication origins', which identify nodes in a replication setup. 2) 'replication progress tracking', which remembers, for each replication origin, how far replay has progressed in a efficient and crash safe manner. 3) The ability to filter out changes performed on the behest of a replication origin during logical decoding; this allows complex replication topologies. E.g. by filtering all replayed changes out. Most of this could also be implemented in "userspace", e.g. by inserting additional rows contain origin information, but that ends up being much less efficient and more complicated. We don't want to require various replication solutions to reimplement logic for this independently. The infrastructure is intended to be generic enough to be reusable. This infrastructure also replaces the 'nodeid' infrastructure of commit timestamps. It is intended to provide all the former capabilities, except that there's only 2^16 different origins; but now they integrate with logical decoding. Additionally more functionality is accessible via SQL. Since the commit timestamp infrastructure has also been introduced in 9.5 (commit 73c986add) changing the API is not a problem. For now the number of origins for which the replication progress can be tracked simultaneously is determined by the max_replication_slots GUC. That GUC is not a perfect match to configure this, but there doesn't seem to be sufficient reason to introduce a separate new one. Bumps both catversion and wal page magic. Author: Andres Freund, with contributions from Petr Jelinek and Craig Ringer Reviewed-By: Heikki Linnakangas, Petr Jelinek, Robert Haas, Steve Singer Discussion: 20150216002155.GI15326@awork2.anarazel.de, 20140923182422.GA15776@alap3.anarazel.de, 20131114172632.GE7522@alap2.anarazel.de