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From Alexey Loshkarev <elf2...@gmail.com>
Subject Re: view response with duplicate id's
Date Thu, 07 Oct 2010 19:01:38 GMT
Can't reproduce it with this script.
If I send you copy of my buggy database, will it help to improve couchdb?

2010/10/7 Paul Davis <paul.joseph.davis@gmail.com>:
> Alexey,
>
> I tried writing a script that'd hammer a single document and make
> random view requests to see if I could reproduce the issue. Currently
> the test doc is on revision 6,000 or so and I've not reproduced your
> issue. I've included the script below, can you try it or see anything
> that I should add to try and get closer to your situation?
>
> Paul
>
> #! /usr/bin/env python
>
> import random
> import couchdbkit
>
> def main():
>    server = couchdbkit.Server("http://127.0.0.1:5984/")
>    db = server.get_or_create_db("foo")
>
>    ddocid = "_design/baz"
>    if ddocid not in db:
>        db[ddocid] = {"views": {"foo": {"map": """
>            function(doc) {emit(doc._id, doc.value);}
>        """}}}
>
>    assert 0 <= len(db.view("baz/foo")) <= 1
>
>    docid = "foo"
>
>    if docid in db:
>        doc = db[docid]
>    else:
>        doc = {"_id": "foo", "value": 1}
>        db[docid] = doc
>
>    for i in range(1200):
>        db[docid] = doc
>        doc = db[docid]
>        if random.random() < 0.33:
>            assert len(db.view("baz/foo")) == 1
>
> if __name__ == '__main__':
>    main()
>
>
> On Thu, Oct 7, 2010 at 1:46 PM, Alexey Loshkarev <elf2001@gmail.com> wrote:
>> If it helps..
>>
>> This q_* documents are some such of state data. They are changed very
>> frequently.
>> I have 12 q_* documents and they may be changed 10-30 time per minute.
>> May be, there are race condition problem in couchdb in view creation?
>>
>>
>> 2010/10/7 Alexey Loshkarev <elf2001@gmail.com>:
>>> I just tried to move view function to separate design doc and no
>>> success - duplicates (with same revision) in view response.
>>>
>>>
>>> 2010/10/7 Paul Davis <paul.joseph.davis@gmail.com>:
>>>> Alexey,
>>>>
>>>> Can you show the other views you have in your design doc? Or
>>>> alternatively, try moving this view to its own design doc?
>>>>
>>>> Paul
>>>>
>>>> On Thu, Oct 7, 2010 at 1:07 PM, Alexey Loshkarev <elf2001@gmail.com>
wrote:
>>>>> Same problem appears again.
>>>>> What was done till yesterday:
>>>>> 1. Created new database at node2
>>>>> 2. Replicated from node1 to node2
>>>>> 3. Checked. _all_docs return only unique rows. queue/all returns only
>>>>> unique rows
>>>>>
>>>>> After a few hour of stable work, couchdb produce duplicates too.
>>>>> This time, no duplicate documents (_all_docs has only unique strings),
>>>>> but duplicate view response.
>>>>> Remove view index (between couchdb restarts) doesn't help. Couchdb
>>>>> produce stable duplicates in view.
>>>>>
>>>>> View function:
>>>>> function(doc) {
>>>>>  if (doc.type == "queue") {
>>>>>    log("BUG TEST id:" + doc._id + ", rev:" + doc._rev);
>>>>>    emit(doc.ordering, doc);
>>>>>  }
>>>>> }
>>>>>
>>>>> Response:
>>>>> $ curl http://localhost:5984/exhaust/_design/queues/_view/all
>>>>> {"total_rows":15,"offset":0,"rows":[
>>>>> ....
>>>>> {"id":"q_nikolaevka","key":10,"value":{"_id":"q_nikolaevka","_rev":"16181-ae5e5cca96b0491f266bc97c37a88f47","name":"\u041d\u0418\u041a\u041e\u041b\u0410\u0415\u0412\u041a\u0410","default":false,"cars":[],"drivers":[],"ordering":10,"type":"queue"}},
>>>>> {"id":"q_nikolaevka","key":10,"value":{"_id":"q_nikolaevka","_rev":"16176-3a7bbd128bfb257fd746dfd80769b6fc","name":"\u041d\u0418\u041a\u041e\u041b\u0410\u0415\u0412\u041a\u0410","default":false,"cars":[],"ordering":10,"type":"queue","drivers":[]}},
>>>>> ...
>>>>> ]}
>>>>>
>>>>>
>>>>> Saw that? Two documents with different revisions in it!
>>>>>
>>>>> Also, couch.log consists of 3 (!) calls of this function for one document:
>>>>> [Thu, 07 Oct 2010 16:53:51 GMT] [info] [<0.180.0>] OS Process
>>>>> #Port<0.2132> Log :: BUG TEST id:q_nikolaevka,
>>>>> rev:16175-11cedeb529991cf60193d436d1a567e9
>>>>> [Thu, 07 Oct 2010 16:53:51 GMT] [info] [<0.180.0>] OS Process
>>>>> #Port<0.2132> Log :: BUG TEST id:q_nikolaevka,
>>>>> rev:16176-3a7bbd128bfb257fd746dfd80769b6fc
>>>>> [Thu, 07 Oct 2010 16:53:51 GMT] [info] [<0.180.0>] OS Process
>>>>> #Port<0.2132> Log :: BUG TEST id:q_nikolaevka,
>>>>> rev:16181-ae5e5cca96b0491f266bc97c37a88f47
>>>>>
>>>>>
>>>>> Then I do compact to eliminate old revisions.
>>>>> And now I have 3 duplicates per q_nikolaevka with same revisions!
>>>>>
>>>>> I think, I found problem. This document has 1000 revisions in database
>>>>> and here (http://wiki.apache.org/couchdb/HTTP_database_API) is
>>>>> described default maximum of 1000 revisions of document.
>>>>>
>>>>>
>>>>>
>>>>> 2010/10/7 Alexey Loshkarev <elf2001@gmail.com>:
>>>>>> Haha!
>>>>>> Fresh replication (into new database) eliminates duplicates and I
can
>>>>>> sleep quietly.
>>>>>>
>>>>>>
>>>>>> 2010/10/7 Alexey Loshkarev <elf2001@gmail.com>:
>>>>>>> P.S. dmesg doesn't show any hardware problems (bad blocks, segfaults
>>>>>>> and so on).
>>>>>>> P.P.S. I think, I was migrate 0.10.1 -> 1.0.1 without database
>>>>>>> replication, so it may be my fault.
>>>>>>>
>>>>>>> 2010/10/7 Alexey Loshkarev <elf2001@gmail.com>:
>>>>>>>> I think, this is database file corruption. Query _all_docs
returns me
>>>>>>>> a lot of duplicates (about 3.000 duplicates in ~350.000-documents
>>>>>>>> database).
>>>>>>>>
>>>>>>>>
>>>>>>>> [12:17:48 root@node2 (~)]# curl
>>>>>>>> http://localhost:5984/exhaust/_all_docs > all_docs
>>>>>>>>  % Total    % Received % Xferd  Average Speed   Time
   Time     Time  Current
>>>>>>>>                                 Dload  Upload
  Total   Spent    Left  Speed
>>>>>>>> 100 37.7M    0 37.7M    0     0  1210k      0 --:--:--
 0:00:31 --:--:--  943k
>>>>>>>> [12:18:23 root@node2 (~)]# wc -l all_docs
>>>>>>>> 325102 all_docs
>>>>>>>> [12:18:27 root@node2 (~)]# uniq all_docs |wc -l
>>>>>>>> 322924
>>>>>>>>
>>>>>>>>
>>>>>>>> Node1 has duplicates too, but very small amount:
>>>>>>>> [12:18:48 root@node1 (~)]# curl
>>>>>>>> http://localhost:5984/exhaust/_all_docs > all_docs
>>>>>>>>  % Total    % Received % Xferd  Average Speed   Time
   Time     Time  Current
>>>>>>>>                                 Dload  Upload
  Total   Spent    Left  Speed
>>>>>>>> 100 38.6M    0 38.6M    0     0   693k      0 --:--:--
 0:00:57 --:--:-- 55809
>>>>>>>> [12:19:57 root@node1 (~)]# wc -l all_docs
>>>>>>>> 332714 all_docs
>>>>>>>> [12:20:54 root@node1 (~)]# uniq all_docs |wc -l
>>>>>>>> 332523
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> 2010/10/7 Alexey Loshkarev <elf2001@gmail.com>:
>>>>>>>>> I can't say what specific it may be, so let dive into
history of this
>>>>>>>>> database(s).
>>>>>>>>>
>>>>>>>>> First (before a 5-6 weeks) it was node2 server with couchdb
v10.1.
>>>>>>>>> There was testing database on it. There were alot of
structural
>>>>>>>>> changes, view updates and so on.
>>>>>>>>> Than it becomes production and starts working ok.
>>>>>>>>> Than we realize we need backup, and best - online backup
(as we have
>>>>>>>>> couchdb we can do this).
>>>>>>>>> So, there appears node1 server with couchdb 1.0.1. I
replicated node2
>>>>>>>>> to node1, than initiates continuous replication node1
-> node2 and
>>>>>>>>> node2 -> node1. All clients works with node2 only.
All works fine
>>>>>>>>> about a month.
>>>>>>>>> Few days before we was at peak load, so I'v want to use
node1 and
>>>>>>>>> node2 simultaneously. This was done by round-robin on
DNS (host db
>>>>>>>>> returns 2 different IP - node1's ip and node2's IP).
All works fine
>>>>>>>>> about 5 minutes, than I gave first conflict (view queues/all
returns
>>>>>>>>> two identical documents, one - actual version, second
- conflicted
>>>>>>>>> revision, document with field _conflict="....."). Document
ID was
>>>>>>>>> q_tsentr.
>>>>>>>>> As I don't has conflict resolver yet, I resolves conflict
manually by
>>>>>>>>> deleting conflicted revision. I'v also disables round-robin
and move
>>>>>>>>> all load to node2 to avoid conflicts for a while to wrote
conflict
>>>>>>>>> resolver.
>>>>>>>>>
>>>>>>>>> It works ok (node1 and node2 in mutual replications,
active load on
>>>>>>>>> node2) till yesterday.
>>>>>>>>> Yesterday operator call me he has duplicate data in program.
At this
>>>>>>>>> queues/all returns 1 duplicated document - the same as
few days before
>>>>>>>>> (id = q_tsentr). One row consists of actual document
version, another
>>>>>>>>> row consists of old revision with field _conflicted_revision="some
old
>>>>>>>>> revision".
>>>>>>>>>
>>>>>>>>> I tried to delete this revision but without success.
GET for
>>>>>>>>> q_tsentr?rev="some old revision" returns valid document.
DELETE
>>>>>>>>> q_tsentr?rev="some old revision" gaves me 409 error.
>>>>>>>>> Here are log files (node2):
>>>>>>>>>
>>>>>>>>> [Wed, 06 Oct 2010 12:17:19 GMT] [info] [<0.7239.1462>]
10.0.0.41 - -
>>>>>>>>> 'GET' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
200
>>>>>>>>> [Wed, 06 Oct 2010 12:17:30 GMT] [info] [<0.7245.1462>]
10.0.0.41 - -
>>>>>>>>> 'GET' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
200
>>>>>>>>> [Wed, 06 Oct 2010 12:17:35 GMT] [info] [<0.7287.1462>]
10.0.0.41 - -
>>>>>>>>> 'GET' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
200
>>>>>>>>> [Wed, 06 Oct 2010 12:17:43 GMT] [info] [<0.7345.1462>]
10.0.0.41 - -
>>>>>>>>> 'GET' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
200
>>>>>>>>> [Wed, 06 Oct 2010 12:18:02 GMT] [info] [<0.7864.1462>]
10.0.0.41 - -
>>>>>>>>> 'DELETE' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
>>>>>>>>> 409
>>>>>>>>> [Wed, 06 Oct 2010 12:18:29 GMT] [info] [<0.8331.1462>]
10.0.0.41 - -
>>>>>>>>> 'GET' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
200
>>>>>>>>> [Wed, 06 Oct 2010 12:18:39 GMT] [info] [<0.8363.1462>]
10.0.0.41 - -
>>>>>>>>> 'DELETE' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
>>>>>>>>> 409
>>>>>>>>> [Wed, 06 Oct 2010 12:38:19 GMT] [info] [<0.16765.1462>]
10.0.0.41 - -
>>>>>>>>> 'GET' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
200
>>>>>>>>> [Wed, 06 Oct 2010 12:40:40 GMT] [info] [<0.17337.1462>]
10.0.0.41 - -
>>>>>>>>> 'GET' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
200
>>>>>>>>> [Wed, 06 Oct 2010 12:40:45 GMT] [info] [<0.17344.1462>]
10.0.0.41 - -
>>>>>>>>> 'DELETE' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
>>>>>>>>> 404
>>>>>>>>>
>>>>>>>>> Logs at node1:
>>>>>>>>>
>>>>>>>>> [Wed, 06 Oct 2010 12:17:46 GMT] [info] [<0.25979.462>]
10.20.20.13 - -
>>>>>>>>> 'GET' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
200
>>>>>>>>> [Wed, 06 Oct 2010 12:17:56 GMT] [info] [<0.26002.462>]
10.20.20.13 - -
>>>>>>>>> 'DELETE' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
>>>>>>>>> 200
>>>>>>>>> [Wed, 06 Oct 2010 12:21:25 GMT] [info] [<0.27133.462>]
10.20.20.13 - -
>>>>>>>>> 'DELETE' /exhaust/q_tsentr?rev=all 404
>>>>>>>>> [Wed, 06 Oct 2010 12:21:49 GMT] [info] [<0.27179.462>]
10.20.20.13 - -
>>>>>>>>> 'DELETE' /exhaust/q_tsentr?revs=true 404
>>>>>>>>> [Wed, 06 Oct 2010 12:24:41 GMT] [info] [<0.28959.462>]
10.20.20.13 - -
>>>>>>>>> 'DELETE' /exhaust/q_tsentr?revs=true 404
>>>>>>>>> [Wed, 06 Oct 2010 12:38:07 GMT] [info] [<0.10362.463>]
10.20.20.13 - -
>>>>>>>>> 'GET' /exhaust/q_tsentr?revs=all 404
>>>>>>>>> [Wed, 06 Oct 2010 12:38:23 GMT] [info] [<0.10534.463>]
10.20.20.13 - -
>>>>>>>>> 'GET' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
200
>>>>>>>>> [Wed, 06 Oct 2010 12:40:25 GMT] [info] [<0.12014.463>]
10.20.20.13 - -
>>>>>>>>> 'GET' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
200
>>>>>>>>> [Wed, 06 Oct 2010 12:40:33 GMT] [info] [<0.12109.463>]
10.20.20.13 - -
>>>>>>>>> 'DELETE' /exhaust/q_tsentr?rev=27144-f516ac68e697874eef9c7562f3e2e229
>>>>>>>>> 404
>>>>>>>>>
>>>>>>>>> So, I deletes this document and creates new one (id -
q_tsentr2).
>>>>>>>>> It will works fine about hour.
>>>>>>>>>
>>>>>>>>> Node2 has undeletable duplicate, so I move all clients
to node1. There
>>>>>>>>> were now such problem, view response was correct.
>>>>>>>>>
>>>>>>>>> Than I tried to recover database at node2. I stops, deletes
view index
>>>>>>>>> files and start couchdb again. Than i ping all view to
recreate index.
>>>>>>>>> At the end ot this procedure, i saw duplicates of identical
rows (see
>>>>>>>>> first letter in this thread). Node1 has no such problems,
so I stops
>>>>>>>>> replication, leave load on node1 and go for crying into
this maillist.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> 2010/10/6 Paul Davis <paul.joseph.davis@gmail.com>:
>>>>>>>>>> It was noted on IRC that I should give a bit more
explanation.
>>>>>>>>>>
>>>>>>>>>> With the information that you've provided there are
two possible
>>>>>>>>>> explanations. Either your client code is not doing
what you expect or
>>>>>>>>>> you've triggered a really crazy bug in the view indexer
that caused it
>>>>>>>>>> to reindex a database without invalidating a view
and not removing
>>>>>>>>>> keys for docs when it reindexed.
>>>>>>>>>>
>>>>>>>>>> Given that no one has reported anything remotely
like this and I can't
>>>>>>>>>> immediately see a code path that would violate so
many behaviours in
>>>>>>>>>> the view updater, I'm leaning towards this being
an issue in the
>>>>>>>>>> client code.
>>>>>>>>>>
>>>>>>>>>> If there was something specific that changed since
the view worked,
>>>>>>>>>> that might illuminate what could cause this sort
of behaviour if it is
>>>>>>>>>> indeed a bug in CouchDB.
>>>>>>>>>>
>>>>>>>>>> HTH,
>>>>>>>>>> Paul Davis
>>>>>>>>>>
>>>>>>>>>> On Wed, Oct 6, 2010 at 12:24 PM, Alexey Loshkarev
<elf2001@gmail.com> wrote:
>>>>>>>>>>> I have such view function (map only, without
reduce)
>>>>>>>>>>>
>>>>>>>>>>> function(doc) {
>>>>>>>>>>>  if (doc.type == "queue") {
>>>>>>>>>>>    emit(doc.ordering, doc.drivers);
>>>>>>>>>>>  }
>>>>>>>>>>> }
>>>>>>>>>>>
>>>>>>>>>>> It works perfect till yesterday, but today it
start return duplicates
>>>>>>>>>>> Example:
>>>>>>>>>>> $ curl http://node2:5984/exhaust/_design/queues/_view/all
>>>>>>>>>>>
>>>>>>>>>>> {"total_rows":46,"offset":0,"rows":[
>>>>>>>>>>> {"id":"q_mashinyi-v-gorode","key":0,"value":["d_mironets_ivan","d_smertin_ivan","d_kasyanenko_sergej","d_chabotar_aleksandr","d_martyinenko_yurij","d_krikunenko_aleksandr"]},
>>>>>>>>>>> {"id":"q_mashinyi-v-gorode","key":0,"value":["d_mironets_ivan","d_smertin_ivan","d_kasyanenko_sergej","d_chabotar_aleksandr","d_martyinenko_yurij","d_krikunenko_aleksandr"]},
>>>>>>>>>>> {"id":"q_mashinyi-v-gorode","key":0,"value":["d_mironets_ivan","d_smertin_ivan","d_kasyanenko_sergej","d_chabotar_aleksandr","d_martyinenko_yurij","d_krikunenko_aleksandr"]},
>>>>>>>>>>> ......
>>>>>>>>>>> {"id":"q_oblasnaya","key":2,"value":["d_kramarenko_viktor","d_skorodzievskij_eduard"]},
>>>>>>>>>>> {"id":"q_oblasnaya","key":2,"value":["d_kramarenko_viktor","d_skorodzievskij_eduard"]},
>>>>>>>>>>> {"id":"q_oblasnaya","key":2,"value":["d_kramarenko_viktor","d_skorodzievskij_eduard"]},
>>>>>>>>>>> ........
>>>>>>>>>>> {"id":"q_otstoj","key":11,"value":["d_gavrilenko_aleksandr","d_klishnev_sergej"]}
>>>>>>>>>>> ]}
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> I tried to restart server, recreate view (remove
view index file),
>>>>>>>>>>> compact view and database and none of this helps,
it still returns
>>>>>>>>>>> duplicates.
>>>>>>>>>>> What happens? How to avoid it in the future?
>>>>>>>>>>>
>>>>>>>>>>> --
>>>>>>>>>>> ----------------
>>>>>>>>>>> Best regards
>>>>>>>>>>> Alexey Loshkarev
>>>>>>>>>>> mailto:elf2001@gmail.com
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> ----------------
>>>>>>>>> Best regards
>>>>>>>>> Alexey Loshkarev
>>>>>>>>> mailto:elf2001@gmail.com
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> ----------------
>>>>>>>> Best regards
>>>>>>>> Alexey Loshkarev
>>>>>>>> mailto:elf2001@gmail.com
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> ----------------
>>>>>>> Best regards
>>>>>>> Alexey Loshkarev
>>>>>>> mailto:elf2001@gmail.com
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> ----------------
>>>>>> Best regards
>>>>>> Alexey Loshkarev
>>>>>> mailto:elf2001@gmail.com
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> ----------------
>>>>> Best regards
>>>>> Alexey Loshkarev
>>>>> mailto:elf2001@gmail.com
>>>>>
>>>>
>>>
>>>
>>>
>>> --
>>> ----------------
>>> Best regards
>>> Alexey Loshkarev
>>> mailto:elf2001@gmail.com
>>>
>>
>>
>>
>> --
>> ----------------
>> Best regards
>> Alexey Loshkarev
>> mailto:elf2001@gmail.com
>>
>



-- 
----------------
Best regards
Alexey Loshkarev
mailto:elf2001@gmail.com

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