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From Jonathan Johnson <...@core-apps.com>
Subject Re: all_dbs_active error, not sure how to "fix"
Date Fri, 22 Apr 2011 14:45:48 GMT
As I mentioned in my email, even after killing all of my server
processes, couch doesn't give back the open databases.

I am using Erlang 5.6.5 on 64-bit, so that could very well be the
issue. How can I tell if I'm using the version that has the bug -- is
it fixed in the current version of Erlang? I believe I'm using erlang
installed from yum.

Thanks for your help!
-Jon



On Fri, Apr 22, 2011 at 9:36 AM, Filipe David Manana
<fdmanana@apache.org> wrote:
> On Fri, Apr 22, 2011 at 3:30 PM, Jonathan Johnson <jon@core-apps.com> wrote:
>> By doing that, it will increase the number of possible open files
>> (although I admit I'm significantly lower than my current limit). My
>> point is that I'm never actively connecting to 130 databases, so why
>> is couch keeping them open? Shouldn't it recycle databases that hadn't
>> been connected to recently?
>
> Yes it should. I dunno, perhaps your application or library is doing
> database accesses behind the scenes.
> Also, if you change your machine's clock while Couch is running, I
> think it might prevent it from properly recycling databases.
> Finally, if you're using Erlang OTP R14B02 on a 64 bits machine,
> there's a bug in that particular release regarding insertion in
> ordered ets tables, which might cause Couch to not do the recycling as
> it should.
>
>>
>> -Jon
>>
>>
>> On Fri, Apr 22, 2011 at 9:05 AM, Filipe David Manana
>> <fdmanana@apache.org> wrote:
>>> Look at the "max_dbs_open" configuration parameter in the .ini files
>>> and increase it to a higher value.
>>>
>>> On Fri, Apr 22, 2011 at 3:01 PM, Jonathan Johnson <jon@core-apps.com> wrote:
>>>> I'm running couchdb 1.0.2 on CentOS 5.5. The databases are on an ext4
>>>> formatted drive.
>>>>
>>>> I have 209 databases, but they're never truly active at the same time.
>>>> Our stack is written in ruby. The web layer switches between active
>>>> databases depending on the url. However, we have 16 web processes, so
>>>> in theory the maximum number of truly active databases is 16.
>>>>
>>>> We also have a daemon process that loops through a chunk of the
>>>> databases periodically. However, it's one thread, and as such also
>>>> only truly works with one database at a time.
>>>>
>>>> My understanding is that CouchRest doesn't keep HTTP connections alive
>>>> for multiple requests, but I don't know that for sure. I have even
>>>> gone as far as putting in manual garbage collection calls in my daemon
>>>> to ensure that any stranded connection objects will be collected.
>>>>
>>>> With all of that, however, I eventually get into a state where I get
>>>> the all_dbs_active error. It doesn't happen often -- last time was
>>>> nearly 3 weeks ago. However, once it gets in the state, restarting all
>>>> of my clients doesn't release the databases. The only way to recover
>>>> is to restart couch.
>>>>
>>>> open_os_files was at 2308 before I restarted it this morning, which is
>>>> less than the current limit set (4096).
>>>>
>>>> I guess I feel like this is an issue inside of couch because even if I
>>>> quit all of my active server processes that connect to couch, couch
>>>> never frees up the open databases. I can hit it one-off from my
>>>> browser and still get the error, even though I'm the only active
>>>> connection.
>>>>
>>>> Has anyone else seen this? Any ideas of what I can try to prevent this
>>>> from happening?
>>>>
>>>> Thanks!
>>>> -Jon
>>>>
>>>
>>>
>>>
>>> --
>>> Filipe David Manana,
>>> fdmanana@gmail.com, fdmanana@apache.org
>>>
>>> "Reasonable men adapt themselves to the world.
>>>  Unreasonable men adapt the world to themselves.
>>>  That's why all progress depends on unreasonable men."
>>>
>>
>
>
>
> --
> Filipe David Manana,
> fdmanana@gmail.com, fdmanana@apache.org
>
> "Reasonable men adapt themselves to the world.
>  Unreasonable men adapt the world to themselves.
>  That's why all progress depends on unreasonable men."
>

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