paranoid check and verify checksum configuration for levelDB

classic Classic list List threaded Threaded
9 messages Options
Reply | Threaded
Open this post in threaded view
|

paranoid check and verify checksum configuration for levelDB

Steven Turner
Hi,

I have gone through http://activemq.apache.org/leveldb-store.html.
What is paranoid check and difference between paranoid check and verify checksum ? What is the overhead of enabling these configuration ?


Thanks,
Steven
Reply | Threaded
Open this post in threaded view
|

Re: paranoid check and verify checksum configuration for levelDB

Steven Turner
Really confuse between both the parameters. Can someone help me here ?
Reply | Threaded
Open this post in threaded view
|

Re: paranoid check and verify checksum configuration for levelDB

Tim Bain
Anuj,

You should probably post questions that are purely about LevelDB to the
LevelDB mailing list.  If you're confused about how ActiveMQ uses LevelDB,
then this list could be a good source of information, but most of the
questions you've asked about LevelDB recently are about its inner workings
and would be much better answered by people who know LevelDB more
intimately than the people on this list.

Tim

On Wed, Nov 5, 2014 at 5:40 AM, Steven Turner <[hidden email]>
wrote:

> Really confuse between both the parameters. Can someone help me here ?
>
>
>
> --
> View this message in context:
> http://activemq.2283324.n4.nabble.com/paranoid-check-and-verify-checksum-configuration-for-levelDB-tp4686923p4686956.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>
Reply | Threaded
Open this post in threaded view
|

Re: paranoid check and verify checksum configuration for levelDB

Steven Turner
Tim,

How come "paranoid check and verify checksum " parameters are related to leveldb and not activemq. These parameters are mentioned http://activemq.apache.org/leveldb-store.html but only with one line. No detailed documentation is provided. Same with all other parameters. If we want to explore a new feature in ActiveMQ, we are supposed to know internal details.
ActiveMQ should have detailed documentation about leveldb. That's why we are asking here questions.

Reply | Threaded
Open this post in threaded view
|

Re: paranoid check and verify checksum configuration for levelDB

khandelwalanuj
In reply to this post by Tim Bain
There is no detailed documentation for Activemq. I already asked here http://activemq.2283324.n4.nabble.com/LevelDB-Documentation-td4679547.html#a4686768 
but nobody comes back. I have asked around 5,6 questions about levledb and it's been 5 days. But not even a single ActiveMQ vendor is replying. We are users of Amq who wants to go into details before using it, and this is the only place we can ask if we have some confusion. Amq Gods should give some better response.
Reply | Threaded
Open this post in threaded view
|

Re: paranoid check and verify checksum configuration for levelDB

khandelwalanuj
In reply to this post by Tim Bain
Reply | Threaded
Open this post in threaded view
|

Re: paranoid check and verify checksum configuration for levelDB

Tim Bain
I said that those options are related to LevelDB and not ActiveMQ because,
very simply, they're features of LevelDB; for example, you can see both
variables in the LevelDB API at
https://github.com/dain/leveldb/blob/master/leveldb-api/src/main/java/org/iq80/leveldb/Options.java,
which was the second search result in Google when I searched for  '
"paranoidChecks" LevelDB'.  These are features of LevelDB, implemented by
the developers of LevelDB, and best understood by the developers of
LevelDB, which is why I suggested that you'd get better answers from the
people who developed LevelDB than from the people who simply chose to use
it.  After all, you're frustrated because you're not getting answers to
your LevelDB questions on this list, right?  Maybe it's because this list
isn't the one where all the people who know LevelDB well hang out...

Of the four questions you linked to:

   - #1 is about when LevelDB does garbage collection of its log files,
   which are a LevelDB core feature and not an ActiveMQ addition.
   - #2 is about whether you can safely copy LevelDB's internal data files
   (which are a LevelDB core feature and not an ActiveMQ addition) from one
   instance to another, and whether the new instance will be able to use them
   to populate the database; although there's a portion of the question that's
   whether ActiveMQ will handle a copied database correctly if LevelDB is able
   to load it in the first place, there's a large part of the question that's
   simply when you can safely assume that LevelDB is finished writing its
   files and whether a new database will read them properly, which are a
   LevelDB core feature and not an ActiveMQ addition.
   - #3 is primarily a question about the claims made by the ActiveMQ
   documentation, so it's a reasonable question for this list.
   - #4 is a question about the default compression values used by LevelDB,
   which are a LevelDB core feature and not an ActiveMQ addition.

Your statement that "all of them are related to ActiveMQ using leveldb.
None is related to core leveldb features" isn't accurate; although a some
portions of your questions are related to how ActiveMQ uses LevelDB, the
meat of most of them is really about LevelDB's inner workings, and I think
you're more likely to get those answers on the LevelDB list.

Also, you seem to be confused about what ActiveMQ is, so let's be clear:
ActiveMQ is an open-source project, whose code, documentation, and support
via this mailing list are all written by volunteers like you and me, who
donate their time to help others.  The people on this mailing lists aren't
vendors (or if they are, I feel pretty confident guessing that you haven't
paid them for a support contract), so any help anyone gives is because they
choose to spend their free time helping you instead of any of the other
things they could do with their free time.  If you ask a question and
someone knows the answer and wants to help, then great; if not, then look
for answers in other places (which is why I've pointed you to the LevelDB
mailing list), go pay for a support contract with a company who you can
hold accountable for not responding to your questions after 5 days, or grab
the source code - since this is an open-source project and it's all freely
available - and figure it out yourself and then improve the documentation
for the next person.

Tim

On Wed, Nov 5, 2014 at 10:34 PM, khandelwalanuj <[hidden email]
> wrote:
Reply | Threaded
Open this post in threaded view
|

Re: paranoid check and verify checksum configuration for levelDB

khandelwalanuj
This post was updated on .
As you mentioned:

- #4 is a question about the default compression values used by LevelDB,
   which are a LevelDB core feature and not an ActiveMQ addition.

I am checking the source code of ActiveMQ and commits made as part of leveldb changes: I can clearly sees that compaction ratio and other parameters are modified according to the use-case. As you can see here:
http://activemq.2283324.n4.nabble.com/svn-commit-r1481528-in-activemq-trunk-activemq-leveldb-store-src-main-scala-org-apache-activemq-levea-td4666939.html

and

http://mail-archives.apache.org/mod_mbox/activemq-commits/201302.mbox/%3CJIRA.12631390.1360306074585.317546.1361457973221@arcas%3E 


Reply | Threaded
Open this post in threaded view
|

Re: paranoid check and verify checksum configuration for levelDB

Tim Bain
I apologize, it sounds like I steered you astray on that particular
question.  Hopefully either someone on the mailing list like Hiram will be
able to answer your question, or you'll learn the answer as you look
through the source and post the answer back here for the next person who
has the question.

On Mon, Nov 10, 2014 at 8:18 AM, khandelwalanuj <[hidden email]
> wrote:

> As you mentioned:
>
> - #4 is a question about the default compression values used by LevelDB,
>    which are a LevelDB core feature and not an ActiveMQ addition.
>
> I am checking the source code of ActiveMQ and commits made as part of
> leveldb changes: I can clearly sees that compaction ratio and other
> parameters are modified according to the use-case. As you can see here:
>
> http://mail-archives.apache.org/mod_mbox/activemq-commits/201302.mbox/%3CJIRA.12631390.1360306074585.317546.1361457973221@arcas%3E
>
>
>
>
>
>
> --
> View this message in context:
> http://activemq.2283324.n4.nabble.com/paranoid-check-and-verify-checksum-configuration-for-levelDB-tp4686923p4687093.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>