Righto. Now to remember how subversion works...

On 15 May 2013 17:09, Noah Slater <[email protected]> wrote:
> Okay.
>
> Start here:
>
> http://incubator.apache.org/ip-clearance/
>
> Then make a copy of this file:
>
> http://svn.apache.org/repos/asf/incubator/public/trunk/content/ip-clearance/ip-clearance-template.xml
>
> This file, when rendered to HTML will look like:
>
> http://incubator.apache.org/ip-clearance/ip-clearance-template.html
>
> In your local copy, cut everything from:
>
>       <pre>-----8-&lt;---- cut here -------8-&lt;---- cut here
> -------8-&lt;---- cut here-------8-&lt;----</pre>
>
> To:
>
>       <pre>-----8-&lt;---- cut here -------8-&lt;---- cut here
> -------8-&lt;---- cut here-------8-&lt;----</pre>
>
> Now, add your copy back to Subversion here:
>
> http://svn.apache.org/repos/asf/incubator/public/trunk/content/ip-clearance/
>
> Call it "couchdb-bigcouch.xml".
>
> In a few minutes, this will appear here:
>
> http://incubator.apache.org/ip-clearance/couchdb-bigcouch.html
>
> Now, it should be a simple matter of going through the doc and completing
> the checkpoints/sections.
>
> Here are the two previous ones we've done:
>
> http://incubator.apache.org/ip-clearance/couchdb-docs.html
>
> http://incubator.apache.org/ip-clearance/couchdb-fauxton.html
>
> Let me know if you get stuck on any of the checkpoints.
>
> Once you're done, let me know, and I will use my member karma to push it
> through the Incubator.
>
> Benoit, you may as well start your rcouch stuff at the same time using this
> instructions. Obviously, you should pick "couchdb-rcouch.xml" instead. But
> other than that, it's the same process.
>
> On 15 May 2013 16:24, Noah Slater <[email protected]> wrote:
>
>> I can help! :)
>>
>>
>> On 15 May 2013 16:23, Robert Newson <[email protected]> wrote:
>>
>>> :)
>>>
>>> Jan, I think you said you'd help start the IP clearance bit?
>>>
>>> On 15 May 2013 15:03, Noah Slater <[email protected]> wrote:
>>> > PARTY TIME 🎉
>>> >
>>> >
>>> > On 15 May 2013 10:40, Robert Newson <[email protected]> wrote:
>>> >
>>> >> Thanks everyone.
>>> >>
>>> >> The tally is;
>>> >>
>>> >> 13 +1's
>>> >>
>>> >> The vote passes. We'll now move on to IP clearance. Once that's done
>>> >> the work will arrive on a feature branch in our main git repository.
>>> >>
>>> >> B.
>>> >>
>>> >>
>>> >> On 13 May 2013 04:31, Jason Smith <[email protected]> wrote:
>>> >> > Sorry, just catching up.
>>> >> >
>>> >> > +1
>>> >> >
>>> >> > On Fri, May 10, 2013 at 4:29 PM, Jan Lehnardt <[email protected]>
>>> wrote:
>>> >> >> +1
>>> >> >>
>>> >> >> Jan
>>> >> >> --
>>> >> >>
>>> >> >> On May 7, 2013, at 21:34 , Robert Newson <[email protected]>
>>> wrote:
>>> >> >>
>>> >> >>> Hi All,
>>> >> >>>
>>> >> >>> I propose to merge in the following work,
>>> >> >>> https://github.com/rnewson/couchdb/tree/nebraska-merge-candidateto
>>> >> >>> the official Apache CouchDB repository to a new branch (i.e, *not*
>>> >> >>> master). Once there, the full CouchDB developer community can begin
>>> >> >>> the work to incorporate the code here into an official release.
>>> >> >>>
>>> >> >>> You do not need to respond if you are in agreement. If there is no
>>> >> >>> response in 72 hours, I will assume lazy consensus. If we reach
>>> >> >>> consensus, I will start the IP clearance process and then the
>>> merge.
>>> >> >>>
>>> >> >>> As most of you know, Paul Davis and I recently sequestered
>>> ourselves
>>> >> >>> away from society (in a place called Nebraska) to make this merge
>>> >> >>> happen. I want to clarify that this work is not the BigCouch code
>>> you
>>> >> >>> can see on github.com/cloudant/bigcouch but the Cloudant platform
>>> from
>>> >> >>> which BigCouch was made. This means it is bang up to date with all
>>> the
>>> >> >>> bug fixes and feature enhancements we've made in the last eighteen
>>> >> >>> months or more. With that clarification made, here are our notes
>>> about
>>> >> >>> what we achieved, what it means to the project and what isn't yet
>>> >> >>> done;
>>> >> >>>
>>> >> >>> Nebraska Merge Roundup
>>> >> >>>
>>> >> >>>
>>> >> >>> Stats:
>>> >> >>>
>>> >> >>>
>>> >> >>> 1402 - total new commits
>>> >> >>>
>>> >> >>> 312 - commits written during the merge (will be reduced
>>> substantially
>>> >> >>> by squashing)
>>> >> >>>
>>> >> >>> 408 - number of files changed
>>> >> >>>
>>> >> >>> 21,897 - number of lines added
>>> >> >>>
>>> >> >>> 4,277 - number of lines removed
>>> >> >>>
>>> >> >>> A retrospective:
>>> >> >>>
>>> >> >>> Bob Newson and I have come to the end of our merge sprint on
>>> getting
>>> >> >>> BigCouch merged into Apache CouchDB. Its been a productive ten days
>>> >> >>> here in the midwest. I managed to get Bob out to a bowling alley
>>> and
>>> >> >>> he managed to get me to a sushi restaurant. In between the cultural
>>> >> >>> exchanges we’ve also managed to get a significant amount of work
>>> done
>>> >> >>> on the merging as well.
>>> >> >>>
>>> >> >>>
>>> >> >>> The current status of the merge is that we’ve managed to resolve
>>> the
>>> >> >>> differences in the single node execution of CouchDB. Both the
>>> >> >>> JavaScript and Erlang test suites run with only one failure in the
>>> >> >>> Erlang test suite due to a (deliberately) missing constraint on the
>>> >> >>> number of operating system processes. This should be a relatively
>>> >> >>> straightforward fix but was not prioritized during our limited
>>> time to
>>> >> >>> work on the larger issues.
>>> >> >>>
>>> >> >>>
>>> >> >>> We merged a large number of performance and stability enhancements
>>> >> >>> back into single node CouchDB as well as a number of pure bug
>>> fixes.
>>> >> >>> The biggest highlight is a brand new compactor that is both faster
>>> and
>>> >> >>> creates smaller and better organized post-compaction databases.
>>> >> >>>
>>> >> >>>
>>> >> >>> The current status of the merge is that single node operations
>>> should
>>> >> >>> be completely unaffected as demonstrated by the test suite
>>> passing. On
>>> >> >>> the other hand we haven’t yet finished getting the clustered code
>>> >> >>> merged to use some of the new changes in single node CouchDB. The
>>> >> >>> single most significant portion of this work involves updates to
>>> the
>>> >> >>> internal cluster API for views to use the recently rewritten
>>> indexer
>>> >> >>> APIs. This should be a relatively straightforward bit of work that
>>> >> >>> we’ll be finishing over the next few weeks.
>>> >> >>>
>>> >> >>>
>>> >> >>> All in all the merge work done so far has been quite successful.
>>> We’ve
>>> >> >>> met our primary goal of getting the code merged in a fashion that
>>> does
>>> >> >>> not affect single node operation while providing a starting point
>>> for
>>> >> >>> the larger community to start reviewing the more significant
>>> changes
>>> >> >>> made. Given the size of the diff between the two code bases we
>>> never
>>> >> >>> expected to have a fully working clustered solution after ten days
>>> of
>>> >> >>> work but we have succeeded in providing a base of work that will
>>> allow
>>> >> >>> us and new contributors to get up to speed quickly.
>>> >> >>>
>>> >> >>>
>>> >> >>> This work, coupled with work by Dave Cottlehuber and Benoît
>>> Chesneau
>>> >> >>> on updating the build system and various other internal updates,
>>> will
>>> >> >>> provide a solid foundation for work going forward. Its an exciting
>>> >> >>> time for CouchDB and anyone interested should keep an eye on the
>>> next
>>> >> >>> few releases as we ramp up work on various core aspects of the
>>> >> >>> database.
>>> >> >>>
>>> >> >>>
>>> >> >>> We’ve had an exciting few days working to prepare the road for an
>>> >> >>> exciting next twelve to eighteen months. We hope that everyone will
>>> >> >>> feel as excited as we do about the next twelve to eighteen months
>>> for
>>> >> >>> Apache CouchDB. It should be an exciting ride.
>>> >> >>>
>>> >> >>>
>>> >> >>>
>>> >> >>> Things we got done
>>> >> >>>
>>> >> >>>
>>> >> >>> * Large update to the source tree layout for Erlang applications.
>>> Each
>>> >> >>> application now has a src/appname/(c_src|ebin|priv|src) structure.
>>> The
>>> >> >>> build system has been updated.
>>> >> >>>
>>> >> >>> * Renamed src/couchdb to src/couch to match the Erlang convention
>>> of
>>> >> >>> the top directory name matching the Erlang application name.
>>> >> >>>
>>> >> >>> * Imported Cloudant Erlang applications for clustered CouchDB.
>>> These
>>> >> >>> are imported with their history by using git subtree and merging
>>> the
>>> >> >>> top level commit. These are not external deps, development will
>>> happen
>>> >> >>> within the CouchDB tree. The imported apps are:
>>> >> >>>
>>> >> >>>
>>> >> >>>   * config - A couch_config replacement (Behavior is mostly
>>> identical
>>> >> >>> to couch_config except how we listen for configuration changes
>>> >> >>> internally to allow for smooth hot code upgrade).
>>> >> >>>
>>> >> >>>   * twig - An rsyslog source replacement for couch_log.
>>> >> >>>
>>> >> >>>   * rexi - An RPC library. Replaces Erlang’s built-in rex
>>> application
>>> >> >>> to avoid costly safety measures in the interest of performance and
>>> >> >>> throughput.
>>> >> >>>
>>> >> >>>   * mem3 - The “Dynamo” part of BigCouch responsible for managing
>>> >> cluster state
>>> >> >>>
>>> >> >>>   * fabric - The internal cluster-aware CouachDB API
>>> >> >>>
>>> >> >>>   * ets_lru - A small library application that provides an LRU
>>> >> >>> implementation using a couple ets tables.
>>> >> >>>
>>> >> >>>   * ddoc_cache - Caches design documents on each node for use in
>>> >> >>> design handler functions. This uses an ets_lru cache with a very
>>> short
>>> >> >>> TTL.
>>> >> >>>
>>> >> >>>   * chttpd - The cluster aware HTTP layer
>>> >> >>>
>>> >> >>>
>>> >> >>> Each imported app also had its build system updated to use
>>> Autotools
>>> >> >>> along with the necessary updates noted above for the new
>>> application
>>> >> >>> layouts for existing CouchDB erlang apps.
>>> >> >>>
>>> >> >>>
>>> >> >>> * Merged a large amount of updates and fixes to couch_replicator
>>> based
>>> >> >>> on work done internally at Cloudant. Unfortunately due to an error
>>> >> >>> when we created our internal clone we lost a bit of history in
>>> some of
>>> >> >>> the initial merge and have a big commit that affects
>>> >> >>> couch_replicator_manager mostly. There are a number of other
>>> commits
>>> >> >>> related to couch_replicator that resolve the single node vs.
>>> clustered
>>> >> >>> differences. Some noticeable couch_replicator features:
>>> >> >>>
>>> >> >>>
>>> >> >>>   * Optionally disable checkpoints so that replication can work
>>> when
>>> >> >>> a source is read only. This should only be used for smaller
>>> databases
>>> >> >>> as each replication call has to scan the entire source database on
>>> >> >>> each invocation.
>>> >> >>>
>>> >> >>>   * A new changes_pending field in the _active_tasks output
>>> >> >>>
>>> >> >>>   * A fix to the continuous replication to automatically reconnect
>>> to
>>> >> >>> a continuous changes feed when it sees a last_seq value. This
>>> allows
>>> >> >>> for the source to selectively recycle the HTTP connections used
>>> which
>>> >> >>> can be quite useful for “permanent” replications.
>>> >> >>>
>>> >> >>>   * A multitude of smaller bug fix and stability enhancements.
>>> >> >>>
>>> >> >>>
>>> >> >>> Updates to single node couch:
>>> >> >>>
>>> >> >>>
>>> >> >>> * We changed the by_seq tree to store a copy of the
>>> #full_doc_info{}
>>> >> >>> record instead of the #doc_info{} record. This gives significant
>>> speed
>>> >> >>> improvements for compaction and replication and generally anything
>>> >> >>> that needs to walk the by_seq tree and access document bodies
>>> >> >>> internally.
>>> >> >>>
>>> >> >>> * We rewrote the compactor to be significantly faster as well as
>>> >> >>> provides significantly better compacted databases. The two main
>>> halves
>>> >> >>> are to use a temp file and replace the use of btrees in the temp
>>> file.
>>> >> >>> The temp file only contains a temporary copy of the document ids.
>>> At
>>> >> >>> the end of a compaction run we then rebuild the by_id btree in the
>>> >> >>> compaction file from this temp file. The reason this helps so much
>>> is
>>> >> >>> that the compaction is based on the update_seq btree, which for
>>> most
>>> >> >>> cases means that the id tree is updated in roughly random order
>>> which
>>> >> >>> is very bad for our append only btrees. By using the tmp file we
>>> can
>>> >> >>> stream it in order back into the compacted db file at the end of
>>> >> >>> compacting, generating a minimum amount of garbage in the process.
>>> The
>>> >> >>> other upgrade was to implement an external merge sort module
>>> >> >>> (couch_emsort) that is used with this temporary file.
>>> >> >>>
>>> >> >>> * Reject updates to design docs that introduce updates that break
>>> >> >>> compilation for source code. Currently we only check map and reduce
>>> >> >>> calls as the other should provide user visible errors instead of
>>> >> >>> inexplicably empty views.
>>> >> >>>
>>> >> >>> because my OCD kicked in and I was unable to resist.
>>> >> >>>
>>> >> >>> * Reverted a change made a long time ago that uses two file
>>> >> >>> descriptors for each database. See the todo list.
>>> >> >>>
>>> >> >>> * The reason to remove the second fd is so that we can rewrite ref
>>> >> >>> counting. Better ref counting makes everyone happy, but the real
>>> >> >>> reason is for this next bullet point:
>>> >> >>>
>>> >> >>> * Optimize couch_server to not require a round trip message pass
>>> for
>>> >> >>> opening a database that’s in the LRU. This is a significant
>>> >> >>> performance boost for high concurrency access. We also optimized
>>> >> >>> couch_server internals to not blow up when it’s under load.
>>> >> >>>
>>> >> >>> * Introduce a #leaf{} record into the revision trees. This is never
>>> >> >>> written to disk but makes internal code a lot cleaner when dealing
>>> >> >>> with multiple versions of rev tree values.
>>> >> >>>
>>> >> >>> * Some changes to couch_changes to enable clustered access. Also
>>> some
>>> >> >>> general cleanup
>>> >> >>>
>>> >> >>> * Internal changes to how CouchDB is booted in Erlang land. Not
>>> very
>>> >> >>> sexy but this removes a lot of complicated un-Erlangy bits. We
>>> still
>>> >> >>> have a bit of work left here.
>>> >> >>>
>>> >> >>> * btree chunk sizes are now configurable which can allow people to
>>> >> >>> adjust the RAM/speed tradeoffs a bit more.
>>> >> >>>
>>> >> >>> * We now load update validation functions on the first write. This
>>> is
>>> >> >>> a cluster-motivated change because the clustered version of this
>>> call
>>> >> >>> is expensive and can lead to race conditions when opening a bunch
>>> of
>>> >> >>> db shards simultaneously. This should be invisible to external
>>> >> >>> clients.
>>> >> >>>
>>> >> >>> * Disabled conflict detection for local docs. They don’t replicate
>>> so
>>> >> >>> there’s no point. This just led to clusters getting stuck and
>>> confused
>>> >> >>> when there were lots of replications happening.
>>> >> >>>
>>> >> >>> * Changes to the multipart/mime parsing code. Necessary for
>>> clustered
>>> >> >>> attachment uploads to split the incoming data  stream into N
>>> copies.
>>> >> >>>
>>> >> >>> * Don’t use init:restart/0 when reloading the ICU driver. I think
>>> >> >>> this has a bug. But we should rewrite this driver to be a NIF
>>> anyway.
>>> >> >>>
>>> >> >>> * New couch OS process manager. Significantly faster access to OS
>>> >> >>> processes under heavy load. This replaces the hard limit with a
>>> soft
>>> >> >>> limit. Process spawned over the soft limit will be used until
>>> they’ve
>>> >> >>> sat idle for a few minutes and then be closed. We have a todo item
>>> to
>>> >> >>> add the hard ceiling back in (while keeping the soft ceiling).
>>> >> >>>
>>> >> >>> * Automatically replace some easily identifiable JS reductions with
>>> >> >>> their builtin counterparts. Uses a regex to do the detection so its
>>> >> >>> not too smart.
>>> >> >>>
>>> >> >>> * Improved view updater write batch.
>>> >> >>>
>>> >> >>> * Updates to couchjs’ views.js to improve index update speeds
>>> >> >>>
>>> >> >>> * Updates to the _stats bultin reduce to allow reduces to work over
>>> >> >>> emitted stats objects. Sometimes clients have summary data in a
>>> doc,
>>> >> >>> and this allows them to combine stats if they follow the same
>>> pattern
>>> >> >>> as the builtin expects.
>>> >> >>>
>>> >> >>> * Added a config:reload() that is accessible by POST’ing to
>>> >> >>> _config/_reload. Used by the JS tests to reset the config to
>>> what's on
>>> >> >>> disk. This should prevent those test run failures where a test
>>> fails
>>> >> >>> leaving the config in a bad state causing all subsequent tests to
>>> >> >>> fail. I think. Maybe.
>>> >> >>>
>>> >> >>> * Databases are deleted synchronously in the test suite. We may
>>> need
>>> >> >>> to address this on Windows. But it does seem to reduce the number
>>> of
>>> >> >>> “{error, file_exists}” failures.
>>> >> >>>
>>> >> >>> * I reimplemented the JS restartServer() function. There’s a new
>>> >> >>> _restart/token URL that will given a unique value for each
>>> instance of
>>> >> >>> the Erlang VM. To run a restart we grab the current token value,
>>> hit
>>> >> >>> _restart, then wait till we get a successful response with a
>>> different
>>> >> >>> token. This appears to have made the restart strategy more robust.
>>> >> >>>
>>> >> >>>
>>> >> >>>
>>> >> >>> Things that need doing
>>> >> >>>
>>> >> >>>
>>> >> >>> IP Clearance -
>>> >> >>>
>>> >> >>>
>>> >> >>> We’ll need to track down if we have the CCLA as well as look at
>>> each
>>> >> >>> source file added to make sure each one is strictly from Cloudant
>>> or
>>> >> >>> has an amenable license. I’m pretty sure that the only one of
>>> interest
>>> >> >>> is trunc_io.erl but we need to be thorough.
>>> >> >>>
>>> >> >>> documentation -
>>> >> >>>
>>> >> >>>
>>> >> >>> There shouldn’t be much here since the entire point of this merge
>>> was
>>> >> >>> to not change the visible behavior of single node couch. A few
>>> things
>>> >> >>> to add about the testing endpoints. Maybe an update to the
>>> compaction
>>> >> >>> section mention the two new file names used.
>>> >> >>>
>>> >> >>>
>>> >> >>> Copyright notices -
>>> >> >>>
>>> >> >>>
>>> >> >>> We need to strip out copyright notices from individual files and
>>> make
>>> >> >>> sure all files have a standard Apache License v2 header.
>>> >> >>>
>>> >> >>>
>>> >> >>> clustered vhosts -
>>> >> >>>
>>> >> >>>
>>> >> >>> We’ve never implemented this at Cloudant. We either need to write a
>>> >> >>> cluster or go back and tell people to use HAProxy (or similar) for
>>> >> >>> such things.
>>> >> >>>
>>> >> >>>
>>> >> >>> twig -
>>> >> >>>
>>> >> >>>
>>> >> >>> We need to add another output type to twig that is configurable in
>>> >> >>> some manner. Right now we spit out entire rsyslog records which
>>> isn’t
>>> >> >>> useful for most people. We’ll need to implement the file writer
>>> from
>>> >> >>> couch_log as well as update the _log HTTP handler to know when it
>>> can
>>> >> >>> and can’t expect to find data on disk.
>>> >> >>>
>>> >> >>>
>>> >> >>> fabric -
>>> >> >>>
>>> >> >>>
>>> >> >>> This is going to need a lot of work. Specifically view access is
>>> going
>>> >> >>> to need to be updated to work with couch_mrview and friends.
>>> >> >>>
>>> >> >>>
>>> >> >>> Boot a dev cluster -
>>> >> >>>
>>> >> >>>
>>> >> >>> Once we fix up the clustering code we’ll need to write instructions
>>> >> >>> and scripts for pulling up a dev cluster.
>>> >> >>>
>>> >> >>>
>>> >> >>> OTP stuff -
>>> >> >>>
>>> >> >>>
>>> >> >>> We’ve updated each app but we still need to pull some parts out of
>>> >> >>> couchdb into their own application. Specifically the HTTP layer
>>> needs
>>> >> >>> its own app. We could probably pull out the os
>>> process/query_servers
>>> >> >>> as well as the os daemons and friends. Once done we need to update
>>> the
>>> >> >>> supervision trees so we don’t have things like couch starting and
>>> >> >>> managing the replication manager process.
>>> >> >>>
>>> >> >>>
>>> >> >>> ddoc_cache -
>>> >> >>>
>>> >> >>>
>>> >> >>> Wire this up in couch_httpd_db to actually be used. Right now its
>>> only
>>> >> >>> used in chttpd.
>>> >> >>>
>>> >> >>>
>>> >> >>> couch_file upgrade -
>>> >> >>>
>>> >> >>>
>>> >> >>> The revert to remove the second updater_fd from each #db{} record
>>> >> >>> means that we’re back in the original position of files appearing
>>> to
>>> >> >>> slow down significantly under load. Since the initial hammer
>>> approach
>>> >> >>> of just adding a second fd we’ve since discovered that the
>>> underlying
>>> >> >>> bug is due to the way that message passing works combined with
>>> >> >>> Erlang’s file io. Significantly though is the fact that the fix is
>>> >> >>> rather simple to implement. A first draft of this work is on an old
>>> >> >>> branch of mine here:
>>> >> >>>
>>> >> >>>
>>> >> >>>   https://github.com/davisp/couchdb/commit/d856878
>>> >> >>>
>>> >> >>>
>>> >> >>> finish the size calculating changes -
>>> >> >>>
>>> >> >>>
>>> >> >>> The #leaf{} record change is to enable us to add more data size
>>> >> >>> calculations. CouchDB master calculates a data size that account
>>> for
>>> >> >>> all bytes that are active in a .couch file. Cloudant is interested
>>> in
>>> >> >>> the total size of uncompressed docs and attachments minus the
>>> internal
>>> >> >>> overhead of btrees. And there’s a fourth number to calculate based
>>> on
>>> >> >>> the compression level used. Having each of these numbers will be
>>> >> >>> useful as well as the calculations they’ll enable (ie, dead bytes
>>> in
>>> >> >>> file, bytes used for overhead, compression ratio achieved, etc).
>>> >> >>>
>>> >> >>>
>>> >> >>> couch_proc_manager -
>>> >> >>>
>>> >> >>>
>>> >> >>> We need to implement the hard ceiling for capping the number of OS
>>> >> >>> processes. We’ve started seeing a need for this at Cloudant with
>>> some
>>> >> >>> work loads so motivation to fix this is high. The only failing
>>> etap is
>>> >> >>> the assertion of this ceiling.
>>> >> >>>
>>> >> >>>
>>> >> >>> Synchronous db delete on Windows -
>>> >> >>>
>>> >> >>>
>>> >> >>> I did this because running the test suite was driving me bonkers. I
>>> >> >>> need to ask Dave about how this behaves on Windows (my guess is not
>>> >> >>> well) but I think we can close things up so that it works better
>>> than
>>> >> >>> the status quo.
>>> >> >>
>>> >> >
>>> >> >
>>> >> >
>>> >> > --
>>> >> > Iris Couch
>>> >>
>>> >
>>> >
>>> >
>>> > --
>>> > NS
>>>
>>
>>
>>
>> --
>> NS
>>
>
>
>
> --
> NS

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