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 <j...@iriscouch.com> wrote: > Sorry, just catching up. > > +1 > > On Fri, May 10, 2013 at 4:29 PM, Jan Lehnardt <j...@apache.org> wrote: >> +1 >> >> Jan >> -- >> >> On May 7, 2013, at 21:34 , Robert Newson <rnew...@apache.org> wrote: >> >>> Hi All, >>> >>> I propose to merge in the following work, >>> https://github.com/rnewson/couchdb/tree/nebraska-merge-candidate to >>> 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
