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From Joan Touzet <>
Subject [ANNOUNCE] Apache CouchDB 2.1.0 released
Date Mon, 07 Aug 2017 18:09:26 GMT
Dear community,

Apache CouchDB %VERSION% has been released and is available for

CouchDB is a database that completely embraces the web. Store your data
with JSON documents. Access your documents with your web browser, via
HTTP. Query, combine, and transform your documents with JavaScript.
CouchDB works well with modern web and mobile apps. You can distribute
your data, efficiently using CouchDB’s incremental replication. CouchDB
supports master-master setups with automatic conflict detection.

CouchDB comes with a suite of features, such as on-the-fly document
transformation and real-time change notifications, that make web
development a breeze. It even comes with an easy to use web
administration console, served directly out of CouchDB! We care a lot
about distributed scaling. CouchDB is highly available and partition
tolerant, but is also eventually consistent. And we care a lot about
your data. CouchDB has a fault-tolerant storage engine that puts the
safety of your data first.

Download your copy here:

Pre-built convenience binaries for Windows, macOS, Debian/Ubuntu and
RHEL/CentOS are available.

CouchDB 2.1.0 is a feature release, and was originally published on

The community would like to thank all contributors for their part in
making this release, from the smallest bug report or patch to major
contributions in code, design, or marketing, we couldn’t have done it
without you!

The release notes follow. A formatted version of them can be viewed

On behalf of the CouchDB PMC,
Joan Touzet


Version 2.1.0

    The Mango _find endpoint supports a new combination operator, $allMatch, which matches
and returns all documents that contain an array field with all its elements matching all the
specified query criteria.

    New scheduling replicator. The core of the new replicator is a scheduler which allows
running a large number of replication jobs by switching between them, stopping some and starting
others periodically. Jobs which fail are backed off exponentially. There is also an improved
inspection and querying API: _scheduler/jobs and _scheduler/docs:
        _scheduler/jobs : This endpoint shows active replication jobs. These are jobs managed
by the scheduler. Some of them might be running, some might be waiting to run, or backed off
(penalized) because they crashed too many times. Semantically this is somewhat equivalent
to _active_tasks but focuses only on replications. Jobs which have completed or which were
never created because of malformed replication documents will not be shown here as they are
not managed by the scheduler. _replicate replications, started form _replicate endpoint not
from a document in a _replicator db, will also show up here.
        _scheduler/docs : This endpoint is an improvement on having to go back and read replication
documents to query their state. It represents the state of all the replications started from
documents in _replicator db. Unlike _scheduler/jobs it will also show jobs which have failed
or have completed.

    By default, scheduling replicator will not update documents with transient states like
triggered or error anymore, instead _scheduler/docs API should be used to query replication
document states.

Other scheduling replicator improvements

        Network resource usage and performance was improved by implementing a shared connection
pool. This should help in cases of a large number of connections to the same sources or target.
Previously connection pools were shared only withing a single replication job.
        Improved request rate limit handling. Replicator requests will auto-discover rate
limit capacity on targets and sources based on a proven Additive Increase / Multiplicative
Decrease feedback control algorithm.
        Improved performance by having exponential backoff for all replication jobs failures.
Previously there were some scenarios were failure led to continuous repeated retries, consuming
CPU and disk resources in the process.
        Improved recovery from long but temporary network failure. Currently if replications
jobs fail to start 10 times in a row, they will not be retried anymore. This is sometimes
desirable, but in some cases, for example, after a sustained DNS failure which eventually
recovers, replications reach their retry limit, stop retrying and never recover. Previously
it required user intervention to continue. Scheduling replicator will never give up retrying
a valid scheduled replication job and so it should recover automatically.
        Better handling of filtered replications. Failing user filter code fetches from the
source will not block replicator manager and stall other replications. Failing filter fetches
will also be backed off exponentially. Another improvement is when filter code changes on
the source, a running replication will detect that and restart itself with a new replication
ID automatically.

The 2.1.0 release also includes the following minor improvements:

    COUCHDB-1946: Hibernate couch_stream after each write (up to 70% reduction in memory usage
during replication of DBs with large attachments)
    COUCHDB-2964: Investigate switching replicator manager change feeds to using “normal”
instead of “longpoll”
    COUCHDB-2988: (mango) Allow query selector as changes and replication filter
    COUCHDB-2992: Add additional support for document size
    COUCHDB-3046: Improve reduce function overflow protection
    COUCHDB-3061: Use vectored reads to search for buried headers in .couch files. “On a
modern linux system with SSD, we see improvements up to 15x.”
    COUCHDB-3063: “stale=ok” option replaced with new “stable” and “update” options.
    COUCHDB-3180: Add features list in the welcome message
    COUCHDB-3203: Make auth handlers configurable (in ini files)
    COUCHDB-3234: Track open shard timeouts with a counter instead of logging
    COUCHDB-3242: Make get view group info timeout in couch_indexer configurable
    COUCHDB-3249: Add config to disable index all fields (text indexes)
    COUCHDB-3251: Remove hot loop usage of filename:rootname/1
    COUCHDB-3284: 8Kb read-ahead in couch_file causes extra IO and binary memory usage
    COUCHDB-3298: Optimize writing btree nodes
    COUCHDB-3302: (Improve) Attachment replication over low bandwidth network connections
    COUCHDB-3307: Limit calls to maybe_add_sys_db_callbacks to once per db open
    COUCHDB-3318: bypass couch_httpd_vhost if there are none
    COUCHDB-3323: Idle dbs cause excessive overhead
    COUCHDB-3324: Introduce couch_replicator_scheduler
    COUCHDB-3337: End-point _local_docs doesn’t conform to query params of _all_docs
    COUCHDB-3358: (mango) Use efficient set storage for field names
    COUCHDB-3425: Make _doc_ids _changes filter fast-path limit configurable
    #457: TeX/LaTeX/texinfo removed from default docs build chain
    #469: (mango) Choose index based on fields match
    #483: couchup database migration tool
    #582: Add X-Frame-Options support to help protect against clickjacking
    #593: Allow bind address of in _cluster_setup for single nodes
    #624: Enable compaction daemon by default
    #626: Allow enable node decom using string “true”
    (mango) Configurable default limit, defaults to 25.
    (mango) _design documents ignored when querying _all_docs
    (mango) add $allMatch selector
    Add local.d/default.d directories by default and document
    Improved INSTALL.* text files

Fixed Issues

The 2.1.0 release includes fixes for the following issues:

    COUCHDB-1447: X-Couch-Update-NewRev header is missed if custom headers are specified in
response of _update handler (missed in 2.0 merge)
    COUCHDB-2731: Authentication DB was not considered a system DB
    COUCHDB-3010: (Superceded fix for replication exponential backoff)
    COUCHDB-3090: Error when handling empty “Access-Control-Request-Headers” header
    COUCHDB-3100: Fix documentation on require_valid_user
    COUCHDB-3109: 500 when include_docs=true for linked documents
    COUCHDB-3113: fabric:open_revs can return {ok, []}
    COUCHDB-3149: Exception written to the log if db deleted while there is a change feed
    COUCHDB-3150: Update all shards with stale=update_after
    COUCHDB-3158: Fix a crash when connection closes for _update
    COUCHDB-3162: Default ssl settings cause a crash
    COUCHDB-3164: Request fails when using _changes?feed=eventsource&heartbeat=30000
    COUCHDB-3168: Replicator doesn’t handle well writing documents to a target db which
has a small max_document_size
    COUCHDB-3173: Views return corrupt data for text fields containing non-BMP characters
    COUCHDB-3174: max_document_size setting can by bypassed by issuing multipart/related requests
    COUCHDB-3178: Fabric does not send message when filtering lots of documents
    COUCHDB-3181: function_clause error when adding attachment to doc in _users db
    COUCHDB-3184: couch_mrview_compactor:recompact/1 does not handle errors in spawned process
    COUCHDB-3193: fabric:open_revs returns multiple results when one of the shards has stem_interactive_updates=false
    COUCHDB-3199: Replicator VDU function doesn’t acount for an already malformed document
in replicator db
    COUCHDB-3202: (mango) do not allow empty field names
    COUCHDB-3220: Handle timeout in _revs_diff
    COUCHDB-3222: (Fix) HTTP code 500 instead of 400 for invalid key during document creation
    COUCHDB-3231: Allow fixing users’ documents (type and roles)
    COUCHDB-3232: user context not passed down in fabric_view_all_docs
    COUCHDB-3238: os_process_limit documentation wrong
    COUCHDB-3241: race condition in couch_server if delete msg for a db is received before
open_result msg
    COUCHDB-3245: Make couchjs -S option take effect again
    COUCHDB-3252: Include main-coffee.js in release artifact (broken CoffeeScript view server)
    COUCHDB-3255: Conflicts introduced by recreating docs with attachments
    COUCHDB-3259: Don’t trap exits in couch_file
    COUCHDB-3264: POST to _all_docs does not respect conflicts=true
    COUCHDB-3269: view response can ‘hang’ with filter and limit specified
    COUCHDB-3271: Replications crash with ‘kaboom’ exit
    COUCHDB-3274: eof in couch_file can be incorrect after error
    COUCHDB-3277: Replication manager crashes when it finds _replicator db shards which are
not part of a mem3 db
    COUCHDB-3286: Validation function throwing unexpected json crashes with function_clause
    COUCHDB-3289: handle error clause when calling fabric:open_revs
    COUCHDB-3291: Excessively long document IDs prevent replicator from making progress
    COUCHDB-3293: Allow limiting length of document ID (for CouchDB proper)
    COUCHDB-3305: (mango) don’t crash with invalid input to built in reducer function
    COUCHDB-3362: DELETE attachment on non-existing document creates the document, rather
than returning 404
    COUCHDB-3364: Don’t crash compactor when compacting process fails.
    COUCHDB-3367: Require server admin user for db/_compact and db_view_cleanup endpoints
    COUCHDB-3376: Fix mem3_shards under load
    COUCHDB-3378: Fix mango full text detection
    COUCHDB-3379: Fix couch_auth_cache reinitialization logic
    COUCHDB-3400: Notify couch_index_processes on all shards when ddoc updated
    COUCHDB-3402: race condition in mem3 startup
    #511: (mango)  Return false for empty list
    #595: Return 409 to PUT attachment with non-existent rev
    #623: Ensure replicator _active_tasks entry reports recent pending changes value
    #627: Pass UserCtx to fabric’s all_docs from mango query
    #631: fix couchdb_os_proc_pool eunit timeouts
    #644: Make couch_event_sup:stop/1 synchronous
    #645: Pass db open options to fabric_view_map for _view and _list queries on _users DB
    #648: Fix couch_replicator_changes_reader:process_change
    #649: Avoid a race when restarting an index updater
    #667: Prevent a terrible race condition
    #677: Make replication filter fetch error for _replicate return a 404
    Fix CORS max_age configuration parameter via Access-Control-Max-Age
    Chunk missing revisions before attempting to save on target (improves replication for
very conflicted, very deep revision tree documents)
    Allow w parameter for attachments
    Return “Bad Request” when count in /_uuids exceeds max
    Fix crashes when replicator db is deleted
    Skip internal replication if changes already replicated
    Fix encoding issues on _update/../doc_id and PUT attachments

Upgrade Notes

    The deprecated (and broken) OAuth 1.0 implementation has been removed.
    If user code reads or manipulates replicator document states, consider using the [replicator]
update_docs = true compatibility parameter. In that case replicator will continue updating
documents with transient replication states. However, that will incure a performance cost.
Consider instead switching using _scheduler/docs HTTP endpoint.
    The stale parameter for views and _find has been deprecated in favour of two new parameters:
stable and update. The old stale=ok behaviour is equivalent to stable=true&update=false,
and the old stale=update_after behaviour is equivalent to stable=true&update=lazy. The
deprecated stale parameter will be removed in CouchDB 3.0.
    The [couchdb] max_document_size configuration parameter was renamed to [httpd] max_http_request_size
to reflect its actual implementation. It has been enhanced by a new [couchdb] single_max_doc_size
setting. Both are documented in the shipped default.ini file.

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