16.1. 2.3.x Branch

16.1.1. Upgrade Notes

  • #1602: To improve security, there have been major changes in the configuration of query servers, SSL support, and HTTP global handlers:

    1. Query servers

    Query servers are NO LONGER DEFINED in the .ini files, and can no longer be altered at run-time.

    The JavaScript and CoffeeScript query servers continue to be enabled by default. Setup differences have been moved from default.ini to the couchdb and couchdb.cmd start scripts respectively.

    Additional query servers can now be configured using environment variables:

    export COUCHDB_QUERY_SERVER_PYTHON="/path/to/python/query/server.py with args"
    couchdb
    

    where the last segment in the environment variable (_PYTHON) matches the usual lowercase(!) query language in the design doc language field (here, python.)

    Multiple query servers can be configured by using more environment variables.

    You can also override the default servers if you need to set command- line options (such as couchjs stack size):

    export COUCHDB_QUERY_SERVER_JAVASCRIPT="/path/to/couchjs /path/to/main.js -S <STACKSIZE>"
    couchdb
    
    1. Native Query Servers

    The mango query server continues to be enabled by default. The Erlang query server continues to be disabled by default. This change adds a [native_query_servers] enable_erlang_query_server = BOOL setting (defaults to false) to enable the Erlang query server.

    If the legacy configuration for enabling the query server is detected, that is counted as a true setting as well, so existing configurations continue to work just fine.

    1. SSL Support

    Enabling SSL support in the ini file is now easier:

    [ssl]
    enable = true
    

    If the legacy httpsd configuration is found in your ini file, this will still enable SSL support, so existing configurations do not need to be changed.

    1. HTTP global handlers

    These are no longer defined in the default.ini file, but have been moved to the couch.app context. If you need to customize your handlers, you can modify the app context using a couchdb.config file as usual.

  • #1602: Also to improve security, the deprecated os_daemons and couch_httpd_proxy functionality has been completely removed ahead of the planned CouchDB 3.0 release. We recommend the use of OS-level daemons such as runit, sysvinit, systemd, upstart, etc. to launch and maintain OS daemons instead, and the use of a reverse proxy server in front of CouchDB (such as haproxy) to proxy access to other services or domains alongside CouchDB.

  • #1543: The node-local (default port 5986) /_restart endpoint has been replaced by the clustered (default port 5984) endpoint /_node/$node/_restart and /_node/_local/_restart endpoints. The node-local endpoint has been removed.

  • #1764: All python scripts shipped with CouchDB, including couchup and the dev/run development cluster script, now specify and require Python 3.x.

  • #1396: CouchDB is now compatible with Erlang 21.x.

  • #1680: The embedded version of rebar used to build CouchDB has been updated to the last version of rebar2 available. This assists in building on non-x86 platforms.

16.1.2. Version 2.3.0

16.1.2.1. Features

  • (Multiple) Clustered purge is now available. This feature restores the CouchDB 1.x ability to completely remove any record of a document from a database. Conditions apply; to use the feature safely, and for full details, read the complete Clustered Purge documentation.

  • #1658: A new config setting is available, allowing an administrator to configure an initial list of nodes that should be contacted when a node boots up. Nodes in the seedlist that are successfully reached will be added to that node’s _nodes database automatically, triggering a distributed Erlang connection and replication of the internal system databases to the new node. This can be used instead of manual config or the cluster setup wizard to bootstrap a cluster. The progress of the initial seeding of new nodes is exposed at the GET /_up endpoint.

  • Replication supports ipv6-only peers after updating ibrowse dependency.

  • #1708: The UUID of the server/cluster is once again exposed in the GET / response. This was a regression from CouchDB 1.x.

  • #1722: Stats counts between job runs of the replicator are no longer reset on job restart.

  • #1195, #1742: CouchDB’s _bulk_get implementation now supports the multipart/mixed and multipart/related content types if requested, extending compatibility with third-party replication clients.

16.1.2.2. Performance

  • #1409: CouchDB no longer forces the TCP receive buffer to a fixed size of 256KB, allowing the operating system to dynamically adjust the buffer size. This can lead to siginificantly improved network performance when transferring large attachments.

  • #1423: Mango selector matching now occurs at the shard level, reducing the network traffic within a cluster for a mango query.

  • #1423: Long running operations at the node level could exceed the inter-node timeout, leading to a fabric timeout error in the logfile and a cancellation of the task. Nodes can now ping to stop that from happening.

  • #1560: An optimization to how external data sizes of attachments were recorded was made.

  • #1586: When cleaning up outdated secondary index files, the search is limited to the index directory of a specific database.

  • #1593: The couch_server ETS table now has the read_concurrency option set, improving access to the global list of open database handles.

  • #1593: Messages to update the least-recently used (LRU) cache are not sent when the [couchdb] update_lru_on_read setting is disabled.

  • #1625: All nodes in a cluster now run their own rexi server.

16.1.2.3. Bugfixes

  • #1484: _stats now correctly handles the case where a map function emits an array of integers. This bug was introduced in 2.2.0.

  • #1544: Certain list functions could return a render_error error intermittently.

  • #1550: Replicator _session support was incompatible with CouchDB installations using the require_valid_user = true setting.

  • #1571: Under very heavy load, it was possible that rexi_server could die in such a way that it’s never restarted, leaving a cluster without the ability to issue RPC calls - effectively rendering the cluster useless.

  • #1574: The built-in _sum reduce function has been improved to check if the objects being summed are not overflowing the view storage. Previously, there was no protection for _sum-introduced overflows.

  • #1582: Database creation parameters now have improved validation, giving a more readable error on invalid input.

  • #1588: A missing security check has been restored for the noop /db/_ensure_full_commit call to restore database validation checks.

  • #1591: CouchDB now creates missing shard files when accessing a database if necessary. This handles the situation when, on database creation, no nodes were capable of creating any of the shard files required for that database.

  • #1568: CouchDB now logs a warning if a changes feed is rewound to 0. This can help diagnose problems in busy or malfunctioning clusters.

  • #1596: It is no longer possible that a busy couch_server, under a specific ordering and timing of events, will incorrectly track open_async messages in its mailbox.

  • #1601, #1654: CouchDB now logs better when an error causes it to read past the EOF of a database shard. The check for whether CouchDB is trying to read too many bytes has been correctly separated out from the error indicating it has attempted to read past the EOF.

  • #1613: Local nodes are now filtered out during read repair operations.

  • #1636: A memory leak when replicating over HTTPS and a problem occurs has been squashed.

  • #1635: /_replicate jobs are no longer restarted if parameters haven’t changed.

  • #1612: JavaScript rewrite functions now send the body of the request to the rewritten endpoint.

  • #1631: The replicator no longer crashes if the user has placed an invalid VDU function into one of the _replicator databases.

  • #1644, #1647: It is no longer possible to create illegally-named databases within the reserved system space (_ prefix.)

  • #1650: _bulk_get is once again operational for system databases such as _users.

  • #1652: Access to /_active_tasks is once again restricted to server admins only.

  • #1662: The couch_log application no longer crashes when new, additional information is supplied by a crashing application, or when any of its own children are restarted.

  • #1666: Mango could return an error that would crash the couch_query_servers application. This is no longer the case.

  • #1655: Configuration of ets_lru in chttpd now performs proper error checking of the specified config value.

  • #1667: The snappy dependency has been updated to fix a memory allocation error.

  • #1683: Attempting to create a local document with an invalid revision no longer throws a badarg exception. Also, when setting new_edits to false and performing a bulk write operation, local documents are no longer written into the wrong btree. Finally, it is no longer possible to create a document with an empty ID during a bulk operation with new_edits set to false.

  • #1721: The couchup convenience script for upgrading from CouchDB 1.x now also copies a database’s _security object on migration.

  • #1672: When checking the status of a view compaction immediately after starting it, the total_changes and changes_done fields are now immediately populated with valid values.

  • #1717: If the .ini config file is read only, an attempt to update the config through the HTTP API will now result in a proper eacces error response.

  • #1603: CouchDB now returns the correct total_rows result when querying /{db}/_design_docs.

  • #1629: Internal load validation functions no longer incorrectly hold open a deleted database or its host process.

  • #1746: Server admins defined in the ini file accessing via HTTP API no longer result in the auth cache logging the access as a miss in the statistics.

  • #1607: The replicator no longer fails to re-authenticate to open a remote database when its session cookie times out due to a VDU function forbidding writes or a non-standard cookie expiration duration.

  • #1579: The compaction daemon no longer incorrectly only compacts a single view shard for databases with a q value greater than 1.

  • #1737: CouchDB 2.x now performs as well as 1.x when using a _doc_ids or _design_docs filter on a changes feed.

16.1.2.4. Mango

16.1.2.5. Other

The 2.3.0 release also includes the following minor improvements:

  • Improved test cases:

    • The Elixir test suite has been merged. These test cases are intended to replace the aging, unmaintainable JavaScript test suite, and help reduce our dependency on Mozilla Spidermonkey 1.8.5. The test suite does not yet cover all of the tests that the JS test suite does. Once it achieves full coverage, the JS test suite will be removed.
    • Many racy test cases improved for reliable CI runs.
    • The Makefile targets for list-eunit-* now work correctly on macOS.
    • #1732, #1733, #1736: All of the test suites run and pass on the Windows platform once again.
  • #1597: Off-heap messages, a new feature in Erlang 19+, can now be disabled per module if desired.

  • #1682: A new [feature_flags] config section exists for the purpose of enabling or disabling experimental features by CouchDB developers.

  • A narwhal! OK, no, not really. If you got this far…thank you for reading.