docs/release_notes.adoc - kudu - Git at Google

 // Licensed to the Apache Software Foundation (ASF) under one
 // or more contributor license agreements.  See the NOTICE file
 // distributed with this work for additional information
 // regarding copyright ownership.  The ASF licenses this file
 // to you under the Apache License, Version 2.0 (the
 // "License"); you may not use this file except in compliance
 // with the License.  You may obtain a copy of the License at
 //
 //   http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing,
 // software distributed under the License is distributed on an
 // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 // KIND, either express or implied.  See the License for the
 // specific language governing permissions and limitations
 // under the License.

 [[release_notes]]
 = Apache Kudu 1.12.0 Release Notes

 :author: Kudu Team
 :imagesdir: ./images
 :icons: font
 :toc: left
 :toclevels: 3
 :doctype: book
 :backend: html5
 :sectlinks:
 :experimental:

 [[rn_1.12.0_upgrade_notes]]
 == Upgrade Notes


 [[rn_1.12.0_obsoletions]]
 == Obsoletions

 * The Flume sink has been migrated to the Apache Flume project and removed
   from Kudu. Users depending on the Flume integration can use the old
   `kudu-flume` jars or migrate to the Flume jars containing the Kudu sink.

 * Support for Apache Sentry authorization has been deprecated and may be
   removed in the next minor release. Users depending on the Sentry integration
   should migrate to the Apache Ranger integration for fine-grained authorization.

 * Support for Python 2 has been deprecated and may be removed in the next minor
   release.

 * Support for CentOS/RHEL 6, Debian 8, Ubuntu 14 has been deprecated and may
   be removed in the next minor release.

 [[rn_1.12.0_deprecations]]
 == Deprecations


 [[rn_1.12.0_new_features]]
 == New features

 * Kudu now supports native fine-grained authorization via integration with
   Apache Ranger. Kudu may now enforce access control policies defined for
   Kudu tables and columns stored in Ranger. See the
   link:security.html#fine_grained_authz[authorization documentation]
   for more details.

 * Kudu’s web UI now supports proxying via Apache Knox. Kudu may be deployed
   in a firewalled state behind a Knox Gateway which will forward HTTP requests
   and responses between clients and the Kudu web UI.

 * Kudu’s web UI now supports HTTP keep-alive. Operations that access multiple
   URLs will now reuse a single HTTP connection, improving their performance.

 * The `kudu tserver quiesce` tool is added to quiesce tablet servers. While a
   tablet server is quiescing, it will stop hosting tablet leaders and stop
   serving new scan requests. This can be used to orchestrate a rolling restart
   without stopping on-going Kudu workloads.

 * Introduced `auto` time source for HybridClock timestamps. With
   `--time_source=auto` in AWS and GCE cloud environments, Kudu masters and
   tablet servers use the built-in NTP client synchronized with dedicated NTP
   servers available via host-only networks. With `--time_source=auto` in
   environments other than AWS/GCE, Kudu masters and tablet servers rely on
   their local machine's clock synchronized by NTP. The default setting for
   the HybridClock time source (`--time_source=system`) is backward-compatible,
   requiring the local machine's clock to be synchronized by the kernel's NTP
   discipline.

 * The `kudu cluster rebalance` tool now supports moving replicas away from
   specific tablet servers by supplying the `--ignored_tservers` and
   `--move_replicas_from_ignored_tservers` arguments (see
   link:https://issues.apache.org/jira/browse/KUDU-2914[KUDU-2914] for more
   details).

 * The `kudu table create` tool is added to allow users to specify table
   creation options using JSON.

 * Kudu now supports DATE and VARCHAR data types. See the
   link:http://kudu.apache.org/docs/schema_design.html[schema design documentation]
   for more details.


 [[rn_1.12.0_improvements]]
 == Optimizations and improvements

 * Write Ahead Log file segments and index chunks are now managed by Kudu’s file
   cache. With that, all long-lived file descriptors used by Kudu are managed by
   the file cache, and there’s no longer a need for capacity planning of file
   descriptor usage.

 * Kudu no longer requires the running of `kudu fs update_dirs` to change a
   directory configuration or recover from a disk failure
   (see link:https://issues.apache.org/jira/browse/KUDU-2993[KUDU-2993]).

 * Kudu tablet servers and masters now expose a tablet-level metric
   `num_raft_leaders` for the number of Raft leaders hosted on the server.

 * Kudu's maintenance operation scheduling has been updated to prioritize
   reducing WAL retention under memory pressure. Kudu would previously prioritize
   operations that yielded high-memory reduction, which could result in high WAL
   disk usage in workloads that contained updates
   (see link:https://issues.apache.org/jira/browse/KUDU-3002[KUDU-3002]).

 * A new maintenance operation is introduced to remove rowsets that have had all
   of their rows deleted and whose newest delete operations are considered
   ancient (see link:https://issues.apache.org/jira/browse/KUDU-1625[KUDU-1625]).

 * The built-in NTP client is now fully supported as the time source for Kudu's
   HybridTime clock, i.e. it's no longer marked as experimental. To switch the
   time source from the existing `system` time source (which is the default)
   to the built-in NTP client, use `--time_source=builtin`.

 * Introduced additional metrics for the built-in NTP client
   (see link:https://issues.apache.org/jira/browse/KUDU-3048[KUDU-3048]).

 * Updated `/config` page of masters' and tablet servers' web UI to display
   configured and effective time source. In addition, the effective list of
   reference servers for the built-in NTP client is shown there as well,
   if applicable.

 * `chronyd` (version 3.4 and newer) is now supported as NTP server for
   synchronizing the local machine's clock in a Kudu cluster. It's important to
   have the `rtcsync` option enabled in the configuration of the `chronyd` NTP
   daemon (see link:https://issues.apache.org/jira/browse/KUDU-2573[KUDU-2573]).

 * Kudu now supports building and running on RHEL/CentOS 8. This has been tested
   with CentOS 8.1.

 * The processing of Raft consensus vote requests has been improved to be more
   robust during high contention scenarios like election storms.

 * Added a validator to enforce consistency between the maximum size of an RPC
   and the maximum size of tablet transaction memory, controlled by
   `--rpc_max_message_size` and `--tablet_transaction_memory` flags
   correspondingly.  In prior releases, if the limit on the size of RPC requests
   is increased and the limit on tablet transaction memory size is kept with the
   default setting, certain Raft transactions could be committed but not applied
   (see link:https://issues.apache.org/jira/browse/KUDU-3023[KUDU-3023]).

 * The metrics endpoint now supports filtering metrics by a metric severity level.
   See the link:https://kudu.apache.org/docs/administration.html#_collecting_metrics_via_http[documentation]
   for more details.

 * Many `kudu local_replica` tools are updated to not open the block manager,
   which significantly reduces the amount of IO done when running them (see
   link:https://issues.apache.org/jira/browse/KUDU-3070[KUDU-3070] for more
   details).

 * The Kudu Java client now exposes a way to get the resource metrics associated
   with a given scanner (see
   link:https://issues.apache.org/jira/browse/KUDU-2162[KUDU-2162] for more
   details).

 * Scan predicates are pushed down to RLE decoders, improving
   predicate-evaluation-efficiency in some workloads (see
   link:https://issues.apache.org/jira/browse/KUDU-2852[KUDU-2852] for more
   details).

 * The log block manager will now attempt to use multiple threads to open blocks
   in each data directory, in some tests reducing startup time by up to 20% (see
   link:https://issues.apache.org/jira/browse/KUDU-2977[KUDU-2977] and
   link:https://issues.apache.org/jira/browse/KUDU-3001[KUDU-3001] for more
   details).

 * Kudu's tablet server web UI scans page is updated to show the number of round
   trips per scanner.

 * Kudu's master and tablet server web UIs are updated to show critical
   partition information, including tablet count and on-disk size.

 * Kudu servers now expose the `last_read_elapsed_seconds` and
   `last_write_elapsed_seconds` tablet-level metrics that indicate how long ago
   the most recent read and write operations to a given tablet were.

 * Kudu servers now expose the `transaction_memory_limit_rejections`
   tablet-level metric that tracks the number of transactions rejected because a
   given tablet's transactional memory limit was reached (see
   link:https://issues.apache.org/jira/browse/KUDU-3021[KUDU-3021] for more
   details).

 [[rn_1.12.0_fixed_issues]]
 == Fixed Issues

 * Fixed a bug in which Kudu would not schedule compactions if a server were
   under memory pressure
   (see link:https://issues.apache.org/jira/browse/KUDU-2929[KUDU-2929]).

 * Fixed a bug where DDL operations like ALTER TABLE on tables with huge
   number of partitions might result in a DoS situation for Kudu masters
   (see link:https://issues.apache.org/jira/browse/KUDU-3036[KUDU-3036]).

 * Fixed a bug where Kudu Java client cannot negotiate a secure connection
   with Kudu masters and tablet servers if using BouncyCastle JCE provider
   (see link:https://issues.apache.org/jira/browse/KUDU-3106[KUDU-3106]).

 * Kudu masters will now crash immediately upon hitting a disk failure (see
   link:https://issues.apache.org/jira/browse/KUDU-2904[KUDU-2904] for more details).

 * Fixed an issue in the Kudu master in which delays in receiving tablet server
   heartbeats could result in an excess amount of RPC traffic between the
   masters and tablet servers (see
   link:https://issues.apache.org/jira/browse/KUDU-2992[KUDU-2992] for more
   details).

 * Fixed an issue with Kudu's location placement policy that would place all
   replicas in one location when two locations were available (see
   link:https://issues.apache.org/jira/browse/KUDU-3008[KUDU-3008] for more
   details).

 * The Java client will now correctly propagate timestamps when sending write
   batches (see link:https://issues.apache.org/jira/browse/KUDU-3035[KUDU-3035]
   for more detail).

 * Fixed an issue with the Kudu backup Spark jobs in which Kudu would return
   with a non-zero exit if the job succeeded but backed up no rows (see
   link:https://issues.apache.org/jira/browse/KUDU-3099[KUDU-3099] for more
   details).

 * The `raft_term` and `time_since_last_leader_heartbeat` aggregated table
   metrics will now return the maximum metric reported instead of the sum.

 [[rn_1.12.0_wire_compatibility]]
 == Wire Protocol compatibility

 Kudu 1.12.0 is wire-compatible with previous versions of Kudu:

 * Kudu 1.12 clients may connect to servers running Kudu 1.0 or later. If the client uses
   features that are not available on the target server, an error will be returned.
 * Rolling upgrade between Kudu 1.11 and Kudu 1.12 servers is believed to be possible
   though has not been sufficiently tested. Users are encouraged to shut down all nodes
   in the cluster, upgrade the software, and then restart the daemons on the new version.
 * Kudu 1.0 clients may connect to servers running Kudu 1.12 with the exception of the
   below-mentioned restrictions regarding secure clusters.

 The authentication features introduced in Kudu 1.3 place the following limitations
 on wire compatibility between Kudu 1.12 and versions earlier than 1.3:

 * If a Kudu 1.12 cluster is configured with authentication or encryption set to "required",
   clients older than Kudu 1.3 will be unable to connect.
 * If a Kudu 1.12 cluster is configured with authentication and encryption set to "optional"
   or "disabled", older clients will still be able to connect.

 [[rn_1.12.0_incompatible_changes]]
 == Incompatible Changes in Kudu 1.12.0


 [[rn_1.12.0_client_compatibility]]
 === Client Library Compatibility

 * The Kudu 1.12 Java client library is API- and ABI-compatible with Kudu 1.11. Applications
   written against Kudu 1.11 will compile and run against the Kudu 1.12 client library and
   vice-versa.

 * The Kudu 1.12 {cpp} client is API- and ABI-forward-compatible with Kudu 1.11.
   Applications written and compiled against the Kudu 1.11 client library will run without
   modification against the Kudu 1.12 client library. Applications written and compiled
   against the Kudu 1.12 client library will run without modification against the Kudu 1.11
   client library.

 * The Kudu 1.12 Python client is API-compatible with Kudu 1.11. Applications
   written against Kudu 1.11 will continue to run against the Kudu 1.12 client
   and vice-versa.

 [[rn_1.12.0_known_issues]]
 == Known Issues and Limitations

 Please refer to the link:known_issues.html[Known Issues and Limitations] section of the
 documentation.

 [[rn_1.12.0_contributors]]
 == Contributors

 Kudu 1.12 includes contributions from 33 people, including 8 first-time
 contributors:

 * Andy Singer
 * Michele Milesi
 * Ning Wang
 * Renhai Zhao
 * Sheng Liu
 * Thomas D'Silva
 * Tianhua Huang
 * Waleed Fateem

 Thank you for your help in making Kudu even better!

 [[resources_and_next_steps]]
 == Resources

 - link:http://kudu.apache.org[Kudu Website]
 - link:http://github.com/apache/kudu[Kudu GitHub Repository]
 - link:index.html[Kudu Documentation]
 - link:prior_release_notes.html[Release notes for older releases]

 == Installation Options

 For full installation details, see link:installation.html[Kudu Installation].

 == Next Steps
 - link:quickstart.html[Kudu Quickstart]
 - link:installation.html[Installing Kudu]
 - link:configuration.html[Configuring Kudu]
	// Licensed to the Apache Software Foundation (ASF) under one
	// or more contributor license agreements. See the NOTICE file
	// distributed with this work for additional information
	// regarding copyright ownership. The ASF licenses this file
	// to you under the Apache License, Version 2.0 (the
	// "License"); you may not use this file except in compliance
	// with the License. You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing,
	// software distributed under the License is distributed on an
	// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	// KIND, either express or implied. See the License for the
	// specific language governing permissions and limitations
	// under the License.

	[[release_notes]]
	= Apache Kudu 1.12.0 Release Notes

	:author: Kudu Team
	:imagesdir: ./images
	:icons: font
	:toc: left
	:toclevels: 3
	:doctype: book
	:backend: html5
	:sectlinks:
	:experimental:

	[[rn_1.12.0_upgrade_notes]]
	== Upgrade Notes


	[[rn_1.12.0_obsoletions]]
	== Obsoletions

	* The Flume sink has been migrated to the Apache Flume project and removed
	from Kudu. Users depending on the Flume integration can use the old
	`kudu-flume` jars or migrate to the Flume jars containing the Kudu sink.

	* Support for Apache Sentry authorization has been deprecated and may be
	removed in the next minor release. Users depending on the Sentry integration
	should migrate to the Apache Ranger integration for fine-grained authorization.

	* Support for Python 2 has been deprecated and may be removed in the next minor
	release.

	* Support for CentOS/RHEL 6, Debian 8, Ubuntu 14 has been deprecated and may
	be removed in the next minor release.

	[[rn_1.12.0_deprecations]]
	== Deprecations


	[[rn_1.12.0_new_features]]
	== New features

	* Kudu now supports native fine-grained authorization via integration with
	Apache Ranger. Kudu may now enforce access control policies defined for
	Kudu tables and columns stored in Ranger. See the
	link:security.html#fine_grained_authz[authorization documentation]
	for more details.

	* Kudu’s web UI now supports proxying via Apache Knox. Kudu may be deployed
	in a firewalled state behind a Knox Gateway which will forward HTTP requests
	and responses between clients and the Kudu web UI.

	* Kudu’s web UI now supports HTTP keep-alive. Operations that access multiple
	URLs will now reuse a single HTTP connection, improving their performance.

	* The `kudu tserver quiesce` tool is added to quiesce tablet servers. While a
	tablet server is quiescing, it will stop hosting tablet leaders and stop
	serving new scan requests. This can be used to orchestrate a rolling restart
	without stopping on-going Kudu workloads.

	* Introduced `auto` time source for HybridClock timestamps. With
	`--time_source=auto` in AWS and GCE cloud environments, Kudu masters and
	tablet servers use the built-in NTP client synchronized with dedicated NTP
	servers available via host-only networks. With `--time_source=auto` in
	environments other than AWS/GCE, Kudu masters and tablet servers rely on
	their local machine's clock synchronized by NTP. The default setting for
	the HybridClock time source (`--time_source=system`) is backward-compatible,
	requiring the local machine's clock to be synchronized by the kernel's NTP
	discipline.

	* The `kudu cluster rebalance` tool now supports moving replicas away from
	specific tablet servers by supplying the `--ignored_tservers` and
	`--move_replicas_from_ignored_tservers` arguments (see
	link:https://issues.apache.org/jira/browse/KUDU-2914[KUDU-2914] for more
	details).

	* The `kudu table create` tool is added to allow users to specify table
	creation options using JSON.

	* Kudu now supports DATE and VARCHAR data types. See the
	link:http://kudu.apache.org/docs/schema_design.html[schema design documentation]
	for more details.


	[[rn_1.12.0_improvements]]
	== Optimizations and improvements

	* Write Ahead Log file segments and index chunks are now managed by Kudu’s file
	cache. With that, all long-lived file descriptors used by Kudu are managed by
	the file cache, and there’s no longer a need for capacity planning of file
	descriptor usage.

	* Kudu no longer requires the running of `kudu fs update_dirs` to change a
	directory configuration or recover from a disk failure
	(see link:https://issues.apache.org/jira/browse/KUDU-2993[KUDU-2993]).

	* Kudu tablet servers and masters now expose a tablet-level metric
	`num_raft_leaders` for the number of Raft leaders hosted on the server.

	* Kudu's maintenance operation scheduling has been updated to prioritize
	reducing WAL retention under memory pressure. Kudu would previously prioritize
	operations that yielded high-memory reduction, which could result in high WAL
	disk usage in workloads that contained updates
	(see link:https://issues.apache.org/jira/browse/KUDU-3002[KUDU-3002]).

	* A new maintenance operation is introduced to remove rowsets that have had all
	of their rows deleted and whose newest delete operations are considered
	ancient (see link:https://issues.apache.org/jira/browse/KUDU-1625[KUDU-1625]).

	* The built-in NTP client is now fully supported as the time source for Kudu's
	HybridTime clock, i.e. it's no longer marked as experimental. To switch the
	time source from the existing `system` time source (which is the default)
	to the built-in NTP client, use `--time_source=builtin`.

	* Introduced additional metrics for the built-in NTP client
	(see link:https://issues.apache.org/jira/browse/KUDU-3048[KUDU-3048]).

	* Updated `/config` page of masters' and tablet servers' web UI to display
	configured and effective time source. In addition, the effective list of
	reference servers for the built-in NTP client is shown there as well,
	if applicable.

	* `chronyd` (version 3.4 and newer) is now supported as NTP server for
	synchronizing the local machine's clock in a Kudu cluster. It's important to
	have the `rtcsync` option enabled in the configuration of the `chronyd` NTP
	daemon (see link:https://issues.apache.org/jira/browse/KUDU-2573[KUDU-2573]).

	* Kudu now supports building and running on RHEL/CentOS 8. This has been tested
	with CentOS 8.1.

	* The processing of Raft consensus vote requests has been improved to be more
	robust during high contention scenarios like election storms.

	* Added a validator to enforce consistency between the maximum size of an RPC
	and the maximum size of tablet transaction memory, controlled by
	`--rpc_max_message_size` and `--tablet_transaction_memory` flags
	correspondingly. In prior releases, if the limit on the size of RPC requests
	is increased and the limit on tablet transaction memory size is kept with the
	default setting, certain Raft transactions could be committed but not applied
	(see link:https://issues.apache.org/jira/browse/KUDU-3023[KUDU-3023]).

	* The metrics endpoint now supports filtering metrics by a metric severity level.
	See the link:https://kudu.apache.org/docs/administration.html#_collecting_metrics_via_http[documentation]
	for more details.

	* Many `kudu local_replica` tools are updated to not open the block manager,
	which significantly reduces the amount of IO done when running them (see
	link:https://issues.apache.org/jira/browse/KUDU-3070[KUDU-3070] for more
	details).

	* The Kudu Java client now exposes a way to get the resource metrics associated
	with a given scanner (see
	link:https://issues.apache.org/jira/browse/KUDU-2162[KUDU-2162] for more
	details).

	* Scan predicates are pushed down to RLE decoders, improving
	predicate-evaluation-efficiency in some workloads (see
	link:https://issues.apache.org/jira/browse/KUDU-2852[KUDU-2852] for more
	details).

	* The log block manager will now attempt to use multiple threads to open blocks
	in each data directory, in some tests reducing startup time by up to 20% (see
	link:https://issues.apache.org/jira/browse/KUDU-2977[KUDU-2977] and
	link:https://issues.apache.org/jira/browse/KUDU-3001[KUDU-3001] for more
	details).

	* Kudu's tablet server web UI scans page is updated to show the number of round
	trips per scanner.

	* Kudu's master and tablet server web UIs are updated to show critical
	partition information, including tablet count and on-disk size.

	* Kudu servers now expose the `last_read_elapsed_seconds` and
	`last_write_elapsed_seconds` tablet-level metrics that indicate how long ago
	the most recent read and write operations to a given tablet were.

	* Kudu servers now expose the `transaction_memory_limit_rejections`
	tablet-level metric that tracks the number of transactions rejected because a
	given tablet's transactional memory limit was reached (see
	link:https://issues.apache.org/jira/browse/KUDU-3021[KUDU-3021] for more
	details).

	[[rn_1.12.0_fixed_issues]]
	== Fixed Issues

	* Fixed a bug in which Kudu would not schedule compactions if a server were
	under memory pressure
	(see link:https://issues.apache.org/jira/browse/KUDU-2929[KUDU-2929]).

	* Fixed a bug where DDL operations like ALTER TABLE on tables with huge
	number of partitions might result in a DoS situation for Kudu masters
	(see link:https://issues.apache.org/jira/browse/KUDU-3036[KUDU-3036]).

	* Fixed a bug where Kudu Java client cannot negotiate a secure connection
	with Kudu masters and tablet servers if using BouncyCastle JCE provider
	(see link:https://issues.apache.org/jira/browse/KUDU-3106[KUDU-3106]).

	* Kudu masters will now crash immediately upon hitting a disk failure (see
	link:https://issues.apache.org/jira/browse/KUDU-2904[KUDU-2904] for more details).

	* Fixed an issue in the Kudu master in which delays in receiving tablet server
	heartbeats could result in an excess amount of RPC traffic between the
	masters and tablet servers (see
	link:https://issues.apache.org/jira/browse/KUDU-2992[KUDU-2992] for more
	details).

	* Fixed an issue with Kudu's location placement policy that would place all
	replicas in one location when two locations were available (see
	link:https://issues.apache.org/jira/browse/KUDU-3008[KUDU-3008] for more
	details).

	* The Java client will now correctly propagate timestamps when sending write
	batches (see link:https://issues.apache.org/jira/browse/KUDU-3035[KUDU-3035]
	for more detail).

	* Fixed an issue with the Kudu backup Spark jobs in which Kudu would return
	with a non-zero exit if the job succeeded but backed up no rows (see
	link:https://issues.apache.org/jira/browse/KUDU-3099[KUDU-3099] for more
	details).

	* The `raft_term` and `time_since_last_leader_heartbeat` aggregated table
	metrics will now return the maximum metric reported instead of the sum.

	[[rn_1.12.0_wire_compatibility]]
	== Wire Protocol compatibility

	Kudu 1.12.0 is wire-compatible with previous versions of Kudu:

	* Kudu 1.12 clients may connect to servers running Kudu 1.0 or later. If the client uses
	features that are not available on the target server, an error will be returned.
	* Rolling upgrade between Kudu 1.11 and Kudu 1.12 servers is believed to be possible
	though has not been sufficiently tested. Users are encouraged to shut down all nodes
	in the cluster, upgrade the software, and then restart the daemons on the new version.
	* Kudu 1.0 clients may connect to servers running Kudu 1.12 with the exception of the
	below-mentioned restrictions regarding secure clusters.

	The authentication features introduced in Kudu 1.3 place the following limitations
	on wire compatibility between Kudu 1.12 and versions earlier than 1.3:

	* If a Kudu 1.12 cluster is configured with authentication or encryption set to "required",
	clients older than Kudu 1.3 will be unable to connect.
	* If a Kudu 1.12 cluster is configured with authentication and encryption set to "optional"
	or "disabled", older clients will still be able to connect.

	[[rn_1.12.0_incompatible_changes]]
	== Incompatible Changes in Kudu 1.12.0


	[[rn_1.12.0_client_compatibility]]
	=== Client Library Compatibility

	* The Kudu 1.12 Java client library is API- and ABI-compatible with Kudu 1.11. Applications
	written against Kudu 1.11 will compile and run against the Kudu 1.12 client library and
	vice-versa.

	* The Kudu 1.12 {cpp} client is API- and ABI-forward-compatible with Kudu 1.11.
	Applications written and compiled against the Kudu 1.11 client library will run without
	modification against the Kudu 1.12 client library. Applications written and compiled
	against the Kudu 1.12 client library will run without modification against the Kudu 1.11
	client library.

	* The Kudu 1.12 Python client is API-compatible with Kudu 1.11. Applications
	written against Kudu 1.11 will continue to run against the Kudu 1.12 client
	and vice-versa.

	[[rn_1.12.0_known_issues]]
	== Known Issues and Limitations

	Please refer to the link:known_issues.html[Known Issues and Limitations] section of the
	documentation.

	[[rn_1.12.0_contributors]]
	== Contributors

	Kudu 1.12 includes contributions from 33 people, including 8 first-time
	contributors:

	* Andy Singer
	* Michele Milesi
	* Ning Wang
	* Renhai Zhao
	* Sheng Liu
	* Thomas D'Silva
	* Tianhua Huang
	* Waleed Fateem

	Thank you for your help in making Kudu even better!

	[[resources_and_next_steps]]
	== Resources

	- link:http://kudu.apache.org[Kudu Website]
	- link:http://github.com/apache/kudu[Kudu GitHub Repository]
	- link:index.html[Kudu Documentation]
	- link:prior_release_notes.html[Release notes for older releases]

	== Installation Options

	For full installation details, see link:installation.html[Kudu Installation].

	== Next Steps
	- link:quickstart.html[Kudu Quickstart]
	- link:installation.html[Installing Kudu]
	- link:configuration.html[Configuring Kudu]