Building and Developing HBase

This chapter will be of interest only to those building and developing HBase (i.e., as opposed to + Building and Developing Apache HBase (TM) + This chapter will be of interest only to those building and developing Apache HBase (TM) (i.e., as opposed to just downloading the latest distribution).

- HBase Repositories + Apache HBase Repositories + There are two different repositories for Apache HBase: Subversion (SVN) and Git. The former is the system of record for committers, but the latter is easier to work with to build and contribute. SVN updates get automatically propagated to the Git repo.

SVN -svn co http://svn.apache.org/repos/asf/hbase/trunk hbase-core-trunk +svn co http://svn.apache.org/repos/asf/hbase/trunk hbase-core-trunk -

Git git clone git://git.apache.org/hbase.git -

- - -

+ + +

IDEs

Eclipse

Code Formatting - See HBASE-3678 Add Eclipse-based Apache Formatter to HBase Wiki - for an Eclipse formatter to help ensure your code conforms to HBase'y coding convention. - The issue includes instructions for loading the attached formatter. + Under the dev-support folder, you will find hbase_eclipse_formatter.xml. + We encourage you to have this formatter in place in eclipse when editing HBase code. To load it into eclipse: + +Go to Eclipse->Preferences... +In Preferences, Go to Java->Code Style->Formatter +Import... hbase_eclipse_formatter.xml +Click Apply +Still in Preferences, Go to Java->Editor->Save Actions +Check the following: + +Perform the selected actions on save +Format source code +Format edited lines + + +Click Apply + + + In addition to the automatic formatting, make sure you follow the style guidelines explained in Also, no @author tags - that's a rule. Quality Javadoc comments are appreciated. And include the Apache license. -

Subversive Plugin Download and install the Subversive plugin. Set up an SVN Repository target from , then check out the code. -

+ Git Plugin + If you cloned the project via git, download and install the Git plugin (EGit). Attach to your local git repo (via the Git Repositories window) and you'll be able to see file revision history, generate patches, etc. +

- HBase Project Setup - To set up your Eclipse environment for HBase, close Eclipse and execute... - -mvn eclipse:eclipse - - ... from your local HBase project directory in your workspace to generate some new .project - and .classpathfiles. Then reopen Eclipse. -

- Maven Plugin - Download and install the Maven plugin. For example, Help -> Install New Software -> (search for Maven Plugin) -

+ HBase Project Setup in Eclipse + The easiest way is to use the m2eclipse plugin for Eclipse. Eclipse Indigo or newer has m2eclipse built-in, or it can be found here:http://www.eclipse.org/m2e/. M2Eclipse provides Maven integration for Eclipse - it even lets you use the direct Maven commands from within Eclipse to compile and test your project. + To import the project, you merely need to go to File->Import...Maven->Existing Maven Projects and then point Eclipse at the HBase root directory; m2eclipse will automatically find all the hbase modules for you. + If you install m2eclipse and import HBase in your workspace, you will have to fix your eclipse Build Path. + Remove target folder, add target/generated-jamon + and target/generated-sources/java folders. You may also remove from your Build Path + the exclusions on the src/main/resources and src/test/resources + to avoid error message in the console 'Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.6:run (default) on project hbase: + 'An Ant BuildException has occured: Replace: source file .../target/classes/hbase-default.xml doesn't exist'. This will also + reduce the eclipse build cycles and make your life easier when developing. + +

+ Import into eclipse with the command line + For those not inclined to use m2eclipse, you can generate the Eclipse files from the command line. First, run (you should only have to do this once): + mvn clean install -DskipTests + and then close Eclipse and execute... + mvn eclipse:eclipse + ... from your local HBase project directory in your workspace to generate some new .project + and .classpathfiles. Then reopen Eclipse, or refresh your eclipse project (F5), and import + the .project file in the HBase directory to a workspace. + +

Maven Classpath Variable - The M2_REPO classpath variable needs to be set up for the project. This needs to be set to + The M2_REPO classpath variable needs to be set up for the project. This needs to be set to your local Maven repository, which is usually ~/.m2/repository If this classpath variable is not configured, you will see compile errors in Eclipse like this... Description Resource Path Location Type -The project cannot be built until build path errors are resolved hbase Unknown Java Problem +The project cannot be built until build path errors are resolved hbase Unknown Java Problem Unbound classpath variable: 'M2_REPO/asm/asm/3.1/asm-3.1.jar' in project 'hbase' hbase Build path Build Path Problem -Unbound classpath variable: 'M2_REPO/com/github/stephenc/high-scale-lib/high-scale-lib/1.1.1/high-scale-lib-1.1.1.jar' in project 'hbase' hbase Build path Build Path Problem +Unbound classpath variable: 'M2_REPO/com/github/stephenc/high-scale-lib/high-scale-lib/1.1.1/high-scale-lib-1.1.1.jar' in project 'hbase' hbase Build path Build Path Problem Unbound classpath variable: 'M2_REPO/com/google/guava/guava/r09/guava-r09.jar' in project 'hbase' hbase Build path Build Path Problem Unbound classpath variable: 'M2_REPO/com/google/protobuf/protobuf-java/2.3.0/protobuf-java-2.3.0.jar' in project 'hbase' hbase Build path Build Path Problem Unbound classpath variable: - +

- Import via m2eclipse - If you install the m2eclipse and import the HBase pom.xml in your workspace, you will have to fix your eclipse Build Path. - Remove target folder, add target/generated-jamon - and target/generated-sources/java folders. You may also remove from your Build Path - the exclusions on the src/main/resources and src/test/resources - to avoid error message in the console 'Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.6:run (default) on project hbase: - 'An Ant BuildException has occured: Replace: source file .../target/classes/hbase-default.xml doesn't exist'. This will also - reduce the eclipse build cycles and make your life easier when developing. -

Eclipse Known Issues Eclipse will currently complain about Bytes.java. It is not possible to turn these errors off. - + Description Resource Path Location Type Access restriction: The method arrayBaseOffset(Class) from the type Unsafe is not accessible due to restriction on required library /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/classes.jar Bytes.java /hbase/src/main/java/org/apache/hadoop/hbase/util line 1061 Java Problem Access restriction: The method arrayIndexScale(Class) from the type Unsafe is not accessible due to restriction on required library /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/classes.jar Bytes.java /hbase/src/main/java/org/apache/hadoop/hbase/util line 1064 Java Problem Access restriction: The method getLong(Object, long) from the type Unsafe is not accessible due to restriction on required library /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/classes.jar Bytes.java /hbase/src/main/java/org/apache/hadoop/hbase/util line 1111 Java Problem - +

Eclipse - More Information - For additional information on setting up Eclipse for HBase development on Windows, see + For additional information on setting up Eclipse for HBase development on Windows, see Michael Morello's blog on the topic.

- - + +

- Building HBase - This section will be of interest only to those building HBase from source. - + Building Apache HBase +

+ Basic Compile + Thanks to maven, building HBase is pretty easy. You can read about the various maven commands in , but the simplest command to compile HBase from its java source code is: + +mvn package -DskipTests + + Or, to clean up before compiling: + +mvn clean package -DskipTests + + With Eclipse set up as explained above in , you can also simply use the build command in Eclipse. To create the full installable HBase package takes a little bit more work, so read on. + +

Building in snappy compression support Pass -Dsnappy to trigger the snappy maven profile for building - snappy native libs into hbase. + snappy native libs into hbase. See also

Building the HBase tarball Do the following to build the HBase tarball. - Passing the -Drelease will generate javadoc and run the RAT plugin to verify licenses on source. - % MAVEN_OPTS="-Xmx2g" mvn clean site install assembly:single -Dmaven.test.skip -Prelease + Passing the -Prelease will generate javadoc and run the RAT plugin to verify licenses on source. + % MAVEN_OPTS="-Xmx2g" mvn clean site install assembly:assembly -DskipTests -Prelease

+ +

Build Gotchas + If you see Unable to find resource 'VM_global_library.vm', ignore it. + Its not an error. It is officially ugly though. + +

- Adding an HBase release to Apache's Maven Repository + Adding an Apache HBase release to Apache's Maven Repository Follow the instructions at - Publishing Maven Artifacts. - The 'trick' to making it all work is answering the questions put to you by the mvn release plugin properly, - making sure it is using the actual branch AND before doing the mvn release:perform step, - VERY IMPORTANT, hand edit the release.properties file that was put under ${HBASE_HOME} - by the previous step, release:perform. You need to edit it to make it point at - right locations in SVN. + Publishing Maven Artifacts after + reading the below miscellaney. + + You must use maven 3.0.x (Check by running mvn -version). + + Let me list out the commands I used first. The sections that follow dig in more + on what is going on. In this example, we are releasing the 0.92.2 jar to the apache + maven repository. + + # First make a copy of the tag we want to release; presumes the release has been tagged already + # We do this because we need to make some commits for the mvn release plugin to work. + 853 svn copy -m "Publishing 0.92.2 to mvn" https://svn.apache.org/repos/asf/hbase/tags/0.92.2 https://svn.apache.org/repos/asf/hbase/tags/0.92.2mvn + 857 svn checkout https://svn.apache.org/repos/asf/hbase/tags/0.92.2mvn + 858 cd 0.92.2mvn/ + # Edit the version making it release version with a '-SNAPSHOT' suffix (See below for more on this) + 860 vi pom.xml + 861 svn commit -m "Add SNAPSHOT to the version" pom.xml + 862 ~/bin/mvn/bin/mvn release:clean + 865 ~/bin/mvn/bin/mvn release:prepare + 866 # Answer questions and then ^C to kill the build after the last question. See below for more on this. + 867 vi release.properties + # Change the references to trunk svn to be 0.92.2mvn; the release plugin presumes trunk + # Then restart the release:prepare -- it won't ask questions + # because the properties file exists. + 868 ~/bin/mvn/bin/mvn release:prepare + # The apache-release profile comes from the apache parent pom and does signing of artifacts published + 869 ~/bin/mvn/bin/mvn release:perform -Papache-release + # When done copying up to apache staging repository, + # browse to repository.apache.org, login and finish + # the release as according to the above + # "Publishing Maven Artifacts. + + + Below is more detail on the commmands listed above. + At the mvn release:perform step, before starting, if you are for example + releasing hbase 0.92.2, you need to make sure the pom.xml version is 0.92.2-SNAPSHOT. This needs + to be checked in. Since we do the maven release after actual release, I've been doing this + checkin into a copy of the release tag rather than into the actual release tag itself (presumes the release has been properly tagged in svn). + So, say we released hbase 0.92.2 and now we want to do the release to the maven repository, in svn, the 0.92.2 + release will be tagged 0.92.2. Making the maven release, copy the 0.92.2 tag to 0.92.2mvn. + Check out this tag and change the version therein and commit. + + Currently, the mvn release wants to go against trunk. I haven't figured how to tell it to do otherwise + so I do the below hack. The hack comprises answering the questions put to you by the mvn release plugin properly, + then immediately control-C'ing the build after the last question asked as the build release step starts to run. + After control-C'ing it, You'll notice a release.properties in your build dir. Review it. + Make sure it is using the proper branch -- it tends to use trunk rather than the 0.92.2mvn or whatever + that you want it to use -- so hand edit the release.properties file that was put under ${HBASE_HOME} + by the release:perform invocation. When done, resstart the + release:perform. + + Here is how I'd answer the questions at release:prepare time: + What is the release version for "HBase"? (org.apache.hbase:hbase) 0.92.2: : +What is SCM release tag or label for "HBase"? (org.apache.hbase:hbase) hbase-0.92.2: : 0.92.2mvn +What is the new development version for "HBase"? (org.apache.hbase:hbase) 0.92.3-SNAPSHOT: : +[INFO] Transforming 'HBase'... + + When you run release:perform, pass -Papache-release + else it will not 'sign' the artifacts it uploads. + + A strange issue I ran into was the one where the upload into the apache + repository was being sprayed across multiple apache machines making it so I could + not release. See INFRA-4482 Why is my upload to mvn spread across multiple repositories?. + + Here is my ~/.m2/settings.xml. + This is read by the release plugin. The apache-release profile will pick up your + gpg key setup from here if you've specified it into the file. The password + can be maven encrypted as suggested in the "Publishing Maven Artifacts" but plain + text password works too (just don't let anyone see your local settings.xml). + <settings xmlns="http://maven.apache.org/SETTINGS/1.0.0" + xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" + xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 + http://maven.apache.org/xsd/settings-1.0.0.xsd"> + <servers> + <!- To publish a snapshot of some part of Maven --> + <server> + <id>apache.snapshots.https</id> + <username>YOUR_APACHE_ID + </username> + <password>YOUR_APACHE_PASSWORD + </password> + </server> +  +  + <server> + <id>apache.releases.https</id> + <username>YOUR_APACHE_ID + </username> + <password>YOUR_APACHE_PASSWORD + </password> + </server> + </servers> + <profiles> + <profile> + <id>apache-release</id> + <properties> + <gpg.keyname>YOUR_KEYNAME</gpg.keyname> +  + <gpg.passphrase>YOUR_KEY_PASSWORD + </gpg.passphrase> + </properties> + </profile> + </profiles> +</settings> + + + If you see run into the below, its because you need to edit version in the pom.xml and add -SNAPSHOT to the version (and commit). [INFO] Scanning for projects... @@ -168,73 +308,163 @@ Access restriction: The method getLong(O [INFO] -----------------------------------------------------------------------

Build Gotchas - If you see Unable to find resource 'VM_global_library.vm', ignore it. - Its not an error. It is officially ugly though. - +

+ Generating the HBase Reference Guide + The manual is marked up using docbook. + We then use the docbkx maven plugin + to transform the markup to html. This plugin is run when you specify the site + goal as in when you run mvn site or you can call the plugin explicitly to + just generate the manual by doing mvn docbkx:generate-html + (TODO: It looks like you have to run mvn site first because docbkx wants to + include a transformed hbase-default.xml. Fix). + When you run mvn site, we do the document generation twice, once to generate the multipage + manual and then again for the single page manual (the single page version is easier to search). +

- +

+ Updating hbase.apache.org +

+ Contributing to hbase.apache.org + The Apache HBase apache web site (including this reference guide) is maintained as part of the main Apache HBase source tree, under /src/docbkx and /src/site. The former is this reference guide; the latter, in most cases, are legacy pages that are in the process of being merged into the docbkx tree. + To contribute to the reference guide, edit these files and submit them as a patch (see ). Your Jira should contain a summary of the changes in each section (see HBASE-6081 for an example). + To generate the site locally while you're working on it, run: + mvn site + Then you can load up the generated HTML files in your browser (file are under /target/site). +

+ Publishing hbase.apache.org + As of INFRA-5680 Migrate apache hbase website, + to publish the website, build it, and then deploy it over a checkout of https://svn.apache.org/repos/asf/hbase/hbase.apache.org/trunk, + and then check it in. For example, if trunk is checked out out at /Users/stack/checkouts/trunk + and hbase.apache.org is checked out at /Users/stack/checkouts/hbase.apache.org/trunk, to update + the site, do the following: + + # Build the site and deploy it to the checked out directory + # Getting the javadoc into site is a little tricky. You have to build it independent, then + # 'aggregate' it at top-level so the pre-site site lifecycle step can find it; that is + # what the javadoc:javadoc and javadoc:aggregate is about. + $ MAVEN_OPTS=" -Xmx3g" mvn clean -DskipTests javadoc:javadoc javadoc:aggregate site site:stage -DstagingDirectory=/Users/stack/checkouts/hbase.apache.org/trunk + # Check the deployed site by viewing in a brower. + # If all is good, commit it and it will show up at http://hbase.apache.org + # + $ cd /Users/stack/checkouts/hbase.apache.org/trunk + $ svn commit -m 'Committing latest version of website...' + + +

Tests -HBase tests are divided into two groups: and -. -Unit tests are run by the Apache Continuous Integration server and by developers -when they are verifying a fix does not cause breakage elsewhere in the code base. -Integration tests are generally long-running tests that are invoked out-of-bound of -the CI server when you want to do more intensive testing beyond the unit test set. -Integration tests, for example, are run proving a release candidate or a production -deploy. Below we go into more detail on each of these test types. Developers at a -minimum should familiarize themselves with the unit test detail; unit tests in -HBase have a character not usually seen in other projects. + Developers, at a minimum, should familiarize themselves with the unit test detail; unit tests in +HBase have a character not usually seen in other projects. + +

+Apache HBase Modules +As of 0.96, Apache HBase is split into multiple modules which creates "interesting" rules for +how and where tests are written. If you are writting code for hbase-server, see + for how to write your tests; these tests can spin +up a minicluster and will need to be categorized. For any other module, for example +hbase-common, the tests must be strict unit tests and just test the class +under test - no use of the HBaseTestingUtility or minicluster is allowed (or even possible +given the dependency tree). +

+ Running Tests in other Modules + If the module you are developing in has no other dependencies on other HBase modules, then + you can cd into that module and just run: + mvn test + which will just run the tests IN THAT MODULE. If there are other dependencies on other modules, + then you will have run the command from the ROOT HBASE DIRECTORY. This will run the tests in the other + modules, unless you specify to skip the tests in that module. For instance, to skip the tests in the hbase-server module, + you would run: + mvn clean test -PskipServerTests + from the top level directory to run all the tests in modules other than hbase-server. Note that you + can specify to skip tests in multiple modules as well as just for a single module. For example, to skip + the tests in hbase-server and hbase-common, you would run: + mvn clean test -PskipServerTests -PskipCommonTests + Also, keep in mind that if you are running tests in the hbase-server module you will need to + apply the maven profiles discussed in to get the tests to run properly. +

Unit Tests -HBase unit tests are subdivided into three categories: small, medium and large, with -corresponding JUnit categories: +Apache HBase unit tests are subdivided into four categories: small, medium, large, and +integration with corresponding JUnit categories: SmallTests, MediumTests, -LargeTests. JUnit categories are denoted using java annotations -and look like this in your unit test code. +LargeTests, IntegrationTests. +JUnit categories are denoted using java annotations and look like this in your unit test code. ... @Category(SmallTests.class) public class TestHRegionInfo { - @Test public void testCreateHRegionInfoName() throws Exception { // ... } } -The above example shows how to mark a test as belonging to the small category. +The above example shows how to mark a unit test as belonging to the small category. +All unit tests in HBase have a categorization. +The first three categories, small, medium, and large are for tests run when +you type $ mvn test; i.e. these three categorizations are for +HBase unit tests. The integration category is for not for unit tests but for integration +tests. These are run when you invoke $ mvn verify. Integration tests +are described in integration tests section and will not be discussed further +in this section on HBase unit tests. + +Apache HBase uses a patched maven surefire plugin and maven profiles to implement +its unit test characterizations. + +Read the below to figure which annotation of the set small, medium, and large to +put on your new HBase unit test. + + +

+Small Tests<indexterm><primary>SmallTests</primary></indexterm> + Small tests are executed in a shared JVM. We put in this category all the tests that can -be executed quickly in a shared JVM. The maximum execution time for a test is 15 seconds, -and they do not use a cluster. Medium tests represent tests that must be executed +be executed quickly in a shared JVM. The maximum execution time for a small test is 15 seconds, +and small tests should not use a (mini)cluster. +

+ +

+Medium Tests<indexterm><primary>MediumTests</primary></indexterm> +Medium tests represent tests that must be executed before proposing a patch. They are designed to run in less than 30 minutes altogether, and are quite stable in their results. They are designed to last less than 50 seconds individually. They can use a cluster, and each of them is executed in a separate JVM. -Large tests are everything else. They are typically integration-like -tests (yes, some large tests should be moved out to be HBase ), -regression tests for specific bugs, timeout tests, performance tests. + +

+ +

+Large Tests<indexterm><primary>LargeTests</primary></indexterm> +Large tests are everything else. They are typically large-scale +tests, regression tests for specific bugs, timeout tests, performance tests. They are executed before a commit on the pre-integration machines. They can be run on the developer machine as well. -HBase uses a patched maven surefire plugin and maven profiles to implement its -unit test characterizations. +

+Integration Tests<indexterm><primary>IntegrationTests</primary></indexterm> +Integration tests are system level tests. See +integration tests section for more info. + +

Running tests -Below we describe how to run the HBase junit categories. +Below we describe how to run the Apache HBase junit categories.

Default: small and medium category tests -Running mvn test will execute all small tests in a single JVM and medium tests in a separate JVM for -each test instance. Medium tests are NOT executed if there is an error in a small test. +Running mvn test will execute all small tests in a single JVM +(no fork) and then medium tests in a separate JVM for each test instance. +Medium tests are NOT executed if there is an error in a small test. Large tests are NOT executed. There is one report for small tests, and one report for -medium tests if they are executed. To run small and medium tests with the security -profile enabled, do mvn test -P security +medium tests if they are executed.

@@ -244,42 +474,69 @@ profile enabled, do mvn will execute small tests in a single JVM then medium and large tests in a separate JVM for each test. Medium and large tests are NOT executed if there is an error in a small test. Large tests are NOT executed if there is an error in a small or medium test. -There is one report for small tests, and one report for medium and large tests if they are executed +There is one report for small tests, and one report for medium and large tests if they are executed.

Running a single test or all tests in a package To run an individual test, e.g. MyTest, do -mvn test -P localTests -Dtest=MyTest You can also +mvn test -Dtest=MyTest You can also pass multiple, individual tests as a comma-delimited list: -mvn test -P localTests -Dtest=MyTest1,MyTest2,MyTest3 +mvn test -Dtest=MyTest1,MyTest2,MyTest3 You can also pass a package, which will run all tests under the package: -mvn test -P localTests -Dtest=org.apache.hadoop.hbase.client.* -To run a single test with the security profile enabled: -mvn test -P security,localTests -Dtest=TestGet +mvn test -Dtest=org.apache.hadoop.hbase.client.* -The -P localTests will remove the JUnit category effect (without this specific profile, -the profiles are taken into account). It will actually use the official release of surefire -and the old connector (The HBase build uses a patched version of the maven surefire plugin). -junit tests are executed in separated JVM. You will see a new message at the end of the -report: "[INFO] Tests are skipped". It's harmless. +When -Dtest is specified, localTests profile will be used. It will use the official release +of maven surefire, rather than our custom surefire plugin, and the old connector (The HBase build uses a patched +version of the maven surefire plugin). Each junit tests is executed in a separate JVM (A fork per test class). +There is no parallelization when tests are running in this mode. You will see a new message at the end of the +-report: "[INFO] Tests are skipped". It's harmless. While you need to make sure the sum of Tests run: in +the Results : section of test reports matching the number of tests you specified because no +error will be reported when a non-existent test case is specified.

Other test invocation permutations -Running mvn test -P runSmallTests will execute small tests only, in a single JVM. +Running mvn test -P runSmallTests will execute "small" tests only, using a single JVM. + +Running mvn test -P runMediumTests will execute "medium" tests only, launching a new JVM for each test-class. -Running mvn test -P runMediumTests will execute medium tests in a single JVM. +Running mvn test -P runLargeTests will execute "large" tests only, launching a new JVM for each test-class. -Running mvn test -P runLargeTests execute medium tests in a single JVM. +For convenience, you can run mvn test -P runDevTests to execute both small and medium tests, using a single JVM. +

+ +

+Running tests faster + +By default, $ mvn test -P runAllTests runs 5 tests in parallel. +It can be increased on a developer's machine. Allowing that you can have 2 +tests in parallel per core, and you need about 2Gb of memory per test (at the +extreme), if you have an 8 core, 24Gb box, you can have 16 tests in parallel. +but the memory available limits it to 12 (24/2), To run all tests with 12 tests +in parallell, do this: +mvn test -P runAllTests -Dsurefire.secondPartThreadCount=12. +To increase the speed, you can as well use a ramdisk. You will need 2Gb of memory +to run all tests. You will also need to delete the files between two test run. +The typical way to configure a ramdisk on Linux is: +$ sudo mkdir /ram2G +sudo mount -t tmpfs -o size=2048M tmpfs /ram2G +You can then use it to run all HBase tests with the command: +mvn test -P runAllTests -Dsurefire.secondPartThreadCount=12 -Dtest.build.data.basedirectory=/ram2G + +

+<command>hbasetests.sh</command> It's also possible to use the script hbasetests.sh. This script runs the medium and -large tests in parallel with two maven instances, and provide a single report. +large tests in parallel with two maven instances, and provides a single report. This script does not use +the hbase version of surefire so no parallelization is being done other than the two maven instances the +script sets up. It must be executed from the directory which contains the pom.xml. For example running ./dev-support/hbasetests.sh will execute small and medium tests. @@ -288,6 +545,26 @@ Running ./dev-support/hb second time, in a separate jvm and without parallelisation.

+Test Resource Checker<indexterm><primary>Test Resource Checker</primary></indexterm> + +A custom Maven SureFire plugin listener checks a number of resources before +and after each HBase unit test runs and logs its findings at the end of the test +output files which can be found in target/surefire-reports +per Maven module (Tests write test reports named for the test class into this directory. +Check the *-out.txt files). The resources counted are the number +of threads, the number of file descriptors, etc. If the number has increased, it adds +a LEAK? comment in the logs. As you can have an HBase instance +running in the background, some threads can be deleted/created without any specific +action in the test. However, if the test does not work as expected, or if the test +should not impact these resources, it's worth checking these log lines +...hbase.ResourceChecker(157): before... and +...hbase.ResourceChecker(157): after.... For example: + +2012-09-26 09:22:15,315 INFO [pool-1-thread-1] hbase.ResourceChecker(157): after: regionserver.TestColumnSeeking#testReseeking Thread=65 (was 65), OpenFileDescriptor=107 (was 107), MaxFileDescriptor=10240 (was 10240), ConnectionCount=1 (was 1) + + +

@@ -307,8 +584,12 @@ Tests should not overlog. More than 100 Tests can be written with HBaseTestingUtility. This class offers helper functions to create a temp directory and do the cleanup, or to start a cluster. -Categories and execution time + +

+Categories and execution time + All tests must be categorized, if not they could be skipped. @@ -345,30 +626,50 @@ As most as possible, tests should use th

Integration Tests -HBase integration Tests are tests that are beyond HBase unit tests. They +HBase integration/system tests are tests that are beyond HBase unit tests. They are generally long-lasting, sizeable (the test can be asked to 1M rows or 1B rows), targetable (they can take configuration that will point them at the ready-made cluster they are to run against; integration tests do not include cluster start/stop code), and verifying success, integration tests rely on public APIs only; they do not -attempt to examine server internals asserring success/fail. Integration tests +attempt to examine server internals asserting success/fail. Integration tests are what you would run when you need to more elaborate proofing of a release candidate beyond what unit tests can do. They are not generally run on the Apache Continuous Integration -build server. +build server, however, some sites opt to run integration tests as a part of their +continuous testing on an actual cluster. -Integration tests currently live under the src/test directory and -will match the regex: **/IntegrationTest*.java. +Integration tests currently live under the src/test directory +in the hbase-it submodule and will match the regex: **/IntegrationTest*.java. +All integration tests are also annotated with @Category(IntegrationTests.class). + + +Integration tests can be run in two modes: using a mini cluster, or against an actual distributed cluster. +Maven failsafe is used to run the tests using the mini cluster. IntegrationTestsDriver class is used for +executing the tests against a distributed cluster. Integration tests SHOULD NOT assume that they are running against a +mini cluster, and SHOULD NOT use private API's to access cluster state. To interact with the distributed or mini +cluster uniformly, IntegrationTestingUtility, and HBaseCluster classes, +and public client API's can be used. + + +

+Running integration tests against mini cluster HBase 0.92 added a verify maven target. Invoking it, for example by doing mvn verify, will run all the phases up to and including the verify phase via the maven failsafe plugin, running all the above mentioned HBase unit tests as well as tests that are in the HBase integration test group. -If you just want to run the integration tests, you need to run two commands. First: +After you have completed + mvn install -DskipTests +You can run just the integration tests by invoking: + +cd hbase-it +mvn verify + +If you just want to run the integration tests in top-level, you need to run two commands. First: mvn failsafe:integration-test This actually runs ALL the integration tests. This command will always output BUILD SUCCESS even if there are test failures. @@ -379,75 +680,170 @@ This actually runs ALL the integration t

Running a subset of Integration tests - This is very similar to how you specify running a subset of unit tests (see above). + This is very similar to how you specify running a subset of unit tests (see above), but use the property + it.test instead of test. To just run IntegrationTestClassXYZ.java, use: - mvn failsafe:integration-test -Dtest=IntegrationTestClassXYZ - Pretty similar, right? + mvn failsafe:integration-test -Dit.test=IntegrationTestClassXYZ The next thing you might want to do is run groups of integration tests, say all integration tests that are named IntegrationTestClassX*.java: - mvn failsafe:integration-test -Dtest=*ClassX* + mvn failsafe:integration-test -Dit.test=*ClassX* This runs everything that is an integration test that matches *ClassX*. This means anything matching: "**/IntegrationTest*ClassX*". You can also run multiple groups of integration tests using comma-delimited lists (similar to unit tests). Using a list of matches still supports full regex matching for each of the groups.This would look something like: - mvn failsafe:integration-test -Dtest=*ClassX*, *ClassY + mvn failsafe:integration-test -Dit.test=*ClassX*, *ClassY

+Running integration tests against distributed cluster + +If you have an already-setup HBase cluster, you can launch the integration tests by invoking the class IntegrationTestsDriver. You may have to +run test-compile first. The configuration will be picked by the bin/hbase script. +mvn test-compile +Then launch the tests with: +bin/hbase [--config config_dir] org.apache.hadoop.hbase.IntegrationTestsDriver [-test=class_regex] + +This execution will launch the tests under hbase-it/src/test, having @Category(IntegrationTests.class) annotation, +and a name starting with IntegrationTests. If specified, class_regex will be used to filter test classes. The regex is checked against full class name; so, part of class name can be used. +IntegrationTestsDriver uses Junit to run the tests. Currently there is no support for running integration tests against a distributed cluster using maven (see HBASE-6201). + + + +The tests interact with the distributed cluster by using the methods in the DistributedHBaseCluster (implementing HBaseCluster) class, which in turn uses a pluggable ClusterManager. Concrete implementations provide actual functionality for carrying out deployment-specific and environment-dependent tasks (SSH, etc). The default ClusterManager is HBaseClusterManager, which uses SSH to remotely execute start/stop/kill/signal commands, and assumes some posix commands (ps, etc). Also assumes the user running the test has enough "power" to start/stop servers on the remote machines. By default, it picks up HBASE_SSH_OPTS, HBASE_HOME, HBASE_CONF_DIR from the env, and uses bin/hbase-daemon.sh to carry out the actions. Currently tarball deployments, deployments which uses hbase-daemons.sh, and Apache Ambari deployments are supported. /etc/init.d/ scripts are not supported for now, but it can be easily added. For other deployment options, a ClusterManager can be implemented and plugged in. + +

+ +

+Destructive integration / system tests + + In 0.96, a tool named ChaosMonkey has been introduced. It is modeled after the same-named tool by Netflix. +Some of the tests use ChaosMonkey to simulate faults in the running cluster in the way of killing random servers, +disconnecting servers, etc. ChaosMonkey can also be used as a stand-alone tool to run a (misbehaving) policy while you +are running other tests. + + + +ChaosMonkey defines Action's and Policy's. Actions are sequences of events. We have at least the following actions: + +Restart active master (sleep 5 sec) +Restart random regionserver (sleep 5 sec) +Restart random regionserver (sleep 60 sec) +Restart META regionserver (sleep 5 sec) +Restart ROOT regionserver (sleep 5 sec) +Batch restart of 50% of regionservers (sleep 5 sec) +Rolling restart of 100% of regionservers (sleep 5 sec) + + +Policies on the other hand are responsible for executing the actions based on a strategy. +The default policy is to execute a random action every minute based on predefined action +weights. ChaosMonkey executes predefined named policies until it is stopped. More than one +policy can be active at any time. + + + + To run ChaosMonkey as a standalone tool deploy your HBase cluster as usual. ChaosMonkey uses the configuration +from the bin/hbase script, thus no extra configuration needs to be done. You can invoke the ChaosMonkey by running: +bin/hbase org.apache.hadoop.hbase.util.ChaosMonkey + +This will output smt like: + +12/11/19 23:21:57 INFO util.ChaosMonkey: Using ChaosMonkey Policy: class org.apache.hadoop.hbase.util.ChaosMonkey$PeriodicRandomActionPolicy, period:60000 +12/11/19 23:21:57 INFO util.ChaosMonkey: Sleeping for 26953 to add jitter +12/11/19 23:22:24 INFO util.ChaosMonkey: Performing action: Restart active master +12/11/19 23:22:24 INFO util.ChaosMonkey: Killing master:master.example.com,60000,1353367210440 +12/11/19 23:22:24 INFO hbase.HBaseCluster: Aborting Master: master.example.com,60000,1353367210440 +12/11/19 23:22:24 INFO hbase.ClusterManager: Executing remote command: ps aux | grep master | grep -v grep | tr -s ' ' | cut -d ' ' -f2 | xargs kill -s SIGKILL , hostname:master.example.com +12/11/19 23:22:25 INFO hbase.ClusterManager: Executed remote command, exit code:0 , output: +12/11/19 23:22:25 INFO hbase.HBaseCluster: Waiting service:master to stop: master.example.com,60000,1353367210440 +12/11/19 23:22:25 INFO hbase.ClusterManager: Executing remote command: ps aux | grep master | grep -v grep | tr -s ' ' | cut -d ' ' -f2 , hostname:master.example.com +12/11/19 23:22:25 INFO hbase.ClusterManager: Executed remote command, exit code:0 , output: +12/11/19 23:22:25 INFO util.ChaosMonkey: Killed master server:master.example.com,60000,1353367210440 +12/11/19 23:22:25 INFO util.ChaosMonkey: Sleeping for:5000 +12/11/19 23:22:30 INFO util.ChaosMonkey: Starting master:master.example.com +12/11/19 23:22:30 INFO hbase.HBaseCluster: Starting Master on: master.example.com +12/11/19 23:22:30 INFO hbase.ClusterManager: Executing remote command: /homes/enis/code/hbase-0.94/bin/../bin/hbase-daemon.sh --config /homes/enis/code/hbase-0.94/bin/../conf start master , hostname:master.example.com +12/11/19 23:22:31 INFO hbase.ClusterManager: Executed remote command, exit code:0 , output:starting master, logging to /homes/enis/code/hbase-0.94/bin/../logs/hbase-enis-master-master.example.com.out +.... +12/11/19 23:22:33 INFO util.ChaosMonkey: Started master: master.example.com,60000,1353367210440 +12/11/19 23:22:33 INFO util.ChaosMonkey: Sleeping for:51321 +12/11/19 23:23:24 INFO util.ChaosMonkey: Performing action: Restart random region server +12/11/19 23:23:24 INFO util.ChaosMonkey: Killing region server:rs3.example.com,60020,1353367027826 +12/11/19 23:23:24 INFO hbase.HBaseCluster: Aborting RS: rs3.example.com,60020,1353367027826 +12/11/19 23:23:24 INFO hbase.ClusterManager: Executing remote command: ps aux | grep regionserver | grep -v grep | tr -s ' ' | cut -d ' ' -f2 | xargs kill -s SIGKILL , hostname:rs3.example.com +12/11/19 23:23:25 INFO hbase.ClusterManager: Executed remote command, exit code:0 , output: +12/11/19 23:23:25 INFO hbase.HBaseCluster: Waiting service:regionserver to stop: rs3.example.com,60020,1353367027826 +12/11/19 23:23:25 INFO hbase.ClusterManager: Executing remote command: ps aux | grep regionserver | grep -v grep | tr -s ' ' | cut -d ' ' -f2 , hostname:rs3.example.com +12/11/19 23:23:25 INFO hbase.ClusterManager: Executed remote command, exit code:0 , output: +12/11/19 23:23:25 INFO util.ChaosMonkey: Killed region server:rs3.example.com,60020,1353367027826. Reported num of rs:6 +12/11/19 23:23:25 INFO util.ChaosMonkey: Sleeping for:60000 +12/11/19 23:24:25 INFO util.ChaosMonkey: Starting region server:rs3.example.com +12/11/19 23:24:25 INFO hbase.HBaseCluster: Starting RS on: rs3.example.com +12/11/19 23:24:25 INFO hbase.ClusterManager: Executing remote command: /homes/enis/code/hbase-0.94/bin/../bin/hbase-daemon.sh --config /homes/enis/code/hbase-0.94/bin/../conf start regionserver , hostname:rs3.example.com +12/11/19 23:24:26 INFO hbase.ClusterManager: Executed remote command, exit code:0 , output:starting regionserver, logging to /homes/enis/code/hbase-0.94/bin/../logs/hbase-enis-regionserver-rs3.example.com.out + +12/11/19 23:24:27 INFO util.ChaosMonkey: Started region server:rs3.example.com,60020,1353367027826. Reported num of rs:6 + + +As you can see from the log, ChaosMonkey started the default PeriodicRandomActionPolicy, which is configured with all the available actions, and ran RestartActiveMaster and RestartRandomRs actions. ChaosMonkey tool, if run from command line, will keep on running until the process is killed. + +

+ - -

+ +

Maven Build Commands All commands executed from the local HBase project directory. Note: use Maven 3 (Maven 2 may work but we suggest you use Maven 3). -

Compile mvn compile -

Running all or individual Unit Tests See the section above in -

- Running all or individual Integration Tests - See - -

- -

- To build against hadoop 0.22.x or 0.23.x - -mvn -Dhadoop.profile=22 ... - -That is, designate build with hadoop.profile 22. Pass 23 for hadoop.profile to build against hadoop 0.23. -Tests do not all pass as of this writing so you may need ot pass -DskipTests unless you are inclined -to fix the failing tests. - +

+ Building against various hadoop versions. + As of 0.96, Apache HBase supports building against Apache Hadoop versions: 1.0.3, 2.0.0-alpha and 3.0.0-SNAPSHOT. + By default, we will build with Hadoop-1.0.3. To change the version to run with Hadoop-2.0.0-alpha, you would run: + mvn -Dhadoop.profile=2.0 ... + + That is, designate build with hadoop.profile 2.0. Pass 2.0 for hadoop.profile to build against hadoop 2.0. + Tests may not all pass as of this writing so you may need to pass -DskipTests unless you are inclined + to fix the failing tests. + + Similarly, for 3.0, you would just replace the profile value. Note that Hadoop-3.0.0-SNAPSHOT does not currently have a deployed maven artificat - you will need to build and install your own in your local maven repository if you want to run against this profile. + + + In earilier verions of Apache HBase, you can build against older versions of Apache Hadoop, notably, Hadoop 0.22.x and 0.23.x. + If you are running, for example HBase-0.94 and wanted to build against Hadoop 0.23.x, you would run with: + mvn -Dhadoop.profile=22 ...

- -

+ +

Getting Involved - HBase gets better only when people contribute! + Apache HBase gets better only when people contribute! - As HBase is an Apache Software Foundation project, see for more information about how the ASF functions. + As Apache HBase is an Apache Software Foundation project, see for more information about how the ASF functions.

Mailing Lists - Sign up for the dev-list and the user-list. See the + Sign up for the dev-list and the user-list. See the mailing lists page. - Posing questions - and helping to answer other people's questions - is encouraged! - There are varying levels of experience on both lists so patience and politeness are encouraged (and please - stay on topic.) + Posing questions - and helping to answer other people's questions - is encouraged! + There are varying levels of experience on both lists so patience and politeness are encouraged (and please + stay on topic.)

Jira - Check for existing issues in Jira. + Check for existing issues in Jira. If it's either a new feature request, enhancement, or a bug, file a ticket.

Jira Priorities @@ -457,10 +853,10 @@ to fix the failing tests. Critical: The issue described can cause data loss or cluster instability in some cases. Major: Important but not tragic issues, like updates to the client API that will add a lot of much-needed functionality or significant bugs that need to be fixed but that don't cause data loss. - Minor: Useful enhancements and annoying but not damaging bugs. - Trivial: Useful enhancements but generally cosmetic. - - + Minor: Useful enhancements and annoying but not damaging bugs. + Trivial: Useful enhancements but generally cosmetic. + +

Code Blocks in Jira Comments @@ -475,15 +871,15 @@ to fix the failing tests.

- +

Developing

Codelines Most development is done on TRUNK. However, there are branches for minor releases (e.g., 0.90.1, 0.90.2, and 0.90.3 are on the 0.90 branch). If you have any questions on this just send an email to the dev dist-list.

- -

+ +

Unit Tests In HBase we use JUnit 4. If you need to run miniclusters of HDFS, ZooKeeper, HBase, or MapReduce testing, @@ -506,30 +902,82 @@ to fix the failing tests.

Code Standards See and . -

+ Also, please pay attention to the interface stability/audience classifications that you + will see all over our code base. They look like this at the head of the class: + @InterfaceAudience.Public +@InterfaceStability.Stable + + If the InterfaceAudience is Private, + we can change the class (and we do not need to include a InterfaceStability mark). + If a class is marked Public but its InterfaceStability + is marked Unstable, we can change it. If it's + marked Public/Evolving, we're allowed to change it + but should try not to. If it's Public and Stable + we can't change it without a deprecation path or with a really GREAT reason. + When you add new classes, mark them with the annotations above if publically accessible. + If you are not cleared on how to mark your additions, ask up on the dev list. + + This convention comes from our parent project Hadoop. +

+ +

+ Invariants + We don't have many but what we have we list below. All are subject to challenge of + course but until then, please hold to the rules of the road. + +

+ No permanent state in ZooKeeper + ZooKeeper state should transient (treat it like memory). If deleted, hbase + should be able to recover and essentially be in the same stateThere are currently + a few exceptions that we need to fix around whether a table is enabled or disabled. + +

+ +

+ Running In-Situ + If you are developing Apache HBase, frequently it is useful to test your changes against a more-real cluster than what you find in unit tests. In this case, HBase can be run directly from the source in local-mode. + All you need to do is run: + + ${HBASE_HOME}/bin/start-hbase.sh + + This will spin up a full local-cluster, just as if you had packaged up HBase and installed it on your machine. + + Keep in mind that you will need to have installed HBase into your local maven repository for the in-situ cluster to work properly. That is, you will need to run: + mvn clean install -DskipTests + to ensure that maven can find the correct classpath and dependencies. Generally, the above command + is just a good thing to try running first, if maven is acting oddly. +

Submitting Patches + If you are new to submitting patches to open source or new to submitting patches to Apache, + I'd suggest you start by reading the On Contributing Patches + page from Apache Commons Project. Its a nice overview that + applies equally to the Apache HBase Project.

Create Patch - Patch files can be easily generated from Eclipse, for example by selecting "Team -> Create Patch". + See the aforementioned Apache Commons link for how to make patches against a checked out subversion + repository. Patch files can also be easily generated from Eclipse, for example by selecting "Team -> Create Patch". Patches can also be created by git diff and svn diff. - Please submit one patch-file per Jira. For example, if multiple files are changed make sure the + Please submit one patch-file per Jira. For example, if multiple files are changed make sure the selected resource when generating the patch is a directory. Patch files can reflect changes in multiple files. Make sure you review for code style.

Patch File Naming - The patch file should have the HBase Jira ticket in the name. For example, if a patch was submitted for Foo.java, then - a patch file called Foo_HBASE_XXXX.patch would be acceptable where XXXX is the HBase Jira number. + The patch file should have the Apache HBase Jira ticket in the name. For example, if a patch was submitted for Foo.java, then + a patch file called Foo_HBASE_XXXX.patch would be acceptable where XXXX is the Apache HBase Jira number. If you generating from a branch, then including the target branch in the filename is advised, e.g., HBASE-XXXX-0.90.patch. @@ -539,26 +987,30 @@ to fix the failing tests. Yes, please. Please try to include unit tests with every code patch (and especially new classes and large changes). Make sure unit tests pass locally before submitting the patch. Also, see . + If you are creating a new unit test class, notice how other unit test classes have classification/sizing + annotations at the top and a static method on the end. Be sure to include these in any new unit test files + you generate. See for more on how the annotations work. +

Attach Patch to Jira The patch should be attached to the associated Jira ticket "More Actions -> Attach Files". Make sure you click the ASF license inclusion, otherwise the patch can't be considered for inclusion. - Once attached to the ticket, click "Submit Patch" and + Once attached to the ticket, click "Submit Patch" and the status of the ticket will change. Committers will review submitted patches for inclusion into the codebase. Please understand that not every patch may get committed, and that feedback will likely be provided on the patch. Fear not, though, - because the HBase community is helpful! + because the Apache HBase community is helpful!

- +

Common Patch Feedback The following items are representative of common patch feedback. Your patch process will go faster if these are taken into account before submission. - See the Java coding standards + See the Java coding standards for more information on coding conventions in Java.

@@ -567,7 +1019,7 @@ to fix the failing tests. if ( foo.equals( bar ) ) { // don't do this - ... do this instead... + ... do this instead... if (foo.equals(bar)) { @@ -576,9 +1028,9 @@ if (foo.equals(bar)) { foo = barArray[ i ]; // don't do this - ... do this instead... + ... do this instead... -foo = barArray[i]; +foo = barArray[i];

@@ -589,7 +1041,7 @@ foo = barArray[i]; public void readFields(DataInput arg0) throws IOException { // don't do this foo = arg0.readUTF(); // don't do this - ... do this instead ... + ... do this instead ... public void readFields(DataInput di) throws IOException { foo = di.readUTF(); @@ -600,19 +1052,14 @@ foo = barArray[i];

Long Lines - Keep lines less than 80 characters. - -Bar bar = foo.veryLongMethodWithManyArguments(argument1, argument2, argument3, argument4, argument5); // don't do this - - ... do this instead ... + Keep lines less than 100 characters. -Bar bar = foo.veryLongMethodWithManyArguments(argument1, - argument2, argument3,argument4, argument5); +Bar bar = foo.veryLongMethodWithManyArguments(argument1, argument2, argument3, argument4, argument5, argument6, argument7, argument8, argument9); // don't do this - ... or this, whichever looks better ... + ... do something like this instead ... Bar bar = foo.veryLongMethodWithManyArguments( - argument1, argument2, argument3,argument4, argument5); + argument1, argument2, argument3,argument4, argument5, argument6, argument7, argument8, argument9);

@@ -624,11 +1071,17 @@ Bar bar = foo.veryLongMethodWithManyArgu Bar bar = foo.getBar(); <--- imagine there's an extra space(s) after the semicolon instead of a line break. Make sure there's a line-break after the end of your code, and also avoid lines that have nothing - but whitespace. + but whitespace. -

Implementing Writable + + Applies pre-0.96 only + In 0.96, HBase moved to protobufs. The below section on Writables + applies to 0.94.x and previous, not to 0.96 and beyond. + + Every class returned by RegionServers must implement Writable. If you are creating a new class that needs to implement this interface, don't forget the default constructor. @@ -636,39 +1089,60 @@ Bar bar = foo.getBar(); <--- imag

Javadoc This is also a very common feedback item. Don't forget Javadoc! + Javadoc warnings are checked during precommit. If the precommit tool gives you a '-1', + please fix the javadoc issue. Your patch won't be committed if it adds such warnings. + + +

+ Findbugs + + Findbugs is used to detect common bugs pattern. As Javadoc, it is checked during + the precommit build up on Apache's Jenkins, and as with Javadoc, please fix them. + You can run findbugs locally with 'mvn findbugs:findbugs': it will generate the + findbugs files locally. Sometimes, you may have to write code smarter than + Findbugs. You can annotate your code to tell Findbugs you know what you're + doing, by annotating your class with: + @edu.umd.cs.findbugs.annotations.SuppressWarnings( + value="HE_EQUALS_USE_HASHCODE", + justification="I know what I'm doing") + + + Note that we're using the apache licensed version of the annotations.

Javadoc - Useless Defaults Don't just leave the @param arguments the way your IDE generated them. Don't do this... /** - * + * * @param bar <---- don't do this!!!! * @return <---- or this!!!! */ public Foo getFoo(Bar bar); - - ... either add something descriptive to the @param and @return lines, or just remove them. - But the preference is to add something descriptive and useful. + + ... either add something descriptive to the @param and @return lines, or just remove them. + But the preference is to add something descriptive and useful.

One Thing At A Time, Folks If you submit a patch for one thing, don't do auto-reformatting or unrelated reformatting of code on a completely - different area of code. + different area of code. - Likewise, don't add unrelated cleanup or refactorings outside the scope of your Jira. + Likewise, don't add unrelated cleanup or refactorings outside the scope of your Jira.

Ambigious Unit Tests - Make sure that you're clear about what you are testing in your unit tests and why. + Make sure that you're clear about what you are testing in your unit tests and why.

- +

ReviewBoard Larger patches should go through ReviewBoard. @@ -676,16 +1150,29 @@ Bar bar = foo.getBar(); <--- imag For more information on how to use ReviewBoard, see the ReviewBoard documentation. -

Committing Patches - Committers do this. See How To Commit in the HBase wiki. + Committers do this. See How To Commit in the Apache HBase wiki. Commiters will also resolve the Jira, typically after the patch passes a build. +

+ Committers are responsible for making sure commits do not break the build or tests + + If a committer commits a patch it is their responsibility + to make sure it passes the test suite. It is helpful + if contributors keep an eye out that their patch + does not break the hbase build and/or tests but ultimately, + a contributor cannot be expected to be up on the + particular vagaries and interconnections that occur + in a project like hbase. A committer should. + +

- + + Modified: hbase/branches/0.94/src/docbkx/external_apis.xml URL: http://svn.apache.org/viewvc/hbase/branches/0.94/src/docbkx/external_apis.xml?rev=1455996&r1=1455995&r2=1455996&view=diff ============================================================================== --- hbase/branches/0.94/src/docbkx/external_apis.xml (original) +++ hbase/branches/0.94/src/docbkx/external_apis.xml Wed Mar 13 15:20:19 2013 @@ -26,31 +26,34 @@ * limitations under the License. */ --> - External APIs - This chapter will cover access to HBase either through non-Java languages, or through custom protocols. - + Apache HBase (TM) External APIs + This chapter will cover access to Apache HBase (TM) either through non-Java languages, or through custom protocols. +

Non-Java Languages Talking to the JVM - Currently the documentation on this topic in the - HBase Wiki. + Currently the documentation on this topic in the + Apache HBase Wiki. + See also the Thrift API Javadoc.

REST - Currently most of the documentation on REST exists in the - HBase Wiki on REST. + Currently most of the documentation on REST exists in the + Apache HBase Wiki on REST (The REST gateway used to be + called 'Stargate'). There are also a nice set of blogs on How-to: Use the Apache HBase REST Interface + by Jesse Anderson.

Thrift - Currently most of the documentation on Thrift exists in the - HBase Wiki on Thrift. + Currently most of the documentation on Thrift exists in the + Apache HBase Wiki on Thrift.

Filter Language

Use Case - Note: this feature was introduced in HBase 0.92 + Note: this feature was introduced in Apache HBase 0.92 This allows the user to perform server-side filtering when accessing HBase over Thrift. The user specifies a filter via a string. The string is parsed on the server to construct the filter

@@ -407,10 +410,15 @@

- +

- + +

+ C/C++ Apache HBase Client + FB's Chip Turner wrote a pure C/C++ client. Check it out. + +