README-build.md

This document introduces the Impala project layout and some key configuration variables. Beware that it may become stale over time as the project evolves.

Detailed Build Notes

Impala can be built with pre-built components or components downloaded from S3. The components needed to build Impala are Apache Hadoop, Hive, and HBase. If you need to manually override the locations or versions of these components, you can do so through the environment variables and scripts listed below.

Scripts and directories

Location	Purpose
bin/impala-config.sh	This script must be sourced to setup all environment variables properly to allow other scripts to work
bin/impala-config-local.sh	A script can be created in this location to set local overrides for any environment variables
bin/impala-config-branch.sh	A version of the above that can be checked into a branch for convenience.
bin/bootstrap_build.sh	A helper script to bootstrap some of the build requirements.
bin/bootstrap_development.sh	A helper script to bootstrap a developer environment. Please read it before using.
be/build/	Impala build output goes here.
be/generated-sources/	Thrift and other generated source will be found here.

Build Related Variables

Environment variable	Default value	Description
IMPALA_HOME		Top level Impala directory
IMPALA_TOOLCHAIN	"${IMPALA_HOME}/toolchain"	Native toolchain directory (for compilers, libraries, etc.)
SKIP_TOOLCHAIN_BOOTSTRAP	"false"	Skips downloading the toolchain any python dependencies if "true"
CDP_BUILD_NUMBER		Identifier to indicate the CDP build number
CDP_COMPONENTS_HOME	"${IMPALA_HOME}/toolchain/cdp_components-${CDP_BUILD_NUMBER}"	Location of the CDP components within the toolchain.
CDH_MAJOR_VERSION	"7"	Identifier used to uniqueify paths for potentially incompatible component builds.
IMPALA_CONFIG_SOURCED	"1"	Set by ${IMPALA_HOME}/bin/impala-config.sh (internal use)
JAVA_HOME	"/usr/lib/jvm/${JAVA_VERSION}"	Used to locate Java
JAVA_VERSION	"java-7-oracle-amd64"	Can override to set a local Java version.
JAVA	"${JAVA_HOME}/bin/java"	Java binary location.
CLASSPATH		See bin/set-classpath.sh for details.
PYTHONPATH	Will be changed to include: "${IMPALA_HOME}/shell/gen-py" "${IMPALA_HOME}/testdata" "${THRIFT_HOME}/python/lib/python2.7/site-packages" "${HIVE_HOME}/lib/py"

Source Directories for Impala

Environment variable	Default value	Description
IMPALA_BE_DIR	"${IMPALA_HOME}/be"	Backend directory. Build output is also stored here.
IMPALA_FE_DIR	"${IMPALA_HOME}/fe"	Frontend directory
IMPALA_COMMON_DIR	"${IMPALA_HOME}/common"	Common code (thrift, function registry)

Various Compilation Settings

Environment variable	Default value	Description
IMPALA_BUILD_THREADS	"8" or set to number of processors by default.	Used for make -j and distcc -j settings.
IMPALA_MAKE_FLAGS	""	Any extra settings to pass to make. Also used when copying udfs / udas into HDFS.
USE_SYSTEM_GCC	"0"	If set to any other value, directs cmake to not set GCC_ROOT, CMAKE_C_COMPILER, CMAKE_CXX_COMPILER, as well as setting TOOLCHAIN_LINK_FLAGS
IMPALA_CXX_COMPILER	"default"	Used by cmake (cmake_modules/toolchain and clang_toolchain.cmake) to select gcc / clang
USE_GOLD_LINKER	"true"	Directs backend cmake to use gold.
IS_OSX	"false"	(Experimental) currently only used to disable Kudu.

Dependencies

Environment variable	Default value	Description
HADOOP_HOME	"${CDP_COMPONENTS_HOME}/hadoop-${IMPALA_HADOOP_VERSION}/"	Used to locate Hadoop
HADOOP_INCLUDE_DIR	"${HADOOP_HOME}/include"	For 'hdfs.h'
HADOOP_LIB_DIR	"${HADOOP_HOME}/lib"	For 'libhdfs.a' or 'libhdfs.so'
HIVE_HOME	"${CDP_COMPONENTS_HOME}/{hive-${IMPALA_HIVE_VERSION}/"
HBASE_HOME	"${CDP_COMPONENTS_HOME}/hbase-${IMPALA_HBASE_VERSION}/"
THRIFT_HOME	"${IMPALA_TOOLCHAIN}/thrift-${IMPALA_THRIFT_VERSION}"