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5e9b4e2fd2
Equivalent class is used to get the equivalencies between slots. It is ill-defined and the current implementation is inefficient. This patch removes it and directly uses the information from the value transfer graph instead. Value transfer graph is reimplemented using Tarjan's strongly connected component algorithm and BFS with adjacency lists to speed up on both condensed and sparse graphs. Testing: It passes the existing tests. In planner tests the equivalence between SCC-condensed graph and uncondensed graph is checked. A test case is added for a helper class IntArrayList. An outer-join edge case is added in planner test. On a query with 1800 union operations, the equivalence class computation time is reduced from 7m57s to 65ms and the planning time is reduced from 8m5s to 13s. Change-Id: If4cb1d8be46efa8fd61a97048cc79dabe2ffa51a Reviewed-on: http://gerrit.cloudera.org:8080/8317 Reviewed-by: Alex Behm <alex.behm@cloudera.com> Tested-by: Impala Public Jenkins
Welcome to Impala
Lightning-fast, distributed SQL queries for petabytes of data stored in Apache Hadoop clusters.
Impala is a modern, massively-distributed, massively-parallel, C++ query engine that lets you analyze, transform and combine data from a variety of data sources:
- Best of breed performance and scalability.
- Support for data stored in HDFS, Apache HBase and Amazon S3.
- Wide analytic SQL support, including window functions and subqueries.
- On-the-fly code generation using LLVM to generate CPU-efficient code tailored specifically to each individual query.
- Support for the most commonly-used Hadoop file formats, including the Apache Parquet project.
- Apache-licensed, 100% open source.
More about Impala
To learn more about Impala as a business user, or to try Impala live or in a VM, please visit the Impala homepage.
If you are interested in contributing to Impala as a developer, or learning more about Impala's internals and architecture, visit the Impala wiki.
Supported Platforms
Impala only supports Linux at the moment.
Export Control Notice
This distribution uses cryptographic software and may be subject to export controls. Please refer to EXPORT_CONTROL.md for more information.
Build Instructions
See bin/bootstrap_build.sh.
Detailed Build Notes
Impala can be built with pre-built components, downloaded from S3, or can be built with an in-place toolchain located in the thirdparty directory (not recommended). The components needed to build Impala are Apache Hadoop, Hive, HBase, and Sentry. 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 | "${IMPALA_HOME}/toolchain" | Native toolchain directory (for compilers, libraries, etc.) |
| SKIP_TOOLCHAIN_BOOTSTRAP | "false" | Skips downloading the toolchain any python dependencies if "true" |
| CDH_COMPONENTS_HOME | "${IMPALA_HOME}/toolchain/cdh_components" OR "${IMPALA_HOME}/thirdparty" (if detected) | If a thirdparty directory is present, components found here will override anything in IMPALA_TOOLCHAIN. |
| CDH_MAJOR_VERSION | "5" | 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" "${HIVE_HOME}/lib/py" "${IMPALA_HOME}/shell/ext-py/prettytable-0.7.1/dist/prettytable-0.7.1" "${IMPALA_HOME}/shell/ext-py/sasl-0.1.1/dist/sasl-0.1.1-py2.7-linux-x "${IMPALA_HOME}/shell/ext-py/sqlparse-0.1.14/dist/sqlparse-0.1.14-py2 |
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 | "${IMPALA_HOME}/common" | Common code (thrift, function registry) |
Various Compilation Settings
| Environment variable | Default value | Description |
|---|---|---|
| IMPALA_BUILD_THREADS | "8" or set to number of processors by default. | Used for make -j and distcc -j settings. |
| IMPALA_MAKE_FLAGS | "" | Any extra settings to pass to make. Also used when copying udfs / udas into HDFS. |
| USE_SYSTEM_GCC | "0" | If set to any other value, directs cmake to not set GCC_ROOT, CMAKE_C_COMPILER, CMAKE_CXX_COMPILER, as well as setting TOOLCHAIN_LINK_FLAGS |
| IMPALA_CXX_COMPILER | "default" | Used by cmake (cmake_modules/toolchain and clang_toolchain.cmake) to select gcc / clang |
| USE_GOLD_LINKER | "true" | Directs backend cmake to use gold. |
| IS_OSX | "false" | (Experimental) currently only used to disable Kudu. |
Dependencies
| Environment variable | Default value | Description |
|---|---|---|
| HADOOP_HOME | "${CDH_COMPONENTS_HOME}/hadoop-${IMPALA_HADOOP_VERSION}/" | Used to locate Hadoop |
| HADOOP_INCLUDE_DIR | "${HADOOP_HOME}/include" | For 'hdfs.h' |
| HADOOP_LIB_DIR | "${HADOOP_HOME}/lib" | For 'libhdfs.a' or 'libhdfs.so' |
| HIVE_HOME | "${CDH_COMPONENTS_HOME}/{hive-${IMPALA_HIVE_VERSION}/" | |
| HIVE_SRC_DIR | "${HIVE_HOME}/src" | Used to find Hive thrift files. |
| HBASE_HOME | "${CDH_COMPONENTS_HOME}/hbase-${IMPALA_HBASE_VERSION}/" | |
| SENTRY_HOME | "${CDH_COMPONENTS_HOME}/sentry-${IMPALA_SENTRY_VERSION}/" | Used to setup test data |
| THRIFT_HOME | "${IMPALA_TOOLCHAIN}/thrift-${IMPALA_THRIFT_VERSION}" |