commit | 3f1d0472243f25eacf611b12a5e1150294683957 | [log] [tgz] |
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author | norbert.luksa <norbert.luksa@cloudera.com> | Wed Oct 02 09:50:48 2019 +0200 |
committer | Impala Public Jenkins <impala-public-jenkins@cloudera.com> | Mon Oct 21 20:23:56 2019 +0000 |
tree | c7368b8f106cd487391d033703e7aef438c1f481 | |
parent | 378a108ecc3c70a73140155324249fa124bf7bdd [diff] |
IMPALA-6501: Optimize count(star) for Kudu scans IMPALA-5036 added an optimisation for count(star) in Parquet scans that avoids materialising dummy rows. This change provides similar optimization for Kudu tables. Instead of materializing empty rows when computing count star, we use the NumRows field from the Kudu API. The Kudu scanner tuple is modified to have one slot into which we will write the num rows statistic. The aggregate function is changed from count to a special sum function that gets initialized to 0. Tests: * Added end-to-end tests ̣* Added planner tests * Run performance tests on tpch.lineitem Kudu table with 25 set as scaling factor, on 1 node, with mt_dop set to 1, just to measure the speedup gained when scanning. Counting the rows before the optimization took around 400ms, and around 170ms after. Change-Id: Ic99e0f954d0ca65779bd531ca79ace1fcb066fb9 Reviewed-on: http://gerrit.cloudera.org:8080/14347 Reviewed-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com> Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
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:
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.
Impala only supports Linux at the moment.
This distribution uses cryptographic software and may be subject to export controls. Please refer to EXPORT_CONTROL.md for more information.
See bin/bootstrap_build.sh.
Impala can be built with pre-built components or components downloaded from S3. 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.
Location | Purpose |
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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. |
Environment variable | Default value | Description |
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IMPALA_HOME | Top level Impala directory | |
IMPALA_TOOLCHAIN | “${IMPALA_HOME}/toolchain” | Native toolchain directory (for compilers, libraries, etc.) |
SKIP_TOOLCHAIN_BOOTSTRAP | “false” | Skips downloading the toolchain any python dependencies if “true” |
CDH_BUILD_NUMBER | Identifier to indicate the CDH build number | |
CDH_COMPONENTS_HOME | “${IMPALA_HOME}/toolchain/cdh_components-${CDH_BUILD_NUMBER}” | Location of the CDH components within the 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-0.1.19/dist/sqlparse-0.1.19-py2 |
Environment variable | Default value | Description |
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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 | “${IMPALA_HOME}/common” | Common code (thrift, function registry) |
Environment variable | Default value | Description |
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IMPALA_BUILD_THREADS | “8” or set to number of processors by default. | Used for make -j and distcc -j settings. |
IMPALA_MAKE_FLAGS | "" | Any extra settings to pass to make. Also used when copying udfs / udas into HDFS. |
USE_SYSTEM_GCC | “0” | If set to any other value, directs cmake to not set GCC_ROOT, CMAKE_C_COMPILER, CMAKE_CXX_COMPILER, as well as setting TOOLCHAIN_LINK_FLAGS |
IMPALA_CXX_COMPILER | “default” | Used by cmake (cmake_modules/toolchain and clang_toolchain.cmake) to select gcc / clang |
USE_GOLD_LINKER | “true” | Directs backend cmake to use gold. |
IS_OSX | “false” | (Experimental) currently only used to disable Kudu. |
Environment variable | Default value | Description |
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HADOOP_HOME | “${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-${IMPALA_HIVE_VERSION}/” | |
HBASE_HOME | “${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}” |