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This patch uses the "external data source" mechanism in Impala to
implement data source for querying JDBC.
It has some limitations due to the restrictions of "external data
source":
- It is not distributed, e.g, fragment is unpartitioned. The queries
are executed on coordinator.
- Queries which read following data types from external JDBC tables
are not supported:
BINARY, CHAR, DATETIME, and COMPLEX.
- Only support binary predicates with operators =, !=, <=, >=,
<, > to be pushed to RDBMS.
- Following data types are not supported for predicates:
DECIMAL, TIMESTAMP, DATE, and BINARY.
- External tables with complex types of columns are not supported.
- Support is limited to the following databases:
MySQL, Postgres, Oracle, MSSQL, H2, DB2, and JETHRO_DATA.
- Catalog V2 is not supported (IMPALA-7131).
- DataSource objects are not persistent (IMPALA-12375).
Additional fixes are planned on top of this patch.
Source files under jdbc/conf, jdbc/dao and jdbc/exception are
replicated from Hive JDBC Storage Handler.
In order to query the RDBMS tables, the following steps should be
followed (note that existing data source table will be rebuilt):
1. Make sure the Impala cluster has been started.
2. Copy the jar files of JDBC drivers and the data source library into
HDFS.
${IMPALA_HOME}/testdata/bin/copy-ext-data-sources.sh
3. Create an `alltypes` table in the Postgres database.
${IMPALA_HOME}/testdata/bin/load-ext-data-sources.sh
4. Create data source tables (alltypes_jdbc_datasource and
alltypes_jdbc_datasource_2).
${IMPALA_HOME}/bin/impala-shell.sh -f\
${IMPALA_HOME}/testdata/bin/create-ext-data-source-table.sql
5. It's ready to run query to access data source tables created
in last step. Don't need to restart Impala cluster.
Testing:
- Added unit-test for Postgres and ran unit-test with JDBC driver
postgresql-42.5.1.jar.
- Ran manual unit-test for MySql with JDBC driver
mysql-connector-j-8.1.0.jar.
- Ran core tests successfully.
Change-Id: I8244e978c7717c6f1452f66f1630b6441392e7d2
Reviewed-on: http://gerrit.cloudera.org:8080/17842
Reviewed-by: Wenzhe Zhou <wzhou@cloudera.com>
Reviewed-by: Kurt Deschler <kdeschle@cloudera.com>
Reviewed-by: Riza Suminto <riza.suminto@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
39 lines
1.5 KiB
XML
39 lines
1.5 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!--
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Licensed to the Apache Software Foundation (ASF) under one
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or more contributor license agreements. See the NOTICE file
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distributed with this work for additional information
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regarding copyright ownership. The ASF licenses this file
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to you under the Apache License, Version 2.0 (the
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"License"); you may not use this file except in compliance
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with the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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<project xmlns="http://maven.apache.org/POM/4.0.0"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
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<parent>
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<groupId>org.apache.impala</groupId>
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<artifactId>impala-parent</artifactId>
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<version>4.4.0-SNAPSHOT</version>
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</parent>
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<modelVersion>4.0.0</modelVersion>
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<artifactId>impala-data-source</artifactId>
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<name>Apache Impala External Data Source</name>
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<packaging>pom</packaging>
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<modules>
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<module>api</module>
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<module>sample</module>
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<module>test</module>
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<module>jdbc</module>
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</modules>
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</project>
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