Big Data Management User Guide

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Rules and Guidelines for Hive Sources on the Blaze Engine

You can include Hive sources in an Informatica mapping that runs on the Blaze engine.

Consider the following rules and guidelines when you configure a Hive source in a mapping that runs on the Blaze engine:

Hive sources for a Blaze mapping include the TEXT, Sequence, Avro, RCfile, ORC, and Parquet storage formats.

A mapping that runs on the Blaze engine can have bucketed Hive sources and Hive ACID tables.

Hive ACID tables must be bucketed.

The Blaze engine supports Hive tables that are enabled for locking.

Hive sources can contain quoted identifiers in Hive table names, column names, and schema names.

The TEXT storage format in a Hive source for a Blaze mapping can support ASCII characters as column delimiters and the newline characters as a row separator. You cannot use hex values of ASCII characters. For example, use a semicolon (;) instead of 3B.

You can define an SQL override in the Hive source for a Blaze mapping.

The Blaze engine can read from an RCFile as a Hive source. To read from an RCFile table, you must create the table with the

SerDe

clause.

The Blaze engine can read from Hive tables that are compressed. To read from a compressed Hive table, you must set the

TBLPROPERTIES

clause.

RCFile as Hive Tables

The Blaze engine can read and write to RCFile as Hive tables. However, the Blaze engine supports only the ColumnarSerDe SerDe. In Hortonworks, the default SerDe for an RCFile is LazyBinaryColumnarSerDe. To read and write to an RCFile table, you must create the table by specifying the SerDe as

org.apache.hadoop.hive.serde2.columnar.ColumnarSerDe

For example:

CREATE TABLE TEST_RCFIle 
(id int, name string)
ROW FORMAT SERDE 
'org.apache.hadoop.hive.serde2.columnar.ColumnarSerDe' STORED AS RCFILE;

You can also set the default RCFile SerDe from the Ambari or Cloudera manager. Set the property

hive.default.rcfile.serde

org.apache.hadoop.hive.serde2.columnar.ColumnarSerDe

Compressed Hive Tables

The Blaze engine can read and write to Hive tables that are compressed. However, to read from a compressed Hive table or write to a Hive table in compressed format, you must set the

TBLPROPERTIES

clause as follows:

When you create the table, set the table properties:

TBLPROPERTIES ('property_name'='property_value')

If the table already exists, alter the table to set the table properties:

ALTER TABLE table_name SET TBLPROPERTIES ('property_name' = 'property_value');

The property name and value are not case sensitive. Depending on the file format, the table property can take different values.

The following table lists the property names and values for different file formats:

File Format	Table Property Name	Table Property Values
Avro	avro.compression	BZIP2, deflate, Snappy
ORC	orc.compress	Snappy, ZLIB
Parquet	parquet.compression	GZIP, Snappy
RCFile	rcfile.compression	Snappy, ZLIB
Sequence	sequencefile.compression	BZIP2, GZIP, LZ4, Snappy
Text	text.compression	BZIP2, GZIP, LZ4, Snappy

Unlike the Hive engine, the Blaze engine does not write data in the default ZLIB compressed format when it writes to a Hive target stored as ORC format. To write in a compressed format, alter the table to set the TBLPROPERTIES clause to use ZLIB or Snappy compression for the ORC file format.

The following text shows sample commands to create table and alter table:

Create table:

create table CBO_3T_JOINS_CUSTOMER_HIVE_SEQ_GZIP
(C_CUSTKEY DECIMAL(38,0), C_NAME STRING,C_ADDRESS STRING, 
C_PHONE STRING,C_ACCTBAL DECIMAL(10,2),
C_MKTSEGMENT VARCHAR(10),C_COMMENT vARCHAR(117))
partitioned by (C_NATIONKEY DECIMAL(38,0)) 
TBLPROPERTIES ('sequencefile.compression'='gzip') 
stored as SEQUENCEFILE;

Alter table:

ALTER TABLE table_name 
SET TBLPROPERTIES (avro.compression'='BZIP2');

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Table of Contents

Big Data Management User Guide

Big Data Management User Guide

Rules and Guidelines for Hive Sources on the Blaze Engine

Rules and Guidelines for Hive Sources on the Blaze Engine

RCFile as Hive Tables

Compressed Hive Tables