Pavel Benes created SQOOP-3014:
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Summary: Sqoop with HCatalog import loose precision for large
numbers that does not fit into double
Key: SQOOP-3014
URL: https://issues.apache.org/jira/browse/SQOOP-3014
Project: Sqoop
Issue Type: Bug
Components: hive-integration
Affects Versions: 1.4.6
Reporter: Pavel Benes
Priority: Critical
When using sqoop with HCatalog to import data from JDBC (I have tried Oracle11)
all numbers that does not fit into double are loosing its precision or are
distorted.
Steps to reproduce:
1) Create test table in Oracle and fill it with test data
{code}
CREATE TABLE TEST_SQOOP_ERROR(ID VARCHAR(10), TYPE_NUMBER DECIMAL(22,5))
INSERT INTO MMDINGEST.TEST_SQOOP_ERROR(ID, TYPE_NUMBER) VALUES ( 'row-1',
454018528782.42006329)
INSERT INTO MMDINGEST.TEST_SQOOP_ERROR(ID, TYPE_NUMBER) VALUES ( 'row-2',
87658675864540185.123456789123456789)
INSERT INTO MMDINGEST.TEST_SQOOP_ERROR(ID, TYPE_NUMBER) VALUES ( 'row-3',
87658675864540185.12345)
INSERT INTO MMDINGEST.TEST_SQOOP_ERROR(ID, TYPE_NUMBER) VALUES ( 'row-4',
87658675864540185.123)
INSERT INTO MMDINGEST.TEST_SQOOP_ERROR(ID, TYPE_NUMBER) VALUES ( 'row-5',
7658675864540185.12345)
INSERT INTO MMDINGEST.TEST_SQOOP_ERROR(ID, TYPE_NUMBER) VALUES ( 'row-6',
7658675864540185.123456789)
INSERT INTO MMDINGEST.TEST_SQOOP_ERROR(ID, TYPE_NUMBER) VALUES ( 'row-7',
658675864540185.12345)
INSERT INTO MMDINGEST.TEST_SQOOP_ERROR(ID, TYPE_NUMBER) VALUES ( 'row-8',
58675864540185.12345)
INSERT INTO MMDINGEST.TEST_SQOOP_ERROR(ID, TYPE_NUMBER) VALUES ( 'row-9',
8675864540185.12345)
INSERT INTO MMDINGEST.TEST_SQOOP_ERROR(ID, TYPE_NUMBER) VALUES ( 'row-10',
675864540185.12345)
INSERT INTO MMDINGEST.TEST_SQOOP_ERROR(ID, TYPE_NUMBER) VALUES ( 'row-11',
75864540185.12345)
INSERT INTO MMDINGEST.TEST_SQOOP_ERROR(ID, TYPE_NUMBER) VALUES ( 'row-12',
35864540185.12345)
INSERT INTO MMDINGEST.TEST_SQOOP_ERROR(ID, TYPE_NUMBER) VALUES ( 'row-13',
5864540185.12345)
{code}
2) Create table in Hive database
{code}
CREATE TABLE pbe_test_sqoop_error(id string, type_number decimal(22,5)) STORED
AS ORC;
{code}
3) Import data from Oracle to Hive using sqoop
{code}
export HADOOP_CLASSPATH=/opt/mantis/jdbc/oracle-11.2/ojdbc6.jar
sqoop import -connect jdbc:oracle:thin:@//54.40.19.81:1521/XE --username XXX
--password XXX --hcatalog-database default --hcatalog-table
pbe_test_sqoop_error --driver oracle.jdbc.OracleDriver --query 'SELECT id,
type_number FROM MMDINGEST.TEST_SQOOP_ERROR WHERE $CONDITIONS' -m 1
{code}
4) Display data from Hive table
{code}
hive> select * from pbe_test_sqoop_error;
OK
row-1 454018528782.42004
row-2 87658675864540192
row-3 87658675864540192
row-4 87658675864540192
row-5 7658675864540185
row-6 7658675864540185
row-7 658675864540185.125
row-8 58675864540185.125
row-9 8675864540185.12305
row-10 675864540185.12341
row-11 75864540185.12344
row-12 35864540185.12345
row-13 5864540185.12345
Time taken: 0.455 seconds, Fetched: 13 row(s)
{code}
Only the values at line 1, 12, 13 are correct. At the lines 2-4 even the part
of the number before dot is wrong. All looks correctly in Oracle as can be seen
on the attached screenshot.
The problem seems to be in the java class
https://www.codatlas.com/github.com/apache/sqoop/branch-1.4.6/src/java/org/apache/sqoop/mapreduce/hcat/SqoopHCatImportHelper.java
starting at line 437.
{code}
} else if (hfsType == HCatFieldSchema.Type.DECIMAL) {
BigDecimal bd = new BigDecimal(n.doubleValue(),
MathContext.DECIMAL128);
return HiveDecimal.create(bd);
}
{code}
all numbers, even those that are stored in BigDecimal are squeezed through
double which leads to the precision lost The same issue could be at some places
when working with large numbers.
The following code fixes this issue:
{code}
} else if (hfsType == HCatFieldSchema.Type.DECIMAL) {
BigDecimal bd = val instanceof BigDecimal ? (BigDecimal) val : new
BigDecimal(n.doubleValue(), MathContext.DECIMAL128);
return HiveDecimal.create(bd);
}
{code} .
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