[jira] [Created] (KYLIN-4757) Impossible precision for decimal datatype in kylin if the source column is numeric in postgres

["André Luís da Rosa de Lima (Jira)" <ji...@apache.org>]

André Luís da Rosa de Lima created KYLIN-4757:
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             Summary: Impossible precision for decimal datatype in kylin if the source column is numeric in postgres
                 Key: KYLIN-4757
                 URL: https://issues.apache.org/jira/browse/KYLIN-4757
             Project: Kylin
          Issue Type: Bug
          Components: RDBMS Source
    Affects Versions: v4.0.0-alpha
            Reporter: André Luís da Rosa de Lima


Using Postgres as data source, columns of datatype numeric without a explicitly set precision and scale become "decimal(256)" in kylin. 256 comes from the value of "kylin.source.hive.default-varchar-precision" (despite using jdbc as datasource)

The problem can be fixed in "org.apache.kylin.source.jdbc.extensible.JdbcExplorer" class ([https://github.com/apache/kylin/blob/kylin-4.0.0-alpha/source-jdbc/src/main/java/org/apache/kylin/source/jdbc/extensible/JdbcExplorer.java#L111)]

I fixed it by modifying the following part in the source file starting after line 111:
{code:java}
int precision = (SqlUtil.isPrecisionApplicable(kylinType) && csize > 0) ? csize : -1;                precision = Math.min(precision, KylinConfig.getInstanceFromEnv().getDefaultVarcharPrecision());                
int scale = (SqlUtil.isScaleApplicable(kylinType) && digits > 0) ? digits : -1;
{code}
to this:

 
{code:java}
int precision = (SqlUtil.isPrecisionApplicable(kylinType) && csize > 0) ? csize : -1;

int maxPrecision = precision;if (kylinType.equals("char")) {
    maxPrecision = KylinConfig.getInstanceFromEnv().getDefaultCharPrecision();
} else if (kylinType.equals("varchar")) {
    maxPrecision = KylinConfig.getInstanceFromEnv().getDefaultVarcharPrecision();
} else if ((kylinType.equals("decimal") || kylinType.equals("numeric"))) {
    maxPrecision = KylinConfig.getInstanceFromEnv().getDefaultDecimalPrecision();
}
precision = Math.min(precision, maxPrecision);

int scale = (SqlUtil.isScaleApplicable(kylinType) && digits > 0) ? digits : -1;
{code}
 

 



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