在 carbon jars 目录下包含了一个 carbondata-store-sdk-x.x.x-SNAPSHOT.jar, 这个包包含了 SDK writer 和 reader.
SDK writer 在给定的路径下写入 carbondata 和 carbonindex 文件。外部客户端可以使用该 Writer 来转换其他格式数据或实时数据来创建 carbondata 和索引文件。SDK writer 输出仅包含 carbondata和 carbonindex 文件，并不生成 metadata 文件夹。
import java.io.IOException;
import org.apache.carbondata.common.exceptions.sql.InvalidLoadOptionException;
import org.apache.carbondata.core.metadata.datatype.DataTypes;
import org.apache.carbondata.core.util.CarbonProperties;
import org.apache.carbondata.sdk.file.CarbonWriter;
import org.apache.carbondata.sdk.file.CarbonWriterBuilder;
import org.apache.carbondata.sdk.file.Field;
import org.apache.carbondata.sdk.file.Schema;
public class TestSdk {
// pass true or false while executing the main to use offheap memory or not
public static void main(String[] args) throws IOException, InvalidLoadOptionException {
if (args.length > 0 && args[0] != null) {
testSdkWriter(args[0]);
} else {
testSdkWriter("true");
}
}
public static void testSdkWriter(String enableOffheap) throws IOException, InvalidLoadOptionException {
String path = "./target/testCSVSdkWriter";
Field[] fields = new Field[2];
fields[0] = new Field("name", DataTypes.STRING);
fields[1] = new Field("age", DataTypes.INT);
Schema schema = new Schema(fields);
CarbonProperties.getInstance().addProperty("enable.offheap.sort", enableOffheap);
CarbonWriterBuilder builder = CarbonWriter.builder().outputPath(path);
CarbonWriter writer = builder.buildWriterForCSVInput(schema);
int rows = 5;
for (int i = 0; i < rows; i++) {
writer.write(new String[] { "robot" + (i % 10), String.valueOf(i) });
}
writer.close();
}
}import java.io.IOException;
import org.apache.carbondata.common.exceptions.sql.InvalidLoadOptionException;
import org.apache.carbondata.core.metadata.datatype.DataTypes;
import org.apache.carbondata.sdk.file.AvroCarbonWriter;
import org.apache.carbondata.sdk.file.CarbonWriter;
import org.apache.carbondata.sdk.file.Field;
import org.apache.avro.generic.GenericData;
import org.apache.commons.lang.CharEncoding;
import tech.allegro.schema.json2avro.converter.JsonAvroConverter;
public class TestSdkAvro {
public static void main(String[] args) throws IOException, InvalidLoadOptionException {
testSdkWriter();
}
public static void testSdkWriter() throws IOException, InvalidLoadOptionException {
String path = "./AvroCarbonWriterSuiteWriteFiles";
// Avro schema
String avroSchema =
"{" +
" \"type\" : \"record\"," +
" \"name\" : \"Acme\"," +
" \"fields\" : ["
+ "{ \"name\" : \"fname\", \"type\" : \"string\" },"
+ "{ \"name\" : \"age\", \"type\" : \"int\" }]" +
"}";
String json = "{\"fname\":\"bob\", \"age\":10}";
// conversion to GenericData.Record
JsonAvroConverter converter = new JsonAvroConverter();
GenericData.Record record = converter.convertToGenericDataRecord(
json.getBytes(CharEncoding.UTF_8), new org.apache.avro.Schema.Parser().parse(avroSchema));
try {
CarbonWriter writer = CarbonWriter.builder()
.outputPath(path)
.buildWriterForAvroInput(new org.apache.avro.Schema.Parser().parse(avroSchema));
for (int i = 0; i < 100; i++) {
writer.write(record);
}
writer.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}每个 SQL 数据类型都被映射到 SDK 的数据类型。以下是映射：
你可以直接使用 SQL 查询这些文件，而不需要创建表再在上进行查询。
SELECT * FROM carbonfile.`$Path`
在 CarbonData 仓库可以查看示例代码：DirectSQLExample
/**
* Sets the output path of the writer builder
* @param path is the absolute path where output files are written
* This method must be called when building CarbonWriterBuilder
* @return updated CarbonWriterBuilder
*/
public CarbonWriterBuilder outputPath(String path);
/**
* If set false, writes the carbondata and carbonindex files in a flat folder structure
* @param isTransactionalTable is a boolelan value
* if set to false, then writes the carbondata and carbonindex files
* in a flat folder structure.
* if set to true, then writes the carbondata and carbonindex files
* in segment folder structure..
* By default set to false.
* @return updated CarbonWriterBuilder
*/
public CarbonWriterBuilder isTransactionalTable(boolean isTransactionalTable);
/**
* to set the timestamp in the carbondata and carbonindex index files
* @param UUID is a timestamp to be used in the carbondata and carbonindex index files.
* By default set to zero.
* @return updated CarbonWriterBuilder
*/
public CarbonWriterBuilder uniqueIdentifier(long UUID);
/**
* To set the carbondata file size in MB between 1MB-2048MB
* @param blockSize is size in MB between 1MB to 2048 MB
* default value is 1024 MB
* @return updated CarbonWriterBuilder
*/
public CarbonWriterBuilder withBlockSize(int blockSize);
/**
* To set the blocklet size of carbondata file
* @param blockletSize is blocklet size in MB
* default value is 64 MB
* @return updated CarbonWriterBuilder
*/
public CarbonWriterBuilder withBlockletSize(int blockletSize);
/**
* sets the list of columns that needs to be in sorted order
* @param sortColumns is a string array of columns that needs to be sorted.
* If it is null or by default all dimensions are selected for sorting
* If it is empty array, no columns are sorted
* @return updated CarbonWriterBuilder
*/
public CarbonWriterBuilder sortBy(String[] sortColumns);
/**
* If set, create a schema file in metadata folder.
* @param persist is a boolean value, If set to true, creates a schema file in metadata folder.
* By default set to false. will not create metadata folder
* @return updated CarbonWriterBuilder
*/
public CarbonWriterBuilder persistSchemaFile(boolean persist);
/**
* sets the taskNo for the writer. SDKs concurrently running
* will set taskNo in order to avoid conflicts in file's name during write.
* @param taskNo is the TaskNo user wants to specify.
* by default it is system time in nano seconds.
* @return updated CarbonWriterBuilder
*/
public CarbonWriterBuilder taskNo(String taskNo);
/**
* To support the load options for sdk writer
* @param options key,value pair of load options.
* supported keys values are
* a. bad_records_logger_enable -- true (write into separate logs), false
* b. bad_records_action -- FAIL, FORCE, IGNORE, REDIRECT
* c. bad_record_path -- path
* d. dateformat -- same as JAVA SimpleDateFormat
* e. timestampformat -- same as JAVA SimpleDateFormat
* f. complex_delimiter_level_1 -- value to Split the complexTypeData
* g. complex_delimiter_level_2 -- value to Split the nested complexTypeData
* h. quotechar
* i. escapechar
*
* Default values are as follows.
*
* a. bad_records_logger_enable -- "false"
* b. bad_records_action -- "FAIL"
* c. bad_record_path -- ""
* d. dateformat -- "" , uses from carbon.properties file
* e. timestampformat -- "", uses from carbon.properties file
* f. complex_delimiter_level_1 -- "$"
* g. complex_delimiter_level_2 -- ":"
* h. quotechar -- "\""
* i. escapechar -- "\\"
*
* @return updated CarbonWriterBuilder
*/
public CarbonWriterBuilder withLoadOptions(Map<String, String> options);
/**
* Build a {@link CarbonWriter}, which accepts row in CSV format object
* @param schema carbon Schema object {org.apache.carbondata.sdk.file.Schema}
* @return CSVCarbonWriter
* @throws IOException
* @throws InvalidLoadOptionException
*/
public CarbonWriter buildWriterForCSVInput() throws IOException, InvalidLoadOptionException;
/**
* Build a {@link CarbonWriter}, which accepts Avro format object
* @param avroSchema avro Schema object {org.apache.avro.Schema}
* @return AvroCarbonWriter
* @throws IOException
* @throws InvalidLoadOptionException
*/
public CarbonWriter buildWriterForAvroInput() throws IOException, InvalidLoadOptionException;
/**
* Write an object to the file, the format of the object depends on the implementation
* If AvroCarbonWriter, object is of type org.apache.avro.generic.GenericData.Record
* If CSVCarbonWriter, object is of type String[]
* Note: This API is not thread safe
* @param object
* @throws IOException
*/
public abstract void write(Object object) throws IOException;
/**
* Flush and close the writer
*/
public abstract void close() throws IOException;
/**
* Create a {@link CarbonWriterBuilder} to build a {@link CarbonWriter}
*/
public static CarbonWriterBuilder builder() {
return new CarbonWriterBuilder();
}
/**
* Field Constructor
* @param name name of the field
* @param type datatype of field, specified in strings.
*/
public Field(String name, String type);
/**
* Field constructor
* @param name name of the field
* @param type datatype of the field of class DataType
*/
public Field(String name, DataType type);
/**
* construct a schema with fields
* @param fields
*/
public Schema(Field[] fields);
/**
* Create a Schema using JSON string, for example:
* [
* {"name":"string"},
* {"age":"int"}
* ]
* @param json specified as string
* @return Schema
*/
public static Schema parseJson(String json);
/**
* converts avro schema to carbon schema, required by carbonWriter
*
* @param avroSchemaString json formatted avro schema as string
* @return carbon sdk schema
*/
public static org.apache.carbondata.sdk.file.Schema getCarbonSchemaFromAvroSchema(String avroSchemaString);
SDK reader 在给定路径中读取 CarbonData 和 carbonindex 文件。 外部客户端可以使用这个 reader 来在没有创建 CarbonSession 的情况下读取 CarbonData 文件。
// 1. Create carbon reader
String path = "./testWriteFiles";
CarbonReader reader = CarbonReader
.builder(path, "_temp")
.projection(new String[]{"stringField", "shortField", "intField", "longField",
"doubleField", "boolField", "dateField", "timeField", "decimalField"})
.build();
// 2. Read data
long day = 24L * 3600 * 1000;
int i = 0;
while (reader.hasNext()) {
Object[] row = (Object[]) reader.readNextRow();
System.out.println(String.format("%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s\t",
i, row[0], row[1], row[2], row[3], row[4], row[5],
new Date((day * ((int) row[6]))), new Timestamp((long) row[7] / 1000), row[8]
));
i++;
}
// 3. Close this reader
reader.close();
Find example code at CarbonReaderExample in the CarbonData repo.
/**
* Return a new {@link CarbonReaderBuilder} instance
*
* @param tablePath table store path
* @param tableName table name
* @return CarbonReaderBuilder object
*/
public static CarbonReaderBuilder builder(String tablePath, String tableName);
/**
* Return a new CarbonReaderBuilder instance
* Default value of table name is table + tablePath + time
*
* @param tablePath table path
* @return CarbonReaderBuilder object
*/
public static CarbonReaderBuilder builder(String tablePath);
/**
* Return true if has next row
*/
public boolean hasNext();
/**
* Read and return next row object
*/
public T readNextRow();
/**
* Close reader
*/
public void close();
/**
* Construct a CarbonReaderBuilder with table path and table name
*
* @param tablePath table path
* @param tableName table name
*/
CarbonReaderBuilder(String tablePath, String tableName);
/**
* Configure the projection column names of carbon reader
*
* @param projectionColumnNames projection column names
* @return CarbonReaderBuilder object
*/
public CarbonReaderBuilder projection(String[] projectionColumnNames);
/**
* Project all Columns for carbon reader
*
* @return CarbonReaderBuilder object
* @throws IOException
*/
public CarbonReaderBuilder projectAllColumns();
/**
* Configure the transactional status of table
* If set to false, then reads the carbondata and carbonindex files from a flat folder structure.
* If set to true, then reads the carbondata and carbonindex files from segment folder structure.
* Default value is false
*
* @param isTransactionalTable whether is transactional table or not
* @return CarbonReaderBuilder object
*/
public CarbonReaderBuilder isTransactionalTable(boolean isTransactionalTable);
/**
* Configure the filter expression for carbon reader
*
* @param filterExpression filter expression
* @return CarbonReaderBuilder object
*/
public CarbonReaderBuilder filter(Expression filterExpression);
/**
* Set the access key for S3
*
* @param key the string of access key for different S3 type,like: fs.s3a.access.key
* @param value the value of access key
* @return CarbonWriterBuilder
*/
public CarbonReaderBuilder setAccessKey(String key, String value);
/**
* Set the access key for S3.
*
* @param value the value of access key
* @return CarbonWriterBuilder object
*/
public CarbonReaderBuilder setAccessKey(String value);
/**
* Set the secret key for S3
*
* @param key the string of secret key for different S3 type,like: fs.s3a.secret.key
* @param value the value of secret key
* @return CarbonWriterBuilder object
*/
public CarbonReaderBuilder setSecretKey(String key, String value);
/**
* Set the secret key for S3
*
* @param value the value of secret key
* @return CarbonWriterBuilder object
*/
public CarbonReaderBuilder setSecretKey(String value);
/**
* Set the endpoint for S3
*
* @param key the string of endpoint for different S3 type,like: fs.s3a.endpoint
* @param value the value of endpoint
* @return CarbonWriterBuilder object
*/
public CarbonReaderBuilder setEndPoint(String key, String value);
/**
* Set the endpoint for S3
*
* @param value the value of endpoint
* @return CarbonWriterBuilder object
*/
public CarbonReaderBuilder setEndPoint(String value);
/**
* Build CarbonReader
*
* @param <T>
* @return CarbonReader
* @throws IOException
* @throws InterruptedException
*/
public <T> CarbonReader<T> build();
/**
* Read schema file and return the schema
*
* @param schemaFilePath complete path including schema file name
* @return schema object
* @throws IOException
*/
public static Schema readSchemaInSchemaFile(String schemaFilePath);
/**
* Read carbondata file and return the schema
*
* @param dataFilePath complete path including carbondata file name
* @return Schema object
* @throws IOException
*/
public static Schema readSchemaInDataFile(String dataFilePath);
/**
* Read carbonindex file and return the schema
*
* @param indexFilePath complete path including index file name
* @return schema object
* @throws IOException
*/
public static Schema readSchemaInIndexFile(String indexFilePath);
/**
* construct a schema with fields
* @param fields
*/
public Schema(Field[] fields);
/**
* construct a schema with List<ColumnSchema>
*
* @param columnSchemaList column schema list
*/
public Schema(List<ColumnSchema> columnSchemaList);
/**
* Create a Schema using JSON string, for example:
* [
* {"name":"string"},
* {"age":"int"}
* ]
* @param json specified as string
* @return Schema
*/
public static Schema parseJson(String json);
/**
* Sort the schema order as original order
*
* @return Schema object
*/
public Schema asOriginOrder();
/**
* Field Constructor
* @param name name of the field
* @param type datatype of field, specified in strings.
*/
public Field(String name, String type);
/**
* Construct Field from ColumnSchema
*
* @param columnSchema ColumnSchema, Store the information about the column meta data
*/
public Field(ColumnSchema columnSchema);
Find S3 example code at SDKS3Example in the CarbonData repo.
/**
* This method will be responsible to get the instance of CarbonProperties class
*
* @return carbon properties instance
*/
public static CarbonProperties getInstance();
/**
* This method will be used to add a new property
*
* @param key is a property name to set for carbon.
* @param value is valid parameter corresponding to property.
* @return CarbonProperties object
*/
public CarbonProperties addProperty(String key, String value);
/**
* This method will be used to get the property value. If property is not
* present, then it will return the default value.
*
* @param key is a property name to get user specified value.
* @return properties value for corresponding key. If not set, then returns null.
*/
public String getProperty(String key);
/**
* This method will be used to get the property value. If property is not
* present, then it will return the default value.
*
* @param key is a property name to get user specified value..
* @param defaultValue used to be returned by function if corrosponding key not set.
* @return properties value for corresponding key. If not set, then returns specified defaultValue.
*/
public String getProperty(String key, String defaultValue);
Reference : list of carbon properties