com.gpudb.protocol

Class CreateProjectionRequest

java.lang.Object

com.gpudb.protocol.CreateProjectionRequest

All Implemented Interfaces:

org.apache.avro.generic.GenericContainer, org.apache.avro.generic.IndexedRecord

public class CreateProjectionRequest
extends Object
implements org.apache.avro.generic.IndexedRecord

A set of parameters for GPUdb.createProjection(CreateProjectionRequest).

Creates a new projection of an existing table. A projection represents a subset of the columns (potentially including derived columns) of a table.

Notes:

A moving average can be calculated on a given column using the following syntax in the columnNames parameter:

'moving_average(column_name,num_points_before,num_points_after) as new_column_name'

For each record in the moving_average function's 'column_name' parameter, it computes the average over the previous 'num_points_before' records and the subsequent 'num_points_after' records.

Note that moving average relies on order_by, and order_by requires that all the data being ordered resides on the same processing node, so it won't make sense to use order_by without moving average.

Also, a projection can be created with a different shard key than the source table. By specifying shard_key, the projection will be sharded according to the specified columns, regardless of how the source table is sharded. The source table can even be unsharded or replicated.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CreateProjectionRequest.Options Optional parameters.

Constructor Summary

Constructors

Constructor and Description
CreateProjectionRequest() Constructs a CreateProjectionRequest object with default parameters.
CreateProjectionRequest(String tableName, String projectionName, List<String> columnNames, Map<String,String> options) Constructs a CreateProjectionRequest object with the specified parameters.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object obj)
Object	get(int index) This method supports the Avro framework and is not intended to be called directly by the user.
static org.apache.avro.Schema	getClassSchema() This method supports the Avro framework and is not intended to be called directly by the user.
List<String>	getColumnNames()
Map<String,String>	getOptions()
String	getProjectionName()
org.apache.avro.Schema	getSchema() This method supports the Avro framework and is not intended to be called directly by the user.
String	getTableName()
int	hashCode()
void	put(int index, Object value) This method supports the Avro framework and is not intended to be called directly by the user.
CreateProjectionRequest	setColumnNames(List<String> columnNames)
CreateProjectionRequest	setOptions(Map<String,String> options)
CreateProjectionRequest	setProjectionName(String projectionName)
CreateProjectionRequest	setTableName(String tableName)
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

CreateProjectionRequest

public CreateProjectionRequest()

Constructs a CreateProjectionRequest object with default parameters.

CreateProjectionRequest

public CreateProjectionRequest(String tableName,
                       String projectionName,
                       List<String> columnNames,
                       Map<String,String> options)

Constructs a CreateProjectionRequest object with the specified parameters.

Parameters:

tableName - Name of the existing table on which the projection is to be applied.

projectionName - Name of the projection to be created. Has the same naming restrictions as tables.

columnNames - List of columns from tableName to be included in the projection. Can include derived columns. Can be specified as aliased via the syntax 'column_name as alias'.

options - Optional parameters.

• COLLECTION_NAME: Name of a collection to which the projection is to be assigned as a child. If the collection provided is non-existent, the collection will be automatically created.
• EXPRESSION: An optional filter expression to be applied to the source table prior to the projection.
• LIMIT: The number of records to keep.
• ORDER_BY: Comma-separated list of the columns to be sorted by; e.g. 'timestamp asc, x desc'. The columns specified must be present in columnNames. If any alias is given for any column name, the alias must be used, rather than the original column name.
• MATERIALIZE_ON_GPU: If true then the columns of the projection will be cached on the GPU. Supported values:
  • TRUE
  • FALSE
  The default value is FALSE.
• TTL: Sets the TTL of the table, view, or collection specified in projectionName. The value must be the desired TTL in minutes.
• SHARD_KEY: Comma-separated list of the columns to be sharded on; e.g. 'column1, column2'. The columns specified must be present in columnNames. If any alias is given for any column name, the alias must be used, rather than the original column name.
• PERSIST: If true then the projection will be persisted as a regular table (it will not be automatically cleared unless a ttl is provided, and the table data can be modified in subsequent operations). If false then the projection will be a read-only, memory-only temporary table. Supported values:
  • TRUE
  • FALSE
  The default value is FALSE.

Method Detail

getClassSchema

public static org.apache.avro.Schema getClassSchema()

This method supports the Avro framework and is not intended to be called directly by the user.

Returns:

the schema for the class.

getTableName

public String getTableName()

Returns:

Name of the existing table on which the projection is to be applied.

setTableName

public CreateProjectionRequest setTableName(String tableName)

Parameters:

tableName - Name of the existing table on which the projection is to be applied.

Returns:

this to mimic the builder pattern.

getProjectionName

public String getProjectionName()

Returns:

Name of the projection to be created. Has the same naming restrictions as tables.

setProjectionName

public CreateProjectionRequest setProjectionName(String projectionName)

Parameters:

projectionName - Name of the projection to be created. Has the same naming restrictions as tables.

Returns:

this to mimic the builder pattern.

getColumnNames

public List<String> getColumnNames()

Returns:

List of columns from tableName to be included in the projection. Can include derived columns. Can be specified as aliased via the syntax 'column_name as alias'.

setColumnNames

public CreateProjectionRequest setColumnNames(List<String> columnNames)

Parameters:

columnNames - List of columns from tableName to be included in the projection. Can include derived columns. Can be specified as aliased via the syntax 'column_name as alias'.

Returns:

this to mimic the builder pattern.

getOptions

public Map<String,String> getOptions()

Returns:

Optional parameters.

• COLLECTION_NAME: Name of a collection to which the projection is to be assigned as a child. If the collection provided is non-existent, the collection will be automatically created.
• EXPRESSION: An optional filter expression to be applied to the source table prior to the projection.
• LIMIT: The number of records to keep.
• ORDER_BY: Comma-separated list of the columns to be sorted by; e.g. 'timestamp asc, x desc'. The columns specified must be present in columnNames. If any alias is given for any column name, the alias must be used, rather than the original column name.
• MATERIALIZE_ON_GPU: If true then the columns of the projection will be cached on the GPU. Supported values:
  • TRUE
  • FALSE
  The default value is FALSE.
• TTL: Sets the TTL of the table, view, or collection specified in projectionName. The value must be the desired TTL in minutes.
• SHARD_KEY: Comma-separated list of the columns to be sharded on; e.g. 'column1, column2'. The columns specified must be present in columnNames. If any alias is given for any column name, the alias must be used, rather than the original column name.
• PERSIST: If true then the projection will be persisted as a regular table (it will not be automatically cleared unless a ttl is provided, and the table data can be modified in subsequent operations). If false then the projection will be a read-only, memory-only temporary table. Supported values:
  • TRUE
  • FALSE
  The default value is FALSE.

setOptions

public CreateProjectionRequest setOptions(Map<String,String> options)

Parameters:

options - Optional parameters.

• COLLECTION_NAME: Name of a collection to which the projection is to be assigned as a child. If the collection provided is non-existent, the collection will be automatically created.
• EXPRESSION: An optional filter expression to be applied to the source table prior to the projection.
• LIMIT: The number of records to keep.
• ORDER_BY: Comma-separated list of the columns to be sorted by; e.g. 'timestamp asc, x desc'. The columns specified must be present in columnNames. If any alias is given for any column name, the alias must be used, rather than the original column name.
• MATERIALIZE_ON_GPU: If true then the columns of the projection will be cached on the GPU. Supported values:
  • TRUE
  • FALSE
  The default value is FALSE.
• TTL: Sets the TTL of the table, view, or collection specified in projectionName. The value must be the desired TTL in minutes.
• SHARD_KEY: Comma-separated list of the columns to be sharded on; e.g. 'column1, column2'. The columns specified must be present in columnNames. If any alias is given for any column name, the alias must be used, rather than the original column name.
• PERSIST: If true then the projection will be persisted as a regular table (it will not be automatically cleared unless a ttl is provided, and the table data can be modified in subsequent operations). If false then the projection will be a read-only, memory-only temporary table. Supported values:
  • TRUE
  • FALSE
  The default value is FALSE.

Returns:

this to mimic the builder pattern.

getSchema

public org.apache.avro.Schema getSchema()

This method supports the Avro framework and is not intended to be called directly by the user.

Specified by:

getSchema in interface org.apache.avro.generic.GenericContainer

Returns:

the schema object describing this class.

get

public Object get(int index)

This method supports the Avro framework and is not intended to be called directly by the user.

Specified by:

get in interface org.apache.avro.generic.IndexedRecord

Parameters:

index - the position of the field to get

Returns:

value of the field with the given index.

Throws:

IndexOutOfBoundsException

put

public void put(int index,
       Object value)

This method supports the Avro framework and is not intended to be called directly by the user.

Specified by:

put in interface org.apache.avro.generic.IndexedRecord

Parameters:

index - the position of the field to set

value - the value to set

Throws:

IndexOutOfBoundsException

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object