com.yahoo.bard.webservice.sql

Class DruidQueryToSqlConverter

java.lang.Object

com.yahoo.bard.webservice.sql.DruidQueryToSqlConverter

public class DruidQueryToSqlConverter
extends Object

Default implementation of converting a DruidQuery into a sql query.

Field Summary

Fields

Modifier and Type	Field and Description
static int	NO_LIMIT
static int	NO_OFFSET

Constructor Summary

Constructors

Constructor and Description
DruidQueryToSqlConverter(CalciteHelper calciteHelper) Constructs the default converter.

Method Summary

Modifier and Type	Method and Description
protected BiFunction<Aggregation,ApiToFieldMapper,Optional<SqlAggregation>>	buildDruidSqlTypeConverter() Builds a converter between druid and sql aggregations.
String	buildSqlQuery(DruidAggregationQuery<?> druidQuery, ApiToFieldMapper apiToFieldMapper) Builds the druid query as sql and returns it as a string.
protected SqlTimeConverter	buildSqlTimeConverter() Builds a time converter to designating how to translate between druid and sql time information.
protected List<org.apache.calcite.rex.RexNode>	getAllGroupByColumns(org.apache.calcite.tools.RelBuilder builder, DruidAggregationQuery<?> druidQuery, ApiToFieldMapper apiToFieldMapper, String timestampColumn) Collects all the time columns and dimensions to be grouped on.
protected List<org.apache.calcite.tools.RelBuilder.AggCall>	getAllQueryAggregations(org.apache.calcite.tools.RelBuilder builder, DruidAggregationQuery<?> druidQuery, ApiToFieldMapper apiToFieldMapper) Find all druid aggregations and convert them to RelBuilder.AggCall.
protected org.apache.calcite.rex.RexNode	getAllWhereFilters(org.apache.calcite.tools.RelBuilder builder, DruidAggregationQuery<?> druidQuery, ApiToFieldMapper apiToFieldMapper, String timestampColumn) Returns the RexNode used to filter the druidQuery.
protected Collection<org.apache.calcite.rex.RexNode>	getHavingFilter(org.apache.calcite.tools.RelBuilder builder, DruidAggregationQuery<?> druidQuery, ApiToFieldMapper apiToFieldMapper) Gets the collection of having filters to be applied from the druid query.
protected int	getLimit(DruidAggregationQuery<?> druidQuery) Gets the number of rows to limit results to for a Group by Query.
protected List<org.apache.calcite.rex.RexNode>	getSort(org.apache.calcite.tools.RelBuilder builder, DruidAggregationQuery<?> druidQuery, ApiToFieldMapper apiToFieldMapper, String timestampColumn) Finds the sorting for a druid query.
SqlTimeConverter	getTimeConverter()
protected boolean	isValidQuery(DruidQuery<?> druidQuery) Determines whether or not a query is able to be processed using the Sql backend.
protected String	writeSql(org.apache.calcite.sql.pretty.SqlPrettyWriter sqlWriter, org.apache.calcite.rel.rel2sql.RelToSqlConverter relToSql, org.apache.calcite.rel.RelNode query) Converts a RelBuilder into a sql string.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

NO_OFFSET

public static final int NO_OFFSET

See Also:

Constant Field Values

NO_LIMIT

public static final int NO_LIMIT

See Also:

Constant Field Values

Constructor Detail

DruidQueryToSqlConverter

public DruidQueryToSqlConverter(CalciteHelper calciteHelper)

Constructs the default converter. TODO could make an interface with isValidQuery(DruidQuery) and buildSqlQuery(DruidAggregationQuery, ApiToFieldMapper). Maybe make it a generic more generic like "DruidQueryConverter<T>"

Parameters:

calciteHelper - The calcite helper for this database.

Method Detail

buildSqlTimeConverter

protected SqlTimeConverter buildSqlTimeConverter()

Builds a time converter to designating how to translate between druid and sql time information.

Returns:

a new time converter.

buildDruidSqlTypeConverter

protected BiFunction<Aggregation,ApiToFieldMapper,Optional<SqlAggregation>> buildDruidSqlTypeConverter()

Builds a converter between druid and sql aggregations.

Returns:

a new druid to sql aggregation converter.

isValidQuery

protected boolean isValidQuery(DruidQuery<?> druidQuery)

Determines whether or not a query is able to be processed using the Sql backend.

Parameters:

druidQuery - The query to check if is able to be processed.

Returns:

true if a valid query, else false.

buildSqlQuery

public String buildSqlQuery(DruidAggregationQuery<?> druidQuery,
                            ApiToFieldMapper apiToFieldMapper)

Builds the druid query as sql and returns it as a string.

Parameters:

druidQuery - The query to convert to sql.

apiToFieldMapper - The mapping between api and physical names for the query.

Returns:

the sql equivalent of the query.

getLimit

protected int getLimit(DruidAggregationQuery<?> druidQuery)

Gets the number of rows to limit results to for a Group by Query. Otherwise no limit is applied.

Parameters:

druidQuery - The query to get the row limit from.

Returns:

the number of rows to include in the results.

getSort

protected List<org.apache.calcite.rex.RexNode> getSort(org.apache.calcite.tools.RelBuilder builder,
                                                       DruidAggregationQuery<?> druidQuery,
                                                       ApiToFieldMapper apiToFieldMapper,
                                                       String timestampColumn)

Finds the sorting for a druid query.

Parameters:

builder - The RelBuilder created with Calcite.

druidQuery - The query to find the sorting from.

apiToFieldMapper - The mapping from api to physical names.

timestampColumn - The name of the timestamp column in the database.

Returns:

a collection of rexnodes to apply sorts in calcite.

getAllWhereFilters

protected org.apache.calcite.rex.RexNode getAllWhereFilters(org.apache.calcite.tools.RelBuilder builder,
                                                            DruidAggregationQuery<?> druidQuery,
                                                            ApiToFieldMapper apiToFieldMapper,
                                                            String timestampColumn)

Returns the RexNode used to filter the druidQuery.

Parameters:

builder - The RelBuilder created with Calcite.

druidQuery - The query from which to find filter all the filters for.

apiToFieldMapper - The mapping from api to physical names.

timestampColumn - The name of the timestamp column in the database.

Returns:

the combined RexNodes that should be filtered on.

getHavingFilter

protected Collection<org.apache.calcite.rex.RexNode> getHavingFilter(org.apache.calcite.tools.RelBuilder builder,
                                                                     DruidAggregationQuery<?> druidQuery,
                                                                     ApiToFieldMapper apiToFieldMapper)

Gets the collection of having filters to be applied from the druid query.

Parameters:

builder - The RelBuilder created with Calcite.

druidQuery - The query to find the having filter from.

apiToFieldMapper - The mapping from api to physical name.

Returns:

the collection of equivalent filters for calcite.

getAllQueryAggregations

protected List<org.apache.calcite.tools.RelBuilder.AggCall> getAllQueryAggregations(org.apache.calcite.tools.RelBuilder builder,
                                                                                    DruidAggregationQuery<?> druidQuery,
                                                                                    ApiToFieldMapper apiToFieldMapper)

Find all druid aggregations and convert them to RelBuilder.AggCall.

Parameters:

builder - The RelBuilder created with Calcite.

druidQuery - The druid query to get the aggregations of.

apiToFieldMapper - The mapping from api to physical name.

Returns:

the list of aggregations.

getAllGroupByColumns

protected List<org.apache.calcite.rex.RexNode> getAllGroupByColumns(org.apache.calcite.tools.RelBuilder builder,
                                                                    DruidAggregationQuery<?> druidQuery,
                                                                    ApiToFieldMapper apiToFieldMapper,
                                                                    String timestampColumn)

Collects all the time columns and dimensions to be grouped on.

Parameters:

builder - The RelBuilder created with Calcite.

druidQuery - The query to find grouping columns from.

apiToFieldMapper - The mapping from api to physical name.

timestampColumn - The name of the timestamp column in the database.

Returns:

all columns which should be grouped on.

writeSql

protected String writeSql(org.apache.calcite.sql.pretty.SqlPrettyWriter sqlWriter,
                          org.apache.calcite.rel.rel2sql.RelToSqlConverter relToSql,
                          org.apache.calcite.rel.RelNode query)

Converts a RelBuilder into a sql string.

Parameters:

sqlWriter - The writer to be used when translating the RelNode to sql.

relToSql - The converter from RelNode to SqlNode.

query - The RelNode representing the query.

Returns:

the sql string built by the RelBuilder.

getTimeConverter

public SqlTimeConverter getTimeConverter()