org.apache.drill.exec.planner.index

Interface FunctionalIndexInfo

public interface FunctionalIndexInfo

FunctionalIndexInfo is to collect Functional fields in IndexDescriptor, derive information needed for index plan, e.g. convert and rewrite filter, columns, and rowtype on index scan that involve functional index. In case different store might have different way to rename expression in index table, we allow storage plugin

Method Summary

Modifier and Type	Method and Description
Set<SchemaPath>	allNewSchemaPaths()
Set<SchemaPath>	allPathsInFunction()
Map<LogicalExpression,LogicalExpression>	getExprMap()
IndexDescriptor	getIndexDesc()
SchemaPath	getNewPath(SchemaPath path) getNewPath: for an original path, return new rename '$N' path, notice there could be multiple renamed paths if the there are multiple functional indexes refer original path.
SchemaPath	getNewPathFromExpr(LogicalExpression expr) return a plain field path if the incoming index expression 'expr' is replaced to be a plain field
Map<LogicalExpression,Set<SchemaPath>>	getPathsInFunctionExpr()
boolean	hasFunctional()
boolean	supportEqualCharConvertToLike() Whether this implementation( may be different per storage) support rewrite rewriting varchar equality expression, e.g.

Method Detail

hasFunctional

boolean hasFunctional()

Returns:

if this index has functional indexed field, return true

getIndexDesc

IndexDescriptor getIndexDesc()

Returns:

the IndexDescriptor this IndexInfo built from

getNewPath

SchemaPath getNewPath(SchemaPath path)

getNewPath: for an original path, return new rename '$N' path, notice there could be multiple renamed paths if the there are multiple functional indexes refer original path.

Parameters:

path -

Returns:

getNewPathFromExpr

SchemaPath getNewPathFromExpr(LogicalExpression expr)

return a plain field path if the incoming index expression 'expr' is replaced to be a plain field

Parameters:

expr - suppose to be an indexed expression

Returns:

the renamed schemapath in index table for the indexed expression

getPathsInFunctionExpr

Map<LogicalExpression,Set<SchemaPath>> getPathsInFunctionExpr()

Returns:

the map of indexed expression --> the involved schema paths in a indexed expression

getExprMap

Map<LogicalExpression,LogicalExpression> getExprMap()

Returns:

the map between indexed expression and to-be-converted target expression for scan in index e.g. cast(a.b as int) -> '$0'

allNewSchemaPaths

Set<SchemaPath> allNewSchemaPaths()

Returns:

the set of all new field names for indexed functions in index

allPathsInFunction

Set<SchemaPath> allPathsInFunction()

Returns:

the set of all schemaPath exist in functional index fields

supportEqualCharConvertToLike

boolean supportEqualCharConvertToLike()

Whether this implementation( may be different per storage) support rewrite rewriting varchar equality expression, e.g. cast(a.b as varchar(2)) = 'ca' to LIKE expression: cast(a.b as varchar(2) LIKE 'ca%'