FSTIndexHandler (Pinot local segment implementations 0.12.1 API)

java.lang.Object
- org.apache.pinot.segment.local.segment.index.loader.BaseIndexHandler
- - org.apache.pinot.segment.local.segment.index.loader.invertedindex.FSTIndexHandler

All Implemented Interfaces:

IndexHandler
```
public class FSTIndexHandler
extends BaseIndexHandler
```
Helper class for fst indexes used by SegmentPreProcessor. to create FST index for column during segment load time. Currently FST index is always created (if enabled on a column) during segment generation (1) A new segment with FST index is created/refreshed. Server loads the segment. The handler detects the existence of FST index and returns. (2) A reload is issued on an existing segment with existing FST index. The handler detects the existence of FST index and returns. (3) A reload is issued on an existing segment after FST index is enabled on an existing column. Reads the dictionary to create FST index. (4) A reload is issued on an existing segment after FST index is enabled on a newly added column. In this case, the default column handler would have taken care of adding dictionary for the new column. Read the dictionary to create FST index.

Field Summary
- Fields inherited from class org.apache.pinot.segment.local.segment.index.loader.BaseIndexHandler
  _indexLoadingConfig, _segmentMetadata, _tmpForwardIndexColumns

Constructor Summary

Constructors
Constructor Description

FSTIndexHandler(SegmentMetadata segmentMetadata, IndexLoadingConfig indexLoadingConfig)

Method Summary

Modifier and Type	Method	Description
`boolean`	`needUpdateIndices(SegmentDirectory.Reader segmentReader)`	Check if there is a need to add new indices or removes obsolete indices.
`void`	`postUpdateIndicesCleanup(SegmentDirectory.Writer segmentWriter)`	Performs any cleanup actions required after the indexes have been updated.
`void`	`updateIndices(SegmentDirectory.Writer segmentWriter, IndexCreatorProvider indexCreatorProvider)`	Adds new indices and removes obsolete indices.

Methods inherited from class org.apache.pinot.segment.local.segment.index.loader.BaseIndexHandler
createForwardIndexIfNeeded

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - FSTIndexHandler
```
public FSTIndexHandler(SegmentMetadata segmentMetadata,
                       IndexLoadingConfig indexLoadingConfig)
```
- Method Detail
  - needUpdateIndices
```
public boolean needUpdateIndices(SegmentDirectory.Reader segmentReader)
```
    Description copied from interface: IndexHandler
    
    Check if there is a need to add new indices or removes obsolete indices.
    
    Returns:
    
    true if there is a need to update.
  - updateIndices
```
public void updateIndices(SegmentDirectory.Writer segmentWriter,
                          IndexCreatorProvider indexCreatorProvider)
                   throws Exception
```
    Description copied from interface: IndexHandler
    
    Adds new indices and removes obsolete indices.
    
    Throws:
    
    Exception
  - postUpdateIndicesCleanup
```
public void postUpdateIndicesCleanup(SegmentDirectory.Writer segmentWriter)
                              throws Exception
```
    Description copied from interface: IndexHandler
    
    Performs any cleanup actions required after the indexes have been updated. Should be called only after all IndexHandlers have run.
    
    Specified by:
    
    postUpdateIndicesCleanup in interface IndexHandler
    
    Overrides:
    
    postUpdateIndicesCleanup in class BaseIndexHandler
    
    Throws:
    
    Exception