---
name: "Plucene::Index::Writer"
section: "3pm"
platform: "linux"
package: "libplucene-perl"
version: "1.25-5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Plucene::Index::Writer"
---

# Plucene::Index::Writer(3pm)

write an index.

## NAME

Plucene::Index::Writer - write an index.

## SYNOPSIS

```
        my $writer = Plucene::Index::Writer->new($path, $analyser, $create);
        $writer->add_document($doc);
        $writer->add_indexes(@dirs);
        $writer->optimize; # called before close

        my $doc_count = $writer->doc_count;
        my $mergefactor = $writer->mergefactor;
        $writer->set_mergefactor($value);
```

## DESCRIPTION

This is the writer class.

If an index will not have more documents added for a while and optimal search performance is desired, then the `"optimize"` method should be called before the index is closed.

## METHODS

### new

```
        my $writer = Plucene::Index::Writer->new($path, $analyser, $create);
```

This will create a new Plucene::Index::Writer object.

The third argument to the constructor determines whether a new index is created, or whether an existing index is opened for the addition of new documents.

### mergefactor / set\_mergefactor

```
        my $mergefactor = $writer->mergefactor;
        $writer->set_mergefactor($value);
```

Get / set the mergefactor. It defaults to 5.

### doc\_count

```
        my $doc_count = $writer->doc_count;
```

### add\_document

```
        $writer->add_document($doc);
```

Adds a document to the index. After the document has been added, a merge takes place if there are more than `$Plucene::Index::Writer::mergefactor` segments in the index. This defaults to 10, but can be set to whatever value is optimal  for your application.

### optimize

```
        $writer->optimize;
```

Merges all segments together into a single segment, optimizing an index for search. This should be the last method called on an indexer, as it  invalidates the writer object.

### add\_indexes

```
        $writer->add_indexes(@dirs);
```

Merges all segments from an array of indexes into this index.

This may be used to parallelize batch indexing.  A large document collection can be broken into sub-collections.  Each sub-collection can be indexed in parallel, on a different thread, process or machine.  The complete index can then be created by merging sub-collection indexes with this method.

After this completes, the index is optimized.