writer-jill commented on code in PR #13329:
URL: https://github.com/apache/druid/pull/13329#discussion_r1018012761
##########
docs/ingestion/ingestion-spec.md:
##########
@@ -477,35 +477,37 @@ The `indexSpec` object can include the following
properties:
|-----|-----------|-------|
|bitmap|Compression format for bitmap indexes. Should be a JSON object with
`type` set to `roaring` or `concise`. For type `roaring`, the boolean property
`compressRunOnSerialization` (defaults to true) controls whether or not
run-length encoding will be used when it is determined to be more
space-efficient.|`{"type": "roaring"}`|
|dimensionCompression|Compression format for dimension columns. Options are
`lz4`, `lzf`, `zstd`, or `uncompressed`.|`lz4`|
-|stringDictionaryEncoding|Encoding format for string typed column value
dictionaries.|`{"type":"utf8"}`|
+|stringDictionaryEncoding|Encoding format for STRING-typed column value
dictionaries. The default setting `utf8` suits most use cases.<br>Example to
enable front coding: `{"type":"frontCoded", "bucketSize": 4}`<br>`bucketSize`
is the number of values to place in a bucket to perform delta encoding. Must be
a power of 2, maximum is 128. Defaults to 4.<br>See [Front
coding](#front-coding) for more information.|`{"type":"utf8"}`|
|metricCompression|Compression format for primitive type metric columns.
Options are `lz4`, `lzf`, `zstd`, `uncompressed`, or `none` (which is more
efficient than `uncompressed`, but not supported by older versions of
Druid).|`lz4`|
|longEncoding|Encoding format for long-typed columns. Applies regardless of
whether they are dimensions or metrics. Options are `auto` or `longs`. `auto`
encodes the values using offset or lookup table depending on column
cardinality, and store them with variable size. `longs` stores the value as-is
with 8 bytes each.|`longs`|
|jsonCompression|Compression format to use for nested column raw data. Options
are `lz4`, `lzf`, `zstd`, or `uncompressed`.|`lz4`|
+##### Front coding
-#### String Dictionary Encoding
+By default, Druid stores values in STRING-typed columns as uncompressed UTF-8
encoded bytes.
-##### UTF8
-By default, `STRING` typed column store the values as uncompressed UTF8
encoded bytes.
+Starting in version 25.0, Druid can store STRING columns using an incremental
encoding strategy called front coding. This allows Druid to create smaller
UTF-8 encoded segments with very little performance cost.
Review Comment:
Added COMPLEX<json> to this section.
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