Change in the default fast field tokenizer manager.

`{ fast: true }` now results in the use of a the default fast field tokenizer. (instead of no tokenizer)
The default tokenizer lowercases.

Fast field gets a different default tokenizer manager than the normal tokenizer.

The serialization of the fast field options is unchanged.

examples/aggregation.rs

@@ -37,7 +37,7 @@ fn main() -> tantivy::Result<()> {
                 .set_index_option(IndexRecordOption::WithFreqs)
                 .set_tokenizer("raw"),
         )
-        .set_fast(None)
+        .set_fast("default")
         .set_stored();
     schema_builder.add_text_field("category", text_fieldtype);
     schema_builder.add_f64_field("stock", FAST);

src/aggregation/bucket/term_agg.rs

@@ -1293,13 +1293,13 @@ mod tests {
         // searching for terma, but min_doc_count will return all terms
         let res = exec_request_with_query(agg_req, &index, Some(("string2", "hit")))?;
 
-        assert_eq!(res["my_texts"]["buckets"][0]["key"], "A");
+        assert_eq!(res["my_texts"]["buckets"][0]["key"], "a");
         assert_eq!(res["my_texts"]["buckets"][0]["doc_count"], 2);
         assert_eq!(
             res["my_texts"]["buckets"][0]["elhistogram"]["buckets"],
             json!([{ "doc_count": 1, "key": 1.0 }, { "doc_count": 1, "key": 2.0 } ])
         );
-        assert_eq!(res["my_texts"]["buckets"][1]["key"], "B");
+        assert_eq!(res["my_texts"]["buckets"][1]["key"], "b");
         assert_eq!(res["my_texts"]["buckets"][1]["doc_count"], 1);
         assert_eq!(
             res["my_texts"]["buckets"][1]["elhistogram"]["buckets"],
@@ -1421,10 +1421,10 @@ mod tests {
         let res = exec_request_with_query(agg_req, &index, None).unwrap();
         println!("{}", serde_json::to_string_pretty(&res).unwrap());
 
-        assert_eq!(res["my_texts"]["buckets"][0]["key"], "Hallo Hallo");
+        assert_eq!(res["my_texts"]["buckets"][0]["key"], "hallo hallo");
         assert_eq!(res["my_texts"]["buckets"][0]["doc_count"], 1);
 
-        assert_eq!(res["my_texts"]["buckets"][1]["key"], "Hello Hello");
+        assert_eq!(res["my_texts"]["buckets"][1]["key"], "hello hello");
         assert_eq!(res["my_texts"]["buckets"][1]["doc_count"], 1);
 
         Ok(())

src/aggregation/mod.rs

@@ -411,7 +411,7 @@ mod tests {
                     .set_index_option(IndexRecordOption::Basic)
                     .set_fieldnorms(false),
             )
-            .set_fast(None)
+            .set_fast("default")
             .set_stored();
         let text_field = schema_builder.add_text_field("text", text_fieldtype.clone());
         let text_field_id = schema_builder.add_text_field("text_id", text_fieldtype);
@@ -466,7 +466,7 @@ mod tests {
             .set_indexing_options(
                 TextFieldIndexing::default().set_index_option(IndexRecordOption::WithFreqs),
             )
-            .set_fast(None)
+            .set_fast("default")
             .set_stored();
         let text_field = schema_builder.add_text_field("text", text_fieldtype);
         let date_field = schema_builder.add_date_field("date", FAST);

src/core/index.rs

@@ -120,8 +120,8 @@ impl IndexBuilder {
         Self {
             schema: None,
             index_settings: IndexSettings::default(),
-            tokenizer_manager: TokenizerManager::default(),
-            fast_field_tokenizer_manager: TokenizerManager::default(),
+            tokenizer_manager: TokenizerManager::default_for_indexing(),
+            fast_field_tokenizer_manager: TokenizerManager::default_for_fast_fields(),
         }
     }
 
@@ -400,8 +400,8 @@ impl Index {
             settings: metas.index_settings.clone(),
             directory,
             schema,
-            tokenizers: TokenizerManager::default(),
-            fast_field_tokenizers: TokenizerManager::default(),
+            tokenizers: TokenizerManager::default_for_indexing(),
+            fast_field_tokenizers: TokenizerManager::default_for_fast_fields(),
             executor: Arc::new(Executor::single_thread()),
             inventory,
         }

src/fastfield/mod.rs

@@ -446,7 +446,8 @@ mod tests {
     #[test]
     fn test_text_fastfield() {
         let mut schema_builder = Schema::builder();
-        let text_field = schema_builder.add_text_field("text", TEXT | FAST);
+        let text_options: TextOptions = TextOptions::from(TEXT).set_fast("raw");
+        let text_field = schema_builder.add_text_field("text", text_options);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
 
@@ -1082,7 +1083,7 @@ mod tests {
     #[test]
     fn test_fast_field_in_json_field_expand_dots_disabled() {
         let mut schema_builder = Schema::builder();
-        let json_option = JsonObjectOptions::default().set_fast(None);
+        let json_option = JsonObjectOptions::default().set_fast("default");
         let json = schema_builder.add_json_field("json", json_option);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
@@ -1108,7 +1109,7 @@ mod tests {
     #[test]
     fn test_fast_field_in_json_field_with_tokenizer() {
         let mut schema_builder = Schema::builder();
-        let json_option = JsonObjectOptions::default().set_fast(Some("default"));
+        let json_option = JsonObjectOptions::default().set_fast("default");
         let json = schema_builder.add_json_field("json", json_option);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
@@ -1134,7 +1135,7 @@ mod tests {
     fn test_fast_field_in_json_field_expand_dots_enabled() {
         let mut schema_builder = Schema::builder();
         let json_option = JsonObjectOptions::default()
-            .set_fast(None)
+            .set_fast("default")
             .set_expand_dots_enabled();
         let json = schema_builder.add_json_field("json", json_option);
         let schema = schema_builder.build();
@@ -1202,10 +1203,10 @@ mod tests {
     #[test]
     fn test_fast_field_tokenizer() {
         let mut schema_builder = Schema::builder();
-        let opt = TextOptions::default().set_fast(Some("custom_lowercase"));
+        let opt = TextOptions::default().set_fast("custom_lowercase");
         let text_field = schema_builder.add_text_field("text", opt);
         let schema = schema_builder.build();
-        let ff_tokenizer_manager = TokenizerManager::default();
+        let ff_tokenizer_manager = TokenizerManager::default_for_fast_fields();
         ff_tokenizer_manager.register(
             "custom_lowercase",
             TextAnalyzer::builder(RawTokenizer::default())
@@ -1238,7 +1239,7 @@ mod tests {
                     .set_index_option(crate::schema::IndexRecordOption::WithFreqs)
                     .set_tokenizer("raw"),
             )
-            .set_fast(Some("default"))
+            .set_fast("default")
             .set_stored();
 
         let log_field = schema_builder.add_text_field("log_level", text_fieldtype);
@@ -1271,7 +1272,7 @@ mod tests {
     fn test_shadowing_fast_field_with_expand_dots() {
         let mut schema_builder = Schema::builder();
         let json_option = JsonObjectOptions::default()
-            .set_fast(None)
+            .set_fast("default")
             .set_expand_dots_enabled();
         let json_field = schema_builder.add_json_field("jsonfield", json_option.clone());
         let shadowing_json_field = schema_builder.add_json_field("jsonfield.attr", json_option);

src/fastfield/readers.rs

@@ -349,7 +349,7 @@ mod tests {
         schema_builder.add_json_field(
             "json_expand_dots_enabled",
             JsonObjectOptions::default()
-                .set_fast(None)
+                .set_fast("default")
                 .set_expand_dots_enabled(),
         );
         let dynamic_field = schema_builder.add_json_field("_dyna", FAST);

src/fastfield/writer.rs

@@ -18,6 +18,8 @@ const JSON_DEPTH_LIMIT: usize = 20;
 pub struct FastFieldsWriter {
     columnar_writer: ColumnarWriter,
     fast_field_names: Vec<Option<String>>, //< TODO see if we can hash the field name hash too.
+    // Field -> Fast field tokenizer mapping.
+    // All text fast fields should have a tokenizer.
     per_field_tokenizer: Vec<Option<TextAnalyzer>>,
     date_precisions: Vec<DateTimePrecision>,
     expand_dots: Vec<bool>,
@@ -61,7 +63,7 @@ impl FastFieldsWriter {
                 if let Some(tokenizer_name) = json_object_options.get_fast_field_tokenizer_name() {
                     let text_analyzer = tokenizer_manager.get(tokenizer_name).ok_or_else(|| {
                         TantivyError::InvalidArgument(format!(
-                            "Tokenizer {tokenizer_name:?} not found"
+                            "Tokenizer `{tokenizer_name}` not found"
                         ))
                     })?;
                     per_field_tokenizer[field_id.field_id() as usize] = Some(text_analyzer);
@@ -157,9 +159,6 @@ impl FastFieldsWriter {
                                     &token.text,
                                 );
                             })
-                        } else {
-                            self.columnar_writer
-                                .record_str(doc_id, field_name.as_str(), text_val);
                         }
                     }
                     Value::Bytes(bytes_val) => {
@@ -201,18 +200,20 @@ impl FastFieldsWriter {
                         self.json_path_buffer.clear();
                         self.json_path_buffer.push_str(field_name);
 
-                        let text_analyzer =
+                        let text_analyzer_opt =
                             &mut self.per_field_tokenizer[field_value.field().field_id() as usize];
 
-                        record_json_obj_to_columnar_writer(
-                            doc_id,
-                            json_obj,
-                            expand_dots,
-                            JSON_DEPTH_LIMIT,
-                            &mut self.json_path_buffer,
-                            &mut self.columnar_writer,
-                            text_analyzer,
-                        );
+                        if let Some(text_analyzer) = text_analyzer_opt {
+                            record_json_obj_to_columnar_writer(
+                                doc_id,
+                                json_obj,
+                                expand_dots,
+                                JSON_DEPTH_LIMIT,
+                                &mut self.json_path_buffer,
+                                &mut self.columnar_writer,
+                                text_analyzer,
+                            );
+                        }
                     }
                     Value::IpAddr(ip_addr) => {
                         self.columnar_writer
@@ -263,7 +264,7 @@ fn record_json_obj_to_columnar_writer(
     remaining_depth_limit: usize,
     json_path_buffer: &mut String,
     columnar_writer: &mut columnar::ColumnarWriter,
-    tokenizer: &mut Option<TextAnalyzer>,
+    text_analyzer: &mut TextAnalyzer,
 ) {
     for (key, child) in json_obj {
         let len_path = json_path_buffer.len();
@@ -288,7 +289,7 @@ fn record_json_obj_to_columnar_writer(
             remaining_depth_limit,
             json_path_buffer,
             columnar_writer,
-            tokenizer,
+            text_analyzer,
         );
         // popping our sub path.
         json_path_buffer.truncate(len_path);
@@ -302,7 +303,7 @@ fn record_json_value_to_columnar_writer(
     mut remaining_depth_limit: usize,
     json_path_writer: &mut String,
     columnar_writer: &mut columnar::ColumnarWriter,
-    tokenizer: &mut Option<TextAnalyzer>,
+    text_analyzer: &mut TextAnalyzer,
 ) {
     if remaining_depth_limit == 0 {
         return;
@@ -321,14 +322,10 @@ fn record_json_value_to_columnar_writer(
             }
         }
         serde_json::Value::String(text) => {
-            if let Some(text_analyzer) = tokenizer.as_mut() {
-                let mut token_stream = text_analyzer.token_stream(text);
-                token_stream.process(&mut |token| {
-                    columnar_writer.record_str(doc, json_path_writer.as_str(), &token.text);
-                })
-            } else {
-                columnar_writer.record_str(doc, json_path_writer.as_str(), text);
-            }
+            let mut token_stream = text_analyzer.token_stream(text);
+            token_stream.process(&mut |token| {
+                columnar_writer.record_str(doc, json_path_writer.as_str(), &token.text);
+            });
         }
         serde_json::Value::Array(arr) => {
             for el in arr {
@@ -339,7 +336,7 @@ fn record_json_value_to_columnar_writer(
                     remaining_depth_limit,
                     json_path_writer,
                     columnar_writer,
-                    tokenizer,
+                    text_analyzer,
                 );
             }
         }
@@ -351,7 +348,7 @@ fn record_json_value_to_columnar_writer(
                 remaining_depth_limit,
                 json_path_writer,
                 columnar_writer,
-                tokenizer,
+                text_analyzer,
             );
         }
     }
@@ -371,6 +368,9 @@ mod tests {
     ) -> ColumnarReader {
         let mut columnar_writer = ColumnarWriter::default();
         let mut json_path = String::new();
+        let mut text_analyzer = crate::tokenizer::TokenizerManager::default_for_fast_fields()
+            .get(crate::schema::DEFAULT_FAST_FIELD_TOKENIZER)
+            .unwrap();
         for (doc, json_doc) in json_docs.iter().enumerate() {
             record_json_value_to_columnar_writer(
                 doc as u32,
@@ -379,7 +379,7 @@ mod tests {
                 JSON_DEPTH_LIMIT,
                 &mut json_path,
                 &mut columnar_writer,
-                &mut None,
+                &mut text_analyzer,
             );
         }
         let mut buffer = Vec::new();
@@ -399,6 +399,7 @@ mod tests {
         });
         let columnar_reader = test_columnar_from_jsons_aux(&[json_doc], false);
         let columns = columnar_reader.list_columns().unwrap();
+        assert_eq!(columns.len(), 5);
         {
             assert_eq!(columns[0].0, "arr");
             let column_arr_opt: Option<StrColumn> = columns[0].1.open().unwrap().into();
@@ -434,7 +435,9 @@ mod tests {
         {
             assert_eq!(columns[4].0, "text");
             let column_text_opt: Option<StrColumn> = columns[4].1.open().unwrap().into();
-            assert!(column_text_opt.unwrap().term_ords(0).eq([0].into_iter()));
+            let column_text = column_text_opt.unwrap();
+            let term_ords: Vec<u64> = column_text.term_ords(0).collect();
+            assert_eq!(&term_ords[..], &[0]);
         }
     }
 

src/query/query_parser/query_parser.rs

@@ -956,7 +956,7 @@ mod test {
             .iter()
             .flat_map(|field_name| schema.get_field(field_name))
             .collect();
-        let tokenizer_manager = TokenizerManager::default();
+        let tokenizer_manager = TokenizerManager::default_for_indexing();
         tokenizer_manager.register(
             "en_with_stop_words",
             TextAnalyzer::builder(SimpleTokenizer::default())
@@ -1447,7 +1447,7 @@ mod test {
         let title = schema_builder.add_text_field("title", text_options);
         let schema = schema_builder.build();
         let default_fields = vec![title];
-        let tokenizer_manager = TokenizerManager::default();
+        let tokenizer_manager = TokenizerManager::default_for_indexing();
         let query_parser = QueryParser::new(schema, default_fields, tokenizer_manager);
 
         assert_matches!(
@@ -1622,7 +1622,8 @@ mod test {
         let mut schema_builder = Schema::builder();
         schema_builder.add_text_field(r#"a\.b"#, STRING);
         let schema = schema_builder.build();
-        let query_parser = QueryParser::new(schema, Vec::new(), TokenizerManager::default());
+        let query_parser =
+            QueryParser::new(schema, Vec::new(), TokenizerManager::default_for_indexing());
         let query = query_parser.parse_query(r#"a\.b:hello"#).unwrap();
         assert_eq!(
             format!("{query:?}"),
@@ -1639,8 +1640,11 @@ mod test {
         schema_builder.add_text_field("first.toto.titi", STRING);
         schema_builder.add_text_field("third.a.b.c", STRING);
         let schema = schema_builder.build();
-        let query_parser =
-            QueryParser::new(schema.clone(), Vec::new(), TokenizerManager::default());
+        let query_parser = QueryParser::new(
+            schema.clone(),
+            Vec::new(),
+            TokenizerManager::default_for_indexing(),
+        );
         assert_eq!(
             query_parser.split_full_path("first.toto"),
             Some((schema.get_field("first.toto").unwrap(), ""))

src/schema/json_object_options.rs

@@ -4,7 +4,7 @@ use serde::{Deserialize, Serialize};
 
 use super::text_options::{FastFieldTextOptions, TokenizerName};
 use crate::schema::flags::{FastFlag, SchemaFlagList, StoredFlag};
-use crate::schema::{TextFieldIndexing, TextOptions};
+use crate::schema::{TextFieldIndexing, TextOptions, DEFAULT_FAST_FIELD_TOKENIZER};
 
 /// The `JsonObjectOptions` make it possible to
 /// configure how a json object field should be indexed and stored.
@@ -58,20 +58,19 @@ impl JsonObjectOptions {
     /// Returns true if and only if the json object fields are
     /// to be treated as fast fields.
     pub fn is_fast(&self) -> bool {
-        matches!(self.fast, FastFieldTextOptions::IsEnabled(true))
-            || matches!(
-                &self.fast,
-                FastFieldTextOptions::EnabledWithTokenizer { with_tokenizer: _ }
-            )
+        match self.fast {
+            FastFieldTextOptions::Disabled => false,
+            FastFieldTextOptions::Enabled { .. } => true,
+        }
     }
 
     /// Returns true if and only if the value is a fast field.
     pub fn get_fast_field_tokenizer_name(&self) -> Option<&str> {
         match &self.fast {
-            FastFieldTextOptions::IsEnabled(true) | FastFieldTextOptions::IsEnabled(false) => None,
-            FastFieldTextOptions::EnabledWithTokenizer {
-                with_tokenizer: tokenizer,
-            } => Some(tokenizer.name()),
+            FastFieldTextOptions::Disabled => None,
+            FastFieldTextOptions::Enabled {
+                tokenizer: with_tokenizer,
+            } => Some(with_tokenizer.name()),
         }
     }
 
@@ -130,15 +129,11 @@ impl JsonObjectOptions {
     /// [`TermDictionary::ord_to_term()`](crate::termdict::TermDictionary::ord_to_term)
     /// from the dictionary.
     #[must_use]
-    pub fn set_fast(mut self, tokenizer_name: Option<&str>) -> Self {
-        if let Some(tokenizer) = tokenizer_name {
-            let tokenizer = TokenizerName::from_name(tokenizer);
-            self.fast = FastFieldTextOptions::EnabledWithTokenizer {
-                with_tokenizer: tokenizer,
-            }
-        } else {
-            self.fast = FastFieldTextOptions::IsEnabled(true);
-        }
+    pub fn set_fast(mut self, tokenizer_name: &str) -> Self {
+        let with_tokenizer = TokenizerName::from_name(tokenizer_name);
+        self.fast = FastFieldTextOptions::Enabled {
+            tokenizer: with_tokenizer,
+        };
         self
     }
 
@@ -166,7 +161,9 @@ impl From<FastFlag> for JsonObjectOptions {
         JsonObjectOptions {
             stored: false,
             indexing: None,
-            fast: FastFieldTextOptions::IsEnabled(true),
+            fast: FastFieldTextOptions::Enabled {
+                tokenizer: TokenizerName::from_static(DEFAULT_FAST_FIELD_TOKENIZER),
+            },
             expand_dots_enabled: false,
         }
     }

src/schema/mod.rs

@@ -1,7 +1,7 @@
 //! Schema definition for tantivy's indices.
-//!
 //! # Setting your schema in Tantivy
 //!
+//!
 //! Tantivy has a very strict schema.
 //! The schema defines information about the fields your index contains, that is, for each field:
 //!
@@ -153,6 +153,8 @@ pub use self::term::{Term, ValueBytes, JSON_END_OF_PATH};
 pub use self::text_options::{TextFieldIndexing, TextOptions, STRING, TEXT};
 pub use self::value::Value;
 
+pub(crate) const DEFAULT_FAST_FIELD_TOKENIZER: &str = "default";
+
 /// Validator for a potential `field_name`.
 /// Returns true if the name can be use for a field name.
 ///

src/schema/text_options.rs

@@ -24,19 +24,68 @@ pub struct TextOptions {
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
-#[serde(untagged)]
+#[serde(
+    into = "FastFieldTextOptionsForSerialization",
+    from = "FastFieldTextOptionsForSerialization"
+)]
 /// Enum to control how the fast field setting of a text field.
+#[derive(Default)]
 pub(crate) enum FastFieldTextOptions {
-    /// Flag to enable/disable
-    IsEnabled(bool),
+    /// Fastfield disabled
+    #[default]
+    Disabled,
     /// Enable with tokenizer. The tokenizer must be available on the fast field tokenizer manager.
     /// `Index::fast_field_tokenizer`.
-    EnabledWithTokenizer { with_tokenizer: TokenizerName },
+    Enabled { tokenizer: TokenizerName },
 }
 
-impl Default for FastFieldTextOptions {
-    fn default() -> Self {
-        FastFieldTextOptions::IsEnabled(false)
+/// Enum used to control the way we serialize fast field text options.
+///
+/// For backward compatiblity reasons, we folow the format introduce in tantivy 0.19.
+/// `false` -> Disabled
+/// `true` -> Enabled with default tokenizer
+/// `{ tokenizer: "something" }` -> Enabled with a specific tokenizer.
+#[derive(Serialize, Deserialize)]
+#[serde(untagged)]
+enum FastFieldTextOptionsForSerialization {
+    IsEnabled(bool),
+    EnabledWithTokenizer {
+        #[serde(alias = "with_tokenizer")]
+        tokenizer: TokenizerName,
+    },
+}
+
+impl From<FastFieldTextOptionsForSerialization> for FastFieldTextOptions {
+    fn from(value: FastFieldTextOptionsForSerialization) -> Self {
+        match value {
+            FastFieldTextOptionsForSerialization::IsEnabled(enabled) => {
+                if enabled {
+                    FastFieldTextOptions::Enabled {
+                        tokenizer: TokenizerName::from_static(
+                            crate::schema::DEFAULT_FAST_FIELD_TOKENIZER,
+                        ),
+                    }
+                } else {
+                    FastFieldTextOptions::Disabled
+                }
+            }
+            FastFieldTextOptionsForSerialization::EnabledWithTokenizer { tokenizer } => {
+                FastFieldTextOptions::Enabled { tokenizer }
+            }
+        }
+    }
+}
+
+impl From<FastFieldTextOptions> for FastFieldTextOptionsForSerialization {
+    fn from(value: FastFieldTextOptions) -> Self {
+        match value {
+            FastFieldTextOptions::Disabled => {
+                FastFieldTextOptionsForSerialization::IsEnabled(false)
+            }
+            FastFieldTextOptions::Enabled { tokenizer } => {
+                FastFieldTextOptionsForSerialization::EnabledWithTokenizer { tokenizer }
+            }
+        }
     }
 }
 
@@ -45,23 +94,13 @@ impl BitOr<FastFieldTextOptions> for FastFieldTextOptions {
 
     fn bitor(self, other: FastFieldTextOptions) -> FastFieldTextOptions {
         match (self, other) {
-            (
-                FastFieldTextOptions::EnabledWithTokenizer {
-                    with_tokenizer: tokenizer,
-                },
-                _,
-            )
-            | (
-                _,
-                FastFieldTextOptions::EnabledWithTokenizer {
-                    with_tokenizer: tokenizer,
-                },
-            ) => FastFieldTextOptions::EnabledWithTokenizer {
-                with_tokenizer: tokenizer,
-            },
-            (FastFieldTextOptions::IsEnabled(true), _)
-            | (_, FastFieldTextOptions::IsEnabled(true)) => FastFieldTextOptions::IsEnabled(true),
-            (_, FastFieldTextOptions::IsEnabled(false)) => FastFieldTextOptions::IsEnabled(false),
+            (FastFieldTextOptions::Enabled { tokenizer }, _)
+            | (_, FastFieldTextOptions::Enabled { tokenizer }) => {
+                FastFieldTextOptions::Enabled { tokenizer }
+            }
+            (FastFieldTextOptions::Disabled, FastFieldTextOptions::Disabled) => {
+                FastFieldTextOptions::Disabled
+            }
         }
     }
 }
@@ -83,20 +122,17 @@ impl TextOptions {
 
     /// Returns true if and only if the value is a fast field.
     pub fn is_fast(&self) -> bool {
-        matches!(self.fast, FastFieldTextOptions::IsEnabled(true))
-            || matches!(
-                &self.fast,
-                FastFieldTextOptions::EnabledWithTokenizer { with_tokenizer: _ }
-            )
+        match &self.fast {
+            FastFieldTextOptions::Disabled => false,
+            FastFieldTextOptions::Enabled { .. } => true,
+        }
     }
 
     /// Returns true if and only if the value is a fast field.
     pub fn get_fast_field_tokenizer_name(&self) -> Option<&str> {
         match &self.fast {
-            FastFieldTextOptions::IsEnabled(true) | FastFieldTextOptions::IsEnabled(false) => None,
-            FastFieldTextOptions::EnabledWithTokenizer {
-                with_tokenizer: tokenizer,
-            } => Some(tokenizer.name()),
+            FastFieldTextOptions::Disabled => None,
+            FastFieldTextOptions::Enabled { tokenizer } => Some(tokenizer.name()),
         }
     }
 
@@ -121,15 +157,9 @@ impl TextOptions {
     /// [`TermDictionary::ord_to_term()`](crate::termdict::TermDictionary::ord_to_term)
     /// from the dictionary.
     #[must_use]
-    pub fn set_fast(mut self, tokenizer_name: Option<&str>) -> TextOptions {
-        if let Some(tokenizer) = tokenizer_name {
-            let tokenizer = TokenizerName::from_name(tokenizer);
-            self.fast = FastFieldTextOptions::EnabledWithTokenizer {
-                with_tokenizer: tokenizer,
-            }
-        } else {
-            self.fast = FastFieldTextOptions::IsEnabled(true);
-        }
+    pub fn set_fast(mut self, tokenizer_name: &str) -> TextOptions {
+        let tokenizer = TokenizerName::from_name(tokenizer_name);
+        self.fast = FastFieldTextOptions::Enabled { tokenizer };
         self
     }
 
@@ -263,7 +293,7 @@ pub const STRING: TextOptions = TextOptions {
         record: IndexRecordOption::Basic,
     }),
     stored: false,
-    fast: FastFieldTextOptions::IsEnabled(false),
+    fast: FastFieldTextOptions::Disabled,
     coerce: false,
 };
 
@@ -276,7 +306,7 @@ pub const TEXT: TextOptions = TextOptions {
     }),
     stored: false,
     coerce: false,
-    fast: FastFieldTextOptions::IsEnabled(false),
+    fast: FastFieldTextOptions::Disabled,
 };
 
 impl<T: Into<TextOptions>> BitOr<T> for TextOptions {
@@ -326,7 +356,9 @@ impl From<FastFlag> for TextOptions {
         TextOptions {
             indexing: None,
             stored: false,
-            fast: FastFieldTextOptions::IsEnabled(true),
+            fast: FastFieldTextOptions::Enabled {
+                tokenizer: TokenizerName::from_static(crate::schema::DEFAULT_FAST_FIELD_TOKENIZER),
+            },
             coerce: false,
         }
     }
@@ -392,21 +424,21 @@ mod tests {
     #[test]
     fn serde_fast_field_tokenizer() {
         let json = r#" {
-            "fast": { "with_tokenizer": "default" }
+            "fast": { "tokenizer": "default" }
         } "#;
         let options: TextOptions = serde_json::from_str(json).unwrap();
         assert_eq!(
             options.fast,
-            FastFieldTextOptions::EnabledWithTokenizer {
-                with_tokenizer: TokenizerName::from_static("default")
+            FastFieldTextOptions::Enabled {
+                tokenizer: TokenizerName::from_static("default")
             }
         );
         let options: TextOptions =
             serde_json::from_str(&serde_json::to_string(&options).unwrap()).unwrap();
         assert_eq!(
             options.fast,
-            FastFieldTextOptions::EnabledWithTokenizer {
-                with_tokenizer: TokenizerName::from_static("default")
+            FastFieldTextOptions::Enabled {
+                tokenizer: TokenizerName::from_static("default")
             }
         );
 
@@ -414,18 +446,28 @@ mod tests {
             "fast": true
         } "#;
         let options: TextOptions = serde_json::from_str(json).unwrap();
-        assert_eq!(options.fast, FastFieldTextOptions::IsEnabled(true));
+        assert_eq!(
+            options.fast,
+            FastFieldTextOptions::Enabled {
+                tokenizer: TokenizerName::from_static(DEFAULT_FAST_FIELD_TOKENIZER)
+            }
+        );
         let options: TextOptions =
             serde_json::from_str(&serde_json::to_string(&options).unwrap()).unwrap();
-        assert_eq!(options.fast, FastFieldTextOptions::IsEnabled(true));
+        assert_eq!(
+            options.fast,
+            FastFieldTextOptions::Enabled {
+                tokenizer: TokenizerName::from_static(DEFAULT_FAST_FIELD_TOKENIZER)
+            }
+        );
 
         let json = r#" {
             "fast": false
         } "#;
         let options: TextOptions = serde_json::from_str(json).unwrap();
-        assert_eq!(options.fast, FastFieldTextOptions::IsEnabled(false));
+        assert_eq!(options.fast, FastFieldTextOptions::Disabled);
         let options: TextOptions =
             serde_json::from_str(&serde_json::to_string(&options).unwrap()).unwrap();
-        assert_eq!(options.fast, FastFieldTextOptions::IsEnabled(false));
+        assert_eq!(options.fast, FastFieldTextOptions::Disabled);
     }
 }

src/tokenizer/mod.rs

@@ -189,7 +189,7 @@ pub mod tests {
 
     #[test]
     fn test_raw_tokenizer2() {
-        let tokenizer_manager = TokenizerManager::default();
+        let tokenizer_manager = TokenizerManager::default_for_indexing();
         let mut en_tokenizer = tokenizer_manager.get("raw").unwrap();
         let mut tokens: Vec<Token> = vec![];
         {
@@ -206,7 +206,7 @@ pub mod tests {
 
     #[test]
     fn test_en_tokenizer() {
-        let tokenizer_manager = TokenizerManager::default();
+        let tokenizer_manager = TokenizerManager::default_for_indexing();
         assert!(tokenizer_manager.get("en_doesnotexist").is_none());
         let mut en_tokenizer = tokenizer_manager.get("en_stem").unwrap();
         let mut tokens: Vec<Token> = vec![];
@@ -228,7 +228,7 @@ pub mod tests {
 
     #[test]
     fn test_non_en_tokenizer() {
-        let tokenizer_manager = TokenizerManager::default();
+        let tokenizer_manager = TokenizerManager::default_for_indexing();
         tokenizer_manager.register(
             "el_stem",
             TextAnalyzer::builder(SimpleTokenizer::default())
@@ -256,7 +256,7 @@ pub mod tests {
 
     #[test]
     fn test_tokenizer_empty() {
-        let tokenizer_manager = TokenizerManager::default();
+        let tokenizer_manager = TokenizerManager::default_for_indexing();
         let mut en_tokenizer = tokenizer_manager.get("en_stem").unwrap();
         {
             let mut tokens: Vec<Token> = vec![];
@@ -282,7 +282,7 @@ pub mod tests {
 
     #[test]
     fn test_whitespace_tokenizer() {
-        let tokenizer_manager = TokenizerManager::default();
+        let tokenizer_manager = TokenizerManager::default_for_indexing();
         let mut ws_tokenizer = tokenizer_manager.get("whitespace").unwrap();
         let mut tokens: Vec<Token> = vec![];
         {

src/tokenizer/tokenizer_manager.rs

@@ -27,6 +27,7 @@ pub struct TokenizerManager {
 
 impl TokenizerManager {
     /// Creates an empty tokenizer manager.
+    #[allow(clippy::new_without_default)]
     pub fn new() -> Self {
         Self {
             tokenizers: Arc::new(RwLock::new(HashMap::new())),
@@ -51,12 +52,10 @@ impl TokenizerManager {
             .get(tokenizer_name)
             .cloned()
     }
-}
 
-impl Default for TokenizerManager {
     /// Creates an `TokenizerManager` prepopulated with
     /// the default pre-configured tokenizers of `tantivy`.
-    fn default() -> TokenizerManager {
+    pub fn default_for_indexing() -> TokenizerManager {
         let manager = TokenizerManager::new();
         manager.register("raw", RawTokenizer::default());
         manager.register(
@@ -77,4 +76,28 @@ impl Default for TokenizerManager {
         manager.register("whitespace", WhitespaceTokenizer::default());
         manager
     }
+
+    /// Creates an `TokenizerManager` prepopulated with
+    /// the default pre-configured tokenizers of `tantivy`
+    /// for fast fields.
+    ///
+    /// Fast fields usually do not really tokenize the text.
+    /// It is however very useful to filter / normalize the text.
+    pub fn default_for_fast_fields() -> TokenizerManager {
+        let manager = TokenizerManager::new();
+        let raw_tokenizer = TextAnalyzer::builder(RawTokenizer::default())
+            .filter(RemoveLongFilter::limit(255))
+            .build();
+        let lower_tokenizer = TextAnalyzer::builder(RawTokenizer::default())
+            .filter(RemoveLongFilter::limit(255))
+            .filter(LowerCaser)
+            .build();
+        manager.register(
+            crate::schema::DEFAULT_FAST_FIELD_TOKENIZER,
+            lower_tokenizer.clone(),
+        );
+        manager.register("raw", raw_tokenizer);
+        manager.register("lower", lower_tokenizer);
+        manager
+    }
 }