extra commit

* Make add_field() to public

* cargo format

CHANGELOG.md

@@ -1,3 +1,17 @@
+Tantivy 0.11.3
+=======================
+- Fixed DateTime as a fast field (#735)
+
+Tantivy 0.11.2
+=======================
+- The future returned by `IndexWriter::merge` does not borrow `self` mutably anymore (#732)
+- Exposing a constructor for `WatchHandle` (#731)
+
+Tantivy 0.11.1
+=====================
+- Bug fix #729
+
+
 Tantivy 0.11.0
 =====================
 

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "tantivy"
-version = "0.11.0"
+version = "0.11.3"
 authors = ["Paul Masurel <paul.masurel@gmail.com>"]
 license = "MIT"
 categories = ["database-implementations", "data-structures"]

examples/faceted_search.rs

@@ -13,63 +13,100 @@
 // ---
 // Importing tantivy...
 use tantivy::collector::FacetCollector;
-use tantivy::query::AllQuery;
+use tantivy::query::{AllQuery, TermQuery};
 use tantivy::schema::*;
 use tantivy::{doc, Index};
-use tempfile::TempDir;
 
 fn main() -> tantivy::Result<()> {
-    // Let's create a temporary directory for the
-    // sake of this example
-    let index_path = TempDir::new()?;
+    // Let's create a temporary directory for the sake of this example
     let mut schema_builder = Schema::builder();
 
-    schema_builder.add_text_field("name", TEXT | STORED);
-
-    // this is our faceted field
-    schema_builder.add_facet_field("tags");
+    let name = schema_builder.add_text_field("felin_name", TEXT | STORED);
+    // this is our faceted field: its scientific classification
+    let classification = schema_builder.add_facet_field("classification");
 
     let schema = schema_builder.build();
+    let index = Index::create_in_ram(schema);
 
-    let index = Index::create_in_dir(&index_path, schema.clone())?;
-
-    let mut index_writer = index.writer(50_000_000)?;
-
-    let name = schema.get_field("name").unwrap();
-    let tags = schema.get_field("tags").unwrap();
+    let mut index_writer = index.writer(30_000_000)?;
 
     // For convenience, tantivy also comes with a macro to
     // reduce the boilerplate above.
     index_writer.add_document(doc!(
-        name => "the ditch",
-        tags => Facet::from("/pools/north")
+        name => "Cat",
+        classification => Facet::from("/Felidae/Felinae/Felis")
     ));
-
     index_writer.add_document(doc!(
-        name => "little stacey",
-        tags => Facet::from("/pools/south")
+        name => "Canada lynx",
+        classification => Facet::from("/Felidae/Felinae/Lynx")
+    ));
+    index_writer.add_document(doc!(
+        name => "Cheetah",
+        classification => Facet::from("/Felidae/Felinae/Acinonyx")
+    ));
+    index_writer.add_document(doc!(
+        name => "Tiger",
+        classification => Facet::from("/Felidae/Pantherinae/Panthera")
+    ));
+    index_writer.add_document(doc!(
+        name => "Lion",
+        classification => Facet::from("/Felidae/Pantherinae/Panthera")
+    ));
+    index_writer.add_document(doc!(
+        name => "Jaguar",
+        classification => Facet::from("/Felidae/Pantherinae/Panthera")
+    ));
+    index_writer.add_document(doc!(
+        name => "Sunda clouded leopard",
+        classification => Facet::from("/Felidae/Pantherinae/Neofelis")
+    ));
+    index_writer.add_document(doc!(
+        name => "Fossa",
+        classification => Facet::from("/Eupleridae/Cryptoprocta")
     ));
-
     index_writer.commit()?;
 
     let reader = index.reader()?;
-
     let searcher = reader.searcher();
+    {
+        let mut facet_collector = FacetCollector::for_field(classification);
+        facet_collector.add_facet("/Felidae");
+        let facet_counts = searcher.search(&AllQuery, &facet_collector)?;
+        // This lists all of the facet counts, right below "/Felidae".
+        let facets: Vec<(&Facet, u64)> = facet_counts.get("/Felidae").collect();
+        assert_eq!(
+            facets,
+            vec![
+                (&Facet::from("/Felidae/Felinae"), 3),
+                (&Facet::from("/Felidae/Pantherinae"), 4),
+            ]
+        );
+    }
 
-    let mut facet_collector = FacetCollector::for_field(tags);
-    facet_collector.add_facet("/pools");
+    // Facets are also searchable.
+    //
+    // For instance a common UI pattern is to allow the user someone to click on a facet link
+    // (e.g: `Pantherinae`) to drill down and filter the current result set with this subfacet.
+    //
+    // The search would then look as follows.
 
-    let facet_counts = searcher.search(&AllQuery, &facet_collector).unwrap();
-
-    // This lists all of the facet counts
-    let facets: Vec<(&Facet, u64)> = facet_counts.get("/pools").collect();
-    assert_eq!(
-        facets,
-        vec![
-            (&Facet::from("/pools/north"), 1),
-            (&Facet::from("/pools/south"), 1),
-        ]
-    );
+    // Check the reference doc for different ways to create a `Facet` object.
+    {
+        let facet = Facet::from_text("/Felidae/Pantherinae");
+        let facet_term = Term::from_facet(classification, &facet);
+        let facet_term_query = TermQuery::new(facet_term, IndexRecordOption::Basic);
+        let mut facet_collector = FacetCollector::for_field(classification);
+        facet_collector.add_facet("/Felidae/Pantherinae");
+        let facet_counts = searcher.search(&facet_term_query, &facet_collector)?;
+        let facets: Vec<(&Facet, u64)> = facet_counts.get("/Felidae/Pantherinae").collect();
+        assert_eq!(
+            facets,
+            vec![
+                (&Facet::from("/Felidae/Pantherinae/Neofelis"), 1),
+                (&Facet::from("/Felidae/Pantherinae/Panthera"), 3),
+            ]
+        );
+    }
 
     Ok(())
 }

src/collector/facet_collector.rs

@@ -452,9 +452,11 @@ impl FacetCounts {
 #[cfg(test)]
 mod tests {
     use super::{FacetCollector, FacetCounts};
+    use crate::collector::Count;
     use crate::core::Index;
-    use crate::query::AllQuery;
-    use crate::schema::{Document, Facet, Field, Schema};
+    use crate::query::{AllQuery, QueryParser, TermQuery};
+    use crate::schema::{Document, Facet, Field, IndexRecordOption, Schema};
+    use crate::Term;
     use rand::distributions::Uniform;
     use rand::prelude::SliceRandom;
     use rand::{thread_rng, Rng};
@@ -544,6 +546,56 @@ mod tests {
         assert_eq!(facets[0].1, 1);
     }
 
+    #[test]
+    fn test_doc_search_by_facet() {
+        let mut schema_builder = Schema::builder();
+        let facet_field = schema_builder.add_facet_field("facet");
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema);
+        let mut index_writer = index.writer_with_num_threads(1, 3_000_000).unwrap();
+        index_writer.add_document(doc!(
+            facet_field => Facet::from_text(&"/A/A"),
+        ));
+        index_writer.add_document(doc!(
+            facet_field => Facet::from_text(&"/A/B"),
+        ));
+        index_writer.add_document(doc!(
+            facet_field => Facet::from_text(&"/A/C/A"),
+        ));
+        index_writer.add_document(doc!(
+            facet_field => Facet::from_text(&"/D/C/A"),
+        ));
+        index_writer.commit().unwrap();
+        let reader = index.reader().unwrap();
+        let searcher = reader.searcher();
+        assert_eq!(searcher.num_docs(), 4);
+
+        let count_facet = |facet_str: &str| {
+            let term = Term::from_facet(facet_field, &Facet::from_text(facet_str));
+            searcher
+                .search(&TermQuery::new(term, IndexRecordOption::Basic), &Count)
+                .unwrap()
+        };
+
+        assert_eq!(count_facet("/"), 4);
+        assert_eq!(count_facet("/A"), 3);
+        assert_eq!(count_facet("/A/B"), 1);
+        assert_eq!(count_facet("/A/C"), 1);
+        assert_eq!(count_facet("/A/C/A"), 1);
+        assert_eq!(count_facet("/C/A"), 0);
+        {
+            let query_parser = QueryParser::for_index(&index, vec![]);
+            {
+                let query = query_parser.parse_query("facet:/A/B").unwrap();
+                assert_eq!(1, searcher.search(&query, &Count).unwrap());
+            }
+            {
+                let query = query_parser.parse_query("facet:/A").unwrap();
+                assert_eq!(3, searcher.search(&query, &Count).unwrap());
+            }
+        }
+    }
+
     #[test]
     fn test_non_used_facet_collector() {
         let mut facet_collector = FacetCollector::for_field(Field::from_field_id(0));

src/common/composite_file.rs

@@ -186,7 +186,7 @@ mod test {
     use super::{CompositeFile, CompositeWrite};
     use crate::common::BinarySerializable;
     use crate::common::VInt;
-    use crate::directory::{Directory, RAMDirectory};
+    use crate::directory::{Directory, RAMDirectory, ReadOnlyDirectory};
     use crate::schema::Field;
     use std::io::Write;
     use std::path::Path;

src/core/index.rs

@@ -338,7 +338,7 @@ impl Index {
 
     /// Creates a new segment.
     pub fn new_segment(&self) -> Segment {
-        let segment_meta = self
+        let mut segment_meta = self
             .inventory
             .new_segment_meta(SegmentId::generate_random(), 0);
         self.segment(segment_meta)

src/core/index_meta.rs

@@ -35,6 +35,7 @@ impl SegmentMetaInventory {
             segment_id,
             max_doc,
             deletes: None,
+            bundled: false,
         };
         SegmentMeta::from(self.inventory.track(inner))
     }
@@ -81,6 +82,19 @@ impl SegmentMeta {
         self.tracked.segment_id
     }
 
+    pub fn with_bundled(self) -> SegmentMeta {
+        SegmentMeta::from(self.tracked.map(|inner| InnerSegmentMeta {
+            segment_id: inner.segment_id,
+            max_doc: inner.max_doc,
+            deletes: inner.deletes.clone(),
+            bundled: true,
+        }))
+    }
+
+    pub fn is_bundled(&self) -> bool {
+        self.tracked.bundled
+    }
+
     /// Returns the number of deleted documents.
     pub fn num_deleted_docs(&self) -> u32 {
         self.tracked
@@ -107,8 +121,12 @@ impl SegmentMeta {
     /// It just joins the segment id with the extension
     /// associated to a segment component.
     pub fn relative_path(&self, component: SegmentComponent) -> PathBuf {
-        let mut path = self.id().uuid_string();
-        path.push_str(&*match component {
+        let suffix = self.suffix(component);
+        self.relative_path_from_suffix(&suffix)
+    }
+
+    fn suffix(&self, component: SegmentComponent) -> String {
+        match component {
             SegmentComponent::POSTINGS => ".idx".to_string(),
             SegmentComponent::POSITIONS => ".pos".to_string(),
             SegmentComponent::POSITIONSSKIP => ".posidx".to_string(),
@@ -117,7 +135,17 @@ impl SegmentMeta {
             SegmentComponent::FASTFIELDS => ".fast".to_string(),
             SegmentComponent::FIELDNORMS => ".fieldnorm".to_string(),
             SegmentComponent::DELETE => format!(".{}.del", self.delete_opstamp().unwrap_or(0)),
-        });
+        }
+    }
+
+    /// Returns the relative path of a component of our segment.
+    ///
+    /// It just joins the segment id with the extension
+    /// associated to a segment component.
+    pub fn relative_path_from_suffix(&self, suffix: &str) -> PathBuf {
+        let mut path = self.id().uuid_string();
+        path.push_str(".");
+        path.push_str(&suffix);
         PathBuf::from(path)
     }
 
@@ -161,6 +189,7 @@ impl SegmentMeta {
             segment_id: inner_meta.segment_id,
             max_doc,
             deletes: None,
+            bundled: inner_meta.bundled,
         });
         SegmentMeta { tracked }
     }
@@ -175,6 +204,7 @@ impl SegmentMeta {
             segment_id: inner_meta.segment_id,
             max_doc: inner_meta.max_doc,
             deletes: Some(delete_meta),
+            bundled: inner_meta.bundled,
         });
         SegmentMeta { tracked }
     }
@@ -185,6 +215,7 @@ struct InnerSegmentMeta {
     segment_id: SegmentId,
     max_doc: u32,
     deletes: Option<DeleteMeta>,
+    bundled: bool,
 }
 
 impl InnerSegmentMeta {

src/core/segment.rs

@@ -4,14 +4,12 @@ use crate::core::SegmentId;
 use crate::core::SegmentMeta;
 use crate::directory::error::{OpenReadError, OpenWriteError};
 use crate::directory::Directory;
-use crate::directory::{ReadOnlySource, WritePtr};
+use crate::directory::{ReadOnlyDirectory, ReadOnlySource, WritePtr};
 use crate::indexer::segment_serializer::SegmentSerializer;
 use crate::schema::Schema;
 use crate::Opstamp;
-use crate::Result;
 use std::fmt;
 use std::path::PathBuf;
-use std::result;
 
 /// A segment is a piece of the index.
 #[derive(Clone)]
@@ -83,23 +81,30 @@ impl Segment {
     }
 
     /// Open one of the component file for a *regular* read.
-    pub fn open_read(
-        &self,
-        component: SegmentComponent,
-    ) -> result::Result<ReadOnlySource, OpenReadError> {
+    pub fn open_read(&self, component: SegmentComponent) -> Result<ReadOnlySource, OpenReadError> {
         let path = self.relative_path(component);
         let source = self.index.directory().open_read(&path)?;
         Ok(source)
     }
 
     /// Open one of the component file for *regular* write.
-    pub fn open_write(
+    pub fn open_write(&mut self, component: SegmentComponent) -> Result<WritePtr, OpenWriteError> {
+        let path = self.relative_path(component);
+        self.index.directory_mut().open_write(&path)
+    }
+
+    pub fn open_bundle_writer(&mut self) -> Result<WritePtr, OpenWriteError> {
+        let path = self.meta.relative_path_from_suffix("bundle");
+        self.index.directory_mut().open_write(&path)
+    }
+
+    pub(crate) fn open_write_in_directory(
         &mut self,
         component: SegmentComponent,
-    ) -> result::Result<WritePtr, OpenWriteError> {
+        directory: &mut dyn Directory,
+    ) -> Result<WritePtr, OpenWriteError> {
         let path = self.relative_path(component);
-        let write = self.index.directory_mut().open_write(&path)?;
-        Ok(write)
+        directory.open_write(&path)
     }
 }
 
@@ -109,5 +114,5 @@ pub trait SerializableSegment {
     ///
     /// # Returns
     /// The number of documents in the segment.
-    fn write(&self, serializer: SegmentSerializer) -> Result<u32>;
+    fn write(&self, serializer: SegmentSerializer) -> crate::Result<u32>;
 }

src/directory/bundle_directory.rs

@@ -0,0 +1,97 @@
+use crate::directory::directory::ReadOnlyDirectory;
+use crate::directory::error::OpenReadError;
+use crate::directory::ReadOnlySource;
+use crate::error::DataCorruption;
+use std::collections::HashMap;
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+
+#[derive(Clone)]
+struct BundleDirectory {
+    source_map: Arc<HashMap<PathBuf, ReadOnlySource>>,
+}
+
+impl BundleDirectory {
+    pub fn from_source(source: ReadOnlySource) -> Result<BundleDirectory, DataCorruption> {
+        let mut index_offset_buf = [0u8; 8];
+        let (body_idx, footer_offset) = source.split_from_end(8);
+        index_offset_buf.copy_from_slice(footer_offset.as_slice());
+        let offset = u64::from_le_bytes(index_offset_buf);
+        let (body_source, idx_source) = body_idx.split(offset as usize);
+        let idx: HashMap<PathBuf, (u64, u64)> = serde_json::from_slice(idx_source.as_slice())
+            .map_err(|err| {
+                let msg = format!("Failed to read index from bundle. {:?}", err);
+                DataCorruption::comment_only(msg)
+            })?;
+        let source_map: HashMap<PathBuf, ReadOnlySource> = idx
+            .into_iter()
+            .map(|(path, (start, stop))| {
+                let source = body_source.slice(start as usize, stop as usize);
+                (path, source)
+            })
+            .collect();
+        Ok(BundleDirectory {
+            source_map: Arc::new(source_map),
+        })
+    }
+}
+
+impl ReadOnlyDirectory for BundleDirectory {
+    fn open_read(&self, path: &Path) -> Result<ReadOnlySource, OpenReadError> {
+        self.source_map
+            .get(path)
+            .cloned()
+            .ok_or_else(|| OpenReadError::FileDoesNotExist(path.to_path_buf()))
+    }
+
+    fn exists(&self, path: &Path) -> bool {
+        self.source_map.contains_key(path)
+    }
+
+    fn atomic_read(&self, path: &Path) -> Result<Vec<u8>, OpenReadError> {
+        let source = self
+            .source_map
+            .get(path)
+            .ok_or_else(|| OpenReadError::FileDoesNotExist(path.to_path_buf()))?;
+        Ok(source.as_slice().to_vec())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::BundleDirectory;
+    use crate::directory::{RAMDirectory, ReadOnlyDirectory, TerminatingWrite};
+    use crate::Directory;
+    use std::io::Write;
+    use std::path::Path;
+
+    #[test]
+    fn test_bundle_directory() {
+        let mut ram_directory = RAMDirectory::default();
+        let test_path_atomic = Path::new("testpath_atomic");
+        let test_path_wrt = Path::new("testpath_wrt");
+        assert!(ram_directory
+            .atomic_write(test_path_atomic, b"titi")
+            .is_ok());
+        {
+            let mut test_wrt = ram_directory.open_write(test_path_wrt).unwrap();
+            assert!(test_wrt.write_all(b"toto").is_ok());
+            assert!(test_wrt.terminate().is_ok());
+        }
+        let mut dest_directory = RAMDirectory::default();
+        let bundle_path = Path::new("bundle");
+        let mut wrt = dest_directory.open_write(bundle_path).unwrap();
+        assert!(ram_directory.serialize_bundle(&mut wrt).is_ok());
+        assert!(wrt.terminate().is_ok());
+        let source = dest_directory.open_read(bundle_path).unwrap();
+        let bundle_directory = BundleDirectory::from_source(source).unwrap();
+        assert_eq!(
+            &bundle_directory.atomic_read(test_path_atomic).unwrap()[..],
+            b"titi"
+        );
+        assert_eq!(
+            &bundle_directory.open_read(test_path_wrt).unwrap()[..],
+            b"toto"
+        );
+    }
+}

src/directory/directory.rs

@@ -100,6 +100,30 @@ fn retry_policy(is_blocking: bool) -> RetryPolicy {
     }
 }
 
+pub trait ReadOnlyDirectory {
+    /// Opens a virtual file for read.
+    ///
+    /// Once a virtual file is open, its data may not
+    /// change.
+    ///
+    /// Specifically, subsequent writes or flushes should
+    /// have no effect on the returned `ReadOnlySource` object.
+    ///
+    /// You should only use this to read files create with [Directory::open_write].
+    fn open_read(&self, path: &Path) -> result::Result<ReadOnlySource, OpenReadError>;
+
+    /// Returns true iff the file exists
+    fn exists(&self, path: &Path) -> bool;
+
+    /// Reads the full content file that has been written using
+    /// atomic_write.
+    ///
+    /// This should only be used for small files.
+    ///
+    /// You should only use this to read files create with [Directory::atomic_write].
+    fn atomic_read(&self, path: &Path) -> Result<Vec<u8>, OpenReadError>;
+}
+
 /// Write-once read many (WORM) abstraction for where
 /// tantivy's data should be stored.
 ///
@@ -110,18 +134,9 @@ fn retry_policy(is_blocking: bool) -> RetryPolicy {
 /// - The [`RAMDirectory`](struct.RAMDirectory.html), which
 /// should be used mostly for tests.
 ///
-pub trait Directory: DirectoryClone + fmt::Debug + Send + Sync + 'static {
-    /// Opens a virtual file for read.
-    ///
-    /// Once a virtual file is open, its data may not
-    /// change.
-    ///
-    /// Specifically, subsequent writes or flushes should
-    /// have no effect on the returned `ReadOnlySource` object.
-    ///
-    /// You should only use this to read files create with [`open_write`]
-    fn open_read(&self, path: &Path) -> result::Result<ReadOnlySource, OpenReadError>;
-
+pub trait Directory:
+    DirectoryClone + ReadOnlyDirectory + fmt::Debug + Send + Sync + 'static
+{
     /// Removes a file
     ///
     /// Removing a file will not affect an eventual
@@ -131,9 +146,6 @@ pub trait Directory: DirectoryClone + fmt::Debug + Send + Sync + 'static {
     /// `DeleteError::DoesNotExist`.
     fn delete(&self, path: &Path) -> result::Result<(), DeleteError>;
 
-    /// Returns true iff the file exists
-    fn exists(&self, path: &Path) -> bool;
-
     /// Opens a writer for the *virtual file* associated with
     /// a Path.
     ///
@@ -155,14 +167,6 @@ pub trait Directory: DirectoryClone + fmt::Debug + Send + Sync + 'static {
     /// The file may not previously exist.
     fn open_write(&mut self, path: &Path) -> Result<WritePtr, OpenWriteError>;
 
-    /// Reads the full content file that has been written using
-    /// atomic_write.
-    ///
-    /// This should only be used for small files.
-    ///
-    /// You should only use this to read files create with [`atomic_write`]
-    fn atomic_read(&self, path: &Path) -> Result<Vec<u8>, OpenReadError>;
-
     /// Atomically replace the content of a file with data.
     ///
     /// This calls ensure that reads can never *observe*
@@ -197,7 +201,7 @@ pub trait Directory: DirectoryClone + fmt::Debug + Send + Sync + 'static {
     /// Registers a callback that will be called whenever a change on the `meta.json`
     /// using the `atomic_write` API is detected.
     ///
-    /// The behavior when using `.watch()` on a file using `.open_write(...)` is, on the other
+    /// The behavior when using `.watch()` on a file using [Directory::open_write] is, on the other
     /// hand, undefined.
     ///
     /// The file will be watched for the lifetime of the returned `WatchHandle`. The caller is

src/directory/managed_directory.rs

@@ -10,6 +10,7 @@ use crate::directory::{WatchCallback, WatchHandle};
 use crate::error::DataCorruption;
 use crate::Directory;
 
+use crate::directory::directory::ReadOnlyDirectory;
 use crc32fast::Hasher;
 use serde_json;
 use std::collections::HashSet;
@@ -264,14 +265,6 @@ impl ManagedDirectory {
 }
 
 impl Directory for ManagedDirectory {
-    fn open_read(&self, path: &Path) -> result::Result<ReadOnlySource, OpenReadError> {
-        let read_only_source = self.directory.open_read(path)?;
-        let (footer, reader) = Footer::extract_footer(read_only_source)
-            .map_err(|err| IOError::with_path(path.to_path_buf(), err))?;
-        footer.is_compatible()?;
-        Ok(reader)
-    }
-
     fn open_write(&mut self, path: &Path) -> result::Result<WritePtr, OpenWriteError> {
         self.register_file_as_managed(path)
             .map_err(|e| IOError::with_path(path.to_owned(), e))?;
@@ -289,18 +282,10 @@ impl Directory for ManagedDirectory {
         self.directory.atomic_write(path, data)
     }
 
-    fn atomic_read(&self, path: &Path) -> result::Result<Vec<u8>, OpenReadError> {
-        self.directory.atomic_read(path)
-    }
-
     fn delete(&self, path: &Path) -> result::Result<(), DeleteError> {
         self.directory.delete(path)
     }
 
-    fn exists(&self, path: &Path) -> bool {
-        self.directory.exists(path)
-    }
-
     fn acquire_lock(&self, lock: &Lock) -> result::Result<DirectoryLock, LockError> {
         self.directory.acquire_lock(lock)
     }
@@ -310,6 +295,24 @@ impl Directory for ManagedDirectory {
     }
 }
 
+impl ReadOnlyDirectory for ManagedDirectory {
+    fn open_read(&self, path: &Path) -> result::Result<ReadOnlySource, OpenReadError> {
+        let read_only_source = self.directory.open_read(path)?;
+        let (footer, reader) = Footer::extract_footer(read_only_source)
+            .map_err(|err| IOError::with_path(path.to_path_buf(), err))?;
+        footer.is_compatible()?;
+        Ok(reader)
+    }
+
+    fn exists(&self, path: &Path) -> bool {
+        self.directory.exists(path)
+    }
+
+    fn atomic_read(&self, path: &Path) -> result::Result<Vec<u8>, OpenReadError> {
+        self.directory.atomic_read(path)
+    }
+}
+
 impl Clone for ManagedDirectory {
     fn clone(&self) -> ManagedDirectory {
         ManagedDirectory {
@@ -323,7 +326,9 @@ impl Clone for ManagedDirectory {
 #[cfg(test)]
 mod tests_mmap_specific {
 
-    use crate::directory::{Directory, ManagedDirectory, MmapDirectory, TerminatingWrite};
+    use crate::directory::{
+        Directory, ManagedDirectory, MmapDirectory, ReadOnlyDirectory, TerminatingWrite,
+    };
     use std::collections::HashSet;
     use std::fs::OpenOptions;
     use std::io::Write;

src/directory/mmap_directory.rs

@@ -6,6 +6,7 @@ use self::notify::RawEvent;
 use self::notify::RecursiveMode;
 use self::notify::Watcher;
 use crate::core::META_FILEPATH;
+use crate::directory::directory::ReadOnlyDirectory;
 use crate::directory::error::LockError;
 use crate::directory::error::{
     DeleteError, IOError, OpenDirectoryError, OpenReadError, OpenWriteError,
@@ -131,14 +132,13 @@ impl MmapCache {
         }
         self.cache.remove(full_path);
         self.counters.miss += 1;
-        Ok(if let Some(mmap) = open_mmap(full_path)? {
+        let mmap_opt = open_mmap(full_path)?;
+        Ok(mmap_opt.map(|mmap| {
             let mmap_arc: Arc<BoxedData> = Arc::new(Box::new(mmap));
             let mmap_weak = Arc::downgrade(&mmap_arc);
             self.cache.insert(full_path.to_owned(), mmap_weak);
-            Some(mmap_arc)
-        } else {
-            None
-        })
+            mmap_arc
+        }))
     }
 }
 
@@ -408,24 +408,6 @@ impl TerminatingWrite for SafeFileWriter {
 }
 
 impl Directory for MmapDirectory {
-    fn open_read(&self, path: &Path) -> result::Result<ReadOnlySource, OpenReadError> {
-        debug!("Open Read {:?}", path);
-        let full_path = self.resolve_path(path);
-
-        let mut mmap_cache = self.inner.mmap_cache.write().map_err(|_| {
-            let msg = format!(
-                "Failed to acquired write lock \
-                 on mmap cache while reading {:?}",
-                path
-            );
-            IOError::with_path(path.to_owned(), make_io_err(msg))
-        })?;
-        Ok(mmap_cache
-            .get_mmap(&full_path)?
-            .map(ReadOnlySource::from)
-            .unwrap_or_else(ReadOnlySource::empty))
-    }
-
     /// Any entry associated to the path in the mmap will be
     /// removed before the file is deleted.
     fn delete(&self, path: &Path) -> result::Result<(), DeleteError> {
@@ -444,11 +426,6 @@ impl Directory for MmapDirectory {
         }
     }
 
-    fn exists(&self, path: &Path) -> bool {
-        let full_path = self.resolve_path(path);
-        full_path.exists()
-    }
-
     fn open_write(&mut self, path: &Path) -> Result<WritePtr, OpenWriteError> {
         debug!("Open Write {:?}", path);
         let full_path = self.resolve_path(path);
@@ -479,25 +456,6 @@ impl Directory for MmapDirectory {
         Ok(BufWriter::new(Box::new(writer)))
     }
 
-    fn atomic_read(&self, path: &Path) -> Result<Vec<u8>, OpenReadError> {
-        let full_path = self.resolve_path(path);
-        let mut buffer = Vec::new();
-        match File::open(&full_path) {
-            Ok(mut file) => {
-                file.read_to_end(&mut buffer)
-                    .map_err(|e| IOError::with_path(path.to_owned(), e))?;
-                Ok(buffer)
-            }
-            Err(e) => {
-                if e.kind() == io::ErrorKind::NotFound {
-                    Err(OpenReadError::FileDoesNotExist(path.to_owned()))
-                } else {
-                    Err(IOError::with_path(path.to_owned(), e).into())
-                }
-            }
-        }
-    }
-
     fn atomic_write(&mut self, path: &Path, data: &[u8]) -> io::Result<()> {
         debug!("Atomic Write {:?}", path);
         let full_path = self.resolve_path(path);
@@ -531,6 +489,50 @@ impl Directory for MmapDirectory {
     }
 }
 
+impl ReadOnlyDirectory for MmapDirectory {
+    fn open_read(&self, path: &Path) -> result::Result<ReadOnlySource, OpenReadError> {
+        debug!("Open Read {:?}", path);
+        let full_path = self.resolve_path(path);
+
+        let mut mmap_cache = self.inner.mmap_cache.write().map_err(|_| {
+            let msg = format!(
+                "Failed to acquired write lock \
+                 on mmap cache while reading {:?}",
+                path
+            );
+            IOError::with_path(path.to_owned(), make_io_err(msg))
+        })?;
+        Ok(mmap_cache
+            .get_mmap(&full_path)?
+            .map(ReadOnlySource::from)
+            .unwrap_or_else(ReadOnlySource::empty))
+    }
+
+    fn exists(&self, path: &Path) -> bool {
+        let full_path = self.resolve_path(path);
+        full_path.exists()
+    }
+
+    fn atomic_read(&self, path: &Path) -> Result<Vec<u8>, OpenReadError> {
+        let full_path = self.resolve_path(path);
+        let mut buffer = Vec::new();
+        match File::open(&full_path) {
+            Ok(mut file) => {
+                file.read_to_end(&mut buffer)
+                    .map_err(|e| IOError::with_path(path.to_owned(), e))?;
+                Ok(buffer)
+            }
+            Err(e) => {
+                if e.kind() == io::ErrorKind::NotFound {
+                    Err(OpenReadError::FileDoesNotExist(path.to_owned()))
+                } else {
+                    Err(IOError::with_path(path.to_owned(), e).into())
+                }
+            }
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
 

src/directory/mod.rs

@@ -7,6 +7,7 @@ WORM directory abstraction.
 #[cfg(feature = "mmap")]
 mod mmap_directory;
 
+mod bundle_directory;
 mod directory;
 mod directory_lock;
 mod footer;
@@ -19,15 +20,13 @@ mod watch_event_router;
 pub mod error;
 
 pub use self::directory::DirectoryLock;
-pub use self::directory::{Directory, DirectoryClone};
+pub use self::directory::{Directory, DirectoryClone, ReadOnlyDirectory};
 pub use self::directory_lock::{Lock, INDEX_WRITER_LOCK, META_LOCK};
 pub use self::ram_directory::RAMDirectory;
 pub use self::read_only_source::ReadOnlySource;
-pub(crate) use self::watch_event_router::WatchCallbackList;
-pub use self::watch_event_router::{WatchCallback, WatchHandle};
+pub use self::watch_event_router::{WatchCallback, WatchCallbackList, WatchHandle};
 use std::io::{self, BufWriter, Write};
 use std::path::PathBuf;
-
 /// Outcome of the Garbage collection
 pub struct GarbageCollectionResult {
     /// List of files that were deleted in this cycle

src/directory/ram_directory.rs

@@ -1,4 +1,6 @@
+use crate::common::CountingWriter;
 use crate::core::META_FILEPATH;
+use crate::directory::directory::ReadOnlyDirectory;
 use crate::directory::error::{DeleteError, OpenReadError, OpenWriteError};
 use crate::directory::AntiCallToken;
 use crate::directory::WatchCallbackList;
@@ -115,6 +117,22 @@ impl InnerDirectory {
     fn total_mem_usage(&self) -> usize {
         self.fs.values().map(|f| f.len()).sum()
     }
+
+    fn serialize_bundle(&self, wrt: &mut WritePtr) -> io::Result<()> {
+        let mut counting_writer = CountingWriter::wrap(wrt);
+        let mut file_index: HashMap<PathBuf, (u64, u64)> = HashMap::default();
+        for (path, source) in &self.fs {
+            let start = counting_writer.written_bytes();
+            counting_writer.write_all(source.as_slice())?;
+            let stop = counting_writer.written_bytes();
+            file_index.insert(path.to_path_buf(), (start, stop));
+        }
+        let index_offset = counting_writer.written_bytes();
+        serde_json::to_writer(&mut counting_writer, &file_index)?;
+        let index_offset_buffer = index_offset.to_le_bytes();
+        counting_writer.write_all(&index_offset_buffer[..])?;
+        Ok(())
+    }
 }
 
 impl fmt::Debug for RAMDirectory {
@@ -144,13 +162,18 @@ impl RAMDirectory {
     pub fn total_mem_usage(&self) -> usize {
         self.fs.read().unwrap().total_mem_usage()
     }
+
+    /// Serialize the RAMDirectory into a bundle.
+    ///
+    /// This method will fail, write nothing, and return an error if a
+    /// clone of this repository exists.
+    pub fn serialize_bundle(self, wrt: &mut WritePtr) -> io::Result<()> {
+        let inner_directory_rlock = self.fs.read().unwrap();
+        inner_directory_rlock.serialize_bundle(wrt)
+    }
 }
 
 impl Directory for RAMDirectory {
-    fn open_read(&self, path: &Path) -> result::Result<ReadOnlySource, OpenReadError> {
-        self.fs.read().unwrap().open_read(path)
-    }
-
     fn delete(&self, path: &Path) -> result::Result<(), DeleteError> {
         fail_point!("RAMDirectory::delete", |_| {
             use crate::directory::error::IOError;
@@ -160,10 +183,6 @@ impl Directory for RAMDirectory {
         self.fs.write().unwrap().delete(path)
     }
 
-    fn exists(&self, path: &Path) -> bool {
-        self.fs.read().unwrap().exists(path)
-    }
-
     fn open_write(&mut self, path: &Path) -> Result<WritePtr, OpenWriteError> {
         let mut fs = self.fs.write().unwrap();
         let path_buf = PathBuf::from(path);
@@ -177,10 +196,6 @@ impl Directory for RAMDirectory {
         }
     }
 
-    fn atomic_read(&self, path: &Path) -> Result<Vec<u8>, OpenReadError> {
-        Ok(self.open_read(path)?.as_slice().to_owned())
-    }
-
     fn atomic_write(&mut self, path: &Path, data: &[u8]) -> io::Result<()> {
         fail_point!("RAMDirectory::atomic_write", |msg| Err(io::Error::new(
             io::ErrorKind::Other,
@@ -204,3 +219,17 @@ impl Directory for RAMDirectory {
         Ok(self.fs.write().unwrap().watch(watch_callback))
     }
 }
+
+impl ReadOnlyDirectory for RAMDirectory {
+    fn open_read(&self, path: &Path) -> result::Result<ReadOnlySource, OpenReadError> {
+        self.fs.read().unwrap().open_read(path)
+    }
+
+    fn exists(&self, path: &Path) -> bool {
+        self.fs.read().unwrap().exists(path)
+    }
+
+    fn atomic_read(&self, path: &Path) -> Result<Vec<u8>, OpenReadError> {
+        Ok(self.open_read(path)?.as_slice().to_owned())
+    }
+}

src/directory/watch_event_router.rs

@@ -24,13 +24,20 @@ pub struct WatchCallbackList {
 #[derive(Clone)]
 pub struct WatchHandle(Arc<WatchCallback>);
 
+impl WatchHandle {
+    /// Create a WatchHandle handle.
+    pub fn new(watch_callback: Arc<WatchCallback>) -> WatchHandle {
+        WatchHandle(watch_callback)
+    }
+}
+
 impl WatchCallbackList {
     /// Suscribes a new callback and returns a handle that controls the lifetime of the callback.
     pub fn subscribe(&self, watch_callback: WatchCallback) -> WatchHandle {
         let watch_callback_arc = Arc::new(watch_callback);
         let watch_callback_weak = Arc::downgrade(&watch_callback_arc);
         self.router.write().unwrap().push(watch_callback_weak);
-        WatchHandle(watch_callback_arc)
+        WatchHandle::new(watch_callback_arc)
     }
 
     fn list_callback(&self) -> Vec<Arc<WatchCallback>> {

src/error.rs

@@ -25,10 +25,10 @@ impl DataCorruption {
         }
     }
 
-    pub fn comment_only(comment: String) -> DataCorruption {
+    pub fn comment_only<TS: ToString>(comment: TS) -> DataCorruption {
         DataCorruption {
             filepath: None,
-            comment,
+            comment: comment.to_string(),
         }
     }
 }

src/fastfield/mod.rs

@@ -33,6 +33,7 @@ pub use self::reader::FastFieldReader;
 pub use self::readers::FastFieldReaders;
 pub use self::serializer::FastFieldSerializer;
 pub use self::writer::{FastFieldsWriter, IntFastFieldWriter};
+use crate::chrono::{NaiveDateTime, Utc};
 use crate::common;
 use crate::schema::Cardinality;
 use crate::schema::FieldType;
@@ -49,7 +50,7 @@ mod serializer;
 mod writer;
 
 /// Trait for types that are allowed for fast fields: (u64, i64 and f64).
-pub trait FastValue: Default + Clone + Copy + Send + Sync + PartialOrd {
+pub trait FastValue: Clone + Copy + Send + Sync + PartialOrd {
     /// Converts a value from u64
     ///
     /// Internally all fast field values are encoded as u64.
@@ -69,6 +70,12 @@ pub trait FastValue: Default + Clone + Copy + Send + Sync + PartialOrd {
     /// Cast value to `u64`.
     /// The value is just reinterpreted in memory.
     fn as_u64(&self) -> u64;
+
+    /// Build a default value. This default value is never used, so the value does not
+    /// really matter.
+    fn make_zero() -> Self {
+        Self::from_u64(0i64.to_u64())
+    }
 }
 
 impl FastValue for u64 {
@@ -135,11 +142,34 @@ impl FastValue for f64 {
     }
 }
 
+impl FastValue for crate::DateTime {
+    fn from_u64(timestamp_u64: u64) -> Self {
+        let timestamp_i64 = i64::from_u64(timestamp_u64);
+        crate::DateTime::from_utc(NaiveDateTime::from_timestamp(timestamp_i64, 0), Utc)
+    }
+
+    fn to_u64(&self) -> u64 {
+        self.timestamp().to_u64()
+    }
+
+    fn fast_field_cardinality(field_type: &FieldType) -> Option<Cardinality> {
+        match *field_type {
+            FieldType::Date(ref integer_options) => integer_options.get_fastfield_cardinality(),
+            _ => None,
+        }
+    }
+
+    fn as_u64(&self) -> u64 {
+        self.timestamp().as_u64()
+    }
+}
+
 fn value_to_u64(value: &Value) -> u64 {
     match *value {
         Value::U64(ref val) => *val,
         Value::I64(ref val) => common::i64_to_u64(*val),
         Value::F64(ref val) => common::f64_to_u64(*val),
+        Value::Date(ref datetime) => common::i64_to_u64(datetime.timestamp()),
         _ => panic!("Expected a u64/i64/f64 field, got {:?} ", value),
     }
 }
@@ -149,12 +179,14 @@ mod tests {
 
     use super::*;
     use crate::common::CompositeFile;
-    use crate::directory::{Directory, RAMDirectory, WritePtr};
+    use crate::directory::{Directory, RAMDirectory, ReadOnlyDirectory, WritePtr};
     use crate::fastfield::FastFieldReader;
-    use crate::schema::Document;
+    use crate::merge_policy::NoMergePolicy;
     use crate::schema::Field;
     use crate::schema::Schema;
     use crate::schema::FAST;
+    use crate::schema::{Document, IntOptions};
+    use crate::{Index, SegmentId, SegmentReader};
     use once_cell::sync::Lazy;
     use rand::prelude::SliceRandom;
     use rand::rngs::StdRng;
@@ -178,6 +210,12 @@ mod tests {
         assert_eq!(test_fastfield.get(2), 300);
     }
 
+    #[test]
+    pub fn test_fastfield_i64_u64() {
+        let datetime = crate::DateTime::from_utc(NaiveDateTime::from_timestamp(0i64, 0), Utc);
+        assert_eq!(i64::from_u64(datetime.to_u64()), 0i64);
+    }
+
     #[test]
     fn test_intfastfield_small() {
         let path = Path::new("test");
@@ -429,6 +467,93 @@ mod tests {
             }
         }
     }
+
+    #[test]
+    fn test_merge_missing_date_fast_field() {
+        let mut schema_builder = Schema::builder();
+        let date_field = schema_builder.add_date_field("date", FAST);
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema);
+        let mut index_writer = index.writer_with_num_threads(1, 3_000_000).unwrap();
+        index_writer.set_merge_policy(Box::new(NoMergePolicy));
+        index_writer.add_document(doc!(date_field =>crate::chrono::prelude::Utc::now()));
+        index_writer.commit().unwrap();
+        index_writer.add_document(doc!());
+        index_writer.commit().unwrap();
+        let reader = index.reader().unwrap();
+        let segment_ids: Vec<SegmentId> = reader
+            .searcher()
+            .segment_readers()
+            .iter()
+            .map(SegmentReader::segment_id)
+            .collect();
+        assert_eq!(segment_ids.len(), 2);
+        let merge_future = index_writer.merge(&segment_ids[..]);
+        let merge_res = futures::executor::block_on(merge_future);
+        assert!(merge_res.is_ok());
+        assert!(reader.reload().is_ok());
+        assert_eq!(reader.searcher().segment_readers().len(), 1);
+    }
+
+    #[test]
+    fn test_default_datetime() {
+        assert_eq!(crate::DateTime::make_zero().timestamp(), 0i64);
+    }
+
+    #[test]
+    fn test_datefastfield() {
+        use crate::fastfield::FastValue;
+        let mut schema_builder = Schema::builder();
+        let date_field = schema_builder.add_date_field("date", FAST);
+        let multi_date_field = schema_builder.add_date_field(
+            "multi_date",
+            IntOptions::default().set_fast(Cardinality::MultiValues),
+        );
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema);
+        let mut index_writer = index.writer_with_num_threads(1, 3_000_000).unwrap();
+        index_writer.set_merge_policy(Box::new(NoMergePolicy));
+        index_writer.add_document(doc!(
+            date_field => crate::DateTime::from_u64(1i64.to_u64()),
+            multi_date_field => crate::DateTime::from_u64(2i64.to_u64()),
+            multi_date_field => crate::DateTime::from_u64(3i64.to_u64())
+        ));
+        index_writer.add_document(doc!(
+            date_field => crate::DateTime::from_u64(4i64.to_u64())
+        ));
+        index_writer.add_document(doc!(
+            multi_date_field => crate::DateTime::from_u64(5i64.to_u64()),
+            multi_date_field => crate::DateTime::from_u64(6i64.to_u64())
+        ));
+        index_writer.commit().unwrap();
+        let reader = index.reader().unwrap();
+        let searcher = reader.searcher();
+        assert_eq!(searcher.segment_readers().len(), 1);
+        let segment_reader = searcher.segment_reader(0);
+        let fast_fields = segment_reader.fast_fields();
+        let date_fast_field = fast_fields.date(date_field).unwrap();
+        let dates_fast_field = fast_fields.dates(multi_date_field).unwrap();
+        let mut dates = vec![];
+        {
+            assert_eq!(date_fast_field.get(0u32).timestamp(), 1i64);
+            dates_fast_field.get_vals(0u32, &mut dates);
+            assert_eq!(dates.len(), 2);
+            assert_eq!(dates[0].timestamp(), 2i64);
+            assert_eq!(dates[1].timestamp(), 3i64);
+        }
+        {
+            assert_eq!(date_fast_field.get(1u32).timestamp(), 4i64);
+            dates_fast_field.get_vals(1u32, &mut dates);
+            assert!(dates.is_empty());
+        }
+        {
+            assert_eq!(date_fast_field.get(2u32).timestamp(), 0i64);
+            dates_fast_field.get_vals(2u32, &mut dates);
+            assert_eq!(dates.len(), 2);
+            assert_eq!(dates[0].timestamp(), 5i64);
+            assert_eq!(dates[1].timestamp(), 6i64);
+        }
+    }
 }
 
 #[cfg(all(test, feature = "unstable"))]

src/fastfield/multivalued/reader.rs

@@ -45,7 +45,7 @@ impl<Item: FastValue> MultiValueIntFastFieldReader<Item> {
     pub fn get_vals(&self, doc: DocId, vals: &mut Vec<Item>) {
         let (start, stop) = self.range(doc);
         let len = (stop - start) as usize;
-        vals.resize(len, Item::default());
+        vals.resize(len, Item::make_zero());
         self.vals_reader.get_range_u64(start, &mut vals[..]);
     }
 

src/fastfield/reader.rs

@@ -4,7 +4,7 @@ use crate::common::compute_num_bits;
 use crate::common::BinarySerializable;
 use crate::common::CompositeFile;
 use crate::directory::ReadOnlySource;
-use crate::directory::{Directory, RAMDirectory, WritePtr};
+use crate::directory::{Directory, RAMDirectory, ReadOnlyDirectory, WritePtr};
 use crate::fastfield::{FastFieldSerializer, FastFieldsWriter};
 use crate::schema::Schema;
 use crate::schema::FAST;

src/fastfield/readers.rs

@@ -15,9 +15,11 @@ pub struct FastFieldReaders {
     fast_field_i64: HashMap<Field, FastFieldReader<i64>>,
     fast_field_u64: HashMap<Field, FastFieldReader<u64>>,
     fast_field_f64: HashMap<Field, FastFieldReader<f64>>,
+    fast_field_date: HashMap<Field, FastFieldReader<crate::DateTime>>,
     fast_field_i64s: HashMap<Field, MultiValueIntFastFieldReader<i64>>,
     fast_field_u64s: HashMap<Field, MultiValueIntFastFieldReader<u64>>,
     fast_field_f64s: HashMap<Field, MultiValueIntFastFieldReader<f64>>,
+    fast_field_dates: HashMap<Field, MultiValueIntFastFieldReader<crate::DateTime>>,
     fast_bytes: HashMap<Field, BytesFastFieldReader>,
     fast_fields_composite: CompositeFile,
 }
@@ -26,6 +28,7 @@ enum FastType {
     I64,
     U64,
     F64,
+    Date,
 }
 
 fn type_and_cardinality(field_type: &FieldType) -> Option<(FastType, Cardinality)> {
@@ -39,6 +42,9 @@ fn type_and_cardinality(field_type: &FieldType) -> Option<(FastType, Cardinality
         FieldType::F64(options) => options
             .get_fastfield_cardinality()
             .map(|cardinality| (FastType::F64, cardinality)),
+        FieldType::Date(options) => options
+            .get_fastfield_cardinality()
+            .map(|cardinality| (FastType::Date, cardinality)),
         FieldType::HierarchicalFacet => Some((FastType::U64, Cardinality::MultiValues)),
         _ => None,
     }
@@ -53,9 +59,11 @@ impl FastFieldReaders {
             fast_field_i64: Default::default(),
             fast_field_u64: Default::default(),
             fast_field_f64: Default::default(),
+            fast_field_date: Default::default(),
             fast_field_i64s: Default::default(),
             fast_field_u64s: Default::default(),
             fast_field_f64s: Default::default(),
+            fast_field_dates: Default::default(),
             fast_bytes: Default::default(),
             fast_fields_composite: fast_fields_composite.clone(),
         };
@@ -95,6 +103,12 @@ impl FastFieldReaders {
                                         FastFieldReader::open(fast_field_data.clone()),
                                     );
                                 }
+                                FastType::Date => {
+                                    fast_field_readers.fast_field_date.insert(
+                                        field,
+                                        FastFieldReader::open(fast_field_data.clone()),
+                                    );
+                                }
                             }
                         } else {
                             return Err(From::from(FastFieldNotAvailableError::new(field_entry)));
@@ -130,6 +144,14 @@ impl FastFieldReaders {
                                         .fast_field_f64s
                                         .insert(field, multivalued_int_fast_field);
                                 }
+                                FastType::Date => {
+                                    let vals_reader = FastFieldReader::open(fast_field_data);
+                                    let multivalued_int_fast_field =
+                                        MultiValueIntFastFieldReader::open(idx_reader, vals_reader);
+                                    fast_field_readers
+                                        .fast_field_dates
+                                        .insert(field, multivalued_int_fast_field);
+                                }
                             }
                         } else {
                             return Err(From::from(FastFieldNotAvailableError::new(field_entry)));
@@ -167,6 +189,9 @@ impl FastFieldReaders {
         if let Some(f64_ff_reader) = self.f64(field) {
             return Some(f64_ff_reader.into_u64_reader());
         }
+        if let Some(date_ff_reader) = self.date(field) {
+            return Some(date_ff_reader.into_u64_reader());
+        }
         None
     }
 
@@ -177,6 +202,13 @@ impl FastFieldReaders {
         self.fast_field_i64.get(&field).cloned()
     }
 
+    /// Returns the `i64` fast field reader reader associated to `field`.
+    ///
+    /// If `field` is not a i64 fast field, this method returns `None`.
+    pub fn date(&self, field: Field) -> Option<FastFieldReader<crate::DateTime>> {
+        self.fast_field_date.get(&field).cloned()
+    }
+
     /// Returns the `f64` fast field reader reader associated to `field`.
     ///
     /// If `field` is not a f64 fast field, this method returns `None`.
@@ -223,6 +255,13 @@ impl FastFieldReaders {
         self.fast_field_f64s.get(&field).cloned()
     }
 
+    /// Returns a `crate::DateTime` multi-valued fast field reader reader associated to `field`.
+    ///
+    /// If `field` is not a `crate::DateTime` multi-valued fast field, this method returns `None`.
+    pub fn dates(&self, field: Field) -> Option<MultiValueIntFastFieldReader<crate::DateTime>> {
+        self.fast_field_dates.get(&field).cloned()
+    }
+
     /// Returns the `bytes` fast field reader associated to `field`.
     ///
     /// If `field` is not a bytes fast field, returns `None`.

src/fastfield/writer.rs

@@ -4,7 +4,7 @@ use crate::common::BinarySerializable;
 use crate::common::VInt;
 use crate::fastfield::{BytesFastFieldWriter, FastFieldSerializer};
 use crate::postings::UnorderedTermId;
-use crate::schema::{Cardinality, Document, Field, FieldType, Schema};
+use crate::schema::{Cardinality, Document, Field, FieldEntry, FieldType, Schema};
 use crate::termdict::TermOrdinal;
 use fnv::FnvHashMap;
 use std::collections::HashMap;
@@ -17,6 +17,14 @@ pub struct FastFieldsWriter {
     bytes_value_writers: Vec<BytesFastFieldWriter>,
 }
 
+fn fast_field_default_value(field_entry: &FieldEntry) -> u64 {
+    match *field_entry.field_type() {
+        FieldType::I64(_) | FieldType::Date(_) => common::i64_to_u64(0i64),
+        FieldType::F64(_) => common::f64_to_u64(0.0f64),
+        _ => 0u64,
+    }
+}
+
 impl FastFieldsWriter {
     /// Create all `FastFieldWriter` required by the schema.
     pub fn from_schema(schema: &Schema) -> FastFieldsWriter {
@@ -25,18 +33,15 @@ impl FastFieldsWriter {
         let mut bytes_value_writers = Vec::new();
 
         for (field, field_entry) in schema.fields() {
-            let default_value = match *field_entry.field_type() {
-                FieldType::I64(_) => common::i64_to_u64(0i64),
-                FieldType::F64(_) => common::f64_to_u64(0.0f64),
-                _ => 0u64,
-            };
             match *field_entry.field_type() {
                 FieldType::I64(ref int_options)
                 | FieldType::U64(ref int_options)
-                | FieldType::F64(ref int_options) => {
+                | FieldType::F64(ref int_options)
+                | FieldType::Date(ref int_options) => {
                     match int_options.get_fastfield_cardinality() {
                         Some(Cardinality::SingleValue) => {
                             let mut fast_field_writer = IntFastFieldWriter::new(field);
+                            let default_value = fast_field_default_value(field_entry);
                             fast_field_writer.set_val_if_missing(default_value);
                             single_value_writers.push(fast_field_writer);
                         }

src/indexer/index_writer.rs

@@ -142,8 +142,7 @@ pub(crate) fn advance_deletes(
         return Ok(());
     }
 
-    let mut delete_cursor = segment_entry.delete_cursor().clone();
-    if segment_entry.delete_bitset().is_none() && delete_cursor.get().is_none() {
+    if segment_entry.delete_bitset().is_none() && segment_entry.delete_cursor().get().is_none() {
         // There has been no `DeleteOperation` between the segment status and `target_opstamp`.
         return Ok(());
     }
@@ -159,7 +158,7 @@ pub(crate) fn advance_deletes(
     compute_deleted_bitset(
         &mut delete_bitset,
         &segment_reader,
-        &mut delete_cursor,
+        segment_entry.delete_cursor(),
         &DocToOpstampMapping::None,
         target_opstamp,
     )?;
@@ -515,9 +514,13 @@ impl IndexWriter {
     /// Merges a given list of segments
     ///
     /// `segment_ids` is required to be non-empty.
-    pub async fn merge(&mut self, segment_ids: &[SegmentId]) -> crate::Result<SegmentMeta> {
+    pub fn merge(
+        &mut self,
+        segment_ids: &[SegmentId],
+    ) -> impl Future<Output = crate::Result<SegmentMeta>> {
         let merge_operation = self.segment_updater.make_merge_operation(segment_ids);
-        self.segment_updater.start_merge(merge_operation)?.await
+        let segment_updater = self.segment_updater.clone();
+        async move { segment_updater.start_merge(merge_operation)?.await }
     }
 
     /// Closes the current document channel send.

src/indexer/mod.rs

@@ -33,6 +33,7 @@ pub type DefaultMergePolicy = LogMergePolicy;
 mod tests {
     use crate::schema::{self, Schema};
     use crate::{Index, Term};
+
     #[test]
     fn test_advance_delete_bug() {
         let mut schema_builder = Schema::builder();

src/indexer/segment_serializer.rs

@@ -1,10 +1,13 @@
-use crate::Result;
+use crate::Directory;
 
 use crate::core::Segment;
 use crate::core::SegmentComponent;
+use crate::directory::error::OpenWriteError;
+use crate::directory::{DirectoryClone, RAMDirectory, TerminatingWrite, WritePtr};
 use crate::fastfield::FastFieldSerializer;
 use crate::fieldnorm::FieldNormsSerializer;
 use crate::postings::InvertedIndexSerializer;
+use crate::schema::Schema;
 use crate::store::StoreWriter;
 
 /// Segment serializer is in charge of laying out on disk
@@ -14,25 +17,50 @@ pub struct SegmentSerializer {
     fast_field_serializer: FastFieldSerializer,
     fieldnorms_serializer: FieldNormsSerializer,
     postings_serializer: InvertedIndexSerializer,
+    bundle_writer: Option<(RAMDirectory, WritePtr)>,
+}
+
+pub(crate) struct SegmentSerializerWriters {
+    postings_wrt: WritePtr,
+    positions_skip_wrt: WritePtr,
+    positions_wrt: WritePtr,
+    terms_wrt: WritePtr,
+    fast_field_wrt: WritePtr,
+    fieldnorms_wrt: WritePtr,
+    store_wrt: WritePtr,
+}
+
+impl SegmentSerializerWriters {
+    pub(crate) fn for_segment(segment: &mut Segment) -> Result<Self, OpenWriteError> {
+        Ok(SegmentSerializerWriters {
+            postings_wrt: segment.open_write(SegmentComponent::POSTINGS)?,
+            positions_skip_wrt: segment.open_write(SegmentComponent::POSITIONS)?,
+            positions_wrt: segment.open_write(SegmentComponent::POSITIONSSKIP)?,
+            terms_wrt: segment.open_write(SegmentComponent::TERMS)?,
+            fast_field_wrt: segment.open_write(SegmentComponent::FASTFIELDS)?,
+            fieldnorms_wrt: segment.open_write(SegmentComponent::FIELDNORMS)?,
+            store_wrt: segment.open_write(SegmentComponent::STORE)?,
+        })
+    }
 }
 
 impl SegmentSerializer {
-    /// Creates a new `SegmentSerializer`.
-    pub fn for_segment(segment: &mut Segment) -> Result<SegmentSerializer> {
-        let store_write = segment.open_write(SegmentComponent::STORE)?;
-
-        let fast_field_write = segment.open_write(SegmentComponent::FASTFIELDS)?;
-        let fast_field_serializer = FastFieldSerializer::from_write(fast_field_write)?;
-
-        let fieldnorms_write = segment.open_write(SegmentComponent::FIELDNORMS)?;
-        let fieldnorms_serializer = FieldNormsSerializer::from_write(fieldnorms_write)?;
-
-        let postings_serializer = InvertedIndexSerializer::open(segment)?;
+    pub(crate) fn new(schema: Schema, writers: SegmentSerializerWriters) -> crate::Result<Self> {
+        let fast_field_serializer = FastFieldSerializer::from_write(writers.fast_field_wrt)?;
+        let fieldnorms_serializer = FieldNormsSerializer::from_write(writers.fieldnorms_wrt)?;
+        let postings_serializer = InvertedIndexSerializer::open(
+            schema,
+            writers.terms_wrt,
+            writers.postings_wrt,
+            writers.positions_wrt,
+            writers.positions_skip_wrt,
+        );
         Ok(SegmentSerializer {
-            store_writer: StoreWriter::new(store_write),
+            store_writer: StoreWriter::new(writers.store_wrt),
             fast_field_serializer,
             fieldnorms_serializer,
             postings_serializer,
+            bundle_writer: None,
         })
     }
 
@@ -57,11 +85,15 @@ impl SegmentSerializer {
     }
 
     /// Finalize the segment serialization.
-    pub fn close(self) -> Result<()> {
+    pub fn close(mut self) -> crate::Result<()> {
         self.fast_field_serializer.close()?;
         self.postings_serializer.close()?;
         self.store_writer.close()?;
         self.fieldnorms_serializer.close()?;
+        if let Some((ram_directory, mut bundle_wrt)) = self.bundle_writer.take() {
+            ram_directory.serialize_bundle(&mut bundle_wrt)?;
+            bundle_wrt.terminate()?;
+        }
         Ok(())
     }
 }

src/indexer/segment_updater.rs

@@ -12,6 +12,7 @@ use crate::indexer::index_writer::advance_deletes;
 use crate::indexer::merge_operation::MergeOperationInventory;
 use crate::indexer::merger::IndexMerger;
 use crate::indexer::segment_manager::SegmentsStatus;
+use crate::indexer::segment_serializer::SegmentSerializerWriters;
 use crate::indexer::stamper::Stamper;
 use crate::indexer::SegmentEntry;
 use crate::indexer::SegmentSerializer;
@@ -132,7 +133,9 @@ fn merge(
     let merger: IndexMerger = IndexMerger::open(index.schema(), &segments[..])?;
 
     // ... we just serialize this index merger in our new segment to merge the two segments.
-    let segment_serializer = SegmentSerializer::for_segment(&mut merged_segment)?;
+    let segment_serializer_wrts = SegmentSerializerWriters::for_segment(&mut merged_segment)?;
+    let segment_serializer =
+        SegmentSerializer::new(merged_segment.schema(), segment_serializer_wrts)?;
 
     let num_docs = merger.write(segment_serializer)?;
 

src/indexer/segment_writer.rs

@@ -3,7 +3,7 @@ use crate::core::Segment;
 use crate::core::SerializableSegment;
 use crate::fastfield::FastFieldsWriter;
 use crate::fieldnorm::FieldNormsWriter;
-use crate::indexer::segment_serializer::SegmentSerializer;
+use crate::indexer::segment_serializer::{SegmentSerializer, SegmentSerializerWriters};
 use crate::postings::compute_table_size;
 use crate::postings::MultiFieldPostingsWriter;
 use crate::schema::FieldType;
@@ -69,7 +69,8 @@ impl SegmentWriter {
         schema: &Schema,
     ) -> Result<SegmentWriter> {
         let table_num_bits = initial_table_size(memory_budget)?;
-        let segment_serializer = SegmentSerializer::for_segment(&mut segment)?;
+        let segment_serializer_wrts = SegmentSerializerWriters::for_segment(&mut segment)?;
+        let segment_serializer = SegmentSerializer::new(segment.schema(), segment_serializer_wrts)?;
         let multifield_postings = MultiFieldPostingsWriter::new(schema, table_num_bits);
         let tokenizers = schema
             .fields()

src/lib.rs

@@ -940,4 +940,73 @@ mod tests {
             assert_eq!(fast_field_reader.get(0), 4f64)
         }
     }
+
+    // motivated by #729
+    #[test]
+    fn test_update_via_delete_insert() {
+        use crate::collector::Count;
+        use crate::indexer::NoMergePolicy;
+        use crate::query::AllQuery;
+        use crate::SegmentId;
+        use futures::executor::block_on;
+
+        const DOC_COUNT: u64 = 2u64;
+
+        let mut schema_builder = SchemaBuilder::default();
+        let id = schema_builder.add_u64_field("id", INDEXED);
+        let schema = schema_builder.build();
+
+        let index = Index::create_in_ram(schema.clone());
+        let index_reader = index.reader().unwrap();
+
+        let mut index_writer = index.writer(3_000_000).unwrap();
+        index_writer.set_merge_policy(Box::new(NoMergePolicy));
+
+        for doc_id in 0u64..DOC_COUNT {
+            index_writer.add_document(doc!(id => doc_id));
+        }
+        index_writer.commit().unwrap();
+
+        index_reader.reload().unwrap();
+        let searcher = index_reader.searcher();
+
+        assert_eq!(
+            searcher.search(&AllQuery, &Count).unwrap(),
+            DOC_COUNT as usize
+        );
+
+        // update the 10 elements by deleting and re-adding
+        for doc_id in 0u64..DOC_COUNT {
+            index_writer.delete_term(Term::from_field_u64(id, doc_id));
+            index_writer.commit().unwrap();
+            index_reader.reload().unwrap();
+            let doc = doc!(id =>  doc_id);
+            index_writer.add_document(doc);
+            index_writer.commit().unwrap();
+            index_reader.reload().unwrap();
+            let searcher = index_reader.searcher();
+            // The number of document should be stable.
+            assert_eq!(
+                searcher.search(&AllQuery, &Count).unwrap(),
+                DOC_COUNT as usize
+            );
+        }
+
+        index_reader.reload().unwrap();
+        let searcher = index_reader.searcher();
+        let segment_ids: Vec<SegmentId> = searcher
+            .segment_readers()
+            .into_iter()
+            .map(|reader| reader.segment_id())
+            .collect();
+        block_on(index_writer.merge(&segment_ids)).unwrap();
+
+        index_reader.reload().unwrap();
+        let searcher = index_reader.searcher();
+
+        assert_eq!(
+            searcher.search(&AllQuery, &Count).unwrap(),
+            DOC_COUNT as usize
+        );
+    }
 }

src/postings/mod.rs

@@ -75,7 +75,7 @@ pub mod tests {
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
         let mut segment = index.new_segment();
-        let mut posting_serializer = InvertedIndexSerializer::open(&mut segment).unwrap();
+        let mut posting_serializer = InvertedIndexSerializer::for_segment(&mut segment).unwrap();
         {
             let mut field_serializer = posting_serializer.new_field(text_field, 120 * 4).unwrap();
             field_serializer.new_term("abc".as_bytes()).unwrap();

src/postings/serializer.rs

@@ -10,8 +10,8 @@ use crate::postings::USE_SKIP_INFO_LIMIT;
 use crate::schema::Schema;
 use crate::schema::{Field, FieldEntry, FieldType};
 use crate::termdict::{TermDictionaryBuilder, TermOrdinal};
-use crate::DocId;
 use crate::Result;
+use crate::{Directory, DocId};
 use std::io::{self, Write};
 
 /// `InvertedIndexSerializer` is in charge of serializing
@@ -54,33 +54,36 @@ pub struct InvertedIndexSerializer {
 }
 
 impl InvertedIndexSerializer {
-    /// Open a new `InvertedIndexSerializer` for the given segment
-    fn create(
-        terms_write: CompositeWrite<WritePtr>,
-        postings_write: CompositeWrite<WritePtr>,
-        positions_write: CompositeWrite<WritePtr>,
-        positionsidx_write: CompositeWrite<WritePtr>,
-        schema: Schema,
-    ) -> Result<InvertedIndexSerializer> {
-        Ok(InvertedIndexSerializer {
-            terms_write,
-            postings_write,
-            positions_write,
-            positionsidx_write,
+    pub(crate) fn for_segment(segment: &mut Segment) -> crate::Result<Self> {
+        let schema = segment.schema();
+        use crate::core::SegmentComponent;
+        let terms_wrt = segment.open_write(SegmentComponent::TERMS)?;
+        let postings_wrt = segment.open_write(SegmentComponent::POSTINGS)?;
+        let positions_wrt = segment.open_write(SegmentComponent::POSITIONS)?;
+        let positions_idx_wrt = segment.open_write(SegmentComponent::POSITIONSSKIP)?;
+        Ok(Self::open(
             schema,
-        })
+            terms_wrt,
+            postings_wrt,
+            positions_wrt,
+            positions_idx_wrt,
+        ))
     }
-
     /// Open a new `PostingsSerializer` for the given segment
-    pub fn open(segment: &mut Segment) -> Result<InvertedIndexSerializer> {
-        use crate::SegmentComponent::{POSITIONS, POSITIONSSKIP, POSTINGS, TERMS};
-        InvertedIndexSerializer::create(
-            CompositeWrite::wrap(segment.open_write(TERMS)?),
-            CompositeWrite::wrap(segment.open_write(POSTINGS)?),
-            CompositeWrite::wrap(segment.open_write(POSITIONS)?),
-            CompositeWrite::wrap(segment.open_write(POSITIONSSKIP)?),
-            segment.schema(),
-        )
+    pub(crate) fn open(
+        schema: Schema,
+        terms_wrt: WritePtr,
+        postings_wrt: WritePtr,
+        positions_wrt: WritePtr,
+        positions_idx_wrt: WritePtr,
+    ) -> InvertedIndexSerializer {
+        InvertedIndexSerializer {
+            terms_write: CompositeWrite::wrap(terms_wrt),
+            postings_write: CompositeWrite::wrap(postings_wrt),
+            positions_write: CompositeWrite::wrap(positions_wrt),
+            positionsidx_write: CompositeWrite::wrap(positions_idx_wrt),
+            schema,
+        }
     }
 
     /// Must be called before starting pushing terms of

src/query/query_parser/query_parser.rs

@@ -8,7 +8,7 @@ use crate::query::PhraseQuery;
 use crate::query::Query;
 use crate::query::RangeQuery;
 use crate::query::TermQuery;
-use crate::schema::IndexRecordOption;
+use crate::schema::{Facet, IndexRecordOption};
 use crate::schema::{Field, Schema};
 use crate::schema::{FieldType, Term};
 use crate::tokenizer::TokenizerManager;
@@ -319,7 +319,10 @@ impl QueryParser {
                     ))
                 }
             }
-            FieldType::HierarchicalFacet => Ok(vec![(0, Term::from_field_text(field, phrase))]),
+            FieldType::HierarchicalFacet => {
+                let facet = Facet::from_text(phrase);
+                Ok(vec![(0, Term::from_field_text(field, facet.encoded_str()))])
+            }
             FieldType::Bytes => {
                 let field_name = self.schema.get_field_name(field).to_string();
                 Err(QueryParserError::FieldNotIndexed(field_name))
@@ -554,6 +557,7 @@ mod test {
         schema_builder.add_text_field("with_stop_words", text_options);
         schema_builder.add_date_field("date", INDEXED);
         schema_builder.add_f64_field("float", INDEXED);
+        schema_builder.add_facet_field("facet");
         let schema = schema_builder.build();
         let default_fields = vec![title, text];
         let tokenizer_manager = TokenizerManager::default();
@@ -588,9 +592,13 @@ mod test {
     }
 
     #[test]
-    pub fn test_parse_query_simple() {
+    pub fn test_parse_query_facet() {
         let query_parser = make_query_parser();
-        assert!(query_parser.parse_query("toto").is_ok());
+        let query = query_parser.parse_query("facet:/root/branch/leaf").unwrap();
+        assert_eq!(
+            format!("{:?}", query),
+            "TermQuery(Term(field=11,bytes=[114, 111, 111, 116, 0, 98, 114, 97, 110, 99, 104, 0, 108, 101, 97, 102]))"
+        );
     }
 
     #[test]

src/schema/schema.rs

@@ -166,7 +166,7 @@ impl SchemaBuilder {
     }
 
     /// Adds a field entry to the schema in build.
-    fn add_field(&mut self, field_entry: FieldEntry) -> Field {
+    pub fn add_field(&mut self, field_entry: FieldEntry) -> Field {
         let field = Field::from_field_id(self.fields.len() as u32);
         let field_name = field_entry.name().to_string();
         self.fields.push(field_entry);
@@ -401,6 +401,7 @@ pub enum DocParsingError {
 mod tests {
 
     use crate::schema::field_type::ValueParsingError;
+    use crate::schema::int_options::Cardinality::SingleValue;
     use crate::schema::schema::DocParsingError::NotJSON;
     use crate::schema::*;
     use matches::{assert_matches, matches};
@@ -715,4 +716,94 @@ mod tests {
             assert_matches!(json_err, Err(NotJSON(_)));
         }
     }
+
+    #[test]
+    pub fn test_schema_add_field() {
+        let mut schema_builder = SchemaBuilder::default();
+        let id_options = TextOptions::default().set_stored().set_indexing_options(
+            TextFieldIndexing::default()
+                .set_tokenizer("raw")
+                .set_index_option(IndexRecordOption::Basic),
+        );
+        let timestamp_options = IntOptions::default()
+            .set_stored()
+            .set_indexed()
+            .set_fast(SingleValue);
+        schema_builder.add_text_field("_id", id_options);
+        schema_builder.add_date_field("_timestamp", timestamp_options);
+
+        let schema_content = r#"[
+  {
+    "name": "text",
+    "type": "text",
+    "options": {
+      "indexing": {
+        "record": "position",
+        "tokenizer": "default"
+      },
+      "stored": false
+    }
+  },
+  {
+    "name": "popularity",
+    "type": "i64",
+    "options": {
+      "indexed": false,
+      "fast": "single",
+      "stored": true
+    }
+  }
+]"#;
+        let tmp_schema: Schema =
+            serde_json::from_str(&schema_content).expect("error while reading json");
+        for (_field, field_entry) in tmp_schema.fields() {
+            schema_builder.add_field(field_entry.clone());
+        }
+
+        let schema = schema_builder.build();
+        let schema_json = serde_json::to_string_pretty(&schema).unwrap();
+        let expected = r#"[
+  {
+    "name": "_id",
+    "type": "text",
+    "options": {
+      "indexing": {
+        "record": "basic",
+        "tokenizer": "raw"
+      },
+      "stored": true
+    }
+  },
+  {
+    "name": "_timestamp",
+    "type": "date",
+    "options": {
+      "indexed": true,
+      "fast": "single",
+      "stored": true
+    }
+  },
+  {
+    "name": "text",
+    "type": "text",
+    "options": {
+      "indexing": {
+        "record": "position",
+        "tokenizer": "default"
+      },
+      "stored": false
+    }
+  },
+  {
+    "name": "popularity",
+    "type": "i64",
+    "options": {
+      "indexed": false,
+      "fast": "single",
+      "stored": true
+    }
+  }
+]"#;
+        assert_eq!(schema_json, expected);
+    }
 }

src/schema/value.rs

@@ -209,8 +209,8 @@ impl From<f64> for Value {
     }
 }
 
-impl From<DateTime> for Value {
-    fn from(date_time: DateTime) -> Value {
+impl From<crate::DateTime> for Value {
+    fn from(date_time: crate::DateTime) -> Value {
         Value::Date(date_time)
     }
 }

src/store/mod.rs

@@ -57,7 +57,7 @@ use self::compression_snap::{compress, decompress};
 pub mod tests {
 
     use super::*;
-    use crate::directory::{Directory, RAMDirectory, WritePtr};
+    use crate::directory::{Directory, RAMDirectory, ReadOnlyDirectory, WritePtr};
     use crate::schema::Document;
     use crate::schema::FieldValue;
     use crate::schema::Schema;

src/termdict/mod.rs

@@ -36,7 +36,7 @@ pub use self::termdict::{TermDictionary, TermDictionaryBuilder};
 mod tests {
     use super::{TermDictionary, TermDictionaryBuilder, TermStreamer};
     use crate::core::Index;
-    use crate::directory::{Directory, RAMDirectory, ReadOnlySource};
+    use crate::directory::{Directory, RAMDirectory, ReadOnlyDirectory, ReadOnlySource};
     use crate::postings::TermInfo;
     use crate::schema::{Document, FieldType, Schema, TEXT};
     use std::path::PathBuf;

tests/failpoints/mod.rs

@@ -1,6 +1,8 @@
 use fail;
 use std::path::Path;
-use tantivy::directory::{Directory, ManagedDirectory, RAMDirectory, TerminatingWrite};
+use tantivy::directory::{
+    Directory, ManagedDirectory, RAMDirectory, ReadOnlyDirectory, TerminatingWrite,
+};
 use tantivy::doc;
 use tantivy::schema::{Schema, TEXT};
 use tantivy::{Index, Term};