improve log levels

clippy: Remove borrows that the compiler will do.

common/src/bitset.rs

@@ -259,11 +259,7 @@ impl BitSet {
         // we do not check saturated els.
         let higher = el / 64u32;
         let lower = el % 64u32;
-        self.len += if self.tinysets[higher as usize].insert_mut(lower) {
-            1
-        } else {
-            0
-        };
+        self.len += u64::from(self.tinysets[higher as usize].insert_mut(lower));
     }
 
     /// Inserts an element in the `BitSet`
@@ -272,11 +268,7 @@ impl BitSet {
         // we do not check saturated els.
         let higher = el / 64u32;
         let lower = el % 64u32;
-        self.len -= if self.tinysets[higher as usize].remove_mut(lower) {
-            1
-        } else {
-            0
-        };
+        self.len -= u64::from(self.tinysets[higher as usize].remove_mut(lower));
     }
 
     /// Returns true iff the elements is in the `BitSet`.

common/src/serialize.rs

@@ -161,8 +161,7 @@ impl FixedSize for u8 {
 
 impl BinarySerializable for bool {
     fn serialize<W: Write>(&self, writer: &mut W) -> io::Result<()> {
-        let val = if *self { 1 } else { 0 };
-        writer.write_u8(val)
+        writer.write_u8(u8::from(*self))
     }
     fn deserialize<R: Read>(reader: &mut R) -> io::Result<bool> {
         let val = reader.read_u8()?;

fastfield_codecs/Cargo.toml

@@ -17,7 +17,7 @@ rand = {version="0.8.3", optional= true}
 fastdivide = "0.4"
 log = "0.4"
 itertools = { version = "0.10.3" }
-measure_time = { version="0.8.2", optional=true}
+measure_time = { version="0.8.2" }
 
 [dev-dependencies]
 more-asserts = "0.3.0"
@@ -25,7 +25,7 @@ proptest = "1.0.0"
 rand = "0.8.3"
 
 [features]
-bin = ["prettytable-rs", "rand", "measure_time"]
+bin = ["prettytable-rs", "rand"]
 default = ["bin"]
 unstable = []
 

fastfield_codecs/src/bitpacked.rs

@@ -75,7 +75,7 @@ impl FastFieldCodec for BitpackedCodec {
         Ok(())
     }
 
-    fn estimate(column: &impl Column) -> Option<f32> {
+    fn estimate(column: &dyn Column) -> Option<f32> {
         let num_bits = compute_num_bits(column.max_value());
         let num_bits_uncompressed = 64;
         Some(num_bits as f32 / num_bits_uncompressed as f32)

fastfield_codecs/src/blockwise_linear.rs

@@ -71,7 +71,7 @@ impl FastFieldCodec for BlockwiseLinearCodec {
     }
 
     // Estimate first_chunk and extrapolate
-    fn estimate(column: &impl crate::Column) -> Option<f32> {
+    fn estimate(column: &dyn crate::Column) -> Option<f32> {
         if column.num_vals() < 10 * CHUNK_SIZE as u64 {
             return None;
         }
@@ -100,7 +100,7 @@ impl FastFieldCodec for BlockwiseLinearCodec {
         Some(num_bits as f32 / num_bits_uncompressed as f32)
     }
 
-    fn serialize(column: &dyn crate::Column, wrt: &mut impl io::Write) -> io::Result<()> {
+    fn serialize(column: &dyn Column, wrt: &mut impl io::Write) -> io::Result<()> {
         // The BitpackedReader assumes a normalized vector.
         assert_eq!(column.min_value(), 0);
         let mut buffer = Vec::with_capacity(CHUNK_SIZE);

fastfield_codecs/src/lib.rs

@@ -123,7 +123,7 @@ trait FastFieldCodec: 'static {
     ///
     /// The column iterator should be preferred over using column `get_val` method for
     /// performance reasons.
-    fn serialize(column: &dyn Column<u64>, write: &mut impl Write) -> io::Result<()>;
+    fn serialize(column: &dyn Column, write: &mut impl Write) -> io::Result<()>;
 
     /// Returns an estimate of the compression ratio.
     /// If the codec is not applicable, returns `None`.
@@ -132,7 +132,7 @@ trait FastFieldCodec: 'static {
     ///
     /// It could make sense to also return a value representing
     /// computational complexity.
-    fn estimate(column: &impl Column) -> Option<f32>;
+    fn estimate(column: &dyn Column) -> Option<f32>;
 }
 
 pub const ALL_CODEC_TYPES: [FastFieldCodecType; 3] = [

fastfield_codecs/src/line.rs

@@ -69,11 +69,17 @@ impl Line {
 
     // Same as train, but the intercept is only estimated from provided sample positions
     pub fn estimate(ys: &dyn Column, sample_positions: &[u64]) -> Self {
-        Self::train_from(ys, sample_positions.iter().cloned())
+        Self::train_from(
+            ys,
+            sample_positions
+                .iter()
+                .cloned()
+                .map(|pos| (pos, ys.get_val(pos))),
+        )
     }
 
     // Intercept is only computed from provided positions
-    fn train_from(ys: &dyn Column, positions: impl Iterator<Item = u64>) -> Self {
+    fn train_from(ys: &dyn Column, positions_and_values: impl Iterator<Item = (u64, u64)>) -> Self {
         let num_vals = if let Some(num_vals) = NonZeroU64::new(ys.num_vals() - 1) {
             num_vals
         } else {
@@ -114,11 +120,8 @@ impl Line {
             intercept: 0,
         };
         let heuristic_shift = y0.wrapping_sub(MID_POINT);
-        line.intercept = positions
-            .map(|pos| {
-                let y = ys.get_val(pos);
-                y.wrapping_sub(line.eval(pos))
-            })
+        line.intercept = positions_and_values
+            .map(|(pos, y)| y.wrapping_sub(line.eval(pos)))
             .min_by_key(|&val| val.wrapping_sub(heuristic_shift))
             .unwrap_or(0u64); //< Never happens.
         line
@@ -135,7 +138,10 @@ impl Line {
     /// This function is only invariable by translation if all of the
     /// `ys` are packaged into half of the space. (See heuristic below)
     pub fn train(ys: &dyn Column) -> Self {
-        Self::train_from(ys, 0..ys.num_vals())
+        Self::train_from(
+            ys,
+            ys.iter().enumerate().map(|(pos, val)| (pos as u64, val)),
+        )
     }
 }
 

fastfield_codecs/src/linear.rs

@@ -121,7 +121,7 @@ impl FastFieldCodec for LinearCodec {
     /// where the local maxima for the deviation of the calculated value are and
     /// the offset to shift all values to >=0 is also unknown.
     #[allow(clippy::question_mark)]
-    fn estimate(column: &impl Column) -> Option<f32> {
+    fn estimate(column: &dyn Column) -> Option<f32> {
         if column.num_vals() < 3 {
             return None; // disable compressor for this case
         }

fastfield_codecs/src/monotonic_mapping.rs

@@ -36,11 +36,7 @@ impl MonotonicallyMappableToU64 for i64 {
 impl MonotonicallyMappableToU64 for bool {
     #[inline(always)]
     fn to_u64(self) -> u64 {
-        if self {
-            1
-        } else {
-            0
-        }
+        u64::from(self)
     }
 
     #[inline(always)]

fastfield_codecs/src/serialize.rs

@@ -23,7 +23,8 @@ use std::sync::Arc;
 
 use common::{BinarySerializable, VInt};
 use fastdivide::DividerU64;
-use log::warn;
+use log::{trace, warn};
+use measure_time::trace_time;
 use ownedbytes::OwnedBytes;
 
 use crate::bitpacked::BitpackedCodec;
@@ -183,6 +184,7 @@ fn detect_codec(
 ) -> Option<FastFieldCodecType> {
     let mut estimations = Vec::new();
     for &codec in codecs {
+        trace_time!("estimate time for codec: {:?}", codec);
         let estimation_opt = match codec {
             FastFieldCodecType::Bitpacked => BitpackedCodec::estimate(&column),
             FastFieldCodecType::Linear => LinearCodec::estimate(&column),
@@ -202,6 +204,7 @@ fn detect_codec(
     // codecs
     estimations.retain(|estimation| !estimation.0.is_nan() && estimation.0 != f32::MAX);
     estimations.sort_by(|(score_left, _), (score_right, _)| score_left.total_cmp(score_right));
+    trace!("Chosen Codec {:?}", estimations.first()?.1);
     Some(estimations.first()?.1)
 }
 
@@ -210,6 +213,12 @@ fn serialize_given_codec(
     codec_type: FastFieldCodecType,
     output: &mut impl io::Write,
 ) -> io::Result<()> {
+    trace_time!(
+        "Serialize time for codec: {:?}, num_vals {}",
+        codec_type,
+        column.num_vals()
+    );
+
     match codec_type {
         FastFieldCodecType::Bitpacked => {
             BitpackedCodec::serialize(&column, output)?;

src/aggregation/bucket/histogram/histogram.rs

@@ -425,7 +425,7 @@ impl SegmentHistogramCollector {
         let bucket = &mut self.buckets[bucket_pos];
         bucket.doc_count += 1;
         if let Some(sub_aggregation) = self.sub_aggregations.as_mut() {
-            (&mut sub_aggregation[bucket_pos]).collect(doc, bucket_with_accessor)?;
+            sub_aggregation[bucket_pos].collect(doc, bucket_with_accessor)?;
         }
         Ok(())
     }

src/core/segment_id.rs

@@ -57,7 +57,7 @@ impl SegmentId {
     /// Picking the first 8 chars is ok to identify
     /// segments in a display message (e.g. a5c4dfcb).
     pub fn short_uuid_string(&self) -> String {
-        (&self.0.as_simple().to_string()[..8]).to_string()
+        self.0.as_simple().to_string()[..8].to_string()
     }
 
     /// Returns a segment uuid string.

src/directory/mmap_directory.rs

@@ -472,6 +472,8 @@ mod tests {
     // There are more tests in directory/mod.rs
     // The following tests are specific to the MmapDirectory
 
+    use std::time::Duration;
+
     use common::HasLen;
 
     use super::*;
@@ -610,7 +612,14 @@ mod tests {
                 mmap_directory.get_cache_info().mmapped.len()
             );
         }
-        assert!(mmap_directory.get_cache_info().mmapped.is_empty());
-        Ok(())
+        // This test failed on CI. The last Mmap is dropped from the merging thread so there might
+        // be a race condition indeed.
+        for _ in 0..10 {
+            if mmap_directory.get_cache_info().mmapped.is_empty() {
+                return Ok(());
+            }
+            std::thread::sleep(Duration::from_millis(200));
+        }
+        panic!("The cache still contains information. One of the Mmap has not been dropped.");
     }
 }

src/directory/ram_directory.rs

@@ -136,6 +136,20 @@ impl RamDirectory {
         Self::default()
     }
 
+    /// Deep clones the directory.
+    ///
+    /// Ulterior writes on one of the copy
+    /// will not affect the other copy.
+    pub fn deep_clone(&self) -> RamDirectory {
+        let inner_clone = InnerDirectory {
+            fs: self.fs.read().unwrap().fs.clone(),
+            watch_router: Default::default(),
+        };
+        RamDirectory {
+            fs: Arc::new(RwLock::new(inner_clone)),
+        }
+    }
+
     /// Returns the sum of the size of the different files
     /// in the [`RamDirectory`].
     pub fn total_mem_usage(&self) -> usize {
@@ -256,4 +270,23 @@ mod tests {
         assert_eq!(directory_copy.atomic_read(path_atomic).unwrap(), msg_atomic);
         assert_eq!(directory_copy.atomic_read(path_seq).unwrap(), msg_seq);
     }
+
+    #[test]
+    fn test_ram_directory_deep_clone() {
+        let dir = RamDirectory::default();
+        let test = Path::new("test");
+        let test2 = Path::new("test2");
+        dir.atomic_write(test, b"firstwrite").unwrap();
+        let dir_clone = dir.deep_clone();
+        assert_eq!(
+            dir_clone.atomic_read(test).unwrap(),
+            dir.atomic_read(test).unwrap()
+        );
+        dir.atomic_write(test, b"original").unwrap();
+        dir_clone.atomic_write(test, b"clone").unwrap();
+        dir_clone.atomic_write(test2, b"clone2").unwrap();
+        assert_eq!(dir.atomic_read(test).unwrap(), b"original");
+        assert_eq!(&dir_clone.atomic_read(test).unwrap(), b"clone");
+        assert_eq!(&dir_clone.atomic_read(test2).unwrap(), b"clone2");
+    }
 }

src/fastfield/multivalued/mod.rs

@@ -402,6 +402,74 @@ mod bench {
     use crate::schema::{Cardinality, NumericOptions, Schema};
     use crate::Document;
 
+    fn bench_multi_value_ff_merge_opt(
+        num_docs: usize,
+        segments_every_n_docs: usize,
+        merge_policy: impl crate::indexer::MergePolicy + 'static,
+    ) {
+        let mut builder = crate::schema::SchemaBuilder::new();
+
+        let fast_multi =
+            crate::schema::NumericOptions::default().set_fast(Cardinality::MultiValues);
+        let multi_field = builder.add_f64_field("f64s", fast_multi);
+
+        let index = crate::Index::create_in_ram(builder.build());
+
+        let mut writer = index.writer_for_tests().unwrap();
+        writer.set_merge_policy(Box::new(merge_policy));
+
+        for i in 0..num_docs {
+            let mut doc = crate::Document::new();
+            doc.add_f64(multi_field, 0.24);
+            doc.add_f64(multi_field, 0.27);
+            doc.add_f64(multi_field, 0.37);
+            if i % 3 == 0 {
+                doc.add_f64(multi_field, 0.44);
+            }
+
+            writer.add_document(doc).unwrap();
+            if i % segments_every_n_docs == 0 {
+                writer.commit().unwrap();
+            }
+        }
+
+        {
+            writer.wait_merging_threads().unwrap();
+            let mut writer = index.writer_for_tests().unwrap();
+            let segment_ids = index.searchable_segment_ids().unwrap();
+            writer.merge(&segment_ids).wait().unwrap();
+        }
+
+        // If a merging thread fails, we should end up with more
+        // than one segment here
+        assert_eq!(1, index.searchable_segments().unwrap().len());
+    }
+
+    #[bench]
+    fn bench_multi_value_ff_merge_many_segments(b: &mut Bencher) {
+        let num_docs = 100_000;
+        b.iter(|| {
+            bench_multi_value_ff_merge_opt(num_docs, 1_000, crate::indexer::NoMergePolicy);
+        });
+    }
+
+    #[bench]
+    fn bench_multi_value_ff_merge_many_segments_log_merge(b: &mut Bencher) {
+        let num_docs = 100_000;
+        b.iter(|| {
+            let merge_policy = crate::indexer::LogMergePolicy::default();
+            bench_multi_value_ff_merge_opt(num_docs, 1_000, merge_policy);
+        });
+    }
+
+    #[bench]
+    fn bench_multi_value_ff_merge_few_segments(b: &mut Bencher) {
+        let num_docs = 100_000;
+        b.iter(|| {
+            bench_multi_value_ff_merge_opt(num_docs, 33_000, crate::indexer::NoMergePolicy);
+        });
+    }
+
     fn multi_values(num_docs: usize, vals_per_doc: usize) -> Vec<Vec<u64>> {
         let mut vals = vec![];
         for _i in 0..num_docs {

src/fastfield/multivalued/writer.rs

@@ -3,6 +3,7 @@ use std::sync::Mutex;
 
 use fastfield_codecs::{Column, MonotonicallyMappableToU64, VecColumn};
 use fnv::FnvHashMap;
+use measure_time::{debug_time, trace_time};
 
 use crate::fastfield::{value_to_u64, CompositeFastFieldSerializer, FastFieldType};
 use crate::indexer::doc_id_mapping::DocIdMapping;
@@ -146,6 +147,13 @@ impl MultiValuedFastFieldWriter {
         {
             self.doc_index.push(self.vals.len() as u64);
             let col = VecColumn::from(&self.doc_index[..]);
+
+            trace_time!(
+                "segment-serialize-multi-fast-field-idx, num_vals {}, field_id {:?}",
+                col.num_vals(),
+                self.field()
+            );
+
             if let Some(doc_id_map) = doc_id_map {
                 let multi_value_start_index = MultivalueStartIndex::new(&col, doc_id_map);
                 serializer.create_auto_detect_u64_fast_field_with_idx(
@@ -158,6 +166,12 @@ impl MultiValuedFastFieldWriter {
             }
         }
         {
+            trace_time!(
+                "segment-serialize-multi-fast-field-values, num_vals {}, field_id {:?}",
+                self.vals.len(),
+                self.field()
+            );
+
             // Writing the values themselves.
             // TODO FIXME: Use less memory.
             let mut values: Vec<u64> = Vec::new();

src/fastfield/writer.rs

@@ -4,6 +4,7 @@ use std::io;
 use common;
 use fastfield_codecs::{Column, MonotonicallyMappableToU64};
 use fnv::FnvHashMap;
+use measure_time::{debug_time, trace_time};
 use tantivy_bitpacker::BlockedBitpacker;
 
 use super::multivalued::MultiValuedFastFieldWriter;
@@ -215,6 +216,7 @@ impl FastFieldsWriter {
         mapping: &HashMap<Field, FnvHashMap<UnorderedTermId, TermOrdinal>>,
         doc_id_map: Option<&DocIdMapping>,
     ) -> io::Result<()> {
+        debug_time!("segment-serialize-all-fast-fields",);
         for field_writer in self.term_id_writers {
             let field = field_writer.field();
             field_writer.serialize(serializer, mapping.get(&field), doc_id_map)?;
@@ -367,6 +369,11 @@ impl IntFastFieldWriter {
             num_vals: self.val_count as u64,
         };
 
+        trace_time!(
+            "segment-serialize-single-value-field, field_id {:?}",
+            self.field()
+        );
+
         serializer.create_auto_detect_u64_fast_field(self.field, fastfield_accessor)?;
 
         Ok(())

src/indexer/delete_queue.rs

@@ -246,18 +246,27 @@ impl DeleteCursor {
 mod tests {
 
     use super::{DeleteOperation, DeleteQueue};
-    use crate::schema::{Field, Term};
+    use crate::query::{Explanation, Scorer, Weight};
+    use crate::{DocId, Score, SegmentReader};
+
+    struct DummyWeight;
+    impl Weight for DummyWeight {
+        fn scorer(&self, _reader: &SegmentReader, _boost: Score) -> crate::Result<Box<dyn Scorer>> {
+            Err(crate::TantivyError::InternalError("dummy impl".to_owned()))
+        }
+
+        fn explain(&self, _reader: &SegmentReader, _doc: DocId) -> crate::Result<Explanation> {
+            Err(crate::TantivyError::InternalError("dummy impl".to_owned()))
+        }
+    }
 
     #[test]
     fn test_deletequeue() {
         let delete_queue = DeleteQueue::new();
 
-        let make_op = |i: usize| {
-            let field = Field::from_field_id(1u32);
-            DeleteOperation {
-                opstamp: i as u64,
-                term: Term::from_field_u64(field, i as u64),
-            }
+        let make_op = |i: usize| DeleteOperation {
+            opstamp: i as u64,
+            target: Box::new(DummyWeight),
         };
 
         delete_queue.push(make_op(1));

src/indexer/index_writer.rs

@@ -11,7 +11,6 @@ use super::segment_updater::SegmentUpdater;
 use super::{AddBatch, AddBatchReceiver, AddBatchSender, PreparedCommit};
 use crate::core::{Index, Segment, SegmentComponent, SegmentId, SegmentMeta, SegmentReader};
 use crate::directory::{DirectoryLock, GarbageCollectionResult, TerminatingWrite};
-use crate::docset::{DocSet, TERMINATED};
 use crate::error::TantivyError;
 use crate::fastfield::write_alive_bitset;
 use crate::indexer::delete_queue::{DeleteCursor, DeleteQueue};
@@ -20,8 +19,9 @@ use crate::indexer::index_writer_status::IndexWriterStatus;
 use crate::indexer::operation::DeleteOperation;
 use crate::indexer::stamper::Stamper;
 use crate::indexer::{MergePolicy, SegmentEntry, SegmentWriter};
+use crate::query::{Query, TermQuery};
 use crate::schema::{Document, IndexRecordOption, Term};
-use crate::{FutureResult, Opstamp};
+use crate::{FutureResult, IndexReader, Opstamp};
 
 // Size of the margin for the `memory_arena`. A segment is closed when the remaining memory
 // in the `memory_arena` goes below MARGIN_IN_BYTES.
@@ -57,6 +57,7 @@ pub struct IndexWriter {
     _directory_lock: Option<DirectoryLock>,
 
     index: Index,
+    index_reader: IndexReader,
 
     memory_arena_in_bytes_per_thread: usize,
 
@@ -92,19 +93,14 @@ fn compute_deleted_bitset(
 
         // A delete operation should only affect
         // document that were inserted before it.
-        let inverted_index = segment_reader.inverted_index(delete_op.term.field())?;
-        if let Some(mut docset) =
-            inverted_index.read_postings(&delete_op.term, IndexRecordOption::Basic)?
-        {
-            let mut doc_matching_deleted_term = docset.doc();
-            while doc_matching_deleted_term != TERMINATED {
-                if doc_opstamps.is_deleted(doc_matching_deleted_term, delete_op.opstamp) {
-                    alive_bitset.remove(doc_matching_deleted_term);
+        delete_op
+            .target
+            .for_each(segment_reader, &mut |doc_matching_delete_query, _| {
+                if doc_opstamps.is_deleted(doc_matching_delete_query, delete_op.opstamp) {
+                    alive_bitset.remove(doc_matching_delete_query);
                     might_have_changed = true;
                 }
-                doc_matching_deleted_term = docset.advance();
-            }
-        }
+            })?;
         delete_cursor.advance();
     }
     Ok(might_have_changed)
@@ -302,6 +298,7 @@ impl IndexWriter {
 
             memory_arena_in_bytes_per_thread,
             index: index.clone(),
+            index_reader: index.reader()?,
 
             index_writer_status: IndexWriterStatus::from(document_receiver),
             operation_sender: document_sender,
@@ -666,10 +663,33 @@ impl IndexWriter {
     /// Like adds, the deletion itself will be visible
     /// only after calling `commit()`.
     pub fn delete_term(&self, term: Term) -> Opstamp {
+        let query = TermQuery::new(term, IndexRecordOption::Basic);
+        // For backward compatibility, if Term is invalid for the index, do nothing but return an
+        // Opstamp
+        self.delete_query(Box::new(query))
+            .unwrap_or_else(|_| self.stamper.stamp())
+    }
+
+    /// Delete all documents matching a given query.
+    /// Returns an `Err` if the query can't be executed.
+    ///
+    /// Delete operation only affects documents that
+    /// were added in previous commits, and documents
+    /// that were added previously in the same commit.
+    ///
+    /// Like adds, the deletion itself will be visible
+    /// only after calling `commit()`.
+    #[doc(hidden)]
+    pub fn delete_query(&self, query: Box<dyn Query>) -> crate::Result<Opstamp> {
+        let weight = query.weight(&self.index_reader.searcher(), false)?;
+
         let opstamp = self.stamper.stamp();
-        let delete_operation = DeleteOperation { opstamp, term };
+        let delete_operation = DeleteOperation {
+            opstamp,
+            target: weight,
+        };
         self.delete_queue.push(delete_operation);
-        opstamp
+        Ok(opstamp)
     }
 
     /// Returns the opstamp of the last successful commit.
@@ -738,10 +758,17 @@ impl IndexWriter {
         let (batch_opstamp, stamps) = self.get_batch_opstamps(count);
 
         let mut adds = AddBatch::default();
+
         for (user_op, opstamp) in user_operations_it.zip(stamps) {
             match user_op {
                 UserOperation::Delete(term) => {
-                    let delete_operation = DeleteOperation { opstamp, term };
+                    let query = TermQuery::new(term, IndexRecordOption::Basic);
+                    let weight = query.weight(&self.index_reader.searcher(), false)?;
+
+                    let delete_operation = DeleteOperation {
+                        opstamp,
+                        target: weight,
+                    };
                     self.delete_queue.push(delete_operation);
                 }
                 UserOperation::Add(document) => {
@@ -786,7 +813,7 @@ mod tests {
     use crate::directory::error::LockError;
     use crate::error::*;
     use crate::indexer::NoMergePolicy;
-    use crate::query::{QueryParser, TermQuery};
+    use crate::query::{BooleanQuery, Occur, Query, QueryParser, TermQuery};
     use crate::schema::{
         self, Cardinality, Facet, FacetOptions, IndexRecordOption, NumericOptions,
         TextFieldIndexing, TextOptions, FAST, INDEXED, STORED, STRING, TEXT,
@@ -1418,10 +1445,72 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn test_delete_query_with_sort_by_field() -> crate::Result<()> {
+        let mut schema_builder = schema::Schema::builder();
+        let id_field =
+            schema_builder.add_u64_field("id", schema::INDEXED | schema::STORED | schema::FAST);
+        let schema = schema_builder.build();
+
+        let settings = IndexSettings {
+            sort_by_field: Some(IndexSortByField {
+                field: "id".to_string(),
+                order: Order::Desc,
+            }),
+            ..Default::default()
+        };
+
+        let index = Index::builder()
+            .schema(schema)
+            .settings(settings)
+            .create_in_ram()?;
+        let index_reader = index.reader()?;
+        let mut index_writer = index.writer_for_tests()?;
+
+        // create and delete docs in same commit
+        for id in 0u64..5u64 {
+            index_writer.add_document(doc!(id_field => id))?;
+        }
+        for id in 1u64..4u64 {
+            let term = Term::from_field_u64(id_field, id);
+            let not_term = Term::from_field_u64(id_field, 2);
+            let term = Box::new(TermQuery::new(term, Default::default()));
+            let not_term = Box::new(TermQuery::new(not_term, Default::default()));
+
+            let query: BooleanQuery = vec![
+                (Occur::Must, term as Box<dyn Query>),
+                (Occur::MustNot, not_term as Box<dyn Query>),
+            ]
+            .into();
+
+            index_writer.delete_query(Box::new(query))?;
+        }
+        for id in 5u64..10u64 {
+            index_writer.add_document(doc!(id_field => id))?;
+        }
+        index_writer.commit()?;
+        index_reader.reload()?;
+
+        let searcher = index_reader.searcher();
+        assert_eq!(searcher.segment_readers().len(), 1);
+
+        let segment_reader = searcher.segment_reader(0);
+        assert_eq!(segment_reader.num_docs(), 8);
+        assert_eq!(segment_reader.max_doc(), 10);
+        let fast_field_reader = segment_reader.fast_fields().u64(id_field)?;
+        let in_order_alive_ids: Vec<u64> = segment_reader
+            .doc_ids_alive()
+            .map(|doc| fast_field_reader.get_val(doc as u64))
+            .collect();
+        assert_eq!(&in_order_alive_ids[..], &[9, 8, 7, 6, 5, 4, 2, 0]);
+        Ok(())
+    }
+
     #[derive(Debug, Clone, Copy)]
     enum IndexingOp {
         AddDoc { id: u64 },
         DeleteDoc { id: u64 },
+        DeleteDocQuery { id: u64 },
         Commit,
         Merge,
     }
@@ -1429,6 +1518,7 @@ mod tests {
     fn balanced_operation_strategy() -> impl Strategy<Value = IndexingOp> {
         prop_oneof![
             (0u64..20u64).prop_map(|id| IndexingOp::DeleteDoc { id }),
+            (0u64..20u64).prop_map(|id| IndexingOp::DeleteDocQuery { id }),
             (0u64..20u64).prop_map(|id| IndexingOp::AddDoc { id }),
             (0u64..1u64).prop_map(|_| IndexingOp::Commit),
             (0u64..1u64).prop_map(|_| IndexingOp::Merge),
@@ -1437,7 +1527,8 @@ mod tests {
 
     fn adding_operation_strategy() -> impl Strategy<Value = IndexingOp> {
         prop_oneof![
-            10 => (0u64..100u64).prop_map(|id| IndexingOp::DeleteDoc { id }),
+            5 => (0u64..100u64).prop_map(|id| IndexingOp::DeleteDoc { id }),
+            5 => (0u64..100u64).prop_map(|id| IndexingOp::DeleteDocQuery { id }),
             50 => (0u64..100u64).prop_map(|id| IndexingOp::AddDoc { id }),
             2 => (0u64..1u64).prop_map(|_| IndexingOp::Commit),
             1 => (0u64..1u64).prop_map(|_| IndexingOp::Merge),
@@ -1457,6 +1548,10 @@ mod tests {
                     existing_ids.remove(&id);
                     deleted_ids.insert(id);
                 }
+                IndexingOp::DeleteDocQuery { id } => {
+                    existing_ids.remove(&id);
+                    deleted_ids.insert(id);
+                }
                 _ => {}
             }
         }
@@ -1539,6 +1634,11 @@ mod tests {
                 IndexingOp::DeleteDoc { id } => {
                     index_writer.delete_term(Term::from_field_u64(id_field, id));
                 }
+                IndexingOp::DeleteDocQuery { id } => {
+                    let term = Term::from_field_u64(id_field, id);
+                    let query = TermQuery::new(term, Default::default());
+                    index_writer.delete_query(Box::new(query))?;
+                }
                 IndexingOp::Commit => {
                     index_writer.commit()?;
                 }

src/indexer/merger.rs

@@ -4,7 +4,7 @@ use std::sync::Arc;
 
 use fastfield_codecs::VecColumn;
 use itertools::Itertools;
-use measure_time::debug_time;
+use measure_time::{debug_time, trace_time};
 
 use crate::core::{Segment, SegmentReader};
 use crate::docset::{DocSet, TERMINATED};
@@ -250,7 +250,11 @@ impl IndexMerger {
         mut term_ord_mappings: HashMap<Field, TermOrdinalMapping>,
         doc_id_mapping: &SegmentDocIdMapping,
     ) -> crate::Result<()> {
-        debug_time!("write-fast-fields");
+        debug_time!(
+            "merge-all-fast-fields, num_segments {}, num docs new segment {}",
+            self.readers.len(),
+            doc_id_mapping.len()
+        );
 
         for (field, field_entry) in self.schema.fields() {
             let field_type = field_entry.field_type();
@@ -311,6 +315,12 @@ impl IndexMerger {
         doc_id_mapping: &SegmentDocIdMapping,
     ) -> crate::Result<()> {
         let fast_field_accessor = SortedDocIdColumn::new(&self.readers, doc_id_mapping, field);
+        trace_time!(
+            "merge-single-fast-field, num_vals {}, num_segments {}, field_id {:?}",
+            fast_field_accessor.num_vals(),
+            self.readers.len(),
+            field
+        );
         fast_field_serializer.create_auto_detect_u64_fast_field(field, fast_field_accessor)?;
 
         Ok(())
@@ -458,6 +468,12 @@ impl IndexMerger {
         fast_field_serializer: &mut CompositeFastFieldSerializer,
         doc_id_mapping: &SegmentDocIdMapping,
     ) -> crate::Result<Vec<u64>> {
+        trace_time!(
+            "merge-multi-fast-field-idx, num_segments {}, field_id {:?}",
+            self.readers.len(),
+            field
+        );
+
         let reader_ordinal_and_field_accessors = self
             .readers
             .iter()
@@ -488,7 +504,7 @@ impl IndexMerger {
         fast_field_serializer: &mut CompositeFastFieldSerializer,
         doc_id_mapping: &SegmentDocIdMapping,
     ) -> crate::Result<()> {
-        debug_time!("write-term-id-fast-field");
+        trace_time!("write-term-id-fast-field");
 
         // Multifastfield consists of 2 fastfields.
         // The first serves as an index into the second one and is strictly increasing.
@@ -571,6 +587,13 @@ impl IndexMerger {
 
         let fastfield_accessor =
             SortedDocIdMultiValueColumn::new(&self.readers, doc_id_mapping, &offsets, field);
+        trace_time!(
+            "merge-multi-fast-field-values, num_vals {}, num_segments {}, field_id {:?}",
+            fastfield_accessor.num_vals(),
+            self.readers.len(),
+            field
+        );
+
         fast_field_serializer.create_auto_detect_u64_fast_field_with_idx(
             field,
             fastfield_accessor,
@@ -624,7 +647,7 @@ impl IndexMerger {
         fieldnorm_reader: Option<FieldNormReader>,
         doc_id_mapping: &SegmentDocIdMapping,
     ) -> crate::Result<Option<TermOrdinalMapping>> {
-        debug_time!("write-postings-for-field");
+        debug_time!("write-postings-for-field {:?}", indexed_field);
         let mut positions_buffer: Vec<u32> = Vec::with_capacity(1_000);
         let mut delta_computer = DeltaComputer::new();
 
@@ -827,7 +850,7 @@ impl IndexMerger {
         debug!("write-storable-field");
 
         if !doc_id_mapping.is_trivial() {
-            debug!("non-trivial-doc-id-mapping");
+            debug!("non-trivial-doc-id-mapping (index is sorted)");
 
             let store_readers: Vec<_> = self
                 .readers
@@ -855,7 +878,7 @@ impl IndexMerger {
                 }
             }
         } else {
-            debug!("trivial-doc-id-mapping");
+            debug!("trivial-doc-id-mapping (index is not sorted)");
             for reader in &self.readers {
                 let store_reader = reader.get_store_reader(1)?;
                 if reader.has_deletes()

src/indexer/operation.rs

@@ -1,20 +1,11 @@
+use crate::query::Weight;
 use crate::schema::{Document, Term};
 use crate::Opstamp;
 
 /// Timestamped Delete operation.
-#[derive(Clone, Eq, PartialEq, Debug)]
 pub struct DeleteOperation {
     pub opstamp: Opstamp,
-    pub term: Term,
-}
-
-impl Default for DeleteOperation {
-    fn default() -> Self {
-        DeleteOperation {
-            opstamp: 0u64,
-            term: Term::new(),
-        }
-    }
+    pub target: Box<dyn Weight>,
 }
 
 /// Timestamped Add operation.