Make the FieldsIdsMap serialization more stable by using a BTreeMap

src/fields_ids_map.rs

@@ -1,9 +1,9 @@
-use std::collections::{HashMap, BTreeMap};
+use std::collections::BTreeMap;
 use serde::{Serialize, Deserialize};
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct FieldsIdsMap {
-    names_ids: HashMap<String, u8>,
+    names_ids: BTreeMap<String, u8>,
     ids_names: BTreeMap<u8, String>,
     next_id: Option<u8>,
 }
@@ -11,7 +11,7 @@ pub struct FieldsIdsMap {
 impl FieldsIdsMap {
     pub fn new() -> FieldsIdsMap {
         FieldsIdsMap {
-            names_ids: HashMap::new(),
+            names_ids: BTreeMap::new(),
             ids_names: BTreeMap::new(),
             next_id: Some(0),
         }
@@ -66,6 +66,12 @@ impl FieldsIdsMap {
     }
 }
 
+impl Default for FieldsIdsMap {
+    fn default() -> FieldsIdsMap {
+        FieldsIdsMap::new()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/heed_codec/csv_string_record_codec.rs

@@ -1,26 +0,0 @@
-use std::borrow::Cow;
-use csv::{StringRecord, Writer, ReaderBuilder};
-
-pub struct CsvStringRecordCodec;
-
-impl heed::BytesDecode<'_> for CsvStringRecordCodec {
-    type DItem = StringRecord;
-
-    fn bytes_decode(bytes: &[u8]) -> Option<Self::DItem> {
-        let mut reader = ReaderBuilder::new()
-            .has_headers(false)
-            .buffer_capacity(bytes.len()) // we will just read this record
-            .from_reader(bytes);
-        reader.records().next()?.ok() // it return an Option of Result
-    }
-}
-
-impl heed::BytesEncode<'_> for CsvStringRecordCodec {
-    type EItem = StringRecord;
-
-    fn bytes_encode(item: &Self::EItem) -> Option<Cow<[u8]>> {
-        let mut writer = Writer::from_writer(Vec::new());
-        writer.write_record(item).ok()?;
-        writer.into_inner().ok().map(Cow::Owned)
-    }
-}

src/heed_codec/mod.rs

@@ -1,7 +1,6 @@
 mod beu32_str_codec;
 mod bo_roaring_bitmap_codec;
 mod cbo_roaring_bitmap_codec;
-mod csv_string_record_codec;
 mod obkv_codec;
 mod roaring_bitmap_codec;
 mod str_str_u8_codec;
@@ -9,7 +8,6 @@ mod str_str_u8_codec;
 pub use self::beu32_str_codec::BEU32StrCodec;
 pub use self::bo_roaring_bitmap_codec::BoRoaringBitmapCodec;
 pub use self::cbo_roaring_bitmap_codec::CboRoaringBitmapCodec;
-pub use self::csv_string_record_codec::CsvStringRecordCodec;
 pub use self::obkv_codec::ObkvCodec;
 pub use self::roaring_bitmap_codec::RoaringBitmapCodec;
 pub use self::str_str_u8_codec::StrStrU8Codec;

src/index.rs

@@ -1,23 +1,23 @@
 use anyhow::Context;
-use csv::StringRecord;
 use heed::types::*;
 use heed::{PolyDatabase, Database};
 use roaring::RoaringBitmap;
 
 use crate::Search;
 use crate::{BEU32, DocumentId};
+use crate::fields_ids_map::FieldsIdsMap;
 use crate::{
     RoaringBitmapCodec, BEU32StrCodec, StrStrU8Codec, ObkvCodec,
-    CsvStringRecordCodec, BoRoaringBitmapCodec, CboRoaringBitmapCodec,
+    BoRoaringBitmapCodec, CboRoaringBitmapCodec,
 };
 
 pub const WORDS_FST_KEY: &str = "words-fst";
-pub const HEADERS_KEY: &str = "headers";
+pub const FIELDS_IDS_MAP_KEY: &str = "fields-ids-map";
 pub const DOCUMENTS_IDS_KEY: &str = "documents-ids";
 
 #[derive(Clone)]
 pub struct Index {
-    /// Contains many different types (e.g. the documents CSV headers).
+    /// Contains many different types (e.g. the fields ids map).
     pub main: PolyDatabase,
     /// A word and all the documents ids containing the word.
     pub word_docids: Database<Str, RoaringBitmapCodec>,
@@ -25,7 +25,7 @@ pub struct Index {
     pub docid_word_positions: Database<BEU32StrCodec, BoRoaringBitmapCodec>,
     /// Maps the proximity between a pair of words with all the docids where this relation appears.
     pub word_pair_proximity_docids: Database<StrStrU8Codec, CboRoaringBitmapCodec>,
-    /// Maps the document id to the document as a CSV line.
+    /// Maps the document id to the document as an obkv store.
     pub documents: Database<OwnedType<BEU32>, ObkvCodec>,
 }
 
@@ -44,17 +44,17 @@ impl Index {
         Ok(self.main.get::<_, Str, RoaringBitmapCodec>(rtxn, DOCUMENTS_IDS_KEY)?)
     }
 
-    pub fn put_headers(&self, wtxn: &mut heed::RwTxn, headers: &StringRecord) -> heed::Result<()> {
+    pub fn put_fields_ids_map(&self, wtxn: &mut heed::RwTxn, map: &FieldsIdsMap) -> heed::Result<()> {
-        self.main.put::<_, Str, CsvStringRecordCodec>(wtxn, HEADERS_KEY, headers)
+        self.main.put::<_, Str, SerdeJson<FieldsIdsMap>>(wtxn, FIELDS_IDS_MAP_KEY, map)
     }
 
-    pub fn headers(&self, rtxn: &heed::RoTxn) -> heed::Result<Option<StringRecord>> {
+    pub fn fields_ids_map(&self, rtxn: &heed::RoTxn) -> heed::Result<Option<FieldsIdsMap>> {
-        self.main.get::<_, Str, CsvStringRecordCodec>(rtxn, HEADERS_KEY)
+        self.main.get::<_, Str, SerdeJson<FieldsIdsMap>>(rtxn, FIELDS_IDS_MAP_KEY)
     }
 
-    pub fn number_of_attributes(&self, rtxn: &heed::RoTxn) -> anyhow::Result<Option<usize>> {
+    pub fn number_of_fields(&self, rtxn: &heed::RoTxn) -> anyhow::Result<Option<usize>> {
-        match self.headers(rtxn)? {
+        match self.fields_ids_map(rtxn)? {
-            Some(headers) => Ok(Some(headers.len())),
+            Some(map) => Ok(Some(map.len())),
             None => Ok(None),
         }
     }

src/indexing/merge_function.rs

@@ -1,6 +1,6 @@
 use std::borrow::Cow;
 
-use anyhow::bail;
+use anyhow::{bail, ensure};
 use bstr::ByteSlice as _;
 use fst::IntoStreamer;
 use roaring::RoaringBitmap;
@@ -8,7 +8,7 @@ use roaring::RoaringBitmap;
 use crate::heed_codec::CboRoaringBitmapCodec;
 
 const WORDS_FST_KEY: &[u8] = crate::index::WORDS_FST_KEY.as_bytes();
-const HEADERS_KEY: &[u8] = crate::index::HEADERS_KEY.as_bytes();
+const FIELDS_IDS_MAP_KEY: &[u8] = crate::index::FIELDS_IDS_MAP_KEY.as_bytes();
 const DOCUMENTS_IDS_KEY: &[u8] = crate::index::DOCUMENTS_IDS_KEY.as_bytes();
 
 pub fn main_merge(key: &[u8], values: &[Cow<[u8]>]) -> anyhow::Result<Vec<u8>> {
@@ -25,8 +25,8 @@ pub fn main_merge(key: &[u8], values: &[Cow<[u8]>]) -> anyhow::Result<Vec<u8>> {
             build.extend_stream(op.into_stream()).unwrap();
             Ok(build.into_inner().unwrap())
         },
-        HEADERS_KEY => {
+        FIELDS_IDS_MAP_KEY => {
-            assert!(values.windows(2).all(|vs| vs[0] == vs[1]));
+            ensure!(values.windows(2).all(|vs| vs[0] == vs[1]), "fields ids map doesn't match");
             Ok(values[0].to_vec())
         },
         DOCUMENTS_IDS_KEY => word_docids_merge(&[], values),

src/indexing/store.rs

@@ -16,7 +16,8 @@ use grenad::{Reader, FileFuse, Writer, Sorter, CompressionType};
 use roaring::RoaringBitmap;
 use tempfile::tempfile;
 
-use crate::heed_codec::{CsvStringRecordCodec, BoRoaringBitmapCodec, CboRoaringBitmapCodec};
+use crate::fields_ids_map::FieldsIdsMap;
+use crate::heed_codec::{BoRoaringBitmapCodec, CboRoaringBitmapCodec};
 use crate::tokenizer::{simple_tokenizer, only_token};
 use crate::{SmallVec32, Position, DocumentId};
 
@@ -30,7 +31,7 @@ const MAX_POSITION: usize = 1000;
 const MAX_ATTRIBUTES: usize = u32::max_value() as usize / MAX_POSITION;
 
 const WORDS_FST_KEY: &[u8] = crate::index::WORDS_FST_KEY.as_bytes();
-const HEADERS_KEY: &[u8] = crate::index::HEADERS_KEY.as_bytes();
+const FIELDS_IDS_MAP_KEY: &[u8] = crate::index::FIELDS_IDS_MAP_KEY.as_bytes();
 const DOCUMENTS_IDS_KEY: &[u8] = crate::index::DOCUMENTS_IDS_KEY.as_bytes();
 
 pub struct Readers {
@@ -182,10 +183,10 @@ impl Store {
         Ok(())
     }
 
-    fn write_headers(&mut self, headers: &StringRecord) -> anyhow::Result<()> {
+    fn write_fields_ids_map(&mut self, map: &FieldsIdsMap) -> anyhow::Result<()> {
-        let headers = CsvStringRecordCodec::bytes_encode(headers)
+        let bytes = serde_json::to_vec(&map)?;
-            .with_context(|| format!("could not encode csv record"))?;
+        self.main_sorter.insert(FIELDS_IDS_MAP_KEY, bytes)?;
-        Ok(self.main_sorter.insert(HEADERS_KEY, headers)?)
+        Ok(())
     }
 
     fn write_document(
@@ -320,7 +321,12 @@ impl Store {
 
         // Write the headers into the store.
         let headers = rdr.headers()?;
-        self.write_headers(&headers)?;
+
+        let mut fields_ids_map = FieldsIdsMap::new();
+        for header in headers.iter() {
+            fields_ids_map.insert(header).context("no more field id available")?;
+        }
+        self.write_fields_ids_map(&fields_ids_map)?;
 
         let mut before = Instant::now();
         let mut document_id: usize = base_document_id;

src/lib.rs

@@ -20,8 +20,8 @@ pub use self::index::Index;
 pub use self::search::{Search, SearchResult};
 pub use self::update_store::UpdateStore;
 pub use self::heed_codec::{
-    RoaringBitmapCodec, BEU32StrCodec, StrStrU8Codec, ObkvCodec,
+    RoaringBitmapCodec, BEU32StrCodec, StrStrU8Codec,
-    CsvStringRecordCodec, BoRoaringBitmapCodec, CboRoaringBitmapCodec,
+    ObkvCodec, BoRoaringBitmapCodec, CboRoaringBitmapCodec,
 };
 
 pub type FastMap4<K, V> = HashMap<K, V, BuildHasherDefault<FxHasher32>>;

src/subcommand/search.rs

@@ -1,8 +1,10 @@
+use std::collections::HashMap;
 use std::io::{self, BufRead};
 use std::iter::once;
 use std::path::PathBuf;
 use std::time::Instant;
 
+use anyhow::Context;
 use heed::EnvOpenOptions;
 use log::debug;
 use structopt::StructOpt;
@@ -59,18 +61,22 @@ pub fn run(opt: Opt) -> anyhow::Result<()> {
         let query = result?;
         let result = index.search(&rtxn).query(query).execute().unwrap();
 
-        let headers = match index.headers(&rtxn)? {
+        let mut stdout = io::stdout();
-            Some(headers) => headers,
+        let fields_ids_map = index.fields_ids_map(&rtxn)?.unwrap_or_default();
-            None => return Ok(()),
-        };
         let documents = index.documents(&rtxn, result.documents_ids.iter().cloned())?;
 
-        let mut wtr = csv::Writer::from_writer(io::stdout());
-        wtr.write_record(&headers)?;
         for (_id, record) in documents {
-            wtr.write_record(record.iter().map(|(_, v)| v))?;
+            let document: anyhow::Result<HashMap<_, _>> = record.iter()
+                .map(|(k, v)| {
+                    let key = fields_ids_map.name(k).context("field id not found")?;
+                    let val = std::str::from_utf8(v)?;
+                    Ok((key, val))
+                })
+                .collect();
+
+            let document = document?;
+            serde_json::to_writer(&mut stdout, &document)?;
         }
-        wtr.flush()?;
 
         debug!("Took {:.02?} to find {} documents", before.elapsed(), result.documents_ids.len());
     }

src/subcommand/serve.rs

@@ -382,11 +382,12 @@ pub fn run(opt: Opt) -> anyhow::Result<()> {
             let SearchResult { found_words, documents_ids } = search.execute().unwrap();
 
             let mut documents = Vec::new();
-            if let Some(headers) = index.headers(&rtxn).unwrap() {
+            let fields_ids_map = index.fields_ids_map(&rtxn).unwrap().unwrap_or_default();
+
             for (_id, record) in index.documents(&rtxn, documents_ids).unwrap() {
                 let mut record = record.iter()
                     .map(|(key_id, value)| {
-                            let key = headers[key_id as usize].to_owned();
+                        let key = fields_ids_map.name(key_id).unwrap().to_owned();
                         let value = std::str::from_utf8(value).unwrap().to_owned();
                         (key, value)
                     })
@@ -398,7 +399,6 @@ pub fn run(opt: Opt) -> anyhow::Result<()> {
 
                 documents.push(record);
             }
-            }
 
             Response::builder()
                 .header("Content-Type", "application/json")