fix(fulltext-index): single segment is not sufficient for >50M rows S…

…ST (#4552)

* fix(fulltext-index): single segment is not sufficient for a >50M rows SST

Signed-off-by: Zhenchi <zhongzc_arch@outlook.com>

* fix: update doc comment

Signed-off-by: Zhenchi <zhongzc_arch@outlook.com>

---------

Signed-off-by: Zhenchi <zhongzc_arch@outlook.com>

src/index/Cargo.toml

@@ -15,6 +15,7 @@ bytes.workspace = true
 common-base.workspace = true
 common-error.workspace = true
 common-macro.workspace = true
+common-runtime.workspace = true
 common-telemetry.workspace = true
 fst.workspace = true
 futures.workspace = true

src/index/src/fulltext_index/create.rs

@@ -15,7 +15,7 @@
 mod tantivy;
 
 use async_trait::async_trait;
-pub use tantivy::{TantivyFulltextIndexCreator, TEXT_FIELD_NAME};
+pub use tantivy::{TantivyFulltextIndexCreator, ROWID_FIELD_NAME, TEXT_FIELD_NAME};
 
 use crate::fulltext_index::error::Result;
 

src/index/src/fulltext_index/create/tantivy.rs

@@ -16,28 +16,33 @@ use std::path::Path;
 
 use async_trait::async_trait;
 use snafu::{OptionExt, ResultExt};
-use tantivy::schema::{Schema, TEXT};
+use tantivy::indexer::NoMergePolicy;
+use tantivy::schema::{Schema, STORED, TEXT};
 use tantivy::store::{Compressor, ZstdCompressor};
 use tantivy::tokenizer::{LowerCaser, SimpleTokenizer, TextAnalyzer, TokenizerManager};
-use tantivy::{doc, Index, SingleSegmentIndexWriter};
+use tantivy::{doc, Index, IndexWriter};
 use tantivy_jieba::JiebaTokenizer;
 
 use crate::fulltext_index::create::FulltextIndexCreator;
-use crate::fulltext_index::error::{FinishedSnafu, IoSnafu, Result, TantivySnafu};
+use crate::fulltext_index::error::{FinishedSnafu, IoSnafu, JoinSnafu, Result, TantivySnafu};
 use crate::fulltext_index::{Analyzer, Config};
 
 pub const TEXT_FIELD_NAME: &str = "greptime_fulltext_text";
+pub const ROWID_FIELD_NAME: &str = "greptime_fulltext_rowid";
 
 /// `TantivyFulltextIndexCreator` is a fulltext index creator using tantivy.
-///
-/// Here use a single segment to store the index so the maximum capacity for
-/// the index is limited to 2<<31 rows (around 2 billion rows).
 pub struct TantivyFulltextIndexCreator {
     /// The tantivy index writer.
-    writer: Option<SingleSegmentIndexWriter>,
+    writer: Option<IndexWriter>,
 
     /// The field for the text.
     text_field: tantivy::schema::Field,
+
+    /// The field for the row id.
+    rowid_field: tantivy::schema::Field,
+
+    /// The current max row id.
+    max_rowid: u64,
 }
 
 impl TantivyFulltextIndexCreator {
@@ -51,6 +56,7 @@ impl TantivyFulltextIndexCreator {
 
         let mut schema_builder = Schema::builder();
         let text_field = schema_builder.add_text_field(TEXT_FIELD_NAME, TEXT);
+        let rowid_field = schema_builder.add_u64_field(ROWID_FIELD_NAME, STORED);
         let schema = schema_builder.build();
 
         let mut index = Index::create_in_dir(path, schema).context(TantivySnafu)?;
@@ -59,10 +65,17 @@ impl TantivyFulltextIndexCreator {
 
         let memory_limit = Self::sanitize_memory_limit(memory_limit);
 
-        let writer = SingleSegmentIndexWriter::new(index, memory_limit).context(TantivySnafu)?;
+        // Use one thread to keep order of the row id.
+        let writer = index
+            .writer_with_num_threads(1, memory_limit)
+            .context(TantivySnafu)?;
+        writer.set_merge_policy(Box::new(NoMergePolicy));
+
         Ok(Self {
             writer: Some(writer),
             text_field,
+            rowid_field,
+            max_rowid: 0,
         })
     }
 
@@ -86,7 +99,7 @@ impl TantivyFulltextIndexCreator {
         // Port from tantivy::indexer::index_writer::{MEMORY_BUDGET_NUM_BYTES_MIN, MEMORY_BUDGET_NUM_BYTES_MAX}
         const MARGIN_IN_BYTES: usize = 1_000_000;
         const MEMORY_BUDGET_NUM_BYTES_MIN: usize = ((MARGIN_IN_BYTES as u32) * 15u32) as usize;
-        const MEMORY_BUDGET_NUM_BYTES_MAX: usize = u32::MAX as usize - MARGIN_IN_BYTES;
+        const MEMORY_BUDGET_NUM_BYTES_MAX: usize = u32::MAX as usize - MARGIN_IN_BYTES - 1;
 
         memory_limit.clamp(MEMORY_BUDGET_NUM_BYTES_MIN, MEMORY_BUDGET_NUM_BYTES_MAX)
     }
@@ -96,20 +109,25 @@ impl TantivyFulltextIndexCreator {
 impl FulltextIndexCreator for TantivyFulltextIndexCreator {
     async fn push_text(&mut self, text: &str) -> Result<()> {
         let writer = self.writer.as_mut().context(FinishedSnafu)?;
-        let doc = doc!(self.text_field => text);
-        writer.add_document(doc).context(TantivySnafu)
+        let doc = doc!(self.text_field => text, self.rowid_field => self.max_rowid);
+        self.max_rowid += 1;
+        writer.add_document(doc).context(TantivySnafu)?;
+        Ok(())
     }
 
     async fn finish(&mut self) -> Result<()> {
-        let writer = self.writer.take().context(FinishedSnafu)?;
-        writer.finalize().map(|_| ()).context(TantivySnafu)
+        let mut writer = self.writer.take().context(FinishedSnafu)?;
+        common_runtime::spawn_blocking_global(move || {
+            writer.commit().context(TantivySnafu)?;
+            writer.wait_merging_threads().context(TantivySnafu)
+        })
+        .await
+        .context(JoinSnafu)?
     }
 
     fn memory_usage(&self) -> usize {
-        self.writer
-            .as_ref()
-            .map(|writer| writer.mem_usage())
-            .unwrap_or(0)
+        // Unable to get the memory usage of `IndexWriter`.
+        0
     }
 }
 
@@ -118,6 +136,8 @@ mod tests {
     use common_test_util::temp_dir::create_temp_dir;
     use tantivy::collector::DocSetCollector;
     use tantivy::query::QueryParser;
+    use tantivy::schema::Value;
+    use tantivy::TantivyDocument;
 
     use super::*;
 
@@ -235,7 +255,16 @@ mod tests {
             );
             let query = query_parser.parse_query(query).unwrap();
             let docs = searcher.search(&query, &DocSetCollector).unwrap();
-            let mut res = docs.into_iter().map(|d| d.doc_id).collect::<Vec<_>>();
+
+            let mut res = vec![];
+            let rowid_field = searcher.schema().get_field(ROWID_FIELD_NAME).unwrap();
+            for doc_addr in &docs {
+                let doc: TantivyDocument = searcher.doc(*doc_addr).unwrap();
+                let rowid = doc.get_first(rowid_field).unwrap().as_u64().unwrap();
+                assert_eq!(rowid as u32, doc_addr.doc_id);
+                res.push(rowid as u32);
+            }
+
             res.sort();
             assert_eq!(res, *expected);
         }

src/index/src/fulltext_index/error.rs

@@ -19,6 +19,7 @@ use common_error::ext::{BoxedError, ErrorExt};
 use common_error::status_code::StatusCode;
 use common_macro::stack_trace_debug;
 use snafu::{Location, Snafu};
+use tantivy::DocAddress;
 
 #[derive(Snafu)]
 #[snafu(visibility(pub))]
@@ -48,6 +49,13 @@ pub enum Error {
         location: Location,
     },
 
+    #[snafu(display("Tantivy doc not found"))]
+    TantivyDocNotFound {
+        #[snafu(implicit)]
+        location: Location,
+        doc_addr: DocAddress,
+    },
+
     #[snafu(display("Operate on a finished creator"))]
     Finished {
         #[snafu(implicit)]
@@ -60,17 +68,25 @@ pub enum Error {
         #[snafu(implicit)]
         location: Location,
     },
+
+    #[snafu(display("Join error"))]
+    Join {
+        #[snafu(source)]
+        error: tokio::task::JoinError,
+        #[snafu(implicit)]
+        location: Location,
+    },
 }
 
 impl ErrorExt for Error {
     fn status_code(&self) -> StatusCode {
         use Error::*;
 
         match self {
-            Tantivy { .. } => StatusCode::Internal,
+            Tantivy { .. } | TantivyDocNotFound { .. } => StatusCode::Internal,
             TantivyParser { .. } => StatusCode::InvalidSyntax,
 
-            Io { .. } | Finished { .. } => StatusCode::Unexpected,
+            Io { .. } | Finished { .. } | Join { .. } => StatusCode::Unexpected,
 
             External { source, .. } => source.status_code(),
         }

src/index/src/fulltext_index/search/tantivy.rs

@@ -12,20 +12,22 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::collections::BTreeSet;
+use std::collections::{BTreeSet, HashMap};
 use std::path::Path;
 use std::time::Instant;
 
 use async_trait::async_trait;
 use common_telemetry::debug;
-use snafu::ResultExt;
+use snafu::{OptionExt, ResultExt};
 use tantivy::collector::DocSetCollector;
 use tantivy::query::QueryParser;
-use tantivy::schema::Field;
-use tantivy::{Index, IndexReader, ReloadPolicy};
+use tantivy::schema::{Field, Value};
+use tantivy::{Index, IndexReader, ReloadPolicy, TantivyDocument};
 
-use crate::fulltext_index::create::TEXT_FIELD_NAME;
-use crate::fulltext_index::error::{Result, TantivyParserSnafu, TantivySnafu};
+use crate::fulltext_index::create::{ROWID_FIELD_NAME, TEXT_FIELD_NAME};
+use crate::fulltext_index::error::{
+    Result, TantivyDocNotFoundSnafu, TantivyParserSnafu, TantivySnafu,
+};
 use crate::fulltext_index::search::{FulltextIndexSearcher, RowId};
 
 /// `TantivyFulltextIndexSearcher` is a searcher using Tantivy.
@@ -77,9 +79,48 @@ impl FulltextIndexSearcher for TantivyFulltextIndexSearcher {
         let query = query_parser
             .parse_query(query)
             .context(TantivyParserSnafu)?;
-        let docs = searcher
+        let doc_addrs = searcher
             .search(&query, &DocSetCollector)
             .context(TantivySnafu)?;
-        Ok(docs.into_iter().map(|d| d.doc_id).collect())
+
+        let seg_metas = self
+            .index
+            .searchable_segment_metas()
+            .context(TantivySnafu)?;
+
+        // FAST PATH: only one segment, the doc id is the same as the row id.
+        //            Also for compatibility with the old version.
+        if seg_metas.len() == 1 {
+            return Ok(doc_addrs.into_iter().map(|d| d.doc_id).collect());
+        }
+
+        // SLOW PATH: multiple segments, need to calculate the row id.
+        let rowid_field = searcher
+            .schema()
+            .get_field(ROWID_FIELD_NAME)
+            .context(TantivySnafu)?;
+        let mut seg_offsets = HashMap::with_capacity(seg_metas.len());
+        let mut res = BTreeSet::new();
+        for doc_addr in doc_addrs {
+            let offset = if let Some(offset) = seg_offsets.get(&doc_addr.segment_ord) {
+                *offset
+            } else {
+                // Calculate the offset at the first time meeting the segment and cache it since
+                // the offset is the same for all rows in the same segment.
+                let doc: TantivyDocument = searcher.doc(doc_addr).context(TantivySnafu)?;
+                let rowid = doc
+                    .get_first(rowid_field)
+                    .and_then(|v| v.as_u64())
+                    .context(TantivyDocNotFoundSnafu { doc_addr })?;
+
+                let offset = rowid as u32 - doc_addr.doc_id;
+                seg_offsets.insert(doc_addr.segment_ord, offset);
+                offset
+            };
+
+            res.insert(doc_addr.doc_id + offset);
+        }
+
+        Ok(res)
     }
 }