From 54ed2c3c0aa9ea1c8df7a7feb0d36d9d86849bac Mon Sep 17 00:00:00 2001
From: rustmailer <pollybase@zohomail.com>
Date: Fri, 6 Mar 2026 22:54:38 +0800
Subject: [PATCH] chore: optimize CPU usage #159

---
 src/modules/indexer/manager.rs | 37 ++++++++++++++++++++++------------
 src/modules/settings/cli.rs    | 21 ++++++++++++++++++-
 2 files changed, 44 insertions(+), 14 deletions(-)

diff --git a/src/modules/indexer/manager.rs b/src/modules/indexer/manager.rs
index 0af7476..462fa0c 100644
--- a/src/modules/indexer/manager.rs
+++ b/src/modules/indexer/manager.rs
@@ -44,7 +44,7 @@ use crate::{
 
 use mail_parser::{MessageParser, MimeHeaders};
 
-use tantivy::indexer::UserOperation;
+use tantivy::indexer::{LogMergePolicy, UserOperation};
 use tantivy::{
     collector::TopDocs,
     query::{BooleanQuery, Occur, Query, TermQuery},
@@ -339,19 +339,30 @@ pub struct EmlIndexManager {
 impl EmlIndexManager {
     pub fn new() -> Self {
         let index = Self::open_or_create_index(&DATA_DIR_MANAGER.eml_dir);
-        let index_writer = Arc::new(Mutex::new(
-            index
-                .writer_with_num_threads(
+
+        let writer: IndexWriter<TantivyDocument> = index
+            .writer_with_num_threads(
+                SETTINGS.bichon_tantivy_threads as usize,
+                SETTINGS.bichon_tantivy_buffer_size,
+            )
+            .unwrap_or_else(|e| {
+                panic!(
+                    "Failed to create IndexWriter (threads: {}, buffer: {}B) for {:?}: {}",
                     SETTINGS.bichon_tantivy_threads,
                     SETTINGS.bichon_tantivy_buffer_size,
+                    DATA_DIR_MANAGER.eml_dir,
+                    e
                 )
-                .unwrap_or_else(|e| {
-                    panic!(
-                        "Failed to create IndexWriter with 8 threads and 128MB buffer for {:?}: {}",
-                        DATA_DIR_MANAGER.eml_dir, e
-                    )
-                }),
-        ));
+            });
+
+        let mut merge_policy = LogMergePolicy::default();
+        merge_policy.set_min_num_segments(20);
+        merge_policy.set_max_docs_before_merge(10_000);
+        merge_policy.set_min_layer_size(1000);
+        writer.set_merge_policy(Box::new(merge_policy));
+
+        let index_writer = Arc::new(Mutex::new(writer));
+
         let reader = index.reader().unwrap_or_else(|e| {
             panic!(
                 "Failed to create IndexReader for {:?}: {}",
@@ -433,10 +444,10 @@ impl EmlIndexManager {
                 .schema(SchemaTools::eml_schema())
                 .settings(IndexSettings {
                     docstore_compression: Compressor::Zstd(ZstdCompressor {
-                        compression_level: Some(6),
+                        compression_level: Some(SETTINGS.bichon_eml_compression_level as i32),
                     }),
                     docstore_compress_dedicated_thread: true,
-                    docstore_blocksize: 2_097_152,
+                    docstore_blocksize: SETTINGS.bichon_eml_blocksize,
                 })
                 .create_in_dir(&index_dir)
                 .unwrap_or_else(|e| panic!("Failed to create index in {:?}: {}", index_dir, e))
diff --git a/src/modules/settings/cli.rs b/src/modules/settings/cli.rs
index 5ec164f..77522ea 100644
--- a/src/modules/settings/cli.rs
+++ b/src/modules/settings/cli.rs
@@ -271,7 +271,7 @@ pub struct Settings {
         help = "Number of Tantivy execution threads (default: 4)",
         value_parser = clap::value_parser!(u16).range(1..)
     )]
-    pub bichon_tantivy_threads: usize,
+    pub bichon_tantivy_threads: u16,
 
     /// Tantivy indexer memory budget in bytes (default: 256MB)
     #[clap(
@@ -281,6 +281,25 @@ pub struct Settings {
         help = "Set the memory budget for Tantivy indexer in bytes (default: 256MB)"
     )]
     pub bichon_tantivy_buffer_size: usize,
+
+    /// Zstd compression level for EML storage (default: 3)
+    #[clap(
+        long,
+        env,
+        default_value = "3",
+        help = "Set the Zstd compression level for EML storage (1-22)",
+        value_parser = clap::value_parser!(u16).range(1..22)
+    )]
+    pub bichon_eml_compression_level: u16,
+
+    /// Tantivy docstore block size in bytes (default: 1MB)
+    #[clap(
+        long,
+        env,
+        default_value = "2097152",
+        help = "Set the Tantivy docstore block size in bytes (default: 2MB)"
+    )]
+    pub bichon_eml_blocksize: usize,
 }
 
 impl Settings {