Put the documents MTBL back into LMDB

We makes sure to write the documents into a file before
memory mapping it and putting it into LMDB, this way we avoid
moving it to RAM

src/bin/serve.rs

@@ -62,7 +62,6 @@ fn highlight_string(string: &str, words: &HashSet<String>) -> String {
 struct IndexTemplate {
     db_name: String,
     db_size: usize,
-    docs_size: usize,
     docs_count: usize,
 }
 
@@ -83,28 +82,23 @@ async fn main() -> anyhow::Result<()> {
         .open(&opt.database)?;
 
     // Open the LMDB database.
-    let index = Index::new(&env, &opt.database)?;
+    let index = Index::new(&env)?;
 
     // Retrieve the database the file stem (w/o the extension),
     // the disk file size and the number of documents in the database.
     let db_name = opt.database.file_stem().and_then(|s| s.to_str()).unwrap_or("").to_string();
     let db_size = File::open(opt.database.join("data.mdb"))?.metadata()?.len() as usize;
-    let docs_size = File::open(opt.database.join("documents.mtbl"))?.metadata()?.len() as usize;
-    let docs_count = index.number_of_documents();
+
+    let rtxn = env.read_txn()?;
+    let docs_count = index.number_of_documents(&rtxn)? as usize;
+    drop(rtxn);
 
     // We run and wait on the HTTP server
 
     // Expose an HTML page to debug the search in a browser
     let dash_html_route = warp::filters::method::get()
         .and(warp::filters::path::end())
-        .map(move || {
-            IndexTemplate {
-                db_name: db_name.clone(),
-                db_size,
-                docs_size,
-                docs_count: docs_count as usize,
-            }
-        });
+        .map(move || IndexTemplate { db_name: db_name.clone(), db_size, docs_count });
 
     let dash_bulma_route = warp::filters::method::get()
         .and(warp::path!("bulma.min.css"))
@@ -192,7 +186,7 @@ async fn main() -> anyhow::Result<()> {
             if let Some(headers) = index.headers(&rtxn).unwrap() {
                 // We write the headers
                 body.extend_from_slice(headers);
-                let documents = index.documents(documents_ids).unwrap();
+                let documents = index.documents(&rtxn, documents_ids).unwrap();
 
                 for (_id, content) in documents {
                     let content = std::str::from_utf8(content.as_ref()).unwrap();