feat: add the ability to create scalar indices (#679)

This is a pretty direct binding to the underlying lance capability

rust/ffi/node/src/index.rs

@@ -12,4 +12,5 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+pub mod scalar;
 pub mod vector;

rust/ffi/node/src/index/scalar.rs

@@ -0,0 +1,43 @@
+// Copyright 2023 Lance Developers.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use neon::{
+    context::{Context, FunctionContext},
+    result::JsResult,
+    types::{JsBoolean, JsBox, JsPromise, JsString},
+};
+
+use crate::{error::ResultExt, runtime, table::JsTable};
+
+pub(crate) fn table_create_scalar_index(mut cx: FunctionContext) -> JsResult<JsPromise> {
+    let js_table = cx.this().downcast_or_throw::<JsBox<JsTable>, _>(&mut cx)?;
+    let column = cx.argument::<JsString>(0)?.value(&mut cx);
+    let replace = cx.argument::<JsBoolean>(1)?.value(&mut cx);
+
+    let rt = runtime(&mut cx)?;
+
+    let (deferred, promise) = cx.promise();
+    let channel = cx.channel();
+    let mut table = js_table.table.clone();
+
+    rt.spawn(async move {
+        let idx_result = table.create_scalar_index(&column, replace).await;
+
+        deferred.settle_with(&channel, move |mut cx| {
+            idx_result.or_throw(&mut cx)?;
+            Ok(cx.undefined())
+        });
+    });
+    Ok(promise)
+}

rust/ffi/node/src/lib.rs

@@ -242,6 +242,10 @@ fn main(mut cx: ModuleContext) -> NeonResult<()> {
     cx.export_function("tableCompactFiles", JsTable::js_compact)?;
     cx.export_function("tableListIndices", JsTable::js_list_indices)?;
     cx.export_function("tableIndexStats", JsTable::js_index_stats)?;
+    cx.export_function(
+        "tableCreateScalarIndex",
+        index::scalar::table_create_scalar_index,
+    )?;
     cx.export_function(
         "tableCreateVectorIndex",
         index::vector::table_create_vector_index,

rust/vectordb/src/table.rs

@@ -14,6 +14,7 @@
 
 use chrono::Duration;
 use lance::dataset::builder::DatasetBuilder;
+use lance::index::scalar::ScalarIndexParams;
 use lance_index::IndexType;
 use std::sync::Arc;
 
@@ -262,6 +263,16 @@ impl Table {
         Ok(())
     }
 
+    /// Create a scalar index on the table
+    pub async fn create_scalar_index(&mut self, column: &str, replace: bool) -> Result<()> {
+        let mut dataset = self.dataset.as_ref().clone();
+        let params = ScalarIndexParams::default();
+        dataset
+            .create_index(&[column], IndexType::Scalar, None, &params, replace)
+            .await?;
+        Ok(())
+    }
+
     pub async fn optimize_indices(&mut self) -> Result<()> {
         let mut dataset = self.dataset.as_ref().clone();