feat: allow the index_cache_size to be configured when opening a table (#1245)

This was already configurable in the rust API but it wasn't actually
being passed down to the underlying dataset. I added this option to both
the async python API and the new nodejs API.

I also added this option to the synchronous python API.

I did not add the option to vectordb.

nodejs/lancedb/connection.ts

@@ -77,6 +77,18 @@ export interface OpenTableOptions {
    * The available options are described at https://lancedb.github.io/lancedb/guides/storage/
    */
   storageOptions?: Record<string, string>;
+  /**
+   * Set the size of the index cache, specified as a number of entries
+   *
+   * The exact meaning of an "entry" will depend on the type of index:
+   * - IVF: there is one entry for each IVF partition
+   * - BTREE: there is one entry for the entire index
+   *
+   * This cache applies to the entire opened table, across all indices.
+   * Setting this value higher will increase performance on larger datasets
+   * at the expense of more RAM
+   */
+  indexCacheSize?: number;
 }
 
 export interface TableNamesOptions {
@@ -160,6 +172,7 @@ export class Connection {
     const innerTable = await this.inner.openTable(
       name,
       cleanseStorageOptions(options?.storageOptions),
+      options?.indexCacheSize,
     );
     return new Table(innerTable);
   }

nodejs/src/connection.rs

@@ -176,6 +176,7 @@ impl Connection {
         &self,
         name: String,
         storage_options: Option<HashMap<String, String>>,
+        index_cache_size: Option<u32>,
     ) -> napi::Result<Table> {
         let mut builder = self.get_inner()?.open_table(&name);
         if let Some(storage_options) = storage_options {
@@ -183,6 +184,9 @@ impl Connection {
                 builder = builder.storage_option(key, value);
             }
         }
+        if let Some(index_cache_size) = index_cache_size {
+            builder = builder.index_cache_size(index_cache_size);
+        }
         let tbl = builder
             .execute()
             .await