Data Explorer: Always read fresh file contents when ingesting a file …

…into duckdb (#5890)

Addresses #5860. duckdb-wasm has some kind of file caching behavior that
is not resilient to file changes on the underlying file system. This
patch nukes this issue from orbit by always registering the file
contents as a virtual file and reading from that. I think if and when we
migrate to the duckdb NodeJS bindings per #5889 that we can avoid this
chicanery. This does the same thing for Parquet files, too, since they would also
become stale. 

e2e: @:data-explorer

### QA Notes

Here was the reproducible failure from the issue:

* Run iris  |> readr::write_csv("test.csv")
* Click on the file in the File Explorer to open it up; note that we
correctly see the iris data
* Run mtcars  |> readr::write_csv("test.csv")
* Again click on the file in the File Explorer to open it up; note that
we incorrectly still see the iris data

extensions/positron-duckdb/src/extension.ts

@@ -1221,7 +1221,7 @@ export class DataExplorerRpcHandler {
 				fs.watchFile(filePath, { interval: 1000 }, async () => {
 					const newTableName = `positron_${this._tableIndex++}`;
 
-					await this.createTableFromFilePath(filePath, newTableName, true);
+					await this.createTableFromFilePath(filePath, newTableName);
 
 					const newSchema = (await this.db.runQuery(`DESCRIBE ${newTableName};`)).toArray();
 					await tableView.onFileUpdated(newTableName, newSchema);
@@ -1241,11 +1241,8 @@ export class DataExplorerRpcHandler {
 	 * Import data file into DuckDB by creating table or view
 	 * @param filePath The file path on disk.
 	 * @param catalogName The table name to use in the DuckDB catalog.
-	 * @param forceRefresh If true, force an uncached read from disk to circumvent DuckDB's
-	 * file handle caching.
 	 */
-	async createTableFromFilePath(filePath: string, catalogName: string,
-		forceRefresh: boolean = false) {
+	async createTableFromFilePath(filePath: string, catalogName: string) {
 
 		const getCsvImportQuery = (_filePath: string, options: Array<String>) => {
 			return `CREATE OR REPLACE TABLE ${catalogName} AS
@@ -1278,24 +1275,22 @@ export class DataExplorerRpcHandler {
 
 		const fileExt = path.extname(filePath);
 
-		if (fileExt === '.parquet' || fileExt === '.parq') {
-			// Always create a view for Parquet files
-			const query = `CREATE VIEW ${catalogName} AS
-			SELECT * FROM parquet_scan('${filePath}');`;
-			await this.db.runQuery(query);
-		} else if (forceRefresh) {
-			// For smaller text files, read the entire contents and register it as a temp file
-			// to avoid caching in duckdb-wasm
-			const fileContents = fs.readFileSync(filePath, { encoding: null });
-			const virtualPath = path.basename(filePath);
-			await this.db.db.registerFileBuffer(virtualPath, fileContents);
-			try {
+		// Read the entire contents and register it as a temp file
+		// to avoid file handle caching in duckdb-wasm
+		const fileContents = fs.readFileSync(filePath, { encoding: null });
+		const virtualPath = path.basename(filePath);
+		await this.db.db.registerFileBuffer(virtualPath, fileContents);
+		try {
+			if (fileExt === '.parquet' || fileExt === '.parq') {
+				// Always create a view for Parquet files
+				const query = `CREATE OR REPLACE TABLE ${catalogName} AS
+				SELECT * FROM parquet_scan('${virtualPath}');`;
+				await this.db.runQuery(query);
+			} else {
 				await importDelimited(virtualPath);
-			} finally {
-				await this.db.db.dropFile(virtualPath);
 			}
-		} else {
-			await importDelimited(filePath);
+		} finally {
+			await this.db.db.dropFile(virtualPath);
 		}
 	}