Merge pull request #34 from Mytherin/norowid

Allow scanning of tables without a row id, and report correct error code when calling sqlite_attach on a non-existent database

Author: Mytherin

data/norowid.db

@@ -29,6 +29,7 @@ class SQLiteDB {
 
 public:
 	static SQLiteDB Open(const string &path, bool is_read_only = true, bool is_shared = false);
+	bool TryPrepare(const string &query, SQLiteStatement &result);
 	SQLiteStatement Prepare(const string &query);
 	void Execute(const string &query);
 	vector<string> GetTables();
@@ -40,7 +41,8 @@ class SQLiteDB {
 	void GetViewInfo(const string &view_name, string &sql);
 	void GetIndexInfo(const string &index_name, string &sql, string &table_name);
 	idx_t RunPragma(string pragma_name);
-	idx_t GetMaxRowId(const string &table_name);
+	//! Gets the max row id of a table, returns false if the table does not have a rowid column
+	bool GetMaxRowId(const string &table_name, idx_t &row_id);
 	bool ColumnExists(const string &table_name, const string &column_name);
 
 	bool IsOpen();

src/include/sqlite_db.hpp

@@ -39,15 +39,26 @@ SQLiteDB SQLiteDB::Open(const string &path, bool is_read_only, bool is_shared) {
 		// FIXME: we should just make sure we are not re-using the same `sqlite3` object across threads
 		flags |= SQLITE_OPEN_NOMUTEX;
 	}
-	SQLiteUtils::Check(sqlite3_open_v2(path.c_str(), &result.db, flags, nullptr), result.db);
+	flags |= SQLITE_OPEN_EXRESCODE;
+	auto rc = sqlite3_open_v2(path.c_str(), &result.db, flags, nullptr);
+	if (rc != SQLITE_OK) {
+		throw std::runtime_error("Unable to open database \"" + path + "\": " + string(sqlite3_errstr(rc)));
+	}
 	return result;
 }
 
-SQLiteStatement SQLiteDB::Prepare(const string &query) {
-	SQLiteStatement stmt;
+bool SQLiteDB::TryPrepare(const string &query, SQLiteStatement &stmt) {
 	stmt.db = db;
 	auto rc = sqlite3_prepare_v2(db, query.c_str(), -1, &stmt.stmt, nullptr);
 	if (rc != SQLITE_OK) {
+		return false;
+	}
+	return true;
+}
+
+SQLiteStatement SQLiteDB::Prepare(const string &query) {
+	SQLiteStatement stmt;
+	if (!TryPrepare(query, stmt)) {
 		string error = "Failed to prepare query \"" + query + "\": " + string(sqlite3_errmsg(db));
 		throw std::runtime_error(error);
 	}
@@ -196,13 +207,17 @@ bool SQLiteDB::ColumnExists(const string &table_name, const string &column_name)
 	return false;
 }
 
-idx_t SQLiteDB::GetMaxRowId(const string &table_name) {
+bool SQLiteDB::GetMaxRowId(const string &table_name, idx_t &max_row_id) {
 	SQLiteStatement stmt;
-	stmt = Prepare(StringUtil::Format("SELECT MAX(ROWID) FROM \"%s\"", SQLiteUtils::SanitizeIdentifier(table_name)));
+	if (!TryPrepare(StringUtil::Format("SELECT MAX(ROWID) FROM \"%s\"", SQLiteUtils::SanitizeIdentifier(table_name)),
+	                stmt)) {
+		return false;
+	}
 	if (!stmt.Step()) {
-		throw std::runtime_error("could not find max rowid?");
+		return false;
 	}
-	return stmt.GetValue<int64_t>(0);
+	max_row_id = stmt.GetValue<int64_t>(0);
+	return true;
 }
 
 idx_t SQLiteDB::RunPragma(string pragma_name) {

src/sqlite_db.cpp

@@ -70,7 +70,10 @@ static unique_ptr<FunctionData> SqliteBind(ClientContext &context, TableFunction
 		throw std::runtime_error("no columns for table " + result->table_name);
 	}
 
-	result->max_rowid = db.GetMaxRowId(result->table_name);
+	if (!db.GetMaxRowId(result->table_name, result->max_rowid)) {
+		result->max_rowid = idx_t(-1);
+		result->rows_per_group = idx_t(-1);
+	}
 
 	result->names = names;
 	result->types = return_types;

src/sqlite_scanner.cpp

@@ -28,7 +28,10 @@ TableFunction SQLiteTableEntry::GetScanFunction(ClientContext &context, unique_p
 	auto &transaction = (SQLiteTransaction &)Transaction::Get(context, *catalog);
 	auto &db = transaction.GetDB();
 
-	result->max_rowid = db.GetMaxRowId(name);
+	if (!db.GetMaxRowId(name, result->max_rowid)) {
+		result->max_rowid = idx_t(-1);
+		result->rows_per_group = idx_t(-1);
+	}
 	if (!transaction.IsReadOnly() || sqlite_catalog->InMemory()) {
 		// for in-memory databases or if we have transaction-local changes we can only do a single-threaded scan
 		// set up the transaction's connection object as the global db
@@ -44,7 +47,10 @@ TableStorageInfo SQLiteTableEntry::GetStorageInfo(ClientContext &context) {
 	auto &transaction = (SQLiteTransaction &)Transaction::Get(context, *catalog);
 	auto &db = transaction.GetDB();
 	TableStorageInfo result;
-	result.cardinality = db.GetMaxRowId(name);
+	if (!db.GetMaxRowId(name, result.cardinality)) {
+		// probably
+		result.cardinality = 10000;
+	}
 	return result;
 }
 

src/storage/sqlite_table_entry.cpp

@@ -0,0 +1,16 @@
+statement ok
+LOAD 'build/release/extension/sqlite_scanner/sqlite_scanner.duckdb_extension';
+
+statement ok
+ATTACH 'data/norowid.db' AS s (TYPE SQLITE, READ_ONLY)
+
+query II
+SELECT * FROM s.wordcount
+----
+hello	10
+world	5
+
+query II
+SELECT * FROM s.wordcount WHERE word='world'
+----
+world	5