Add option sqlite_debug_show_queries to print queries sent to SQLite

.gitignore

@@ -5,4 +5,5 @@ cmake-build-debug
 sqlite/build
 tpch.db
 .clang-format
-*.tbl
+*.tbl
+duckdb_unittest_tempdir/

src/include/sqlite_db.hpp

@@ -49,6 +49,8 @@ class SQLiteDB {
 	bool ColumnExists(const string &table_name, const string &column_name);
 	vector<IndexInfo> GetIndexInfo(const string &table_name);
 
+	static void DebugSetPrintQueries(bool print);
+
 	bool IsOpen();
 	void Close();
 };

src/sqlite_db.cpp

@@ -9,6 +9,8 @@
 
 namespace duckdb {
 
+static bool debug_sqlite_print_queries = false;
+
 SQLiteDB::SQLiteDB() : db(nullptr) {
 }
 
@@ -64,6 +66,9 @@ SQLiteDB SQLiteDB::Open(const string &path, const SQLiteOpenOptions &options, bo
 
 bool SQLiteDB::TryPrepare(const string &query, SQLiteStatement &stmt) {
 	stmt.db = db;
+	if (debug_sqlite_print_queries) {
+		Printer::Print(query + "\n");
+	}
 	auto rc = sqlite3_prepare_v2(db, query.c_str(), -1, &stmt.stmt, nullptr);
 	if (rc != SQLITE_OK) {
 		return false;
@@ -81,6 +86,9 @@ SQLiteStatement SQLiteDB::Prepare(const string &query) {
 }
 
 void SQLiteDB::Execute(const string &query) {
+	if (debug_sqlite_print_queries) {
+		Printer::Print(query + "\n");
+	}
 	auto rc = sqlite3_exec(db, query.c_str(), nullptr, nullptr, nullptr);
 	if (rc != SQLITE_OK) {
 		string error = "Failed to execute query \"" + query + "\": " + string(sqlite3_errmsg(db));
@@ -303,4 +311,8 @@ idx_t SQLiteDB::RunPragma(string pragma_name) {
 	throw InternalException("No result returned from pragma " + pragma_name);
 }
 
+void SQLiteDB::DebugSetPrintQueries(bool print) {
+	debug_sqlite_print_queries = print;
+}
+
 } // namespace duckdb

src/sqlite_extension.cpp

@@ -3,6 +3,7 @@
 #endif
 #include "duckdb.hpp"
 
+#include "sqlite_db.hpp"
 #include "sqlite_scanner.hpp"
 #include "sqlite_storage.hpp"
 #include "sqlite_scanner_extension.hpp"
@@ -15,6 +16,10 @@ using namespace duckdb;
 
 extern "C" {
 
+static void SetSqliteDebugQueryPrint(ClientContext &context, SetScope scope, Value &parameter) {
+	SQLiteDB::DebugSetPrintQueries(BooleanValue::Get(parameter));
+}
+
 static void LoadInternal(DatabaseInstance &db) {
 	SqliteScanFunction sqlite_fun;
 	ExtensionUtil::RegisterFunction(db, sqlite_fun);
@@ -25,6 +30,9 @@ static void LoadInternal(DatabaseInstance &db) {
 	auto &config = DBConfig::GetConfig(db);
 	config.AddExtensionOption("sqlite_all_varchar", "Load all SQLite columns as VARCHAR columns", LogicalType::BOOLEAN);
 
+	config.AddExtensionOption("sqlite_debug_show_queries", "DEBUG SETTING: print all queries sent to SQLite to stdout",
+	                          LogicalType::BOOLEAN, Value::BOOLEAN(false), SetSqliteDebugQueryPrint);
+
 	config.storage_extensions["sqlite_scanner"] = make_uniq<SQLiteStorageExtension>();
 }
 

test/sql/storage/attach_debug_print_unharmful.test

@@ -0,0 +1,40 @@
+# name: test/sql/storage/attach_debug_print_unharmful.test
+# description: set sqlite_debug_show_queries setting to true, make sure a sample query still runs properly
+# group: [sqlite_storage]
+
+require sqlite_scanner
+
+statement ok
+CALL sqlite_attach('data/db/sakila.db');
+
+query IIII
+SELECT * FROM actor LIMIT 10;
+----
+1	PENELOPE	GUINESS	2021-03-06 15:51:59
+2	NICK	WAHLBERG	2021-03-06 15:51:59
+3	ED	CHASE	2021-03-06 15:51:59
+4	JENNIFER	DAVIS	2021-03-06 15:51:59
+5	JOHNNY	LOLLOBRIGIDA	2021-03-06 15:51:59
+6	BETTE	NICHOLSON	2021-03-06 15:51:59
+7	GRACE	MOSTEL	2021-03-06 15:51:59
+8	MATTHEW	JOHANSSON	2021-03-06 15:51:59
+9	JOE	SWANK	2021-03-06 15:51:59
+10	CHRISTIAN	GABLE	2021-03-06 15:51:59
+
+
+statement ok
+SET sqlite_debug_show_queries=true;
+
+query IIII
+SELECT * FROM actor LIMIT 10;
+----
+1	PENELOPE	GUINESS	2021-03-06 15:51:59
+2	NICK	WAHLBERG	2021-03-06 15:51:59
+3	ED	CHASE	2021-03-06 15:51:59
+4	JENNIFER	DAVIS	2021-03-06 15:51:59
+5	JOHNNY	LOLLOBRIGIDA	2021-03-06 15:51:59
+6	BETTE	NICHOLSON	2021-03-06 15:51:59
+7	GRACE	MOSTEL	2021-03-06 15:51:59
+8	MATTHEW	JOHANSSON	2021-03-06 15:51:59
+9	JOE	SWANK	2021-03-06 15:51:59
+10	CHRISTIAN	GABLE	2021-03-06 15:51:59