diff --git a/catalog/internal_tables.go b/catalog/internal_tables.go
index ff424ba..0f3d80d 100644
--- a/catalog/internal_tables.go
+++ b/catalog/internal_tables.go
@@ -12,6 +12,9 @@ type InternalTable struct {
 }
 
 func (it *InternalTable) QualifiedName() string {
+	//if it.Schema == "__sys__" {
+	//	return it.Name
+	//}
 	return it.Schema + "." + it.Name
 }
 
@@ -58,9 +61,7 @@ func (it *InternalTable) UpsertStmt() string {
 	var b strings.Builder
 	b.Grow(128)
 	b.WriteString("INSERT OR REPLACE INTO ")
-	b.WriteString(it.Schema)
-	b.WriteByte('.')
-	b.WriteString(it.Name)
+	b.WriteString(it.QualifiedName())
 	b.WriteString(" VALUES (?")
 	for range it.KeyColumns[1:] {
 		b.WriteString(", ?")
@@ -76,9 +77,7 @@ func (it *InternalTable) DeleteStmt() string {
 	var b strings.Builder
 	b.Grow(128)
 	b.WriteString("DELETE FROM ")
-	b.WriteString(it.Schema)
-	b.WriteByte('.')
-	b.WriteString(it.Name)
+	b.WriteString(it.QualifiedName())
 	b.WriteString(" WHERE ")
 	b.WriteString(it.KeyColumns[0])
 	b.WriteString(" = ?")
@@ -93,9 +92,7 @@ func (it *InternalTable) DeleteAllStmt() string {
 	var b strings.Builder
 	b.Grow(128)
 	b.WriteString("DELETE FROM ")
-	b.WriteString(it.Schema)
-	b.WriteByte('.')
-	b.WriteString(it.Name)
+	b.WriteString(it.QualifiedName())
 	return b.String()
 }
 
@@ -109,9 +106,7 @@ func (it *InternalTable) SelectStmt() string {
 		b.WriteString(c)
 	}
 	b.WriteString(" FROM ")
-	b.WriteString(it.Schema)
-	b.WriteByte('.')
-	b.WriteString(it.Name)
+	b.WriteString(it.QualifiedName())
 	b.WriteString(" WHERE ")
 	b.WriteString(it.KeyColumns[0])
 	b.WriteString(" = ?")
@@ -133,9 +128,7 @@ func (it *InternalTable) SelectColumnsStmt(valueColumns []string) string {
 		b.WriteString(c)
 	}
 	b.WriteString(" FROM ")
-	b.WriteString(it.Schema)
-	b.WriteByte('.')
-	b.WriteString(it.Name)
+	b.WriteString(it.QualifiedName())
 	b.WriteString(" WHERE ")
 	b.WriteString(it.KeyColumns[0])
 	b.WriteString(" = ?")
@@ -151,9 +144,7 @@ func (it *InternalTable) SelectAllStmt() string {
 	var b strings.Builder
 	b.Grow(128)
 	b.WriteString("SELECT * FROM ")
-	b.WriteString(it.Schema)
-	b.WriteByte('.')
-	b.WriteString(it.Name)
+	b.WriteString(it.QualifiedName())
 	return b.String()
 }
 
@@ -162,9 +153,7 @@ func (it *InternalTable) CountAllStmt() string {
 	b.Grow(128)
 	b.WriteString("SELECT COUNT(*)")
 	b.WriteString(" FROM ")
-	b.WriteString(it.Schema)
-	b.WriteByte('.')
-	b.WriteString(it.Name)
+	b.WriteString(it.QualifiedName())
 	return b.String()
 }
 
diff --git a/catalog/provider.go b/catalog/provider.go
index f7dae92..c3ed9b3 100644
--- a/catalog/provider.go
+++ b/catalog/provider.go
@@ -94,7 +94,9 @@ func (prov *DatabaseProvider) DropCatalog(dataDir, dbFile string) error {
 func (prov *DatabaseProvider) CreateCatalog(dataDir, dbFile string) (bool, error) {
 	dbFile = strings.TrimSpace(dbFile)
 	dsn := ""
-	if dbFile != "" {
+	if dbFile == "" || dbFile == "memory.db" {
+		dsn = "memory"
+	} else {
 		dsn = filepath.Join(dataDir, dbFile)
 		// if already exists, return error
 		_, err := os.Stat(dsn)
@@ -168,6 +170,7 @@ func (prov *DatabaseProvider) SwitchCatalog(dataDir, dbFile string) error {
 	if dbFile == "" || dbFile == "memory.db" {
 		// in-memory mode, mainly for testing
 		name = "memory"
+		dsn = "memory"
 	} else {
 		name = strings.Split(dbFile, ".")[0]
 		dsn = filepath.Join(dataDir, dbFile)
diff --git a/harness/duck_harness.go b/harness/duck_harness.go
index 9d32443..4f9530d 100644
--- a/harness/duck_harness.go
+++ b/harness/duck_harness.go
@@ -297,13 +297,12 @@ func (e *DuckTestEngine) Close() error {
 func NewEngine(t *testing.T, harness enginetest.Harness, dbProvider sql.DatabaseProvider, setupData []setup.SetupScript, statsProvider sql.StatsProvider, server bool) (enginetest.QueryEngine, error) {
 	// Create the connection pool first, as it is needed by `NewEngineWithProvider`
 	provider := dbProvider.(*catalog.DatabaseProvider)
-	pool := catalog.NewConnectionPool(provider.CatalogName(), provider.Connector(), provider.Storage())
-	harness.(*DuckHarness).pool = pool
+	harness.(*DuckHarness).pool = provider.Pool()
 
 	e := enginetest.NewEngineWithProvider(t, harness, dbProvider)
 	e.Analyzer.Catalog.StatsProvider = statsProvider
 
-	builder := backend.NewDuckBuilder(e.Analyzer.ExecBuilder, pool, provider)
+	builder := backend.NewDuckBuilder(e.Analyzer.ExecBuilder, provider)
 	e.Analyzer.ExecBuilder = builder
 
 	ctx := enginetest.NewContext(harness)
@@ -329,7 +328,7 @@ func NewEngine(t *testing.T, harness enginetest.Harness, dbProvider sql.Database
 			return nil, err
 		}
 	}
-	return &DuckTestEngine{qe, pool}, nil
+	return &DuckTestEngine{qe, provider.Pool()}, nil
 }
 
 func (m *DuckHarness) SupportsNativeIndexCreation() bool {
diff --git a/pgserver/duck_handler.go b/pgserver/duck_handler.go
index e7909d8..ebfed80 100644
--- a/pgserver/duck_handler.go
+++ b/pgserver/duck_handler.go
@@ -479,7 +479,7 @@ func (h *DuckHandler) executeQuery(ctx *sql.Context, query string, parsed tree.S
 		schema = types.OkResultSchema
 		iter = sql.RowsToRowIter(sql.NewRow(types.OkResult{}))
 	default:
-		rows, err = adapter.QueryCatalog(ctx, ConvertToSys(query))
+		rows, err = adapter.QueryCatalog(ctx, query)
 		if err != nil {
 			break
 		}
diff --git a/pgserver/pg_catalog_handler.go b/pgserver/pg_catalog_handler.go
index 8dec651..84cb878 100644
--- a/pgserver/pg_catalog_handler.go
+++ b/pgserver/pg_catalog_handler.go
@@ -237,9 +237,9 @@ var pgCatalogHandlers = map[string]PGCatalogHandler{
 				return h.handleCurrentSetting(query)
 			}
 			//if pgCatalogRegex.MatchString(sql) {
-			//if isSpecialPgCatalog(query) {
-			//	return h.handlePgCatalog(query)
-			//}
+			if isSpecialPgCatalog(query) {
+				return h.handlePgCatalog(query)
+			}
 			return false, nil
 		},
 	},
diff --git a/pgserver/stmt.go b/pgserver/stmt.go
index d419385..c88e44e 100644
--- a/pgserver/stmt.go
+++ b/pgserver/stmt.go
@@ -278,7 +278,7 @@ func getPgCatalogRegex() *regexp.Regexp {
 			}
 			tableNames = append(tableNames, table.Name)
 		}
-		pgCatalogRegex = regexp.MustCompile(`(?i)\b(FROM|JOIN)\s+(?:pg_catalog\.)?(` + strings.Join(tableNames, "|") + `)`)
+		pgCatalogRegex = regexp.MustCompile(`(?i)\b(FROM|JOIN|INTO)\s+(?:pg_catalog\.)?(` + strings.Join(tableNames, "|") + `)`)
 	})
 	return pgCatalogRegex
 }