Enable some sqlite and pysqlite options

jkseppan · jkseppan · commit 5866d94b82e5 · 2018-02-18T14:47:20.000+02:00
- synchronous=normal (fewer disk writes, still safe in WAL mode)
- foreign key enforcement
- log sql statements at debug level
- use sqlite3.Row (enables accessing columns by name)
diff --git a/lib/matplotlib/dviread.py b/lib/matplotlib/dviread.py
@@ -1037,8 +1037,17 @@ def __init__(self, filename=None):
 
         self.connection = sqlite3.connect(
                 filename, isolation_level="DEFERRED")
+        if _log.isEnabledFor(logging.DEBUG):
+            def debug_sql(sql):
+                _log.debug(' '.join(sql.splitlines()).strip())
+            self.connection.set_trace_callback(debug_sql)
+        self.connection.row_factory = sqlite3.Row
         with self.connection as conn:
-            conn.execute("PRAGMA journal_mode=WAL;")
+            conn.executescript("""
+                PRAGMA journal_mode=WAL;
+                PRAGMA synchronous=NORMAL;
+                PRAGMA foreign_keys=ON;
+            """)
             version, = conn.execute("PRAGMA user_version;").fetchone()
 
         if version == 0:
