apps.py 文件源码

def activate_pragmas_per_connection(sender, connection, **kwargs):
        """
        Activate SQLite3 PRAGMAs that apply on a per-connection basis. A no-op
        right now, but kept around as infrastructure if we ever want to add
        PRAGMAs in the future.
        """

        if connection.vendor == "sqlite":
            cursor = connection.cursor()

            # Shorten the default WAL autocheckpoint from 1000 pages to 500
            cursor.execute(CONNECTION_PRAGMAS)

            # We don't turn on the following pragmas, because they have negligible
            # performance impact. For reference, here's what we've tested:

            # Don't ensure that the OS has fully flushed
            # our data to disk.
            # cursor.execute("PRAGMA synchronous=OFF;")

            # Store cross-database JOINs in memory.
            # cursor.execute("PRAGMA temp_store=MEMORY;")