How to load existing db file to memory in Python sqlite3?

Question

I have an existing sqlite3 db file, on which I need to make some extensive calculations. Doing the calculations from the file is painfully slow, and as the file is not large (~10 MB), so there should be no problem to load it into memory.

Is there a Pythonic way to load the existing file into memory in order to speed up the calculations?

Answer 1

Here is the snippet that I wrote for my flask application:

import sqlite3 from io import StringIO  def init_sqlite_db(app):     # Read database to tempfile     con = sqlite3.connect(app.config['SQLITE_DATABASE'])     tempfile = StringIO()     for line in con.iterdump():         tempfile.write('%s\n' % line)     con.close()     tempfile.seek(0)      # Create a database in memory and import from tempfile     app.sqlite = sqlite3.connect(":memory:")     app.sqlite.cursor().executescript(tempfile.read())     app.sqlite.commit()     app.sqlite.row_factory = sqlite3.Row 

Answer 2

What about sqlite3.Connection.backup(...)? "This method makes a backup of a SQLite database even while it’s being accessed by other clients, or concurrently by the same connection." Availability: SQLite 3.6.11 or higher. New in version 3.7.

import sqlite3  source = sqlite3.connect('existing_db.db') dest = sqlite3.connect(':memory:') source.backup(dest)