This is an example demo of how I was able to pass an sqlite3 database in memory between threads.

multi_threaded_memory_db.py

import sqlite3
from threading import Thread
import time

conn = sqlite3.connect("file::memory:?cache=shared", uri=True, check_same_thread=False)
conn.execute("PRAGMA journal_mode=MEMORY")
c = conn.cursor()

# s = time.time()
c.execute('CREATE TABLE test (test TEXT, test2 TEXT)')
c.execute('INSERT INTO test VALUES (?,?)', ('test', 'yo yo',))
c.execute('SELECT * FROM test')
conn.commit()
# print(f'time taken {time.time() - s}')
print(c.fetchall(), '\n\n')

def test_func():
    # s1 = time.time()
    con = sqlite3.connect("file::memory:?cache=shared", uri=True)
    cur = con.cursor()
    cur.execute('SELECT * FROM test')
    # print(f'time taken {time.time() - s1}')
    print(cur.fetchall())
    # alternativly, you could skip making the new connecton and curser objects and use the old one as the
    # check_same_thread argument is enabled. Only do this as a last resort if the original memory connection
    # can't be connected to, as it sometimes happens to me, and I think it means its outside of the memorys
    # scope of reach


time.sleep(1)
while True:
    Thread(target=test_func).start()
    # test_func()
    time.sleep(1)