如何运行psycopg2。附加值（）未提交？

Question

我在跑步：

def db_connect():
    conn = psycopg2.connect(
        host=host,
        database=database, 
        user=user,
        password=password
    )
    return conn


data_to_insert = []
for a, b, c in data_source:  # len(data_source) > 100000
   data_to_insert.append(a, b, c) 


def insert_to_table():

    request = "INSERT INTO tablename " \ 
              "(a, b, c) " \
              "VALUES " \
              "%s "

    do_commit = False

    with db_connect() as conn:
        with conn.cursor() as cur:
                psycopg2.extras.execute_values(cur, request, data_to_insert, template=None)

        if do_commit:
            conn.commit() # this line could be completely omitted 

但它仍然承诺。有可能避免吗？如果我没记错的话，其他比较慢的方法，比如cur.execute()，都没有这个问题。你知道吗

psycopg2.__version__是2.8.2 (dt dec pq3 ext lo64)

PostgreSQL 10.10（Ubuntu10.10-0ubuntu0.18.04.1）在x86泷u 64-pc-linux-gnu上，由gcc（Ubuntu7.4.0-1ubuntu1~18.04.1）7.4.0编译，64位

Answer 1

默认情况下，conn将在脱离with语句后提交。你知道吗

Starting from version 2.5, psycopg2’s connections and cursors are context managers and can be used with the with statement:

with psycopg2.connect(DSN) as conn:
    with conn.cursor() as curs:
        curs.execute(SQL) 

When a connection exits the with block, if no exception has been raised by the block, the transaction is committed. In case of exception the transaction is rolled back.

因此，与其这样做：

if do_commit:
    conn.commit()

做

if not do_commit:
    conn.rollback()