所以我只是尝试使用Python的psycopg2删除并重新创建我的数据库。这是我的代码:
with psycopg2.connect(database="postgres", user="postgres", password="****") as conn:
with conn.cursor() as cur:
conn.autocommit = True # Explains why we do this - we cannot drop or create from within a DB transaction. http://initd.org/psycopg/docs/connection.html#connection.autocommit
cur.execute("DROP DATABASE crowdsurfer;")
cur.execute("CREATE DATABASE crowdsurfer;")
当我运行这个代码时,我得到
PS C:\Users\Nick\Documents\GitHub\CrowdSurfer\CrowdSurfer> python utils/sqlInit.py
Traceback (most recent call last):
File "utils/sqlInit.py", line 70, in <module>
run()
File "utils/sqlInit.py", line 21, in run
recreate_empty_database()
File "utils/sqlInit.py", line 40, in recreate_empty_database
cur.execute("DROP DATABASE crowdsurfer;")
psycopg2.OperationalError: database "crowdsurfer" is being accessed by other users
DETAIL: There is 1 other session using the database.
好吧,很公平。所以我打开了一个到postgres的连接,并在我的代码运行之前和运行期间查看了现有的处理过程。在我的代码开始之前,我们得到:
postgres=# select pid from pg_stat_activity
此命令返回一个PID 6052
这个过程是我做的,所以很好。下面是我在运行python代码时查询运行进程时得到的结果:
postgres=# select * from pg_stat_activity;
datid | datname | pid | usesysid | usename | application_name | client_addr | client_hostname | client_port | backend_start | xact_start | query_start |
state_change | waiting | state | query
12029 | postgres | 6052 | 10 | postgres | psql | ::1 | | 49842 | 2014-03-11 23:14:34.049-06 | 2014-03-11 23:14:58.938-06 | 2014-03-11 23:14:58.938-06 |
2014-03-11 23:14:58.938-06 | f | active | select * from pg_stat_activity;
142547 | crowdsurfer | 3952 | 10 | postgres | | 127.0.0.1 | | 49849 | 2014-03-11 23:14:57.489-06 | | 2014-03-11 23:14:57.491-06 |
2014-03-11 23:14:57.491-06 | f | idle | SET default_transaction_isolation TO 'read committed'
12029 | postgres | 7908 | 10 | postgres | | ::1 | | 49851 | 2014-03-11 23:14:57.556-06 | 2014-03-11 23:14:57.559-06 | 2014-03-11 23:14:57.559-06 |
2014-03-11 23:14:57.559-06 | f | active | DROP DATABASE crowdsurfer;
(3 rows)
python代码启动了两个进程!一个连接到postgres数据库,这是我明确做的。另一个连接到我要删除的数据库(crowdsurfer)。注意它是空闲的,并且它运行的查询被设置为默认的事务隔离为“read committed”
因此,将conn.autocommit设置为true似乎是在创建一个新进程???有什么想法,在这里做什么,使下降这个数据库?
目前没有回答
相关问题 更多 >
编程相关推荐