DatabaseError：当前事务中止，命令被忽略，直到事务块结束？

I got a lot of errors with the message :

"DatabaseError: current transaction is aborted, commands ignored until end of transaction block"

after changed from python-psycopg to python-psycopg2 as Django project’s database engine.

The code remains the same, just don’t know where those errors are from.

This is what postgres does when a query produces an error and you try to run another query without first rolling back the transaction. (You might think of it as a safety feature, to keep you from corrupting your data.)

To fix this, you’ll want to figure out where in the code that bad query is being executed. It might be helpful to use the log_statement and log_min_error_statement options in your postgresql server.

To get rid of the error, roll back the last (erroneous) transaction after you’ve fixed your code:

from django.db import transaction
transaction.rollback()

You can use try-except to prevent the error from occurring:

from django.db import transaction, DatabaseError
try:
    a.save()
except DatabaseError:
    transaction.rollback()

Refer : Django documentation

So, I ran into this same issue. The problem I was having here was that my database wasn’t properly synced. Simple problems always seem to cause the most angst…

To sync your django db, from within your app directory, within terminal, type:

$ python manage.py syncdb

Edit: Note that if you are using django-south, running the ‘$ python manage.py migrate’ command may also resolve this issue.

Happy coding!

In Flask you just need to write:

curs = conn.cursor()
curs.execute("ROLLBACK")
conn.commit()

P.S. Documentation goes here https://www.postgresql.org/docs/9.4/static/sql-rollback.html

In my experience, these errors happen this way:

try:
    code_that_executes_bad_query()
    # transaction on DB is now bad
except:
    pass

# transaction on db is still bad
code_that_executes_working_query() # raises transaction error

There nothing wrong with the second query, but since the real error was caught, the second query is the one that raises the (much less informative) error.

edit: this only happens if the except clause catches IntegrityError (or any other low level database exception), If you catch something like DoesNotExist this error will not come up, because DoesNotExist does not corrupt the transaction.

The lesson here is don’t do try/except/pass.

I think the pattern priestc mentions is more likely to be the usual cause of this issue when using PostgreSQL.

However I feel there are valid uses for the pattern and I don’t think this issue should be a reason to always avoid it. For example:

try:
    profile = user.get_profile()
except ObjectDoesNotExist:
    profile = make_default_profile_for_user(user)

do_something_with_profile(profile)

If you do feel OK with this pattern, but want to avoid explicit transaction handling code all over the place then you might want to look into turning on autocommit mode (PostgreSQL 8.2+): https://docs.djangoproject.com/en/dev/ref/databases/#autocommit-mode

DATABASES['default'] = {
    #.. you usual options...
    'OPTIONS': {
        'autocommit': True,
    }
}

I am unsure if there are important performance considerations (or of any other type).

If you get this while in interactive shell and need a quick fix, do this:

from django.db import connection
connection._rollback()

originally seen in this answer

I encountered a similar behavior while running a malfunctioned transaction on the postgres terminal. Nothing went through after this, as the database is in a state of error. However, just as a quick fix, if you can afford to avoid rollback transaction. Following did the trick for me:

COMMIT;

I’ve got the silimar problem. The solution was to migrate db (manage.py syncdb or manage.py schemamigration --auto <table name> if you use south).

just use rollback

Example code

try:
    cur.execute("CREATE TABLE IF NOT EXISTS test2 (id serial, qa text);")
except:
    cur.execute("rollback")
    cur.execute("CREATE TABLE IF NOT EXISTS test2 (id serial, qa text);")

I just had this error too but it was masking another more relevant error message where the code was trying to store a 125 characters string in a 100 characters column:

DatabaseError: value too long for type character varying(100)

I had to debug through the code for the above message to show up, otherwise it displays

DatabaseError: current transaction is aborted

In response to @priestc and @Sebastian, what if you do something like this?

try:
    conn.commit()
except:
    pass

cursor.execute( sql )
try: 
    return cursor.fetchall()
except: 
    conn.commit()
    return None

I just tried this code and it seems to work, failing silently without having to care about any possible errors, and working when the query is good.

I believe @AnujGupta’s answer is correct. However the rollback can itself raise an exception which you should catch and handle:

from django.db import transaction, DatabaseError
try:
    a.save()
except DatabaseError:
    try:
        transaction.rollback()
    except transaction.TransactionManagementError:
        # Log or handle otherwise

If you find you’re rewriting this code in various save() locations, you can extract-method:

import traceback
def try_rolling_back():
    try:
        transaction.rollback()
        log.warning('rolled back')  # example handling
    except transaction.TransactionManagementError:
        log.exception(traceback.format_exc())  # example handling

Finally, you can prettify it using a decorator that protects methods which use save():

from functools import wraps
def try_rolling_back_on_exception(fn):
    @wraps(fn)
    def wrapped(*args, **kwargs):
        try:
            return fn(*args, **kwargs)
        except:
            traceback.print_exc()
            try_rolling_back()
    return wrapped

@try_rolling_back_on_exception
def some_saving_method():
    # ...
    model.save()
    # ...

Even if you implement the decorator above, it’s still convenient to keep try_rolling_back() as an extracted method in case you need to use it manually for cases where specific handling is required, and the generic decorator handling isn’t enough.

This is very strange behavior for me. I’m surprised that no one thought of savepoints. In my code failing query was expected behavior:

from django.db import transaction
@transaction.commit_on_success
def update():
    skipped = 0
    for old_model in OldModel.objects.all():
        try:
            Model.objects.create(
                group_id=old_model.group_uuid,
                file_id=old_model.file_uuid,
            )
        except IntegrityError:
            skipped += 1
    return skipped

I have changed code this way to use savepoints:

from django.db import transaction
@transaction.commit_on_success
def update():
    skipped = 0
    sid = transaction.savepoint()
    for old_model in OldModel.objects.all():
        try:
            Model.objects.create(
                group_id=old_model.group_uuid,
                file_id=old_model.file_uuid,
            )
        except IntegrityError:
            skipped += 1
            transaction.savepoint_rollback(sid)
        else:
            transaction.savepoint_commit(sid)
    return skipped

In Flask shell, all I needed to do was a session.rollback() to get past this.

I have met this issue , the error comes out since the error transactions hasn’t been ended rightly, I found the postgresql_transactions of Transaction Control command here

Transaction Control

The following commands are used to control transactions

BEGIN TRANSACTION − To start a transaction.

COMMIT − To save the changes, alternatively you can use END TRANSACTION command.

ROLLBACK − To rollback the changes.

so i use the END TRANSACTION to end the error TRANSACTION, code like this:

    for key_of_attribute, command in sql_command.items():
        cursor = connection.cursor()
        g_logger.info("execute command :%s" % (command))
        try:
            cursor.execute(command)
            rows = cursor.fetchall()
            g_logger.info("the command:%s result is :%s" % (command, rows))
            result_list[key_of_attribute] = rows
            g_logger.info("result_list is :%s" % (result_list))
        except Exception as e:
            cursor.execute('END TRANSACTION;')
            g_logger.info("error command :%s and error is :%s" % (command, e))
    return result_list

you could disable transaction via “set_isolation_level(0)”