Alembic version out of sync between alembic vs db

[kingkong-cmd]

I use flask-migrate, and when I try to push (flask db upgrade) my latest migration file (0db152ce17b6) to the DB I get the below error:

ERROR [flask_migrate] Error: Online migration expected to match one row when updating '3fba6dfbb433' to '0db152ce17b6' in 'alembic_version'; 0 found

When I check my DB, the alembic version is 3fba6dfbb433, but when I run flask db heads and flask db history i get the below results. I am not sure what the above error means, and also what it means that the head is different from the alembic version? Can anyone please help point me in the right direction to fix this?

flask db heads
0db152ce17b6 (head)

flask db history
3fba6dfbb433 -> 0db152ce17b6 (head), empty message
b1cb58b9ca83 -> 3fba6dfbb433, empty message
4b27b6043409 -> b1cb58b9ca83, empty message
88f37cb5274b -> 4b27b6043409, empty message

[zzzeek]

turn on SQLAlchemy "debug" logging, if using alembic.ini this looks like:

# Logging configuration
[loggers]
keys = root,sqlalchemy,alembic

[handlers]
keys = console

[formatters]
keys = generic

[logger_root]
level = WARN
handlers = console
qualname =

[logger_sqlalchemy]
level = DEBUG
handlers =
qualname = sqlalchemy.engine

then we would want to see the full debug SQL output for the above operation as well as a complete stack trace.

other things:

1. this is just one specific database? do these errors occur on a clean database re-running new migrations?
2. what database / driver is this?
3. has this database been working "fine" and something happened? what precipitated it suddenly not working?
4. is this a devleopment DB you can just rebuild?

[zzzeek]

can you show us the output of "SELECT * FROM alembic_version" ?

[kingkong-cmd]

can you show us the output of "SELECT * FROM alembic_version" ?

It's 3fba6dfbb433

[zzzeek]

OK how about this:

test=> BEGIN;
BEGIN
test=*> UPDATE alembic_version SET version_num='0db152ce17b6' WHERE alembic_version.version_num = 
'3fba6dfbb433';
UPDATE 1
test=*> SELECT * FROM alembic_version;
 version_num  
--------------
 0db152ce17b6
(1 row)

test=*> ROLLBACK;
ROLLBACK

see that "UPDATE 1"? that "1" should say "1", not "0"

[kingkong-cmd]

This gives me the below. Not sure if the transaction in progress is just me messing up the SQL.

WARNING:  there is already a transaction in progress
UPDATE 0

[zzzeek]

hah. do this:

select pid, usename, state, query from pg_stat_activity;

look for other transactions that are hung opened, looking at the same table. or just restart your database.