Re: Alter command getting stuck on a table

Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> writes:
>
>> On Tue, 2020-01-07 at 14:58 +0530, Shrikant Bhende wrote:
>>> I am trying to add a column to a table but it's not working, I have also tried
>>> reindex and drop on the same table but those commands are also getting stuck.
>
>> There is a concurrent session which has an open transaction which
>> holds some lock on the table in question.
>
> Yes, that looks like the cause. The pg_locks view could help you
> find the culprit session.

Yeah, and IMO the pg_blocking_pids($blocked-guys-pid) function is pretty
snazzy too :-)

> regards, tom lane
>
>
>

--
Jerry Sievers
Postgres DBA/Development Consulting
e: postgres(dot)consulting(at)comcast(dot)net