Re: BUG #16351: PostgreSQL closing connection during requests with segmentation fault

Unfortunately, there isn't enough information here for anybody to reproduce
the issue.
Perhaps you can start by validating your own environment for any changes
since the
database server was running fine for almost a month before you started
seeing this
issue.

For anybody to be of any help, they'll need complete steps to reproduce
this issue,
and a core dump that carries enough debugging information to track the
problem.

On Wed, Apr 8, 2020 at 3:45 PM PG Bug reporting form <noreply(at)postgresql(dot)org>
wrote:

> The following bug has been logged on the website:
>
> Bug reference: 16351
> Logged by: Johannes Mols
> Email address: johannes(dot)mols(at)googlemail(dot)com
> PostgreSQL version: 10.12
> Operating system: Ubuntu 18.04
> Description:
>
> I originally posted this on StackExchange yesterday, but someone
> recommended
> me to post this here:
>
> https://dba.stackexchange.com/questions/264530/postgresql-closing-connection-during-requests
>
> I have a PostgreSQL 10.12 server running on an Ubuntu 18.04 Server. Since
> today, I am suddenly getting errors when querying data from a Python script
> running on the same machine, and in some edge cases also in pgAdmin 4.
>
> In about 50% of the cases, my Python script will fail to return any data
> because the DB server closed the connection. I am using psycopg2 and it is
> giving me the following error:
>
> psycopg2.errors.AdminShutdown: terminating connection due to administrator
> command
> server closed the connection unexpectedly
> This probably means the server terminated abnormally
> before or while processing the request.
>
> Interestingly, the same queries (which are simple "SELECT * FROM table"
> statements) run perfectly fine in pgAdmin. However, when I try to run the
> following query in pgAdmin, I get the message Connection to the server has
> been lost.
>
> select * from mytable where mycolumn <> ' '
>
> This query specifically worked fine a few days ago. I couldn't find any
> other examples where this happens in pgAdmin, but there is surely something
> wrong.
>
> What is weird is that the database has been running for over a month
> without
> any issues, and this only started today. I did try to restart the service
> to
> no avail.
>
> The logs are not making much sense to me, but there are several things
> wrong.
>
> The last few days, it constantly gave me the following message:
>
> 2020-04-06 19:43:26.959 CEST [7820] postgres(at)postgres FATAL: password
> authentication failed for user "postgres"
> 2020-04-06 19:43:26.959 CEST [7820] postgres(at)postgres DETAIL: Password
> does
> not match for user "postgres".
> Connection matched pg_hba.conf line 102: "host all all
>
> all md5"
>
> I am certain that I am using the correct password, as it does work 50% of
> the time of the queries. It is showing this message for the default
> postgres
> database and not my own, but it still confuses me why this happens as I'm
> using the default postgres user for both databases. I got this message a
> lot
> during the night where I was not doing anything with it either.
>
> For the actual error regarding the query from pgAdmin, this is what I get:
>
> 2020-04-07 11:25:18.891 CEST [5497] LOG: server process (PID 20569) was
> terminated by signal 11: Segmentation fault
> 2020-04-07 11:25:18.891 CEST [5497] DETAIL: Failed process was running:
> SELECT * FROM transactionoutputs WHERE fileheader <> ''
> 2020-04-07 11:25:18.891 CEST [5497] LOG: terminating any other active
> server processes
> 2020-04-07 11:25:18.891 CEST [20567] postgres(at)bitcoin WARNING:
> terminating
> connection because of crash of another server process
> 2020-04-07 11:25:18.891 CEST [20567] postgres(at)bitcoin DETAIL: The
> postmaster has commanded this server process to roll back the current
> transaction and exit, because another server process exited abnormally and
> possibly corrupted shared memory.
> 2020-04-07 11:25:18.891 CEST [20567] postgres(at)bitcoin HINT: In a moment
> you
> should be able to reconnect to the database and repeat your command.
> I can't seem to find any errors in the logs for the regular SELECT queries
> from my Python scripts, so I don't know why the connection is closed for
> this all the time. What is so confusing about this is that it worked
> perfectly fine just a yesterday, and I have not changed anything.
> Restarting
> PostgreSQL also did not help.
>
> I also constantly get this message when trying to query data through my
> Python API using Postman:
>
> 2020-04-07 11:25:18.891 CEST [9215] postgres(at)bitcoin WARNING: terminating
> connection because of crash of another server process
> 2020-04-07 11:25:18.891 CEST [9215] postgres(at)bitcoin DETAIL: The
> postmaster
> has commanded this server process to roll back the current transaction and
> exit, because another server process exited abnormally and possibly
> corrupted shared memory.
> 2020-04-07 11:25:18.891 CEST [9215] postgres(at)bitcoin HINT: In a moment
> you
> should be able to reconnect to the database and repeat your command.
>
> You can see the full log of the last ~3 days here:
> https://pastebin.com/iBC1G2Qg
>
> I'm not an expert with databases or Linux, so any help why this might
> happen
> and how I can figure out what exactly is happening is highly appreciated,
> thank you.
>
>

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